JP2007256612A - Optical multiplexing/demultiplexing module and integrated optical multiplexing/demultiplexing module - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical multiplexing/demultiplexing module and an integrated optical multiplexing/demultiplexing module that can minimize connecting points and the number of components. <P>SOLUTION: A multiplex audio signal $3 is divided into two, with first and second video signals $1, $2 introduced to a rear stage PLC 5 adjacently to each other. The two multiplex audio signals $3 are introduced dividedly to both outer sides of the two video signals $1, $2 on the rear stage PLC 5, with the two video signals $1, $2 multiplexed and bisected using a video multiplexing wavelength independent coupler 6 of the rear stage PLC 5. The multiplex video signals $1, $2 and the multiplex audio signals $3 are multiplexed and bisected respectively by the first and the second video/audio multiplexing wavelength independent couplers 7, 8. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an optical multiplexing / demultiplexing module and an integrated optical multiplexing / demultiplexing module that superimpose and transmit a composite signal of audio and video for two channels, and an optical multiplexing / demultiplexing module that can reduce the number of connection points and parts as much as possible. And an integrated optical multiplexing / demultiplexing module.

  2. Description of the Related Art An optical multiplexing / demultiplexing module is known as an optical device for optical transmission by superimposing two channels of 1 channel signals composed of audio and video. For example, in the field of optical data communication called FTTH (Fiber To The Home), when performing voice data communication in the 1.3 μm band and performing video data communication in the 1.55 μm band, the 1.55 band By providing two input ports, it is possible to provide these two input ports to different communication companies.

  The optical multiplexing / demultiplexing module 31 shown in FIG. 4 introduces the first video signal $ 1 and the second video signal $ 2 into a video multiplexing PLC (Planar Lightwave Circuit) 32 and multiplexes the video signals. By forming a wavelength multiplexing independent coupler (WINC) 33 that multiplexes the first video signal $ 1 and the second video signal $ 2 and branches them into two in the conversion PLC 32 The video multiplexed signal $ 1 $ 2 is branched into two by the video multiplexing PLC 32 and taken out. The audio multiplexed signal $ 3 is passed through the reflection filter 34 for removing the video wavelength band, and emitted from the reflection filter 34. The audio multiplexed signal $ 3 is introduced into the audio adding PLC 35 and is output from the video multiplexing PLC 32. The image multiplexed signal $ 1 $ 2 is distributed to both sides of the audio multiplexed signal $ 3 and introduced into the audio adding PLC 35. The audio adding PLC 35 includes a branching unit 36 that branches the audio multiplexed signal $ 3 into two. A first wavelength-independent add-on coupler 37 for audio addition that multiplexes one of the branched audio multiplex signal $ 3 and the video multiplex signal $ 1 $ 2 introduced on the same side into two branches; The other multiplexed audio multiplexed signal $ 3 and the multiplexed image multiplexed signal $ 1 $ 2 introduced on the same side are combined to form a second added-wavelength independent coupler 38 for adding audio. It is a thing.

  Here, the optical wavelengths of the two video signals $ 1 and $ 2 are 1.55 μm and 1.56 μm. The optical wavelengths of the two audio signals included in the audio multiplexed signal $ 3 are 1.31 μm and 1.49 μm. The reflection filter 34 is a 1.5 μm band reflection filter.

  According to the optical multiplexing / demultiplexing module 31, the 1.55 μm video signal $ 1 and the 1.56 μm video signal $ 2 are multiplexed by the video multiplexing wavelength-independent coupler 33 of the video multiplexing PLC 32. .55 μm and 1.56 μm video multiplexed signal $ 1 $ 2, and this video multiplexed signal $ 1 $ 2 is split into two and emitted and introduced into the audio adding PLC 35. The 1.31 μm and 1.49 μm audio multiplexed signals $ 3 are emitted after the 1.5 μm band is removed by the reflection filter 34 and introduced into the audio adding PLC 35. In the audio adding PLC 35, the audio multiplexed signal $ 3 is branched by the branching unit 36, and the video multiplexed signal $ 1 $ 2 and the audio multiplexed signal $ 3 are respectively obtained by the two audio adding wavelength-independent couplers 37 and 38. Are combined, branched into two, and emitted.

