JP2014082592A - Optical module for optical communication system and method of updating firmware of optical module for optical communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical module for an optical communication system that allows avoiding an unexpected operation of an optical device in updating the firmware of an arithmetic processing circuit.SOLUTION: An optical module 1A comprises: an optical device 10 driven by a driving voltage Vd; an arithmetic processing chip 20 including an arithmetic processing circuit 21 that operates according to a predetermined firmware and generates an electrical control signal Sd indicating the magnitude of the driving voltage Vd; a voltage generating unit 30 having an input terminal 31 receiving the control signal Sd from the arithmetic processing chip 20 and an output terminal 32 providing the driving voltage Vd having the magnitude according to the control signal Sd for the optical device 10, the voltage generating unit 30 being provided outside the arithmetic processing chip 20; and a voltage holding unit 40 for holding an output voltage from the output terminal 32 of the voltage generating unit 30 to a constant voltage regardless of the operation state of the arithmetic processing circuit 21 in updating the firmware.

Description

  The present invention relates to an optical module for an optical communication system and a method for updating firmware of the optical module for an optical communication system.

  Patent Document 1 describes a wavelength selective switch that separates signal light including a plurality of signal components having different wavelengths from each other and outputs the separated signal components from different output ports. This wavelength selective switch includes a MEMS (Micro Electro Mechanical System) mirror that switches the reflection direction for each signal component, and a control unit that applies a drive voltage to the MEMS mirror. The control unit includes a firmware storage unit that stores a predetermined program, a CPU (Central Processing Unit) that operates by loading the program from the firmware storage unit, and a digital-analog that receives the control signal from the CPU and generates the drive voltage And a converter.

JP 2009-175614 A

  For example, an optical module including an optical device such as a MEMS mirror driven by electric power, such as the wavelength selective switch described above, may be used in an optical communication system. Another example of an optical module including such an optical device is, for example, an optical amplifier including a rare earth-doped optical fiber for amplifying signal light and a pumping light source that supplies pumping light to the rare earth-doped optical fiber. is there. In this optical amplifier, the excitation light source is driven by electric power.

  In many cases, such an optical module is provided from an arithmetic processing circuit such as a CPU that generates an electric signal indicating the magnitude of electric power applied to an optical device, typically the magnitude of a voltage, and the arithmetic processing circuit. And a voltage generator that generates a drive voltage having a magnitude corresponding to the electrical signal. The arithmetic processing circuit operates according to predetermined firmware such as a software program.

  The firmware of the arithmetic processing circuit is updated as necessary. However, normally, when updating the firmware, the arithmetic processing circuit is once reset and restarted. In the conventional optical module, when such an arithmetic processing circuit is restarted, the electric signal provided to the voltage generation unit becomes indefinite. At this time, if noise is superimposed on the electrical signal, the drive voltage output from the voltage generator varies, and the optical device may perform unexpected operations. In the optical communication system, it is desirable that the communication state be maintained even when the firmware is updated, and it is desirable to avoid the unexpected operation of the optical device as described above.

  The present invention has been made in view of such problems, and an optical module for an optical communication system capable of avoiding an unexpected operation of an optical device when updating firmware of an arithmetic processing circuit, and an optical An object of the present invention is to provide a method for updating firmware of an optical module for a communication system.

  In order to solve the above-described problems, an optical module for an optical communication system according to the present invention operates in accordance with an optical device driven by a driving voltage and predetermined firmware, and receives an electrical control signal indicating the magnitude of the driving voltage. An arithmetic processing chip including an arithmetic processing circuit to be generated; an input terminal that receives a control signal from the arithmetic processing chip; and an output terminal that provides a drive voltage having a magnitude corresponding to the control signal to the optical device. A voltage generation unit provided outside and a voltage holding unit that sets the output voltage from the output terminal of the voltage generation unit to a constant voltage regardless of the operation state of the arithmetic processing circuit when updating the firmware, To do.

  In the optical module for an optical communication system, a control signal indicating a drive voltage value to the optical device calculated in the arithmetic processing circuit is provided from the arithmetic processing circuit to the voltage generation unit. The voltage generator generates a drive voltage having a magnitude indicated by the control signal and provides the drive voltage to the optical device.

