Signal processing device

Abstract

A signal processing device (10) comprises: a main signal line (L10) that transmits CW light and that extends from a connector (21), which is optically connected to a light source (30), to connectors (22A-22D) after passing through a module (50); and a sub-signal line (L20) that branches from the main signal line (L10). The main signal line (L10) includes: a first signal line (L11) connected to the connector (21); and a second signal line (L12) connected to the connectors (22A-22D). The main signal line (L10) includes an optical switch (40) that is disposed between the first signal line (L11) and the second signal line (L12) and that switches the optical connection destination of the first signal line (L11) between the second signal line (L12) and the sub-signal line (L20).

Description

Signal Processing Device

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

[0002] A signal processing device compatible with optical signals (for example, a network switch) is known. A CPO (Co-packaged Optical) module (Non-Patent Document 1) may be used in such a signal processing device.

[0003] https: / / www.oiforum.com / wp-content / uploads / OIF-Co-Packaging-3.2T-Module-01.0.pdf , Implementation Agreement for a 3.2Tb / s Co-Packaged (CPO) Module (published March 29, 2023)

[0004] A signal processing device using a CPO module includes a first connector optically connected to a light source, and a second connector optically connected to an external device of the signal processing device, and it is conceivable that the CPO module is configured to be optically connected to the first connector and the second connector. In such a signal processing device, a main signal line that extends from the first connector through the CPO module to the second connector and transmits an optical signal is formed.

[0005] Conventionally, it has not been possible to extract an optical signal transmitted through this main signal line to the outside of the main signal line. If the optical signal transmitted through this main signal line can be extracted in the middle of the main signal line, for example, the signal state of the optical signal can be inspected.

[0006] An object of the present invention is to make it possible to extract an optical signal transmitted through a main signal line in the middle of the main signal line.

[0007] The signal processing device according to the present invention is a signal processing device comprising: a first connector configured to be optically connected to a light source that emits an optical signal; a second connector configured to be optically connected to an external device of the signal processing device; a CPO (Co-packaged Optical) module optically connected to the first connector and the second connector; and a main signal line extending from the first connector through the CPO module to the second connector to transmit the optical signal, the main signal line including a first signal line connected to the first connector and a second signal line connected to the second connector; and a sub-signal line branching from the main signal line, wherein the main signal line includes an optical switch positioned between the first signal line and the second signal line, which switches the optical connection destination of the first signal line between the second signal line and the sub-signal line.

[0008] With this configuration, the optical signal transmitted by the main signal line can be extracted from the main signal line at some point along its course.

[0009] Figure 1 shows the main configuration of a signal processing device according to an embodiment of the present invention. Figure 2 is a flowchart of the inspection process. Figure 3 shows the main configuration of a modified signal processing device. Figure 4 shows the main configuration of a modified signal processing device. Figure 5 is a flowchart of the inspection process according to a modified example. Figure 6 shows an example of the configuration of a signal state table.

[0010] The signal processing device 10 according to this embodiment, 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 or big data processing). Specifically, the signal processing device 10 is configured to transfer packets from computing devices that constitute the optical network to other computing devices (including network switches) that constitute this optical network. Optical signals are used for packet transfer.

[0011] As shown in Figure 1, the signal processing device 10 includes a connector 21, connectors 22A to 22D (collectively referred to as "22"), a light source 30, an optical switch 40, a module 50, a processing unit 60, an interface 70, and a processor 90. The signal processing device 10 also includes optical waveguides L1 to L3, L4A to L4D (collectively referred to as "L4"), and L5. As an example, connectors 21, connectors 22A to 22D, optical switch 40, module 50, and processing unit 60 are mounted on a substrate (not shown) together with a packet transmission circuit (not shown) described later. Optical waveguides L2 to L5 may be waveguides directly provided on the substrate (for example, slab waveguides), or they may be optical fiber cables with connectors at both ends that are connected to the target object by these connectors. Optical waveguide L1 consists of an optical fiber cable located outside the housing of the signal processing device 10.

[0012] Each element shown in Figure 1 is used when processing and transmitting packets. Packet processing is performed by the processor 90. The actual signal processing device 10 also includes a packet transmission circuit that transmits packets input from any of the external devices EDa to EDd, which are computing devices constituting the optical network and are optically connected to connectors 22A to 22D, to the processor 90, but this circuit is not shown in the diagram. The packet transmission circuit includes a photoelectric conversion element (e.g., a photodiode) that converts packets input as optical signals to any of the connectors 22A to 22D into current signals, and a transimpedance amplifier (TIA) that converts the converted current signals into voltage signals. The packet transmission circuit further includes an A / D (analog / digital) conversion circuit that converts the voltage signals converted by the TIA into analog-to-digital signals. The packet transmission circuit inputs the packets converted into digital signals by the A / D conversion circuit to any of the ports 91A to 91D provided by the processor 90. Ports 91A to 91D and connectors 22A to 22D correspond to each other by the same alphabetical code. Packets input to connector 22A are photoelectrically converted by the packet transmission circuit and input to port 91A, which corresponds to connector 22A. The operation of processor 90 when a packet is input will be described later. Connectors to which packets are input may be provided separately from connectors 22A to 22D. The port of processor 90 to which packets are input may be provided separately from ports 91A to 91D.

[0013] Connectors 21, 22A to 22D, light source 30, and interface 70 penetrate the housing 11 of the signal processing device 10, with a portion of them exposed to the outside of the signal processing device 10. The other elements 30 to 60, 90, and L2 to L5 are housed inside the housing 11 of the signal processing device 10.

[0014] The connector 21 and the light source 30 are optically connected by an optical waveguide L1, which consists of an optical fiber cable located outside the housing 11. The two cable connectors at both ends of the optical waveguide L1 are connected to the portion of the connector 21 exposed from the housing 11 and the portion of the light source 30 exposed from the housing 11, respectively. The connector 21 is optically connected to the optical switch 40 by an optical waveguide L2. The optical switch 40 is optically connected to the module 50 by an optical waveguide L3 and optically connected to the processing unit 60 by an optical waveguide L5. The light source 30 and the optical switch 40 are electrically connected to the processing unit 60 and controlled by the processing unit 60. An interface 70 is connected to the processing unit 60.

[0015] Module 50 is optically connected to connector 22A by optical waveguide L4A. Similarly, module 50 is optically connected to connectors 22B to 22D by optical waveguides L4B to L4D. Connectors 22A to 22D are optically connected to external devices EDa to EDd, respectively, via optical waveguides. Module 50 comprises a substrate 51, a splitter 52, optical modulators 53A to 53D (collectively referred to as "53"), a signal processing circuit 54, optical waveguides 55, 56A to 56D (collectively referred to as "56"), and 57A to 57D (collectively referred to as "57"). Module 50 is a CPO (Co-packaged optics) module, which is packaged using CPO. Specifically, the splitter 52, optical modulators 53A to 53D, and signal processing circuit 54 are mounted on the substrate 51, and the optical waveguides 55 to 57 are directly formed on the substrate 51, for example, as slab waveguides. In this configuration, each element of the module 50 is packaged. The module 50 may also include a housing to accommodate each element. As one form of CPO, there is NPO (Near-Packaged Optics), and the module 50 may take the form of an NPO module as an example of a CPO module. The module 50 also includes a module controller 59, etc.

[0016] The splitter 52 is optically connected to the optical waveguide L3 via the optical waveguide 55. The splitter 52 is optically connected to the downstream (later) optical modulators 53B to 53D via the optical waveguides 56A to 56D. The optical modulators 53B to 53D are optically connected to the optical waveguides L4A to L4D via the optical waveguides 57A to 57D. The signal processing circuit 54 is electrically connected to the optical modulators 53B to 53D and controls them. The signal processing circuit 54 is electrically connected to the module controller 59 and controlled by the module controller 59. The signal processing circuit 54 is also electrically connected to the processor 90.

[0017] The processing unit 60 includes a detector 61 optically connected to the optical waveguide L5, a processor 62 electrically connected to the detector 61, and a memory 63 accessible by the processor 62. The detector 61 includes a variable optical attenuator (VOA) 61A optically connected to the optical waveguide L5, and a photoelectric conversion circuit 61B optically connected to the VOA 61A.

[0018] Optical waveguides L2 to L4, optical switch 40, splitter 52, optical modulator 53, and optical waveguides 55 to 57 constitute the main signal line L10. The main signal line L10 extends from connector 21 to connectors 22A to 22D and transmits CW light from light source 30. The main signal line L10 passes through module 50 because module 50 has a splitter 52, optical modulator 53, and optical waveguides 55 to 57. The main signal line L10 has a first signal line L11 including optical waveguide L2, and a second signal line L12 including optical waveguide L3, splitter 52, optical modulator 53, optical waveguides 55 to 57, and optical waveguides L4A to L4D. One end of the first signal line L11 is connected to connector 21, and the other end is connected to optical switch 40. One end of the second signal line L12 is connected to connectors 22A to 22D, and the other end is connected to the optical switch 40. The optical waveguide L5, which is further connected to the optical switch 40, constitutes the sub-signal line L20 that branches off from the main signal line L10. The optical switch 40 is positioned between the first signal line L11 and the second signal line L12, and switches the optical connection destination of the first signal line L11 to the second signal line L12 and the sub-signal line L20.

[0019] Next, we will explain the details of each of the above elements.

[0020] The light source 30 includes a laser diode and emits CW (Continuous Wave) light, which is an optical signal modulated by the module 50 (optical modulators 53A to 53D), under the control of the processing unit 60.

[0021] CW light from the light source 30 is input to the connector 21 via the optical waveguide L1. The connector 21 is formed in a shape that is optically connected to the light source 30. The CW light input to the connector 21 is input to the optical switch 40 via the optical waveguide L2. The optical switch 40 is a device that can select the optical path. Under the control of the processing unit 60, the optical switch 40 switches the connection destination of the first signal line L11 as described above, thereby distributing the CW light to the module 50 on the second signal line L12 and the processing unit 60 connected to the sub-signal line L20.

[0022] Examples of optical switches 40 include waveguide switches using thermo-optical effects with MEMS (Micro Electro Mechanical Systems), PLC (Planar Lightwave Circuit), or silicon photonics, and waveguide switches using electro-optical effects with compound semiconductors.

[0023] When the optical switch 40 distributes CW light to module 50, the CW light is input to module 50 via optical waveguide L3. The CW light input to module 50 is input to splitter 52 via optical waveguide 55, and splitter 52 distributes it to optical modulators 53A to 53D via optical waveguides 56A to 56D.

[0024] Optical modulators 53A to 53D are individually controlled by the signal processing circuit 54 to modulate CW light. The CW light modulated by optical modulator 53A is input to connector 22A via optical waveguides 57A and L4A, and sent from connector 22A to external device EDa connected to connector 22A. Similarly, the CW light modulated by optical modulators 53B to 53D is input to connectors 22B to 22D via optical waveguides 57B to 57D and L4A to L4D, respectively, and sent to external devices EDb to EDd, respectively.

[0025] The signal processing circuit 54 consists of, for example, one or more IC (Integrated Circuit) chips. Examples of IC chips constituting the signal processing circuit 54 include a DSP (Digital Signal Processor) and a driver IC. The optical modulators 53A to 53D consist of, for example, Mach-Zehnder modulators. Ports 91A to 91D of the processor 90 are electrically connected to the signal processing circuit 54. As described above, the packet transmission circuit is also connected to ports 91A to 91D. For example, the DSP of the signal processing circuit 54 may constitute part of the packet transmission circuit. In this case, only the signal processing circuit 54 is connected to ports 91A to 91D.

[0026] The module controller 59 consists of, for example, one or more IC chips. Examples of IC chips include ASICs (Application Specific Integrated Circuits), FPGAs (Field-Programmable Gate Arrays), DSPs (Digital Signal Processing), CPUs (Central Processing Units), and microcomputers. The module controller 59 is controlled by the processor 62 and controls the operation of the module 50 (particularly the operation of the signal processing circuit 54 and the packet transmission circuit).

[0027] The processor 90 connected to the signal processing circuit 54 consists of a single ASIC chip, also known as a switch ASIC. The processor 90 may also consist of other IC chips on a single chip, such as an FPGA, DSP, CPU, or microcomputer. The processor 90 may also consist of a combination of multiple IC chips.

[0028] Here, the packet forwarding process by the processor 90 will be described. When a packet as an optical signal is input to connector 22A, one of the connectors 22A to 22D, the packet is converted into an electrical signal by the packet transmission circuit and input to the processor 90 from port 91A, which corresponds to connector 22A. The processor 90 refers to the MAC address table and outputs the packet from the port corresponding to the MAC address stored in the header of the input packet, one of the ports 91A to 91D, for example, port 91D. The packet output from port 91D is input to the signal processing circuit 54. The signal processing circuit 54 controls the optical modulator 53D connected to connector 22D, which corresponds to port 91D, the source of the input packet, based on the data (electrical signal) of the packet. The optical modulator 53D, which operates under this control, modulates the CW light input from the splitter 52. The modulated CW light is an optical signal representing the packet. This optical signal is output to the outside from connector 22D. As a result, the electrical signal indicating the packet from the processor 90 is converted into an optical signal and output. The signal processing circuit 54 controls the optical modulators 53A to 53C, other than the one being controlled in this case, so that CW light is not output to the connectors 22A to 22C. As a result, the optical signal is output only from connector 22D. Through the above processing, the signal processing device 10 performs packet forwarding. This packet forwarding process is performed each time a packet is input to any of the connectors 22A to 22D of the signal processing device 10.

[0029] If the optical switch 40 directs the CW light to the processing unit 60 instead of the module 50, the CW light is input to the detector 61 of the processing unit 60 via the optical waveguide L5.

[0030] The CW light input to the detector 61 is first input to the VOA 61A. The photoelectric conversion circuit 61B, located downstream of the VOA 61A, adjusts the light intensity of the CW light input to the VOA 61A to a range that can be processed (for example, by attenuating it). The photoelectric conversion circuit 61B includes a photoelectric conversion element such as a photodiode, a TIA, and an A / D conversion circuit. The photoelectric conversion element converts the input CW light into an analog current signal having a current value corresponding to the light intensity of the CW light. The TIA converts the converted analog current signal into an analog voltage signal. The A / D conversion circuit converts the analog voltage signal into a digital electrical signal and outputs the digital electrical signal to the processor 62. With this configuration, the detector 61 detects the light intensity of the CW light by converting the light intensity into an electrical signal and inputs the detected light intensity (electrical signal) to the processor 62.

[0031] The processor 62 includes a CPU and performs the inspection process by executing the program 63P stored in the memory 63. The processor 62 may consist of one or more IC chips that perform the inspection process. Examples of IC chips include a CPU, ASIC, FPGA, DSP, and microcomputer.

[0032] The processor 62 performs, for example, the inspection process shown in Figure 2. The inspection process is performed, for example, when the signal processing device 10 is started up. The inspection process is for checking whether there is an abnormality in the main signal line L10 or its upstream side. The inspection process may be performed periodically at predetermined intervals after the signal processing device 10 has been started up.

[0033] In the inspection process, the processor 62 first controls the light source 30 to low power mode and controls the optical switch 40 to connect the first signal line L11 and the sub-signal line L20 (step S11). As a result, CW light with a light intensity lower than that used for optical modulation is emitted from the light source 30, and the emitted CW light is input to the processing unit 60 via the sub-signal line L20. Note that if the optical switch 40 is initially connected to the first signal line L11 and the sub-signal line L20, control of the optical switch 40 in step S11 is unnecessary. The CW light input to the processing unit 60 is input to the detector 61. The detector 61 detects the light intensity of the CW light. The detected light intensity (electrical signal) is input to the processor 62. Note that if the light intensity of the CW light in low power mode is weak, the detector 61 does not need to include the VOA 61A.

[0034] The processor 62 acquires the light intensity of the CW light from the detector 61 (step S12) and determines whether the acquired light intensity is normal (step S13). The processor 62 determines that the light intensity is abnormal, i.e., not normal, when the light intensity is lower than a preset threshold (step S13; No). The processor 62 determines that the light intensity is normal when the light intensity is equal to or greater than the threshold (step S13; Yes).

[0035] If the light intensity is abnormal (step S13; No), it means that CW light with the desired light intensity has not reached the detector 61. In this case, there is a possibility that an abnormality has occurred in at least one of the light source 30 and the CW light path (i.e., the signal line through which the CW light was transmitted). The CW light path includes the optical waveguide L1, the connector 21, the first signal line L11 (optical waveguide L2), the optical switch 40, the sub-signal line L20 (optical waveguide L5), and the detector 61. Among the CW light path, the optical waveguide L1 is a place where abnormalities are likely to occur. The optical waveguide L1 is made of an optical fiber cable and is connected to the connection target by a connector during assembly before the signal processing device 10 is started up. Therefore, an abnormality in the optical waveguide L1 may be a faulty connector connection (e.g., a disconnected connector). It is also possible that an abnormality in the optical waveguide L1 is a broken wire or a damaged connector. The same applies to the optical waveguides L2 and L5 when they are made of optical fiber cables. Furthermore, since the optical waveguide L1 is located outside the housing 11, it is susceptible to external forces and is more prone to malfunctions than the optical waveguides L2 and L5.

[0036] If the light intensity is abnormal (step S13; No), the processor 62 controls the light source 30 to terminate its operation, i.e., the emission of CW light (step S14). Furthermore, the processor 62 performs a process to notify the user of abnormal information indicating that there is a possibility of an abnormality occurring in at least one of the light source 30 and the CW light path (step S15). The user includes the user and administrator of the signal processing device 10, as well as the installer of the signal processing device 10. This process includes outputting the abnormal information to the interface 70. The interface 70 includes at least one of a user interface such as a display unit and an operation unit, and a communication interface connected to a predetermined external device. The processor 62 displays the abnormal information on the user interface or on the external device via the communication interface. By confirming this display, the user can recognize the abnormality and take action. The abnormal information may be a message prompting inspection of the optical fiber cable, which is prone to abnormalities (for example, "Please inspect the optical fiber cable"). In particular, the anomaly information may be a message prompting inspection of the optical waveguide L1, i.e., the optical fiber cable connected to the light source 30, where anomalies are most likely to occur (for example, "Please inspect the externally connected optical fiber cable"). Note that failures of the light source 30 can be detected separately by monitoring the life signal periodically output from the light source 30. Therefore, the anomaly information may only indicate that there is a possibility of an anomaly in the CW optical path. Upon confirming the possibility of an anomaly via the interface 70, the user takes action to address the anomaly. Afterward, the user instructs the system to repeat the inspection process by operating the user interface.

[0037] If the light intensity is above the threshold and normal (step S13; Yes), the processor 62 controls the optical switch 40 to connect the first signal line L11 and the second signal line L12 of the main signal line L10 (step S16). The processor 62 controls the light source 30 to high power mode and performs the packet forwarding process to start (step S17). The start process includes the processor 62 instructing the module controller 59 to start the packet forwarding process. Upon receiving this instruction, the module controller 59 starts the signal processing circuit 54, the packet transmission circuit, etc. The start process may also include the process of starting the processor 90. In step S17, CW light with a light intensity stronger than the CW light intensity in low power mode is emitted from the light source 30, and the packet forwarding process, which is the original operation of the signal processing device 10, begins.

[0038] As described above, the signal processing device 10 includes a connector 21, connectors 22A to 22D, a module 50, a main signal line L10, and a sub-signal line L20.

[0039] Connector 21 has a shape that allows it to be optically connected to a light source 30 that emits CW light, which is an optical signal. Connectors 22A to 22D have a shape that allows them to be optically connected to external devices EDa to EDd that constitute the optical network outside the signal processing device 10. Module 50 is a CPO module and is optically connected to connectors 21 and 22A to 22D. Note that the optical connection of the two elements as described above includes not only direct connection of the two elements via an optical waveguide without other optical elements such as optical switches, but also connection via other optical elements.

[0040] The main signal line L10 extends from connector 21 through module 50 to connectors 22A to 22D, transmitting CW light. The sub-signal line L20 branches off from the main signal line L10. The main signal line L10 is positioned between the first signal line L11 and the second signal line L12, and includes an optical switch 40 that switches the optical connection destination of the first signal line L11 between the second signal line L12 and the sub-signal line L20.

[0041] With this configuration, the optical switch 40 can switch the transmission destination of the CW light from the light source 30 between the second signal line L12 (in this case, module 50) and the sub-signal line L20, and the CW light transmitted by the main signal line L10 can be extracted from the middle of the main signal line L10 to the sub-signal line L20.

[0042] Furthermore, as described above, the signal processing device 10 further includes a processing unit 60 connected to the sub-signal line L20. The processing unit 60 performs a first process to detect the signal state (in this case, light intensity) of the CW light from the sub-signal line L20, and a second process based on the detected signal state. This configuration makes it possible to perform processing according to the signal state of the CW light extracted by the optical switch 40. The second process includes an inspection to determine whether the signal state is normal or abnormal. The signal state may be information such as reception quality or whether the light intensity exceeds a threshold. These signal states may be detected by a detector 61 including a comparator circuit or the like.

[0043] Furthermore, as described above, the processing unit 60 performs a second process to stop the operation of the light source 30 when the signal state of the CW light is abnormal and does not meet predetermined conditions (in this case, when the light intensity is lower than a threshold). This configuration prevents the light source 30 from emitting CW light when it is not operating normally. Also, the light intensity of CW light is generally strong. This is because CW light may be distributed by a splitter for use in multiple modulators and / or multiple modules, for example. If there is an abnormality in the path of this CW light, the CW light may unintentionally strike other elements and destroy them, or the CW light may leak outside the signal processing unit 10 and harm people in the vicinity, but stopping the operation reduces this possibility.

[0044] Furthermore, as described above, as the second process, the processing unit 60 performs a process of notifying a user of abnormality information indicating that an abnormality may have occurred in at least one of the light source 30 and the path of the CW light when the signal state of the CW light is an abnormality that does not satisfy a predetermined condition. As an example, the processing unit 60 may be configured to notify abnormality information indicating that an abnormality may have occurred in the light source 30. The processing unit 60 may be configured to notify abnormality information indicating that an abnormality may have occurred in the path of the CW light. The processing unit 60 may be configured to notify abnormality information indicating that an abnormality may have occurred in both the light source 30 and the path of the CW light.

[0045] Furthermore, as described above, the light source 30 included in the signal processing device 10 emits CW light to the outside of the housing 11, and the connector 21 and the light source 30 are optically connected by an optical fiber cable that is the optical waveguide L1 outside the housing 11. The abnormality information includes a message prompting inspection of the optical fiber cable. This can prompt the user to inspect the optical fiber cable (optical waveguide L1) where abnormalities such as connector disconnection are likely to occur, and facilitates the user to detect the abnormality. Note that the optical waveguide L1 is not a component of the signal processing device 10, and may be externally attached to the signal processing device 10. In this case, the outside of the housing 11 can be said to be the outside of the signal processing device 10.

[0046] Furthermore, as described above, the processing unit 60 includes a detector 61 that performs a first process of detecting the signal state of the CW light by converting the CW light into an electrical signal, and a processor 62 that performs the second process. The detector 61 may be configured, for example, from a photoelectric conversion circuit including a light source conversion element, and an electric circuit that performs necessary processing on the electrical signal converted into an electrical signal by the photoelectric conversion element and outputs the processed electrical signal to the processor 62. The processing unit 60 is realized with a simple configuration by the detector 61 and the processor 62.

[0047] Furthermore, as described above, the module 50 modulates input CW light from the connector 21 and outputs the modulated light to the connector 22. When performing the first process, the processing unit 60 performs a third process of controlling the light source 30 to set the light intensity of the CW light to a first intensity (control in a low power mode). Furthermore, as the second process, the processing unit 60 performs processing of controlling the optical switch 40 to connect the first signal line L11 and the second signal line L12 when the signal state of the CW light is normal satisfying a predetermined condition, and controlling the light source 30 to set the light intensity of the CW light to a second intensity higher than the first intensity (control in a high power mode). With this configuration, the light intensity of the CW light can be lowered at a stage where it is unclear whether the signal state of the CW light is normal satisfying the predetermined condition. The CW light from the light source 30 generally has high light intensity as described above. If there is an abnormality in the path of the CW light, there is a possibility that the CW light may unintentionally enter another element and destroy the other element, or the CW light may leak to the outside of the signal processing device 10 and hit surrounding people to cause harm. In this embodiment, until it is confirmed that the signal state of the CW light is normal satisfying the predetermined condition, the light intensity of the CW light is kept low, so that damage to other elements and harm to people are suppressed. Thereby, the safety of the signal processing device 10 is ensured. Note that harm to people is a particular concern when the optical waveguide L1 connecting the light source 30 and the connector 21 is arranged outside the housing 11. This is because if there is an abnormality such as a disconnected connector in the optical waveguide L1, the CW light may hit a person.

[0048] Furthermore, as described above, the signal processing device 10 further includes a processor 90 that performs processing for transferring packets. The module 50 receives an electrical signal indicating a packet transferred by the processor 90, modulates an optical signal based on the input electrical signal to convert the electrical signal into an optical signal indicating the packet, and outputs the optical signal indicating the converted packet to the connector 22. Thereby, the signal processing device 10 can be used as a network switch.

[0049] Furthermore, as described above, the optical switch 40 is positioned between the connector 21 and the module 50, allowing for the extraction of CW light before insertion into the module 50. Additionally, the number of optical switches can be reduced compared to the modified configuration described later. This reduces the number of components, resulting in cost advantages.

[0050] (Modifications) Various modifications are possible to the configuration of the above embodiment. Examples of modifications are given below. Among the elements shown in each figure referenced in the modifications, elements that are the same as or corresponding to the elements in Figure 1 are denoted by the same reference numerals as in Figure 1, and redundant explanations are omitted.

[0051] (Modification 1) The signal processing device 110 according to this modification, shown in Figure 3, has a module 150. In this modification, the optical switch 40 is located inside the module 150. That is, the module 150 is a CPO module packaged with the optical switch 40 included. The optical switch 40 is mounted on a substrate 51. The module 150 includes an optical waveguide 155A that optically connects the optical switch 40 to the optical waveguide L2, an optical waveguide 155B that optically connects the optical switch 40 to the splitter 52, and an optical waveguide 155C that optically connects the optical switch 40 to the optical waveguide L5. The other configurations of the module 150 are the same as those of the module 50. The optical waveguides 155A to 155C are formed directly on the substrate 51, for example, as slab waveguides, but they may be made of optical fiber cables or the like. This also applies to each optical waveguide within the module (the same applies to the above embodiment). In this modified example, optical waveguides L2 and L4, optical switch 40, elements 52 and 53, and optical waveguides 155A, 155B, 56, and 57 constitute the main signal line L10. The first signal line L11 is composed of optical waveguides L2 and 155A. The second signal line L12 is composed of optical waveguide L4, elements 52 and 53, and optical waveguides 155B, 56, and 57. The sub-signal line L20 is composed of optical waveguides L5 and 155B. Further details of the signal processing device 110 are as described in the above embodiment.

[0052] In this modified example, the optical switch 40 is positioned upstream of the splitter 52, which distributes CW light to a plurality of optical modulators 53A to 53D arranged in parallel on the main signal line L10. Therefore, the CW light that is the target of normal / abnormal signal state determination is input to the processing unit 60 before optical distribution at the splitter 52. As a result, even if the light intensity of the CW light is low due to control in low power mode, the CW light is input to the processing unit 60 without being distributed or otherwise processed. Therefore, the light intensity of the CW light reaching the processing unit 60 is maintained to a certain extent, so the second processing based on the signal state of the CW light is performed with high accuracy. Furthermore, the normal / abnormal signal state is also determined with high accuracy. In addition, since the optical switch 40 is built into the module 150, the effort required for assembly is reduced compared to when they are made separately and connected to each other. Also, since the processing of the processing unit 60 is completed within the CPO module, the processing unit 60 may also be packaged within the module 150 (see the dashed line in Figure 3 to enlarge the area of ​​module 150).

[0053] (Modification 3) The signal processing device 210 according to this modification, shown in Figure 4, has optical switches 240A to 240D (collectively referred to as "240") instead of optical switch 40. Each optical switch 240 has the same configuration as optical switch 40, so a detailed explanation is omitted. Connector 21 is optically connected to module 50 via optical waveguide L2. Optical waveguides L4A to L4D connected to module 50 are optically connected to optical switches 240A to 240D, respectively. Optical switches 240A to 240D are optically connected to connectors 22A to 22D, respectively, via optical waveguides L6A to L6D (collectively referred to as "L6"). Optical switches 240A to 240D are connected to receivers 264A to 264D (collectively referred to as "264") of processing unit 260 via optical waveguides L5A to L5D (collectively referred to as "L5"). The optical waveguides L5 and 6D may be waveguides provided on a substrate (for example, slab waveguides) or optical fibers.

[0054] The main signal line L10 of the signal processing device 210 consists of an optical waveguide L2, a splitter 52, an optical modulator 53, optical waveguides 55-57, optical waveguides L4 and L6, and an optical switch 240. The first signal line L11 consists of an optical waveguide L2, a splitter 52, an optical modulator 53, optical waveguides 55-57, and optical waveguide L4. The second signal line L12 consists of an optical waveguide L6. The sub-signal line L20 consists of an optical waveguide L5.

[0055] The processor 62 of the processing unit 260 individually controls the optical switches 240A to 240D. The optical switch 240 switches the connection destination of the optical waveguide L4 (first signal line L11) connected to it to the optical waveguide L5 (sub-signal line) and optical waveguide L6 (second signal line L12), which are also connected to it.

[0056] The processing unit 260 includes a receiver 264 as described above. The receiver 264 photoelectrically converts the CW light from the optical switch 240 connected to it to detect a signal state (e.g., light intensity) and inputs the detected signal state to the processor 62. The receiver 264 may include, as a photoelectric conversion circuit, a photoelectric conversion element such as a photodiode, a TIA, and an A / D conversion circuit, similar to the photoelectric conversion circuit 61B. A VOA may also be provided.

[0057] The processor 62 executes, for example, the inspection process shown in Figure 5. For steps in the inspection process in Figure 5 that are the same as those in the inspection process in Figure 2, the same step numbers are used, and redundant explanations are omitted.

[0058] In the inspection process shown in Figure 5, the processor 62 first performs the process in step S11. In step S11, each of the optical switches 240A to 240D is controlled. In step S11, the CW light from the light source 30 distributed by the splitter 52 is input from the optical switches 240A to 240D to each of the receivers 264A to 264D (elements with the same alphabet are connected). The processor 62 stores each signal state (light intensity) that has been photoelectrically converted in each of the receivers 264A to 264D for each receiver 264 (step S12A). Here, each signal state is registered in the signal state table shown in Figure 6, which is provided in the memory 63. As shown in Figure 6, the signal state is registered in association with a switch ID that identifies the optical switch 240 through which the CW light passed. Note that the switch ID in Figure 6 is the code of the optical switch.

[0059] At the start of the inspection process, the module controller 59 is activated under instructions from the processor 62, and operates the signal processing circuit 54 and other components to operate each of the optical modulators 53A to 53D. Each of the optical modulators 53A to 53D, under the control of the signal processing circuit 54, modulates the CW light from the splitter 52 by adding the switch ID of the optical switch 240 (elements with the same alphabet are connected) that is connected to it. As a result, the receivers 264A to 264D detect the signal state as well as the switch ID based on the CW light and input the signal state and switch ID to the processor 62. The processor 62 registers the input signal state and switch ID in the signal state table. The processor 62 may also identify the switch ID based on which receiver 264 is the source of the signal state input and store the signal state and switch ID in the signal state table. In this way, the signal states input to each of the receivers 264A to 264D are held in the memory 63.

[0060] Subsequently, the processor 62 refers to the signal status table and determines whether all signal statuses registered in the signal status table are normal (i.e., whether the light intensity exceeds the threshold) (step S13A). If at least one of the signal statuses is not normal (step S13A; No), the processor 62 performs the processing in steps S14 and S15A. In this case, if all signal statuses are not normal, there is a high probability that the CW optical path upstream of the splitter 52 (especially the optical waveguide L1 or L2) is abnormal. In such a case, in step S15A, the processor 62 performs the processing to notify the user of an abnormality information (for example, "Please check the optical fiber cable") indicating that there is a high probability that the CW optical path upstream of the splitter 52 is abnormal. On the other hand, if only a portion of the signal state is abnormal, an abnormality may have occurred in the optical path downstream of the splitter 52 through which the CW light of the abnormal signal state was transmitted (for example, if the switch ID of the abnormal signal state is "240A", then optical waveguides L4A, 56A, 57A, etc.). In step S15A, the processor 62 performs a process to inform the user of a second abnormality information (for example, "Please check the path of...") indicating that an abnormality may have occurred in this optical path. Further details of steps S14 and S15A are the same as the descriptions of steps S14 and S15A in the above embodiment.

[0061] If all signal conditions are normal (step S13A; Yes), the processor 62 executes steps S16A and S17. In step S16A, the processing in step S16 is performed for each of the optical switches 240A to 240D.

[0062] As described above, module 50 is provided in the middle of the main signal line L10 and includes an optical modulator 53A that modulates the optical signal and outputs the modulated optical signal to a connector 22A, etc., and the optical switch 240A is positioned between the optical modulator 53A and the connector 22A. As a result, the extracted CW light becomes an optical signal that has passed through module 50, so for example, when inspecting the CW light signal line to check for abnormalities in the signal state, it becomes possible to inspect the signal line (optical waveguide) inside module 50.

[0063] Furthermore, since the optical switches 240A, etc. are positioned between the module 50 and the connector 22A, etc., the optical switches can be added later, for example, after the module has been designed. As shown by the dashed line in Figure 4, the module 50 may be packaged with the optical switches 240A to 240D. The optical switches 240A to 240D are mounted on the circuit board 51. In this case, since the optical switches are built into the module 50, the effort required for assembly is reduced compared to when they are made separately and connected to each other. The processing of the processing unit 260 is also completed within the CPO module, so the processing unit 260 may also be packaged within the module 50 (see also the dashed line in Figure 3).

[0064] Furthermore, module 50 includes multiple optical modulators 53A to 53D, which are provided in parallel in the middle of the main signal line L10 to modulate CW light and output the modulated CW light to multiple connectors 22A to 22D, respectively, and a splitter 52 that distributes the CW light to each of the multiple optical modulators 53A to 53D. Multiple optical switches 240A to 240D are arranged between the multiple connectors 22A to 22D and the multiple optical modulators 53A to 53D, respectively. The sub-signal line L20 includes multiple optical waveguides L5A to L5D connected to each of the multiple optical switches 240A to 240D. Processing unit 60 performs a first process in which receivers 264A to 264D detect the signal state of the CW light from each of the multiple optical waveguides L5A to L5D, and a second process in which processor 62 performs the signal state. The second process includes notifying the user of a first anomaly information indicating that an anomaly may have occurred in the CW light path upstream of the splitter 52 (i.e., the signal line through which the CW light was transmitted) when all of the detected signal states do not meet predetermined conditions. The second process also includes notifying the user of a second anomaly information indicating that an anomaly may have occurred in the signal line downstream of the splitter 52 through which the CW light of the anomaly signal state was transmitted, when only some of the detected signal states do not meet predetermined conditions (a partial anomaly). With this configuration, it becomes possible to determine the location of the anomaly based on which of the multiple signal states is anomaly.

[0065] (Modification 4) The optical waveguide L1 may be located inside the housing 11 instead of outside it. In this case, the light source 30 and the connector 21 may be located inside the housing 11 of the signal processing device 10. The hardware configuration of each element described above is arbitrary. The light source 30 only needs to emit an optical signal, and may emit an optical signal other than CW light. The signal processing device 10 may be configured as a device other than a network switch. The signal processing device 10 may be configured as a device that processes the optical signal from the light source by modulation or the like. The processor 90 may be configured as a device that performs processing other than packet forwarding. For example, the processor 90 may perform predetermined processing and output the processing result data to the CPO module, and the CPO module may convert the processing result data, i.e., the electrical signal, into an optical signal by modulating the optical signal from the light source based on the processing result data. The program 63P may be stored in a computer-readable non-temporary storage medium such as a storage device. The number of each of the above elements, such as the number of connectors 22, can be changed arbitrarily.

[0066] (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.

[0067] (Note) The following are examples of configurations that use the above embodiments and modified examples as one example. Any part of the above embodiments and modified examples may be applied to each note. Also, parts of each note may be combined. (Note 1) A signal processing device comprising: a first connector configured to be optically connected to a light source that emits an optical signal; a second connector configured to be optically connected to an external device of the signal processing device; a CPO (Co-packaged Optical) module optically connected to the first connector and the second connector; a main signal line extending from the first connector through the CPO module to the second connector to transmit the optical signal, the main signal line including a first signal line connected to the first connector and a second signal line connected to the second connector; and a sub-signal line branching from the main signal line, wherein the main signal line includes an optical switch positioned between the first signal line and the second signal line to switch the optical connection destination of the first signal line between the second signal line and the sub-signal line. (Note 2) The signal processing device according to Note 1, further comprising a processing unit connected to the sub-signal line, wherein the processing unit performs a first process for detecting the signal state of the optical signal from the sub-signal line, and a second process based on the detected signal state. (Note 3) The signal processing device according to Note 2, wherein the processing unit performs, as the second process, a process for stopping the operation of the light source when the signal state is abnormal and does not meet predetermined conditions. (Note 4) The signal processing device according to Note 2 or 3, wherein the processing unit performs, as the second process, a process for notifying the user of abnormal information indicating that an abnormality may have occurred in at least one of the light source and the signal line through which the optical signal was transmitted when the signal state is abnormal and does not meet predetermined conditions. (Note 5) The signal processing device according to Note 4, further comprising the light source, wherein the light source emits the optical signal to the outside of the signal processing device, the first connector and the light source are optically connected by an optical fiber cable outside the signal processing device, and the abnormal information includes a message prompting inspection of the optical fiber cable.(Note 6) The signal processing apparatus according to any one of Notes 1 to 5, wherein the processing unit comprises a detector that performs a first processing to detect the signal state by converting the optical signal into an electrical signal, and a processor that performs a second processing. (Note 7) The signal processing apparatus according to any one of Notes 2 to 6, wherein the CPO module modulates the optical signal from the first connector and outputs it to the second connector, and the processing unit, when performing the first processing, performs a third processing to control the light source to set the light intensity of the optical signal to a first intensity, and as a second processing, when the signal state is normal and satisfies predetermined conditions, controls the optical switch to connect the first signal line and the second signal line, and performs a processing to control the light source to set the light intensity of the optical signal to a second intensity which is stronger than the first intensity. (Note 8) The signal processing apparatus according to Note 7, wherein the first connector is formed in a shape that is optically connected to the light source by an optical fiber cable located outside the signal processing apparatus. (Note 9) The signal processing device according to any one of Notes 1 to 8, further comprising a processor that performs packet forwarding processing, wherein the CPO module receives an electrical signal indicating the packet to be forwarded by the processor, modulates the optical signal based on the input electrical signal to convert the electrical signal into an optical signal indicating the packet, and outputs the converted optical signal indicating the packet to the second connector. (Note 10) The signal processing device according to any one of Notes 1 to 9, wherein the optical switch is located between the first connector and the CPO module. (Note 11) The signal processing device according to any one of Notes 1 to 10, wherein the CPO module comprises a modulator provided in the middle of the main signal line to modulate the optical signal, and an optical switch located upstream of the modulator. (Note 12) The signal processing apparatus according to Notes 1 to 11, wherein the CPO module comprises a plurality of modulators arranged in parallel in the middle of the main signal line for modulating the optical signal, a splitter for distributing the optical signal to each of the plurality of modulators, and the optical switch arranged before the splitter.(Note 13) The signal processing device according to any one of Notes 1 to 12, wherein the CPO module is provided in the middle of the main signal line and includes a modulator that modulates the optical signal and outputs the modulated optical signal to the second connector, and the optical switch is located between the modulator and the second connector. (Note 14) The signal processing device according to Note 13, wherein the optical switch is located between the CPO module and the second connector. (Note 15) The signal processing device according to Note 13, wherein the CPO module includes the optical switch. (Note 16) The signal processing device according to any one of Notes 1 to 15, wherein the second connector includes a plurality of second connectors, the CPO module includes a plurality of modulators provided in parallel in the middle of the main signal line to modulate the optical signal and output the modulated optical signal to the plurality of second connectors, and a splitter to distribute the optical signal to each of the plurality of modulators, the optical switch includes a plurality of optical switches arranged between the plurality of second connectors and the plurality of modulators, and the sub-signal line includes the plurality of optical waveguides connected to each of the plurality of optical switches. (Note 17) The signal processing device according to Note 16, further comprising a processing unit connected to the plurality of optical waveguides, wherein the processing unit performs: a first process for detecting the signal state of the optical signals from each of the plurality of optical waveguides; and a second process based on the detected signal state, the second process including: a process for notifying the user of first abnormality information indicating that an abnormality may have occurred in the signal line to which the optical signal was transmitted upstream of the splitter when all of the detected signal states do not satisfy predetermined conditions; and a process for notifying the user of second abnormality information indicating that an abnormality may have occurred in the signal line to which the optical signal of the abnormal signal state was transmitted downstream of the splitter when only a portion of the detected signal states do not satisfy predetermined conditions.

[0068] 10...Signal processing unit, 11...Housing, 21...Connector, 22...Connector, 22A-22D...Connector, 30...Light source, 40...Optical switch, 50...Module, 51...Circuit board, 52...Splitter, 53...Optical modulator, 53A-53D...Optical modulator, 54...Signal processing circuit, 55-57...Optical waveguide, 56A-56D...Optical waveguide, 57A-57D...Optical waveguide, 59...Module controller, 60...Processing unit, 61...Detector, 61A...Variable optical attenuator, 61B...Photoelectric conversion circuit, 62...Processor, 63...Memory, 63P...Program, 70 ...Interface, 90...Processor, 91A-91D...Port, 110...Signal processing unit, 150...Module, 155A-155C...Optical waveguide, 210...Signal processing unit, 240, 240A-240D...Optical switch, 260...Processing unit, 264, 264A-264D...Receiver, EDa-EDd...External device, L1-L6...Optical waveguide, L4A-L4D...Optical waveguide, L5A-L5D...Optical waveguide, L6A-L6D...Optical waveguide, L10...Main signal line, L11...First signal line, L12...Second signal line, L20...Sub-signal line.

Claims

1. A signal processing device comprising: a first connector configured to be optically connected to a light source that emits an optical signal; a second connector configured to be optically connected to an external device of the signal processing device; a CPO (Co-packaged Optical) module optically connected to the first connector and the second connector; a main signal line extending from the first connector through the CPO module to the second connector to transmit the optical signal, the main signal line including a first signal line connected to the first connector and a second signal line connected to the second connector; and a sub-signal line branching from the main signal line, wherein the main signal line includes an optical switch positioned between the first signal line and the second signal line, which switches the optical connection destination of the first signal line between the second signal line and the sub-signal line.

2. The signal processing apparatus according to claim 1, further comprising a processing unit connected to the sub-signal line, wherein the processing unit performs a first process for detecting the signal state of the optical signal from the sub-signal line, and a second process based on the detected signal state.

3. The signal processing apparatus according to claim 2, wherein the processing unit performs a second process, which involves stopping the operation of the light source when the signal state is abnormal and does not meet predetermined conditions.

4. The signal processing apparatus according to claim 2, wherein the processing unit performs a second process of notifying the user of an abnormality information indicating that an abnormality may have occurred in at least one of the light source and the signal line through which the optical signal was transmitted when the signal state is abnormal and does not meet predetermined conditions.

5. The signal processing apparatus according to claim 4, further comprising the light source, wherein the light source emits the optical signal outside the signal processing apparatus, the first connector and the light source are optically connected by an optical fiber cable outside the signal processing apparatus, and the abnormal information includes a message prompting inspection of the optical fiber cable.

6. The signal processing apparatus according to claim 2, wherein the CPO module modulates the optical signal from the first connector and outputs it to the second connector, the processing unit performs a third process in which, when performing the first process, controls the light source to set the light intensity of the optical signal to a first intensity, and as a second process, when the signal state is normal and satisfies predetermined conditions, controls the optical switch to connect the first signal line and the second signal line, and controls the light source to set the light intensity of the optical signal to a second intensity which is stronger than the first intensity.

7. The signal processing apparatus according to claim 1, further comprising a processor that performs packet forwarding processing, wherein the CPO module receives an electrical signal indicating the packet to be forwarded by the processor, modulates the optical signal based on the input electrical signal to convert the electrical signal into an optical signal indicating the packet, and outputs the converted optical signal indicating the packet to the second connector.

8. The signal processing apparatus according to claim 1, wherein the optical switch is located between the first connector and the CPO module.

9. The signal processing apparatus according to claim 1, wherein the CPO module comprises a modulator provided in the middle of the main signal line for modulating the optical signal, and an optical switch positioned before the modulator.

10. The signal processing apparatus according to claim 1, wherein the CPO module comprises a plurality of modulators arranged in parallel in the middle of the main signal line for modulating the optical signal, a splitter for distributing the optical signal to each of the plurality of modulators, and the optical switch arranged before the splitter.

11. The signal processing apparatus according to claim 1, wherein the CPO module is provided in the middle of the main signal line and includes a modulator that modulates the optical signal and outputs the modulated optical signal to the second connector, and the optical switch is positioned between the modulator and the second connector.

12. The signal processing apparatus according to claim 1, wherein the second connector includes a plurality of second connectors, the CPO module includes a plurality of modulators provided in parallel in the middle of the main signal line to modulate the optical signal and output the modulated optical signal to the plurality of second connectors, respectively, and a splitter to distribute the optical signal to each of the plurality of modulators, the optical switch includes a plurality of optical switches arranged between the plurality of second connectors and the plurality of modulators, respectively, and the sub-signal line includes the plurality of optical waveguides connected to each of the plurality of optical switches.

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