  Note that the wavelength-independent coupler (WINC) has uniform multiplexing / demultiplexing characteristics for a wide range of optical wavelengths including optical wavelengths from 1.31 μm to 1.56 μm.

  As a result, video / audio multiplexed signals $ 1 $ 2 $ 3 obtained by multiplexing two video signals and two audio signals are output # 1, # 2, # 3. Four can be taken out as # 4.

JP-A-8-190026 Japanese Patent Laid-Open No. 10-10346

  The conventional optical multiplexing / demultiplexing module 31 shown in FIG. 4 has many connection points f (circled with a circle) connected by optical fibers. That is, the video multiplexing PLC 32 and the audio adding PLC 35 are connected by two optical fibers. The reflection filter 34 and the audio adding PLC 35 are connected by a single optical fiber. Therefore, three optical fibers are connected, and there are three connection points. Since the optical fibers are connected by fusion, it takes time to work. It should be noted that the optical fibers of the input $ 1, $ 2, $ 3 and the outputs # 1, # 2, # 3. The optical fiber brought from the outside of the optical multiplexing / demultiplexing module 31 like the optical fiber of # 4 is not counted.

  Further, the conventional optical multiplexing / demultiplexing module 31 has a large number of parts. In other words, if counted without the optical fiber, three points of the video multiplexing PLC 32, the audio adding PLC 35, and the reflection filter 34 must be used.

  In other words, the conventional optical multiplexing / demultiplexing module 31 inevitably has an increase in manufacturing cost due to a large number of connection points and an increase in manufacturing / management cost due to a large number of parts.

  Ideally, all optical circuits are formed on a single PLC in order to reduce the number of connection points and parts. However, in order to multiplex a total of three signals, that is, an audio multiplexed signal obtained by multiplexing two audio signals and two video signals, an intersection must be provided during routing of the optical path. At this time, if the optical path is formed of an optical fiber, there is no optical influence even if the optical paths intersect. However, in the PLC, crosstalk at the intersection must be considered. In order to eliminate crosstalk, the crossing angle at the crossing portion needs to be 16 degrees or more. Due to this restriction of the crossing angle, the size of the PLC increases, and the effect of reducing the number of connection points and the number of parts is reduced.

  Accordingly, an object of the present invention is to provide an optical multiplexing / demultiplexing module and an integrated optical multiplexing / demultiplexing module that can solve the above-described problems and can reduce the number of connection locations and the number of parts as much as possible.

To achieve the above object, an optical multiplexing / demultiplexing module of the present invention is an optical multiplexing / demultiplexing module that multiplexes / demultiplexes four optical signals having different wavelengths,
An input port for inputting a multiplexed optical signal in which two of the four optical signals are multiplexed, a branching unit for branching the multiplexed optical signal, and between the input port and the branching unit And a reflection filter for blocking optical signals other than the multiplexed optical signal is formed in the preceding PLC,
A port for inputting an output optical signal from the branching unit, a port for inputting an optical signal other than the multiplexed optical signal among the four optical signals, and the optical signal and the multiplexed optical signal are multiplexed. A plurality of couplers and four ports for outputting an output optical signal obtained by combining the above four optical signals are formed in a rear-stage PLC.

  The optical multiplexing / demultiplexing module according to the present invention includes a first video signal having a first optical wavelength within the video wavelength band and a second video signal having a second optical wavelength within the video wavelength band. And an audio multiplexed signal obtained by multiplexing two audio signals by multiplexing and demultiplexing an audio multiplexed signal obtained by superimposing two audio signals having two optical wavelengths within the audio wavelength band. In the optical multiplexing / demultiplexing module that takes out four, an audio multiplexed signal is introduced into a preceding PLC, and a reflection filter for removing a video wavelength band from the audio multiplexed signal and an output side of the reflecting filter are input to the preceding PLC. And branching out the audio multiplexed signal into two at the preceding PLC and introducing the first video signal and the second video signal to the subsequent PLC adjacent to each other and First stage The two audio multiplexed signals from the LC are distributed and introduced to the outside of the two video signals in the latter stage PLC, and the first video signal and the second video signal are combined into the latter stage PLC. A two-branch wavelength-independent coupler for video multiplexing and one of the video multiplexed signals output from the wavelength-independent coupler for video multiplexing and an audio multiplexed signal introduced on the same side are combined to give 2 The first video / audio multiplexing wavelength-independent coupler to be branched is combined with the other of the video multiplexed signals output from the video multiplexing wavelength-independent coupler and the audio multiplexed signal introduced on the same side. A second wavelength-independent coupler for video and audio multiplexing that is split into two waves is formed.