  As described above, when the firmware of the arithmetic processing circuit is updated, the arithmetic processing circuit is once reset and restarted. In the conventional optical module, when such an arithmetic processing circuit is restarted, the control signal provided to the voltage generation unit becomes indefinite, and when noise is superimposed on the control signal at this time, the voltage generation unit outputs the control signal. The drive voltage may fluctuate and the optical device may perform unexpected operations. On the other hand, in the optical module for an optical communication system, when the firmware is updated, the voltage holding unit sets the output voltage from the output terminal of the voltage generation unit to a constant voltage regardless of the operation state of the arithmetic processing circuit. . Therefore, when the firmware is updated, unexpected operation of the optical device can be avoided and a good communication state can be maintained.

  In general, when the arithmetic processing circuit is reset and restarted, the entire arithmetic processing chip including the arithmetic processing circuit is reset and restarted. Therefore, when the voltage generation unit is included in the arithmetic processing chip, the drive voltage output from the voltage generation unit is reset and restarted, which affects the operation of the optical device. On the other hand, in the above optical module for an optical communication system, the voltage generation unit is provided outside the arithmetic processing chip, so that the voltage generation is performed even when the entire arithmetic processing chip is reset and restarted. The part can continue to operate. Therefore, unexpected operation of the optical device can be avoided and a good communication state can be maintained.

  Further, in the optical module for an optical communication system, the voltage generation unit further includes a chip selector input terminal for inputting a chip selector signal, and outputs a driving voltage having a magnitude corresponding to the control signal based on the chip selector signal. The voltage output may be switched, and the voltage holding unit may generate a chip selector signal so that the voltage generation unit outputs a constant voltage when updating the firmware. As a result, when updating the firmware, the output voltage from the output terminal of the voltage generator can be made constant regardless of the operation state of the arithmetic processing circuit.

  Further, in the optical module for an optical communication system, the voltage holding unit is connected between the arithmetic processing chip and the input terminal of the voltage generation unit, and a control signal indicating the magnitude of the drive voltage at the time of firmware update Instead of this, a control signal indicating a constant voltage may be provided to the input terminal of the voltage generator. As a result, when updating the firmware, the output voltage from the output terminal of the voltage generator can be made constant regardless of the operation state of the arithmetic processing circuit.

  The optical module for an optical communication system may be characterized in that the constant voltage is equal to the driving voltage immediately before the firmware update. Thereby, operation | movement of an optical device can be continued suitably and a favorable communication state can be maintained.

  In the optical module for an optical communication system, the firmware may include a software program, and the arithmetic processing circuit may include a CPU that operates by reading the software program from a memory storing the software program. Alternatively, in the optical module for an optical communication system, the arithmetic processing circuit may include rewritable hardware capable of rewriting an internal circuit represented by firmware.

  In the optical module for an optical communication system, the optical device may be an optical deflecting element for a wavelength selective switch. Alternatively, the optical module for an optical communication system may be an excitation light source in which an optical device supplies excitation light to an optical amplification unit for amplification of signal light. Alternatively, the optical module for an optical communication system is a variable optical attenuator in which an optical device is optically coupled between a first optical amplifying unit and a second optical amplifying unit for amplifying signal light. May be.

  The method for updating the firmware of the optical module for an optical communication system according to the present invention operates according to predetermined firmware and generates an electrical control signal indicating the magnitude of the drive voltage to the optical device driven by the drive voltage. An optical processing system including an arithmetic processing chip including an arithmetic processing circuit and a voltage generator provided outside the arithmetic processing chip and providing a drive voltage having a magnitude corresponding to a control signal to an optical device. A method for updating firmware in a module, in which a first step of storing and storing setting information immediately before updating the firmware, with the output voltage from the output terminal of the voltage generation unit being a constant voltage, and rewriting the firmware 2 steps and reset the arithmetic processing circuit to upgrade the firmware Characterized in that it comprises a third step to continue the operation by restoring the configuration information over bets immediately before.

  In this update method, when the firmware is updated, the output voltage from the output terminal of the voltage generation unit is set to a constant voltage, so that an unexpected operation of the optical device can be avoided and a good communication state can be maintained. In addition, since the voltage generation unit is provided outside the arithmetic processing chip, the voltage generation unit can continue to operate even when the entire arithmetic processing chip is reset and restarted. Therefore, unexpected operation of the optical device can be avoided and a good communication state can be maintained.

  According to the optical module for an optical communication system and the method for updating the firmware of the optical module for an optical communication system according to the present invention, it is possible to avoid an unexpected operation of the optical device when updating the firmware of the arithmetic processing chip.

