CA1241824A - Method and apparatus for connecting optical fibers - Google Patents
Method and apparatus for connecting optical fibersInfo
- Publication number
- CA1241824A CA1241824A CA000449347A CA449347A CA1241824A CA 1241824 A CA1241824 A CA 1241824A CA 000449347 A CA000449347 A CA 000449347A CA 449347 A CA449347 A CA 449347A CA 1241824 A CA1241824 A CA 1241824A
- Authority
- CA
- Canada
- Prior art keywords
- fibers
- groove
- support
- fiber
- rigid member
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/36—Mechanical coupling means
- G02B6/38—Mechanical coupling means having fibre to fibre mating means
- G02B6/3801—Permanent connections, i.e. wherein fibres are kept aligned by mechanical means
- G02B6/3803—Adjustment or alignment devices for alignment prior to splicing
- G02B6/3805—Adjustment or alignment devices for alignment prior to splicing with a fibre-supporting member inclined to the bottom surface of the alignment means
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/36—Mechanical coupling means
- G02B6/38—Mechanical coupling means having fibre to fibre mating means
- G02B6/3801—Permanent connections, i.e. wherein fibres are kept aligned by mechanical means
- G02B6/3806—Semi-permanent connections, i.e. wherein the mechanical means keeping the fibres aligned allow for removal of the fibres
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/44—Mechanical structures for providing tensile strength and external protection for fibres, e.g. optical transmission cables
- G02B6/4439—Auxiliary devices
- G02B6/444—Systems or boxes with surplus lengths
- G02B6/4441—Boxes
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/36—Mechanical coupling means
- G02B6/3616—Holders, macro size fixtures for mechanically holding or positioning fibres, e.g. on an optical bench
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/36—Mechanical coupling means
- G02B6/3628—Mechanical coupling means for mounting fibres to supporting carriers
- G02B6/3648—Supporting carriers of a microbench type, i.e. with micromachined additional mechanical structures
- G02B6/3652—Supporting carriers of a microbench type, i.e. with micromachined additional mechanical structures the additional structures being prepositioning mounting areas, allowing only movement in one dimension, e.g. grooves, trenches or vias in the microbench surface, i.e. self aligning supporting carriers
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/24—Coupling light guides
- G02B6/36—Mechanical coupling means
- G02B6/38—Mechanical coupling means having fibre to fibre mating means
- G02B6/3807—Dismountable connectors, i.e. comprising plugs
- G02B6/381—Dismountable connectors, i.e. comprising plugs of the ferrule type, e.g. fibre ends embedded in ferrules, connecting a pair of fibres
- G02B6/3818—Dismountable connectors, i.e. comprising plugs of the ferrule type, e.g. fibre ends embedded in ferrules, connecting a pair of fibres of a low-reflection-loss type
- G02B6/382—Dismountable connectors, i.e. comprising plugs of the ferrule type, e.g. fibre ends embedded in ferrules, connecting a pair of fibres of a low-reflection-loss type with index-matching medium between light guides
Abstract
A B S T R A C T
The apparatus comprises: firstly a support (4) having at least one surface (40) which is made of soft, elastically deformable material and which includes a groove (5) suitable for receiving the ends of two optical fibers (1, 2) to be connected in end-to-end contact; and secondly a member (8) which is kept bearing against the support surface and the ends of the optical fibers.
Said member (8) comprises a polished rigid part such that keeping it bearing against the support surface (40) exerts a compression action on the said ends of the fibers, giving rise to radial reaction from the wall of the groove against the ends of the fibers, and thus ensuring that the fibers are aligned.
The apparatus comprises: firstly a support (4) having at least one surface (40) which is made of soft, elastically deformable material and which includes a groove (5) suitable for receiving the ends of two optical fibers (1, 2) to be connected in end-to-end contact; and secondly a member (8) which is kept bearing against the support surface and the ends of the optical fibers.
Said member (8) comprises a polished rigid part such that keeping it bearing against the support surface (40) exerts a compression action on the said ends of the fibers, giving rise to radial reaction from the wall of the groove against the ends of the fibers, and thus ensuring that the fibers are aligned.
Description
The invention relates to connecting optical fibers. -Optical fiber connectors already exist for connec-ting optical fibers. They comprise two plugs into which the fibers to be connected are slid, and a third member or connection par-t which is interposed between the plugs and which ena~les continuity to be obtained in the light guide. An essential characteristic of optical fiber connectors is that they are intended to be assembled and disassembled at will by the user.
~his essential practical advantage is obtained at the cost of non-negligible technical complexity, as is well known to the person skilled in the art.
~he present invention relates to apparatus of a different type which is not intended to provide a connection between optical fibers which can be released at will, but ra-ther it is intended to provide a stable connection which may be modified from time to time a3 required. By analogy with electricity, the present invention may be considered to provide a kind of optical fiber connection strip, whereas the above-mentioned connectors correspond in contrast to the various farnilies of releasable connectors.
In this respect, preferred embodiments of -the present invention provide connection means which are cheaper and easier to use than such connectors, and which are particularly - applicable for installing complete distribution networks using optical fibers, for example. In æuch a network; muIti-fiber cables need -to be connected or to be divided in cabinets or chests for making junctions or branch connections, thereby 3 enablin~the network operator to set up and subsequently to - modi-fy connections to various ~ubscribers.
It may be observed that an optical fiber connector can also perform this function. ~1owever, a connector suffers ~rom the technical complexity already mentioned, which naturally leads to greater cost Further, opticc~l fiber connec-tors include two parts which are permanently fixed to each of the ~ibers to be connected thereby.
~his essential practical advantage is obtained at the cost of non-negligible technical complexity, as is well known to the person skilled in the art.
~he present invention relates to apparatus of a different type which is not intended to provide a connection between optical fibers which can be released at will, but ra-ther it is intended to provide a stable connection which may be modified from time to time a3 required. By analogy with electricity, the present invention may be considered to provide a kind of optical fiber connection strip, whereas the above-mentioned connectors correspond in contrast to the various farnilies of releasable connectors.
In this respect, preferred embodiments of -the present invention provide connection means which are cheaper and easier to use than such connectors, and which are particularly - applicable for installing complete distribution networks using optical fibers, for example. In æuch a network; muIti-fiber cables need -to be connected or to be divided in cabinets or chests for making junctions or branch connections, thereby 3 enablin~the network operator to set up and subsequently to - modi-fy connections to various ~ubscribers.
It may be observed that an optical fiber connector can also perform this function. ~1owever, a connector suffers ~rom the technical complexity already mentioned, which naturally leads to greater cost Further, opticc~l fiber connec-tors include two parts which are permanently fixed to each of the ~ibers to be connected thereby.
2 ~ 2 ~
Similarly9 it is often useful in a labora-tory to have simple, fast and effective means for making fiber-to fiber connections, where fitting a complete connector would be slow, expensive and not removable from each of the fiber ends concerned, as ~entioned above.
In this context, preferred embodiments of the invention also solve the tricky problems of connecting fibers end to end in a simple manner, which proble~s are essentially due to the very small size and to the fragility of the fibers. The present trend is for the central or "core" part optical fibers to be made to ever smaller diameters.
Another difficulty which preferred embodiments of the present invention solve is related to the fact that the fibers to be connected may have slightly different diameters due to manufacturing tolerances, to coming from different suppliers 9 or just to coming from different batches. Connections should be of substan~ially constant quality in spite of such varia-tions.
In a first aspect the present invention provides a method of connecting optical fibers, the method including a preparatory step of:
a) preparing the ends of at least two optical fibers for connection;
and comprising the improvement of the following step in which:
b) the ends of at least two fibers to be connected are inserted end-to~end in a groove provided in the surface o-f a support ~hich, at least at said surface, is made of a material that is soEter than the fibers and which is elas-tically deformable; and -the fibers are lightly urged against one another to ensure intimate contact between between their end ~aces; at the same time a polished rigid member is maintained bearing against said support surface thereby applying pressure to said -fibers giving rise to radial reaction from the wall of the groove against the ~ibers and thus ensuring that the fibers are in alignment.
~5 - ~he -fibers may be prepared using known techniques for this purpose. In particular~ plane end Eaces perpendicular to the axis o:E ~he fibers and o-~ the shiny mirror type are preferably
Similarly9 it is often useful in a labora-tory to have simple, fast and effective means for making fiber-to fiber connections, where fitting a complete connector would be slow, expensive and not removable from each of the fiber ends concerned, as ~entioned above.
In this context, preferred embodiments of the invention also solve the tricky problems of connecting fibers end to end in a simple manner, which proble~s are essentially due to the very small size and to the fragility of the fibers. The present trend is for the central or "core" part optical fibers to be made to ever smaller diameters.
Another difficulty which preferred embodiments of the present invention solve is related to the fact that the fibers to be connected may have slightly different diameters due to manufacturing tolerances, to coming from different suppliers 9 or just to coming from different batches. Connections should be of substan~ially constant quality in spite of such varia-tions.
In a first aspect the present invention provides a method of connecting optical fibers, the method including a preparatory step of:
a) preparing the ends of at least two optical fibers for connection;
and comprising the improvement of the following step in which:
b) the ends of at least two fibers to be connected are inserted end-to~end in a groove provided in the surface o-f a support ~hich, at least at said surface, is made of a material that is soEter than the fibers and which is elas-tically deformable; and -the fibers are lightly urged against one another to ensure intimate contact between between their end ~aces; at the same time a polished rigid member is maintained bearing against said support surface thereby applying pressure to said -fibers giving rise to radial reaction from the wall of the groove against the ~ibers and thus ensuring that the fibers are in alignment.
~5 - ~he -fibers may be prepared using known techniques for this purpose. In particular~ plane end Eaces perpendicular to the axis o:E ~he fibers and o-~ the shiny mirror type are preferably
3 ~ 2~
obtained b~ the method described in -the Applicants' ~rench patent application nwmber 78 0970~ (published under the number 2 ~22 604). This prior patent application describes apparatus for sectioning optical fibers, in which fiber end faces suitable for connection are obtained by cleaving the fibers.
