JPWO2014136320A1 - Optical switch and optical switch expansion method - Google Patents

Abstract

The optical switch (2000) includes a plurality of optical signal dividers (2020) and one switching unit (2100). The switching unit (2100) outputs the optical signal input to the optical signal input unit (2120) from one or more optical signal output units (2140). The optical signal division unit (2020) receives an optical signal from the outside. Each optical signal division unit (2020) is connected to one different optical signal input unit (2120), and can be connected to different optical signal division units (2020) included in other optical switches (2000). is there. The optical signal dividing unit (2020) divides an optical signal input from the outside, and outputs the optical signal to the optical signal input unit (2120) and the optical signal dividing unit (2020) included in another optical switch (2000). To do.

Description

  The present invention relates to an optical switch and an optical switch expansion method.

  In order to cope with the increase in the amount of information communication, the capacity expansion of the optical node is required. In order to expand the capacity of the optical node, it is necessary to increase the number of input / output ports of the optical switch as a core. However, there is a limit to increasing the number of input / output ports included in one optical switch. This is because when the input / output ports of the optical switch are increased, the number of optical switch elements required for switching increases, and the size of the optical switch increases. Specifically, the number of optical switch elements that the optical switch needs to have depends on the number of corresponding paths of the optical node and the number of multiplexed wavelengths of optical signals. For example, an ROADM (Reconfigurable Optical Add Drop Multiplexer) that supports 4-way and 80-wavelength multiplexing assumes (4 × 80) × (4 × 80) × 2≈200,000 when the Add / Drop rate is assumed to be 100%. About one optical switch element is required. Realizing an optical switch in which hundreds of thousands of optical switch elements are combined is not practical in terms of physical size.

  Therefore, a method for expanding the number of input / output ports when viewed from the whole optical switch by combining a plurality of relatively small optical switches has been studied. Patent Document 1 discloses a technique for independently adding an optical switch for input and an optical switch for output by using a three-stage switch. Here, in Patent Document 1, when a path of an optical signal is newly set, an optical switch is combined so that it is not necessary to change the path of another already established optical signal. The optical switch group combined in this way is called a non-block switch.

  In Patent Document 2, an input switch and an output switch are independently added by combining a plurality of small capacity switches used for input or output and a large capacity switch for connecting the small capacity switches. The technology is disclosed.

  Patent Document 3 discloses an optical add / drop device. This optical add / drop device includes an optical switch having a branch port and a through port. The number of branch ports can be increased by connecting a new optical switch to the through port.

JP 2002-152785 A JP-A-4-273737 JP 2005-303730 A

  The present inventor has considered combining a plurality of optical switches so that there is no upper limit to the number of optical switches to be combined and one optical signal input to the optical switch can be output from a plurality of output ports. The optical switch of Patent Document 1 has an upper limit on the number of optical switches that can be added because it is difficult to add a second-stage optical switch that connects the input switch and the output switch. In the optical switch of Patent Document 2, the number of optical switches to be combined is determined by the number of ports of the large capacity optical switch. Here, as described above, it is not realistic from the viewpoint of physical size to increase the number of ports of one optical switch without limit. Therefore, the optical switch of Patent Document 2 has an upper limit on the number of ports of the large capacity optical switch, and as a result, there is an upper limit on the number of ports of the entire optical switch.

  In the optical add / drop device of Patent Document 3, one optical signal input to a group of optical switches connected in parallel can be output only from any one of the branch ports. However, the optical signal input to the optical switch may be a combination of a plurality of optical signals with different destinations. In this case, it is necessary to output one optical signal toward each of a plurality of destinations. Therefore, the optical switch needs to be able to output one input optical signal from a plurality of output ports.

  The present invention has been made in view of the above problems. An object of the present invention is to provide a technique capable of combining any number of optical switches and outputting one optical signal input to the optical switch from a plurality of output ports.

  The optical switch provided by the present invention has switching means. The switching means receives a plurality of optical signal input means to which optical signals are respectively input and one or more optical signal input means, and outputs any one of the input optical signals. A plurality of optical signal output means are provided. Further, the optical switch receives an optical signal from the outside of the optical switch and is connected to any one of the optical signal input means, and any one of a plurality of optical signal dividing means included in the other optical switch. A plurality of optical signal dividing means that can be connected and divide and output an optical signal input from the outside of the optical switch to the connected optical signal input means and optical signal dividing means. Each optical signal splitting unit is connected to a different optical signal input unit, and is connected to a different optical signal splitting unit among a plurality of optical signal splitting units included in other optical switches. This optical switch is the above-described optical switch provided by the present invention.

  The optical switch expansion method provided by the present invention is a method of connecting a first optical switch and a second optical switch. In the optical switch expansion method, each optical signal dividing unit included in the first optical switch is connected to different optical signal dividing units among the plurality of optical signal dividing units included in the second optical switch. A means connection step.

  ADVANTAGE OF THE INVENTION According to this invention, the technique which can combine the arbitrary number of optical switches and can output the one optical signal input into the optical switch from several output ports is provided.

  The above-described object and other objects, features, and advantages will become more apparent from the preferred embodiments described below and the accompanying drawings.

1 is a block diagram illustrating an optical switch according to Embodiment 1. FIG. 6 is a block diagram illustrating an optical switch according to Embodiment 2. FIG. It is a block diagram which shows a unit switch. FIG. 4 is a block diagram illustrating a specific configuration of a 4 × 4 switch. It is a figure which illustrates the combination method of the unit switch which doubles the number of output ports. It is a figure which illustrates the combination method of the unit switch which increases the number of output ports 3 times. It is a figure which illustrates the combination method of the unit switch which increases the number of input ports twice. It is a figure which illustrates the combination method of the unit switch which increases the number of input ports 3 times. It is a figure which illustrates the combination method of the unit switch which doubles the number of input ports and doubles the number of output ports. It is a figure which illustrates the combination method of the unit switch which doubles the number of input ports and increases the number of output ports by 3 times. It is a figure which illustrates the combination method of the unit switch which increases the number of input ports by 3 times, and increases the number of output ports by 2 times. It is a figure which illustrates the combination method of the unit switch which increases the number of input ports by 3 times, and increases the number of output ports by 3 times. It is a figure which shows a mode that the intensity | strength of an optical signal attenuate | damps when a some optical switch is connected. It is a block diagram which shows the optical switch of Embodiment 3 which has a connection switch number acquisition part. It is a figure which illustrates the strength of the optical signal output from each optical switch, when a plurality of optical switches concerning Embodiment 3 are connected. FIG. 10 is a block diagram illustrating an optical switch according to a fourth embodiment. 6 is a diagram illustrating a method of combining optical switches in Embodiment 2. FIG. It is a figure which shows the combination method of the optical switch in Example 3. FIG. FIG. 10 is a block diagram illustrating a ROADM device according to a fourth embodiment. FIG. 10 is a block diagram illustrating a configuration of a unit switch used for a drop TPA in a fourth embodiment. FIG. 10 is another block diagram illustrating the optical switch according to the fourth embodiment. FIG. 10 is a block diagram illustrating a configuration of a unit switch used for an Add TPA according to a fourth embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same reference numerals are given to the same components, and the description will be omitted as appropriate.

