WO2015198408A1 - Optical switch device and information processing device using same - Google Patents

Abstract

In the present invention, an optical transmission device has a plurality of optical transmitters, a plurality of optical receptors and a plurality of optical paths for connecting each of the optical transmitters and optical receptors. The optical paths are formed by large-scale optical switches equipped with a plurality of input and output ports; small-scale optical switches with a fewer number of ports than the number of ports on the large-scale switches are connected between the optical transmitters and the input ports of the large-scale optical switches; and small-scale optical switches with a fewer number of ports than the number of ports on the large-scale switches are connected between the output ports of the large-scale optical switches and the optical receptors. By using this optical transmission device, an information processing device that uses optical switches and that achieves both large scale and increased use efficiency due to high-speed switching is realized.

Description

Optical switch device and information processing device using the same

The present invention relates to an optical switch device and an information processing device used in an optical communication network or a server.

With the spread of mobile terminals and the rapid spread of cloud-based storage and computing, there is a need for not only communication networks but also large-capacity and high-speed networks in data centers. A data center is generally composed of a plurality of servers mounted on a rack, and the servers are connected to each other within the server rack or between server racks. Application of optical switches as well as electrical switches is being considered for connections between servers. The reason for introducing an optical switch is to increase the network capacity and increase the speed. However, since the optical switch can eliminate the conversion between electricity / light and light / electricity, which is required for the electrical switch, power saving is also expected. Has been. However, there are some problems for application of optical switches. For example, it is necessary to examine the configuration and control method of the optical switch, and there are still problems to be solved for full-scale practical use.

Non-Patent Document 1 shows an application example of an optical switch to a data center network and a study for improving efficiency. An optical switch using a MEMS (Micro Electro Mechanical System) mirror has a large number of ports, and a single unit can connect a plurality of servers. If a plurality of servers can be freely interconnected, the network configuration in the data center can be freely changed. The large number of ports of the MEMS type optical switch is attractive in that respect, and the MEMS type optical switch is one of optical switches expected to be applied to a data center network. However, the MEMS type optical switch has a problem, and the switch time is as slow as 10 to 100 milliseconds. When controlling an optical switch, a transmission delay corresponding to the overhead of software or a control plane occurs. Therefore, the delay required for path switching is said to be about 1 second. The delay required for this switching means that data transmission is impossible during that time, which causes deterioration in transmission efficiency of the network. Therefore, it is necessary to examine a method for shortening the switching time by devising a control method, and the present invention is also assumed to be used in this technical field.

JP 2003-199130 A

An optical switch capable of spatial optical path conversion using reflection by a MEMS mirror or deflection by a piezo can increase the number of switch ports. For example, Non-Patent Document 2 realizes a large-scale switch having 300 ports or more. ing. However, the switch speed depends on the operating speed of the mirror and is as slow as about milliseconds. On the other hand, when a refractive index change using the electric field effect is used in a waveguide type optical switch, high-speed switching is possible. For example, PLZT (Pb, La, Zr, Ti) and Si optical switches enable high-speed switching in nanoseconds. However, it is difficult to increase the scale of the waveguide type optical switch. When a large-scale optical switch is realized with a waveguide structure, it is common to realize a large scale by connecting 2 × 2 small-scale optical switches in multiple stages. The number of 2 × 2 small-scale optical switches used increases as the number of ports of the large-scale optical switch increases. That is, since the number of small-scale optical switches that propagate is increased, the propagation loss of light increases. FIG. 1 shows the correlation between the switching time of the optical switch and the number of ports. At present, large-scale optical switches that can be switched at high speed and have a large number of ports have not been realized.

Large scale is also required for optical switches used for optical connections between servers. If the number of ports of the optical switch is large, a plurality of devices (for example, servers) mounted inside and outside the rack can be connected to each other using one optical switch. In the case of a small scale, it is necessary to increase the number of optical switches, so that an installation space is required. Further, in order to freely connect a plurality of servers, it is necessary to connect small-scale optical switches in multiple stages. When the servers are connected by an optical switch, it is necessary to increase the switching speed of the optical switch in order to increase the efficiency of communication between the servers. Since the data transmission cannot be performed while the optical switch is switched, the data transmission unavailable time becomes long when the switching speed is low.