Then, it is currently considered to be advantageous to strip -the covering from the end of each of the fibers.
Step b is preferably performed as ~ollows:
bl) the end face of a first one of the fibers is brought to substantially half way along the groove;
b2) the first fiber is fixed relative to the support;
b3) the end face of the second fiber is brought into contact inside the groove with the end face of the first fiber; and b~) the second fiber is also fixed relative to the support 9 at the opposite side thereof.
In a second aspect the present invention also provides apparatus for connecting optical fibers by implementing the above method.
The apparatus includes parts which are in common with prior known appara-tuses: it comprises firstly a support ha~ing at least one surface which is made of soft, elastically deformable material and which includes a groove suitable for receiving the ends of two optical fibers to be connected in end-to-end contact, and secondly a member which is kept bearing against the support surface and -the ends of the optical fibers.
Similar arrangements are described, for example, in US patents
obtained b~ the method described in -the Applicants' ~rench patent application nwmber 78 0970~ (published under the number 2 ~22 604). This prior patent application describes apparatus for sectioning optical fibers, in which fiber end faces suitable for connection are obtained by cleaving the fibers.
Then, it is currently considered to be advantageous to strip -the covering from the end of each of the fibers.
Step b is preferably performed as ~ollows:
bl) the end face of a first one of the fibers is brought to substantially half way along the groove;
b2) the first fiber is fixed relative to the support;
b3) the end face of the second fiber is brought into contact inside the groove with the end face of the first fiber; and b~) the second fiber is also fixed relative to the support 9 at the opposite side thereof.
In a second aspect the present invention also provides apparatus for connecting optical fibers by implementing the above method.
The apparatus includes parts which are in common with prior known appara-tuses: it comprises firstly a support ha~ing at least one surface which is made of soft, elastically deformable material and which includes a groove suitable for receiving the ends of two optical fibers to be connected in end-to-end contact, and secondly a member which is kept bearing against the support surface and -the ends of the optical fibers.
Similar arrangements are described, for example, in US patents
4 088 386, 4 1~2 561, and ~ 257 ~74.
However 7 in these prior documents, the member kept bearing against the support surface i8 always another body of soft material, possibly having grooves, and the elastic properties of both parts placed on either siae of the optical fibers is thus used in the~e prior docw~ents for a~ially wedging the ~ibers7 and -thus for ensuring their alignment.
The apparatus in accordance with the present invention uses a combina-tion of different means.
The apparatus comprises the above-defined means, ie.
firstly a support having at least one sur~ace which is made of .
soft, elastically deformable material and which includes a groove suitable for receiving the ends of two optical fibers to be connected in end-to-end contact, which ends preferably include plane end faces perpendicular to the fiber axis and having a shiny mirror type of surface9 and secondly a member which is kept bearing against the support surface and the ends of the optical fibers.
In accordance with the second aspect of the present invention, said member comprises a polished ri6id part such that keeping it bearing against the said support surface exerts a compression action on the said ends of the fibers, giving rise to radial reaction from the wall of the groove against the ends of the fibers 9 and thus ensuring that the fibers are aligned.
Thus, the present inven-tion goes against the teaching of the prior documents, in which the both parts between which the optical fibers are clamped are deformable.
In contrast, the presel1t invention ta`~es a~vantage of the excellent surface state of the polished rigid part, and uses this in co-opera-tion with a block of soft, elastically deformable material to provide a connection between two optical fibers9 or as is explained below, between two sets of optical fibers.
According to a particularly advantageous implementation of the present invention, the said polished rigid member is a transparent plate, preferably a plate of glass which is thick enough to ensure that it is rigid~
lhe apparatus preferably includes two clamps, one at each end of the support, for fixing the fibers relative to the support. ~he clamps are used in such a manner as to ensure that the fibers are urged towards each other. ~he permanent axial thrust thus exerted on the fibers ensures that close contact is maintained over time between the end faces of the fibers in the groove.
In a multiple connection embodiment, the apparatus comprises a plurali-ty of grooves whose axes are preferably substantially parallel, thereby enabling fibers in two different sets of fibers to be connected end-to-end in pairs.
Two multi-fiber cables can thus be interconnected, fiber-to-
However 7 in these prior documents, the member kept bearing against the support surface i8 always another body of soft material, possibly having grooves, and the elastic properties of both parts placed on either siae of the optical fibers is thus used in the~e prior docw~ents for a~ially wedging the ~ibers7 and -thus for ensuring their alignment.
The apparatus in accordance with the present invention uses a combina-tion of different means.
The apparatus comprises the above-defined means, ie.
firstly a support having at least one sur~ace which is made of .
soft, elastically deformable material and which includes a groove suitable for receiving the ends of two optical fibers to be connected in end-to-end contact, which ends preferably include plane end faces perpendicular to the fiber axis and having a shiny mirror type of surface9 and secondly a member which is kept bearing against the support surface and the ends of the optical fibers.
In accordance with the second aspect of the present invention, said member comprises a polished ri6id part such that keeping it bearing against the said support surface exerts a compression action on the said ends of the fibers, giving rise to radial reaction from the wall of the groove against the ends of the fibers 9 and thus ensuring that the fibers are aligned.
Thus, the present inven-tion goes against the teaching of the prior documents, in which the both parts between which the optical fibers are clamped are deformable.
In contrast, the presel1t invention ta`~es a~vantage of the excellent surface state of the polished rigid part, and uses this in co-opera-tion with a block of soft, elastically deformable material to provide a connection between two optical fibers9 or as is explained below, between two sets of optical fibers.
According to a particularly advantageous implementation of the present invention, the said polished rigid member is a transparent plate, preferably a plate of glass which is thick enough to ensure that it is rigid~
lhe apparatus preferably includes two clamps, one at each end of the support, for fixing the fibers relative to the support. ~he clamps are used in such a manner as to ensure that the fibers are urged towards each other. ~he permanent axial thrust thus exerted on the fibers ensures that close contact is maintained over time between the end faces of the fibers in the groove.
In a multiple connection embodiment, the apparatus comprises a plurali-ty of grooves whose axes are preferably substantially parallel, thereby enabling fibers in two different sets of fibers to be connected end-to-end in pairs.
Two multi-fiber cables can thus be interconnected, fiber-to-
5 ~ 32~
fiber, or a single multi-fiber cable can be connected to a plurality o~ single fiber cables.
The Applican~ has further observed that the polished portion of the rigid plate or member need not necessarily be plane, and on the contrary it may be curved in shape relative to the axis of the groove or grooves. Preferably, the polished portion of the rigid member has a closed right cross section, which may be circular or substantially circular, or else it may be polygonal or substantially polygonal.
In an advantageous embodiment, the polished portion of the rigid plate and the groove-carrying surface are two geometrically similar surfaces, which are quasi complementary and which overlap slightly in the rest po~sition such that placing one against the other requires thrust to be exerted.
More generally, the groove-carrying surface and the polished portion of the rigid plate may be a pair of homologous and/or tangential surfaces æuitable for exerting said bearing force against one another by co-operation of their respective shapes. The elastic portion may in particular be made in several parts such that its outer contour or envelope defines the groove-carrying surface.
In a first family of embodiments? the elastic portion is inside and the rigid member is outside.
In a second family of embodiments the elastic portion is outside and the rigid member is inside. In this case, the rigid member may be provided wi-th a central channel which is advantageous in some applications.
~mbodiments and of the invention are described by way of example, with reference to the accompanying drawings, in which:
~ igure 1 is a perspective view of apparatus in accordance with the invention for making a single fiber connection 7 however, the apparatus shown can be used as a building block in a modular ~ulti-fiber system, ie. for interconnecting -two se-ts of optical fibers;
Figure 2 is a diagrammatlc plan view of the apparatus shown in Figure l;
.
~ igure 3 reproduces portions o~ Figure 2 to a larger scale to bring out details of its structure;
Figures 4 to 9 are perspective views showing various different shapes of grooJe ~lich can be used in the present invention;
Figure 10 i5 a longitudinal section through the ends o~
two interconnected optical fibers which co operate with one another via an index-matching liquid;
Figure ll is a cross section through a fiber as held in a groove showing the co-operation between a block o~ elas-tic ma-terial an~ a rigid p]ate at the end o-f an optical fiber;
~ igure 12 is a perspective view illustrating a particular shape of composite groove usable in apparatus in accordance with the invention, the groove tapers from an inlet end in order to co-operate with both a stripped end portion of an optical fiber and an adjacent portion which is still in its covering;
Figure 13 is a cross section through a variant apparatus in accordance with the invention in which the portion made of soft material is constituted by a plurality of parts;
~igure 14 is a diagrammatic perspective view of a multi-~iber connection apparatus in accordance with the invention;
Figure 15 is a diagrammatic perspective view of the outside of an optical fiber cable interconnection housing enclosing apparatus in accordance with the present inven-tion;
~igure 1~ is a perspec-tive view o~ apparatus in accordance with the invention of circular cross section and with the rigid member on the outside;
~igure -17 is a perspective view o~ apparatus in accordance wi-th -the invention O:e circular cross section and with the rigid member on the inside;
Figure 1~ is a perspective view of apparatus in accordance ~ith the inven-tion having a closed polygonal cross section with the rigid member on the outside;
~igure 19 is a perspective view Oe apparatus in accordance with the invention having a closed polygonal cross sec-tion with the rigid member on the inside;
Figures 20 and ~1 are cross section views through apparatuses comparable -to the Figure 16 apparatus, but in which the support of soft material is made o~ up fron a plurality of parts, ~ igure 22 is a perspective view of a variant apparatus in accordance with the invention, t~liS apparatus being fitted with means that make it particularly simple to set up the required axial thrust on the optical fibers, one of the apparatus is shown open while the other end is sho~m closed; and ~igure 23 is a plan view of the Figure 22 apparatus, with the end that is sho~m open in Figure 22 being shown dismantled in Figure 23.
Optical fiber technology makes frequent lse of shapes. In this respect the accompanying dra~;ings are considered to constitute an integral part of the present description for contributing wherever necessary to the definition of the invention and to the sufficiency of the description thereof.
