JPH09153861A - Optical submarine cable branching device for wavelength multiplex communication system, and waveform multiplex optical submarine cable network using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical submarine cable branching device which can branch the optical signals of plural wavelengths, which can constitute a branching path with a pair of optical fibers and which can realize a free optical submarine cable network. SOLUTION: The title optical submarine cable branching device for wavelength multiplex communication system is provided with optical circulators 1 to 6, optical band pass filters 7 to 10 and the optical fibers connecting them. Light signals whose wavelengths are λ1 and λ2, which are transmitted from ground 1, are transmitted to ground 3 and ground 2. The light signals whose wavelengths are λ2 and λ3, which are transmitted from ground, are transmitted to ground 1 and ground 3. The light signals whose wavelengths are λ1 and λ3, which are transmitted from ground 3, are transmitted to ground 1 and ground 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical submarine cable branching apparatus and an optical submarine cable network using a wavelength division multiplexing communication system, and in particular, it is possible for each ground to transmit and receive optical signals on an equal basis and to provide more free optical signals. The present invention relates to an optical submarine cable branching device for a wavelength division multiplexing communication system and a wavelength multiplexing optical submarine cable network using the submarine cable network for realizing a submarine cable network.

[0002]

2. Description of the Related Art Optical ADD / DROP currently proposed
As an apparatus (hereinafter referred to as an optical AD apparatus), for example, FIG.
44 of FIG. That is, for example, narrow band band stop filters 44a and 44b that block passage of an optical signal of wavelength .lambda.1 and four optical circulators 44c.
44f.

The inventor of the present invention tried to make an optical submarine cable branching device by using the optical AD device having such a structure, and came up with a structure as shown in FIG. As shown in the figure, from the main ground 41, upstream and downstream main line wavelength-multiplexed optical submarine cables 42 and 43 extend,
Each of them is connected to optical submarine cable branching devices 44, 45 and 46 at ground 1, ground 2 and ground 3. Ground 1
Focusing on the optical submarine cable branching device 44, the device 44 is composed of narrow band band stop filters 44a and 44b for blocking the passage of an optical signal of wavelength .lambda.1 and four optical circulators 44c to 44f. . As a result, the ground 1 goes from the upstream main line wavelength division multiplexing optical submarine cable 42 to the optical circulator 44c and the narrow band stop filter 44.
By the action of a, while receiving the optical signal of wavelength λ1,
Optical circulator 44d and narrow band stop filter 4
By the action of 4a, the optical signal of wavelength λ1 is sent to the upstream main line wavelength division multiplexed optical submarine cable 42. On the other hand, with respect to the downstream main line wavelength division multiplexing optical submarine cable 43, the optical circulator 44f and the narrow band band stop filter 44b receive the optical signal of the wavelength λ1 by the action of the optical circulator 44f and the narrow band band stop filter 44b. Thus, the optical signal of wavelength λ1 is transmitted to the downstream main line wavelength division multiplexed optical submarine cable 43. As is apparent from the figure, two optical fiber pairs are used to branch an optical signal of one wavelength to the ground 1.

Although the above description was made with respect to the optical submarine cable branching device 44 for the ground 1, the optical submarine cable branching devices 45 and 46 for the ground 2 and the ground 3 have the same configuration and are similar. Is performed. In addition,
The optical AD device is, for example, “CR Giles and V. Mizrah
i: Low-Loss ADD / DROP Multiplexers for WDM Lightwav
e Networks: IOOC-95 ”.

[0005]

However, since the above-mentioned optical submarine cable branching device uses one optical AD device for the one-sided passage path of the main line wavelength-multiplexed optical submarine cable, one optical AD device is used. There is a problem that the submarine cable branching device can branch only one wavelength, resulting in poor efficiency. Further, the optical submarine cable branching device requires two optical AD devices for one fiber pair, and each optical submarine cable branching device requires one optical fiber pair. There is a problem that at least two optical fiber pairs are required for a branch path connecting to the ground, that is, the landing station, and the laying cost of the wavelength division multiplexing optical submarine cable network becomes expensive. In addition, there is a problem that the relation between the grounds becomes the relation between the main ground and the subground, and it is impossible to realize a free optical submarine cable network.