An object of the present invention is to provide an information processing apparatus using an optical switch device that achieves both high-efficiency by large-scale and high-speed switching.

In order to achieve the above object, the present invention adopts the structure described in the claims. The detailed structure of a large-scale and highly efficient optical switch device utilizing a small-scale high-speed switch optical switch and a large-scale low-speed switch optical switch will be described later. A typical invention of the present application will be described as follows. is there.

In a plurality of optical paths connecting a plurality of optical transmitters and a plurality of optical receivers mounted on a plurality of servers, etc., connected to a large-scale optical switch forming a plurality of paths and an input port of the large-scale optical switch Connected to an output port of a large-scale optical switch and a small-scale optical switch of k (k is an integer of 1 or more and n or less) × n (n is an integer of 2 or more) connecting the optical transmitter and the large-scale optical switch, It consists of an n × k small-scale optical switch that connects an optical receiver and a large-scale optical switch. Each of the small-scale optical switches is m (m is an integer of 1 or more), and the number of input / output ports of the large-scale optical switch is each nm or more. An optical signal from a certain optical transmitter is transmitted to a certain optical receiver through one optical path formed by a small-scale optical switch and a large-scale optical switch. Here, the large-scale optical switch means an optical switch having a large number of input and output ports, and the number of input / output ports (nm) is preferably 8 or more, for example. Further, a non-blocking optical switch in which switching between the ports does not interfere with each other is preferable. The small-scale optical switch means an optical switch having a small number of input and output ports. The number of input / output ports (k and n) is preferably less than 8, for example, and the number of input and output ports, that is, k and n. The number may be different. In the present invention, k is defined as 1 or more and n or less, and n is defined as 2 or more. In the following description, the small-scale optical switch is 1 × n or n × 1.

The main reasons that this configuration can achieve both high-speed switching and large scale are as follows. A case where optical signals are sequentially transmitted from one optical transmitter to different optical receivers will be briefly described. One output port of 1 × n small-scale optical switch connected to the optical transmitter, one input port of large-scale optical switch, one output port of large-scale optical switch, and n × 1 small-scale optical switch An optical path is formed by one input port, and the first optical signal is transmitted to a desired optical receiver. If the destination of the second optical signal (destination receiver) is different from the destination of the first optical signal, the path for the second optical signal using a different unused input / output port of the large-scale optical switch Is set in advance. After the transmission of the first optical signal is completed, the small-scale optical switch selects an input / output port that constitutes a route preset by the large-scale optical switch. At this time, the path switching time between the first and second optical signals depends on the switching speed of the small-scale optical switch, but the small-scale optical switch can be switched at a higher speed than the large-scale optical switch. Transmission by switching becomes possible. The number of optical transceivers that can be connected is determined by the number of ports of the large-scale optical switch. When the number of ports of the small-scale optical switch is n and the number is m, the number of input / output ports of the large-scale optical switch is required to be nm or more.

In the present invention, a small-scale optical switch capable of high-speed switching and a large-scale optical switch capable of large-scale switching are combined with each other, and a low-speed large-scale optical switch is used as a tool for configuring a plurality of paths. Among these routes, a high-speed small-scale optical switch is used as a tool for selecting a route to be used. Furthermore, by reserving the route in advance, the slow switching speed of the large-scale optical switch can be concealed, so the switching speed of the small-scale optical switch determines the transmission efficiency, and the transmission efficiency can be improved. A configuration in which a large-scale optical switch and a small-scale optical switch are combined as in the present invention may be applied to an optical path cross-connect device as described in Patent Document 1. The optical path cross-connect device is configured to connect a small-scale optical switch to a spare large-scale optical switch in preparation for failure of a large-scale optical switch. Although it is similar to the configuration of the present invention, in the present invention, the large-scale optical switch is not used as a backup route, but is used as a reserved route, so that the configuration and effects including the controller and control method are different. Will be specified in advance.