In the figures, reference numeral 1 designates a first optical ~iber and reference numeral 2 designates a second optical ~iber~ Their ends which have been prepared by stripping off a covering are designated 11 and 12 respectively. In most cases the point of contact between the two ends is not shown.
As indicated above, the ends of two optical fibers are initially prepared by stripping off a portion of covering7 and by preparing end faces for connection, which faces are plane, perpendicular to the fiber axes, and have a shiny mirror type of surface. The person skilled in the art can be ~onsidered to know how to strip off the covering from an optical fiber. ~nd faces which are plane, perpendicular, and have a shiny mirror ~ -type sur~ace can be obtained advantageously by applying the teaching of the above-mentioned ~rench patent application number 78 09703~
The method in accordance with the invention makes use of a ~rame which bears an overall reference numeral 3. The frame comprises a base 31, having t1,Jo rising side walls 32 and 33 which retain an optical fiber support generally designated ~ of material which is softer than the fibers and which is 8 ~ 2~
elastically deformable. The support 4 has an upper surface 43 in which there is at least one fiber-guiding groove 5.
The groove comprises a central portion 5 between two end portions 61 and 62 of larger cross section The outside ends of the end portions 61 and 62 are terminated by flared openings 71 and 72. The central portion 5 and the end portions 61 and 62 are geometrically cylindrical or prismatic in shape, ie.
- they are of constant cross section~ with the central portion having a smaller cross section than the end portions, while the flared openings are frusto conical or pyramidal in shape, and in general have a cross sec-tion of the same shape as the adjacent end portion of the groove.
A polisned rigid plate 8 is kept bearing against the surface 40 of the support ~. In the embodiment shown in Figure 1, the polished rigid plate is held in place by inwardly directed hook-shaped flanges 34 and 35 running along the top edges of the side walls 32 and 33 of the frame 3. ~he support of soft mRterial 4 is thus compressed around four sides by the frame 3 and the rigid plate 8.
The previously prepared ends 11 and 12 of the two optical fibers 1 and 2 wnich terminate in end faces 12 and 22 are - inserted into opposite ends of the groove 5 and light thrust is maintained on each of them to ensure intimate end-to-end contact of their end faces inside the groove. The fact that the plate 8 bears down on the surface 40 of the support 4 means that the ends of the fibers are subjected to a compressive action ~hich gives rise to an opposing radial reaction on the ends of the fibers by the walls (51, 52) of -the groove, thereby aligning the fibers (see ~igure 11).
The fibers are preferably inserted into the apparatus in sequence. In which case the fibers are connected as follows:
1) The end face 12 of a first one of the fibers (in this case the fiber 1) is brought to substantially the middle of the groove 5 as shown in Figure 3.
2) The fiber 1 is fixed relative -to the support. As an example of a suitable means for fixing the fiber, Figure 1 shows a fiber clamp comprising spring jaws 15 having a base ~J~
plate 16 ixed -to the base 31 of the frame 3 and two jaw plates 17 of soft material which are pressed together by the ~spring clamp and be-tween ~hich the optical fiber is held.
3) The end face 22 of the second optical fiber 2 is then moved along -the groove 5 to come into contact with the end face 12 of the first optical fiber 1 (see ~igure 3).
4) The second optical fiber 2 is likewise fixed relative to the support by a second spring clamp 25 which is fixed via its base plate 26 to the other el1d of the base plate 31 of the frame 3~ As before, the clamp uses two jaw plates 27 of soft material for actual clamping contact with the fiber.
It is advantageous to keep -the fibers slightly buckled during each of the above steps, thereby ensuring axial thrust on each of the fibers towards the other fiber. A permanent axial thrust can thus be set up which ~1ill ensure that intimate contact is maintained over long periods of time between the end faces of the fibers. The slight buckling may be obtained by having clamps 15 and 25 ~hich are slightly off-axis relative to the groove 5, or else by having clamps which are on axis but with slightly too long a portion of fiber between each clamp and the point of contact between the end faces. ~he position of the clamps may be axially adjustable to ensure a desired degree of buckling.
~he groove 5 is preferably filled with index matching liquid before the fibers are inserted therein in ordér to improve light transmission between the fibers (see Figure 10).
It has been observed, that in addition -to this known effect of index matching li~uid, the presence of the liquid in the groove also has the effect of automatically cleaning the zone between the end faces 12 and 22 because of the piston effect of inserting the fibers in the groove 5 along axes 19 and 29.
Excess liquid is expelled in particular along the bottom notch 53 of -the groove, and also a]ong the upper passa~es 54 and 55 next to -the rigid plate 8 (see ~igure 11).
In practice it is useful to apply light to the fibers to - be connected. This can be done either via their respective other ends, or else, and preferably, by injecting light through .. . .. . _ _ 1 o ~',2fL'~
the sides of the fibers through their coverings. ~he injected light may be pulsed particularly if it is injected through the sides. This has the effect of causing a point of light to appear at each of the fiber end faces 12 and 22. As the fibers approach each other the points of light can be seen to get closer together. Intimate end-to-end contact between the end faces 12 and 22 can be considered to have been obtained when the points of light become highly attenuated or practically disappear.
This indication of good contact by means of injected light naturally requires the rigld plate 8 to be transparent.
It is indicated above that the fibers have their covering stripped off over an end portion and that their end faces are specially prepared to obtain the good optical characteristics for interconnection. In ~igures 1 to 3 the stripped end portions of the fibers are referenced 11 and 12 respectively.
These are the portions of the fibers which are inserted in the central portion 5 of the groove.
As a result an optical fiber connection apparatus is obtained in which a support 4 made of soft elastically deformable material has a straight groove 5 in at least one surface 40 thereof and suitable for receiving in end-to-end contact the ends 11 and 12 respectively of two optical fibers 1 and 2 to be connected 9 each of the fibers having an end face 12 or 22 respectively which is perpendicular to the axis of the fiber and which has a shiny mirror type of surface. In accordance with the present invention the member which keeps the fibers pressed against said surface of the support is a rigid polished plate 8 which applies the said compressive action with the advanta~es that result therefrom.
3 It is hiehly adv mtc~eouC; to have enlarged grooves 61 and 62 at each e1d of the central portion 5 for receiving op-tical ~iber from whicl1 the covering has not been stripped. These enlarged portions 61 and 62 are best seen in Figures 2 3 and 12. Finally each of the grooves has a flared inlet portion.
Figure 2 shows both flared inlet portions 71 and 72 .rhile Figures 3 and 12 show the inlet portion 71 to a larger scale.
In the embodi1nent of the invention described above, the support of soft material 4 is made from a single block of material.
~ he groove 5 per se, ie. the central portion thereof, may have various shapes.
~ igure 4 shows a first shape in which the groove 5 has a Y-shaped cross section with two sides 51 and 52 and an apex 53.
The sides 51 and 52 are symmetrically disposed about an axis 54 which is perpendicular to the surface 40 of the support block.
With reference to Figure 12, it can be seen how such a groove 5 of symmetrical trian~ular section can run into an adjacen-t length of groove 61 which ls of larger cross section so as to be able to receive a fiber still inside its covering without being too tight a fit. In particular there is a progressive transition from the larger section portion 61 to the smaller section portion 5. Finally the larger groove 61 termina-tes in a flared portion 71 having sides 74 and 75 which remain symmetrical about a plane perpendicular to the surface 40 and which lead to an end face 41 of the support 4~
o Figure 13 shows a variant emboAiment of the present invention in which the support of soft ma-terial is made up from a plurality of parts. A rigid bottom pla-te 10~ has a plurality of rods of soft material 104 fixed in parallel thereon in mutual contact to define a plurality of grooves 5 between adjacent rods 104. ~he rods 104 may be glued -to the bot-tom plate 103, for example. A rigid plate of polished ~lass 108 is pressed against -the otner side of the rods 104 in such a manner tha-t they are sandwiched between the plates 103 and 108, which are themselves held together by channel section side clamps 133 and 134. The resulting groovns 5 are ~enerally Y shaped, bu-t with curved sides that are convex as seen from inside the grooves. Many other shapes of groove 5 could be produced in this manner by using rods of suitable shapes.
Examples of other shapes of groove are now described with reference to Figures 5 to 9. These shapes may be formed in a single block of soft material or else they may be formed by juxtaposin~ two suitably- shaped rods, as shown in ~igure 13.
1 2 ~L~
Figure 5 shows a piece of soft material 4 having a groove cf rectang,llar or square cross section. It has two vertical sides 151 and 153 and a hori~ontal floor 152.
Figure 6 sho~"s a groove 5 has a cross section which is in 5 four segments 251, 252, 254, and 255. ~he bottom of the groove is referenced 25~.
~he groove shape shown in ~igure 6 is symmetrical about a plane perpendicular to the surface 40, but asymrnetrical shapes are also possible. Figure 9 shows such a shape. In this embodiment, the r~roove 5 has a cross section defined by a sloping side 551 and a vertical side 552 with the bottom of the groove being referenced 550. The vertical side 552 coincides with the plane 554 perpendicular to the top surface 40 of the support of soft material 4.
In the rernaining shapes that are de6cribed below, the groove cross section is defined by one or more curved segments, ~hich may by combined with rectilinear segments.
~igure 7 shows a ~roove 5 having a semicircular cross section like guttering 350, with the edges of the guttering 351 and 352 meeting the top sur-face 40 of the support 4.
In contrast, Figure 8 shows a groove 5 of generally V-shaped cross section made up of two quarter circles 451 and 452 meeting at a cusp at the bottom of the groove.
It is recalled that apparatuses described in previously known documents make use of two part~s w11ich are both made of soft material and placed on either si1e of the ends of the fibers to be joined, relying on the elas-ticity of the two parts to bring the fibers into adsqla-te alignment.