FIG. 1 is a block diagram schematically showing the configuration of the optical module according to the first embodiment. FIG. 2 is a flowchart showing a method for updating the firmware of the optical module. FIG. 3 is a diagram illustrating a configuration of a specific example of the optical module. FIG. 4 is a diagram illustrating a configuration of an optical module according to the second embodiment.

  Hereinafter, embodiments of an optical module for an optical communication system and a method for updating firmware of the optical module for an optical communication system according to the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted.

(First embodiment)
FIG. 1 is a block diagram schematically showing the configuration of an optical module 1A according to the first embodiment of the present invention. The optical module 1A of the present embodiment is an optical module used for optical communication, and is a device such as a wavelength selective switch or an optical amplifier, for example. As shown in FIG. 1, the optical module 1 </ b> A includes an optical device 10, an arithmetic processing chip 20 including an arithmetic processing circuit 21, a voltage generation unit 30, and a voltage holding unit 40.

  The optical device 10 is an optical device that is driven by the drive voltage Vd. As the optical device 10, pumping light is applied to an optical deflecting element (for example, a MEMS mirror or LCoS (Liquid crystal on silicon)) used for a wavelength selective switch, or a rare earth-doped optical fiber for amplification of signal light. Examples include a pumping light source to be supplied, or a variable optical attenuator optically coupled between two rare earth-doped optical fibers in order to make the loss imparted to the signal light variable.

  The arithmetic processing circuit 21 is a large-scale integrated circuit for generating an electrical control signal Sd indicating the magnitude of the drive voltage Vd, and operates according to predetermined firmware. The arithmetic processing circuit 21 includes, for example, a central processing unit (CPU). When the arithmetic processing circuit 21 includes a CPU, the firmware is composed of a software program. The software program is stored in advance in the memory. The memory is a non-volatile memory and is provided inside or outside the arithmetic processing circuit 21. The CPU of the arithmetic processing circuit 21 operates by reading a software program from the memory. Further, the arithmetic processing circuit 21 performs an operation of storing information set immediately before the update in the memory before updating the firmware. The information stored at this time is, for example, a setting port for each wavelength, a setting voltage set in the DAC, or the like. In the memory, information to be stored may be either a non-volatile memory or a volatile memory having a function that does not disappear even when the CPU is reset. As a volatile memory having a function that does not erase information even if the CPU is reset, for example, there is an SRAM (Static RAM) that does not require a refresh operation periodically.

  The arithmetic processing circuit 21 may be rewritable hardware capable of rewriting an internal circuit represented by firmware. Examples of rewritable hardware include a programmable logic device (PLD), a field programmable gate array (FPGA), and a digital signal processor (DSP). Even when the arithmetic processing circuit 21 is composed of these hardware, the control signal Sd that operates according to predetermined firmware and indicates the magnitude of the drive voltage Vd can be suitably generated.

  The control signal Sd is sent to the voltage generator 30 as digital data. The method of sending the control signal Sd may be either a parallel method or a serial method. When the serial method is used, the control signal Sd is sent to the voltage generation unit 30 using a communication interface such as USART (RS232), SPI, or I2C.

  Whether the arithmetic processing circuit 21 includes a CPU or the arithmetic processing circuit 21 includes rewritable hardware, the firmware is updated as necessary. The update is performed to improve firmware functions and correct defects. When updating the firmware, the arithmetic processing circuit 21 is once reset and restarted.

  The arithmetic processing circuit 21 is built in the arithmetic processing chip 20. The arithmetic processing chip 20 has a package for sealing the arithmetic processing circuit 21 mounted on, for example, a lead frame, and is mounted on a wiring board (not shown). When the arithmetic processing circuit 21 includes a CPU, the arithmetic processing chip 20 may be a so-called microprocessor (MPU; Micro Processing Unit).

  The voltage generation unit 30 provides the optical device 10 with a drive voltage Vd having a magnitude corresponding to the control signal Sd. The voltage generation unit 30 has an input terminal 31 and an output terminal 32. A control signal Sd is input from the arithmetic processing circuit 21 to the input terminal 31. A drive voltage Vd having a magnitude corresponding to the control signal Sd is output from the output terminal 32. The voltage generation unit 30 includes an analog-digital converter, and converts the control signal Sd that is a digital signal provided from the arithmetic processing circuit 21 into a drive voltage Vd that is an analog signal.