According to the present invention, it is possible to realize an information processing apparatus that uses an optical switch device that achieves both large-scale and high utilization efficiency by high-speed switching.

The figure which shows the correlation of the number of ports of an optical switch, and switching speed. The figure which shows the optical switch structure of this invention. The figure which shows the path | route of data transmission. The figure which shows the reservation path | route at the time of data transmission. The figure which shows repetition of route switching and reservation. FIG. 4 is a schematic diagram of data transmission and route reservation / switching from the same transmitter, and shows a conventional large-scale optical switch. FIG. 3 is a schematic diagram of data transmission from the same transmitter and path reservation / switching, and shows the optical switch of the present invention. FIG. 4 is a schematic diagram of data transmission from the same transmitter and path reservation / switching, and shows an optical switch of the present invention (data transmission time> reservation + large-scale optical switch path switching time). The figure which shows the optical switch structure and route reservation at the time of n = 3. The figure which shows the optical switch structure at the time of l> m. The figure which shows the management by a controller. The figure which shows the image mounted in the server rack inside and outside.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted. Also, in the following embodiments, the description of the same or similar parts will not be repeated in principle unless particularly necessary.

FIG. 2 shows the configuration of the optical switch presented in the present invention. The input port of one nm × nm large-scale optical switch 10 is connected to m 1 × n small-scale optical switches 20, and the output port of the large-scale optical switch 10 is m n × 1 small-scale switches. 21 is connected. Furthermore, each small-scale optical switch 20, 21 is connected to a transmitter 30 and a receiver 31, respectively. In FIG. 2, n = 2. 10 is nm × nm large-scale optical switch, 20 is k × n small-scale optical switch (k = 1, n = 2), 21 is n × k small-scale optical switch (k = 1, n = 2), 30 is An optical transmitter 31 is an optical receiver.

The role of each switch during data transmission will be described with reference to FIG. 11 is a path connecting the 1 × 2 small-scale optical switch and the large-scale optical switch, 12 is a path connecting the large-scale optical switch and the 2 × 1 small-scale optical switch, and 41 is a transmission path of the optical signal. When transmitting data to the receiver 31 ₁ from the transmitter 30 _1, the optical signal from the optical transmitter 30 ₁ is connected to the 1 × 2 small optical switch 20 _1. Although the optical switch 20 ₁ can select either of the route _{11 11} or path _{11 12,} wherein the selecting the path _{11 11.} The large-scale optical switch 10 by leaving to establish a path between the paths _{11 11} and the path _{12 11,} the optical signal from the path _{11 11} is transmitted to the path _{12 11.} In the 2 × 1 small-scale optical switch 21 ₁ , the route 12 ₁₁ or the route 12 ₁₂ can be selected. Here, the route 12 ₁₁ is selected. Therefore, the signal from the path 12 ₁₁ is transmitted to the optical receiver 31 ₁ through the 2 × 1 small-scale optical switch 21 ₁ . The large-scale optical switch 10 establishes a path for connecting the optical transceivers 30 and 31, and the small-scale optical switches 20 and 21 play a role of selecting a path established in the large-scale switch 10.

Here, it can be seen that the 1 × 2 small-scale optical switch 20 ₁ , the 2 × 1 small-scale optical switch 21 _1, and the large-scale optical switch 10 have unused paths. 1 × 2 is a path _{12 12} of the small optical switch 20 ₁ of the route _{11 12} and 2 × 1 small optical switch 21 _1. In other small-scale optical switches, there is only one path through which an optical signal can be transmitted, so there is always one unused path. By securing the next route in advance using this unused route, the transmission delay due to the switching time of the large-scale optical switch 10 is reduced.