In a manner which is a priori unexpected, it has been observed that the use of a por-tion of soft material in conjunction with a rigid pla-te on the other æide of the fiber provides suEficient alignment of the fibers to be connected to ensure good optical interconnection between -the fibers. Initial tests by the Applicant have shown that attenuation of about one tenth of a decibel is to be ohtained at 511,-'h an interconnection, which thus constitutes an excellent optical connection.
2~
It has been observed that the method and apparatus in accordance with the invention function well even if the fibers to be interconnected are of slightly different diameters, due to manufacturing tolerances for e~ample (such as fibers taken from different batches or from di~erent sllppliers). The present invention is also remarkable for its simplicity and for the way it is well adapted to the fra~ility and small size of the fibers.
In a particular embodiment, the top plate ~ is a plate of glass of suitable thickness to ensure its rigidit~. It appears that a thickness of one millimeter is adequate. lhe support of soft material, or the rods of soft material as the case may be, are molded or machined in a silicone elastomer type of material such as silastene which is sold by the Rhone-Poulenc company.
~5 lhe frame may be made of metal. Finally, the in~1ex matching liquid is preferably a silicone oil such Dow Corning's liquid N SI 200 (viscosity 50 cp).
A more complex embodiment of the invention is now described with reference to Figures 14 and 15~
In this embodiment, -the support of soft material is referenced 104 and has a plurality of grooves 105. In order to simplify the drawing, the grooves 105 are shown as being of constant sec-tion in Figure 14, whereas, in practice, they are preferably in the form of a central portion of small æection with two end portions of larger section as described above, eg.
with reference to Figure 12. The support 104 is mounted on a base 103 having lugs 138 and 139 ~or fixing to an underlying surface (not shown). The ends of -the base 103 have upwardly directed risers 132 and 133 which fold over at -the top to 3 provide inwardly direc-ted flanges 134 and 135 for holding down a plate of glass 108 pressed a~ainst the grooved top surface of the support of soft material 104 as in the above-described embodiment. The uncovered faces of the support block are referenced 141 and 142. In Figure 14, onl~ one optical fiber connection is sho~m between fibers 101 and 102 which meet end-to-end in the middle of one of the grooves 105.
Two clamping strips are 115 and 125 are dlsposed on ei-ther side of the su~port block 104, all~ eae~l of them has its own fixing lugs 116 or 126 for fixing to the same sur~ace (not shown) as the base plate 103 is fixed. The clarnpin~ strip3 nave tra,ls~e~ ,assa~es for individual fibers in the non-stripped state (only two fibers 101 and 102 are shown). ~ac'n fiber is lodged-in its own elastomer sleeve (not shown) which is located in a channel 118 and which is held in place by a screw 119. ~he elastomer serves to prevent microcurves or even breaks in the optical fibers, which would impair light transmission. It can be seen -that the two optical fibers shown are slightly buckled as before.
In spite of only one connection being shown explicitly, it is clear that the apparatus sho-~1 in Figure 14 can be used for interconnecting in pairs a plurality of optical fibers from two different sets of fibers each including ten different fibers.
With reference to Figure 15, a protective housing 100 encloses apparatus of the type shown in Figure 14. The housing 100 has passages suitable for passing individual optical fibers or for passing an optical fiber cable in sealed manner to the inside of the housing. Although it is possible to interconnect two ten-fiber cables to each other~ the housing shown in ~ ure 15 represents a slightly different arrangement where ten single fiber cables 101A to 101J enter the housing through one wall, whereas a single ten-fiber cable 102 leaves the housing through an opposite wallO
The flxing lugs 138, 139, 116 and 126 shown in ~igure 14 are naturally fixed to another wall o~ the housing 100.
Other embodiments of the invention are now described in which either the rigid plate, or the soft support, or both are no-t plane mernbers. Nonetheless, the various groove cross sections described above can s-till be freely selected.
~ikewise, the following features which have already been described in relation to a plane embodiment can still apply:
1) The optical fibers are caused to buckle slightly on entering the apparatus to ensure suitable end-to-end contact pressure.
2) Index matching liquid is used, and the same piston effect takes place.
1 5 ~ 2~
~) Light can be used as a guide to determinin~ when good contact has been obtained.
~) ~he outside member of the apparatus should therefore be transparent over at least a portion of the visible spectr-um so that the contact determining points of light can be seen.
5) Each multi-fiber apparatus shown could readily be adapted to single fiber connection where required.
~ inally, it is ass~ned that the pairs of fiber ends to be interconnected have been suitably prepared to obtain end faces which are plane, perpendicular to the -fiber axes, and which have a shiny mirror type of r,urrace. The protective coverings are preferably stripped off over a suitable length.
Figure 16 shows a rigid member 208 in the for~ of a cylindrical glass tube having a cross section which is in -the form of a circular ring. A support of soft material 204 is a push fit inside the glass tube 208. The periphery of the support has seven~equi-spaced grooves such that the periphery of the support member 2Q4 constitutes the groove-carrying surface 240. Only one of the grooves is shown in detail. As mentioned above, the apparatus could be made to have only a - single groove.
Figure 17 shows a reciprocal configuration in which the rigid member is in the form of a solid cylinder 308 inside the - support 304 which is in the form of a tight-~itting sleeve of cof-t material disposed around the rigid member. The cross section of the support is a circular ring and it has seven longitudinally extending grooves running along its inside wall.
Only one of the grooves is shown in full, and indeed -there need only be one such groove. The groove-carrying surface is referenced ~40.
Instead of bein~ of truly circular sross section, as shown in Figures 16 and 17, the apparatus can be made to have a poly-gonal cross sec-tion, which may be regular or irregular.
Figures 18 and 19 show two fur-ther embodimen-ts generally equivalent to those of Figurss 16 and 17 respectively, except that the rnembers are of rectangular cross section. The person skilled in the art will understand tha-t various other shapes can readily be used~ for example, the edges of the polygonal shapes could be rounded or chamfered.
In Figure 18, as in ~igure 16, the rigid member 408 is on the outside. The support of soft material 404 is inside the rigid member and has three grooves running along its upper plane surface (as disposed in the figure). ~he closed groove-carrying surface is referenced 440 in this case. ~hree fibers 1A, 1~, and 1C arrive at one end of the apparatus, while -three other fibers 2A, 2~, and 2C arrive at the other endO ~aking the fibers 1A and 2A by way of example7 their ends 11A and 21A
meet substanti~lly at the middle of the cen-tral groove 5~
Similarly ~igure 19 shows a reciprocal configuration in which the rigid member 50~ is insiae and is of rectangular cross section. The suppor-t 504 of soft material is on the outside and its inside surface 540 (ie. the surface including all four inside planes of the support 504) includes three longitudinally extending grooves in the top plane thereof.
In the embodi~ents described above, the touching portions of the rigid polished plate and the groove-carrying surface are geometrically similar, are substantially complementary, and are so dimensionea as to overlap slightly when at rest. In other words the inside member i6 slightly larger than the bore of the outside member in which it is to be received. The members are thus a tight or a push fit and force must be exerted to insert one inside the other. The resulting radial pressure between the members when assembled ensures that suitable radial pressure is exerted on the ends of the op-tical fibers when received in the grooves, thus pressing them against the rigid member and hence ensuring their alignment.
~ More generally, the ~roove-carrying surface and th~
polished sur~ace of the rigid member may be any two homologous or tangential surfaces suitable for exerting the required mutual pressure on each other by co-operation between their respective shapes. ~;io further suitable examples are shown in Figures 20 and 21 where the apparatus is sihown in cross section~ In both of these cases the rigid member is on the outside~ It is referenced 60~ in Figure 20 ànd 708 in Figure 17 ~1 ~J4~
210 In both cases it is in the form of a rigid sleeve of circular cross section. Inside there is a support of soft material made up from a plurality of parts. In Figure 20 these parts co~prise three rods of equal di~eter (at least in the middle of the apparatus adjacent the grooves 5). The outside contour defined by the set of three rods 604A to 604~ defines the groove-carrying surface 640. Thus three grooves are defined between adjacent rods and the inside surface of the rigid tube. Three optical fiber ends 11A to 11C are shown lodged in the grooves.
Figure 21 sho~Js a similar configuration, except that the support of soft material comprises six rods of equal diameter regularly placed around a seventh, central rod. ~he six outer rods are referenced 704A to 704F, and the central rod is referenced 704G. The outer periphery of the rods defines a groove-carrying surface 740 having six grooves in which six fiber ends 1lA to 11~ are lodged.
~ len the rigid member is on the outside, it is preferably made of glass or other transparent rigid material. The soft ,20 support or the soft support rods are molded`or machined in a silicone type of elastomer such as silastene as sold by the Rhone-Poulenc company.
When it is on the inside, the rigid member can still be ~ade of glass, but it could alternatively be made of any other rigid material, metal or otherwise. When the soft groove support material is on the outside7 it may be made of one of the above-mentioned elastomers, or of any other suitable synthetic material of comparable mechanical properties which is also transparent in at least a portion of -the visible spec-trum '30 in order to facilitate checking that the ends of the fibers are indeed in contact.
In order to facilitate making connections and checking connec-tions in accordance with the invention, it i3 advant~Jeous to improve the visibility of the'optical fibers through the , plate or tube of glass. It has been observed -that the desired result can be obtained by coloring the last few centimeters of the fibers very slightly by means of a felt tip marker pen such as Onyx Marker (Registered Trade Mark). ~he deposit of ink on the fiber is thus very thin, strongly adherent, highly ~isible, and ha~ no effect on fiber centeringO The plane end faces are preferably cleaved after the ends of the fibers have been 5 marked with ink.
Figures 22 and 23 show an improved version of the apparatus shown in Figures 1 and 2.
The improvement relates essentially to the manner in which the optical fibers are clamped beyond the ends OI the groove.
At each end of the base plate 31 of the supporting frame there are two upstanding clips 201 and 202 having hook means near to their tops. A block OI soft material 217 such as elastomer bears axially against the clips 201 and 202. The material should be one which adheres better to the optical 15 fibers than does the material of the groove 5.