[Embodiment 1]
FIG. 1 is a block diagram illustrating an optical switch 2000 according to the first embodiment. In FIG. 1, arrows indicate the flow of optical signals. Here, when a functional component or device having the same function is described collectively, a symbol with a hyphen such as “−a1” is omitted. For example, the optical switch 2000-x and the optical switch 2000-y are collectively referred to as an optical switch 2000. Similarly, the optical signal divider 2020-x1 and the optical signal divider 2020-y1 are collectively referred to as an optical signal divider 2020. In addition, the functional components of the same type included in the same optical switch 2000-x are collectively referred to as an optical signal dividing unit 2020-x and an optical signal input unit 2120-x. The same abbreviations are used in the following block diagrams.

  In FIG. 1, an optical switch 2000-a and an optical switch 2000-b are connected via an optical signal dividing unit 2020. In this way, an optical switch in which a plurality of optical switches 2000 are combined is referred to as an optical switch system.

<Optical signal division unit 2020>
The optical switch 2000 has a plurality of optical signal dividers 2020. In FIG. 1, the optical switch 2000 has N (N ≧ 2) optical signal dividers 2020.

  The optical signal divider 2020 receives an optical signal from the outside of the optical switch 2000. Each optical signal dividing unit 2020 is connected to one different optical signal input unit 2120. Each optical signal divider 2020 can be connected to a different optical signal divider 2020 among the optical signal dividers 2020 included in the other optical switches 2000. Then, the optical signal dividing unit 2020 divides the optical signal input from the outside into two, outputs one optical signal to the optical signal input unit 2120, and transmits the other optical signal to another connected optical signal. The data is output to the optical signal divider 2020.

  Each optical signal divider 2020 functions as an input port of the optical switch system when receiving an optical signal from the outside of the optical switch system. The optical signal divider 2020 functions as an expansion port for increasing the output ports of the optical switch system when receiving an optical signal from another optical signal divider 2020.

<Switching unit 2100>
The optical switch 2000 has one switching unit 2100. The switching unit 2100 includes a plurality of optical signal input units 2120 and a plurality of optical signal output units 2140. The number of optical signal input units 2120 is equal to or greater than the number of optical signal division units 2020. The number of optical signal input units 2120 and the number of optical signal output units 2140 may be the same or different. In FIG. 1, the number of optical signal input units 2120 is N, and the number of optical signal output units 2140 is M (M ≧ 2).

  The optical signal input unit 2120 is connected to any one of the optical signal division units 2020. The optical signal input unit 2120 receives an optical signal from the connected optical signal division unit 2020. The optical signal input unit 2120 outputs an optical signal to any one or more optical signal output units 2140.

  The optical signal output unit 2140 outputs any one of the optical signals input from the optical signal input unit 2120. Accordingly, each optical signal input to the switching unit 2100 via the optical signal input unit 2120 is output from an arbitrary optical signal output unit 2140. In the optical switch 2000 of the first embodiment, the optical signal output unit 2140 functions as an output port for the optical switch 2000 to output an optical signal to the outside.

  The switching unit 2100 is, for example, an optical switch module in which the optical signal input unit 2120 is an input port and the optical signal output unit 2140 is an output port.

  If the switching unit 2100 is a CDC (Colorless, Directionless, Contentionless) compatible switch, the optical switch 2000 is a CDC compatible switch. The CDC compatible switch is, for example, a split / select switch. Also, the CDC compatible switch may be a switch composed of a circular AWG (Arrayed-Waveguide Grating) and a matrix switch.

  The switching unit 2100 is preferably a non-block switch. If the switching unit 2100 is a non-block switch, the entire optical switch 2000 becomes a non-block switch. An optical switch system in which a plurality of optical switches 2000 are combined is also a non-block switch. As a result, the optical switch 2000 can be added without affecting the traffic during service.

<Description of operation>
According to the optical switch 2000 of the first embodiment, the optical signals input to the optical signal dividing units 2020-a1 to aN are the optical signal output units 2140-a1 to aM and the optical signal output units 2140-b1 to bM, respectively. Of these, the light is output from an arbitrary optical signal output unit 2140. The operation of the optical switch 2000 will be described with reference to FIG.

  First, the optical signal 1 input to the optical signal dividing unit 2020-a1 is output to the optical signal input unit 2120-a1. Here, as described above, the optical signal input to the switching unit 2100 via the optical signal input unit 2120 is output from an arbitrary optical signal output unit 2140. Therefore, the optical switch 2000-a can output the optical signal 1 from any one of the optical signal output units 2140-a1 to aM.

  The optical signal divider 2020-a1 also outputs the optical signal 1 to the optical signal divider 2020-b1. The optical signal 1 input to the optical signal dividing unit 2020-b1 is output to the optical signal input unit 2120-b1. Then, the switching unit 2100-b outputs the optical signal 1 from any one of the optical signal output units 2140-b1 to bM as in the case of the optical switch 2000-a. Can do.

  As a result, the optical switch system can output the optical signal 1 from any one of the optical signal output units 2140-a1 to aM and the optical signal output units 2140-b1 to bM.

<Action and effect>
When the optical switch 2000-a is used alone, the number of optical signal output units 2140 that are output ports is M. On the other hand, in the optical switch system in which the optical switch 2000-b is combined with the optical switch 2000-a, the number of optical signal output units 2140 that are output ports increases to 2M. As described above, according to the optical switch 2000 of the present embodiment, the number of output ports can be increased by connecting the optical switches 2000 to each other via the optical signal dividing unit 2020.

