Signal processing device

Abstract

A plurality of photoelectric conversion circuits (30A–30H) of a signal processing device (10) include active photoelectric conversion circuits (30A–30F) that are connected to input / output ports (41A–41F) of an optical switch (40), and standby photoelectric conversion circuits (30G and 30H) that are connected to input / output ports (41G and 41H) of an optical switch (20). When, for example, the photoelectric conversion circuit (30A) among the photoelectric conversion circuits (30A–30F) fails, the optical switch (40) connects an input port (42A), which is connected to the input / output port (41A), and the input / output ports (41G and 41H), to which the standby photoelectric conversion circuits (30G and 30H) are connected.

Description

Signal processing device

[0001] The present invention relates to a signal processing device such as a network switch.

[0002] Conventionally, a signal processing device that converts an optical signal into an electrical signal and processes the converted electrical signal has been known. Such a signal processing device includes a plurality of optoelectronic conversion circuits that convert an optical signal into an electrical signal, and a processor that processes the electrical signal converted by any one of the plurality of optoelectronic conversion circuits. The optoelectronic conversion circuit is configured as a CPO (Co-packaged Optical) type module (Non-Patent Document 1). In addition to or instead of converting the optical signal into an electrical signal, the plurality of optoelectronic conversion circuits may be configured to perform electro-optical conversion that converts an electrical signal from a processor into an optical signal by modulating light as a carrier from a light source.

[0003] ”Implementation Agreement for a 3.2Tb / s Co-Packaged (CPO) Module”, [online], March 29, 2023, OIF, [September 10, 2024 search], Internet <URL:https: / / www.oiforum.com / wp-content / uploads / OIF-Co-Packaging-3.2T-Module-01.0.pdf>

[0004] In a conventional signal processing device, it is conceivable that any one of the plurality of optoelectronic conversion circuits or the light source fails, but no countermeasures against such a failure have been taken.

[0005] An object of the present invention is to ensure the redundancy of an optoelectronic conversion circuit or a light source.

[0006] A signal processing device according to a first aspect of the present invention includes an optical switch having a plurality of input ports and a plurality of output ports, which outputs a first optical signal input to any of the plurality of input ports from any of the plurality of output ports; a plurality of photoelectric conversion circuits connected to each of the plurality of output ports, which convert the first optical signal from the connected output port among the plurality of output ports into a first electrical signal; and a processor which processes the first electrical signal converted by any of the plurality of photoelectric conversion circuits, wherein the plurality of photoelectric conversion circuits include a first active photoelectric conversion circuit connected to a first output port among the plurality of output ports, and a second backup photoelectric conversion circuit connected to a second output port among the plurality of output ports, and the optical switch connects a first input port connected to the first output port among the plurality of input ports to a second output port when the first photoelectric conversion circuit fails.

[0007] According to the above configuration, redundancy of the photoelectric conversion circuit is ensured.

[0008] A signal processing device according to a second aspect of the present invention includes: a processor that processes a first electrical signal and outputs a second electrical signal indicating the processing result; a first light source of an active system that emits a first light; a second light source of a backup system that emits a second light; an electro-optical conversion circuit that converts the second electrical signal into an optical signal by modulating the first light from the first light source based on the second electrical signal from the processor; and an optical switch that connects the electro-optical conversion circuit and the second light source when the first light source fails, thereby inputting the second light as the first light to the electro-optical conversion circuit.

[0009] According to the above configuration, redundancy of the light source is ensured.

[0010] Figure 1 is a diagram showing an overview of the configuration of a signal processing device according to the first embodiment of the present invention. Figure 2 shows an overview of the configuration of a photoelectric conversion circuit according to the first embodiment of the present invention. Figure 3 is a diagram showing an overview of the configuration of another example of a signal processing device according to the first embodiment of the present invention. Figure 4 is a diagram showing an overview of the configuration of a signal processing device according to the second embodiment of the present invention. Figure 5 is a diagram showing an overview of the configuration of another example of a signal processing device according to the second embodiment of the present invention. Figure 6 is a diagram showing an overview of the configuration of a photoelectric conversion circuit according to the second embodiment of the present invention.

[0011] The signal processing apparatus according to this embodiment will be described below with reference to the drawings. In the following description, elements having the same or similar functions will be denoted by the same reference numerals.

[0012] (First Embodiment) The signal processing device 10 shown in Figure 1 is configured as a network switch that transfers data to an optical network installed in a data center and performing distributed processing (for example, synchronous parallel computing by GPUs (Graphics Processing Units) in AI learning and big data processing). The signal processing device 10 is configured to transfer packets transmitted from a user terminal in the form of optical signals to predetermined computing devices (such as GPUs) that constitute the optical network.

[0013] The signal processing device 10 comprises a processor 20, photoelectric conversion circuits 30A to 30H, an optical switch 40, and a controller 50. The electrical connections described below are made by one or more (for example, four) electrical signal lines. The optical connections described below are made by one or more (for example, four) optical signal lines (such as optical fibers).

[0014] The processor 20 consists of a single chip comprising an ASIC (Application Specific Integrated Circuit), FPGA (Field-Programmable Gate Array), DSP (Digital Signal Processing), and CPU (Central Processing Unit). In this context, the processor 20 functions as a network switch that processes packet forwarding. The processor 20 has eight input / output ports 21A to 21H.

[0015] The input / output ports 21A to 21H are electrically connected to the photoelectric conversion circuits 30A to 30H, respectively. The photoelectric conversion circuits 30B to 30H are optically connected to the input / output ports 41B to 41H of the optical switch 40, respectively. The input / output ports 42A to 42F of the optical switch 40 are connected to a user terminal or a computing device that constitutes the optical network described above.

[0016] The optical switch 40 includes optical couplers 43A to 43F. Optical couplers 43A to 43F have a 2:1 input / output configuration. Two inputs / outputs on one end of optical coupler 43A are optically connected to input / output port 41A and connection terminal 44A, respectively. One input / output on the other end of optical coupler 43A is optically connected to input / output port 42A. Similarly, one of the two inputs / outputs on one end of optical couplers 43B to 43F is optically connected to input / output ports 42B to 42F, respectively, and the other is optically connected to connection terminals 44B to 44F, respectively. One input / output on the other end of optical couplers 43B to 43F is optically connected to input / output ports 42B to 42F, respectively. Optical couplers 43A to 43F are also referred to as optical power couplers (the same applies to optical couplers in this specification).

[0017] The optical switch 40 can switch the connection relationship between input / output ports 41A to 41H and input / output ports 42A to 42F by connecting any of the connection terminals 44A to 44F to any of the input / output ports 41G to 41H. More specifically, the optical switch 40 is configured as an optical path switch that switches at least a portion of the optical path between input / output ports 41A to 41H and input / output ports 42A to 42F. Initially, two of the connection terminals 44A to 44F may be connected to input / output ports 41G to 41H, respectively.

[0018] The optical switch 40 outputs an optical signal indicating a packet input from an optical network or user terminal to one of the input / output ports 42A to 42F from one of the input / output ports 41A to 41H. Specifically, the optical signal is output from one of the input / output ports 41A to 41H connected to the input / output port from which the optical signal was input. For example, if an optical signal is input to input / output port 42A, this optical signal is output from input / output port 41A, which is optically connected to input / output port 42A via optical coupler 43A. However, if the connection terminal 44A, which is optically connected via optical coupler 43A, is not connected to either input / output port 41G or 41H, the optical signal input to input / output port 42A will not be output from either input / output port 41G or 41H. In other words, this optical signal is output only from input / output port 41A. If the connection terminal 44A is connected to either the input / output port 41G or 41H, the optical signal input to the input / output port 42A will be output not only from the input / output port 41A but also from the input / output port 41G or 41H connected to this connection terminal 44A.