  The voltage generator 30 is provided outside the arithmetic processing chip 20. Here, the outside of the arithmetic processing chip 20 means the outside of the package that seals the built-in circuit (the arithmetic processing circuit 21 or the like) of the arithmetic processing chip 20. That is, the voltage generation unit 30 and the arithmetic processing chip 20 are mounted on different regions on a common wiring board and are electrically connected to each other via a wiring pattern formed on the wiring board.

  The voltage holding unit 40 is a circuit part for setting the output voltage from the output terminal 32 of the voltage generating unit 30 to a constant voltage regardless of the operation state of the arithmetic processing circuit 21 when the firmware of the arithmetic processing circuit 21 is updated. is there. For example, the voltage holding unit 40 of the present embodiment is connected between the arithmetic processing chip 20 and the input terminal 31 of the voltage generation unit 30, and controls the magnitude of the drive voltage Vd when updating the firmware. Instead of the signal Sd, a control signal Sd indicating a constant voltage is provided to the input terminal 31 of the voltage generator 30.

  The voltage generation unit 30 further includes a chip selector input terminal 33 for inputting the chip selector signal Scs. Based on the state of the chip selector signal Scs, the output of the drive voltage Vd having a magnitude corresponding to the control signal Sd In some cases, it has a function of switching between output of a constant voltage. In such a case, when updating the firmware, the voltage holding unit 40 is configured so that the voltage generation unit 30 outputs a constant voltage instead of or together with the provision of the control signal Sd indicating the constant voltage described above. The selector signal Scs may be generated and provided to the chip selector input terminal 33 of the voltage generation unit 30.

  Note that it is preferable that the constant voltage output from the voltage generation unit 30 when updating the firmware is equal to the drive voltage Vd immediately before the update.

  FIG. 2 is a flowchart showing a method for updating the firmware of the optical module 1A according to the present embodiment. As shown in FIG. 2, when updating the firmware, the voltage holding unit 40 first sets the output voltage from the output terminal 32 of the voltage generation unit 30 to a constant voltage, and stores the setting information immediately before the firmware update as firmware update information storage. Store and store in the unit (first step S1). Next, the operation of the arithmetic processing circuit 21 is stopped, and the firmware is rewritten (second step S2). Subsequently, the arithmetic processing circuit 21 is reset and restarted, the operation of the arithmetic processing circuit 21 by the firmware after rewriting is started, the information in the firmware update information storage unit is read, and the setting content before the firmware update is restored ( Third step S3). At this time, the voltage holding unit 40 provides the voltage generation unit 30 with a control signal Sd indicating the magnitude of the drive voltage Vd from the arithmetic processing circuit 21.

  FIG. 3 is a diagram illustrating a configuration of an optical module 1B as a specific example of the optical module. The optical module 1B is a wavelength selective switch used in an optical communication system, and includes a MEMS mirror 12 as an optical deflection element as the optical device 10. The optical module 1B also includes one input optical waveguide 51 and a plurality of output optical waveguides 52. The signal light L1 emitted from the input optical waveguide 51 is a light reflecting surface of the MEMS mirror 12. The light is reflected at 12a and selectively enters one of the plurality of output optical waveguides 52 in accordance with the reflection angle. The reflection angle at the light reflecting surface 12a is controlled by two drive voltages (X-axis drive voltage Vd1 and Y-axis drive voltage Vd2) provided from the control unit 15. The lens 13 is disposed between the input optical waveguide 51 and the plurality of output optical waveguides 52 and the MEMS mirror 12.

  The control unit 15 includes the arithmetic processing circuit 21, the voltage generation unit 30, and the voltage holding unit 40 shown in FIG. The arithmetic processing circuit 21 is composed of a large scale integrated circuit such as a CPU or a PLD. A firmware storage unit 22, a drive voltage storage unit 23, and a firmware update information storage unit 24 are electrically connected to the arithmetic processing circuit 21.

  The firmware storage unit 22 is a part that stores firmware for operating the arithmetic processing circuit 21. As described above, the firmware storage unit 22 is composed of, for example, a nonvolatile memory. Further, the firmware storage unit 22 may be accommodated in the arithmetic processing chip 20 incorporating the arithmetic processing circuit 21 or may be provided outside the arithmetic processing chip 20.