FIG. 4 shows an optical switch configuration at the time of route reservation. Reference numeral 42 denotes a reserved route. If the optical transmitter 30 ₁ transmits data to the optical receiver 31 _m after transmitting the data to the optical receiver 31 _1, 1 × 2 unused paths of the optical switch 20 ₁ at the time of data transmission to the optical receiver 31 ₁ 11 ₁₂ and the unused path of 2 × 1 optical switch 21 _m , for example, 12 _m2 are used to reserve path 42 of large-scale optical switch 10. Completed data transmission to the optical receiver 31 _1, if the destination of the optical transmitter 30 ₁ is changed to the optical receiver 31 _m, 1 × 2 small optical switches 20 ₁ and 2 × 1 Small light by switching the path of the switch 21 _m to the path _{11 12} and the path _{12 m @ 2} respectively, transmission path to the optical receiver 31 _m can be established, allowing data transmission. At this time, since the optical signal is not transmitted to the path 11 ₁₁ and the path 12 ₁₁ , an unused path can be formed again. FIG. 5 shows repetition of route switching and reservation. As shown in FIG. 5, the unused route is used for route reservation corresponding to the next destination. For example, in FIG. 5, a route to the optical receiver 31 _m-1 is reserved. Since the route reservation is executed simultaneously with the data transmission, it is possible to save time in comparison with the conventional procedure for executing the route reservation / switching after the data transmission.

FIG. 6 shows a schematic diagram of data transmission and route reservation / switching from the same transmitter, that is, a relationship in time axis of data transmission, reservation, and route switching. FIG. 6A shows a conventional case in which only the large-scale optical switch 10 is used. Reservation and path switching to destination 2 are executed after data transmission to destination 1, and data is transmitted to destination 2 after the path is established. Thereafter, the procedure for establishing the next route after data transmission is always repeated. Here, the reservation means that the right to use the path is obtained by confirming whether or not data transmission to the destination is possible, and the path switching means that the optical path of the large-scale optical switch 10 is switched. In the conventional example, data transmission cannot be performed at the time of reservation and path switching. Therefore, if these two processes take time, an optical switch system with poor transmission efficiency is obtained. Actually, a large-scale optical switch 10 such as a MEMS switch has a path switching time on the order of milliseconds. FIG. 6B shows a time series in the optical switch of the present invention. During data transmission to destination 1, reservation to destination 2 and path switching of the large-scale optical switch are executed simultaneously. After both processes are completed, the paths of the small-scale optical switches 20 and 21 are switched, and data is transmitted to the destination 2. At the same time as the start of data transmission to destination 2, reservation and path switching of destination 3 are executed, and data transmission and path reservation are always executed simultaneously. This is a concealment of transmission unavailable time in the conventional example. As shown in FIG. 6B, if the data transmission time 51 is longer than the sum of the times of the reservation 52 and the large-scale optical switch path switching 53, the data transmission unavailable time is defined by the switching time 54 of the small-scale optical switch. If a small-scale optical switch is configured with a waveguide-type high-speed switching optical switch (LiNbO ₃ , PLZT, compound semiconductor, Si, etc.), high-speed switching in the nanosecond order is possible, so the data transmission unavailable time is short, The optical switch system has good transmission efficiency. FIG. 6C shows the case of the optical switch of the present invention (data transmission time <reservation + large-scale optical switch path switching time). 51 is a data transmission time, 52 is a reservation, 53 is a large-scale optical switch path switch, and 54 is a small-scale optical switch path switch. As shown in FIG. 6C, the data transmission time 51 may be shorter than the total time of the reservation 52 and the large-scale optical switch path switching 53. The data transmission unavailable time at this time is a time obtained by adding the small-scale optical switch path switching time 54 to the time obtained by subtracting the data transmission time from the total time of the reservation 52 and the large-scale optical switch path switching 53. If the small-scale optical switch path switching time 54 is short, even in this case, the data transmission disabled time can be made shorter than in the conventional case (FIG. 6A). In order to obtain the effect of the present invention, it is ideal to make the small-scale optical switch path switching time 54 as short as possible, but it is necessary to make it at least shorter than the large-scale optical switch path switching time 53.

The path switching timing of the small optical switches 20 and 21 is when the path reservation is completed and the previous data transmission is completed, and it is desirable to switch the two small optical switches 20 and 21 simultaneously. The reservation of the route using the large-scale optical switch 10 means that the optical path switching of the optical switch is advanced in advance and the route is established, and if it is a spatial non-blocking optical switch such as a MEMS switch, all routes Can be set without interfering with each other. Even if the large-scale optical switch 10 has reserved a route in advance, the route between the 1 × 2 small-scale optical switch 20 and the 2 × 1 small-scale optical switch 21 has not been established. The light is blocked and leakage is suppressed.

