JP2002152131A - Method and device for transmitting optical signal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To transmit an optical signal based on a plurality of serial digital data bidirectionally concerning one optical signal transmitting cable by using the optical signal transmitting cable. SOLUTION: The serial digital data based on digital video signals from a video camera part 11 are converted to the optical signals of a central wavelength for about 1.55 μm, these optical signals are sent through a bidirectional fiber type WDM coupler 17 located on one terminal side of an optical signal transmitting cable 26 to the optical signal transmitting cable 26 and transmitted from one terminal side of the optical signal transmitting cable 26 to the other terminal side, serial digital data based on compound digital signals from a CCU part 12 are converted to the optical signals of a central wavelength for about 1.3 μm, and these signals are sent through a bidirectional fiber type WDM coupler 28 located on the other terminal side of the optical signal transmitting cable 26 to the optical signal transmitting cable 26 and transmitted from the other terminal side of the optical signal transmitting cable 26 to one terminal side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The invention described in the claims of the present application provides, for example, first and second optical signals based on first and second serial digital data, each of which is digital video data. Optical signal transmission method for transmitting bidirectionally between both ends of an optical signal transmission cable and reproducing first and second serial digital data based on the first and second optical signals transmitted through the optical signal transmission cable , And an optical signal transmission device provided for implementing such a method.

[0002]

2. Description of the Related Art Generally, when broadcast program information is recorded by a television broadcast station or the like, an image is taken using a plurality of video cameras. A video signal obtained from each of the plurality of video cameras is transmitted to a camera control unit (Camera) associated with the plurality of video cameras.
Control Unit (CCU), for example, is sent to a relay unit mounted on a vehicle (relay vehicle).

In addition, when an image is taken by a plurality of video cameras, it is necessary for a person who operates each of the video cameras (a cameraman) to know the imaging situation of another video camera. On the image monitor provided in the camera, a reproduced image based on a video signal obtained from another video camera is obtained. Therefore, for example, a video signal obtained from each video camera and sent to the relay unit via the CCU is subjected to predetermined processing in the relay unit, and is supplied from the relay unit to each video camera via the CCU.

[0004] As described above, the video signal obtained from another video camera supplied from the relay unit to each video camera through the CCU does not require a high quality reproduced image based on the video signal for the purpose. Therefore, such a video signal is obtained by subjecting a video signal obtained from another video camera to compression processing or the like, and has a limited transmission capacity and is easily transmitted.
Hereinafter, this video signal is referred to as a return video signal.

Further, various control signals are supplied to each video camera from the CCU as needed.

As described above, between the video camera and the relay unit, the video signal obtained from the video camera is transmitted to the relay unit via the CCU, and the return signal after the relay unit performs a predetermined process. Video signals and control signals as necessary are transmitted from the relay unit to the video camera via the CCU, and between the video camera and the CCU or between the CCU and the relay unit, the video signal and the return video signal and the necessary Bidirectional transmission with the corresponding control signal is performed.

[0007] In recent years, video signals obtained from video cameras have been digitized from the viewpoint of diversifying transmitted information and realizing high quality reproduced images.
A video camera (digital video camera) that generates a digitized video signal, that is, a digital video signal, has been put to practical use. A digital video signal obtained from a digital video camera usually follows a standardized data format. As digital video signals conforming to such a standardized data format, HD digital video signals (HD signals), 4: 2: 2 component digital video signals (D1 signals), 4fsc composite digital video signals (D2 signals), and the like. It has been known.

[0008] Taking the HD signal out of these, the HD signal follows a data format as shown in FIG. 13, for example.

The data format shown in FIG.
A luminance signal data sequence (Y data sequence) representing a luminance signal component in a video signal as shown in FIG. 13A and a color difference signal data representing a color difference signal component in the video signal as shown in FIG. 13B Series (P _B
/ P _R data series), Y data series and P _B
/ Each word data forming each of the P _R data sequence is a 10-bit configuration. That is, each of the Y data sequence and P _B / P _R data sequence is a 10-bit quantized digital signal. FIG. 13A shows a line blanking period in each line period in the Y data series and a portion corresponding to a part of the video data period before and after the line blanking period, and FIG. , P _B /
It has been shown a portion corresponding to a portion of the video data period of the horizontal blanking period and before and after in each line period in the P _R data series.

In the Y data series, immediately before the portion corresponding to each video data period, four words (3FF (Y), 000 (Y), 000) each having a 10-bit configuration.
(Y), XYZ (Y)) are provided, and four words each having a 10-bit structure are provided immediately after a portion corresponding to each video data period. (3FF
(Y), 000 (Y), 000 (Y), XYZ (Y))
Timing reference code data (EAV: Endo
f Active Video) is placed. Similarly, P _B / P _R
Even in the data sequence, immediately before the portion corresponding to each video data period, four words each having a 10-bit configuration (3FF (C), 000 (C), 000 (C), XYZ
(C)), and immediately after the portion corresponding to each video data period, four words (3FF (C), 000 (C),
000 (C), XYZ (C)). Of course, EAV and SAV Each of the in Y data sequence, Y data is arranged in a portion corresponding to the line blanking period in the sequence, also people P _B / P _R data in the sequence of the EAV and SAV husband, P disposed in a portion corresponding to the line blanking period in _B / P _R data sequence.

3FF (Y), 3FF (C), 000
(Y) and 000 (C) are fixed value information displayed in hexadecimal, and XYZ (Y) and XYZ (C) are variable value information displayed in hexadecimal. Identification of ranking period and SAV and EA
V indicates the identification.

Further, is one D1 signal of the digital video signal, C _B, which is the Y data sequence which is a 10-bit word sequence data representing the luminance signal component, a 10-bit word sequence data representing the color difference signal components The / _CR data sequence is subjected to word multiplexing processing, and a predetermined portion of the resulting word multiplexed data sequence is obtained by being replaced by SAV and EAV. SAV and EAV play the role of word synchronization data.

The D1 signal takes the form of 10-bit word string data, and follows the data format as shown in FIG. 14, for example. In FIG.
The line blanking period in each line period of the D1 signal and a portion corresponding to a part of the video data period before and after the line blanking period are shown. In such parts, each of the 10
4 words (3FF0000000000
0, XYZ) are provided, and immediately after a portion corresponding to each video data period, four words (3FF, 000,000,000,000, each having a 10-bit configuration) are provided.
XYZ) is provided. 3FF and 000
Is fixed value information displayed in hexadecimal, and XYZ is 1
Variable value information displayed in hexadecimal, including field identification, field blanking period identification, and SAV
And EAV identification.

If the video signal obtained from each video camera is a digital video signal obtained as an HD signal, a D1 signal, or the like as described above, the return video signal and any necessary control signals are also converted to digital signals. ,
That is, a digital return video signal and a digital control signal as required. Each of the digital video signal, the digital return video signal, and the digital control signal as required is converted into serial digital data when transmitted.