An object of the present invention is to eliminate the above-mentioned problems of the prior art, realize an optical submarine cable network in which an optical signal of a plurality of wavelengths can be branched, a branching path can be configured with one optical fiber pair. An object of the present invention is to provide an optical submarine cable branching device for a wavelength division multiplexing communication system and a wavelength multiplexing optical submarine cable network using the same.

[0007]

In order to achieve the above-mentioned object, the present invention provides a plurality of wavelengths which are connected to the input optical fibers of each of the first, second and third grounds and which are transmitted from each ground. Reflects at least one wavelength of the optical signal,
First, second and third optical filters transmitting optical signals of other wavelengths, and second optical filters of the wavelengths reflected by the first optical filter are reflected by the second optical filter. Means for combining with the optical signal of the wavelength from the ground and guiding it to the output optical fiber of the third ground, and third means for transmitting the optical signal of the wavelength transmitted through the first optical filter to the third optical filter. Means for combining with the optical signal of the wavelength from the ground and guiding to the output optical fiber of the second ground, the optical signal of the wavelength from the second ground and the third light transmitted through the second optical filter It is characterized in that it comprises means for multiplexing the reflected optical signal of the wavelength from the third ground to the filter and guiding it to the output optical fiber of the first ground. According to the present invention, the first, second and third grounds can equally divide the optical signals of a plurality of wavelengths respectively sent out to the other two grounds.

Further, according to the present invention, by combining a plurality of the optical submarine cable branching devices for the wavelength-division multiplex communication system of three ground points, each ground point can directly communicate with each other evenly among four ground points or more. The point is that it was done.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of an embodiment of an optical submarine cable branching device for a wavelength-division multiplex communication system for three ground according to the present invention. This optical submarine cable branching device for a wavelength division multiplexing system branches a wavelength division multiplexing optical signal output from one ground to another ground so that the first, second and third grounds can communicate equally with each other. It is for. In the figure, 1 to 6 are optical circulators, 7 to 10 are narrowband bandpass filters or narrowband bandstop filters (hereinafter referred to as optical bandpass filters), and as shown, these are optical fibers 1a. 1b, 2a, 2
b, 3a, 4a, 4b, 5a, 6a and 6b. Further, the ground 1 and the branching device are an input fiber (optical ADD fiber) 11 and an output fiber (optical DRO).
P fiber) 12, the ground 2 and the branching device by the input fiber 13 and the output fiber 14, and the ground 3
And the branching device are connected by an input fiber 15 and an output fiber 16.

Next, the operation of this embodiment will be described. The wavelengths λ 1 and λ transmitted from the ground 1 to the input fiber 11
The optical signal 2 passes through the optical circulator 1 and is guided to the optical bandpass filter 7 through the optical fiber 1a. The optical bandpass filter 7 reflects the wavelength λ1 and passes the wavelength λ2. Therefore, the wavelength λ1 is reflected by the optical bandpass filter 7 and again guided to the optical fiber 1b through the optical circulator 1. Since the wavelength λ1 passes through the optical bandpass filter 9, the wavelength λ1 enters the optical fiber 5a, then passes through the optical circulator 5 and enters the output fiber 16 of the ground 3. In this way, the optical signal of wavelength λ1 output from the ground 1 is branched to the ground 3.

On the other hand, the optical signal of wavelength λ2 from the ground 1 which has passed through the optical bandpass filter 7 enters the output fiber 14 of the ground 2 through the optical fiber 2a and the optical circulator 2. In this way, the wavelength λ2 output from the ground 1
The optical signal of is branched to the ground 2. Next, the optical signals of the wavelengths λ2 and λ3 input from the ground 2 to the input fiber 13 pass through the optical circulator 4, and are guided to the optical bandpass filter 8 via the optical fiber 4a. The optical bandpass filter 8 reflects the wavelength λ3 and passes the wavelength λ2. Therefore, by the same operation as above, the wavelength λ2 from the ground 2 is
Optical signal of 1 is branched to the ground 1, and an optical signal of wavelength λ3 is branched to the ground 3. Similarly, from the ground 3 to the input fiber 15
The optical signals of wavelengths λ1 and λ3 input to the are branched to the ground 1 and the ground 2, respectively.