  The pre-stage PLC may be configured by forming a groove that intersects the waveguide in the middle of the waveguide that guides the audio multiplexed signal to the branching section, and inserting a reflection filter into the groove.

  The wavelength-independent coupler may be configured with an asymmetric X-branch.

Furthermore, the integrated optical multiplexing / demultiplexing module of the present invention is an integrated optical multiplexing / demultiplexing module in which a plurality of n optical multiplexing / demultiplexing modules for multiplexing / demultiplexing four optical signals having different wavelengths are integrated,
An input port for inputting a multiplexed optical signal in which two of the four optical signals are multiplexed, a branching unit for branching the multiplexed optical signal, and between the input port and the branching unit And n sets of reflection filters for blocking optical signals other than the multiplexed optical signal are formed in the pre-integrated PLC,
A port for inputting an output optical signal from the branching unit, a port for inputting an optical signal other than the multiplexed optical signal among the four optical signals, and the optical signal and the multiplexed optical signal are multiplexed. N sets of a plurality of couplers and four ports for outputting an output optical signal obtained by combining the four optical signals are formed in a post-integrated PLC.

  The present invention exhibits the following excellent effects.

  (1) The number of connection points and the number of parts can be reduced as much as possible.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  As shown in FIG. 1, the optical multiplexing / demultiplexing module 1 according to the present invention includes a first video signal $ 1 having a first optical wavelength in the video wavelength band and a second light in the same wavelength band. A second video signal $ 2 having a wavelength and an audio multiplexed signal $ 3 obtained by superimposing two audio signals having two optical wavelengths in the audio wavelength band are combined and demultiplexed to obtain two video signals and In the optical multiplexing / demultiplexing module 1 that extracts four (# 1 to # 4) video / audio multiplexed signals $ 1 $ 2 $ 3 obtained by multiplexing two audio signals, the audio multiplexed signal $ 3 is introduced to the preceding PLC 2 and the preceding The PLC 2 is formed with a reflection filter 3 for removing the video wavelength band from the audio multiplexed signal and a branching unit 4 having the output side of the reflection filter 3 as an input, so that the audio multiplexed signal $ 3 is sent to the preceding PLC 2 Branch out into two and take out the first video signal $ 1 and the second video signal $ 2 are introduced adjacent to each other in the rear stage PLC5, and the two audio multiplexed signals from the previous stage PLC2 are distributed and introduced to both sides of the two video signals in the rear stage PLC5, In the subsequent stage PLC5, a wavelength-independent coupler 6 for video multiplexing that splits the first video signal $ 1 and the second video signal $ 2 into two, and a wavelength-independent coupler for video multiplexing. 1 is a wavelength-independent coupler for video and audio multiplexing 7 that multiplexes one of the video multiplexed signal $ 1 $ 2 output from 6 and the audio multiplexed signal $ 3 introduced on the same side to branch into two. And the other of the video multiplexed signal $ 1 $ 2 output from the video multiplexing wavelength-independent coupler 6 and the audio multiplexed signal $ 3 introduced on the same side are multiplexed into two branches. Wavelength independent coupler 8 for video / audio multiplexing 2 It is obtained by forming a.

  Here, the optical wavelengths of the two video signals $ 1 and $ 2 are 1.55 μm and 1.56 μm. The optical wavelengths of the two audio signals included in the audio multiplexed signal $ 3 are 1.31 μm and 1.49 μm. The reflection filter 3 is a 1.5 μm band reflection filter.

