WO2001053867A1

WO2001053867A1 - Optical fiber connector cleaning apparatus

Info

Publication number: WO2001053867A1
Application number: PCT/US2000/013482
Authority: WO
Inventors: John W. Fulmer
Original assignee: 3M Innovative Properties Company
Priority date: 2000-01-18
Filing date: 2000-05-16
Publication date: 2001-07-26
Also published as: AU2000250216A1

Abstract

A device is provided for cleaning the end face of a bare optical fiber that is retained within a connector plug. The device includes a tray having a cleaning surface and a socket slidably connected to the tray so that the socket is slidable therein. The socket has an opening sized to receive the connector plug. A projection with at least one fiber alignment groove is located in the socket to receive a terminal portion of the optical fiber located in the connector plug when the plug is inserted in the socket. The groove is positioned with respect to the tray such that the end face of the optical fiber located in the connector plug extends beyond the groove and remains substantially uniformly spaced from, and exposed to, the cleaning surface of the tray when the socket slides in the tray.

Description

OPTICAL FIBER CONNECTOR CLEANING APPARATUS

FIELD OF THE INVENTION

The present invention generally relates to devices for preparing the terminal end of a telecommunications line so as to improve the quality of a connection in the line, and more particularly to a device for cleaning the end face of an optical fiber to be interconnected with another optical fiber or with an optoelectronic component.

0 BACKGROUND

Optical fibers have replaced copper wire as the preferred medium for carrying telecommunications signals. As with copper wire, it is necessary to provide for the interconnection of optical fibers during installation, repair or replacement of the fibers, and to terminate the fibers onto active optical devices. There are generally two kinds of 5 interconnection devices, splices and connectors. The term "splice" usually refers to a device which provides a permanent connection between a pair of optical fibers. The term "connector," by contrast, usually refers to a device that may be engaged and disengaged repeatedly, often with a different plug or receptacle. A connector may also refer to the plug portion of a fiber termination, which is attached to an optical device. Optical devices o include, for example, optical sensors (photoelectric diodes) and light sources (LED's, laser diodes). The termination of an optical fiber may be indirect, i.e., the fiber may be connected to some other (passive) optical device such as a beam splitter or polarizer, before the light beam is directed to the active optical device.

In the fiber optic connector described in U.S. 5,757,997 (Birrell et al.), a plug and 5 receptacle use the spring force supplied by bowing of the plug fiber to maintain a continuous compressive load at the fiber joint located in a fiber-alignment groove. The plug has a holder for securing the plug fiber and a shroud which snaps onto the holder with the plug fiber extending generally straight inside the shroud. The shroud has a slot providing access to the terminal portion of the plug fiber, and a sliding door which o selectively covers the slot. The receptacle includes a housing and another fiber holder for securing the receptacle fiber, and is equipped with a projection, attached to the receptacle fiber holder, which has a fiber-alignment groove. The projection is oriented within the receptacle housing such that, when the plug is inserted into the receptacle, the projection extends through the slot in the shroud at an oblique angle with respect to the plug axis. In this manner, as the plug is inserted, the end of the plug fiber slides into the fiber-alignment groove in the projection and comes into contact with the end face of the receptacle fiber. Continued insertion results in bowing of the plug fiber to achieve the compressive load.

In the connector of the '997 patent, it is incumbent upon the user or craftsperson installing the plug or receptacle to keep the terminal end faces of the fibers as clean as possible so as to minimize losses in light transmission across the connection. Since this design is intended for repeated insertion of a plug into a receptacle, it is possible that the plug fiber ends will become contaminated while the plug is outside of the receptacle. It therefore may become necessary to clean the fibers after they have been affixed to the plug or receptacle housing. When the fibers are originally installed, they are commonly cleaved to yield a fractured end face which may be further polished or beveled, and then cleaned by wiping the end with a lint-free cloth which has been dipped in a liquid solvent such as isopropyl alcohol. This task is difficult to accomplish after installation, since in many designs, such as the plug shown in the '997 patent, the fibers are located within a housing in such a manner that they are difficult to access. The fiber end faces located in the plug shroud of the '997 patent are sometimes cleaned by spraying a liquid solvent onto the plug. Such a cleaning technique, which is exemplified in U.S. 6,006,768 (Cox), is quick and convenient and effectively cleans the shaft and end face of the fiber as well as the interior plug housing. In some circumstances, however, this technique does not remove debris from the fiber end face. For example, debris may be ground into the fiber end face after repeatedly inserting and removing the plug from the receptacle. In these circumstances, a more effective cleaning mechanism is required.