  Then, the optical switch 2000-b and another optical switch 2000-c can be further connected by the same method as the method of connecting the optical switch 2000-a and the optical switch 2000-b. This increases the number of output ports of the optical switch system from 2M to 3M. Specifically, the optical signal divided by the optical signal dividing unit 2020-b is divided and output to the optical signal input unit 2120-b and the optical signal dividing unit 2020 included in the optical switch 2000-c. To do. Similarly, the number of output ports of the optical switch system can be increased without an upper limit by sequentially connecting the optical switches 2000. Therefore, according to the optical switch 2000 of the present embodiment, there is no upper limit to the number of optical switches that can be combined. Therefore, after the operation of the optical switch system is started, the optical switch 2000 can be added as necessary.

  Further, as described above, each optical signal input from the outside to the optical signal dividing unit 2020 is output from an arbitrary optical signal output unit 2140. Therefore, according to the optical switch 2000 of the present embodiment, an optical signal input to the optical switch 2000 can be output from an arbitrary output port.

[Embodiment 2]
FIG. 2 is a block diagram illustrating an optical switch 2000 according to the second embodiment. In FIG. 2, arrows indicate the flow of optical signals.

<Optical signal selector 2040>
The optical switch 2000 includes a plurality of optical signal selection units 2040. Each optical signal selection unit 2040 is connected to one different optical signal output unit 2140. The optical signal selection unit 2040 receives an optical signal from the connected optical signal output unit 2140. Furthermore, each optical signal selection unit 2040 can be connected to a different optical signal selection unit 2040 among the optical signal selection units 2040 of other optical switches 2000. The optical signal selection unit 2040 receives an optical signal from the connected optical signal selection unit 2040.

  The optical signal selection unit 2040 outputs one of the optical signal input from the optical signal output unit 2140 and the optical signal input from the other optical signal selection unit 2040. The optical signal selection unit 2040 functions as an output port of the optical switch system when outputting an optical signal to the outside of the optical switch system. The optical signal selection unit 2040 functions as an expansion port for increasing the input ports of the optical switch system when outputting an optical signal to another optical signal selection unit 2040.

<Description of operation>
According to the optical switch 2000 of the second embodiment, the optical signals input to the optical signal dividers 2020-a1 to aN and the optical signal dividers 2020-b1 to bN are the optical signal selectors 2040-a1 to aM. Are output from an arbitrary optical signal selection unit 2040. Hereinafter, a description will be given with reference to FIG.

  The optical signal input to the optical signal division unit 2020-a is output to the optical signal selection unit 2040-a via the switching unit 2100-a. Here, the switching unit 2100-a can output an optical signal input to the optical signal input unit 2120-a from an arbitrary optical signal output unit 2140-a. Therefore, the optical switch 2000 can output the optical signal input to the optical signal dividing unit 2020-a from the arbitrary optical signal selecting unit 2040-a.

  The optical signal input to the optical signal division unit 2020-b is output to the optical signal selection unit 2040-b via the switching unit 2100-b. As in the case of the optical switch 2000, the optical switch 2000-b can output the optical signal input to the optical signal dividing unit 2020-b from an arbitrary optical signal selection unit 2040-b.

  For example, it is assumed that the optical signal input to the optical signal divider 2020-b1 is output from the optical signal selector 2040-b1. The optical signal output from the optical signal selection unit 2040-b1 is input to the optical signal selection unit 2040-a1. Here, the optical signal selection unit 2040-a1 outputs either the optical signal input from the optical signal output unit 2140-a1 or the optical signal input from the optical signal selection unit 2040-b1. Therefore, the optical switch 2000-a is input to the optical signal dividing unit 2020-b1 by causing the optical signal selecting unit 2040-a1 to output the optical signal input from the optical signal selecting unit 2040-b1. The optical signal can be output to the outside.

  Here, as described above, the optical switch 2000-b can output the optical signal input to the optical signal division unit 2020-b from the arbitrary optical signal selection unit 2040-b. The optical signal selection units 2040-b1 to bM are connected to the optical signal selection units 2040-a1 to aM, respectively. Therefore, the optical switch 2000-b changes this optical signal to which optical signal by changing the optical signal selection unit 2040-b that is an output destination of the optical signal input to the optical signal dividing unit 2020-b. It can change whether it outputs from selection part 2040-a.

  For example, it is assumed that the optical signal input from the optical signal dividing unit 2020-b1 to the optical signal input unit 2120-b1 is output via the optical signal output unit 2140-bM. In this case, the optical signal is input to the optical signal selection unit 2040-aM. As a result, the optical signal input to the optical signal divider 2020-b1 is output from the optical signal selector 2040-aM. On the other hand, in the above example, the optical signal input to the optical signal dividing unit 2020-b1 is output from the optical signal selecting unit 2040-a1. Thus, by changing the relationship between the input and output of the switching unit 2100-b, the optical switch system outputs the optical signal input to the optical switch 2000-b from the arbitrary optical signal selection unit 2040-a. can do.

  As described above, the optical switch system includes 2N optical signals that are input to the total of 2N optical signal dividers 2020 including the optical signal dividers 2020-a1 to aN and the optical signal dividers 2020-b1 to bN. Can be output from any optical signal selection unit 2040-a. Here, the optical signal dividing unit 2020 corresponds to an input port in the optical switch system. Therefore, by combining the optical switch 2000-b with the optical switch 2000-a, the number of input ports of the optical switch system can be increased from N to 2N.

<Action and effect>
With the above configuration, according to the optical switch 2000 of the present embodiment, another optical switch 2000 can be combined via the optical signal selection unit 2040. By combining a plurality of optical switches 2000, the number of input ports that receive optical signals from the outside can be increased. Further, the number of output ports can be increased by the same method as in the first embodiment. Therefore, according to the present embodiment, by combining the optical switch 2000, both the output port and the input port can be increased.

<Example 1>
A specific configuration method of the optical switch 2000 and a specific method of combining the optical switches 2000 will be described as a first embodiment.

  FIG. 3 is a block diagram showing a unit switch 3000 in which the optical switch 2000 of the second embodiment is specifically mounted. The left side of FIG. 3 shows the configuration of the unit switch 3000 in detail.

  The unit switch 3000 has four 1: 2 optical splitters 3020. The 1: 2 optical splitter 3020 is a specific implementation of the optical signal divider 2020. The 1: 2 optical splitter 3020 divides an optical signal input from the outside into two, outputs one optical signal to the 1: 2 optical splitter 3020 included in the other unit switch 3000, and outputs the other optical signal. Is output to a 4 × 4 switch 3100 described later.

  The unit switch 3000 has four 2: 1 optical selectors 3040. The 2: 1 optical selector 3040 is a specific implementation of the optical signal selection unit 2040. The 2: 1 optical selector 3040 receives optical signals from the 2: 1 optical selector 3040 included in the other unit switch 3000 and the 4 × 4 switch 3100 included in the unit switch 3000.