A digital video signal obtained as an HD signal, a D1 signal or the like from each video camera as described above, a digital return video signal and a digital control signal as required are transmitted between the video camera and the CCU or the CCU. In bidirectional transmission between the digital video signal and the relay unit, each of the digital video signal, the return video signal, and the control signal as necessary is converted into serial digital data and converted into an optical signal, and the transmission signal capacity is large. Transmission through an optical signal transmission cable that provides excellent transmission efficiency has been proposed. In such a case, a so-called optical fiber is used as an optical signal transmission cable for connecting each video camera and the CCU or an optical signal transmission cable for connecting the CCU and the relay unit.

The optical fiber forming such an optical signal transmission cable is, for example, a quartz single mode fiber (silica SMF). This quartz SMF is
For example, the core diameter is 10 μm, and the clad diameter is 125 μm.
m has one propagation mode, and has a feature that the transmission frequency band is wide and the propagation loss is kept low. Therefore, it is suitable for high-speed and long-distance communication using optical signals, and is suitable for transmitting optical signals based on digital video signals obtained from a video camera.

The quartz-based SMF causes, for example, attenuation of an optical signal in accordance with the attenuation characteristics shown in FIG.
Causes dispersion of the optical signal according to the dispersion characteristic shown in FIG. The dispersion of an optical signal refers to the spread of the frequency spectrum of the optical signal and the spread of the propagation time or waveform distortion of the optical signal caused by the material and structure of the optical fiber. The attenuation characteristic shown in FIG. 15 shows the minimum attenuation value for light having a wavelength of about 1.3 μm and light having a wavelength of about 1.55 μm. In the dispersion characteristics shown in FIG. 16, the dispersion of light having a wavelength of about 1.3 μm is minimized.

[0018]

As described above, each of the digital video signal obtained from the video camera, the digital return video signal, and the digital control signal as required is converted into serial digital data and converted into an optical signal. Then, in performing bidirectional transmission between the video camera and the CCU or between the CCU and the relay unit using the optical signal transmission cable, between the video camera and the CCU or between the CCU and the relay unit, A plurality of optical signals will be provided for bidirectional transmission. Therefore, according to the conventional method, a plurality of optical signal transmission cables are required between the video camera and the CCU or between the CCU and the relay unit, and a relatively large cable installation cable is required. This requires space and increases costs.

Therefore, the optical signal obtained by converting the digital video signal obtained from each video camera, the digital return video signal, and the digital control signal as needed is converted between the video camera and the CCU or between the video camera and the CCU. An optical signal transmission system that can efficiently perform two-way transmission between the relay unit and the optical signal transmission cable in order to minimize the number of optical signal transmission cables is desired. Thus, no such optical signal transmission system has been found.

In view of the above, the invention described in the claims of the present application uses an optical signal transmission cable to transmit an optical signal based on a plurality of serial digital data to one optical signal transmission cable. Therefore, for example, a digital video signal obtained from a video camera, a digital return video signal, and an optical signal obtained by conversion of a digital control signal as required, and When applied to bidirectional transmission using an optical signal transmission cable between a CCU and a CCU and a relay unit, the bidirectional transmission is performed in order to minimize the number of optical signal transmission cables. Provided is an optical signal transmission method that can be performed efficiently, and an optical signal transmission device used for implementing the method.

[0021]

An optical signal transmission method according to any one of claims 1 to 7 in the claims of the present application provides a method for transmitting first serial digital data to a first serial digital data. A first optical signal having a center wavelength is converted, and the first optical signal is provided with first and second input / output terminals on one end side of a first directional coupling unit and the other end. A first input / output terminal of a first bidirectional fiber-type wavelength-division multiplexing coupler having a third input / output terminal provided on the side, and a first directional coupling unit from the first input / output terminal A first optical signal led to a third input / output terminal through the optical signal transmission cable is transmitted to the optical signal transmission cable from one end to the other end, and the second serial digital data is transmitted to the first center. A second optical signal having a second center wavelength different from the wavelength After converting the second optical signal, a fourth input / output terminal is provided at one end of the second directional coupling unit, and fifth and sixth input / output terminals are provided at the other end. To the fifth input / output end of the second bidirectional fiber-type wavelength-division multiplexing coupler, and is led out from the fifth input / output end to the fourth input / output end through the second directional coupler. The second optical signal transmitted to the optical signal transmission cable is transmitted from the other end to one end, and the first optical signal transmitted to the other end of the optical signal transmission cable is transmitted to the second optical signal transmission cable. A second optical signal which is led from the fourth input / output end of the directional fiber type wavelength division multiplexing coupler to the sixth input / output end through the second directional coupling unit and transmitted to one end of the optical signal transmission cable From the third input / output end of the first bidirectional fiber-type WDM coupler. It is intended to derive the second input and output terminals via the first directional coupler section.

The optical signal transmission apparatus according to any one of claims 8 to 14 in the claims of the present application converts the first serial digital data to the first central wavelength. A first electro-optical conversion unit for converting into a first optical signal; a first input / output terminal provided on one end of the first directional coupling unit; and a third input / output terminal provided on the other end. An output terminal is provided, a first optical signal is supplied to the first input / output terminal, and a first optical signal guided to the third input / output terminal through the first directional coupling unit. A bidirectional fiber type wavelength division multiplexing coupler, a second electro-optical converter for converting the second serial digital data into a second optical signal having a second center wavelength different from the first center wavelength, When a fourth input / output end is provided on one end side of the directional coupling section 2 Fifth and sixth input / output terminals are provided on the other end side, a second optical signal is supplied to the fifth input / output terminal, and the second optical signal is coupled to the second directional coupling. A second bidirectional fiber type wavelength division multiplexing coupler led out to a fourth input / output end through the unit, and a first bidirectional fiber type wavelength division multiplexing coupler led out to a third input / output end of the first bidirectional fiber type wavelength division multiplexing coupler.
Is transmitted from one end to the other end, and is derived from the fourth input / output terminal of the second bidirectional fiber type wavelength division multiplexing coupler to the sixth input / output terminal through the second directional coupling unit. And a second bidirectional fiber type wavelength division multiplexing coupler that is led out to a fourth input / output terminal.
Is transmitted from the other end to the one end, and derived from the third input / output end of the first bidirectional fiber-type wavelength division multiplexing coupler to the second input / output end through the first directional coupling unit. And an optical signal transmission cable.

The optical signal transmission method according to any one of the first to seventh aspects of the present invention, or the eighth to eighth aspects of the present invention. In the optical signal transmission device according to the invention described in any one of the above items 14, the first optical signal having the first center wavelength based on the first serial digital data and the second serial digital data And a second optical signal having a second center wavelength based on the two-way transmission between one end and the other end of the common optical signal transmission cable.