[0019] The photoelectric conversion circuits 30A to 30H convert the optical signal from the optical switch 40 into an electrical signal and output the converted electrical signal to the processor 20. Furthermore, the photoelectric conversion circuits 30A to 30H also function as an electro-optical conversion circuit, converting the electrical signal from the processor 20 (described later) into an optical signal and outputting the converted optical signal to the optical switch 40.

[0020] The photoelectric conversion circuits 30A to 30H have similar configurations. Below, examples of the configurations of the photoelectric conversion circuits 30A to 30H will be described using photoelectric conversion circuit 30A as an example. As shown in Figure 2, the photoelectric conversion circuit 30A includes a photoelectric conversion element 31, a converter 32, a control circuit 33, a driver circuit 34, and a modulator 35.

[0021] The photoelectric conversion element 31 includes, for example, a photodiode, and converts the optical signal from the input / output port 41A of the optical switch 40 into an electrical signal. The converter 32 includes, for example, a transimpedance amplifier, and converts the electrical signal converted by the photoelectric conversion element 31 into a voltage signal. The control circuit 33 includes, for example, a DSP (Digital Signal Processor), and outputs the voltage signal converted by the converter 32 to the processor 20 (input / output port 21A). With this configuration, the photoelectric conversion circuit 30A converts the optical signal from the optical switch 40 into an electrical signal.

[0022] The control circuit 33 inputs an electrical signal from the processor 20 (input / output port 21A) to the driver circuit 34. This electrical signal represents the processing result of the electrical signal that has been input to and processed by the processor 20. The driver circuit 34 controls the modulator 35 based on the input electrical signal. The modulator 35 includes, for example, a Mach-Zehnder modulator and modulates the reference light (the light that becomes the carrier wave in the optical signal) from the light source L under the control of the driver circuit 34. The modulated reference light is an optical signal converted from the electrical signal from the processor 20 and is input to the optical switch 40 (input / output port 41A). The light source L is, for example, a laser diode.

[0023] Similar to the photoelectric conversion circuit 30A, the photoelectric conversion circuits 30B to 30H in Figure 1 also include a photoelectric conversion element 31, a converter 32, a control circuit 33, a driver circuit 34, and a modulator 35.

[0024] Each of the photoelectric conversion circuits 30A to 30F in Figure 1 operates as the primary system. Photoelectric conversion circuits 30G and 30H are provided as backup systems to operate in the event of a failure in any of the primary system's photoelectric conversion circuits 30A to 30F.

[0025] The controller 50 consists of at least one or a combination of several computing devices, such as a computer, ASIC, FPGA, or DSP. The controller 50 controls the processor 20, the photoelectric conversion circuits 30A to 30H, and the optical switch 40. Under normal conditions (when there are no faulty photoelectric conversion circuits), the controller 50 turns on the power to the active photoelectric conversion circuits 30A to 30F and turns off the power to the backup photoelectric conversion circuits 30G to 30H. The controller 50 controls the optical switch 40 and controls the connection relationship between input / output ports 41A to 41H and input / output ports 42A to 42F.

[0026] Here, we will explain the operation of the signal processing device 10 under normal conditions. Packets from an external optical network are input as optical signals to input / output ports 42A to 42F. Here, we assume that a packet as an optical signal is input to input / output port 42A. This packet is distributed to input / output port 41A and connection terminal 44A by the optical coupler 43A. Under normal conditions, connection terminal 44A is not connected to input / output ports 41G to 41H. Therefore, packets are output only from input / output port 41A. Note that, in its initial state, connection terminal 44A may be connected to, for example, input / output port 41G. In this case, packets are output from input / output port 41G to the photoelectric conversion circuit 30G, but since the power to the photoelectric conversion circuit 30G is off, these packets are not input to the processor 20.

[0027] Packets output from input / output port 41A are input to photoelectric conversion circuit 30A and converted into electrical signals by photoelectric conversion circuit 30A. Packets converted into electrical signals are input to input / output port 21A of processor 20. Process the input packets. For example, as part of packet processing, processor 20 analyzes the packet header. As part of packet processing, processor 20 may rewrite a part of the packet. As part of packet processing, processor 20 refers to an address table that shows the correspondence between MAC addresses and input / output port numbers, which is stored in the processor itself or in a memory unit not shown, and obtains the input / output port number corresponding to the MAC address contained in the packet header. Processor 20 outputs the packet from the input / output port with the port number obtained above, from among input / output ports 21A to 21H. Here, it is assumed that the packet is output from input / output port 21C. The packet output from input / output port 21C is an electrical signal that represents the packet as a result of processing. The resulting packet may contain the same data as the original packet, or it may contain data with some parts of the original packet (for example, part of the header) modified.

[0028] Packets output from input / output port 21C are input to photoelectric conversion circuit 30C. The photoelectric conversion circuit 30C converts the input packets from electrical signals to optical signals, and inputs the converted optical signals to input / output port 41C of the optical switch 40. Packets input to input / output port 41C are output to the optical network from input / output port 42C, which is connected to input / output port 41C via optical coupler 43C.

[0029] Through the processes described above, packet forwarding (switching) is achieved.

[0030] The controller 50 monitors the photoelectric conversion circuits 30A to 30F in parallel with packet forwarding processing. For example, each of the photoelectric conversion circuits 30A to 30F periodically outputs a predetermined electrical signal, which is a life signal, from the DSP 33. The photoelectric conversion circuits 30A to 30F cannot output a life signal when they fail. The controller 50 monitors for the presence or absence of this life signal to check for failures in each of the photoelectric conversion circuits 30A to 30F. When the controller 50 does not receive a life signal for a certain period of time, it generates and stores failure information that identifies the photoelectric conversion circuit that is the source of this life signal among the photoelectric conversion circuits 30A to 30F as the failed photoelectric conversion circuit. The failure information includes, for example, the type, location, and / or ID of the failed photoelectric conversion circuit. The generation of this failure information allows for the detection of a failure in a photoelectric conversion circuit.

[0031] Based on the fault information, the controller 50 identifies the faulty photoelectric conversion circuit among the photoelectric conversion circuits 30A to 30F. Here, let's assume that photoelectric conversion circuit 30A has failed. The controller 50 activates either the backup photoelectric conversion circuit 30G or 30H in place of the faulty active photoelectric conversion circuit 30A. Here, let's assume that the backup photoelectric conversion circuit 30G is activated. The details of these actions are explained below.

[0032] When the controller 50 detects a failure in the photoelectric conversion circuit 30A, it turns off the power to the failed photoelectric conversion circuit 30A. The photoelectric conversion circuit 30A may also turn off its own power through its own function. Furthermore, the controller 50 turns on the power to the photoelectric conversion circuit 30G and starts up the photoelectric conversion circuit 30G. The controller 50 also controls the optical switch 40 to optically connect the connection terminal 44A, which is connected to the optical coupler 43A that is connected to the failed photoelectric conversion circuit 30A via the input / output port 41A, to the input / output port 41G to which the backup photoelectric conversion circuit 30G is connected (see dotted line in Figure 1).