As described above, according to this embodiment, optical signals of a plurality of wavelengths λ1, λ2; λ2, λ3; λ3, λ1 can be branched. Further, the branch paths, that is, the input / output optical fibers 11, 12; 13, 14; 15, 16 can be configured by one optical fiber pair. Further, it is possible to realize an optical submarine cable network in which the three grounds have an equal relationship.

Next, a second embodiment of the present invention will be described with reference to the block diagram of FIG. In this embodiment, an optical submarine cable branching device for a wavelength multiplexing communication system of four grounds is used by using the following first and second optical submarine cable branching devices for a wavelength multiplexing communication system of three grounds. The first optical submarine cable branching device for wavelength-division multiplex communication system for three grounds includes optical circulators 1 to 6, optical bandpass filters 7a and 8a that pass wavelengths λ2 and λ3, and optical bands that pass wavelengths λ4 and λ5. It is composed of a pass filter 10a and an optical bandpass filter 9 that passes the wavelength λ1. Also,
The second optical submarine cable branching device for the wavelength-division multiplex communication system for three grounds is the optical circulators 21 to 26 and the wavelengths λ3 and λ.
It is composed of optical band pass filters 27 and 28 which pass 4 and optical band pass filters 29 and 30 which pass the wavelength .lambda.1.

An optical bandpass filter 7 used in the optical submarine cable branching device for the first three-point wavelength-division multiplex communication system.
As a, 8a, 10a and 9, an optical bandpass filter having the characteristic shown in FIG. 3 (a) can be used. on the other hand,
Optical bandpass filters 27, 28, 2 used in the optical submarine cable branching device for the second three-point wavelength multiplexing communication system
As 9 and 30, optical bandpass filters having the characteristics shown in FIG. 3B can be used. The optical bandpass filter 28 having the characteristics shown in FIG. 3 (b) is composed of, for example, the fiber gratings (optical band stop filters) 31 and 3 shown in FIG.
It can also be created by using 2. As shown, the fiber gratings 31 and 32 reflect the wavelengths λ2 and λ5, respectively, and the wavelengths λ1 and λ3 and λ5, respectively.
Through 4.

Next, the operation of the embodiment shown in FIG. 2 will be described.
From the ground 1 through the input fiber 11 the wavelengths λ1, λ2,
When the optical signals of .lambda.3 are input, these optical signals pass through the optical circulator 1 and enter the optical bandpass filter 7a which passes the wavelengths .lambda.2 and .lambda.3. Therefore, the optical signal of wavelength λ1 is reflected by the optical bandpass filter 7a,
The light passes through the optical circulator 1 again, and further passes through the optical bandpass filter 9, the optical circulator 5, and the optical fiber 16 which pass the wavelength λ 1, and is branched to the ground 3. On the other hand, the optical signals of the wavelengths λ2 and λ3 that have passed through the optical bandpass filter 7a pass through the optical circulator 2 and pass through the second 3
The light enters the optical circulator 24 of the optical submarine cable branching device for the wavelength division multiplexing communication system to the ground, and further enters the optical bandpass filter 28 that passes the wavelengths λ3 and λ4. The optical signal of wavelength λ2 is reflected by the optical bandpass filter 28, enters the optical circulator 24 again, and then enters the optical circulator 26. Then, it is reflected by the optical bandpass filter 29 that passes the wavelength λ 1, and again passes through the optical circulator 26 and is branched to the ground 4. Also, the wavelengths λ3 and λ4
The optical signal of (1) passes through the optical bandpass filter 28, enters the optical circulator 23, and is branched to the ground 2.

As is clear from the above description, the optical signals of the wavelengths λ1, λ2, and λ3 transmitted from the ground 1 are branched into the ground 3, the ground 4, and the ground 2, respectively. Similarly, the optical signals of wavelengths λ1, λ4 and λ5 transmitted from the ground 3 are
It is branched into a ground 1, a ground 2, and a ground 4, respectively. The optical signals of wavelengths λ1, λ3, and λ4 transmitted from the ground 2 are branched into the ground 4, the ground 1, and the ground 3, respectively. Further, the wavelengths λ 1, λ 2, λ transmitted from the ground 4
The optical signals of 5 are branched to ground 2, ground 1, and ground 3, respectively.