3-5 shows an example in which the number of ports (n) of the small-scale optical switches 20 and 21 is 2, but 3 or 4 may be used if n is 2 or more. In FIG. 7, reference numeral 43 denotes a reserved route. FIG. 7 shows an example of an optical switch configuration and route reservation when n = 3. As n is larger, the number of routes that can be reserved can be increased, and a plurality of reserved routes can be established simultaneously. Data transmission unavailable time can be further shortened. For example, as shown in FIG. 6C, even when the data transmission time 51 is shorter than the sum of the reservation 52 and the large-scale optical switch route switching time 54, the route reservation for the destinations 2 and 3 can be started almost simultaneously. For example, the data transmission unavailable time from the destination 1 to the destination 2 is equivalent to that in FIG. 6C, but the data transmission unavailable time from the destination 2 to the destination 3 can be equivalent to that in FIG. 6B. However, as n is increased, the optical loss in the small-scale optical switches 20 and 21 increases, and the number of ports of the large-scale optical switch 10 required when the required number of optical transceivers does not change. In view of the increase of n, n has an upper limit, and 1 <n ≦ 10 is considered to be a realistic value. On the other hand, the number of ports nm of the large-scale optical switch 10 is determined by the number of small-scale optical switches 20 and 21 to be connected (m) and the number of ports of the small-scale optical switches 20 and 21 (n).

The number of ports of the large-scale optical switch 10 is nm, but it may be greater than or equal to nm in consideration of additionally installing the optical transceivers 30 and 31. The optical transmission apparatus in which the optical switch of the present invention is introduced is assumed to be used in a data center or an HPC (High Performance Computer), and needs to be scalable to support the addition of the transceivers 30 and 31. FIG. 8 shows an optical switch configuration when l> m. As shown in FIG. 8, by setting the number of ports of the large-scale optical switch 10 to nl (l> m), even when m optical transceivers 30 and 31 are initially connected, (lm) The number of optical transceivers 30 and 31 can be increased.

The large-scale optical switch 10 is characterized by a large number of ports, and the small-scale optical switches 20 and 21 are characterized by a high switching speed. The large-scale optical switch 10 is preferably constituted by a spatial optical switch such as MEMS, and the small-scale optical switches 20 and 21 are preferably constituted by waveguide-type optical switches. However, if the number of ports of the large-scale optical switch 10 is not so large, for example, up to about 64 ports, a waveguide type optical switch using a quartz PLC (Planar Lightwave Circuit) is used as the large-scale optical switch 10. There is no problem. It goes without saying that the effects of the present invention can be obtained if an optical switch characterized by being large-scale and capable of high-speed switching is used in addition to the above combinations. In addition, a place where the small-scale optical switches 20 and 21 are mounted is also mentioned. The small-scale optical switches 20 and 21 may be inserted between the optical transceivers 30 and 31 and the large-scale optical switch 10. For example, when it is installed on the optical transceiver 30 or 31 side, when it is installed on the large-scale optical switch 10 side, or when it is installed as a single device without being incorporated in either of them, there is any mounting place. Think.

It is preferable that the large-scale optical switch 10 and the small-scale optical switches 20 and 21 are collectively managed by the controller 60. FIG. 9 shows management by the controller. FIG. 9 specifically shows a configuration in which the controller 60 is mounted. Reference numeral 61 denotes a SW control signal line, and 62 denotes a communication line between the transceiver and the controller. The controller 60 is connected by a signal line 61 for controlling the large-scale optical switch 10 and the small-scale optical switches 20 and 21. A route reservation (including switching) of the large-scale optical switch 10 and a route switch of the small-scale optical switches 20 and 21 are instructed. By grasping the usage status of the large-scale optical switch 10 and the small-scale optical switches 20 and 21 collectively by the controller 60, it is possible to avoid a collision in the route reservation to the next destination. Since the controller 60 needs to communicate with the optical transceivers 30 and 31, the controller 60 is connected by a communication line 62. Transmission information such as destination and data amount is transmitted from the optical transmitter 30 to the controller 60. The controller executes path reservation and path switching of the large-scale optical switch 10 based on the information. After confirming that the previous data transmission has been completed and that the path switching of the large-scale optical switch 10 has been completed, the controller gives the optical transmitter 30 permission for the next data transmission. At the same time, the small-scale optical switches 20 and 21 are instructed to switch routes. On the other hand, it is preferable that the optical receivers 31 be connected to each other so that they can be known to the controller when a failure or the like occurs such as when a transmission signal error occurs.