[0033] Packets, which are optical signals input to input / output port 42A, are distributed by the optical coupler 43A to input / output port 41A and input / output port 41G connected to connection terminal 44A. As described above, the photoelectric conversion circuit 30A connected to input / output port 41A is powered off, and the photoelectric conversion circuit 30G connected to input / output port 41G is powered on. Therefore, packets are input to the processor 20 via photoelectric conversion circuit 30G, not via photoelectric conversion circuit 30A. This allows the backup photoelectric conversion circuit 30G to operate in place of the faulty photoelectric conversion circuit 30A.

[0034] When the controller 50 connects the connection terminal 44A to the input / output port 41G and powers on the photoelectric conversion circuit 30G, it notifies the processor 20 of a change notification indicating that the photoelectric conversion circuit 30A has been changed to the photoelectric conversion circuit 30G as the target for packet input / output. Based on this change notification, the processor 20 changes the input / output port 21A to the input / output port 21G as the destination for packet input / output. In other words, the processor 20 processes the electrical signals converted and output by the photoelectric conversion circuit 30G as if they were electrical signals output by the photoelectric conversion circuit 30A. For example, the processor 20 changes the port number of input / output port 21A in the address table to the port number of input / output port 21G.

[0035] The controller 50 may, upon detecting a failure in the photoelectric conversion circuit 30A, notify the processor 20 of the failure as a failure notification. The processor 20 temporarily stores in the buffer memory 22 packets that were generated between receiving this failure notification and receiving the change notification above, which are to be output to the input / output port 21A. The buffer memory 22 is built into the processor 20 in this case, but it may also be externally connected to the processor 20. After receiving the change notification, the processor 20 outputs the packets stored in the buffer memory 22 from the input / output port 21G.

[0036] As described above, the signal processing device 10 according to this embodiment includes an optical switch 40, photoelectric conversion circuits 30A to 30H, and a processor 20. The optical switch 40 has a plurality of input / output ports 42A to 42F and a plurality of input / output ports 41A to 41H, and outputs a first optical signal input to any of the input / output ports 42A to 42F from any of the input / output ports 41A to 41H. Each of the photoelectric conversion circuits 30A to 30H is connected to an input / output port 41A to 41H, and converts the first optical signal from the connected input / output port among the input / output ports 41A to 41H into a first electrical signal. The processor 20 processes the first electrical signal converted by any of the photoelectric conversion circuits 30A to 30H. The plurality of photoelectric conversion circuits 30A to 30H include the active system photoelectric conversion circuits 30A to 30F and the backup system photoelectric conversion circuits 30G to 30H. When one of the photoelectric conversion circuits 30A to 30F, for example photoelectric conversion circuit 30A, fails, the optical switch 40 connects input / output port 42A, which is connected to input / output port 41A to which photoelectric conversion circuit 30A is connected, to input / output ports 41G or 41H to which the backup photoelectric conversion circuits 30G or 30H are connected, respectively, and outputs the first optical signal input to input / output port 42A from input / output port 41G or 41H. In other words, the first optical signal is converted into an electrical signal by either photoelectric conversion circuit 30G or 30H, input to processor 20, and processed.

[0037] In the above configuration, redundancy of the photoelectric conversion circuits is ensured by the backup photoelectric conversion circuits 30G and 30H. This improves the reliability and robustness of the signal processing device 10. Furthermore, the optical switch 40 allows switching from the faulty active photoelectric conversion circuit to the backup photoelectric conversion circuit without changing the input / output port to which the optical signal is input, thus maintaining the connection between the signal processing device 10 and the outside world. As a result, for example, packet transfer by a user terminal or computing device connected to the input / output port connected to the faulty active photoelectric conversion circuit can continue without long-term downtime. Also, as will be described later, the processor 20 and the photoelectric conversion circuits 30A to 30H can be mounted on a single chiplet substrate such as a Co-Packaged Assemble Substrate. In such cases, since it is difficult to replace each photoelectric conversion circuit, the provision of backup photoelectric conversion circuits 30G and 30H makes it possible to address photoelectric conversion circuit failures without replacing the photoelectric conversion circuits.

[0038] Furthermore, the signal processing device 10 further includes a controller 50 that detects failures in the active photoelectric conversion circuits 30A to 30F. When the controller 50 detects a failure, it controls the optical switch 40 to connect the input / output port 42A to 42F that was connected to the failed photoelectric conversion circuit to the input / output port 41G or 41H connected to the backup photoelectric conversion circuit 30G or 30H. This configuration makes it easy to switch from the failed photoelectric conversion circuit to the backup photoelectric conversion circuit. The controller 50 can also control at least one of the following various operations (including power supply control) of the processor 20, photoelectric conversion circuits 30A to 30H, optical switch 40, etc.

[0039] Furthermore, the backup photoelectric conversion circuits 30G and 30H are powered off when none of the active photoelectric conversion circuits 30A to 30F are faulty, and are activated (powered on) when any of the active photoelectric conversion circuits 30A to 30F fail. With this configuration, the backup photoelectric conversion circuits 30G and 30H do not operate when none of the active photoelectric conversion circuits 30A to 30F are faulty. During the period when they are not operating, the backup photoelectric conversion circuits 30G and 30H are less likely to fail. Therefore, this configuration ensures greater redundancy of the photoelectric conversion circuits. Instead of the controller 50 turning off the power to a faulty photoelectric conversion circuit, the photoelectric conversion circuit may autonomously turn off. The photoelectric conversion circuits 30G and 30H may be in a standby state instead of being powered off during normal operation. In this case, the photoelectric conversion circuits 30G and 30H are activated when any of the active photoelectric conversion circuits 30A to 30F fail, by transitioning from a standby state to an operational state. By putting the photoelectric conversion circuits 30G and 30H into a standby state, the startup is accelerated. These controls are performed by the controller 50. The standby state is not a state where the power is completely turned off, but rather a so-called thermal standby or thermal standby state, which is a non-operating state that is less prone to failure, similar to when the power is turned off.

[0040] Furthermore, when any of the active photoelectric conversion circuits 30A to 30F fail, the processor 20 processes the electrical signal converted and output by the backup photoelectric conversion circuit 30G or 30H, which operates in place of the failed active photoelectric conversion circuit, as the first electrical signal. This allows the processor 20 to operate without changing the connection relationship between the input / output ports 20A to 20H and the photoelectric conversion circuits 30A to 30H.

[0041] The optical switch 40 includes an optical coupler 43A that distributes the first optical signal input to input / output port 42A to input / output port 42A and connection terminal 44A. The optical switch 40 also includes optical couplers 43B to 43F that distribute the first optical signal input to input / output ports 42B to 42F, respectively. For example, when the photoelectric conversion circuit 30A fails, the optical switch 40 connects input / output port 42A and input / output port 41G by connecting connection terminal 44A to input / output port 41G. With this configuration, input / output ports 41A to 41F and input / output ports 42A to 42F, which are connected to the active system's photoelectric conversion circuits 30A to 30F, are connected via passive optical couplers 43A to 43F without going through an active switch section. Since passive optical couplers 43A to 43F generally have a low failure rate, the reliability of the optical path of the active system's optical signal is increased.

[0042] The optical switch 40 may be configured to individually and actively switch the connections between input / output ports 41A to 41H and input / output ports 42A to 42F. In such a case, the optical switch 40 may include devices such as a PLC (Planar Lightwave Citcuit) or a thermal switching type optical switch. The optical switch 40 may be composed of an N x M matrix switch. The optical switch 40 may consist of a combination of multiple 1 x N optical switches with different or the same specifications.