  The drive voltage storage unit 23 is a part for storing the magnitude of the drive voltage. The drive voltage storage unit 23 stores, for example, the magnitudes of the X-axis drive voltage Vd1 and the Y-axis drive voltage Vd2 for selectively reflecting the signal light L1 toward the output optical waveguides 52. The arithmetic processing circuit 21 stores, for example, information on appropriate magnitudes of the X-axis drive voltage Vd1 and the Y-axis drive voltage Vd2 based on selection information of the output optical waveguide 52 input from the outside of the optical module 1B. Read from the unit 23, and output control signals Sd1 and Sd2 according to the magnitude.

  The firmware update information storage unit 24 is a part for storing setting information before firmware update. For example, the information that must be continued before and after the firmware update is the attenuation amount of the setting port for each wavelength, the setting drive voltage, and the like. By taking over these pieces of information, the operation can be continued without causing a difference in setting values before and after the update.

  The voltage generation unit 30 includes DA converters 34a and 34b, high voltage amplification units 35a and 35b, and drive units 36a and 36b. The DA converter 34a, the high voltage amplification unit 35a, and the drive unit 36a are circuit parts for generating the X-axis drive voltage Vd1, and the DA converter 34b, the high voltage amplification unit 35b, and the drive unit 36b generate the Y-axis drive voltage Vd2. It is a circuit part for doing.

  The DA converter 34a converts the control signal Sd1 that is a digital signal output from the arithmetic processing circuit 21 into a control signal Sa1 that is an analog signal, and outputs the control signal Sa1 to the high voltage amplifier 35a. The high voltage amplification unit 35a converts the control signal Sa1 into the X-axis drive voltage Vd1, and outputs the X-axis drive voltage Vd1 to the drive unit 36a. The drive unit 36a supplies the X-axis drive voltage Vd1 to the MEMS mirror 12.

  The DA converter 34b converts the control signal Sd2 that is a digital signal output from the arithmetic processing circuit 21 into a control signal Sa2 that is an analog signal, and outputs the control signal Sa2 to the high voltage amplifier 35b. The high voltage amplifier 35b converts the control signal Sa2 into a Y-axis drive voltage Vd2, and outputs this Y-axis drive voltage Vd2 to the drive unit 36b. The drive unit 36b supplies the Y-axis drive voltage Vd2 to the MEMS mirror 12.

  The voltage holding unit 40 includes a communication state holding unit 41. When the firmware of the arithmetic processing circuit 21 is updated, the communication state holding unit 41 sets the output voltage from the voltage generation unit 30 to a constant voltage regardless of the operation state of the arithmetic processing circuit 21. For example, when the firmware is updated, the communication state holding unit 41 according to this embodiment replaces the control signals Sd1 and Sd2 indicating the magnitudes of the drive voltages Vd1 and Vd2 with the control signals Sd1 and Sd2 indicating the constant voltage DA. Provided to converters 34a and 34b.

  Further, the DA converters 34a and 34b of the present embodiment further have a chip selector input terminal for inputting the chip selector signals Scs1 and Scs2, and according to the control signals Sd1 and Sd2 based on the state of the chip selector signals Scs1 and Scs2. A function of switching between the output of the drive voltages Vd1 and Vd2 of a certain magnitude and the output of a constant voltage. Then, the communication state holding unit 41 causes the DA converters 34a and 34b to output a constant voltage instead of or together with the provision of the control signals Sd1 and Sd2 indicating the constant voltage described above when updating the firmware. Chip selector signals Scs1, Scs2 are generated and provided to the chip selector input terminals of the DA converters 34a, 34b.

  According to the optical module 1A, 1B having the above configuration and the firmware update method, the following effects can be obtained. As described above, in the optical communication system, it is desirable that a good communication state be maintained even when the firmware of the arithmetic processing circuit is updated. However, in the conventional optical module, when the firmware is updated, once the arithmetic processing circuit is reset and restarted, the control signal provided to the voltage generation unit becomes indefinite and is output from the voltage generation unit. The drive voltage may fluctuate and the optical device may perform unexpected operations. On the other hand, in the optical modules 1A and 1B of the present embodiment, when the firmware is updated, the output voltage from the output terminal 32 of the voltage generator 30 is changed by the voltage holding unit 40 regardless of the operation state of the arithmetic processing circuit 21. The voltage is constant. Therefore, when firmware is updated, an unexpected operation of the optical device 10 (for example, the MEMS mirror 12) can be avoided and a good communication state can be maintained.