U.S. 5,836,031 (Cox) discloses a device for cleaning the end face of fibers that have been installed in a plug shroud of the type shown in the '997 patent. The device includes a tool body having cleaning media therein, such as a strip of adhesive tape. The tool body has an opening for receiving the plug. Push rods are provided in the tool body, which contact the fibers and urge them towards a cleaning position so that the end faces contact the adhesive tape. Unfortunately, this device does not employ a liquid solvent, which has the benefit of cleaning not only the fiber end face but also the fiber shaft and the interior of the plug housing. Also, contaminants that are firmly bound to the surface of the fiber may remain on the fiber end faces despite the use of an adhesive tape.

U.S. 5,768,738 (Lee), U.S. 5,117,528 (Kanayama et al.), U.S. 5,220,703 (Kanayama et al.), JP 08101326 (Kazuhiro et al.) and JP 08101325 Kazuhiro et al.) disclose various devices for cleaning optical fiber connectors which feature a cassette type cleaner resembling a cassette tape. In these devices, an advancing spool of cleaning material is brought into contact with the surface of the optical fiber. However, these devices are designed for use with an optical fiber connector terminating in a rigid ferrule end surface that is thick relative to the diameter of an optical fiber. Consequently, these devices are not suitable for cleaning the terminal portions of bare optical fibers disposed within a plug, since no provisions are made for controlling the orientation of the bare fibers relative to the cleaning surface or for opening the plug so that the fibers are properly exposed. Moreover, none of the aforementioned devices can be readily adapted to the use of cleaning solvents.

U.S. 5,735,013 (Yaguchi et al.) discloses a cleaning device for bare optical fibers in which the optical fibers are clamped between two cleaning surfaces and then drawn. However, as with several of the devices noted above, no provision is made for the use of liquid solvents in this device, nor is the device provided with means for exposing the bare fibers within a fiber optic plug.

There is thus a need in the art for a device which is capable of cleaning the end faces of a fiber optic cable that is disposed within a plug or housing, and for a method of doing the same. There is also a need in the art for a device and methodology that uses both a liquid solvent and a cleaning media, such as a lint-free cloth, to clean fiber end faces which are otherwise inaccessible within a connector housing. These and other needs are met by the present invention, as hereinafter described. SUMMARY OF THE INVENTION

The present invention relates to a device for cleaning the end face of a bare optical fiber that is retained within a connector plug, and to methods for doing the same. The device includes a tray having a cleaning surface and a socket slidably connected to the tray so that the socket is slidable therein. The socket has an opening sized to receive the connector plug. A projection with at least one fiber alignment groove is located in the socket to receive a terminal portion of the optical fiber located in the connector plug when the plug is inserted in the socket. The groove is positioned with respect to the tray such that the end face of the optical fiber located in the connector plug extends beyond the groove and remains substantially uniformly spaced from, and exposed to, the cleaning surface of the tray when the socket slides in the tray.

In one aspect, the present invention relates to a device of the type described above in which the position of the groove with respect to the tray is such that there exists a space between an end of the groove and the cleaning surface. The space is sufficient to position a cleaning medium therein that contacts both the cleaning surface of the tray and the fiber end face that extends beyond the end of the groove.

In another aspect, the present invention relates to a device of the type described above in which the tray comprises first and second tray portions pivotably connected to one another. The second tray portion defines a bottom of the tray on which the cleaning surface resides.

In still another aspect, the present invention relates to a device of the type described above in which the tray includes sidewalls having slots in which projections of the socket are inserted so that the socket is slidably connected to the tray. The slots may be located in the first tray portion.