~ he end of the optical fiber 1 is passed through a protective sleeve 210, and its stripped end portion is inserted into the ~roove until is comes nearly into contact Wit]1 the end of the other optical ~Eiber (which is supposed to have been 20 previously inserted and clamped by the clamp 225 at the other end of the apparatus). There is no need at this sta~e to ensure intimate contact between the end faces of the two optical fibers.
The protective sleeve 210 is placed so tha-t only about 25 hal~ the length of the elastomer block 217 is in contact with the optical fiber 1.
A cover 215 is pivoted to the sides of the frame 3. At i-ts end distant from the pivot, the cover 215 houses a second ela~tomer block 218 similar to the block 217. The en-~ of the 30 cover has a tab 219 which projects a~ially between the clips 201 and 202 when the cover is closed, which clips then en~age the cover to keep it closed.
In a completely unexpected manner it has been observed that when the elastomer blocks 217 and 218 are pressed a~ainst 35 e~ch other, the optical fiber 1 is automatically urged into the groove 5 so as to come in-to contact with the Iiber 2 which is already there~
~z~ ~ B24 This particularly simple arrangement leads to very safe and reliable optical fiber interconnection.
~ he half way position of the protective sleeve 210 seems to contribute to obtaining the axial thrust towards the groove 5. However, experir~ents have been performed in the absence of a sleeve. The optical fiber is still urg~d towards the groove 5, but in a less marked manner. ~he Applicant is currently of the opinion that what is happening is this: The end of the block 217 bears against the clips 201 and 202. When the matching block 218 presses down on the block 217 the blocks are compress~d. ~he only direction in which the block 217 is free to expand is towards the groove 5. Thus i-t expands in that direction taking the optical fiber wi-th it. ~Ihen a sleeve 210 is used, it appears to be unnecessary for -the block 217 to bear against the clips 201 and 202.
~ inally7 it appears that the optical fiber 1 does not need to be slightly buckled between the point where it leaves the blocks 217 and 218 and the point where it enters the suppor-t 4.
Although the index matching medium is highly advantageous for ensuring good light transrnission, there are some applications for which it may be omitted.
fiber, or a single multi-fiber cable can be connected to a plurality o~ single fiber cables.
The Applican~ has further observed that the polished portion of the rigid plate or member need not necessarily be plane, and on the contrary it may be curved in shape relative to the axis of the groove or grooves. Preferably, the polished portion of the rigid member has a closed right cross section, which may be circular or substantially circular, or else it may be polygonal or substantially polygonal.
In an advantageous embodiment, the polished portion of the rigid plate and the groove-carrying surface are two geometrically similar surfaces, which are quasi complementary and which overlap slightly in the rest po~sition such that placing one against the other requires thrust to be exerted.
More generally, the groove-carrying surface and the polished portion of the rigid plate may be a pair of homologous and/or tangential surfaces æuitable for exerting said bearing force against one another by co-operation of their respective shapes. The elastic portion may in particular be made in several parts such that its outer contour or envelope defines the groove-carrying surface.
In a first family of embodiments? the elastic portion is inside and the rigid member is outside.
In a second family of embodiments the elastic portion is outside and the rigid member is inside. In this case, the rigid member may be provided wi-th a central channel which is advantageous in some applications.
~mbodiments and of the invention are described by way of example, with reference to the accompanying drawings, in which:
~ igure 1 is a perspective view of apparatus in accordance with the invention for making a single fiber connection 7 however, the apparatus shown can be used as a building block in a modular ~ulti-fiber system, ie. for interconnecting -two se-ts of optical fibers;
Figure 2 is a diagrammatlc plan view of the apparatus shown in Figure l;
.
~ igure 3 reproduces portions o~ Figure 2 to a larger scale to bring out details of its structure;
Figures 4 to 9 are perspective views showing various different shapes of grooJe ~lich can be used in the present invention;
Figure 10 i5 a longitudinal section through the ends o~
two interconnected optical fibers which co operate with one another via an index-matching liquid;
Figure ll is a cross section through a fiber as held in a groove showing the co-operation between a block o~ elas-tic ma-terial an~ a rigid p]ate at the end o-f an optical fiber;
~ igure 12 is a perspective view illustrating a particular shape of composite groove usable in apparatus in accordance with the invention, the groove tapers from an inlet end in order to co-operate with both a stripped end portion of an optical fiber and an adjacent portion which is still in its covering;
Figure 13 is a cross section through a variant apparatus in accordance with the invention in which the portion made of soft material is constituted by a plurality of parts;
~igure 14 is a diagrammatic perspective view of a multi-~iber connection apparatus in accordance with the invention;
Figure 15 is a diagrammatic perspective view of the outside of an optical fiber cable interconnection housing enclosing apparatus in accordance with the present inven-tion;
~igure 1~ is a perspec-tive view o~ apparatus in accordance with the invention of circular cross section and with the rigid member on the outside;
~igure -17 is a perspective view o~ apparatus in accordance wi-th -the invention O:e circular cross section and with the rigid member on the inside;
Figure 1~ is a perspective view of apparatus in accordance ~ith the inven-tion having a closed polygonal cross section with the rigid member on the outside;
~igure 19 is a perspective view Oe apparatus in accordance with the invention having a closed polygonal cross sec-tion with the rigid member on the inside;
Figures 20 and ~1 are cross section views through apparatuses comparable -to the Figure 16 apparatus, but in which the support of soft material is made o~ up fron a plurality of parts, ~ igure 22 is a perspective view of a variant apparatus in accordance with the invention, t~liS apparatus being fitted with means that make it particularly simple to set up the required axial thrust on the optical fibers, one of the apparatus is shown open while the other end is sho~m closed; and ~igure 23 is a plan view of the Figure 22 apparatus, with the end that is sho~m open in Figure 22 being shown dismantled in Figure 23.
Optical fiber technology makes frequent lse of shapes. In this respect the accompanying dra~;ings are considered to constitute an integral part of the present description for contributing wherever necessary to the definition of the invention and to the sufficiency of the description thereof.
In the figures, reference numeral 1 designates a first optical ~iber and reference numeral 2 designates a second optical ~iber~ Their ends which have been prepared by stripping off a covering are designated 11 and 12 respectively. In most cases the point of contact between the two ends is not shown.
As indicated above, the ends of two optical fibers are initially prepared by stripping off a portion of covering7 and by preparing end faces for connection, which faces are plane, perpendicular to the fiber axes, and have a shiny mirror type of surface. The person skilled in the art can be ~onsidered to know how to strip off the covering from an optical fiber. ~nd faces which are plane, perpendicular, and have a shiny mirror ~ -type sur~ace can be obtained advantageously by applying the teaching of the above-mentioned ~rench patent application number 78 09703~
The method in accordance with the invention makes use of a ~rame which bears an overall reference numeral 3. The frame comprises a base 31, having t1,Jo rising side walls 32 and 33 which retain an optical fiber support generally designated ~ of material which is softer than the fibers and which is 8 ~ 2~
elastically deformable. The support 4 has an upper surface 43 in which there is at least one fiber-guiding groove 5.
The groove comprises a central portion 5 between two end portions 61 and 62 of larger cross section The outside ends of the end portions 61 and 62 are terminated by flared openings 71 and 72. The central portion 5 and the end portions 61 and 62 are geometrically cylindrical or prismatic in shape, ie.
- they are of constant cross section~ with the central portion having a smaller cross section than the end portions, while the flared openings are frusto conical or pyramidal in shape, and in general have a cross sec-tion of the same shape as the adjacent end portion of the groove.
A polisned rigid plate 8 is kept bearing against the surface 40 of the support ~. In the embodiment shown in Figure 1, the polished rigid plate is held in place by inwardly directed hook-shaped flanges 34 and 35 running along the top edges of the side walls 32 and 33 of the frame 3. ~he support of soft mRterial 4 is thus compressed around four sides by the frame 3 and the rigid plate 8.
The previously prepared ends 11 and 12 of the two optical fibers 1 and 2 wnich terminate in end faces 12 and 22 are - inserted into opposite ends of the groove 5 and light thrust is maintained on each of them to ensure intimate end-to-end contact of their end faces inside the groove. The fact that the plate 8 bears down on the surface 40 of the support 4 means that the ends of the fibers are subjected to a compressive action ~hich gives rise to an opposing radial reaction on the ends of the fibers by the walls (51, 52) of -the groove, thereby aligning the fibers (see ~igure 11).
The fibers are preferably inserted into the apparatus in sequence. In which case the fibers are connected as follows:
1) The end face 12 of a first one of the fibers (in this case the fiber 1) is brought to substantially the middle of the groove 5 as shown in Figure 3.
2) The fiber 1 is fixed relative -to the support. As an example of a suitable means for fixing the fiber, Figure 1 shows a fiber clamp comprising spring jaws 15 having a base ~J~
plate 16 ixed -to the base 31 of the frame 3 and two jaw plates 17 of soft material which are pressed together by the ~spring clamp and be-tween ~hich the optical fiber is held.
3) The end face 22 of the second optical fiber 2 is then moved along -the groove 5 to come into contact with the end face 12 of the first optical fiber 1 (see ~igure 3).
4) The second optical fiber 2 is likewise fixed relative to the support by a second spring clamp 25 which is fixed via its base plate 26 to the other el1d of the base plate 31 of the frame 3~ As before, the clamp uses two jaw plates 27 of soft material for actual clamping contact with the fiber.
It is advantageous to keep -the fibers slightly buckled during each of the above steps, thereby ensuring axial thrust on each of the fibers towards the other fiber. A permanent axial thrust can thus be set up which ~1ill ensure that intimate contact is maintained over long periods of time between the end faces of the fibers. The slight buckling may be obtained by having clamps 15 and 25 ~hich are slightly off-axis relative to the groove 5, or else by having clamps which are on axis but with slightly too long a portion of fiber between each clamp and the point of contact between the end faces. ~he position of the clamps may be axially adjustable to ensure a desired degree of buckling.
~he groove 5 is preferably filled with index matching liquid before the fibers are inserted therein in ordér to improve light transmission between the fibers (see Figure 10).