  Further, the unit switch 3000 has one 4 × 4 switch 3100. The 4 × 4 switch 3100 specifically includes a switching unit 2100 having four optical signal input units 2120 and four optical signal output units 2140.

  FIG. 4 is a block diagram showing a specific configuration of the 4 × 4 switch 3100. The 4 × 4 switch 3100 has four 1: 4 optical splitters 3120 and four 4: 1 optical selectors 3140. The 1: 4 optical splitter 3120 is a specific implementation of the optical signal input unit 2120. The 4: 1 optical selector 3140 is a specific implementation of the optical signal output unit 2140.

  The unit switch 3000 has an input port 100. The input port 100 is a port through which an optical signal input to the 1: 2 optical splitter passes. The unit switch 3000 has an expansion output port 200. The expansion output port 200 is an optical signal divided by the 1: 2 optical splitter 3020 and is a port through which an optical signal output to the 1: 2 optical splitter 3020 included in another unit switch 3000 passes. . The unit switch 3000 has an output port 300. The output port 300 is a port through which an optical signal output from the 2: 1 optical selector 3040 passes. The unit switch 3000 has an expansion input port 400. The expansion input port 400 is a port through which an optical signal input from the 2: 1 optical selector 3040 included in another unit switch 3000 to the 2: 1 optical selector 3040 included in the unit switch 3000 passes.

  5 to 12 to be described later, the unit switch 3000 is expressed in a simplified manner as shown on the right side of FIG.

  5 to 12 are diagrams showing examples of increasing the input ports or output ports of the optical switch system by combining a plurality of unit switches 3000, respectively. In addition, in order to avoid the figure from becoming complicated, the notation of the expansion output port 200 and the expansion input port 400 that are not used in FIGS.

  FIGS. 5 and 6 show combinations in which output ports are doubled and tripled, respectively. In the optical switch system in which two unit switches 3000 shown in FIG. 5 are combined, the input port is the input port 100-a, and the output ports are the output port 300-a and the output port 300-b. FIG. 5 corresponds to a combination of the optical switch 2000-a and the optical switch 2000-b in FIG. In the optical switch system in which three unit switches 3000 shown in FIG. 6 are combined, the input port is the input port 100-a, and the output ports are the output port 300-a, the output port 300-b, and the output port 300-c. It is.

  FIGS. 7 and 8 show a combination method in which the input ports are doubled and tripled, respectively. In the optical switch system in which two unit switches 3000 shown in FIG. 7 are combined, the input ports are the input port 100-a and the input port 100-b, and the output port is the output port 300-a. FIG. 7 corresponds to a combination of the optical switch 2000-a and the optical switch 2000-b in FIG. In the optical switch system in which three unit switches 3000 shown in FIG. 8 are combined, the input ports are the input port 100-a, the input port 100-b, and the input port 100-c, and the output port is the output port 300-a. It is.

  9 to 12 show combinations in which input ports and output ports are increased. Hereinafter, a detailed description will be given using FIG. 9 as an example.

  In the case of FIG. 9, by combining four unit switches 3000, the input ports and output ports of the optical switch system are each doubled. In this example, the input port 100-a of the unit switch 3000-a and the input port 100-b of the unit switch 3000-b function as input ports of the optical switch system. As shown in FIG. 3, each of the input port 100-a and the input port 100-b has four input ports. Further, the output port 300-a of the unit switch 3000-a and the output port 300-c of the unit switch 3000-c function as output ports of the optical switch system. As shown in FIG. 3, each of the output port 300-a and the output port 300-c has four output ports. Therefore, according to the combination method shown in FIG. 9, there are 8 input ports and 8 output ports in the optical switch system.

  The unit switch 3000-a receives optical signals 1 to 4 from the outside of the optical switch system via the input port 100-a. The unit switch 3000-a outputs optical signals 1 to 4 to the outside of the optical switch system via the output port 300-a.

  The unit switch 3000-a outputs optical signals 1 to 4 to the unit switch 3000-c via the expansion output port 200-a. The unit switch 3000-c receives the optical signals 1 to 4 via the input port 100-c. The unit switch 3000-c outputs optical signals 1 to 4 to the outside of the optical switch system via the output port 300-c. Thus, the optical signals 1 to 4 are output from any output port among the eight output ports.

  The unit switch 3000-b receives optical signals 5 to 8 from the outside of the optical switch system via the input port 100-b. The unit switch 3000-b outputs optical signals 5 to 8 to the unit switch 3000-a via the output port 300-b. The unit switch 3000-a receives the optical signals 5 to 8 through the expansion input port 400-a. The unit switch 3000-a outputs optical signals 5 to 8 to the outside of the optical switch system via the output port 300-a.

  The unit switch 3000-b outputs optical signals 5 to 8 to the unit switch 3000-d via the expansion output port 200-b. The unit switch 3000-d receives the optical signals 5 to 8 through the input port 100-d. The unit switch 3000-d outputs optical signals 5 to 8 to the unit switch 3000-c via the output port 300-d. The unit switch 3000-c receives the optical signals 5 to 8 through the expansion input port 400-c. The unit switch 3000-c outputs optical signals 5 to 8 to the outside of the optical switch system via the output port 300-c. As described above, the optical signals 5 to 8 are output from any of the eight output ports.

  As described above, each of the optical signals input from the eight input ports is output from an arbitrary output port among the eight output ports. Therefore, by combining four unit switches 3000 as shown in FIG. 9, the number of input ports and output ports can each be doubled.

  10-12, the input port and the output port are increased by the same method. FIG. 10 shows a combination method in which the number of input ports is doubled and the number of output ports is tripled. In the optical switch system shown in FIG. 10, the input ports are the input port 100-a and the input port 100-b, and the output ports are the output port 300-a, the output port 300-c, and the output port 300-e.

  FIG. 11 shows a combination method in which the number of input ports is tripled and the number of output ports is doubled. In the optical switch system shown in FIG. 11, the input ports are the input port 100-a, the input port 100-b, and the input port 100-c, and the output ports are the output port 300-a and the output port 300-d.

  FIG. 12 shows a combination method in which the number of input ports and the number of output ports are each tripled. In the optical switch system shown in FIG. 12, the input ports are the input port 100-a, the input port 100-b, and the input port 100-c, and the output ports are the output port 300-a, the output port 300-d, and the output. Port 300-h.

  Here, as shown in FIGS. 10 and 11, the number of input ports may be different from the number of output ports. Thus, according to the optical switch 2000 of the second embodiment, the number of input ports and the number of output ports can be increased independently.