In yet another aspect, the present invention relates to a device of the type described above in which a retaining element is provided which extends over an intermediate portion of the fiber alignment groove for securing the terminal end of the optical fiber in the fiber alignment groove. In still another aspect, the present invention relates to a device of the type described above in which a projection extending from within the tray is provided for automatically releasing the connector plug from the socket when the projection contacts a latch that is incorporated into the connector plug.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will best be understood by reference to the accompanying drawings, wherein:

FIG. 1 is a side view of a longitudinal section of one connector which may be cleaned using the present invention, the fiber optic connector including a plug and receptacle;

FIG. 2 is a perspective view of the plug and receptacle of FIG. 1, with a partial section revealing the bowed fibers in the plug interior;

FIG. 3 is a perspective view of one example of the plug used with the present connector, which plug is equipped with a sliding door;

FIG. 4 is a perspective view of one example of the receptacle used with the present connector, which receptacle provided with a hinged door having camming surfaces which cooperate with camming surfaces on the plug door;

FIG. 5 is a perspective view of one embodiment of a cleaning apparatus constructed in accordance with the present invention in which a connector plug has been inserted in preparation for cleaning;

FIG. 6 is a perspective view of the cleaning apparatus shown in FIG. 5 in which the upper and lower portions of the tray are separated so that a cleaning material can be inserted therebetween; FIG. 7 is a sectional view of the cleaning apparatus with the connector plug inserted therein;

FIG. 8 is a perspective view showing the interior of the socket seen in FIGS. 5-7;

FIG. 9 is another perspective view of the socket shown in FIG. 8 in which a door covers the socket opening; and FIG. 10 shows an alternative embodiment of the present invention.

DETAILED DESCRIPTION

The present invention is generally directed to cleaning the terminal end face of an optical fiber to be used in a connector or splice. However, these terms should not be construed in a limiting sense, since the present invention may be used in plug and receptacle designs which provide a permanent or temporary connection or termination.

With reference now to the figures, and in particular with reference to FIGS. 1 and 2, there is depicted an exemplary connector 10 having optical fibers whose plug ends may 0 be cleaned with the fiber optic cable cleaner of the present invention. Connector 10 generally comprises an elongate plug 12 and a socket or receptacle 14. FIG. 1 is a longitudinal section of the connector showing the plug fully inserted in the receptacle. The receptacle is mounted on a support surface or bulkhead 16. FIG. 2 is a perspective view with the bulkhead omitted, also with a partial longitudinal section to illustrate the 5 interior of the connector. The depicted connector provides for the interconnection of two pairs of fibers, but those skilled in the art will appreciate that the inventive concepts described herein extend to single pair interconnection as well as the interconnection of multiple pairs. Those skilled in the art will also appreciate that the connector can accommodate discrete optical fibers or multifiber ribbons, as well as both single mode and o multimode fibers, and that the cleaning device discussed below can be used with any such configurations.

The plug 12, shown also in FIG. 3, includes a fiber holder 18 which may be constructed of two clamping elements or blocks 20 and 22, and a plug body or shroud 24 which is attached to the fiber holder. The shroud may be removably attached to the fiber 5 holder by means of, e.g., latches 26 integrally molded onto the blocks, which engage cutouts 28 formed in the corresponding walls of the shroud. Fibers 30 and 32 which are to be interconnected or terminated pass through the fiber holder and into the hollow interior of the shroud. The terminal portions of the fibers are bare, that is, they are not affixed to any alignment member such as a ferrule. The shroud therefore serves not only to assist in o physically locating the plug in the receptacle, but also provides protection for the otherwise exposed terminal portions of the fibers. If required, the shroud can be made retractable to fully expose the fiber tips. The fiber holder has fiber-receiving grooves 34 formed in the adjacent surfaces of the blocks; these two components may be identical parts. The fiber holder may secure the fibers, for example, by a clamping action, through the use of adhesives, or through other suitable means. Alternative means may be used to secure the fibers to the fiber holder. Thus, for example, the fiber holder may have an extension 36 surrounding the fibers for additional strain relief and clamping. A boot 38 may be provided for further strain relief, to capture the strengthening members in the fiber cable (which may be, for example, aromatic polyamide fiber of the type sold by E. I. du Pont de Nemours & Co. under the brand name KEVLAR™), and to assist in handling the plug. The strengthening members need not be crimped but they may be adhered onto the holder. Strain relief of the strengthening members is attained by a force fit of straightwall section of the plug fiber holder within the boot. This is dependent upon the choice of materials used for the boot and the plug fiber holder, and yields a design that does not require a crimp ring and which assists in ease of manufacture and reduces the number of needed components. Alternatively, an extension may be formed on the holder with a

"torture" (irregular) path for clamping the strands and retaining the boot with an interference fit. "One-way" barbs on the surface of the plug fiber holder assist in the attachment of the boot to the plug fiber holder, which also assists in the attachment of the cable to the plug. In the embodiment of FIGS. 1 and 2, a latch 40 is integrally molded onto one side of the shroud to releasably secure the plug to the receptacle. The latch also imparts mechanical polarization to the plug, i.e., it can only be inserted into the receptacle in one orientation. The plug may be biased in the interconnected position, e.g., by a springboard (a flexible cantilever) formed inside the receptacle, to be pushed back against the latch to minimize the effect of manufacturing tolerances.

The fibers and extend generally straight within the shroud whenever the plug is not installed in the receptacle. The fibers are "generally" straight in that they extend without significant bowing, although there may be some minute flexing of the fibers as a result of gravity. Sufficient space is provided within the shroud, however, to allow the fibers to bow significantly, as seen in FIGS. 1 and 2, when the plug is fully inserted into the receptacle. The forward end 52 of the shroud has a pair of slots 54 and 56 formed therein which provide access to the terminal ends of the fibers located within the shroud. A hood or door 58 is slidably attached to forward end of the shroud, with two covers or bars 60, 62 which overlap slots 54 and 56, respectively, when the door is in the closed position of FIG. 3. When the door slides to the open position, the bars move to allow access to the fibers via slots 54 and 56, respectively, without the need for the fibers to extend outside of the shroud, although this would be acceptable in alternative designs. The door is slidably attached to the shroud with a snap fit resulting from two tongue-and-groove arrangements 64 and 66 (FIG. 1). In addition to preventing dust from entering through the slots, the door also prevents any light in the plug fibers from escaping and injuring a user's eyes

The receptacle 14, also shown in FIG. 4, includes a body or housing 70 and another fiber holder 72 (best seen in FIG. 2). The housing has an opening 74 whose size and shape generally corresponds to that of the forward end of the plug. The housing may also have appropriate features (such as latch arms 76) allowing it to be releasably mounted to the bulkhead which may be, for example, a patch panel or workstation outlet (wall box faceplate). The latch means may provide for mounting from the front of the panel, to allow all preparatory work to be done at the front side of the panel, or may provide for mounting from the rear of the panel, to allow all preparatory work to be done at the back side of the panel. The receptacle fibers (only one of which, 78, is visible in FIGS. 1 and 2) are secured to the receptacle fiber holder 72 by clamping as well, using a clamping plate 80 adapted to grip the fibers at a first end of the fiber holder. The terminal ends of the receptacle fibers extend into fiber-alignment grooves formed in projections or fingers 82 and 84 at a second end of the receptacle fiber holder. The grooves are preferably V- shaped, although they may be more rounded, i.e., U-shaped. An intermediate section 86 of the fiber-alignment grooves is curved so as to maintain the receptacle fibers in the grooves by the elastic urging of the slightly bowed fibers. The fibers do not extend to the very tips of the fingers 82 and 84 but rather terminate a sufficient distance from the tips to allow proper support of the plug fibers when the connector is in use. If the fiber-to-fiber contact occurs very near the tips of the V-grooves (or if the plug is inserted too far), the plug fiber can bend beyond the groove and lift away from the apex, breaking the connection. The receptacle may have as many of these fingers with fiber-alignment grooves as there are fibers in the plug. The fingers are shaped to project into slots 54 and 56, respectively, of the shroud when the plug is fully inserted into the receptacle. The fingers 82 and 84 enter the shroud at an oblique (nonzero) angle with respect the plug axis, i.e., the axis defined by either of the plug fibers 30 or 32 when they are extending straight within the shroud. This angle is preferably about 42°, which balances concerns regarding fiber end face contact pressure, fiber forces directed into the V-groove, the effects of friction, and the desired tolerance window (a larger angle increases tolerances). Since the receptacle fibers are not directed toward the opening 74, there is no danger of escaping light injuring a user's eyes. The receptacle fiber holder is pivotally attached to housing 70 by providing posts on the first end of the holder which snap into cutouts or hooks 88 formed at one end of the receptacle housing. The holder releasably locks into place using bumps or studs formed on the side of the holder, which engage holes 89 in the receptacle housing. An alternative design for the receptacle fiber holder may be used in which the holder is molded as a single piece with a breakaway top or cover plate that can snap onto its base, the base having the fiber-positioning grooves.

Fibers which are to be pre-terminated to either the plug or the receptacle should be stripped, cleaved and cleaned. If the fibers are in the form of a ribbon which is part of a bundled group of ribbons in a cable, then a portion of the cable jacket must first be cut back to reveal the ribbons. Most cables have several protective layers, and each of these layers must be removed to provide access to the fiber ribbons. Similar steps must be taken to remove the protective layers of a cable having a single discrete fiber. After the fibers have been removed from the protective cable jacket, they are stripped. The stripped fibers are then ready for cleaving, which may be accomplished using any one of several commercially available fiber cleavers, such as that shown in U.S. 5,024,363 (Suda et al.). The cleave length for attachment of the fibers to the plug is the distance from the fiber holder, which is about 23 mm. For attachment of fibers to the receptacle, the cleave length is the distance from the fiber holder 72 which is about 15 mm. Any debris should be cleaned off the fibers using a suitable cleaning solution such as alcohol. Prior to removing the fibers from the cleaver, the craftsperson may inspect the fibers to confirm that the end faces on all fibers are acceptable, i.e., that they are smooth cleaves with no spikes. The fiber viewer disclosed in U.S. 5,210,647 (Hartnagel et al.) may be used for this purpose. Once the craftsperson is satisfied that each of the fibers has an acceptable end face, the fibers may be removed from the cleaver. The fiber end faces are preferably flat with a chamfered or beveled periphery (or at least partially beveled) to obtain the advantages associated with such a fiber end profile, as discussed more thoroughly in U.S. patent application Ser. No. 08/122,755 (Carpenter). The fiber end faces may alternatively be radiused (generally spherical). The fibers may further optionally be provided with an asymmetric treatment, as may be attained by cleaving to impart an angled end face as 5 taught in U.S. Pat. No. 5,048,908 (Blonder et al.). If so, in order to minimize insertion losses and reflections, the fibers should be inserted in such a way that the orientation of the angled end faces of one set of fibers (i.e., those disposed within the plug) complements the orientation of the angled end faces of the other set of fibers (i.e., those disposed within the receptacle). For the plug fibers, fiber preparation may be done after the fiber cable has o been threaded through the boot.

Final assembly of the plug comprises the simple steps of clamping the fibers in the V-grooves of the fiber holder and snapping the shroud onto the holder. An assembly fixture may be used to guide the shroud onto the plug fiber holder so as to avoid damaging the fibers as they are inserted into the shroud. The ends of the plug fibers should terminate 5 about 0.5 mm from the end of the shroud. Completion of the receptacle is also simple.

The receptacle fibers are clamped onto the fiber holder 72 using clamping plate 80, with the ends of the receptacle fibers terminating in the fiber-alignment grooves about 15 mm from the tips of fingers 82 and 84. The receptacle fibers may be cleaved after securing them to the fiber holder. The fibers may be assembled into the holder using the V-groove 0 to actually pick up the fiber holder from the cleaver so as to avoid contamination of the fiber tips, if mating and guiding features are provided on one or both parts. A punch-down tool could also be used to simplify assembly. The fiber holder is attached to the housing 70, first by pushing the pivot posts into cutouts 88, and then snapping the studs into holes 89. Care should be taken during placement of the fibers in the V-grooves and attachment 5 of the holder to the receptacle to not contaminate the fiber tips.

Installation of the connector is equally straightforward. The receptacle is optionally mounted to any desired surface by convenient means, such as latching arms 76 (other constructions could be molded into housing 70 for custom mounting). Several receptacles could also be mounted in a single module, and they can be designed for front 0 or rear loading, or sliding from the side. After the receptacle is mounted, the connection is completed by simply inserting the plug into opening 74. The plug is released from the receptacle by a latch 40. FIGS. 1 and 2 depict full insertion of the plug. As the plug is inserted, the plate 90 opens and cams door 58 open as described above, allowing fingers 82 and 84 to enter slots 54 and 56, respectively. Plug fibers 30 and 32 contact the fiber-alignment grooves in the fiber holder and slide until their end faces abut the respective end faces of the receptacle fibers. The fibers then become bowed when the plug is fully inserted. The plug fibers may undergo an S-shaped bend. All force at the fiber-to-fiber interface comes from the resilience (elastic deformation) of the bowed fibers which maintains a continuous compressive load between the ends. The connector is preferably designed to maintain a minimum bend radius of 0.3" on the fibers. The dimensions of the various components of the connector may vary considerably depending upon the desired application. The following approximate dimensions are considered exemplary. The plug 12 has an overall length of 57 mm, a width of 12 mm, and a thickness of 8 mm, and the plug fiber holder 18 provides clamping grooves that are 13 mm long. The plug shroud 24 extends 25 mm beyond the fiber holder, providing an interior space which is 24 mm long, 10 mm wide and 6 mm high. The opening 74 of the receptacle 14 is 12 mm x 10 mm. Its overall height and depth are 38 mm and 36 mm, respectively. Receptacle fiber holder 72 is 20 mm long (from the end where the fibers are clamped to the tips of fingers 82 and 84), 12 mm wide and 1.5 mm thick. The fiber- alignment grooves in the fingers are 11.5 mm long and have a maximum depth of 2 mm which suitably accommodates most conventional optical fibers. The interior angle of the

V-grooves should not be too narrow since this might result in excess friction with the fibers, but it also should not be too wide since this would not keep the fibers guided properly. A 90° interior angle is believed to be a good compromise.

FIGS. 5-7 show a cleaning apparatus in accordance with the present invention. The apparatus includes an upper tray portion 202, a lower tray portion 204, and a socket

206 for receiving a plug 212 during the cleaning process. The plug is of the type depicted in FIGS. 1-3 as plug 12. The upper tray portion has laterally extending slots 208 along its sidewalls in which projections 216 of the socket 206 (best seen in FIG. 8) are inserted so that the socket is retained in the upper tray portion while being slidable therein between the front and back ends 232 and 230. The upper tray portion also includes an orifice 210 at its front end through which liquid solvent can be inserted. In one embodiment of the invention, the orifice has a size and shape that conforms to a spray head of a spray bottle in which the liquid solvent resides. For example, the orifice may conform to the spray head that is supplied with the VF-45 cleaning kit, which is available from the Minnesota Mining & Manufacturing Co. (3M).

The lower tray portion is pivotably connected to upper tray portion at the back end. As seen in FIG. 6, the lower and upper tray portions rotate to contact one another to form a tray. The lower tray portion defines the bottom of the tray and the upper tray portion defines the sidewalls of the tray. The bottom of lower tray portion has a laterally extending raised surface 222 that serves as the surface against which the fiber end faces are to be cleaned. 0 The socket 206, shown in FIG. 8, is similar in design to the receptacle 14 of the connector 10. The socket includes a housing 224 that has an opening whose size and shape generally corresponds to that of the front end of the plug. The latch 240 on the plug ensures that plug is releasably securable in the socket in a manner similar to the arrangement employed in connection with receptacle 14. When the socket is properly 5 positioned in the upper tray portion (i.e., when the projections are inserted in the slots

208), it is oriented so that its opening 234 is angled as shown in FIG. 7 so that when the plug 212 is inserted, the plug extends outwardly therefrom at an angle of about 40°. The interior of the socket includes a ridge 228 in which fiber alignment grooves 218 are formed. The grooves are preferably V-shaped, although they may be more rounded, i.e., o U-shaped. When the plug is initially placed at the opening of the socket prior to its complete insertion, the terminal ends of the plug fibers extend into the upper portion of the fiber alignment grooves. Retainers 220 are provided over the fiber alignment grooves to ensure that the fibers remain in the grooves as the plug is fully inserted into the socket. That is, the retainers serve as fulcrums against which the fibers elastically bend so that 5 they are urged along the grooves. The retainers should be located at a position along the grooves such that when the fibers are inserted into the grooves, they initially come into contact with the grooves at a position above the retainers. The fibers subsequently slide down the grooves so that they pass through the opening defined by the retainers and the grooves. In one particular embodiment of the invention designed for cleaning fibers in the o exemplary plug having the previously noted dimensions, the retainers are located at least

1.7 mm from the top of the fiber alignment grooves. As shown in FIG. 9, the socket 206 may have a flap or socket door 90 to minimize entry of contaminants through the opening 234. The disclosed embodiment uses a socket door which cooperates with the plug door 58 (see FIG. 3) to actuate the plug door between closed and open states as the plug 212 is inserted into the socket 206. Specifically, the socket door has two camming surfaces 92 and 94 which interact with camming surfaces 96 and 98, respectively, on the plug door 58. The socket door is hinged along one edge by providing posts 100 that snap into cutouts 102 in the socket housing 224. Means (not shown), such as a spring or camming linkages molded into the part, may be used to bias the door in the closed position. When the plug is inserted into the socket, the forward end 0 52 of the plug and the plug door push against the socket door, raising and opening it. The ramped camming surface 94 then begins to forcibly abut the camming surface 98 on the plug door 58, pushing the door to the side to reveal slots 54 and 56. If the plug is thereafter removed from the socket, then the ramped camming surface 92 similarly pushes against the camming surface 96 as the plug is removed, sliding the plug door 58 back into 5 its closed position. The grooves or indentations 104 and 106 in the plug shroud accommodate the camming surfaces 92 and 94 when the plug is in the socket, which also serve to further stabilize the connection. Other door designs may be implemented with the socket 206, such as a door which manually opens outward and snaps shut.

When the plug is fully inserted into the socket, the terminal ends of the fibers o project beyond the lower end of the grooves 218 and into the tray so that they are situated over the raised surface 222 of the lower tray portion 204. However, the fibers do not extend so far along the grooves that their end faces contact the raised surface. Rather, a gap remains between the fiber end faces and the raised surface which is sufficiently wide to allow a cleaning medium such as a cloth to be inserted therebetween. 5 The cleaning apparatus 200 is used in the following manner. The upper and lower tray portions 202 and 204 are pivoted away from one another and a sheet of lint-free cloth such as a 100% hydro-entangled polyester wiper or other cleaning medium is placed over the bottom of the lower tray portion. The sheet preferably covers substantially the entire bottom of the lower tray portion, including the raised surface 222, and extends beyond its o edges so that when the upper tray portion is closed the sheet is held in place between the upper and lower tray portions. Prior to insertion of the plug, the socket is located at the back end 230 of the tray. The plug 212 is then inserted into the socket as shown in FIG. 7 so that the terminal ends of the fibers extend through the grooves 218 and contact the cleaning medium. Liquid solvent is then applied to the cleaning medium through orifice 210. Alternatively, of course, the liquid solvent may be applied directly to the cleaning medium through the opening in the top of the tray or may even be applied prior to inserting the cleaning medium in the tray. The plug and socket unit is then slid forward so that it advances toward the front end 232 of the tray. The user will typically perform this step by grasping the plug and pulling it toward the front end of the tray. Since the fiber end faces are in contact with the now solvent-saturated cleaning medium, the fiber end faces are cleaned while the socket 206 is slid forward in the tray. In a preferred embodiment of the invention the plug is automatically released from the socket once the socket contacts the front end 232 of the tray. For this purpose, an inclined surface 214 projects inwardly from the front end of the tray. As best seen in FIG. 6, the inclined surface is oriented so that it serves as a release mechanism by pressing on the latch 240 as the plug and socket are advanced toward the front end of the tray. Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modifications of the disclosed embodiment, as well as alternative embodiments of the invention, will become apparent to persons skilled in the art upon reference to the description of the invention. For example, as shown in FIG. 10, the upper and lower tray portions may have a variety of different configurations. The tray shown in FIG. 10 is easier to use because it provides a releasable latch 240 at the front end 232 of the tray that locks the upper tray portion to the lower tray portion. In addition, the tray shown in FIG. 10 is easier to manufacture than the previously shown tray. It is therefore contemplated that such modifications can be made without departing from the spirit or scope of the present invention as defined in the appended claims.

Claims

WHAT IS CLAIMED IS:

1. A device for cleaning the end face of a bare optical fiber retained within a connector plug, comprising: a tray having a cleaning surface; and a socket slidably connected to the tray, said socket having an opening sized to receive the connector plug, said socket further having a projection equipped with at least one fiber alignment groove adapted to receive a terminal portion of the optical fiber located in the connector plug when the plug is inserted in said socket; wherein said groove is positioned with respect to said tray such that the end face of the optical fiber located in the connector plug extends beyond the groove and remains substantially uniformly spaced from, and exposed to, the cleaning surface of the tray when the socket slides in the tray.

2. The device of claim 1 , wherein the position of the groove with respect to the tray is such that there exists a space between an end of the groove and the cleaning surface, said space being sufficient to position a cleaning medium therein that contacts both the cleaning surface of the tray and the fiber end face that extends beyond the end of the groove.

3. The device of claim 1 , wherein the tray comprises first and second tray portions pivotably connected to one another, said second tray portion defining a bottom of the tray on which said cleaning surface resides.

4. The device of claim 4, wherein said tray includes sidewalls having slots in which projections of the socket are inserted so that the socket is slidably connected to the tray.

5. The device of claim 4, wherein said slots are located in the first tray portion.

6. The device of claim 3, wherein said first tray portion is equipped with an orifice through which a liquid solvent is insertable.

7. The device of claim 3, wherein a direction normal to said socket opening forms an angle of about 40° with respect to said bottom of the tray when first and second tray portions are in a closed position.

8. The device of claim 1 , further comprising a retaining element extending over an intermediate portion of said fiber alignment groove for securing the terminal end of the o optical fiber in the fiber alignment groove.

9. The device of claim 1, further comprising a door member attached to the socket, said door member being movable between a closed position wherein said door member covers said opening and an open position wherein said opening is unobstructed by said 5 door member.

10. The device of claim 1 , wherein the connector plug includes a latch for releasably securing the plug in the socket and further comprising a projection extending from within the tray for automatically releasing the connector plug from the socket when the projection o contacts the latch.

11. The device of claim 2, wherein the socket is slidable over a prescribed length of the tray and wherein said cleaning surface extends approximately over said prescribed length. 5

12. The device of claim 3, further comprising a releasable latch connecting said upper tray portion to said lower tray portion at an end of the tray remote from the pivotable connection.

13. In combination with a connector plug having the end face of a bare optical fiber disposed therein, a device for cleaning the end face of the optical fiber, said device comprising: a first element having a cleaning member disposed thereon; and a second element, pivotally connected to said first element, said second element having a socket disposed therein which is adapted to receive the connector plug, said socket further having a projection equipped with at least one fiber alignment groove adapted to receive a terminal portion of the optical fiber disposed in the connector plug 0 when said plug is inserted in said socket; wherein said groove is positioned with respect to said first element such that the end face of the optical fiber disposed in the connector plug extends beyond the groove and remains substantially uniformly spaced from, and exposed to, the cleaning surface of the first element. 5

14. The combination of claim 13, wherein said socket is slidably disposed within said second element.

15. In combination with a connector plug having a first housing with the end face of a o bare optical fiber disposed therein, said first housing being movable from a first position in which the end face is concealed inside the first housing to a second position in which the end face is exposed, a cleaning device for cleaning the end face, said cleaning device comprising: a cleaning element disposed within a second housing; and 5 a receptacle disposed on the surface of said second housing, said receptacle being adapted to receive the connector plug and to maintain the first housing in the second position when the connector plug is inserted into the receptacle, thereby exposing the end face of the optical fiber to the cleaning element.

16. The combination of claim 15, further comprising: a passageway disposed within said second housing, said passageway being adapted to receive the terminal portion of the optical fiber and being further adapted to maintain the terminal portion of the optical fiber in a fixed position with respect to the cleaning element.

17. The combination of claim 15, wherein said cleaning device comprises a first element comprising said receptacle and a second element comprising said cleaning element, and wherein said first element is movable with respect to said second element.