  In general, when the arithmetic processing circuit is reset and restarted, the entire arithmetic processing chip including the arithmetic processing circuit is reset and restarted. Therefore, when the voltage generation unit is included in the arithmetic processing chip, the drive voltage output from the voltage generation unit is reset and restarted, which affects the operation of the optical device. On the other hand, in the optical modules 1A and 1B of the present embodiment, since the voltage generation unit 30 is provided outside the arithmetic processing chip 20, the entire arithmetic processing chip 20 is reset and restarted. However, the voltage generator 30 can continue to operate. Therefore, an unexpected operation of the optical device 10 (for example, the MEMS mirror 12) can be avoided and a good communication state can be maintained.

  Further, as in the present embodiment, the voltage generation unit 30 further includes a chip selector input terminal for inputting the chip selector signal Scs (or Scs1, Scs2), and is controlled based on the chip selector signal Scs (or Scs1, Scs2). When the voltage holding unit 40 has a function of switching between the output of the drive voltage Vd (or Vd1, Vd2) having a magnitude corresponding to the signal Sd (or Sd1, Sd2) and the output of a constant voltage, the voltage holding unit 40 performs the firmware update. The chip selector signal Scs (or Scs1, Scs2) may be generated so that the voltage generator 30 outputs a constant voltage. Thereby, when updating the firmware, the output voltage from the output terminal of the voltage generation unit 30 can be made constant regardless of the operation state of the arithmetic processing circuit 21.

  In addition, as in the present embodiment, the voltage holding unit 40 is connected between the arithmetic processing chip 20 and the input terminal of the voltage generation unit 30, and the drive voltage Vd (or Vd1, Vd2) is used when the firmware is updated. Instead of the control signal Sd indicating the magnitude of (or Sd1, Sd2), a control signal Sd (or Sd1, Sd2) indicating a constant voltage may be provided to the input terminal of the voltage generator 30. Thereby, when updating the firmware, the output voltage from the output terminal of the voltage generation unit 30 can be made constant regardless of the operation state of the arithmetic processing circuit 21.

  Further, as in the present embodiment, it is preferable that the constant voltage output from the voltage generation unit 30 when updating the firmware is equal to the drive voltage Vd (or Vd1, Vd2) immediately before the update. Thereby, the operation | movement of the optical device 10 (for example, MEMS mirror 12) can be continued suitably, and a favorable communication state can be maintained.

(Second Embodiment)
FIG. 4 is a diagram showing a configuration of an optical module 1C according to the second embodiment of the present invention. The optical module 1C of this embodiment is one of the specific examples of the optical module 1A shown in FIG. 1, and is an optical amplifier used in an optical communication system. The optical module 1C shown in FIG. 4 optically amplifies the signal light L2 input to the input terminal 61a and outputs it from the output terminal 61b, and the signal light L2 transmission path from the input terminal 61a to the output terminal 61b In this order, an optical coupler 62, an optical coupler 63, an optical amplifying unit 64, a variable optical attenuator (VOA) 65, an optical coupler 66, an optical amplifying unit 67, and an optical coupler 68 are provided. The variable optical attenuator 65 is a component corresponding to the optical device 10 shown in FIG.

  The optical module 1C includes a light receiving element 71 connected to the optical coupler 62, a light receiving element 72 connected to the optical coupler 68, a pumping light source 73 connected to the optical coupler 63, and a pumping light source connected to the optical coupler 66. 74, a control unit 75 that controls the excitation light sources 73 and 74, and a control unit 76 that controls the variable optical attenuator 65. The excitation light sources 73 and 74 are components corresponding to the optical device 10 shown in FIG.

  The optical coupler 62 inputs the signal light L2 that has been input and arrived at the input terminal 61a, outputs the signal light L2 to the optical coupler 63, and branches a part of the signal light L2 to output it to the light receiving element 71. To do. The optical coupler 63 receives the signal light L2 that is output from the optical coupler 62 and arrives, and also receives the pumping light L3 that is output from the pumping light source 73, and optically amplifies the signal light L2 and the pumping light L3. To the unit 64. The optical amplifying unit 64 receives the signal light L2 and the pumping light L3 that are output from the optical coupler 63, is excited by the pumping light L3, and optically amplifies and outputs the signal light L2. Is a rare earth element-doped optical fiber such as EDF (Erbium Doped Fiber).

