JP3308148B2 - Optical submarine cable branching device for WDM communication system and WDM optical submarine cable network using the same - Google Patents

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 device and an optical submarine cable network using a wavelength division multiplexing communication system, and more particularly, to an optical submarine cable network capable of transmitting and receiving optical signals equally to each other, and more freely. The present invention relates to an optical submarine cable branching device for a wavelength division multiplexing communication system for realizing a submarine cable network and a wavelength division multiplexing optical submarine cable network using the same.

[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.
There is a configuration as shown in FIG. That is, for example, narrow band rejection filters 44a and 44b for blocking the passage of an optical signal of wavelength λ1 and four optical circulators 44c to 44c.
44f.

The inventor of the present invention attempted to create an optical submarine cable branching device using the optical AD device having such a configuration, and came up with a configuration as shown in FIG. As shown, from the main terminal 41, upstream and downstream main line WDM optical submarine cables 42 and 43 extend,
Each of them is connected to optical submarine cable branching devices 44, 45, 46 at ground 1, ground 2 and ground 3, respectively. Ground 1
Attention is paid to the optical submarine cable branching device 44 for use with the optical submarine cable branching device 44. The device 44 comprises narrow band rejection filters 44a and 44b for blocking the passage of the optical signal of the wavelength λ1 and four optical circulators 44c to 44f. . As a result, the ground 1 is connected from the upstream main line WDM optical submarine cable 42 to the optical circulator 44 c and the narrow band band rejection filter 44.
By the action of a, while receiving the optical signal of wavelength λ1,
Optical circulator 44d and narrow band rejection filter 4
By the operation of 4a, the optical signal of the wavelength λ1 is transmitted to the upstream main line WDM optical submarine cable 42. On the other hand, with respect to the downstream main line WDM optical submarine cable 43, the optical circulator 44f and the narrow band rejection filter 44b receive the optical signal of the wavelength λ1 and the optical circulator 44e and the narrow band rejection filter 44b operate. Thus, the optical signal having the wavelength λ1 is transmitted to the downstream main line WDM optical submarine cable 43. As is apparent from the figure, two optical fiber pairs are used to split an optical signal of one wavelength to the ground 1.

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

[0005]

However, the above-mentioned optical submarine cable branching device uses one optical AD device for the one-way passing path of the main line WDM optical submarine cable, so that one optical submarine cable is used. There is a problem that only one wavelength can be branched by the submarine cable branching device, resulting in poor efficiency. Also, 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 in the branch path connecting the ground, that is, the landing station, and the installation cost of the WDM optical submarine cable network is high. In addition, there is a problem that the relationship between the grounds is a relationship between the master ground and the slave ground, and a free optical submarine cable network cannot be realized.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned problems of the prior art and realize a free optical submarine cable network in which optical signals of a plurality of wavelengths can be branched, and a branch path can be constituted by one optical fiber pair. It is an object of the present invention to provide an optical submarine cable branching device for a wavelength division multiplexing communication system and a wavelength division multiplexing optical submarine cable network using the same.

[0007]

In order to achieve the above object, the present invention is directed to a first, a second, and a third ground-based input optical fiber, and a plurality of wavelengths transmitted from each ground. Reflecting at least one wavelength of the optical signal,
First, second, and third optical filters that transmit optical signals of other wavelengths; and a second optical filter that reflects optical signals of wavelengths reflected by the first optical filter. Means for multiplexing with an optical signal having a wavelength from the ground and leading to an output optical fiber of a third ground, and a third optical signal having a wavelength transmitted through the first optical filter and having transmitted the third optical filter. Means for multiplexing with an optical signal having a wavelength from the ground and leading to an output optical fiber at a second ground, an optical signal having a wavelength from the second ground transmitted through the second optical filter, and the third light Means for multiplexing the optical signal of the wavelength from the third ground reflected from the filter and guiding the multiplexed signal to the output optical fiber of the first ground. According to the present invention, the first, second, and third destinations can equally branch the optical signals of a plurality of wavelengths transmitted from the respective destinations to the other two destinations.

