JP2012034102A - Wavelength multiplex signal light receiving apparatus and light wavelength multiplex transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wavelength multiplex signal light receiving apparatus and light wavelength multiplex transmission system, capable of preventing the erroneous detection of reflected light in the output terminal of an optical amplifying unit.SOLUTION: A wavelength multiplex signal light receiving apparatus includes: an optical amplifying unit that receives multiplex signal light obtained by multiplexing a plurality of signal lights each having a different wavelength and amplifies the multiplex signal light; a light wavelength separation unit that separates the signal light from the multiplex signal light amplified by the optical amplifying unit; and a plurality of signal light receiving units that receive the signal light separated by the light wavelength separation unit and outputs it to a required client device. The wavelength multiplex signal light receiving apparatus further includes an optical isolator that allows the multiplex signal light output from the optical amplifying unit to the light wavelength separation unit to pass through the optical isolator and blocks the light output from an input terminal of the light wavelength separation unit to an output terminal of the optical amplifying unit .

Description

  The present invention relates to a wavelength multiplexed signal light receiving apparatus that receives multiplexed signal light in which a plurality of signal lights having different wavelengths are multiplexed, and an optical wavelength division multiplexing transmission system including the wavelength multiplexed signal light receiving apparatus.

  As a technique for coping with the increase in network traffic accompanying the spread of the Internet, particularly broadband, there is an optical wavelength multiplexing transmission system that multiplexes a plurality of signal lights having different wavelengths and transmits / receives them through one transmission line such as an optical fiber.

  FIG. 3 shows a configuration example of a background art of a wavelength multiplexed signal light receiving apparatus that receives multiplexed signal light obtained by multiplexing a plurality of signal lights, which is used in an optical wavelength multiplexing transmission system.

  As shown in FIG. 3, the wavelength multiplexed signal light receiving apparatus 1 includes an optical amplifying unit 11 that amplifies received multiplexed signal light, and light that separates each signal light from the multiplexed signal light amplified by the optical amplifying unit 11. The wavelength separation unit 12 includes a plurality of signal light reception units 13 that receive the signal light separated by the optical wavelength separation unit 12 and output the signal light to a required client device such as an optical switch or a router.

  In an optical communication system, signal light (multiplexed signal light) that is propagating in a transmission path composed of an optical fiber is attenuated, and is weak light that is close to the sensitivity limit of the photodetector at the receiving end of the wavelength multiplexed signal light receiving apparatus 1. May be. The optical amplifying unit 11 shown in FIG. 3 is provided to amplify such weak light.

  FIG. 4 is a block diagram illustrating a general configuration example of the optical amplification unit illustrated in FIG. 3. FIG. 4 shows an example of a bidirectional pumping type optical amplifying unit using an erbium-doped optical fiber (EDF: Erbium Doped Fiber).

  As shown in FIG. 4, the optical amplifying unit 11 includes the EDF 101, the first excitation light source 102 and the second excitation light source 103 that generate the excitation light input to the EDF 101, reflected light to the output end of the EDF 102, and the like. An optical isolator 104 for preventing input, a reflected light detection unit 105 for measuring the level of reflected light from the output end of the optical amplification unit 11, and the first excitation light source 102 for the input light to the optical amplification unit 11 A first optical multiplexing / demultiplexing unit 106 for multiplexing the generated pumping light, a second optical multiplexing / demultiplexing unit 107 for multiplexing the pumping light generated by the second pumping light source 103 to the output light of the EDF 101, A third optical multiplexing / demultiplexing unit 108 for demultiplexing the reflected light from the output end of the optical amplification unit 11 and sending it to the reflected light detection unit 105 is provided.

  In the optical amplifying unit 11, if the subsequent optical element is not normally connected to the output end, high output light may be emitted from the output end, so stop the optical output in consideration of safety. Is desirable. The reflected light detection unit 105 shown in FIG. 4 is provided to detect reflected (Fresnel reflection) light from the output end that occurs when the optical element at the subsequent stage is not connected. The reflected light detection by the reflected light detection unit 105 is also used for monitoring the quality of a transmission line composed of the optical fiber when, for example, an optical fiber is connected to the output end of the optical amplification unit 11.

  The wavelength multiplexed signal light receiving apparatus 1 has a detailed configuration described in Patent Document 1 and the like. Further, the detailed configuration of the optical amplifying unit 11 is also described in Patent Document 2 and the like.

JP 2003-198478 A Japanese Patent Laid-Open No. 11-261495

  In the wavelength-multiplexed signal light receiving apparatus 1 described above, for example, when the signal light receiving unit 13 is not normally connected to the optical wavelength separating unit 12, the signal light is reflected at the output end of the optical wavelength separating unit 12. When the wavelength multiplexed signal light receiver 1 and the wavelength multiplexed signal light transmitter for transmitting multiplexed signal light are accommodated in the same casing, the wavelength multiplexed signal receiver 1 and the wavelength multiplexed signal light transmitter Since the configuration is similar, at the time of manufacturing or maintenance, the optical wavelength demultiplexing unit 12 is mistaken for an optical wavelength multiplexing unit that multiplexes a plurality of signal lights, and the signal light is transmitted to the output end of the optical wavelength demultiplexing unit 12 There is also a possibility that an optical element for inputting is erroneously connected.