At this time, the first optical signal is transmitted through the first input / output terminal, the first directional coupler, and the third input / output terminal of the first bidirectional fiber type wavelength division multiplexing coupler. The second signal transmitted to one end of the optical signal transmission cable is supplied to one end of the cable and transmitted.
Is derived through a third input / output terminal, a first directional coupler, and a second input / output terminal of the first bidirectional fiber-type wavelength division multiplexing coupler, and the second optical signal is A fifth input / output end, a second directional coupling unit, and a fourth input / output terminal of the second bidirectional fiber type wavelength division multiplexing coupler.
The first optical signal transmitted to the other end of the optical signal transmission cable is supplied to the other end of the optical signal transmission cable through the input / output end of the optical signal transmission cable, and is transmitted to the second bidirectional fiber type. A fourth input / output end of the wavelength multiplexing coupler,
It is led out through the second directional coupling unit and the sixth input / output terminal.

In this manner, the second optical signal derived through the second input / output terminal of the first bidirectional fiber type wavelength division multiplexing coupler is used for, for example, reproduction of second serial digital data. The first optical signal derived through the sixth input / output terminal of the second bidirectional fiber type wavelength division multiplexing coupler is, for example, the first optical signal.
For the reproduction of serial digital data.

The optical signal transmission method or the optical signal transmission apparatus according to the invention described in the claims of the present application is, for example, a digital video signal and a digital return video signal obtained from a video camera, and if necessary. Between the video camera and the CCU or the CC
When applied to bidirectional transmission using an optical signal transmission cable between the U and the relay unit, the optical signal transmission cable is arranged between the video camera and the CCU or between the CCU and the relay unit. Wherein the first serial digital data and the second serial digital data are obtained based on a digital video signal and a digital return video signal obtained from a video camera and a digital control signal as required, respectively. It is said.

Thus, the optical signal obtained by converting each of the digital video signal obtained from the video camera, the digital return video signal, and the digital control signal as required, is output between the video camera and the CCU or between the video camera and the CCU. Bidirectional transmission using an optical signal transmission cable with a relay unit can be performed efficiently in order to minimize the number of optical signal transmission cables.

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example of an optical signal transmission method according to any one of the first to third, sixth and seventh aspects of the present invention. An example of the optical signal transmission device according to any one of claims 8 to 10, 13 and 14 in the claims of the present application is described below.

The example shown in FIG.
Bidirectional between a digital video signal obtained from the video camera unit 11 and a composite digital signal comprising a digital return video signal sent from the CCU unit 12 and a digital control signal as required. It is assumed that transmission is performed.

In FIG. 1, a digital video signal DHD is transmitted from a video camera unit 11. The digital video signal DHD, for example, to form a 20-bit word sequence data obtained by multiplexing process is performed on the Y data sequence and P _B / P _R data series as shown respectively in A and B in FIG. 13 And the word transmission rate is, for example, 74.25 MBps.
It is assumed that.

The digital video signal DHD from the video camera unit 11 is supplied to a parallel / serial (P / S) conversion unit 13. The P / S converter 13 converts the digital video signal DHD, which is 20-bit word string data with a word transmission rate of 74.25 MBps, into a P / S signal.
The digital video signal DHD is converted into serial data by performing an S conversion process, and serial digital data DHS based on the digital video signal DHD is obtained with a bit transmission rate of 74.25 MBps × 20 = 1.485 Gbps.

The serial digital data DHS obtained from the P / S converter 13 is supplied to an electro-optical converter (E / O converter).
14. The E / O converter 14 performs an electro-optical conversion process on the serial digital data DHS.

The E / O converter 14 includes, for example, a laser driver 15 and a 1.55 μm band distributed feedback (DFB) laser diode 16 as shown in FIG. Then, the serial digital data DHS from the P / S conversion unit 13 is supplied to the laser driving unit 15, and a laser driving signal SLD corresponding to the serial digital data DHS is obtained from the laser driving unit 15.
It is supplied to the 5 μm band DFB laser diode 16.

1.55 μm band DFB laser diode 1
6 oscillates in a single wavelength mode and emits a laser beam having a center wavelength of about 1.55 μm as shown in FIG. 3, for example, and the temperature characteristic of the center wavelength is, for example, 0.2 nm / ° C.
It is about. 1.5 when the laser drive signal SLD is supplied
The 5 μm band DFB laser diode 16 emits 1.55 μm band laser light having a center wavelength of approximately 1.55 μm in a state modulated by the laser drive signal SLD.
As a result, the optical signal OHS having a center wavelength of about 1.55 μm based on the serial digital data DHS from the E / O converter 14 has a bit transmission rate of 1.485 Gb.
It is obtained under the condition of ps. This optical signal OHS is supplied to a bidirectional fiber type wavelength division multiplexing coupler (bidirectional fiber type WDM coupler) 17.

Bidirectional fiber type WDM coupler 1
7 has a configuration represented by, for example, equivalent block connections as shown in FIG. In the equivalent block connection shown in FIG. 4, a directional coupling unit 18 is provided, and one end of the directional coupling unit 18 is connected to an input / output end 20 connected via an optical connector 19 and an optical input / output terminal 20. An input / output end 22 connected via a connector 21 is provided, and an input / output end 24 connected via an optical connector 23 is provided on the other end side of the directional coupling section 18. I have. The directional coupling part 18 is a part where the optical fiber connected to the optical connector 19 and the optical fiber connected to the optical connector 21 are mutually connected and connected to the optical connector 23.

Then, an optical signal OHS having a bit transmission rate of 1.485 Gbps and a center wavelength of about 1.55 μm from the E / O converter 14 is transmitted from the input / output terminal 20 through the optical connector 19 to the directional coupling unit. It is led to 18.
In the directional coupling unit 18, the optical signal OHS from the optical connector 19 through the optical fiber is transmitted to the optical connector 23 through the optical fiber formed by mutually coupling the optical fiber from the optical connector 19 and the optical fiber from the optical connector 21. Be guided. As a result, the optical signal OHS that has passed through the directional coupler 18 is guided to the input / output terminal 24 through the optical connector 23. The optical signal OHS guided to the input / output terminal 24 in this way is a bidirectional fiber type WDM.
The light is sent from the coupler 17 and guided to the optical connector 25.

The optical connector 25 connects the bidirectional fiber type WDM coupler 17 and one end of the optical signal transmission cable 26. Thereby, the optical signal OHS from the bidirectional fiber type WDM coupler 17 is transmitted to the optical signal transmission cable 26 through the optical connector 25 from one end thereof. The optical signal transmission cable 26 is, for example,
It is assumed to be formed by quartz-based SMF.

At the other end of the optical signal transmission cable 26, an optical connector 27 for connecting the optical signal transmission cable 26 to a bidirectional fiber type WDM coupler 28 is provided. Thereby,
The optical signal OHS transmitted from one end of the optical signal transmission cable 26 to the optical signal transmission cable 26 through the optical connector 25 is transmitted from one end to the other end of the optical signal transmission cable 26, and bidirectionally transmitted from the other end through the optical connector 27. Fiber type WDM
It is led to the coupler 28.