  Further, as shown in the first embodiment, by combining optical switches 2000 mounted with the same configuration, it is possible to make only one type of optical switch 2000 to be manufactured. Thereby, in the manufacture of the optical switch 2000, a merit of scale can be expected. Further, by reducing the scale of one optical switch as in the unit switch 3000 described above, the yield at the time of manufacturing the optical switch can be improved.

[Embodiment 3]
In the optical switch 2000 according to the third embodiment, the optical signal dividing unit 2020 uses the intensity of the optical signal output to the optical signal dividing unit 2020 included in the other optical switch 2000 to allow the optical signal to pass therethrough. It is determined according to the number of This will be described in detail below.

  The optical signal dividing unit 2020 of the optical switch 2000 divides the input optical signal into the optical signal input unit 2120 and the optical signal dividing unit 2020 of another optical switch, and outputs them. Therefore, when the optical signal passes through the optical signal dividing unit 2020, the intensity of the optical signal becomes weak.

  Hereinafter, this will be described in detail with reference to FIG. FIG. 13 is a diagram illustrating how the intensity of an optical signal is attenuated when a plurality of optical switches 2000 are connected. In order to avoid complication of the figure, in FIG. 13, the optical switch 2000 is represented by the same method as the abbreviation notation used in the first embodiment. Specifically, the input port 100 is a port through which an optical signal input to the optical signal dividing unit 2020 passes. The expansion output port 200 is a port through which an optical signal that is divided by the optical signal divider 2020 and that is output to the optical signal divider 2020 included in another optical switch 2000 passes. The output port 300 is a port through which an optical signal output by the optical signal output unit 2140 or the optical signal selection unit 2040 passes. In addition, although the description similar to the abbreviation used in Example 1 is used, the optical switch 2000 of Embodiment 3 may not include the optical signal selection unit 2040.

  In FIG. 13, an optical switch 2000-a and an optical switch 2000-b, an optical switch 2000-b and an optical switch 2000-c, and an optical switch 2000-c and an optical switch 2000-d are connected. Each optical switch 2000 receives an optical signal via the input port 100. Here, the optical signal dividing unit 2020 divides the input optical signal into two optical signals having the same strength, and each optical signal is divided into another optical signal dividing unit 2020 and an optical signal input unit 2120. Output. Further, it is assumed that the intensity of an optical signal input from the outside is X.

  First, the optical signal dividing unit 2020-a included in the optical switch 2000-a divides the input optical signal, and the optical signal having the intensity (1/2) X is transmitted to the optical signal input unit 2120-a and the optical signal The signal is output to the signal dividing unit 2020-b. Next, the optical signal dividing unit 2020-b further divides the optical signal having the intensity (1/2) X, and the optical signal having the intensity (1/4) X is combined with the optical signal input unit 2120-b. The data is output to the optical signal dividing unit 2020-c. Then, the optical signal dividing unit 2020-c divides the optical signal having the intensity (1/4) X, and converts the optical signal having the intensity (1/8) X into the optical signal input unit 2120-c and the optical signal. The data is output to the dividing unit 2020-d. Accordingly, the strengths of the optical signals output from the optical switch 2000-a, the optical switch 2000-b, the optical switch 2000-c, and the optical switch 2000-d are (1/2) X and (1/4) X, respectively. , (1/8) X, (1/16) X. As described above, the intensity of the optical signal becomes weaker as the number of optical signal dividing units 2020 that pass therethrough increases.

  Therefore, the optical signal dividing unit 2020 of this embodiment determines an optical signal to be output to another optical signal dividing unit 2020 according to the number of optical signal dividing units 2020 through which the optical signal passes. By doing so, the optical switch 2000 reduces the degree to which the intensity of the optical signal passing through the optical signal dividing unit 2020 is attenuated. As a result, the optical signal output from the switching unit 2100 after passing through a small number of optical signal dividing units 2020 and the intensity of the optical signal output from the switching unit 2100 after passing through a large number of optical signal dividing units 2020 The difference of becomes smaller. Thereby, according to this embodiment, the difference in the intensity of the optical signal output from the switching unit 2100 to the outside of the optical switch 2000 is reduced.

  For example, the optical signal dividing unit 2020 of the present embodiment divides the optical signal so that the intensity of the optical signal input to each optical signal input unit 2120 is equal. In this case, for example, the optical switch 2000 has a configuration shown in FIG. In FIG. 14, solid arrows indicate the flow of optical signals, and dotted arrows indicate the flow of information. This will be described in detail below.

<Connection Switch Number Acquisition Unit 2050>
The optical switch 2000 illustrated in FIG. 14 includes a connection switch number acquisition unit 2050. The connection switch number acquisition unit 2050 includes a maximum number of optical signal division units 2020 including the optical signal division unit 2020 as the optical signal output from the optical signal division unit 2020 to another optical signal division unit 2020. To get through. Hereinafter, the number of switches acquired by the connection switch number acquisition unit 2050 is expressed as Ns. For example, in the case of FIG. 13, the connection switch number Ns acquired by the connection switch number acquisition unit 2050-a is four. The connection switch number Ns acquired by the connection switch number acquisition unit 2050-b is three.

  There are various methods for the connection switch number acquisition unit 2050 to acquire the number of connection switches. For example, the connection switch number acquisition unit 2050 receives a manual input of the number of connection switches. In addition, for example, the connection switch number acquisition unit 2050 acquires the number of connection switches by operating as follows.

  First, the connection switch number acquisition unit 2050 sets the number of connection switches to 1 when the optical signal division unit 2020 does not output an optical signal to another optical signal division unit 2020. In the example of FIG. 13, the number of connection switches of the connection switch number acquisition unit 2050-d is 1. In addition, the connection switch number acquisition unit 2050 outputs an optical signal to the optical signal division unit 2020 and connects the connection switch number acquisition unit 2050 to a connection switch number acquisition unit 2050 included in another optical switch 2000. Output the number of switches. In the case of FIG. 13, for example, the connection switch number acquisition unit 2050-d outputs the number of connection switches to the connection switch number acquisition unit 2050-c.

  The connection switch number acquisition unit 2050 to which the connection switch number is input from the other connection switch number acquisition unit 2050 sets the number obtained by adding 1 to the input connection switch number as its own connection switch number. For example, the connection switch number acquisition unit 2050-c acquires a connection switch number of 1 from the connection switch number acquisition unit 2050-d. Then, the connection switch number acquisition unit 2050-c adds 1 to 1 which is the acquired number of connection switches, and sets its number of connection switches to 2. Similarly, the connection switch number acquisition unit 2050-b included in the optical switch 2000-b acquires the number of connection switches of 2, and adds 1 to the connection switch number to set its own number of connection switches to 3.