  In general, the optical wavelength demultiplexing unit 12 and the optical wavelength multiplexing unit have a structure in which light can be input from both the input end and the output end, and reflected light from the output end of the optical wavelength demultiplexing unit 12 or the output end. The light input in the opposite direction passes through the optical wavelength separation unit 12 and reaches the output end of the preceding optical amplification unit 11, and is reflected by the reflected light detection unit 105 as reflected light at the output end of the optical amplification unit 11. Misdetected.

  Here, when the reflected light detection unit 105 erroneously detects that the reflected light is above a predetermined level, a communication system including a plurality of wavelength-multiplexed signal light receiving apparatuses 1 and multiplexed signal light transmitting apparatuses, for example, When a sequence that stops not only the detected optical output of the optical amplifying unit 11 but also the operation of the entire communication system is adopted, another wavelength multiplexed signal light receiving device that does not include the erroneously detected optical amplifying unit 11 1 also stops operation.

  An erroneous connection to the optical wavelength demultiplexing unit 12 can be detected, for example, by monitoring a transmission / reception signal by a client device or a device connected to a subsequent stage of the client device. , Which may be a greater problem for the communication system. Therefore, it is important to prevent erroneous detection of reflected light at the output end of the optical amplifying unit 11 in the wavelength multiplexed signal light receiving apparatus 1 and the optical wavelength multiplexing transmission system including the wavelength multiplexed signal light receiving apparatus.

  The present invention has been made in order to solve the problems of the background art as described above, and a wavelength-multiplexed signal optical receiver capable of preventing erroneous detection of reflected light at the output end of an optical amplifier, and the wavelength-multiplexed signal An object of the present invention is to provide an optical wavelength division multiplexing transmission system including an optical receiver.

In order to achieve the above object, a wavelength multiplexed signal light receiving apparatus of the present invention is a wavelength multiplexed signal light receiving apparatus that receives multiplexed signal light obtained by multiplexing a plurality of signal lights having different wavelengths,
An optical amplifier for amplifying the multiplexed signal light;
An optical wavelength separation unit for separating the signal light from the multiplexed signal light amplified by the optical amplification unit;
A plurality of signal light receiving units that receive the signal light separated by the optical wavelength separation unit and output the signal light to a required client device;
An optical isolator that passes multiplexed signal light output from the optical amplification unit to the optical wavelength separation unit and blocks light output from the input end of the optical wavelength separation unit to the output end of the optical amplification unit;
Have

On the other hand, the optical wavelength division multiplexing transmission system of the present invention, the wavelength division multiplexing signal light receiving device,
A plurality of signal light transmitters that receive signals transmitted from required client devices and output signal lights having different wavelengths, an optical wavelength multiplexer that multiplexes the plurality of signal lights output from the signal light transmitters, and A wavelength-multiplexed signal light transmission device including an optical amplification unit that amplifies the multiplexed signal light output from the optical wavelength multiplexing unit and transmits the amplified signal light to the wavelength-multiplexed signal light receiving device via a transmission path;
Have

  According to the present invention, it is possible to obtain a wavelength-multiplexed signal light receiving apparatus that can prevent erroneous detection of reflected light at the output end of the optical amplifier.

It is a block diagram which shows one structural example of the wavelength division multiplexing optical signal receiver of this invention. It is a block diagram which shows the example of 1 structure of the optical wavelength division multiplex transmission system of this invention. It is a block diagram which shows the structural example of the wavelength multiplexing signal optical receiver of background art. FIG. 4 is a block diagram illustrating a general configuration example of an optical amplification unit illustrated in FIG. 3.

  Next, the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an example of the configuration of a wavelength multiplexed signal light receiving apparatus according to the present invention. In FIG. 1, the same reference numerals are assigned to the same optical elements as the optical elements included in the wavelength multiplexed signal light receiving apparatus of the background art shown in FIG. 3. Further, the optical amplifying unit 11 shown in FIG. 1 has the same configuration as the optical amplifying unit 11 shown in FIG.

  As shown in FIG. 1, a wavelength multiplexed signal light receiver 1 according to the present invention amplifies received multiplexed signal light, and each signal light from the multiplexed signal light amplified by the optical amplifier 11. An optical wavelength separation unit 12 that separates the optical signal, and a plurality of signal light reception units 13 that receive the signal light separated by the optical wavelength separation unit 12 and output the signal light to a required client device such as an optical switch or a router. In this configuration, the wavelength separation unit 12 includes an optical isolator 14 that blocks light output to the optical amplification unit 11.

  The optical amplifying unit 11 amplifies the multiplexed signal light input to the wavelength multiplexed signal light receiving apparatus 1 to a predetermined level. The optical wavelength separation unit 12 separates the multiplexed signal light output from the optical amplification unit 11 into a plurality of signal lights having different wavelengths. The signal light receiving unit 13 receives the signal light separated by the optical wavelength separation unit 12 and transmits the signal light to a required client device such as an optical switch or a router.