[0043] Furthermore, as described above, the processor 20 processes the first electrical signal and inputs the second electrical signal, which is an electrical signal indicating the processing result (a packet with the header analyzed), to one of the multiple photoelectric conversion circuits 30A to 30H, for example, photoelectric conversion circuit 30C. In addition, the photoelectric conversion circuit 30C, which has the second electrical signal input, converts this second electrical signal into a second optical signal and inputs the converted second optical signal to the input / output port 41C to which the photoelectric conversion circuit 30C is connected. The optical switch 40 outputs the second optical signal from the input / output port 42C connected to the input / output port 41C to which the second optical signal has been input. With this configuration, the conversion of the second electrical signal indicating the processing result into an optical signal can also be performed by the photoelectric conversion circuit.

[0044] Further, when any one of the active optical conversion circuits 30A to 30F, for example, the optical conversion circuit 30A fails, the processor 20 holds the second electrical signal output to the failed optical conversion circuit 30A in the buffer memory 22. After the optical switch 40 connects the input / output port 42A and the input / output port 41G or 41H, the processor 20 outputs the held second electrical signal to the standby optical conversion circuit 30G or 30H connected to the connected input / output port 41G or 41H. With such a configuration, data loss due to the inability to transmit the second electrical signal caused by the failure of the optical conversion circuit 30A is suppressed, and the reliability and robustness of the signal processing device 10 are improved.

[0045] Further, the first optical signal and the first electrical signal represent a packet, and the processor 20 transfers the packet to the address specified by the header of this packet by processing the first electrical signal. Thereby, the signal processing device 10 operates as a network switch.

[0046] As shown in FIG. 3, the signal processing device 10 may include an electrical switch 60 that switches an electrical path between the processor 20 and the optical conversion circuits 30A to 30H. Here, it is assumed that the processor 20 has input / output ports 21A to 21F.

[0047] The electrical switch 60 includes input / output ports 61A to 61F electrically connected to the input / output ports 21A to 21F of the processor 20, respectively, and input / output ports 62A to 62H electrically connected to the optical conversion circuits 30A to 30H, respectively. In the electrical switch 60, normally, the input / output port 61A is electrically connected to the input / output port 62A, and similarly, the input / output ports 61B to 61F are electrically connected to the input / output ports 62B to 62F, respectively. The electrical switch 60 switches the connection relationship between the input / output ports 61A to 61F and the input / output ports 62A to 62H (at least a part of the electrical path between them), in other words, the connection relationship between the input / output ports 21A to 21F of the processor 20 and the optical conversion circuits 30A to 30H (at least a part of the electrical path between them).

[0048] Here, assume that the active photoelectric conversion circuit 30A fails, and the photoelectric conversion circuit 30G is used instead of the photoelectric conversion circuit 30A. In such a case, in addition to the above processing, the controller 50 switches the connection destination of the input / output port 61A connected to the photoelectric conversion circuit 30A via the input / output port 62A from the input / output port 62A to the input / output port 62G to which the photoelectric conversion circuit 30G is connected (see the dotted line in FIG. 3).

[0049] As described above, when any one of the active photoelectric conversion circuits 30A to 30F fails, the electric switch 60 connects the standby photoelectric conversion circuit 30G or 30H and any one of the input / output ports 21A to 21F of the processor 20 to which any one of the failed photoelectric conversion circuits 30A to 30F was connected. With such a configuration, the same number of photoelectric conversion circuits as the number of input / output ports of the processor 20 can be prepared as the active system, and the number of photoelectric conversion circuits exceeding the number of input / output ports of the processor 20 can be prepared as the standby system.

[0050] The specific configuration of the signal processing device 10 is arbitrary, and an example thereof will be briefly described below. Here, the signal processing device 10 is assumed to have 14 active photoelectric conversion circuits and 2 standby photoelectric conversion circuits. Also, in the following, the processor side is the input, and the side of the input / output port 42A of the optical switch etc. is the output. The optical switch is configured to individually and actively switch each connection between the input / output ports 41A etc. on the input side and the input / output ports 42A etc. on the output side. When the configuration of FIG. 1 is adopted as the optical switch, the number of switches etc. and the optical wiring structure below may be changed by the amount by which the number of input / output ports to be switched is reduced.

[0051] The processor can be Broadcom's TOMAHAWK5. The photoelectric conversion circuit conforms to the OIF-Co-Packaging-3.2T-Module-01.0 specification, and the optical interface type supported by the standard 8 x 400GBASE-DR4 (with 32 Tx / Rx fiber pairs) is adopted. As for the optical switch, a 1xN optical switch from DiCon can be used. The optical switch is composed of multiple switches with different specifications. Examples of multiple switches include the MEMS MULTI-MODE 1XN OPTICAL SWITCH 1xN switch (lineup N=2 to 24) and the MEMS 1XN OPTICAL SWITCH 1xN (lineup N=2 to 128).

[0052] The processor actually has 2048 electrical input / output terminals, of which 128 terminals are connected to 16 photoelectric conversion circuits, including both active and backup systems. Each photoelectric conversion circuit has 32 differential transmit terminal pairs and 32 differential receive terminal pairs (128 terminals in total). Each photoelectric conversion circuit is mounted together with the processor on a chiplet substrate, such as a Co-Packaged Assemble Substrate. The photoelectric conversion circuits and the processor are communicated via an electrical transmission path (in other words, a short-range electrical interface) formed on this chiplet substrate.

[0053] The photoelectric conversion circuit has 64 fiber strands connected, with four transmitting and four receiving strands each forming a 400GBASE-DR4 interface. These two interfaces together form a total 800Gbps interface (unidirectional speed). The optical fibers connected to the photoelectric conversion circuit are terminated with, for example, male MPO optical connectors.

[0054] The optical switch has a box-type housing configuration, for example, and can have the following configuration. A female-to-female MPO connector is attached to the housing of the optical switch. An MPO optical connector of an optical fiber connected to a photoelectric conversion circuit is connected to this MPO connector. Inside the housing of the female-to-female MPO connector, a male connector of an MPO with a 1:16 breakout (fanout) structure, which divides the optical fiber into individual fiber strands, is connected. Each of the 16 broken-out optical fibers is connected to one of the input terminals of a 1 (output) x 3 (input) optical switch. The optical connectors at the end of the breakouts are small connectors such as LC connectors, or the 1 (output) x 3 (input) optical switch and the breakout cable are fusion-spliced ​​at the individual fiber strand level for optical connection. There are 14 1:16 breakout cables and 224 (14 x 16) 1 (output) x 3 (input) optical switches.

[0055] For the backup photoelectric conversion circuit, the output terminals of a 1 (output) x 14 (input) optical switch are connected to the broken-out optical fiber. Then, the 14 input terminals of this 1 (output) x 14 (input) optical switch are connected to one of the input terminals of the active 1 (output) x 3 (input) optical switch, to which two backup photoelectric conversion circuits are connected. Since there are two backup photoelectric conversion circuits connected to the optical switch in this case, the input terminals of the active 1 (output) x 3 (input) optical switch are connected to the active photoelectric conversion circuit and the two backup photoelectric conversion circuits.