[0008] Further, the present invention is such that each of the three or more optical submarine cable branching devices for a wavelength division multiplex communication system can directly communicate equally between four or more grounds. There is a characteristic in that.

[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 configuration diagram of an embodiment of an optical submarine cable branching device for a three-ground wavelength multiplex communication system according to the present invention. This optical submarine cable branching device for a wavelength division multiplexing communication system branches a wavelength division multiplexed optical signal output from one ground to another ground so that equal communication can be performed between the first, second and third grounds. It is for. In the figure, 1 to 6 are optical circulators, 7 to 10 are narrow band pass filters or narrow band reject filters (hereinafter referred to as optical band pass filters), and as shown, these are optical fibers 1a. , 1b, 2a, 2
b, 3a, 4a, 4b, 5a, 6a and 6b. Also, the ground 1 and the branching device are composed of an input fiber (optical ADD fiber) 11 and an output fiber (optical DRO).
P fiber 12, the ground 2 and the branching device are connected by the input fiber 13 and the output fiber 14, and the ground 3
The branching device is connected to an input fiber 15 and an output fiber 16.

Next, the operation of this embodiment will be described. The wavelengths λ1 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 via the optical fiber 1a. The optical bandpass filter 7 reflects the wavelength λ1 and passes the wavelength λ2. Therefore, the wavelength .lambda.1 is reflected by the optical bandpass filter 7, and is guided again to the optical fiber 1b through the optical circulator 1. Since the optical bandpass filter 9 passes the wavelength λ1, the wavelength λ1 enters the optical fiber 5a, and then passes through the optical circulator 5 to the output fiber 16 of the ground 3. Thus, 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 .lambda.2 from the ground 1 passing through the optical band-pass filter 7 passes through the optical fiber 2a and the optical circulator 2 and enters the output fiber 14 of the ground 2. Thus, the wavelength λ2 output from the ground 1
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, the wavelength λ2 from the ground 2 is obtained by the same operation as described above.
The optical signal having the wavelength λ3 is branched to the ground 1. Similarly, the input fiber 15 from the ground 3
The optical signals of the wavelengths .lambda.1 and .lambda.3 input to the terminals 1 and 2 are branched to ground 1 and ground 2, respectively.

As described above, according to this embodiment, it is possible to branch optical signals of a plurality of wavelengths λ1, λ2; λ2, λ3; λ3, λ1. Further, the branch paths, that is, the input and output optical fibers 11, 12, 13, 14, 15, and 16 can be constituted by one optical fiber pair. Further, it is possible to realize an optical submarine cable network in which 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, the following first and second optical submarine cable branching devices for three-to-ground wavelength division multiplexing communication systems are used to form an optical submarine cable branching device for four-to-ground wavelength division multiplexing communication systems. A first three-ground optical submarine cable branching device for a wavelength division multiplexing communication system includes optical circulators 1 to 6, optical bandpass filters 7a and 8a passing wavelengths λ2 and λ3, and optical bands passing wavelengths λ4 and λ5. It is composed of a pass filter 10a and an optical band pass filter 9 passing through the wavelength λ1. Also,
The second three-ground optical submarine cable branching device for a wavelength division multiplexing communication system includes optical circulators 21 to 26, wavelengths λ3 and λ3.
4 and optical bandpass filters 29 and 30 passing the wavelength λ1.

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

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 passing through 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 that pass through the wavelength λ 1, and is branched to the ground 3. On the other hand, the optical signals of wavelengths .lambda.2 and .lambda.3 that have passed through the optical bandpass filter 7a pass through the optical circulator 2 and pass through the second
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 which passes the wavelengths λ3 and λ4. The optical signal of wavelength .lambda.2 is reflected by the optical bandpass filter 28, enters the optical circulator 24 again, and then enters the optical circulator 26. Next, the light is reflected by the optical band-pass filter 29 passing through the wavelength .lambda.1, and is again branched to the ground 4 through the optical circulator 26. Further, the wavelengths λ3 and λ4
The optical signal enters the optical circulator 23 through the optical band-pass filter 28 and is branched to the ground 2.