  The optical isolator 14 is an optical element that allows signal light to pass only in one direction, allows the multiplexed signal light output from the optical amplification unit 11 to the optical wavelength separation unit 12 to pass, and transmits light from the input end of the optical wavelength separation unit 12. The light output to the output terminal of the amplifying unit 11 is blocked. The optical isolator 14 does not have to be disposed in the optical wavelength separation unit 12 and may be connected as an independent optical element between the optical amplification unit 11 and the optical wavelength separation unit 12. However, the incorporation of the optical isolator 14 in the optical wavelength separation unit 12 reduces the number of contacts due to the connection connector and the like, and improves the reliability of the wavelength multiplexed signal light receiving apparatus.

  In the wavelength multiplexed signal light receiving apparatus 1 as shown in FIG. 1, the reflected light from the output end of the optical wavelength separation unit 12 or the light erroneously input from the output end of the optical wavelength separation unit 12 Even if the light passes through 12 and travels in the direction of the input end, it will not be blocked by the optical isolator 14 and output from the input end of the optical wavelength demultiplexing unit 12 to the output end of the optical amplification unit 11.

  Therefore, erroneous detection of reflected light by the reflected light detection unit 105 at the output end of the optical amplification unit 11 is prevented. In addition, since the reflected light from the output end of the optical wavelength separation unit 12 is not input to the reflected light detection unit 105 provided in the optical amplification unit 11, a decrease in the level measurement accuracy of the reflected light in the optical amplification unit 11 is suppressed. .

  FIG. 2 is a block diagram showing a configuration example of the optical wavelength division multiplexing transmission system of the present invention.

  As shown in FIG. 2, the optical wavelength division multiplexing transmission system of the present invention includes the wavelength division multiplexed signal light receiving apparatus 1 shown in FIG. 1 and a transmission line 3 such as an optical fiber connected to the wavelength multiplexed signal optical receiving apparatus 1. And a wavelength-multiplexed signal light transmitter 2 that transmits multiplexed signal light.

  The wavelength multiplexing signal light transmission device 2 receives a signal transmitted from the client device, and outputs a plurality of signal light transmission units 23 that output signal lights having different wavelengths, and a plurality of signal light transmission units 23 that output the signal light transmission units 23. An optical wavelength multiplexing unit 22 that multiplexes the signal light, and an optical amplifier that amplifies the multiplexed signal light output from the optical wavelength multiplexing unit 22 and transmits the amplified signal light to the wavelength multiplexed signal optical receiver 1 via the transmission path 3 such as an optical fiber. Part 21.

  According to the optical wavelength division multiplexing transmission system shown in FIG. 2, erroneous detection of reflected light by the reflected light detection unit 105 provided in the optical amplification unit 11 of the wavelength multiplexed signal light receiving apparatus 1 is prevented. In addition, a decrease in the level measurement accuracy of the reflected light by the reflected light detection unit 105 is suppressed. Therefore, a more reliable optical wavelength division multiplexing transmission system can be obtained.

DESCRIPTION OF SYMBOLS 1 Wavelength multiplexed signal light receiver 2 Wavelength multiplexed signal light transmitter 3 Transmission path 11, 21 Optical amplifier 12 Optical wavelength separator 13 Signal light receiver 14, 104 Optical isolator 22 Optical wavelength multiplexer 13 Signal light transmitter 101 EDF
102 1st excitation light source 103 2nd excitation light source 105 Reflected light detection part 106 1st optical multiplexing / demultiplexing part 107 2nd optical multiplexing / demultiplexing part 108 3rd optical multiplexing / demultiplexing part

Claims (3)

A wavelength-multiplexed signal light receiving apparatus that receives multiplexed signal light obtained by multiplexing a plurality of signal lights having different wavelengths,
An optical amplifier for amplifying the multiplexed signal light;
An optical wavelength separation unit for separating the signal light from the multiplexed signal light amplified by the optical amplification unit;
A plurality of signal light receiving units that receive the signal light separated by the optical wavelength separation unit and output the signal light to a required client device;
An optical isolator that passes multiplexed signal light output from the optical amplification unit to the optical wavelength separation unit and blocks light output from the input end of the optical wavelength separation unit to the output end of the optical amplification unit;
A wavelength-multiplexed signal light receiving apparatus.   The wavelength-multiplexed signal light receiving apparatus according to claim 1, wherein the optical isolator is incorporated in the optical wavelength separator. The wavelength division multiplexing optical receiver according to claim 1 or 2,
A plurality of signal light transmitters that receive signals transmitted from required client devices and output signal lights having different wavelengths, an optical wavelength multiplexer that multiplexes the plurality of signal lights output from the signal light transmitters, and A wavelength-multiplexed signal light transmission device including an optical amplification unit that amplifies the multiplexed signal light output from the optical wavelength multiplexing unit and transmits the amplified signal light to the wavelength-multiplexed signal light receiving device via a transmission path;
An optical wavelength division multiplexing transmission system.

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