  The variable optical attenuator 65 is optically coupled between the optical amplification unit 64 (first optical amplification unit) and the optical amplification unit 67 (second optical amplification unit) for amplifying the signal light L2. Then, the signal light L2 that has been optically amplified by the optical amplifier 64 and input is input, loss is given to the signal light L2, and the optical signal is output to the optical amplifier 67. The loss imparted to the signal light L2 by the variable optical attenuator 65 is variable.

  The optical coupler 66 receives the signal light L2 that is output from the variable optical attenuator 65 and arrives, and also receives the pumping light L4 that is output from the pumping light source 74 and receives the signal light L2 and the pumping light L4. Output to the optical amplifier 67. The optical amplifying unit 67 receives the signal light L2 and the pumping light L4 that are output from the optical coupler 66, and is excited by the pumping light L4 to optically amplify and output the signal light L2. Is a rare earth element-doped optical fiber such as EDF. The optical coupler 68 receives the signal light L2 output after being amplified by the optical amplifier 67, outputs the signal light L2 from the output end 61b to the outside, and branches a part of the signal light L2. Output to the light receiving element 72.

  The light receiving element 71 outputs an electric signal Sm1 indicating the light intensity of the signal light L2 that is branched by the optical coupler 62. The light receiving element 72 outputs an electric signal Sm2 indicating the light intensity of the signal light L2 branched and reached by the optical coupler 68. The pumping light source 73 outputs pumping light L3 having a wavelength capable of pumping the optical amplifying unit 64 to the optical coupler 63. The pumping light source 74 outputs pumping light L4 having a wavelength capable of pumping the optical amplifying unit 67 to the optical coupler 66. As the light receiving elements 71 and 72, photodiodes are preferably used. As the excitation light sources 73 and 74, semiconductor laser light sources are preferably used.

  Based on the electrical signals Sm1 and Sm2 provided from the light receiving elements 71 and 72, the control unit 75 calculates the total gain generated in the optical amplification units 64 and 67 while considering the loss in the variable optical attenuator 65, The light intensity of the pumping lights L3 and L4 is controlled so that the total gain becomes a predetermined gain. That is, the control unit 75 provides drive voltages Vd3 and Vd4 of appropriate magnitudes to the excitation light sources 73 and 74, respectively, based on the electrical signals Sm1 and Sm2 provided from the light receiving elements 71 and 72.

  Based on the electrical signal Sm1 provided from the light receiving element 71, the control unit 76 controls the loss of the variable optical attenuator 65 so that the light intensity of the signal light L2 becomes a predetermined magnitude. That is, the control unit 76 provides the variable optical attenuator 65 with an appropriate magnitude of the drive voltage Vd5 based on the electrical signal Sm1 provided from the light receiving element 71.

  Here, the control units 75 and 76 of the present embodiment have the same configuration as the control unit 15 shown in FIG. That is, the control units 75 and 76 include the arithmetic processing circuit 21, the firmware storage unit 22, the drive voltage storage unit 23, the voltage holding unit 40 including the communication state holding unit 41, and the voltage generation unit illustrated in FIG. 30. However, the voltage generation unit 30 of the control unit 76 may include at least the DA converter 34a, the high voltage amplification unit 35a, and the drive unit 36a illustrated in FIG.

  The control unit 75 supplies the drive voltage Vd3 to the excitation light source 73 and controls the magnitude of the drive voltage Vd3. Further, the control unit 75 supplies the drive voltage Vd4 to the excitation light source 74 and controls the magnitude of the drive voltage Vd4. The control unit 76 supplies the drive voltage Vd5 to the variable optical attenuator 65 and controls the magnitude of the drive voltage Vd5.

  As with the control unit 15 shown in FIG. 3, the control units 75 and 76 include the voltage holding unit 40. Therefore, when updating the firmware stored in the firmware storage unit 22, the calculation processing circuit 21 Regardless of the operating state, the output voltage from the voltage generator 30 is a constant voltage. Therefore, when the firmware is updated, an unexpected operation of the optical device 10 (in this embodiment, the pumping light sources 73 and 74 and the variable optical attenuator 65) can be avoided and a good communication state can be maintained. Further, since the control units 75 and 76 have the same configuration as that of the control unit 15 shown in FIG. 3, other effects of the first embodiment can be obtained in the same manner.