It has been observed, that in addition -to this known effect of index matching li~uid, the presence of the liquid in the groove also has the effect of automatically cleaning the zone between the end faces 12 and 22 because of the piston effect of inserting the fibers in the groove 5 along axes 19 and 29.
Excess liquid is expelled in particular along the bottom notch 53 of -the groove, and also a]ong the upper passa~es 54 and 55 next to -the rigid plate 8 (see ~igure 11).
In practice it is useful to apply light to the fibers to - be connected. This can be done either via their respective other ends, or else, and preferably, by injecting light through .. . .. . _ _ 1 o ~',2fL'~
the sides of the fibers through their coverings. ~he injected light may be pulsed particularly if it is injected through the sides. This has the effect of causing a point of light to appear at each of the fiber end faces 12 and 22. As the fibers approach each other the points of light can be seen to get closer together. Intimate end-to-end contact between the end faces 12 and 22 can be considered to have been obtained when the points of light become highly attenuated or practically disappear.
This indication of good contact by means of injected light naturally requires the rigld plate 8 to be transparent.
It is indicated above that the fibers have their covering stripped off over an end portion and that their end faces are specially prepared to obtain the good optical characteristics for interconnection. In ~igures 1 to 3 the stripped end portions of the fibers are referenced 11 and 12 respectively.
These are the portions of the fibers which are inserted in the central portion 5 of the groove.
As a result an optical fiber connection apparatus is obtained in which a support 4 made of soft elastically deformable material has a straight groove 5 in at least one surface 40 thereof and suitable for receiving in end-to-end contact the ends 11 and 12 respectively of two optical fibers 1 and 2 to be connected 9 each of the fibers having an end face 12 or 22 respectively which is perpendicular to the axis of the fiber and which has a shiny mirror type of surface. In accordance with the present invention the member which keeps the fibers pressed against said surface of the support is a rigid polished plate 8 which applies the said compressive action with the advanta~es that result therefrom.
3 It is hiehly adv mtc~eouC; to have enlarged grooves 61 and 62 at each e1d of the central portion 5 for receiving op-tical ~iber from whicl1 the covering has not been stripped. These enlarged portions 61 and 62 are best seen in Figures 2 3 and 12. Finally each of the grooves has a flared inlet portion.
Figure 2 shows both flared inlet portions 71 and 72 .rhile Figures 3 and 12 show the inlet portion 71 to a larger scale.
In the embodi1nent of the invention described above, the support of soft material 4 is made from a single block of material.
~ he groove 5 per se, ie. the central portion thereof, may have various shapes.
~ igure 4 shows a first shape in which the groove 5 has a Y-shaped cross section with two sides 51 and 52 and an apex 53.
The sides 51 and 52 are symmetrically disposed about an axis 54 which is perpendicular to the surface 40 of the support block.
With reference to Figure 12, it can be seen how such a groove 5 of symmetrical trian~ular section can run into an adjacen-t length of groove 61 which ls of larger cross section so as to be able to receive a fiber still inside its covering without being too tight a fit. In particular there is a progressive transition from the larger section portion 61 to the smaller section portion 5. Finally the larger groove 61 termina-tes in a flared portion 71 having sides 74 and 75 which remain symmetrical about a plane perpendicular to the surface 40 and which lead to an end face 41 of the support 4~
o Figure 13 shows a variant emboAiment of the present invention in which the support of soft ma-terial is made up from a plurality of parts. A rigid bottom pla-te 10~ has a plurality of rods of soft material 104 fixed in parallel thereon in mutual contact to define a plurality of grooves 5 between adjacent rods 104. ~he rods 104 may be glued -to the bot-tom plate 103, for example. A rigid plate of polished ~lass 108 is pressed against -the otner side of the rods 104 in such a manner tha-t they are sandwiched between the plates 103 and 108, which are themselves held together by channel section side clamps 133 and 134. The resulting groovns 5 are ~enerally Y shaped, bu-t with curved sides that are convex as seen from inside the grooves. Many other shapes of groove 5 could be produced in this manner by using rods of suitable shapes.
Examples of other shapes of groove are now described with reference to Figures 5 to 9. These shapes may be formed in a single block of soft material or else they may be formed by juxtaposin~ two suitably- shaped rods, as shown in ~igure 13.
1 2 ~L~
Figure 5 shows a piece of soft material 4 having a groove cf rectang,llar or square cross section. It has two vertical sides 151 and 153 and a hori~ontal floor 152.
Figure 6 sho~"s a groove 5 has a cross section which is in 5 four segments 251, 252, 254, and 255. ~he bottom of the groove is referenced 25~.
~he groove shape shown in ~igure 6 is symmetrical about a plane perpendicular to the surface 40, but asymrnetrical shapes are also possible. Figure 9 shows such a shape. In this embodiment, the r~roove 5 has a cross section defined by a sloping side 551 and a vertical side 552 with the bottom of the groove being referenced 550. The vertical side 552 coincides with the plane 554 perpendicular to the top surface 40 of the support of soft material 4.
In the rernaining shapes that are de6cribed below, the groove cross section is defined by one or more curved segments, ~hich may by combined with rectilinear segments.
~igure 7 shows a ~roove 5 having a semicircular cross section like guttering 350, with the edges of the guttering 351 and 352 meeting the top sur-face 40 of the support 4.
In contrast, Figure 8 shows a groove 5 of generally V-shaped cross section made up of two quarter circles 451 and 452 meeting at a cusp at the bottom of the groove.
It is recalled that apparatuses described in previously known documents make use of two part~s w11ich are both made of soft material and placed on either si1e of the ends of the fibers to be joined, relying on the elas-ticity of the two parts to bring the fibers into adsqla-te alignment.
In a manner which is a priori unexpected, it has been observed that the use of a por-tion of soft material in conjunction with a rigid pla-te on the other æide of the fiber provides suEficient alignment of the fibers to be connected to ensure good optical interconnection between -the fibers. Initial tests by the Applicant have shown that attenuation of about one tenth of a decibel is to be ohtained at 511,-'h an interconnection, which thus constitutes an excellent optical connection.
2~
It has been observed that the method and apparatus in accordance with the invention function well even if the fibers to be interconnected are of slightly different diameters, due to manufacturing tolerances for e~ample (such as fibers taken from different batches or from di~erent sllppliers). The present invention is also remarkable for its simplicity and for the way it is well adapted to the fra~ility and small size of the fibers.
In a particular embodiment, the top plate ~ is a plate of glass of suitable thickness to ensure its rigidit~. It appears that a thickness of one millimeter is adequate. lhe support of soft material, or the rods of soft material as the case may be, are molded or machined in a silicone elastomer type of material such as silastene which is sold by the Rhone-Poulenc company.
~5 lhe frame may be made of metal. Finally, the in~1ex matching liquid is preferably a silicone oil such Dow Corning's liquid N SI 200 (viscosity 50 cp).
A more complex embodiment of the invention is now described with reference to Figures 14 and 15~
In this embodiment, -the support of soft material is referenced 104 and has a plurality of grooves 105. In order to simplify the drawing, the grooves 105 are shown as being of constant sec-tion in Figure 14, whereas, in practice, they are preferably in the form of a central portion of small æection with two end portions of larger section as described above, eg.
with reference to Figure 12. The support 104 is mounted on a base 103 having lugs 138 and 139 ~or fixing to an underlying surface (not shown). The ends of -the base 103 have upwardly directed risers 132 and 133 which fold over at -the top to 3 provide inwardly direc-ted flanges 134 and 135 for holding down a plate of glass 108 pressed a~ainst the grooved top surface of the support of soft material 104 as in the above-described embodiment. The uncovered faces of the support block are referenced 141 and 142. In Figure 14, onl~ one optical fiber connection is sho~m between fibers 101 and 102 which meet end-to-end in the middle of one of the grooves 105.
Two clamping strips are 115 and 125 are dlsposed on ei-ther side of the su~port block 104, all~ eae~l of them has its own fixing lugs 116 or 126 for fixing to the same sur~ace (not shown) as the base plate 103 is fixed. The clarnpin~ strip3 nave tra,ls~e~ ,assa~es for individual fibers in the non-stripped state (only two fibers 101 and 102 are shown). ~ac'n fiber is lodged-in its own elastomer sleeve (not shown) which is located in a channel 118 and which is held in place by a screw 119. ~he elastomer serves to prevent microcurves or even breaks in the optical fibers, which would impair light transmission. It can be seen -that the two optical fibers shown are slightly buckled as before.
In spite of only one connection being shown explicitly, it is clear that the apparatus sho-~1 in Figure 14 can be used for interconnecting in pairs a plurality of optical fibers from two different sets of fibers each including ten different fibers.
With reference to Figure 15, a protective housing 100 encloses apparatus of the type shown in Figure 14. The housing 100 has passages suitable for passing individual optical fibers or for passing an optical fiber cable in sealed manner to the inside of the housing. Although it is possible to interconnect two ten-fiber cables to each other~ the housing shown in ~ ure 15 represents a slightly different arrangement where ten single fiber cables 101A to 101J enter the housing through one wall, whereas a single ten-fiber cable 102 leaves the housing through an opposite wallO
The flxing lugs 138, 139, 116 and 126 shown in ~igure 14 are naturally fixed to another wall o~ the housing 100.
Other embodiments of the invention are now described in which either the rigid plate, or the soft support, or both are no-t plane mernbers. Nonetheless, the various groove cross sections described above can s-till be freely selected.
~ikewise, the following features which have already been described in relation to a plane embodiment can still apply:
1) The optical fibers are caused to buckle slightly on entering the apparatus to ensure suitable end-to-end contact pressure.
2) Index matching liquid is used, and the same piston effect takes place.
1 5 ~ 2~
~) Light can be used as a guide to determinin~ when good contact has been obtained.
~) ~he outside member of the apparatus should therefore be transparent over at least a portion of the visible spectr-um so that the contact determining points of light can be seen.
5) Each multi-fiber apparatus shown could readily be adapted to single fiber connection where required.
~ inally, it is ass~ned that the pairs of fiber ends to be interconnected have been suitably prepared to obtain end faces which are plane, perpendicular to the -fiber axes, and which have a shiny mirror type of r,urrace. The protective coverings are preferably stripped off over a suitable length.