As is apparent from the above description, the optical signals of the wavelengths λ1, λ2, λ3 transmitted from the ground 1 are branched to the ground 3, ground 4 and ground 2, respectively. Similarly, the optical signals of the wavelengths λ1, λ4, λ5 transmitted from the ground 3 are
It is branched into ground 1, ground 2, and ground 4, respectively. The optical signals of wavelengths .lambda.1, .lambda.3 and .lambda.4 transmitted from the ground 2 are branched to the ground 4, ground 1 and ground 3, respectively. Further, the wavelengths λ1, λ2, λ transmitted from the ground 4
The optical signal No. 5 is branched to ground 2, ground 1 and ground 3, respectively.

As described above, according to this embodiment, an optical signal having 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 configured. Further, it is possible to realize an optical submarine cable network in which four grounds have an equal relationship. In the first and second embodiments, an optical circulator is used. However, the present invention is not limited to this, and an optical multiplexer / demultiplexer such as an optical coupler may be used.

In the above embodiment, the optical submarine cable branching device for three-to-ground and four-ground wavelength multiplexing communication systems has been described. However, the present invention is not limited to this, and the optical submarine cable for three-to-ground wavelength multiplexing communication systems is described. By using the branching device at three or more locations, it is apparent that a larger optical submarine cable branching device for a wavelength division multiplexing communication system and a wavelength division multiplexing optical submarine cable network using the same can be formed.

[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 performing equal communication between each ground, and a branch path can be constituted by one optical fiber pair. Therefore, a more flexible optical submarine cable network can be realized, the number of optical fibers to be laid can be minimized, and the optical submarine cable network laying cost 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 three-ground wavelength multiplex communication system according to an embodiment of the present invention.

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

FIG. 3 shows 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 band-pass 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 band-pass filter, 11, 13, 15, 17: input optical fiber, 1
2, 14, 16, 18 ... output optical fiber, 7a, 8a,
10a, 27-30: optical band-pass filter, 31, 32
... Fiber grating.

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) H04B 10/00-10/28 H04J 14/00-14/08 G02B 6/293

Claims (5)

(57) [Claims] 1. An optical submarine cable branching device for a wavelength division multiplexing communication system, capable of performing equal communication between first, second and third grounds, wherein each of the first, second and third grounds is provided. The first and second optical fibers are connected to an input optical fiber through which an optical signal is transmitted, and reflect at least one optical signal of a plurality of wavelengths transmitted from each ground and transmit other wavelength optical signals. And a third optical filter; and multiplexing the optical signal of the wavelength reflected by the first optical filter with the optical signal of the wavelength from the second ground reflected by the second optical filter to form a third optical filter. Means for guiding to an output optical fiber connected to the ground, and combining the optical signal having the wavelength transmitted through the first optical filter with the optical signal having the wavelength from the third ground transmitted through the third optical filter. To the output optical fiber connected to the second ground Means for combining an optical signal having a wavelength from a second ground transmitted through the second optical filter and an optical signal having a wavelength from the third ground reflected by the third optical filter; Means for leading to an output optical fiber connected to the ground. 1. An optical submarine cable branching device for a wavelength division multiplexing communication system. 2. The 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 equipment. 3. An optical submarine cable branching device for a wavelength division multiplexing communication system according to claim 1, wherein said optical signal is multiplexed and connected to said first, second and third grounds. The means to guide
An optical submarine cable branching device for a wavelength division multiplexing communication system, comprising: an optical fiber, an optical filter, and an optical circulator. 4. By combining a plurality of optical submarine cable branching devices for three-to-ground wavelength division multiplexing communication system according to claim 1, each ground can be directly communicated equally between four or more grounds. An optical submarine cable branching device for a wavelength division multiplexing communication system. 5. The terminal according to claim 1 or 4, wherein the terminal is a landing station, and all of the terminals can directly communicate with any other cable landing station. WDM optical submarine cable network.