The optical transmission apparatus of the present invention can be functioned as a part of an information processing apparatus by being mounted inside or outside a server rack, for example. FIG. 10 shows a mounting image inside and outside the server rack. FIG. 10 shows a specific example mounted on the server rack 70. A plurality of servers 71 are mounted in the server rack 70. Reference numeral 72 denotes a Top of Rack SW (optical switch or electrical switch), 73 denotes an aggregation SW (optical switch or electrical switch), and 74 denotes an optical fiber. On the upper stage of the server rack 70, a ToR (Top of rack) switch 72 that enables connection between the servers 71 and the inside and outside of the rack is mounted. Although the current ToR switch 72 is composed of an electrical switch, the optical switch of the present invention can be applied to connect a plurality of servers 71. In that case, the optical fiber 74 is used for wiring between the server 71 and the ToR switch 72. An aggregation switch 73 generally exists as a switch for connecting the racks, and an electrical switch or a low-speed switching optical switch is used. It is possible to apply the optical switch of the present invention to such an aggregation switch 73 as well. In addition, although storage etc. are also mounted in the server rack 70, only the server 71 was described here in order to simplify description.

The following effects are obtained by the optical switch unit using a large-scale optical switch that forms multiple paths and a plurality of small-scale optical switches connected to the input / output ports of the large-scale optical switch, and the control system that controls each optical switch It is done.
1) A small-scale optical switch capable of high-speed switching and a large-scale optical switch capable of high-speed switching but having a low switching speed are combined with each other. By using a high-speed and small-scale optical switch as a tool for selecting a path to be used, a large-scale and high-speed switchable optical switch can be configured.
2) By using each port of the large-scale optical switch connected to the unused path of the small-scale optical switch, the next path is secured in advance, thereby transmitting due to the switching time of the large-scale optical switch having a slow switching speed. Delay can be reduced. By performing path switching of the large-scale optical switch in advance, the switching time of the large-scale optical switch is concealed, and transmission with high utilization efficiency is possible with a short data transmission unavailable time.
3) By providing more ports for the large-scale optical switch than the product of the number of small-scale optical switches and the number of ports, the scalability is such that the same switch can be applied even when additional transceivers are added. is doing.

DESCRIPTION OF SYMBOLS 10 ... nm * nm large-scale optical switch, 11 ... path | route which connects 1 * 2 small scale optical switch and large scale optical switch, 12 ... path | route which connects large scale optical switch and 2 * 1 small scale optical switch, 20 ... k * n Small optical switch (k = 1, n = 2), 21 ... n × k Small optical switch (k = 1, n = 2), 30 ... Optical transmitter, 31 ... Optical receiver, 41 ... Optical signal 42 ... Reserved route, 43 ... Reserved route, 51 ... Data transmission time, 52 ... Reserved, 53 ... Large-scale optical switch route switching, 54 ... Small-scale optical switch route switching, 60 ... Controller, 61 ... SW control Signal line 62 ... Communication line between transceiver and controller, 70 ... Server rack, 71 ... Server, 72 ... Top of Rack SW (optical switch or electrical switch), 73 ... Aggregation SW (optical switch) 74 or optical fiber.