Figure 16 shows a rigid member 208 in the for~ of a cylindrical glass tube having a cross section which is in -the form of a circular ring. A support of soft material 204 is a push fit inside the glass tube 208. The periphery of the support has seven~equi-spaced grooves such that the periphery of the support member 2Q4 constitutes the groove-carrying surface 240. Only one of the grooves is shown in detail. As mentioned above, the apparatus could be made to have only a - single groove.
Figure 17 shows a reciprocal configuration in which the rigid member is in the form of a solid cylinder 308 inside the - support 304 which is in the form of a tight-~itting sleeve of cof-t material disposed around the rigid member. The cross section of the support is a circular ring and it has seven longitudinally extending grooves running along its inside wall.
Only one of the grooves is shown in full, and indeed -there need only be one such groove. The groove-carrying surface is referenced ~40.
Instead of bein~ of truly circular sross section, as shown in Figures 16 and 17, the apparatus can be made to have a poly-gonal cross sec-tion, which may be regular or irregular.
Figures 18 and 19 show two fur-ther embodimen-ts generally equivalent to those of Figurss 16 and 17 respectively, except that the rnembers are of rectangular cross section. The person skilled in the art will understand tha-t various other shapes can readily be used~ for example, the edges of the polygonal shapes could be rounded or chamfered.
In Figure 18, as in ~igure 16, the rigid member 408 is on the outside. The support of soft material 404 is inside the rigid member and has three grooves running along its upper plane surface (as disposed in the figure). ~he closed groove-carrying surface is referenced 440 in this case. ~hree fibers 1A, 1~, and 1C arrive at one end of the apparatus, while -three other fibers 2A, 2~, and 2C arrive at the other endO ~aking the fibers 1A and 2A by way of example7 their ends 11A and 21A
meet substanti~lly at the middle of the cen-tral groove 5~
Similarly ~igure 19 shows a reciprocal configuration in which the rigid member 50~ is insiae and is of rectangular cross section. The suppor-t 504 of soft material is on the outside and its inside surface 540 (ie. the surface including all four inside planes of the support 504) includes three longitudinally extending grooves in the top plane thereof.
In the embodi~ents described above, the touching portions of the rigid polished plate and the groove-carrying surface are geometrically similar, are substantially complementary, and are so dimensionea as to overlap slightly when at rest. In other words the inside member i6 slightly larger than the bore of the outside member in which it is to be received. The members are thus a tight or a push fit and force must be exerted to insert one inside the other. The resulting radial pressure between the members when assembled ensures that suitable radial pressure is exerted on the ends of the op-tical fibers when received in the grooves, thus pressing them against the rigid member and hence ensuring their alignment.
~ More generally, the ~roove-carrying surface and th~
polished sur~ace of the rigid member may be any two homologous or tangential surfaces suitable for exerting the required mutual pressure on each other by co-operation between their respective shapes. ~;io further suitable examples are shown in Figures 20 and 21 where the apparatus is sihown in cross section~ In both of these cases the rigid member is on the outside~ It is referenced 60~ in Figure 20 ànd 708 in Figure 17 ~1 ~J4~
210 In both cases it is in the form of a rigid sleeve of circular cross section. Inside there is a support of soft material made up from a plurality of parts. In Figure 20 these parts co~prise three rods of equal di~eter (at least in the middle of the apparatus adjacent the grooves 5). The outside contour defined by the set of three rods 604A to 604~ defines the groove-carrying surface 640. Thus three grooves are defined between adjacent rods and the inside surface of the rigid tube. Three optical fiber ends 11A to 11C are shown lodged in the grooves.
Figure 21 sho~Js a similar configuration, except that the support of soft material comprises six rods of equal diameter regularly placed around a seventh, central rod. ~he six outer rods are referenced 704A to 704F, and the central rod is referenced 704G. The outer periphery of the rods defines a groove-carrying surface 740 having six grooves in which six fiber ends 1lA to 11~ are lodged.
~ len the rigid member is on the outside, it is preferably made of glass or other transparent rigid material. The soft ,20 support or the soft support rods are molded`or machined in a silicone type of elastomer such as silastene as sold by the Rhone-Poulenc company.
When it is on the inside, the rigid member can still be ~ade of glass, but it could alternatively be made of any other rigid material, metal or otherwise. When the soft groove support material is on the outside7 it may be made of one of the above-mentioned elastomers, or of any other suitable synthetic material of comparable mechanical properties which is also transparent in at least a portion of -the visible spec-trum '30 in order to facilitate checking that the ends of the fibers are indeed in contact.
In order to facilitate making connections and checking connec-tions in accordance with the invention, it i3 advant~Jeous to improve the visibility of the'optical fibers through the , plate or tube of glass. It has been observed -that the desired result can be obtained by coloring the last few centimeters of the fibers very slightly by means of a felt tip marker pen such as Onyx Marker (Registered Trade Mark). ~he deposit of ink on the fiber is thus very thin, strongly adherent, highly ~isible, and ha~ no effect on fiber centeringO The plane end faces are preferably cleaved after the ends of the fibers have been 5 marked with ink.
Figures 22 and 23 show an improved version of the apparatus shown in Figures 1 and 2.
The improvement relates essentially to the manner in which the optical fibers are clamped beyond the ends OI the groove.
At each end of the base plate 31 of the supporting frame there are two upstanding clips 201 and 202 having hook means near to their tops. A block OI soft material 217 such as elastomer bears axially against the clips 201 and 202. The material should be one which adheres better to the optical 15 fibers than does the material of the groove 5.
~ he end of the optical fiber 1 is passed through a protective sleeve 210, and its stripped end portion is inserted into the ~roove until is comes nearly into contact Wit]1 the end of the other optical ~Eiber (which is supposed to have been 20 previously inserted and clamped by the clamp 225 at the other end of the apparatus). There is no need at this sta~e to ensure intimate contact between the end faces of the two optical fibers.
The protective sleeve 210 is placed so tha-t only about 25 hal~ the length of the elastomer block 217 is in contact with the optical fiber 1.
A cover 215 is pivoted to the sides of the frame 3. At i-ts end distant from the pivot, the cover 215 houses a second ela~tomer block 218 similar to the block 217. The en-~ of the 30 cover has a tab 219 which projects a~ially between the clips 201 and 202 when the cover is closed, which clips then en~age the cover to keep it closed.
In a completely unexpected manner it has been observed that when the elastomer blocks 217 and 218 are pressed a~ainst 35 e~ch other, the optical fiber 1 is automatically urged into the groove 5 so as to come in-to contact with the Iiber 2 which is already there~
~z~ ~ B24 This particularly simple arrangement leads to very safe and reliable optical fiber interconnection.
~ he half way position of the protective sleeve 210 seems to contribute to obtaining the axial thrust towards the groove 5. However, experir~ents have been performed in the absence of a sleeve. The optical fiber is still urg~d towards the groove 5, but in a less marked manner. ~he Applicant is currently of the opinion that what is happening is this: The end of the block 217 bears against the clips 201 and 202. When the matching block 218 presses down on the block 217 the blocks are compress~d. ~he only direction in which the block 217 is free to expand is towards the groove 5. Thus i-t expands in that direction taking the optical fiber wi-th it. ~Ihen a sleeve 210 is used, it appears to be unnecessary for -the block 217 to bear against the clips 201 and 202.
~ inally7 it appears that the optical fiber 1 does not need to be slightly buckled between the point where it leaves the blocks 217 and 218 and the point where it enters the suppor-t 4.
Although the index matching medium is highly advantageous for ensuring good light transrnission, there are some applications for which it may be omitted.
Claims (34)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1/ A method of connecting optical fibers, the method including a preparatory step of:
a) preparing the ends of at least two optical fibers for connection;
and comprising the improvement of the following step in which:
b) the ends of at least two fibers to be connected are inserted end-to-end in a groove provided in the surface of a support which, at least at said surface, is made of a material that is softer than the fibers and which is elastically deformable; and the fibers are lightly urged against one another to ensure intimate contact between their end faces; at the same time a polished rigid member is maintained bearing against said support surface thereby applying pressure to said fibers giving rise to radial reaction from the wall of the groove against the fibers and thus ensuring that the fibers are in alignment.
a) preparing the ends of at least two optical fibers for connection;
and comprising the improvement of the following step in which:
b) the ends of at least two fibers to be connected are inserted end-to-end in a groove provided in the surface of a support which, at least at said surface, is made of a material that is softer than the fibers and which is elastically deformable; and the fibers are lightly urged against one another to ensure intimate contact between their end faces; at the same time a polished rigid member is maintained bearing against said support surface thereby applying pressure to said fibers giving rise to radial reaction from the wall of the groove against the fibers and thus ensuring that the fibers are in alignment.
2/ A method according to claim 19 wherein step b) is performed as follows:
b1) the end face of a first one of the fibers is brought to substantially half way along the groove;
b2) the first fiber is fixed relative to the support;
b3) the end face of the second fiber is brought into contact inside the groove with the end face of the first fiber; and b4) the second fiber is also fixed relative to the support, at the opposite end thereof.
b1) the end face of a first one of the fibers is brought to substantially half way along the groove;
b2) the first fiber is fixed relative to the support;
b3) the end face of the second fiber is brought into contact inside the groove with the end face of the first fiber; and b4) the second fiber is also fixed relative to the support, at the opposite end thereof.
3/ A method according to claim 2, wherein each of the fixing steps b2 and by is performed in such a manner as to urge the fibers towards each other, thereby maintaining close end-to-end contact between the fibers over a period of time by virtue of the permanent axial force thus exerted.
4/ A method according to claim 1, wherein the groove is initially filled with an index matching liquid, thereby not only improving light transmission between the fibers, but also automatically cleaning the zone between the two fiber end faces by virtue of the piston effect exerted by said end faces as the fibers are moved along the groove while being inserted therein.
5/ A method according to claim 1, wherein said rigid member is transparent.