[0056] In this configuration, the output side of the optical switch has the output of a 1 (output) x 3 (input) optical switch. More specifically, as mentioned above, for each of the 14 active photoelectric conversion circuits, there are 224 of these 1 (output) x 3 (input) optical switches connected to each of the 16 breakout fibers per fiber strand. Therefore, when outputting at the 800Gbps interface level, it is necessary to return from the 16 branches to a single MPO connector. For this reason, 14 1:16 breakout optical cables (MPO) are used inside the output side of the optical switch to convert the outputs of the 224 1 (output) x 3 (input) optical switches to 14 MPOs.

[0057] If the signal processing device 10 with the above configuration is made into a packet switch with 64 ports, then the switch will have 64 ports of 800Gbps paired interfaces (56-port packet switch since there are two backup photoelectric conversion circuits), and from each port of the packet switch, for example, two 400GBASE-DR4 interfaces can be broken out using optical cables (in the case of fiber optics, eight strands for transmission and reception bundled together in a ribbon shape).

[0058] The electrical switch, for example, has a 1 (output) x 3 (input) electrical switch on the side connected to the processor, and its output terminals are connected to input / output ports connected to the active system's photoelectric conversion circuit. The remaining two output terminals are connected to the input terminals of a 1 (output) x 16 (input) electrical switch, which is connected to the input / output ports connected to the backup system's photoelectric conversion circuit. The output side of the 1 (output) x 16 (input) electrical switch is connected to the input / output terminals of the electrical switch connected to the backup system's photoelectric conversion circuit.

[0059] For switching the connection relationships between input / output ports and optical switches, for example, a TTL (Transistor-Transistor Logic) switch switching signal is used. The controller 50 controls this switch switching signal.

[0060] (Second Embodiment) In the second embodiment, an active system and a backup system are provided for the light source of the reference light supplied to the photoelectric conversion circuit. The signal processing device 110 according to the second embodiment will be described below with reference to Figure 4, focusing on the differences from the signal processing device 10.

[0061] The signal processing device 110 includes, in addition to the processor 20, photoelectric conversion circuits 30A to 30H, optical switch 40, controller 50, and electrical switch 60 described in the first embodiment, light sources 171 to 174, optical couplers 181 to 184, optical couplers 185A to 185F, and an optical switch 190 for the light sources.

[0062] Light sources 171-174 emit reference light used in photoelectric conversion circuits 30A-30H. Optical couplers 181-184 are 1 (input):2 (output) optical couplers. Each input of optical couplers 181-184 is optically connected to light sources 171-174, respectively.

[0063] One of the two outputs of optical coupler 181 is optically connected to one of the two inputs of optical coupler 185A (2 inputs:1 output). The other output is optically connected to one of the two inputs of optical coupler 185B (2 inputs:1 output). One of the two outputs of optical coupler 182 is optically connected to one of the two inputs of optical coupler 185C (2 inputs:1 output). The other output is optically connected to one of the two inputs of optical coupler 185D (2 inputs:1 output). One of the two outputs of optical coupler 183 is optically connected to one of the two inputs of optical coupler 185E (2 inputs:1 output). The other output is optically connected to one of the two inputs of optical coupler 185F (2 inputs:1 output).

[0064] The other input of each optical coupler 185A to 185F is optically connected to the output ports 192A to 192F of the optical switch 190, respectively. The respective outputs of each optical coupler 185A to 185F are optically connected to the photoelectric conversion circuits 30A to 30H, respectively. The two outputs of optical coupler 184 are optically connected to the input ports 191A and 191B of the optical switch 190, respectively. The output ports 192G and 192H of the optical switch 190 are optically connected to the photoelectric conversion circuits 30G and 30H, respectively.

[0065] The optical switch 190 switches the connection between input ports 191A and 191B and output ports 192A to 192H (at least a portion of the optical path between them). The optical switch 190 consists of, for example, a combination of 1 x N optical switches. For example, the inputs of a 1 (input) x 8 (output) optical switch are connected to each of input ports 191A and 191B. Each of input ports 191A and 191B actually has 64 terminals, and the 1 (input) x 8 (output) optical switches are provided in proportion to the number of terminals. In addition, the output side of a 1 (output) x 2 (input) optical switch is connected to each of output ports 192A to 192H (physically, each of the 8 x 64 terminals). The output side of the 1 (input) x 8 (output) optical switch connected to input ports 191A and 191B is connected to the input side of this 1 (output) x 2 (input) optical switch.

[0066] In this embodiment, the photoelectric conversion circuits 30A to 30H do not have the light source L shown in Figure 2. The reference light supplied to the photoelectric conversion circuits 30A to 30H is supplied from light sources 171 to 174 as external light sources. Of the light sources 171 to 174, light sources 171 to 173 are the light sources of the active system. Light source 174 is the light source of the backup system.

[0067] The reference light emitted from the light source 171 is split into two by the optical coupler 181. One of the split reference light beams is input to the photoelectric conversion circuit 30A via the optical coupler 185A. The other of the split reference light beams is input to the photoelectric conversion circuit 30B via the optical coupler 185B.

[0068] The reference light emitted from the light source 172 is split into two by the optical coupler 182. One of the split reference light beams is input to the photoelectric conversion circuit 30C via the optical coupler 185C. The other of the split reference light beams is input to the photoelectric conversion circuit 30D via the optical coupler 185D.

[0069] The reference light emitted from the light source 173 is split into two by the optical coupler 183. One of the split reference light beams is input to the photoelectric conversion circuit 30E via the optical coupler 185E. The other of the split reference light beams is input to the photoelectric conversion circuit 30F via the optical coupler 185F.

[0070] The reference light emitted from the light source 174 is split into two by the optical coupler 184. The two split reference lights are input to the input ports 191A and 191B of the optical switch 190, respectively. When none of the light sources 171 to 173 are malfunctioning, the optical switch 190 connects the input ports 191A and 191B to the output ports 192G and 192H, respectively. The reference light emitted from the light source 174 is input to the photoelectric conversion circuits 30G and 30H via the output ports 192G and 192H.

[0071] As can be seen from the above configuration, each of the light sources 171 to 174 is shared by two photoelectric conversion circuits (i.e., 800 Gbps x 4 x 2 = 6.4 Tbps). Each of the light sources 171 to 174 emits reference light from, for example, eight optical fiber strands. The number of terminals on each port of the optical switch 190 corresponds to the number of these optical fiber strands.

[0072] The above optical connections can be made using polarization-maintaining fiber. The optical switch 190 can be configured by combining DiCon's MEMS ML1 1x8 or MEMS MLC 1x4, which utilize polarization-maintaining fiber.

[0073] When light sources 171 to 173 are functioning normally and not malfunctioning, the controller 50 turns on the power to light sources 171 to 173 and inputs reference light to the photoelectric conversion circuits 30A to 30H. Light source 174 is normally powered off and may be powered on when any of light sources 171 to 173 malfunctions.

[0074] In addition to controlling the above embodiment (packet forwarding process, switching to the backup photoelectric conversion circuit 30G or 30H when any of the active photoelectric conversion circuits 30A to 30F fail), the controller 50 performs the following controls.

[0075] The controller 50 monitors the operation of the light sources 171 to 173. For example, the light sources 171 to 173 periodically output a life signal. The controller 50 detects a failure of a light source when the reception of this life signal is interrupted. The controller 50 may also monitor the intensity of the reference light emitted by each of the light sources 171 to 173 using an optical sensor (not shown). The controller 50 detects a light source whose intensity falls below a predetermined threshold as a faulty light source. Alternatively, another controller may be provided to monitor the operation of the light sources 171 to 173 in any way, and the controller 50 may detect a faulty light source based on information from this other controller (for example, important fault information that requires the operation of the light source to be stopped).

[0076] When the controller 50 detects a failure in any of the light sources 171 to 173, it turns off the power to the faulty light source to stop its operation, and turns on the power to light source 174 to start it up. In the following explanation, it is assumed that light source 171 has failed. In this case, the reference light to the photoelectric conversion circuits 30A and 30B is stopped.

[0077] The controller 50 controls the optical switch 190 and connects the input ports 191A and 191B to the output ports 192A and 192B, which are connected to the photoelectric conversion circuits 30A and 30B to which the faulty light source 171 supplies reference light (see dotted lines in Figure 4). As a result, reference light from the backup light source 174 is supplied to the photoelectric conversion circuits 30A and 30B via input ports 191A and 191B → output ports 192A and 192B → optical couplers 185A and 185B. This ensures a supply of reference light.

[0078] The controller 50 may supply the processor 20 with a fault notification indicating a failure in the photoelectric conversion circuits 30A to 30F, and a change notification indicating that the processing of the aforementioned change to the light source has been completed. The processor 20 temporarily stores in the buffer memory 22 packets that were output to the input / output port 21A between the time it receives the fault notification and the time it receives the change notification. After receiving the change notification, the processor 20 resumes outputting the packets stored in the buffer memory 22.

[0079] As described above, the signal processing device 110 includes a processor 20 that processes a first electrical signal and outputs a second electrical signal indicating the processing result, active light sources 171 to 173 that emit a first reference light, a backup light source 174 that emits a second reference light, and photoelectric conversion circuits (here, electro-optical conversion circuits) 30A to 30F that convert the second electrical signal into an optical signal by modulating the first reference light from any of the light sources 171 to 173 based on the second electrical signal from the processor 20. The signal processing device 110 further includes an optical switch 190. When any of the light sources 171 to 173 fails, the optical switch 190 connects the light source 174 to one of the photoelectric conversion circuits 30A to 30F to which the first reference light from the failed light source is input, thereby inputting the second reference light as the first reference light to one of the photoelectric conversion circuits 30A to 30F.

[0080] In the above configuration, the backup light source 174 ensures redundancy for the light source emitting the reference light. This improves the reliability and robustness of the signal processing device 110. Furthermore, it eliminates the need to change the photoelectric conversion circuit used to the backup system in the event of a light source failure. In addition, repairs to the light source become unnecessary, and the connection between the signal processing device 110 and the outside can be maintained. As a result, for example, packet processing from a user terminal or computing device connected to an input / output port connected to a photoelectric conversion circuit connected to a failed primary light source can continue without long-term downtime.

[0081] Furthermore, the signal processing device 110 further includes a controller 50 that detects failures in the light sources 171 to 173. When a failure is detected, the controller 50 controls the optical switch 190 to optically connect one of the photoelectric conversion circuits 30A to 30F, which receive the first reference light from the failed light source, to the light source 174. This configuration makes it easy to switch from the failed light source to the backup light source 174. The controller 50 can also control at least one of the following operations (including power supply control) of the processor 20, photoelectric conversion circuits 30A to 30H, optical switch 190, and light sources 171 to 174.

[0082] Furthermore, light source 174 is powered off when none of light sources 171 to 173 are faulty, and starts up (powers on) when any of light sources 171 to 173 fail. With this configuration, the backup light source 174 does not operate when none of the active light sources 171 to 173 are faulty. During the period when it is not operating, light source 174 is less likely to fail. Therefore, this configuration ensures greater redundancy of the light sources. Instead of the controller 50 turning off the power to a faulty light source 174, light source 174 may autonomously turn off. Note that light source 174 may be in a standby state instead of being powered off during normal operation. In this case, light source 174 starts up by transitioning from the standby state to the operating state when any of the active light sources 171 to 173 fail. By putting light source 174 in a standby state, startup is faster. These controls are performed by the controller 50. The standby state is not a complete power-off state, but rather a so-called thermal standby or thermal standby state, and is a non-operational state that is less prone to failure, similar to when the power is off.

[0083] The processor 20 may hold the second electrical signal to be output to one of the photoelectric conversion circuits 30A to 30F (hereinafter also referred to as the target photoelectric conversion circuit) that receives the first reference light from one of the failed light sources 171 to 173 when any of the light sources 171 to 173 fails. The processor 20 also outputs the held second electrical signal to the target photoelectric conversion circuit after the optical switch 190 connects one of the photoelectric conversion circuits 30A to 30F to the light source 174. With this configuration, data loss due to the inability to transmit the second electrical signal caused by a failure of any of the light sources 171 to 173 is suppressed, and the reliability and robustness of the signal processing device 110 are improved.

[0084] Furthermore, light source 171 and photoelectric conversion circuits 30A and 30B are connected via optical couplers 185A and 185B, respectively; light source 172 and photoelectric conversion circuits 30C and 30D are connected via optical couplers 185C and 185D, respectively; and light source 172 and photoelectric conversion circuits 30E and 30F are connected via optical couplers 185E and 185F, respectively. The optical switch 190 connects light source 174 to optical couplers 185A and 185B, optical couplers 185C and 185D, or optical couplers 185E and 185F. As a result of this connection, a second reference light from light source 174 is input to the photoelectric conversion circuit connected to the optical coupler to be connected. In this configuration, the light source 171 of the active system and the photoelectric conversion circuits 30A to 30F of the active system are connected via passive optical couplers 185A to 185F, respectively, without the need for an active switch. Since passive optical couplers 185A to 185F generally have a low failure rate, the reliability of the conversion to optical signals of the active system is increased.

[0085] Furthermore, the aforementioned first optical signal represents a packet, and the processor 20 processes the first electrical signal to forward the packet to the address specified by the packet's header. In this way, the signal processing device 110 operates as a network switch.

[0086] The signal processing device 110 according to the second embodiment can be changed to the signal processing device 210 shown in Figure 5. The signal processing device 210 includes an optical switch 290 instead of an optical switch 190. In the signal processing device 210, the two outputs of an optical coupler 181 whose input is connected to a light source 171 are connected to input ports 291A and 291B of the optical switch 290, respectively. The two outputs of an optical coupler 182 whose input is connected to a light source 172 are connected to input ports 291C and 291D of the optical switch 290, respectively. The two outputs of an optical coupler 183 whose input is connected to a light source 173 are connected to input ports 291E and 291F of the optical switch 290, respectively. The two outputs of an optical coupler 184 whose input is connected to a light source 174 are connected to input ports 291G and 291H of the optical switch 290, respectively.

[0087] The optical switch 290 includes output ports 292A to 292H, which are connected to the photoelectric conversion circuits 30A to 30H, respectively. The optical switch 290 switches the connection between the input ports 291A to 291H and the output ports 292A to 292H (at least a portion of the optical path between them). The optical switch 290 includes, for example, an 8x8 optical matrix switch. This 8x8 optical matrix switch is composed of a combination of 1x8 optical switches.

[0088] In the optical switch 290, under normal conditions, the input ports 291A to 291H and the output ports 292A to 292H are connected, respectively. That is, the reference light from the light source 171 is supplied to the photoelectric conversion circuits 30A and 30B, respectively. The reference light from the light source 172 is supplied to the photoelectric conversion circuits 30C and 30D, respectively. The reference light from the light source 173 is supplied to the photoelectric conversion circuits 30E and 30F, respectively. The reference light from the light source 174 is supplied to the photoelectric conversion circuits 30G and 30H, respectively.

[0089] Here, we will describe the operation when any of the light sources 171 to 173 of the active system fail. For example, when the controller 50 detects a failure in light source 171, it controls the power supply of light source 174 from off to on, and also controls the optical switch 290 to switch the connections between input ports 291A and 291B and output ports 292A and 292B to connections between input ports 291G and 291H and output ports 292A and 292B. As a result, light source 174 is optically connected to photoelectric conversion circuits 30A and 30B, and reference light from light source 174 is input to them instead of reference light from light source 171.

[0090] For example, light sources 171 to 173 may continue to output light even if they have failed. In the example in Figure 4, for example, the light output from light source 171 during a failure is input to photoelectric conversion circuits 30A and 30B, so it is desirable to turn off the power to light source 171. However, in the example in Figure 5, the optical switch 290 disconnects the optical connection between light source 171 and photoelectric conversion circuits 30A and 30B. In this way, the optical switch 190 connects photoelectric conversion circuits 30A and 30B to light source 171 before light source 171 fails, and when light source 171 fails, it disconnects the connection between photoelectric conversion circuit 30A and light source 171, and connects photoelectric conversion circuit 30A to light source 174. This eliminates the need to turn off the power to the failed active light source and enables a quick switch to the backup light source.

[0091] Furthermore, in the example shown in Figure 5, light sources 171 to 174 can be used without distinction between the active and backup systems. Moreover, for example, if light source 171 fails, it can be replaced with a new light source while backup light source 174 is being used. This new light source may be used as the backup light source or restored as the active light source (in this case, the state of the optical switch 190 is restored to the state before the failure). As explained above, by using a configuration like that shown in Figure 5, it is possible to resume processing with a short processing downtime in the event of a light source failure. It also has the advantage of improving operational flexibility, such as being able to return to the previous state after replacing a light source.

[0092] As shown in Figure 6, the photoelectric conversion circuit 30A may be packaged together with the internal light source L of the current system as a single module M (for example, a CPO (Co-packaged Optical) type module). In this case, the photoelectric conversion circuit 30A and the internal light source L are housed in a single housing 39 of the module M. In addition to the photoelectric conversion element 31, converter 32, control circuit 33, driver circuit 34, and modulator 35 described above, the photoelectric conversion circuit 30A further comprises a 2 (input):1 (output) optical coupler 38. The two inputs of the optical coupler 38 are connected to the internal light source L and the output port 292A of the optical switch 290 in Figure 5. The output of the optical coupler 38 is optically connected to the modulator 35. The optical coupler 38, modulator, and optical waveguide can be formed, for example, by glass waveguide formation technology using silicon photonics technology.

[0093] The photoelectric conversion circuits 30B to 30H have the same configuration as the photoelectric conversion circuit 30A. However, the respective connection destinations of the optical couplers 38 of the photoelectric conversion circuits 30B to 30H are output ports 292B to 292H. When the configuration shown in Figure 6 is adopted, each of the external light sources, light sources 171 to 174, is provided as a backup system.

[0094] For example, if the internal light source L of the photoelectric conversion circuit 30A fails, the controller 50 detects this in any way it chooses. For example, the failure is detected by monitoring a life signal from the internal light source L or by various information from the photoelectric conversion circuit 30A. In this case, the controller 50 controls the photoelectric conversion circuit 30A and turns off the power to the internal light source L. The controller 50 also turns on the power to the light source 171 and controls the optical switch 290 to connect the input port 291A and the output port 292A. As a result, the reference light from the light source 171 is input to the modulator 35 via the optical switch 290 and the optical coupler 38. The modulator 35 modulates the reference light to convert it into an optical signal.

[0095] As described above, the photoelectric conversion circuit 30A is packaged together with the internal light source L of the active system as a single module M (for example, a CPO (Co-packaged Optical) type module), which facilitates the manufacturing of the signal processing device. Furthermore, if the internal light source L of module M fails, one of the external light sources 171 to 174 is used. This makes it possible to provide redundancy for the light sources of module M, which have a particularly high failure rate, thereby improving the reliability of the signal processing device.

[0096] (Modifications) The above embodiments are examples of applying the present invention to a network switch, but the present invention is applicable to various signal processing devices.

[0097] (Note) Methods and configurations that use all or part of the above embodiments and modifications as examples are described below.

[0098] (Note 1) A signal processing device comprising: an optical switch having a plurality of input ports and a plurality of output ports, which outputs a first optical signal input to any of the plurality of input ports from any of the plurality of output ports; a plurality of photoelectric conversion circuits connected to each of the plurality of output ports, which convert the first optical signal from the connected output port among the plurality of output ports into a first electrical signal; and a processor which processes the first electrical signal converted by any of the plurality of photoelectric conversion circuits, wherein the plurality of photoelectric conversion circuits include a first active photoelectric conversion circuit connected to a first output port among the plurality of output ports, and a second backup photoelectric conversion circuit connected to a second output port among the plurality of output ports, and the optical switch connects a first input port connected to the first output port among the plurality of input ports to the second output port when the first photoelectric conversion circuit fails. (Note 2) The signal processing device according to Note 1, further comprising a controller for detecting a failure of the first photoelectric conversion circuit, wherein the controller controls the optical switch to connect the first input port and the second output port when it detects the failure. (Note 3) The signal processing device according to Note 1 or 2, wherein the second photoelectric conversion circuit is powered off or in standby mode when the first photoelectric conversion circuit is not faulty, and is activated when the first photoelectric conversion circuit fails. (Note 4) The signal processing device according to any one of Notes 1 to 3, wherein the processor processes the electrical signal converted and output by the second photoelectric conversion circuit as the first electrical signal when the first photoelectric conversion circuit fails. (Note 5) The signal processing device according to any one of Notes 1 to 4, wherein the optical switch includes an optical coupler that distributes the first optical signal input to the first input port to the first output port and a connection terminal, and connects the first input port and the second output port by connecting the connection terminal and the second output port when the first photoelectric conversion circuit fails.(Note 6) The signal processing device according to any one of Notes 1 to 5, wherein the processor is connected to a signal input port to which the first photoelectric conversion circuit is connected and to which the first electrical signal from the first photoelectric conversion circuit is input, and further comprises an electrical switch that connects the second photoelectric conversion circuit and the signal input port when the first photoelectric conversion circuit fails. (Note 7) The signal processing device according to any one of Notes 1 to 6, wherein the processor processes the first electrical signal and inputs a second electrical signal, which is the electrical signal after processing or an electrical signal indicating the processing result, to one of the plurality of photoelectric conversion circuits, the photoelectric conversion circuit to which the second electrical signal is input converts the second electrical signal into a second optical signal, and inputs the converted second optical signal to an output port among the plurality of output ports to which the photoelectric conversion circuit is connected, and the optical switch outputs the second optical signal from an input port among the plurality of input ports that is connected to the output port to which the second optical signal is input. (Note 8) The signal processing device according to Note 7, wherein the processor holds the second electrical signal to be output to the failed first photoelectric conversion circuit when the first photoelectric conversion circuit fails, and outputs the held second electrical signal to the second photoelectric conversion circuit after the optical switch connects the first input port and the second output port. (Note 9) The signal processing device according to Note 7, further comprising: a first light source of an active system that emits first light; a second light source of a backup system that emits second light; and an optical switch for the light source, wherein the first photoelectric conversion circuit converts the second electrical signal into a second optical signal by modulating the first light from the first light source based on the second electrical signal from the processor; and the optical switch for the light source inputs the second light as the first light to the first photoelectric conversion circuit by connecting the first photoelectric conversion circuit and the second light source when the first light source fails. (Note 10) The signal processing apparatus according to any one of Notes 1 to 9, wherein the first optical signal and the first electrical signal represent a packet, and the processor processes the first electrical signal to transfer the packet to the address specified by the packet header.(Note 11) A signal processing device comprising: a processor that processes a first electrical signal and outputs a second electrical signal indicating the processing result; a first light source of an active system that emits a first light; a second light source of a backup system that emits a second light; an electro-optical conversion circuit that converts the second electrical signal into an optical signal by modulating the first light from the first light source based on the second electrical signal from the processor; and an optical switch that connects the electro-optical conversion circuit and the second light source when the first light source fails, thereby inputting the second light as the first light to the electro-optical conversion circuit. (Note 12) The signal processing device according to Note 11, further comprising a controller that detects a failure of the first light source, wherein the controller controls the optical switch to connect the electro-optical conversion circuit and the second light source when it detects the failure. (Note 13) The signal processing device according to Note 11 or 12, wherein the second light source is powered off or in standby mode when the first light source is not faulty, and is activated when the first light source fails. (Note 14) The signal processing device according to any one of Notes 11 to 13, wherein the processor holds the second electrical signal to be output to the faulty photonic conversion circuit when the first light source fails, and outputs the held second electrical signal to the connected photonic conversion circuit after the optical switch connects the photonic conversion circuit and the second light source. (Note 15) The signal processing device according to any one of Notes 11 to 14, wherein the first light source and the photonic conversion circuit are connected via an optical coupler, and the optical switch inputs the second light as the first light to the photonic conversion circuit by connecting the second light source and the optical coupler. (Note 16) The signal processing device according to any one of Notes 11 to 15, wherein the optical switch connects the photonic conversion circuit and the first light source before the first light source fails, and disconnects the connection between the photonic conversion circuit and the first light source and connects the photonic conversion circuit and the second light source when the first light source fails. (Note 17) The signal processing apparatus according to any one of Notes 11 to 16, wherein the first light source and the photoelectric conversion circuit are packaged as a single module, and the second light source is an external light source located outside the single module.(Note 18) The signal processing apparatus according to any one of Notes 11 to 17, wherein the first electrical signal represents a packet, and the processor processes the first electrical signal to forward the packet to the address specified by the packet header.