  As shown in the figure, the rear-stage PLC 5 includes an introduction section (input port) for the audio multiplexed signal $ 3, an introduction section for the first video signal $ 1, in order from the input side corresponding to the left side in the figure, in the order from the top side in the figure. The video signal $ 2 introducing unit and the audio multiplexed signal $ 3 introducing unit are arranged, and the optical path of the first video signal $ 1 and the optical path of the second video signal $ 2 from these introducing units are imaged. It is incorporated in the multiplexing wavelength-independent coupler 6, and the optical path of the audio multiplexed signal $ 3 that is closer to the upper side in the drawing and the optical path of the audio multiplexing signal $ 3 that is closer to the upper side in the drawing is the first. And the optical path of the audio multiplexed signal $ 3 closer to the lower side in the figure as well as the one near the lower side of the output side of the wavelength-independent coupler 6 for video and audio multiplexing. Incorporated in the second wavelength-independent coupler 8 for video / audio multiplexing, Extend the output side optical path of the video and audio multiplexing wavelength-dependent coupler 7,8 to the output end corresponding to illustrated the right side is formed a port for output.

  According to the configuration of the latter-stage PLC 5, the first video signal $ 1 and the second video signal $ 2 are introduced adjacent to each other at the input end, and the audio multiplexed signal $ 3 is sandwiched between both outer sides. Therefore, the two video multiplexed signals $ 1 $ 2 output from the video multiplexing wavelength-independent coupler 6 can be combined with the audio multiplexed signals $ 3 of the adjacent optical paths, respectively. Therefore, no intersection is formed in the rear-stage PLC 5.

  Compared with the post-stage PLC 5 and the audio adding PLC 35 in the optical multiplexing / demultiplexing module 31 of FIG. 4, the audio adding PLC 35 introduces the audio multiplexed signal $ 3 into the center of the input end and the video multiplexed signal $ 1 $ 2 as the audio multiplexed signal. Thus, the positional relationship of the optical path through which the signal passes is opposite to that of the rear-stage PLC 5. Further, the rear-stage PLC 5 integrates the video multiplexing PLC 32 and the audio addition PLC 35 and eliminates the branching section 36.

  On the other hand, the front-stage PLC 2 is provided with a reflection filter 3 and a branching section 4. This branching unit 4 is functionally the same as the branching unit 36 provided at the input end of the voice adding PLC 35, but the output of the branching unit 4 is optically transmitted to the subsequent PLC 5 by being placed in the preceding PLC 2. They are guided by the fibers 9a and 9b.

  Due to such a structural difference regarding the arrangement of the optical path and the optical element, the number of connection points f by the optical fiber (X mark) is reduced to two. Of course, as in the prior art, optical fibers with inputs $ 1, $ 2, $ 3 and outputs # 1, # 2, # 3. The optical fiber brought from the outside of the optical multiplexing / demultiplexing module 1 like the optical fiber of # 4 is not counted.

  Further, the number of parts of the optical multiplexing / demultiplexing module 1 is two points, that is, the front-stage PLC 2 and the rear-stage PLC 5.

  As described above, the optical multiplexing / demultiplexing module 1 of the present invention has fewer connection points by optical fibers and fewer parts than the conventional optical multiplexing / demultiplexing module 31. Therefore, manufacturing cost and management cost can be reduced.

  Next, the configuration of the preceding PLC 2 will be described in detail.

  As shown in FIG. 2, the front-stage PLC 2 forms a groove 22 that intersects the waveguide 21 in the middle of the waveguide 21 that guides the audio multiplexed signal $ 3 to the branching section 4, and the reflection filter 3 is placed in the groove 22. Inserted and configured. The groove 22 is formed by dicing or the like and intersects the waveguide 21 at a right angle. The reflection filter 3 is formed in a plate shape having a constant thickness. This reflection filter 3 has outputs # 1, # 2, # 3. This is to prevent the 1.55 μm band light including the video signals $ 1 and $ 2 from going backward to the input terminal of the audio multiplexed signal $ 3 when the # 4 optical fiber is disconnected. A core 23 appears at the end of the preceding PLC 2 that is the output side of the branching section 4.

  Next, a configuration example of a wavelength-independent coupler (WINC) used in the present invention will be described.

  As the video multiplexing wavelength-independent coupler 6, the first video / audio multiplexing wavelength-independent coupler 7, and the second video / audio multiplexing wavelength-independent coupler 8, a so-called 1: 1WINC is used. In 1: 1WINC, input light is output equally to two branches, and the ratio of the output light intensity between the first output and the second output is 1: 1.

  The 1: 1 WINC shown in FIG. 3A is configured with a directional coupler 301. The directional coupler 301 can determine a wavelength-independent wavelength range based on the gap G and the length L of the straight portion. However, it is difficult to achieve wavelength independence in the wide band of 1.31 to 1.56 μm by the directional coupler 301, and it is difficult to make only the wavelength independent of the 1.5 μm band (1.55 to 1.56 μm). Can not. Therefore, the WINC in FIG. 3A can obtain an output ratio of 1: 1 only in the 1.5 μm band.

  The 1: 1 WINC shown in FIG. 3B is a Mach-Zehnder (MZI) type WINC 302. The MZI type WINC 302 is obtained by connecting two directional couplers 303 and 304 and setting two optical path lengths between them to L and L + ΔL. The MZI type WINC can realize wavelength independence in a wide band of 1.31 to 1.56 μm.

  The 1: 1 WINC shown in FIG. 3C is configured by an asymmetric X branch 305. The asymmetric X-branch 305 is an X-branch that intersects a two-input two-output optical waveguide, and the widths W0 and W1 of the two input waveguides are different from each other. The widths W2 of the two output waveguides are equal. The asymmetric X-branch 305 can realize wavelength independence in a wide band of 1.31 to 1.56 μm. Furthermore, the asymmetric X-branch 305 is less sensitive to manufacturing variations (process deviation) than the MZI type WINC 302, and is easier to manufacture than the MZI type WINC 302. Therefore, it is preferable to use the asymmetric X-branch 305 for the video multiplexing wavelength-independent coupler 6, the first video / audio multiplexing wavelength-independent coupler 7, and the second video / audio multiplexing wavelength-independent coupler 8.

  In the above description, the input $ 1, $ 2, and $ 3 are the first video signal $ 1, the second video signal $ 2, and the audio multiplexed signal $ 3. The present invention can be applied to an optical multiplexing / demultiplexing module that multiplexes / demultiplexes four optical signals having different wavelengths.

  Further, in the case where an integrated optical multiplexing / demultiplexing module in which a plurality of, for example, eight optical multiplexing / demultiplexing modules 1 described above are integrated is configured, eight front-stage PLCs 2 and rear-stage PLCs 5 are not collected separately from each other. As shown, the integrated optical multiplexing / demultiplexing module 51 forms a front-stage integrated PLC 52 and a back-stage integrated PLC 53.

  The pre-stage integrated PLC 52 includes an input port 54 for inputting an audio multiplexed signal $ 3 obtained by superimposing two audio signals having different optical wavelengths, a branching unit 55 for branching the audio multiplexed signal $ 3, and these input ports and branching units. 8 sets of reflection filters 56 that block optical signals other than the audio multiplexed signal $ 3. The reflection filter 56 forms one groove intersecting the waveguides of the eight input ports 54 and is inserted into the grooves.

  The post-integrated PLC 53 includes a port 57 for inputting the output optical signal from the branching unit 54, a port 58 for inputting the first and second video signals $ 1 and $ 2 having different optical wavelengths, and the first and second Eight sets of a plurality of couplers 59 for combining the video signals $ 1, $ 2 and the audio multiplexed signal $ 3 and four ports 60 for outputting the output optical signal obtained by combining the four optical signals are integrated. Is formed.

  The upstream integrated PLC 52 and the downstream integrated PLC 53 are connected by an optical fiber. Each optical signal is guided by an optical fiber to the input port 54 of the front-stage integrated PLC 52 and the input port 58 of the rear-stage integrated PLC 53.