6/ A method according to claim 5, wherein step b further includes applying light radiation to the two fibers to be connected, causing a point of light to appear at each fiber end face, said end faces being considered to be in intimate contact when said points of light are attenuated or practically disappear.
7/ A method according to claim 5, wherein the sides of the prepared end portions of the fibers are colored.
8/ Apparatus for connecting optical fibers, the apparatus comprising firstly a support having at least one surface which is made of soft, elastically deformable material and which includes a groove suitable for receiving the ends of two optical fibers to be connected in end-to-end contact, and secondly a member which is kept bearing against the support surface and the ends of the optical fibers, the improvement wherein said member comprises a polished rigid part such that keeping it bearing against the said support surface exerts a compression action on the said ends of the fibers, giving rise to radial reaction from the wall of the groove against the ends of the fibers, and thus ensuring that the fibers are aligned.
9/ Apparatus according to claim 8, wherein said support of soft material is mounted on a rigid frame, and wherein the frame includes hook-shaped members placed to hold said rigid member pressed against the soft support against the elastic reaction thereof, thereby keeping the rigid member bearing against said support surface.
10/ Apparatus according to claim 8, wherein the support of soft material is in the form of a block.
11/ Apparatus according to claim 8, wherein the support of soft material comprises a plurality of adjacent parts.
12/ Apparatus according to claim 8, wherein said rigid member is a transparent plate.
13/ Apparatus according to claim 12, wherein said transparent plate is made of glass.
14/ Apparatus according to claim 8, including two clamps, one on either side of the support, for fixing the fibers relative to the support, in such a manner as to ensure that the fibers are urged towards each other, so that the permanent axial thrust thus exerted on the fibers ensures that close contact is maintained over time between the end faces of' the fibers in the groove.
15/ Apparatus according to claim 8, wherein said groove has a cross section made up of a plurality of line segments.
16/ Apparatus according to claim 15, wherein said groove has a V-shaped cross section.
17/ Apparatus according to claim 8, wherein said groove has a cross section made up of one or more curved line segments.
18/ Apparatus according to claim 8, wherein said groove is symmetrical about a plane perpendicular to said surface of soft material.
19/ Apparatus according to claim 8, wherein each end of said groove includes a portion of greater cross section suitable for receiving an optical fiber inside its covering.
20/ Apparatus according to claim 8, wherein each end of said groove is flared.
21/ Apparatus according to claim 8, including a plurality of rectilinear grooves having substantially parallel axes, thereby enabling a plurality of optical fibers belong to two different sets of fibers to be interconnected end-to-end in pairs.
22/ Apparatus for connecting optical fibers according to claim 8, the apparatus comprising firstly a support which is made of soft, elastically deformable material and which defines a groove-carrying surface having one or more grooves suitable for receiving the ends of two optical fibers to be connected in end-to-end contact, and secondly a rigid member having a polished surface which is kept bearing against the groove-carrying surface and the ends of the optical fibers giving rise to radial reaction from the wall of the groove(s) against the ends of the fibers, thus ensuring that the fibers are aligned 7 the improvement, wherein the polished surface of the rigid member is curved about the axis of the groove(s).
23/ Apparatus according to claim 22, wherein the polished portion of the rigid member has a closed cross section.
24/ Apparatus according to claim 23, wherein the polished portion of the rigid member has a circular or substantially circular cross section.
25/ Apparatus according to claim 23, wherein the polished portion of the rigid member has a polygonal or substantially polygonal cross section,
26/ Apparatus according to claim 22, wherein the polished portion of the rigid plate and the groove-carrying surface are two geometrically similar surfaces, which are quasi complementary and which overlap slightly in the rest position such that placing one against the other requires thrust to be exerted.
27/ Apparatus according to claim 22, wherein the groove-carrying surface and the polished portion of the rigid plate are a pair of homologous and/or tangential surfaces suitable for exerting said bearing force against one another by co-operation of their respective shapes.
28/ Apparatus according to claim 22, wherein the elastic portion is made from a plurality of parts such that its outer contour or envelope defines the groove-carrying surface.
29/ Apparatus according to claim 22, wherein the elastic portion is inside and the rigid member is outside.
30/ Apparatus according to claim 22, wherein the elastic portion is outside and the rigid member is inside.
31/ Apparatus according to claim 22, wherein the outside member is at least partially transparent.
32/ Apparatus according to claim 22, wherein the rigid member is made of glass.
33/ Apparatus according to claim 14, wherein each clamp comprises a block of soft material on the support side of the clamp, said block of clamp soft material abutting axially against a stop on the opposite side to the support, each clamp further comprising a hinged closure member including a second block of similar soft material which bears against the said block in such a manner as to urge a fiber running between said blocks towards the groove in the support.
34/ Apparatus according to claim 33, whereirlwherein the portion of fiber running between said clamp blocks is partially lodged in a protective tube or sleeve.
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR8304082 | 1983-03-11 | ||
| FR8304082A FR2542458B1 (en) | 1983-03-11 | 1983-03-11 | METHOD AND DEVICE FOR JOINING OPTICAL FIBERS |
| FR8306499A FR2544876B2 (en) | 1983-04-20 | 1983-04-20 | IMPROVED DEVICES FOR CONNECTING OPTICAL FIBERS |
| FR8306499 | 1983-04-20 |
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| Publication Number | Publication Date |
|---|---|
| CA1241824A true CA1241824A (en) | 1988-09-13 |
Family
ID=26223330
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000449347A Expired CA1241824A (en) | 1983-03-11 | 1984-03-12 | Method and apparatus for connecting optical fibers |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US4629284A (en) |
| EP (1) | EP0122169B1 (en) |
| CA (1) | CA1241824A (en) |
| DE (1) | DE3482500D1 (en) |
| ES (1) | ES530378A0 (en) |
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| GB1430979A (en) * | 1973-12-13 | 1976-04-07 | Post Office | Dielectric optical waveguides |
| CA1053491A (en) * | 1974-08-19 | 1979-05-01 | Robert M. Hawk | Optical waveguide connector |
| DE2456552C2 (en) * | 1974-11-29 | 1983-12-01 | Siemens AG, 1000 Berlin und 8000 München | Connection of two fiber optic bundles and method of making the connection |
| DE2518319C2 (en) * | 1975-04-24 | 1981-11-05 | Siemens AG, 1000 Berlin und 8000 München | Detachable splice connection for fiber optic cables |
| DE2522740C3 (en) * | 1975-05-22 | 1981-05-14 | Siemens AG, 1000 Berlin und 8000 München | Device for connecting an incoming fiber optic cable with a continuing and method for producing the device |
| US4102561A (en) * | 1975-07-02 | 1978-07-25 | Corning Glass Works | Optical waveguide connector |
| JPS5282343A (en) * | 1975-12-29 | 1977-07-09 | Sumitomo Electric Ind Ltd | Method and device for connecting optical fibers |
| DE2611658C3 (en) * | 1976-03-19 | 1981-12-17 | Licentia Patent-Verwaltungs-Gmbh, 6000 Frankfurt | Adjustment device for optical fibers |
| US4172746A (en) * | 1976-03-31 | 1979-10-30 | Noane Georges Le | Method for on-site connection of cables with optical fibres |
| US4046454A (en) * | 1976-05-18 | 1977-09-06 | Bell Telephone Laboratories, Incorporated | Optical fiber connector |
| JPS5310445A (en) * | 1976-07-15 | 1978-01-30 | Furukawa Electric Co Ltd:The | Aligned joint of optical fibers |
| FR2360896A1 (en) * | 1976-08-03 | 1978-03-03 | Lignes Telegraph Telephon | CONNECTION STRUCTURE FOR OPTICAL FIBER CABLE |
| US4186997A (en) * | 1977-02-14 | 1980-02-05 | Amp Incorporated | Overlap type waveguide connector assembly and method |
| JPS5434251A (en) * | 1977-08-22 | 1979-03-13 | Nippon Telegr & Teleph Corp <Ntt> | Multiconnector for optical fibers |
| JPS54106246A (en) * | 1978-02-07 | 1979-08-21 | Nippon Telegr & Teleph Corp <Ntt> | Connectors for optical fibers |
| US4184741A (en) * | 1978-02-27 | 1980-01-22 | Corning Glass Works | Filament-to-device coupler |
| FR2443075A1 (en) * | 1978-08-29 | 1980-06-27 | Comp Generale Electricite | FIBER TO FIBER CONNECTOR PLUG WITH CONNECTING ELEMENT TO AN OPTICAL CABLE |
| GB2046466B (en) * | 1979-01-24 | 1983-02-16 | Bicc Ltd | Joining optical fibres using magnifier |
| US4257674A (en) * | 1979-04-23 | 1981-03-24 | Gte Products Corporation | Elastomeric fiber optic splice |
| US4302267A (en) * | 1980-02-20 | 1981-11-24 | General Dynamics, Pomona Division | Optical fiber mating apparatus and method |
| JPS5776509A (en) * | 1980-10-30 | 1982-05-13 | Nippon Sheet Glass Co Ltd | Optical fiber-lens coupler and its manufacture |
| JPS584110A (en) * | 1981-06-30 | 1983-01-11 | Kyocera Corp | Multiconnector for optical fiber |
-
1984
- 1984-03-06 EP EP84400448A patent/EP0122169B1/en not_active Expired - Lifetime
- 1984-03-06 DE DE8484400448T patent/DE3482500D1/en not_active Expired - Fee Related
- 1984-03-06 US US06/586,748 patent/US4629284A/en not_active Expired - Fee Related
- 1984-03-08 ES ES530378A patent/ES530378A0/en active Granted
- 1984-03-12 CA CA000449347A patent/CA1241824A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| ES8500662A1 (en) | 1984-11-01 |
| ES530378A0 (en) | 1984-11-01 |
| EP0122169A2 (en) | 1984-10-17 |
| EP0122169B1 (en) | 1990-06-13 |
| EP0122169A3 (en) | 1987-08-19 |
| US4629284A (en) | 1986-12-16 |
| DE3482500D1 (en) | 1990-07-19 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |