WO2001027674A2

WO2001027674A2 - Optical monitoring device

Info

Publication number: WO2001027674A2
Application number: PCT/DE2000/003619
Authority: WO
Inventors: Bernhard Deutsch
Original assignee: Scc Special Communication Cables Gmbh & Co. Kg
Priority date: 1999-10-15
Filing date: 2000-10-13
Publication date: 2001-04-19
Also published as: WO2001027674A3; DE19949845A1

Abstract

The monitoring device comprises a demultiplexer (DM), which has in particular, N-outputs (Al-An), a splitter (S1-Sn) being allocated to each of said outputs (Al-An) which define a transmission channel. The signal which has been transmitted via the corresponding channel is present at the respective output (SA1-SAn) of each splitter (S1-Sn) and the monitor signal which has been assigned to the channel signal and which is fed to a detector is present at the second output (MA1-MAn) of the splitter (S1-Sn). The demultiplexer (DM) and the splitters (S1-Sn) which are connected to the demultiplexer outputs (Al-An) using splicers, are placed in a housing equipped with standardised light wave cable connectors.

Description

description

Optical monitoring device

The invention relates to an optical monitoring device with an optical multiplexer / demultiplexer and at least one optical splitter (splitter, divider) for checking an input or output signal of the multiplexer / demultiplexer.

In optical wavelength division multiplexers or wavelength demultiplexers (WDM = Wavelength Division Multiplexing = Wavelength Division Multiplexing) the different wavelengths of optical transmission channels are summarized or divided (see for example LASER FOCUS WORLD, June 1998; pp. 83-88). This means that several channels can be transmitted simultaneously via a single optical fiber. To monitor the function of the multiplexers / demultiplexers in a network, the channels must be tapped optically by means of a splitter / splitter and fed to a detector via a monitor output. At the current state of the art, both the multiplexer / demultiplexer and the splitter are discrete components that have to be individually installed and connected one after the other. Therefore, several housings are necessary, which have to be tested and qualified individually and then together. In addition, the components must be individually integrated in plug-in modules. If the number of channels is higher, for example 16 or 32 channels, the assembly becomes complex for the user and therefore prone to errors.

In contrast, the object of the invention is to provide a monitoring device with which the channels defined by an optical multiplexer / demultiplexer can be checked in a simple manner. To achieve this object, a device of the type mentioned at the outset is characterized in that the multiplexer / demultiplexer and the splitter are integrated in one module. Since the module is in a prefabricated form, the assembly time on the part of the user is reduced and the susceptibility to errors of the module is reduced. The fulfillment of the relevant requirements, for example the Bellcore GR-1221-CORE, can already be fulfilled and guaranteed by the manufacturer.

An advantageous embodiment of the invention is characterized in that the connections between the multiplexer / demultiplexer and the splitters are thermal splices, as a result of which permanent connections which are satisfactory in their transfer function are established between the multiplexer / demultiplexer and the splitters.

A further advantageous embodiment of the invention is characterized in that the multiplexer / demultiplexer and the splitter are integrated on a chip of a planar optical fiber component (LWL = optical waveguide), additional connections between the multiplexer / demultiplexer and the splitters being avoided overall, so that the reliability of the module is further improved.

A further advantageous embodiment of the invention is characterized in that the multiplexers / demultiplexers and the splitters are integrated in one housing. It is therefore possible without further ado to accommodate the module or the housing in a slot in a control cabinet of the transmission system, which further reduces the module's susceptibility to errors.

A further advantageous embodiment of the invention is characterized in that for each channel of the multiple xers / De ultiplexers a splitter is provided so that a separate monitoring option can be provided separately for each channel.

A further advantageous embodiment of the invention is characterized in that a splitter is provided in the incoming or outgoing transmission link for monitoring the overall function, so that the overall function of the multiplexer / demultiplexer and the transmission link can advantageously be continuously monitored.

A further advantageous embodiment of the invention is characterized in that an unused optical gate of a splitter is optically terminated with a return loss of greater than 30 dB, which ensures that the part of the signal transmitted on the splitter is fully used as a monitor signal is available.

Another advantageous embodiment of the invention is characterized in that the optical channel output lines are fiber optic pigtails, for which a number of processing methods known per se can be used for connecting or assembling this output line.

A further advantageous embodiment of the invention is characterized in that the input / output lines of the module or the fiber optic pigtails have standard interfaces in the form of fiber optic connectors with standard plug faces, for example SC, E 2000 and the like, wherein the outputs of the module are contacted in an advantageous manner by standard connectors and can thus be easily and securely integrated into the network of the transmission system. A further advantageous embodiment of the invention is characterized in that the division ratio of the splitters is between 1 to 99 and 10 to 90, the energy transmitted in the relevant channels or the corresponding signals being reduced only insignificantly by branching off monitor or monitoring signals ,

A further advantageous embodiment of the invention is characterized in that the wavelength range of the splitters is broadband in the range from 1530 to 1565 nm (C-band) or in the range from 1565 to 1625 nm (L-band), so that the operating wavelength range of the multiplexers / Demultiplexers can advantageously be covered by the splitters without impairment.