  The optical module for an optical communication system and the method for updating the firmware of the optical module for an optical communication system according to the present invention are not limited to the embodiments described above, and various other modifications are possible. For example, in each of the above-described embodiments, a MEMS mirror, a pumping light source, and a variable optical attenuator are illustrated as examples of the optical device. However, the optical device in the present invention is used in an optical communication system and driven by a driving voltage. Anything is acceptable and not limited to these.

DESCRIPTION OF SYMBOLS 1A, 1B, 1C ... Optical module, 10 ... Optical device, 12 ... MEMS mirror, 13 ... Lens, 15 ... Control part, 20 ... Arithmetic processing chip, 21 ... Arithmetic processing circuit, 22 ... Firmware storage part, 23 ... Drive voltage Storage unit, 30 ... Voltage generation unit, 33 ... Chip selector input terminal, 34a, 34b ... DA converter, 35a, 35b ... High voltage amplification unit, 36a, 36b ... Drive unit, 40 ... Voltage holding unit, 41 ... Communication state holding 51, input optical waveguide, 52 ... output optical waveguide, 62, 63, 66, 68 ... optical coupler, 64, 67 ... optical amplification unit, 65 ... variable optical attenuator, 71, 72 ... light receiving element, 73 74, excitation light source, 75, 76, control unit, L1, L2, signal light, L3, L4, excitation light, Vd, drive voltage.

Claims (10)

An optical module used in an optical communication system,
An optical device driven by a driving voltage;
An arithmetic processing chip including an arithmetic processing circuit that operates in accordance with predetermined firmware and generates an electrical control signal indicating the magnitude of the drive voltage;
A voltage provided outside the arithmetic processing chip, having an input terminal for receiving the control signal from the arithmetic processing chip, and an output terminal for providing the drive voltage having a magnitude corresponding to the control signal to the optical device. A generator,
An optical communication system comprising: a voltage holding unit that sets an output voltage from the output terminal of the voltage generation unit to a constant voltage regardless of an operation state of the arithmetic processing circuit when updating the firmware. Optical module. The voltage generation unit further includes a chip selector input terminal for inputting a chip selector signal, and outputs the driving voltage and the constant voltage according to the control signal based on the chip selector signal. switching,
2. The optical communication system according to claim 1, wherein the voltage holding unit generates the chip selector signal so that the voltage generation unit outputs the constant voltage when the firmware is updated. Optical module.   The voltage holding unit is connected between the arithmetic processing chip and the input terminal of the voltage generation unit, and instead of the control signal indicating the magnitude of the drive voltage when the firmware is updated. The optical module for an optical communication system according to claim 1, wherein a control signal indicating the constant voltage is provided to the input terminal of the voltage generation unit.   The optical module for an optical communication system according to any one of claims 1 to 3, wherein the constant voltage is equal to the drive voltage immediately before the firmware update. The firmware comprises a software program;
5. The optical communication system according to claim 1, wherein the arithmetic processing circuit includes a CPU that operates by reading the software program from a memory that stores the software program. 6. Optical module.   The optical module for an optical communication system according to any one of claims 1 to 4, wherein the arithmetic processing circuit includes rewritable hardware capable of rewriting an internal circuit represented by the firmware. .   The optical module for an optical communication system according to claim 1, wherein the optical device is an optical deflection element for a wavelength selective switch.   The optical module for an optical communication system according to claim 1, wherein the optical device is a pumping light source that supplies pumping light to an optical amplifying unit for amplifying signal light. .   The optical device is a variable optical attenuator optically coupled between a first optical amplifying unit and a second optical amplifying unit for amplifying signal light. The optical module for optical communication systems as described in any one of -6. An arithmetic processing chip including an arithmetic processing circuit that operates according to predetermined firmware and generates an electrical control signal indicating the magnitude of the driving voltage to the optical device driven by the driving voltage; and outside the arithmetic processing chip A method of updating the firmware in an optical module that is provided and includes a voltage generation unit that provides the optical device with the drive voltage having a magnitude corresponding to the control signal,
A first step of storing and storing setting information immediately before updating the firmware, with the output voltage from the output terminal of the voltage generator set to a constant voltage;
A second step of rewriting the firmware;
A third step of resetting the arithmetic processing circuit and restoring the setting information immediately before the firmware update to continue the operation;
A method for updating firmware of an optical module for an optical communication system, comprising:

Images