Bidirectional fiber type WDM coupler 2
8, for example, has a configuration represented by equivalent block connections as shown in FIG. In the equivalent block connection shown in FIG. 5, a directional coupling unit 29 is provided, and an input / output end 31 connected via an optical connector 30 is provided at one end of the directional coupling unit 29. The input / output end 33 connected via the optical connector 32 and the optical connector 3 are connected to the other end of the directional coupling portion 29.
4 and an input / output end 35 connected through the input / output terminal 4. The directional coupling unit 29 is a portion where the optical fiber connected to the optical connector 30 is branched and connected to the optical connector 32 and the optical connector 34, respectively.

The bit transmission rate from the optical connector 27 is set to 1.485 Gbps, and the center wavelength is set to about 1.
An optical signal OHS of 55 μm is guided from the input / output end 31 to the directional coupling unit 29 through the optical connector 30. In the directional coupler 29, the optical signal OHS from the optical connector 30 through the optical fiber is guided to the optical connector 32 through the branched optical fiber. Thereby,
The optical signal OHS that has passed through the directional coupler 29 is led out to the input / output terminal 33 through the optical connector 32. The optical signal OHS guided to the input / output terminal 33 in this manner is sent from the bidirectional fiber type WDM coupler 28,
The light is guided to a photoelectric conversion unit (O / E conversion unit) 36.

In the O / E converter 36, the bit transmission rate is set to 1.485 Gbps, and the center wavelength is set to about 1.5.
The optical signal OHS of 5 μm is subjected to photoelectric conversion, and the bit transmission rate based on the optical signal OHS is set to 1.485 Gbp.
s is reproduced.
Then, the reproduced serial digital data DHS
Is supplied to a serial / parallel (S / P) converter 37.

The S / P converter 37 sequentially forms 20-bit words in the serial digital data DHS having a bit transmission rate of 1.485 Gbps.
/ P conversion processing to obtain serial digital data DH.
S is parallelized, and the word transmission rate is set to 1.485 Gbps / 2 based on the serial digital data DHS.
A digital video signal DHD forming 20-bit word string data with 0 = 74.25 MBps is reproduced.
Then, the digital video signal DHD reproduced in the S / P converter 37 is supplied to the CCU 12.

The CCU 12 sends out a composite digital signal DPM. This composite digital signal D
PM is, for example, a compressed video signal obtained by subjecting a digital video signal sent from a video camera unit different from the video camera unit 11 to data compression processing,
Digital control signals for the video camera unit 11 are multiplexed as necessary to form 10-bit word string data, and the word transmission rate is set to, for example, several MBps. The composite digital signal DPM is a digital video signal DPM transmitted from the video camera unit 11.
It has a smaller transmission capacity than HD.

Composite digital signal D from CUU section 12
The PM is supplied to the P / S converter 41. In the P / S converter 41, a composite digital signal D which is 10-bit word string data with a word transmission rate of several MBps
PM is subjected to P / S conversion processing to obtain a composite digital signal D
PM is converted into serial data, and a composite digital signal DPM
Is obtained assuming that the bit transmission rate is several MBps × 10 = several tens Mbps.

The serial digital data DSM obtained from the P / S converter 41 is supplied to an E / O converter 42. The E / O converter 42 performs an electro-optical conversion process on the serial digital data DSM.

The E / O converter 42 includes, for example, a laser driver 43 and a Fabry-Perot (FP) laser diode 44 in a 1.3 μm band as shown in FIG. Then, the serial digital data DSM from the P / S converter 41 is supplied to the laser driver 43,
The serial digital data DSM from the laser driver 43
Is obtained, and the laser drive signal SLR corresponding to 1.
It is supplied to the 3 μm band FP laser diode 44.

1.3 μm band FP laser diode 44
Oscillates in a multi-wavelength mode, and emits a laser beam having a wavelength spectrum of about 8 nm with a center wavelength of about 1.31 μm as shown in FIG. 7, for example. For example, it is about 0.4 nm / ° C. The 1.3 μm band FP laser diode 44 to which the laser drive signal SLR is supplied emits a 1.3 μm band laser beam having a center wavelength of approximately 1.31 μm in a state modulated by the laser drive signal SLR. , An optical signal OSM having a center wavelength of approximately 1.3 μm based on the serial digital data DPM is obtained at a bit transmission rate of several tens Mbps. This optical signal OSM is a bidirectional fiber type WDM.
It is supplied to the coupler 28.

Bidirectional fiber type WDM coupler 2
8, an optical signal OSM having a bit transmission rate of several tens of Mbps and a center wavelength of approximately 1.3 μm from the E / O conversion unit 42 is transmitted from the input / output terminal 35 shown in FIG. It is guided to the directional coupling unit 28. In the directional coupling unit 28, the optical signal OSM from the optical connector 34 through the optical fiber is
The optical fiber from the optical connector 4 and the optical fiber from the optical connector 32 are guided to the optical connector 30 through an optical fiber formed by mutual connection. Thereby, the directional coupling part 28
Is passed through the optical connector 30 to the input / output terminal 31. Thus, the input / output terminal 31
Is derived from the bidirectional fiber type W
The light is sent from the DM coupler 28 and guided to the optical connector 27.

The optical signal OSM from the bidirectional fiber type WDM coupler 28 is transmitted from the other end to the optical signal transmission cable 26 through the optical connector 27, and is transmitted from the other end to the one end of the optical signal transmission cable 26. , And guided from one end through the optical connector 25 to the bidirectional fiber-type WDM coupler 17.

Bidirectional fiber type WDM coupler 1
7, an optical signal OSM having a bit transmission rate of several tens of Mbps and a center wavelength of approximately 1.3 μm from the optical connector 27 is transmitted from the input / output end 24 shown in FIG. It is guided to the coupling section 18. In the directional coupling section 18, the optical signal OSM from the optical connector 23 through the optical fiber is guided to the optical connector 21 through the branched optical fiber. As a result, the optical signal OSM that has passed through the directional coupler 18 is led out to the input / output end 22 through the optical connector 21. The optical signal OSM guided to the input / output terminal 22 in this manner is sent from the bidirectional fiber type WDM coupler 17 and guided to the O / E converter 45.

In the O / E converter 45, the bit transmission rate is set to several tens Mbps, and the center wavelength is set to approximately 1.3 μm.
The optical signal OSM is subjected to photoelectric conversion, and the optical signal OSM
And reproduces serial digital data DSM having a bit transmission rate of several tens of Mbps based on. Then, the reproduced serial digital data DSM is supplied to the S / P converter 46.

The S / P converter 46 sequentially forms 10-bit words in the serial digital data DSM having a bit transmission rate of several tens of Mbps.
The serial digital data DSM is converted into parallel by performing a conversion process, and the word transmission rate is set to several tens Mbps / 10 = several M based on the serial digital data DSM.
A composite digital signal DPM forming 10-bit word string data of Bps is reproduced. The composite digital signal DPM reproduced in the S / P converter 46
Is supplied to the video camera unit 11.