A further advantageous embodiment of the invention is characterized in that the housing for the module has on one side signal outputs in the case of a de ultiplexer, signal inputs in the case of a multiplexer and a signal input in the case of a demultiplexer or a signal output in the case of a multiplexer, and that monitor outputs are arranged on the other side of the housing, although the monitor outputs and the signal inputs and

Signal outputs can be arranged on the same side of the housing, it is advantageous to arrange the monitor outputs on one side and the signal inputs or signal outputs on the other side of the housing, because this enables the functions of the outputs when integrating the module into transmission systems can differentiate better.

Embodiments of the invention will now be described with reference to the accompanying drawings. Show it: Figure 1 is a schematic representation of a module with a demultiplexer and splitters;

Figure 2 is a schematic representation of a module with splitters and a multiplexer; FIG. 3 shows a schematic representation of a module with a demultiplexer, a splitter in the incoming transmission link and individual splitters in the outgoing transmission links;

Figure 4 shows a housing in which the multiplexer / demultiplexer and the splitter are housed.

FIG. 1 shows a schematic representation of a module with an optical demultiplexer DM and optical splitters Si to S _n in the respective output lines Aj to A _{n of} the de-diplexer DM. An input signal arriving at an input line E with the wavelengths λl, 2,. .., n is split in the demultiplexer DM into n output signals SAi to SA _n with the wavelengths λl to λn. The output signal with the wavelength λl on the output line i is split in the splitter Si into a signal output SA _α and a monitor output MAx. The division ratio is 10 to 90, i.e. the percentage of the power at the monitor output MA _α is 10% of the output power at the signal output SAi. The unused optical gate Ti of the splitter Si is closed with a return loss of greater than 30 dB. The same applies to the splitters S ₂ to S _n , as shown in Figure 1.

FIG. 2 schematically shows a module with a multiplexer M and splitters S ₁ to S _n in the input lines El to En of the multiplexer M. The splitters Si to S _n thus monitor the signals that arrive on the input lines Ei to E _{n of} the multiplexer M. , and the monitor signals are present at the monitor outputs MA _X to MA _n . The signal output SA is present at the output A of the multiplexer M. The ballast and The function of the splitter in this example is analogous to the example in FIG. 1.

FIG. 3 shows the schematic representation of a module as shown in FIG. 1, a further splitter S _{M being} provided in the input line E, which monitors the overall function of the module. By comparing the monitor output MA of the splitter S _M with the monitor outputs MAi to MA _{n of} the splitters Si to S _n , knowledge about the function of the demultiplexer DM can be obtained. An analogous arrangement is of course also possible in the embodiment of FIG. 2.

FIG. 4 shows a housing B in which a module of the type shown in FIGS. 1 to 3 is arranged. The signal outputs Ai to A ₄ if the housing B contains a demultiplexer, or the signal inputs Ei to E if the housing B contains a multiplexer, and a signal input E if the housing contains a demultiplexer, or a signal output A if the housing contains a multiplexer are shown on the right side of the housing B. The monitor outputs MAi to MA ₄ are arranged on the left side of the housing B. This applies to the case of four channels. Instead of the pigtails shown, connectors can also be provided for the pigtails or on the housing B.

Claims

claims

1. A device with an optical multiplexer / demultiplexer and at least one optical splitter for monitoring the function of the multiplexer / demultiplexer, since the multiplexer / demultiplexer and the splitter are integrated in one module.

2. Device according to claim 1, d a d u r c h g ek e n n z e i c h n e t that the connections between the multiplexer / demultiplexer and the splitters are thermal splices.

3. Device according to claim 1, d a d u r c h g ek e n n z e i c h n e t that the multiplexer / demultiplexer and the splitter are integrated on a chip of a planar optical fiber component.

4. Device according to claim 1 or 3, d a d u r c h g e k e n n z e i c h n e t, that the multiplexer / demultiplexer and the splitter are integrated in one housing.

5. The device according to claim 1, which also includes a splitter for each channel of the multiplexer / demultiplexer.

6. Device according to one of the preceding claims, characterized in that a splitter is provided in the incoming or outgoing transmission link for monitoring the overall function of the module.

7. Device according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t, that an unused optical gate of a splitter with a return loss of greater than 30 dB is optically terminated.

8. Device according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t, that the optical channel output lines are fiber optic pigtails.

9. Device according to claim 8, d a d u r c h g ek e n n z e i c h n e t, d a s s have the input / output lines of the module or the fiber optic pigtails standard interfaces in the form of fiber optic connectors with standard mating faces, for example SC, E 2000 and the like.

10. Device according to one of the preceding claims, that a d u r c h g e k e n n e e i c h n e t that the splitting ratio of the splinters is between 1 to 99 and 10 to 90.

11. Device according to one of the preceding claims, d a d u r c h g e k e n n z e i c h n e t that the wavelength range of the splitter is broadband in the range from 1530 to 1565 nm or in the range from 1565 to 1625 n.

12. Device according to one of the preceding claims, characterized in that the housing for the module on one side has signal outputs in the case of a demultiplexer, signal inputs in the case of a multiplexer and a signal input in the case of a demultiplexer or a signal output in the case of a multiplexer and in that Monitor outputs are arranged on the other side of the housing.