<Optical signal division unit 2020>
The optical signal dividing unit 2020 divides the optical signal according to the following mathematical formula 1. In Equation 1, Pi represents the strength of the optical signal input to the optical signal dividing unit 2020. Pd represents the strength of the optical signal output from the optical signal divider 2020 to the other optical signal divider 2020. Ps represents the strength of the optical signal output from the optical signal dividing unit 2020 to the optical signal input unit 2120.

  When each optical signal dividing unit 2020 divides the optical signal according to Equation 1, the intensity of the optical signal Ps output from each optical signal dividing unit 2020 to the optical signal input unit 2120 becomes Pi / Ns. Therefore, optical signals having equal strength are output from all the switching units 2100.

  FIG. 15 is an example in the case where the optical signal dividing unit 2020 outputs an optical signal having a strength according to the formula shown in Equation 1 in the same connection situation as FIG. The intensity of the optical signal output from the output port is all 1/4 the intensity of the input optical signal.

  There are various methods by which the optical signal dividing unit 2020 obtains the number of connected switches. For example, the optical signal dividing unit 2020 acquires information indicating the number of connected switches from the connected switch number acquiring unit 2050. In addition, for example, the optical signal division unit 2020 may receive the number of connection switches output from the connection switch number acquisition unit 2050. Further, the optical signal dividing unit 2020 may acquire the number of connection switches stored in a place other than the connection switch number acquisition unit 2050 by the connection switch number acquisition unit 2050. Further, the optical signal dividing unit 2020 may accept a manual setting of the number of connection switches.

<Action and effect>
According to the present embodiment, an optical signal output from the switching unit 2100 after passing through a small number of optical signal dividers 2020 and an optical signal output from the switching unit 2100 after passing through a large number of optical signal dividers 2020. The difference from the signal strength is reduced. As a result, an apparatus that receives an optical signal from an optical switch system in which a plurality of optical switches 2000 are combined can receive an optical signal having the same strength regardless of which optical switch 2000 is included in the optical switch system. .

  Here, if the intensity of the optical signal output from the optical switch 2000 is weak, a device that has received the optical signal may not be able to extract information included in the optical signal. Therefore, the convenience of the optical switch system is lowered. As described above, according to the present embodiment, since the difference in the intensity of the optical signal output from each optical switch 2000 is small, the convenience of the optical switch system in which the optical switch 2000 is combined is improved.

[Embodiment 4]
The optical switch 2000 of Embodiment 4 is represented by FIG. 16 or FIG.

<Optical signal amplifier 2060>
The optical signal dividing unit 2020 of the fourth embodiment is connected to an optical signal dividing unit 2020 included in another optical switch 2000 via an optical signal amplifying unit 2060. The optical signal amplifier 2060 amplifies the intensity of the optical signal input from the optical signal divider 2020 and outputs the amplified signal to another optical signal divider 2020. The optical signal amplifier 2060 may be provided inside the optical switch 2000 or may be provided outside the optical switch 2000. FIG. 16 shows the optical switch 2000 when the optical signal amplifying unit 2060 is provided inside the optical switch 2000. FIG. 21 shows the optical switch 2000 when the optical signal amplifying unit 2060 is provided outside the optical switch 2000.

  As described above, in the optical switch 2000 of the first and second embodiments, the intensity of the optical signal becomes weaker as it passes through many optical signal dividing units 2020. Therefore, the optical switch 2000 according to the fourth embodiment amplifies the intensity of the optical signal output from the optical signal divider 2020 to another optical signal divider 2020 using the optical signal amplifier 2060.

  For example, it is assumed that the optical signal dividing unit 2020 divides an input optical signal into two optical signals having equal strength. Here, let X be the intensity of the original optical signal. In this case, an optical signal having intensity (1/2) X is input to the optical signal amplifying unit 2060. For example, the optical signal amplification unit 2060 amplifies the input optical signal to twice the intensity. By doing so, an optical signal having an intensity X is input to another optical signal dividing unit 2020. In this way, an optical signal having an intensity X is input to all the optical signal dividers 2020. Therefore, the intensity of the optical signal output from each switching unit 2100 is all (1/2) X. Note that the degree to which the optical signal amplification unit 2060 amplifies the optical signal is not limited to twice.

  The optical signal amplification unit 2060 may be provided in common for all the optical signal division units 2020 or may be provided for each optical signal division unit 2020.

<Action and effect>
According to this embodiment, the optical signal output from the optical signal divider 2020 to another optical signal divider 2020 is amplified by the optical signal amplifier 2060. The difference between the optical signal output to the outside after passing through a small number of optical signal dividing units 2020 and the intensity of the optical signal output to the outside after passing through a large number of optical signal dividing units 2020 is reduced. Thereby, the convenience and reliability of the optical switch 2000 are improved.

<Example 2>
When combining a plurality of optical switches 2000, an optical switch 2000 having the optical signal amplifying unit 2060 and an optical switch 2000 not having the optical signal amplifying unit 2060 may be combined. A specific example in which the optical switch 2000 having the optical signal amplifier 2060 and the optical switch 2000 not having the optical signal amplifier 2060 are combined will be described as a second embodiment.

  Let X be the intensity of an optical signal input to the optical signal divider 2020 from the outside. The optical signal dividing unit 2020 divides the input optical signal into two equal strengths, and each of the optical signal input unit 2120 and the optical signal dividing unit 2020 has an intensity (1/2) X optical signal. Is output.

  As described above, if the intensity of the optical signal output from the optical signal output unit 2140 is weak, there is a possibility that information cannot be extracted from the optical signal in the device that has received the optical signal output from the optical signal output unit 2140. Thus, in this embodiment, it is assumed that the intensity of the optical signal output from the optical signal output unit 2140 must be (1/4) X or more.

  FIG. 17 is a diagram illustrating changes in the intensity of the optical signal in the second embodiment. In FIG. 17, the optical switch 2000-a has an optical signal amplifier 2060, and the optical switch 2000-b does not have an optical signal amplifier 2060. In the second embodiment, it is assumed that the optical signal amplification unit 2060 amplifies the intensity of the optical signal four times.