[0099] (Scope of the Invention) The present invention is not limited to the embodiments and modifications described above. For example, the present invention includes various modifications to the embodiments and modifications described above that can be understood by those skilled in the art within the scope of the technical concept of the present invention. The configurations listed in the embodiments and modifications described above can be combined as appropriate to the extent that they do not contradict each other. It is also possible to delete any of the above configurations.

[0100] 10...Signal processing unit, 20...Processor, 20A-20H, 21A-21H...Input / Output ports, 22...Buffer memory, 30A-30H...Photoelectric conversion circuit, 31...Photoelectric conversion element, 32...Converter, 33...Control circuit, 34...Driver circuit, 35...Modulator, 38...Optical coupler, 39...Housing, 40...Optical switch, 41A-41H...Input / Output ports, 42A-42F...Input / Output ports, 43A-43F...Optical coupler, 44A-44F...Connection terminal, 50...Co Controller, 60...electrical switch, 61A-61F, 62A-62H...input / output port, 110...signal processing device, 171-174...light source, 181-184, 185A-185F...optical coupler, 190...optical switch, 191A-191B...input port, 192A-192H...output port, 210...signal processing device, 290...optical switch, 291A-291H...input port, 292A-292H...output port, L...light source, M...module.

Claims

1. A signal processing device comprising: an optical switch having a plurality of input ports and a plurality of output ports, which outputs a first optical signal input to any of the plurality of input ports from any of the plurality of output ports; a plurality of photoelectric conversion circuits connected to each of the plurality of output ports, which convert the first optical signal from the connected output port among the plurality of output ports into a first electrical signal; and a processor which processes the first electrical signal converted by any of the plurality of photoelectric conversion circuits, wherein the plurality of photoelectric conversion circuits include a first active photoelectric conversion circuit connected to a first output port among the plurality of output ports, and a second backup photoelectric conversion circuit connected to a second output port among the plurality of output ports, and the optical switch connects a first input port connected to the first output port among the plurality of input ports to the second output port when the first photoelectric conversion circuit fails.

2. The signal processing device according to claim 1, wherein the second photoelectric conversion circuit is powered off or in standby mode when the first photoelectric conversion circuit is not malfunctioning, and is activated when the first photoelectric conversion circuit malfunctions.

3. The signal processing device according to claim 1, wherein the optical switch includes an optical coupler that distributes the first optical signal input to the first input port to the first output port and a connection terminal, and connects the first input port and the second output port by connecting the connection terminal and the second output port when the first photoelectric conversion circuit fails.

4. The signal processing apparatus according to claim 1, wherein the processor comprises a signal input port to which the first photoelectric conversion circuit is connected and to which the first electrical signal from the first photoelectric conversion circuit is input, and further comprises an electrical switch for connecting the second photoelectric conversion circuit and the signal input port when the first photoelectric conversion circuit fails.

5. The signal processing apparatus according to claim 1, wherein the processor processes the first electrical signal and inputs a second electrical signal, which is the electrical signal after processing or an electrical signal indicating the processing result, to one of the plurality of photoelectric conversion circuits; the photoelectric conversion circuit that receives the second electrical signal converts the second electrical signal into a second optical signal and inputs the converted second optical signal to an output port among the plurality of output ports to which the photoelectric conversion circuit is connected; the optical switch outputs the second optical signal from an input port among the plurality of input ports that is connected to the output port to which the second optical signal is input; and the processor holds the second electrical signal to be output to the failed first photoelectric conversion circuit when the first photoelectric conversion circuit fails, and outputs the held second electrical signal to the second photoelectric conversion circuit after the optical switch connects the first input port and the second output port.

6. The signal processing device according to claim 5, further comprising: a first light source of an active system that emits a first light; a second light source of a backup system that emits a second light; and an optical switch for the light source, wherein the first photoelectric conversion circuit converts the second electrical signal into a second optical signal by modulating the first light from the first light source based on the second electrical signal from the processor; and the optical switch for the light source connects the first photoelectric conversion circuit and the second light source when the first light source fails, thereby inputting the second light as the first light to the first photoelectric conversion circuit.

7. A signal processing device comprising: a processor that processes a first electrical signal and outputs a second electrical signal indicating the processing result; a first light source of an active system that emits a first light; a second light source of a backup system that emits a second light; an electro-optical conversion circuit that converts the second electrical signal into an optical signal by modulating the first light from the first light source based on the second electrical signal from the processor; and an optical switch that connects the electro-optical conversion circuit and the second light source when the first light source fails, thereby inputting the second light as the first light to the electro-optical conversion circuit.

8. The signal processing apparatus according to claim 7, wherein the optical switch connects the photoelectric conversion circuit and the first light source before the first light source fails, and disconnects the connection between the photoelectric conversion circuit and the first light source and connects the photoelectric conversion circuit and the second light source when the first light source fails.

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