It is an optical circuit diagram of the optical multiplexing / demultiplexing module showing one embodiment of the present invention. It is a perspective view of the front | former stage PLC used for the optical multiplexing / demultiplexing module of FIG. (A)-(c) is a block diagram which shows the structural example of 1: 1WINC used for this invention. It is an optical circuit diagram of a conventional optical multiplexing / demultiplexing module. 1 is an optical circuit diagram of an integrated optical multiplexing / demultiplexing module showing an embodiment of the present invention.

Explanation of symbols

1 Optical multiplexing / demultiplexing module 2 Previous PLC
3 Reflective filter 4 Branching part 5 Subsequent PLC
6 Wavelength independent coupler for video multiplexing 7 Wavelength independent coupler for first video / audio multiplexing 8 Wavelength independent coupler for second video / audio multiplexing

Claims (5)

An optical multiplexing / demultiplexing module for multiplexing / demultiplexing four optical signals having different wavelengths,
An input port for inputting a multiplexed optical signal in which two of the four optical signals are multiplexed, a branching unit for branching the multiplexed optical signal, and between the input port and the branching unit And a reflection filter for blocking optical signals other than the multiplexed optical signal is formed in the preceding PLC,
A port for inputting an output optical signal from the branching unit, a port for inputting an optical signal other than the multiplexed optical signal among the four optical signals, and the optical signal and the multiplexed optical signal are multiplexed. An optical multiplexing / demultiplexing module characterized in that a plurality of couplers and four ports for outputting an output optical signal obtained by multiplexing the four optical signals are formed in a post-stage PLC.   A first video signal having a first optical wavelength in the video wavelength band, a second video signal having a second optical wavelength in the video wavelength band, and two lights in the audio wavelength band In an optical multiplexing / demultiplexing module that extracts four video / audio multiplexed signals obtained by multiplexing two video signals and two audio signals by multiplexing / demultiplexing an audio multiplexed signal obtained by superimposing two audio signals having wavelengths. By introducing the multiplexed signal into the preceding PLC, and forming in the preceding PLC a reflection filter for removing the video wavelength band from the audio multiplexed signal and a branching unit having the output side of the reflection filter as an input, The audio multiplexed signal is branched out into two at the preceding PLC, the first video signal and the second video signal are introduced adjacent to each other in the succeeding PLC, and the two audio multiplexed signals from the preceding PLC are input to the above PLC. Introduced separately to both sides of the above-mentioned two video signals to the stage PLC, and after that, the first stage video signal and the second video signal are combined and branched into two for the subsequent stage PLC. A first video / audio multiplexing unit that divides the coupler and one of the video multiplexed signals output from the video multiplexing wavelength-independent coupler and the audio multiplexed signal introduced on the same side into two branches. A second video that is split into two by combining a wavelength-independent coupler and the other multiplexed video signal output from the video multiplexing wavelength-independent coupler and an audio multiplexed signal introduced on the same side. An optical multiplexing / demultiplexing module comprising a wavelength independent coupler for audio multiplexing.   The said front stage PLC forms the groove | channel which cross | intersects this waveguide in the middle of the waveguide which guides an audio | voice multiplexed signal to a branch part, and inserts a reflective filter in this groove | channel, and is comprised. Optical multiplexing / demultiplexing module.   4. The optical multiplexing / demultiplexing module according to claim 2, wherein the wavelength-independent coupler comprises an asymmetric X branch. An integrated optical multiplexing / demultiplexing module in which a plurality of n optical multiplexing / demultiplexing modules for multiplexing / demultiplexing four optical signals having different wavelengths are integrated,
An input port for inputting a multiplexed optical signal in which two of the four optical signals are multiplexed, a branching unit for branching the multiplexed optical signal, and between the input port and the branching unit And n sets of reflection filters for blocking optical signals other than the multiplexed optical signal are formed in the pre-integrated PLC,
A port for inputting an output optical signal from the branching unit, a port for inputting an optical signal other than the multiplexed optical signal among the four optical signals, and the optical signal and the multiplexed optical signal are multiplexed. An integrated optical multiplexing / demultiplexing module, wherein n sets of a plurality of couplers and four ports for outputting an output optical signal obtained by multiplexing the four optical signals are formed in a post-integrated PLC.

Images