  In the second embodiment, the optical switch 2000-a divides an optical signal having an intensity X input from the input port 100-a. Then, an optical signal having an intensity (1/2) X is output from the output port 300-a and the expansion output port 200-a. Next, the optical switch 2000-b divides the optical signal input from the input port 100-b into an optical signal having intensity (1/4) X. As a result, an optical signal having an intensity (1/4) X is output from the output port 300-b. In the optical switch 2000-b, the optical signal amplification unit 2060 amplifies the intensity of the optical signal having the strength (1/4) X by four times. Therefore, an optical signal having an intensity X is output from the expansion output port 200-b.

  As described above, in the optical switch system in which the two optical switches 2000 shown in FIG. 17 are combined, the minimum value of the optical signal output from the output port 300-b is (1/4) X. Further, the intensity of the optical signal output from the expansion output port 200-b is X. Therefore, if the two optical switches 2000 shown in FIG. 17 are considered as one set and an optical switch system is configured by connecting a plurality of these sets, the minimum value of the optical signal output from the output port 300 is (1/4). X. Therefore, the device that receives the optical signal from the optical switch 2000 can extract the information included in the optical signal regardless of the output port 300 from which the optical signal is received.

<Example 3>
Further, the optical switch 2000 of the third embodiment and the optical switch 2000 of the fourth embodiment may be connected. A connection method of the optical switch 2000 in this case will be described as a third embodiment.

  In the optical switch 2000 of the third embodiment, when the number of optical switches 2000 to be connected is large, the intensity of the optical signal output from each switching unit 2100 decreases. Therefore, for example, as shown in FIG. 18, the optical switch 2000 is connected by a method of “connecting three optical switches 2000 of the third embodiment and then connecting one optical switch 2000 of the fourth embodiment”. In FIG. 18, an optical switch 2000-a, an optical switch 2000-b, and an optical switch 2000-c are the optical switches 2000 according to the third embodiment. On the other hand, the optical switch 2000-d is the optical switch 2000 according to the fourth embodiment.

Here, the optical switch 2000 having the connection switch number acquisition unit 2050 is used as the optical switch 2000 of the third embodiment. However, in the present embodiment, the optical signal dividing unit 2020 divides the optical signal according to the following mathematical formula 2.

  Also, let X be the intensity of an optical signal input from the outside to the optical switch 2000-a. The optical signal dividing unit 2020 included in each optical switch 2000 divides the input optical signal into two equal parts, and outputs them to the optical signal input unit 2120 and the optical signal dividing unit 2020, respectively. Here, it is assumed that the optical signal amplification unit 2060 included in the optical switch 2000-d amplifies the intensity of the optical signal five times.

  Under such preconditions, when the optical switch 2000 is connected as shown in FIG. 18, the optical signals output from all the output ports are (1/5) X. The optical switch 2000-d outputs an optical signal to the optical signal dividing unit 2020 via the optical signal amplifying unit 2060. Therefore, the optical signal output from the optical switch 2000-d to another optical switch 2000 is an optical signal of intensity X obtained by amplifying the optical signal of intensity (1/5) X to five times the intensity. It is. Accordingly, if four optical switches 2000 connected as shown in FIG. 18 are considered as one set, and a plurality of such sets are connected, the intensity of the optical signals output from all the output ports is (1/5) X. It becomes.

<Example 4>
A usage example in which the optical switch 2000 is provided in a ROADM (Reconfigurable Optical Add Drop Multiplexer) device will be described as a fourth embodiment. In the fourth embodiment, the optical switch 2000 is used as a TPA (Transponder Aggregator).

  FIG. 19 shows a ROADM device 9000 of the fourth embodiment. The configuration of the ROADM device 9000 is a configuration of a general ROADM device. The ROADM device 9000 has four input paths 9010 to 9040 to which optical signals are input from the outside. Each optical signal input to the ROADM device 9000 is a wavelength-multiplexed optical signal. Here, it is assumed that each input optical signal is an optical signal obtained by combining optical signals having four wavelengths of λ1, λ2, λ3, and λ4.

  The ROADM device 9000 has four output paths 9510 to 9540 that output optical signals to the outside. The ROADM device 9000 outputs, from each output path, an optical signal having one wavelength among the four wavelengths λ1 to λ4 or an optical signal in which a plurality of wavelength signals are wavelength-multiplexed.

  The ROADM device 9000 includes an optical cross connect 9100, a drop TPA 9310, an add TPA 9320, and transponders 9410 to 9440. The number of input / output routes and the number of transponders of the ROADM device 9000 are four, respectively. However, the number of input / output paths and the number of transponders of the ROADM device 9000 may be other than four.

  The optical cross connect 9100 includes four 1: 4 optical splitters 9110 to 9140. The optical cross-connect 9200 includes four wavelength selective switches (WSS) 9210 to 9240.

  The 1: 4 optical splitter 9110 divides the optical signal input from the input route 9010 into four parts, outputs one optical signal to the TPA 9310, and outputs the remaining three optical signals to the wavelength selective switches 9220 to 9240. To do. Similarly, the other 1: 4 optical splitter also outputs one of the four divided optical signals to the TPA 9310 and outputs the remaining three to the wavelength selective switch. In addition, by providing a 1: 5 optical splitter instead of the 1: 4 optical splitter, a signal input to each input path may be output to the TPA 9310 and all the wavelength selective switches.

  Each of the drop TPA 9310 and the add TPA 9320 includes four optical switches 2000. FIG. 20 is a block diagram showing a unit switch 4000 used in the Drop TPA 9310. The unit switch 4000 is an optical switch in which the optical switch 2000 according to the second embodiment is specifically mounted. Here, the unit switch 4000 includes two 1: 2 optical splitters 4020 and two 2: 1 optical selectors 4040, respectively. The 1: 2 optical splitter 4020 is a specific implementation of the optical signal divider 2020. The 2: 1 optical selector 4040 is a specific implementation of the optical signal selection unit 2040. The unit switch 4000 includes a 2 × 2 switch 4100. The 2 × 2 switch 4100 is obtained by specifically mounting a switching unit 2100 having two optical signal input units 2120 and two optical signal output units 2140.

  Each 1: 2 optical splitter 4020 receives an optical signal from an optical splitter connected to the 1: 2 optical splitter 4020 among the optical splitters 9110 to 9140. Each 2: 1 optical selector 4040 outputs an optical signal to the input part (Rx) of the transponder connected to the 2: 1 optical selector 4040 among the transponders 9410 to 9440.

  FIG. 22 is a block diagram showing a unit switch 5000 used for the TPA 9320 for Add. The unit switch 5000 is an optical switch in which the optical switch 2000 according to the second embodiment is specifically mounted. Here, the unit switch 5000 includes two 1: 2 switches 5020 and two 2: 1 optical couplers 5040, respectively. The 1: 2 switch 5020 is a specific implementation of the optical signal divider 2020. The 2: 1 optical coupler 5040 is a specific implementation of the optical signal selection unit 2040. The unit switch 5000 includes a 2 × 2 switch 5100. The 2 × 2 switch 5100 is obtained by specifically mounting a switching unit 2100 having two optical signal input units 2120 and two optical signal output units 2140.

  An optical signal is input to each 1: 2 switch 5020 from an output unit (Tx) of a transponder connected to the 1: 2 switch 5020 among the transponders 9410 to 9440. Each 2: 1 optical coupler 5040 outputs an optical signal to the wavelength selective switch connected to the 2: 1 optical coupler 5040 among the wavelength selective switches 9210 to 9240.

  The drop TPA 9310 and the add TPA 9320 are configured by combining four optical switches 2000 described above in the same manner as shown in FIG. By doing so, the drop TPA 9310 and the add TPA 9320 each have 4 input ports and 4 output ports.

  The drop TPA 9310 receives an optical signal from the 1: 4 optical splitters 9110 to 9140 and outputs the optical signal to an arbitrary transponder 9410 to 9440. On the other hand, an add TPA 9320 receives optical signals from four transponders 9410 to 9440 and outputs the optical signals to arbitrary wavelength selective switches 9210 to 9240.

  Each of the transponders 9410 to 9440 includes a wavelength filter. Here, as described above, the optical signals input from the input paths 9010 to 9040 are optical signals obtained by wavelength-multiplexing optical signals having four wavelengths λ1 to λ4. The transponders 9410 to 9440 use a wavelength filter to extract an optical signal having a desired wavelength from the optical signal input from the Drop TPA 9310, and to perform an electrical operation such as a router or an OTN (Optical Transport Network) switch not shown. Output to the switch. This wavelength filter is preferably a tunable filter.

  Hereinafter, an example of the operation of the ROADM device 9000 will be shown. The drop TPA 9310 outputs the optical signal input from the input route 9010 to the transponder 9410. The transponder 9410 extracts only the optical signal having the wavelength λ1 from the optical signal and outputs it to the above-described electrical switch.

  The Drop TPA 9310 outputs the optical signal input from the input route 9020 to the transponder 9420. The transponder 9420 extracts only the optical signal having the wavelength λ2 from this optical signal and outputs it to the above-described electrical switch.

  Add TPA 9320 outputs both the optical signal with wavelength λ1 input from transponder 9410 and the optical signal with wavelength λ2 input from 9420 to wavelength selective switch 9230. As a result, an optical signal obtained by combining the optical signal having the wavelength λ1 and the optical signal having the wavelength λ2 is output from the output path 9510.

  In this way, the ROADM device 9000 has 1) which optical signal the Drop TPA 9310 outputs to which transponder, 2) what optical signal the transponder has to extract, and 3) the TPA 9320 for Add. However, which optical signal is output to which wavelength selective switch is appropriately set. As a result, the ROADM device 9000 can arbitrarily combine optical signals having different wavelengths included in a plurality of wavelength-multiplexed input optical signals and output the optical signals from any output path.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2013-041741 for which it applied on March 4, 2013, and takes in those the indications of all here.

Claims (8)

A plurality of optical signal input units to which optical signals are respectively input, and a plurality of optical signals which are input from one or more optical signal input units and output any one of the input optical signals Switching means comprising signal output means;
An optical signal is input from the outside of the optical switch, is connected to any one of the optical signal input means, and can be connected to any one of a plurality of optical signal dividing means included in another optical switch, A plurality of optical signal splitting means for splitting an optical signal input from the outside of the optical switch to a connected optical signal input means and an optical signal splitting means;
Have
Each optical signal dividing means is connected to the different optical signal input means, and is connected to different optical signal dividing means among the plurality of optical signal dividing means of other optical switches.
Light switch. An optical signal connected to any one of the optical signal output means, connectable to any one of optical signal selection means provided in another optical switch, and an optical signal input from the connected optical signal output means; A plurality of optical signal selection means for outputting any one of the optical signals input from the connected optical signal selection means;
Each optical signal selection unit is connected to a different optical signal output unit, and is connected to a different optical signal selection unit among the plurality of optical signal selection units included in other optical switches.
The optical switch according to claim 1.   The optical signal splitting unit determines the strength of an optical signal output to the optical signal splitting unit included in another optical switch according to the number of the optical signal splitting units through which the optical signal passes. Or the optical switch of 2.   4. The optical signal dividing means included in the optical switch is connected to optical signal dividing means included in another optical switch via an optical signal amplifying means that amplifies the optical signal. The optical switch as described in. An optical switch expansion method for connecting a first optical switch and a second optical switch,
Each optical switch is
A plurality of optical signal input units to which optical signals are respectively input, and a plurality of optical signals which are input from one or more optical signal input units and output any one of the input optical signals Switching means comprising signal output means;
An optical signal is input from the outside of the optical switch, is connected to any one of the optical signal input means, and can be connected to any one of a plurality of optical signal dividing means included in another optical switch, A plurality of optical signal dividing means for dividing an optical signal input from the outside of the optical switch and outputting it to the connected optical signal input means and optical signal dividing means,
Each optical signal dividing means is connected to different optical signal input means,
The optical switch expansion method is
An optical signal splitting means connecting step for connecting each of the optical signal splitting means included in the first optical switch to different optical signal splitting means among the plurality of optical signal splitting means included in the second optical switch; ,
Optical switch expansion method. The optical switch is
An optical signal connected to any one of the optical signal output means, connectable to any one of optical signal selection means provided in another optical switch, and an optical signal input from the connected optical signal output means; A plurality of optical signal selection means for outputting any one of the optical signals input from the connected optical signal selection means;
Each optical signal selection means is connected to different optical signal output means,
The optical switch expansion method is
An optical signal selection means connection step for connecting each of the plurality of optical signal selection means included in the first optical switch to a different optical signal selection means among the plurality of optical signal selection means included in the second optical switch. Having
The optical switch expansion method according to claim 5.   The optical signal dividing means included in the optical switch determines the strength of the optical signal output to the optical signal dividing means included in another optical switch according to the number of the optical signal dividing means that the optical signal passes through. The optical switch expansion method according to claim 5 or 6. In the optical signal dividing means connecting step, the optical signal dividing means included in the first optical switch is connected to the optical signal dividing means included in the second optical switch via an optical signal amplifying means that amplifies the optical signal. To
The optical switch expansion method according to claim 5.

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