As described above, in the example shown in FIG. 1, the video camera unit 1 of the optical signal OHS based on the digital video signal DHD obtained by the video camera unit 11
1 to the CCU unit 12 and an optical signal O based on the composite digital signal DPM transmitted from the CCU unit 12.
The transmission of the SM from the CCU unit 12 to the video camera unit 11 is performed using a common optical signal transmission cable 26. Therefore, according to the example shown in FIG. 1, the digital video signals DHD and CHD obtained from the video camera
The video camera unit 11 and the CCU with the optical signal OSM based on the composite digital signal DPM transmitted from the CU unit 12
Bidirectional transmission using the optical signal transmission cable 26 to and from the unit 12 can be performed efficiently in order to minimize the number of optical signal transmission cables.

In the example shown in FIG. 1, the digital video signal DHD obtained by the video camera unit 11 and the composite digital signal DPM transmitted from the CCU unit 12 are relatively large in digital video signal DHD. In view of the relationship that the composite digital signal DPM has a relatively small transmission capacity, the 1.55 μm band DFB laser diode is used to obtain the optical signal OHS based on the digital video signal DHD. It is assumed that the optical signal OHS has a center wavelength of about 1.55 μm. On the other hand, in order to obtain an optical signal OSM based on the composite digital signal DPM, the 1.3 μm band FP is used.
Using a laser diode, the optical signal OSM has a center wavelength of approximately 1.3 μm. 1.3 μm band F
P laser diodes are relatively inexpensive.

By doing so, it is possible to perform optical signal conversion suitable for the transmission of each of the digital video signal DHD and the composite digital signal DPM, and to reduce the cost.

Then, in the example shown in FIG.
When transmitting the composite digital signal DPM transmitted from the CU unit 12 from the CCU unit 12 side to the video camera 11, the optical signal OSM based on the composite digital signal DPM is used.
In which the center wavelength is set to about 1.48 μm instead of the center wavelength being set to about 1.3 μm. It can be proposed as an example of the optical signal transmission device according to the invention described in claim 11 in which the signal transmission method is performed.

In such a modification, the E / O converter 4
2 is, for example, as shown in FIG.
3 and a 1.48 μm band FP laser diode 49. 1.48 μm band FP laser diode 4
9 is, for example, developed as a pumping light source for an optical fiber amplifier, oscillates in a multi-wavelength mode, and has a center wavelength of about 1.48 μm as shown in FIG.
A laser beam having a wavelength spectrum of The 1.48 μm band FP laser diode 49 outputs a laser beam having a center wavelength of approximately 1.48 μm to the laser driving unit 4.
3, the optical signal OSM having a center wavelength of about 1.48 μm based on the serial digital data DSM is output from the E / O converter 42 at a bit transmission rate. At a rate of several tens of Mbps and supplied to the bidirectional fiber-type WDM coupler 28.

Even in such a modification, optical signal conversion suitable for the transmission can be performed for each of the digital video signal DHD and the composite digital signal DPM, and the cost can be reduced.

FIG. 10 shows an example of an optical signal transmission method according to any one of claims 5 to 7 in the claims of the present application. An example of the optical signal transmission device according to the invention described in any one of claims 12 to 14 is shown.

The example shown in FIG.
1 and the CCU unit 52, a video camera unit 51
, And a composite digital signal composed of a digital return video signal sent from the CCU 52 and a digital control signal as required.

In FIG. 10, a digital video signal DD1 is transmitted from a video camera section 51. The digital video signal DD1 is, for example, a D1 signal that forms 10-bit word string data according to a data format as shown in FIG. 14, and has a word transmission rate of, for example, 27 MBps. You.

The digital video signal DD 1 from the video camera section 51 is supplied to a P / S conversion section 53. P /
In the S conversion unit 53, the word transmission rate is set to 27 MB.
The digital video signal DD1 is converted into serial data by subjecting the digital video signal DD1 to serial data by performing P / S conversion processing on the digital video signal DD1, which is 10-bit word string data having ps.
DS, the bit transmission rate is 27 MBps × 10 = 27
Obtained as 0 Mbps.

The serial digital data DDS obtained from the P / S converter 53 is supplied to an E / O converter 54. The E / O conversion unit 54 is, for example, an E / O converter shown in FIG.
It is the same as the O-conversion unit 14, and includes a laser driving unit and 1.
And a 3 μm band FP laser diode.
Then, the serial digital data DDS from the P / S conversion unit 53 is supplied to the laser driving unit, and a laser driving signal corresponding to the serial digital data DDS is obtained from the laser driving unit. Supplied to the diode. As a result, the 1.3 μm band FP laser diode makes the center wavelength approximately 1.3 μm.
The laser light in the μm band is emitted in a state modulated by the laser drive signal, whereby the optical signal ODS having the center wavelength of about 1.3 μm based on the serial digital data DD1 is converted from the E / O converter 54 into a bit. It is obtained under the condition that the transmission rate is 270 Mbps. This optical signal O
The DS is supplied to the bidirectional fiber-type WDM coupler 55.

The bidirectional fiber type WDM coupler 5
5 has a configuration represented by, for example, equivalent block connections as shown in FIG. In the equivalent block connection shown in FIG.
And an input / output end 58 connected via an optical connector 57 and an input / output end 60 connected via an optical connector 59 are provided at one end of the directional coupling section 56. Further, an input / output end 62 connected via an optical connector 61 is provided on the other end side of the directional coupling section 56. The directional coupling portion 56 is a portion where the optical fiber connected to the optical connector 57 and the optical fiber connected to the optical connector 59 are mutually connected and connected to the optical connector 61.

The bit transmission rate from the E / O converter 54 is set to 270 Mbps, and the center wavelength is set to approximately 1.3.
An optical signal ODS of μm is guided from the input / output end 58 to the directional coupling unit 56 through the optical connector 57. In the directional coupling unit 56, the optical signal ODS from the optical connector 57 through the optical fiber is transmitted to the optical connector 61 through the optical fiber formed by mutually coupling the optical fiber from the optical connector 57 and the optical fiber from the optical connector 59. Be guided. Thus, the optical signal ODS that has passed through the directional coupling unit 56 is led out to the input / output terminal 62 through the optical connector 61. The optical signal ODS guided to the input / output terminal 62 in this way is sent from the bidirectional fiber type WDM coupler 55 and guided to the optical connector 63.

The optical connector 63 connects the bidirectional fiber type WDM coupler 55 and one end of the optical signal transmission cable 64. Thereby, the optical signal ODS from the bidirectional fiber type WDM coupler 55 is transmitted to the optical signal transmission cable 64 through the optical connector 63 from one end thereof. The optical signal transmission cable 64 is, for example,
It is assumed to be formed by quartz-based SMF.

At the other end of the optical signal transmission cable 64, an optical connector 65 for connecting the optical signal transmission cable 64 to a bidirectional fiber type WDM coupler 66 is provided. Thereby,
An optical signal ODS sent from one end of the optical signal transmission cable 64 to the optical signal transmission cable 64 through the optical connector 63 is transmitted from one end to the other end of the optical signal transmission cable 64, and bidirectionally transmitted from the other end through the optical connector 65. Fiber type WDM
It is led to the coupler 66.

A bidirectional fiber type WDM coupler 6
6 has a configuration represented by, for example, equivalent block connections as shown in FIG. In the equivalent block connection shown in FIG.
An input / output end 69 connected via an optical connector 68 is provided at one end of the directional coupling section 67, and at the other end of the directional coupling section 67, An input / output terminal 71 connected via an optical connector 70 and an input / output terminal 73 connected via an optical connector 72 are provided. The directional coupling portion 67 is a portion where the optical fiber connected to the optical connector 68 is branched and connected to the optical connector 70 and the optical connector 72, respectively.

The bit transmission rate from the optical connector 65 is set to 270 Mbps, and the center wavelength is set to approximately 1.3 μm.
An optical signal ODS of m is guided from the input / output end 69 to the directional coupling section 67 through the optical connector 68. In the directional coupler 67, the optical signal ODS from the optical connector 68 through the optical fiber is guided to the optical connector 70 through the branched optical fiber. As a result, the optical signal ODS that has passed through the directional coupler 67 is
Through to the input / output terminal 71. The optical signal ODS guided to the input / output terminal 71 in this way is sent from the bidirectional fiber type WDM coupler 66 and
It is led to the conversion unit 74.

In the O / E converter 74, the bit transmission rate is set to 270 Mbps, and the center wavelength is set to approximately 1.3 μm.
The optical signal ODS is subjected to photoelectric conversion to obtain the optical signal ODS.
And reproduces the serial digital data DDS with a bit transmission rate of 270 Mbps based on. Then, the reproduced serial digital data DDS is supplied to the S / P converter 75.

The S / P converter 75 sequentially forms 10-bit words in the serial digital data DDS having a bit transmission rate of 270 Mbps.
Conversion processing is performed to parallelize the serial digital data DDS, and the word transmission rate is set to 270 Mbps / 10 = 27 based on the serial digital data DDS.
The digital video signal DD1 forming 10-bit word string data of MBps is reproduced. And S / P
Digital video signal D reproduced in conversion section 75
D1 is supplied to the CCU unit 52.

The CCU 52 sends out a composite digital signal DPN. This composite digital signal D
PN is, for example, a compressed video signal obtained by subjecting a digital video signal sent from a video camera unit different from the video camera unit 51 to data compression processing.
Digital control signals for the video camera unit 51 are multiplexed as necessary to form 10-bit word string data, and the word transmission rate is set to, for example, several MBps. This composite digital signal DPN is a digital video signal D sent from the video camera unit 51.
It has a smaller transmission capacity than D1.

Composite digital signal D from CUU unit 52
The PN is supplied to the P / S converter 81. In the P / S converter 81, a composite digital signal D which is 10-bit word string data with a word transmission rate of several MBps
PN is subjected to P / S conversion processing to obtain a composite digital signal D
PN is converted into serial data, and a composite digital signal DPN
Is obtained assuming that the bit transmission rate is several MBps × 10 = several tens Mbps.

The serial digital data DSN obtained from the P / S converter 81 is supplied to an E / O converter 82. The E / O converter 82 is, for example, structurally similar to the E / O converter 42 shown in FIG. 6, and includes a laser driver and a 0.83 μm band FP laser diode. You. Then, the serial digital data DSN from the P / S converter 81 is supplied to the laser driver, and the serial digital data DSN is supplied from the laser driver.
And a laser drive signal corresponding to 0.83 μm is obtained.
It is supplied to the m-band FP laser diode.

The FP laser diode in the 0.83 μm band is
Oscillates in a multi-wavelength mode and emits a laser beam having a wavelength spectrum having a center wavelength of about 0.83 μm in a state modulated by a laser drive signal.
From the / O conversion unit 82, the serial digital data DSN
Signal OS whose center wavelength is approximately 0.83 μm based on
N is obtained with the bit transmission rate set to several tens of Mbps. The optical signal OSN is supplied to the bidirectional fiber type WDM coupler 66.

Bidirectional fiber type WDM coupler 6
In No. 6, the bit transmission rate from the E / O conversion unit 82 is set to several tens Mbps, and the center wavelength is set to approximately 0.83 μm.
The optical signal OSN is input / output terminal 73 shown in FIG.
Is guided to the directional coupling part 67 through the optical connector 72. In the directional coupling portion 67, the optical signal OSN from the optical connector 72 through the optical fiber is transmitted to the optical connector 68 through the optical fiber formed by mutually coupling the optical fiber from the optical connector 72 and the optical fiber from the optical connector 70. Be guided. Thereby, the directional coupling part 6
The optical signal OSN that has passed through 7 is led out to the input / output terminal 69 through the optical connector 68. Thus, the input / output terminal 6
9 is sent out of the bidirectional fiber-type WDM coupler 66 to the optical connector 65.
It is led to.

The optical signal OSN from the bidirectional fiber type WDM coupler 66 is transmitted from the other end to the optical signal transmission cable 64 through the optical connector 65, and from the other end to the one end of the optical signal transmission cable 64. , And guided from one end to the bidirectional fiber-type WDM coupler 55 through the optical connector 63.

Bidirectional fiber type WDM coupler 5
5, an optical signal OSN having a bit transmission rate of several tens Mbps and a center wavelength of about 0.83 μm from the optical connector 63 is transmitted from the input / output end 62 shown in FIG. It is guided to the coupling section 56. In the directional coupler 56, the optical signal OSN from the optical connector 61 through the optical fiber is guided to the optical connector 59 through the branched optical fiber. Thereby, the optical signal OSN that has passed through the directional coupling unit 56 is
It is led out to the input / output terminal 60 through the optical connector 59. The optical signal OSN guided to the input / output terminal 60 in this manner
Is transmitted from the bidirectional fiber WDM coupler 55 and guided to the O / E converter 85.

In the O / E converter 85, the bit transmission rate is set to several tens Mbps, and the center wavelength is set to approximately 0.83 μm.
m is subjected to photoelectric conversion on the optical signal OSN
The serial digital data DSN whose bit transmission rate is several tens of Mbps based on N is reproduced. And
The reproduced serial digital data DSN is S / P
It is supplied to the conversion unit 86.

The S / P converter 86 sequentially forms 10-bit words in the serial digital data DSN having a bit transmission rate of several tens of Mbps.
The serial digital data DSN is parallelized by performing a conversion process, and the word transmission rate is set to several tens Mbps / 10 = several M based on the serial digital data DSN.
A composite digital signal DPN forming 10-bit word string data of Bps is reproduced. The composite digital signal DPN reproduced in the S / P converter 86
Is supplied to the video camera unit 51.

As described above, in the example shown in FIG. 10, transmission of the optical signal ODS based on the digital video signal DD1 obtained by the video camera section 51 from the video camera section 51 to the CCU section 52 is performed. The transmission of the optical signal OSN based on the composite digital signal DPN transmitted from the CCU unit 52 from the CCU unit 52 to the video camera unit 51 is performed using a common optical signal transmission cable 64. Therefore, according to the example shown in FIG. 10, the digital video signal DD1 obtained from the video camera
And composite digital signal DP transmitted from CCU unit 52
N and the optical signal OSN based on the video camera unit 51 and C
Bidirectional transmission to and from the CU unit 52 using the optical signal transmission cable 64 can be efficiently performed in order to minimize the number of optical signal transmission cables.

Then, in the example shown in FIG.
The digital video signal DD1 obtained by the video camera unit 51 and the composite digital signal DPN transmitted from the CCU unit 52 have a relatively large transmission capacity for the digital video signal DD1, and the composite digital signal DPN is relatively small. In view of the relationship having the transmission capacity, when obtaining the optical signal ODS based on the digital video signal DD1, the central wavelength of the optical signal ODS is set to approximately 1.3 μm using a 1.3 μm band FP laser diode. On the other hand, in obtaining the optical signal OSN based on the composite digital signal DPN, the central wavelength of the optical signal OSN is set to approximately 0.83 μm by using a 0.83 μm band FP laser diode. 1.3 μm band F
Both the P laser diode and the 0.83 μm FP laser diode are relatively inexpensive.

In this manner, the optical signal conversion suitable for the transmission can be performed for each of the digital video signal DD1 and the composite digital signal DPN, and the cost can be reduced.

[0084]

As is apparent from the above description, the optical signal transmission method according to any one of claims 1 to 7 in the claims of the present application, or the method of claim 1 of the present invention. In the optical signal transmission apparatus according to any one of claims 8 to 14, the first optical signal having the first center wavelength based on the first serial digital data. And a second optical signal having a second center wavelength based on the second serial digital data are bidirectionally transmitted between one end and the other end of the common optical signal transmission cable.

At this time, the first optical signal is transmitted through the first input / output terminal, the first directional coupler, and the third input / output terminal of the first bidirectional fiber type WDM coupler. Is transmitted to one end of the optical signal transmission cable and transmitted to one end of the optical signal transmission cable.
Is derived through a third input / output end, a first directional coupling unit, and a second input / output end of the first bidirectional fiber-type WDM coupler, and the second optical signal is The signal is supplied to the other end of the optical signal transmission cable through the fifth input / output end, the second directional coupling unit, and the fourth input / output end in the second bidirectional fiber-type WDM coupler, and is transmitted. The first optical signal transmitted to the other end of the optical signal transmission cable is transmitted to the fourth input / output terminal, the second directional coupling unit, and the sixth input terminal of the second bidirectional fiber-type WDM coupler. Derived through the output end.

In this manner, the second optical signal derived through the second input / output terminal of the first bidirectional fiber type WDM coupler is used, for example, for reproducing the second serial digital data. The first optical signal led out through the sixth input / output terminal of the second bidirectional fiber-type WDM coupler is used, for example, for reproducing first serial digital data.

The optical signal transmission method or the optical signal transmission apparatus according to the invention described in the above-mentioned claims of the present invention provides, for example, a digital video signal and a digital return video signal obtained from a video camera, and if necessary. The optical signal obtained by converting each of the composite digital signal composed of the digital control signal and the digital signal is converted to a bidirectional transmission using an optical signal transmission cable between the video camera and the CCU or between the CCU and the relay unit. When applied, the optical signal transmission cable must be
The first serial digital data and the second serial digital data are arranged between the CU or the CCU and the relay unit, and the first serial digital data and the second serial digital data are a digital video signal and a composite digital signal obtained from a video camera, respectively. Is obtained on the basis of

Thus, the optical signal obtained by converting each of the digital video signal obtained from the video camera, the digital return video signal, and the composite digital signal comprising the digital control signal as needed is converted into the video signal and the CCU signal. In order to minimize the number of optical signal transmission cables, the bidirectional transmission using the optical signal transmission cable between the CCU and the relay unit is performed.
It can be done efficiently.

[Brief description of the drawings]

FIG. 1 is an example of an optical signal transmission method according to the invention described in any one of claims 1 to 3, 6 and 7 in the claims of the present application;
Claims 8 to 10 in the claims of the present application
FIG. 12 is a block connection diagram illustrating an example of an optical signal transmission device according to the invention described in any one of claims 13 and 14.

FIG. 2 is a block diagram showing a specific configuration example of an E / O conversion unit used in the example shown in FIG. 1;

FIG. 3 shows 1.55 μm used in the specific configuration example of FIG. 2;
FIG. 4 is a characteristic diagram used for describing a band DFB laser diode.

FIG. 4 is a block diagram showing a specific configuration example of a bidirectional fiber type WDM coupler used in the example shown in FIG. 1;

FIG. 5 is a block diagram showing a specific configuration example of a bidirectional fiber type WDM coupler used in the example shown in FIG. 1;

FIG. 6 is a block diagram showing a specific configuration example of an E / O conversion unit used in the example shown in FIG. 1;

FIG. 7 is a characteristic diagram used for explaining a 1.3 μm band FP laser diode used in the specific configuration example of FIG. 6;

FIG. 8 is a block diagram showing a specific configuration example of an E / O conversion unit used in a modification of the example shown in FIG. 1;

FIG. 9 is a characteristic diagram used for explaining a 1.48 μm band FP laser diode used in a modification of the example shown in FIG. 1;

FIG. 10 is a view showing an embodiment of an optical signal transmission method according to the present invention; and FIG. 12 is a view showing an embodiment of an optical signal transmission method according to the present invention. FIG. 16 is a block connection diagram illustrating an example of an optical signal transmission device according to the invention described in any one of (a) to (c).

11 is a block diagram showing a specific configuration example of a bidirectional fiber type WDM coupler used in the example shown in FIG.

12 is a block diagram showing a specific configuration example of a bidirectional fiber type WDM coupler used in the example shown in FIG.

FIG. 13 is a time chart showing a data format of a Y data sequence and a P _B / P _R data sequence forming a digital video signal.

FIG. 14 is a time chart showing a data format of a digital video signal.

FIG. 15 is a characteristic diagram showing an attenuation characteristic of a quartz-based SMF.

FIG. 16 is a characteristic diagram showing dispersion characteristics of a quartz-based SMF.

[Explanation of symbols]

11, 51 ... video camera section, 12, 52 ...
CCU unit, 13, 41, 53, 81 ... P / S conversion unit, 14, 42, 54, 82 ... E / O conversion unit,
15, 43 ... laser driver, 16 ... 1.55
μm band DFB laser diode, 17, 28, 55,
66 ... bidirectional fiber type WDM coupler,
18, 29, 56, 67 ... directional coupling part, 19,
21,23,25,27,30,32,34,57,5
9, 61, 63, 65, 68, 70, 72 ... optical connector, 20, 22, 24, 31, 33, 35, 58,
60, 62, 69, 71, 73...
6, 64 ... optical signal transmission cable, 36, 45, 7
4,85 ... E / O converter, 37,46,75,8
6 ... S / P converter, 44 ... 1.3 μm band FP
Laser diode, 49 ... 1.48 µm band FP laser diode

Claims (14)

[Claims] The first serial digital data is converted into a first optical signal having a first center wavelength, and the first optical signal is transmitted to one end of a first directional coupler. 1st and 2nd
The first input and output terminals of the first bidirectional fiber-type wavelength-division multiplexing coupler having a third input and output terminal provided on the other end side of the first directional coupling unit. The first optical signal which is supplied to an output terminal and led out from the first input / output terminal to the third input / output terminal through the first directional coupling unit is sent out to an optical signal transmission cable. While transmitting from one end to the other end of the optical signal transmission cable, the second serial digital data is converted into a second optical signal having a second center wavelength different from the first center wavelength, A fourth input / output end is provided on one end side of the second directional coupling section, and a fifth and sixth optical signal is supplied to the other end side of the second directional coupling section. A second bidirectional fiber type wavelength division multiplexing coupler having input / output terminals The second optical signal supplied from the fifth input / output terminal to the fourth input / output terminal through the second directional coupling unit to the fourth input / output terminal. The first signal transmitted to the signal transmission cable, transmitted from the other end to the one end, and transmitted to the other end of the optical signal transmission cable.
Out of the optical signal from the fourth input / output terminal of the second bidirectional fiber type wavelength division multiplexing coupler to the sixth input / output terminal through the second directional coupler. The second signal transmitted to one end of the transmission cable
An optical signal transmission method for deriving the optical signal of (1) from the third input / output terminal of the first bidirectional fiber type wavelength division multiplexing coupler to the second input / output terminal through the first directional coupling unit. 2. The method according to claim 1, wherein the first serial digital data is modulated by modulating a laser beam emitted by first laser means for emitting a laser beam having a first center wavelength in accordance with the first serial digital data. 1 optical signal, and modulates the laser light emitted by the second laser means for emitting a laser light having a second center wavelength in accordance with the second serial digital data. 2. The optical signal transmission method according to claim 1, wherein the digital data is converted into a second optical signal. 3. The method according to claim 2, wherein the first laser means is a 1.55 μm band distributed feedback laser diode, and the second laser means is a 1.3 μm band Fabry-Perot laser diode. Optical signal transmission method. 4. The method according to claim 2, wherein the first laser means is a 1.55 μm band distributed feedback laser diode and the second laser means is a 1.48 μm band Fabry-Perot laser diode. Optical signal transmission method. 5. The first laser means is a 1.3 μm band laser diode, and the second laser means is 0.83 μm.
3. The optical signal transmission method according to claim 2, wherein the laser signal is a μm band laser diode. 6. The optical signal transmission method according to claim 3, wherein the first optical signal has a larger transmission capacity than the second optical signal. 7. A second optical signal guided to a second input / output terminal of the first bidirectional fiber type wavelength division multiplexing coupler is subjected to photoelectric conversion processing to reproduce second serial digital data. And performing a photoelectric conversion process on a first optical signal guided to a sixth input / output terminal of the second bidirectional fiber-type wavelength division multiplexing coupler to reproduce first serial digital data. An optical signal transmission method according to claim 1. 8. A first electro-optical converter for converting the first serial digital data into a first optical signal having a first center wavelength; A second input / output terminal is provided, and a third input / output terminal is provided on the other end side of the first directional coupling unit, and the first optical signal is provided at the first input / output terminal. And a first bidirectional fiber-type wavelength-division multiplexing coupler for leading the first optical signal to the third input / output terminal through the first directional coupling unit; and a second serial digital data. A second electro-optical converter for converting the optical signal into a second optical signal having a second central wavelength different from the first central wavelength; a fourth input / output terminal on one end side of the second directional coupler; And the fifth and sixth input / output terminals are provided on the other end side of the second directional coupling portion. The second optical signal is supplied to the fifth input / output terminal, and the second optical signal is led out to the fourth input / output terminal through the second directional coupling unit. And transmitting the first optical signal guided to the third input / output end of the first bidirectional fiber type wavelength division multiplexing coupler from one end to the other end. The second input / output terminal of the second bidirectional fiber type wavelength division multiplexing coupler is led out from the fourth input / output terminal to the sixth input / output terminal through the second directional coupler. The second optical signal guided to the fourth input / output terminal of the second bidirectional fiber-type wavelength division multiplexing coupler is transmitted from the other end to the one end, and the first bidirectional signal is transmitted. Is the third input / output end of the fiber type wavelength division multiplexing coupler The first and the optical signal transmission cable that forms as derived in the second input and output terminals via a directional coupling part, and optical signal transmission apparatus includes a. 9. The method according to claim 1, wherein the first light-to-light conversion unit modulates the laser light emitted by the first laser means for emitting the laser light having the first center wavelength in accordance with the first serial digital data. While converting the first serial digital data into a first optical signal, the second electro-optical converter converts the laser light emitted by the second laser means for emitting a laser light having a second center wavelength into a second optical signal. By modulating according to serial digital data,
9. The optical signal transmission device according to claim 8, wherein said second serial digital data is converted into a second optical signal. 10. The method according to claim 9, wherein the first laser means is a 1.55 μm band distributed feedback laser diode, and the second laser means is a 1.3 μm band Fabry-Perot laser diode. Optical signal transmission equipment. 11. The laser device according to claim 9, wherein the first laser means is a 1.55 μm band distributed feedback laser diode, and the second laser means is a 1.48 μm band Fabry-Perot laser diode. Optical signal transmission equipment. 12. The first laser means is a 1.3 μm band laser diode, and the second laser means is 0.8 μm.
The optical signal transmission device according to claim 9, wherein the optical signal transmission device is a 3 μm band laser diode. 13. The transmission system according to claim 10, wherein the first optical signal has a larger transmission capacity than the second optical signal.
The optical signal transmission device according to any one of the above. 14. A second optical signal which is subjected to photoelectric conversion processing on a second optical signal led out to a second input / output terminal of a first bidirectional fiber type wavelength division multiplexing coupler to reproduce second serial digital data. The first serial digital data is reproduced by performing photoelectric conversion processing on the first optical signal guided to the first photoelectric conversion unit and the sixth input / output terminal of the second bidirectional fiber-type wavelength division multiplexing coupler. The optical signal transmission device according to any one of claims 8 to 14, further comprising a second photoelectric conversion unit that performs the operation.