Claims (14)

1. A plurality of optical transmitters, a plurality of optical receivers, and a plurality of optical paths connecting them, each of which is formed by a large-scale optical switch having a plurality of input and output ports; A small-scale optical switch having a smaller number of ports than the large-scale optical switch is connected between the optical transmitter and an input port of the large-scale optical switch, and the number of ports is larger than the number of ports of the large-scale optical switch. An optical transmission device characterized in that a small-scale optical switch with a small number of switches is connected between an output port of the large-scale optical switch and the optical receiver.
2. The number of ports of the small-scale optical switch connected between the optical transmitter and the input port of the large-scale optical switch is k (k is an integer of 1 to n) × n (n is an integer of 2 or more). The number of ports of the small-scale optical switch connected between the output port of the large-scale optical switch and the optical receiver is n × k, and each of the small-scale optical switches is m (m is 1 or more). The optical transmission apparatus according to claim 1, wherein the number of ports of the large-scale optical switch is not less than nm.
3. The optical transmission apparatus according to claim 1, wherein the optical transmitter, the small-scale optical switch, and the large-scale optical switch are collectively managed by a controller.
4. The optical transmission device according to claim 1, wherein the switching time of the small-scale optical switch is shorter than the switching time of the large-scale optical switch.
5. 2. The optical transmission apparatus according to claim 1, wherein the small-scale optical switch is constituted by a waveguide type or a spatial type optical switch, and the large-scale optical switch is constituted by a spatial type optical switch.
6. A plurality of optical transmitters, a plurality of optical receivers, and a plurality of optical paths connecting them, each of which is formed by a large-scale optical switch having a plurality of input and output ports, A small-scale optical switch of k (k is an integer from 1 to n) × n (n is an integer of 2 or more) connected to the input port of the large-scale optical switch and connecting the optical transmitter and the large-scale optical switch; The n × k small-scale optical switch connected to the output port of the large-scale optical switch and connecting the optical receiver and the large-scale optical switch, and one k × n and n × k The small-scale optical switch selects a port by selecting each port of the large-scale optical switch connected to the small-scale optical switch, and each port of the large-scale optical switch has one path among a plurality of optical paths. The light path is determined by selecting Transmission equipment.
7. In each port of the large-scale optical switch connected to one k × n and n × k small-scale optical switch, an optical signal is transmitted to only one port and simultaneously to n−1 unused ports. The optical transmission apparatus according to claim 6, wherein no optical signal is transmitted.
8. 8. The n-1 unused port reserves a route for connecting a next transmission destination different from a transmission destination of a signal transmitted from the optical transmitter in advance. Optical transmission equipment.
9. Of the m small-scale optical switches (m is an integer of 1 or more), the controller controls the switching from the port through which the optical signal is transmitted to the port through which the optical signal is not transmitted. The optical transmission device according to claim 6.
10. A plurality of optical transmitters, a plurality of optical receivers, and a plurality of optical paths connecting them, each of which is formed by a large-scale optical switch having a plurality of input and output ports; A small-scale optical switch having a smaller number of ports than the large-scale optical switch is connected between the optical transmitter and an input port of the large-scale optical switch, and the number of ports is larger than the number of ports of the large-scale optical switch. An optical transmission device connected between an output port of the large-scale optical switch and the optical receiver is installed in a server rack or outside the server rack. Processing equipment.
11. The number of ports of the small-scale optical switch connected between the optical transmitter and the input port of the large-scale optical switch is k (k is an integer of 1 to n) × n (n is an integer of 2 or more). The number of ports of the small-scale optical switch connected between the output port of the large-scale optical switch and the optical receiver is n × k, and each of the small-scale optical switches is m (m is 1 or more). The information processing apparatus according to claim 10, wherein the number of ports of the large-scale optical switch is greater than or equal to nm.
12. 11. The information processing apparatus according to claim 10, wherein the optical transmitter, the small-scale optical switch, and the large-scale optical switch are collectively managed by a controller.
13. 11. The information processing apparatus according to claim 10, wherein a switching time of the small-scale optical switch is shorter than a switching time of the large-scale optical switch.
14. 11. The information processing apparatus according to claim 10, wherein the small-scale optical switch is configured by a waveguide type or a spatial type optical switch, and the large-scale optical switch is configured by a spatial type optical switch.

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