As described above, according to this embodiment, optical signals of a plurality of wavelengths λ1, λ2, λ3, etc. can be branched, and a branch path, that is, the input / output optical fibers 11, 12 etc. can be used as one optical fiber pair. Can be configured with. Further, it is possible to realize an optical submarine cable network in which four grounds have an equal relationship. Although the optical circulator is used in the first and second embodiments, the present invention is not limited to this, and an optical multiplexer / demultiplexer such as an optical coupler may be used.

In the above-mentioned embodiment, the optical submarine cable branching device for wavelength-division multiplex communication system for three-to-ground and four-to-ground has been described, but the present invention is not limited to this and the optical submarine cable for wavelength-division multiplex communication system for three-to-ground. It is obvious that by using the branching device at three or more places, a larger optical submarine cable branching device for wavelength division multiplexing communication system and a wavelength multiplexing optical submarine cable network using the same can be constructed.

[0019]

According to the present invention, it is possible to provide an optical submarine cable branching device for a wavelength division multiplexing communication system capable of equally communicating between respective grounds, and a branching path can be constructed by one optical fiber pair. Therefore, a more flexible optical submarine cable network can be realized, the number of optical fibers to be installed can be minimized, and the installation cost of the optical submarine cable network can be significantly reduced. Further, branching of optical signals of a plurality of wavelengths can be realized.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an optical submarine cable branching device for a wavelength-division multiplex communication system for three grounds according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of an optical submarine cable branching device for a multipoint wavelength division multiplexing communication system according to a second embodiment of the present invention.

FIG. 3 is a characteristic diagram of an example of an optical bandpass filter used in the second embodiment.

FIG. 4 is a diagram showing a specific configuration of an optical bandpass filter.

FIG. 5 is a configuration diagram of an example of a conventional optical submarine cable branching device.

[Explanation of symbols]

1 to 6 ... Optical circulator, 7 to 10 ... Optical bandpass filter, 11, 13, 15, 17 ... Input optical fiber, 1
2, 14, 16, 18 ... Output optical fibers, 7a, 8a,
10a, 27 to 30 ... Optical band pass filter, 31, 32
… Fiber grating.

Claims (5)

[Claims] 1. An optical submarine cable branching device for a wavelength division multiplexing communication system, which enables equal communication between the first, second and third grounds, and each of the first, second and third grounds. First and second optical fibers connected to an input optical fiber for transmitting an optical signal from the optical fiber and reflecting optical signals of at least one wavelength out of a plurality of wavelengths transmitted from each ground and transmitting optical signals of other wavelengths. And a third optical filter, and an optical signal having a wavelength reflected by the first optical filter is combined with an optical signal having a wavelength from the second ground reflected by the second optical filter to produce a third optical signal. Means for guiding to an output optical fiber connected to the ground, and an optical signal having a wavelength transmitted through the first optical filter is multiplexed with an optical signal having a wavelength transmitted from the third optical filter through the third optical filter. To the output optical fiber connected to the second ground Means for combining the optical signal of the wavelength from the second ground transmitted through the second optical filter and the optical signal of the wavelength from the third ground reflected by the third optical filter, 1. An optical submarine cable branching device for a wavelength division multiplexing communication system, comprising: a means for guiding the output optical fiber connected to one ground. 2. The optical submarine cable branching device for wavelength division multiplexing communication system according to claim 1, wherein the input optical fiber and the output optical fiber connected to each ground are one fiber pair. Optical submarine cable branching device. 3. The optical submarine cable branching device for wavelength division multiplexing communication system according to claim 1, wherein the output optical fibers combine the optical signals and are connected to the respective grounds of the first, second and third. The means to lead to
An optical submarine cable branching device for a wavelength division multiplexing communication system, each of which is composed of an optical fiber, an optical filter, and an optical circulator. 4. By combining a plurality of optical submarine cable branching devices for the wavelength multiplexing communication system for three grounds according to claim 1, each ground can directly communicate equally among four grounds or more. An optical submarine cable branching device for a wavelength division multiplexing communication system. 5. The landing station according to claim 1 or 4 is a landing station, and any one cable landing station can directly communicate with another cable landing station. WDM optical submarine cable network.