Light control device, repeater, and control method for light control device

Abstract

In order to provide technologies for implementing a control light receiving function and a signal light monitoring function by means of a simple configuration, this light control device comprises: a wavelength-variable filter having a variable transmissive wavelength for transmitting input light; a photoelectric conversion means for converting output light from the wavelength-variable filter into an electric signal; and a control means for setting a transmissive wavelength and controlling a communication device on the basis of an electric signal corresponding to the transmissive wavelength.

Description

[Technical Field]

[0001] The present invention relates to an optical control device, a control method for an optical control device, and a recording medium, and more particularly to an optical control device, a control method for an optical control device, and a recording medium used in an optical submarine cable system. [Background technology]

[0002] To accommodate a variety of network configurations, submarine equipment used in optical submarine cable systems, such as repeaters, branching devices, and ROADMs (reconfigurable optical add drop multiplexers), are becoming increasingly sophisticated. In addition to the ability to monitor the status of the submarine equipment and transmission quality such as the spectrum of signal light, submarine equipment is also required to receive control light for the submarine equipment and execute control according to the control commands extracted from the control light.

[0003] A typical submarine device must be equipped with an opto-electrical converter and a control unit to control the submarine device using control light and to monitor the signal light. The opto-electrical converter generates an electrical signal corresponding to the intensity of the received light. The control unit controls the submarine device and monitors the signal light based on the electrical signal output from the opto-electrical converter. To monitor the spectrum of the signal light, a device such as an OCM (Optical Channel monitor) or a WSS (Wavelength Selective Switch) is implemented inside the submarine device.

[0004] In relation to the present invention, Patent Document 1 describes an optical repeater system equipped with a monitoring loopback circuit. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 05-344067 Summary of the Invention [Problem to be solved by the invention]

[0006] Generally, control light and signal light are transmitted simultaneously at different wavelengths. Therefore, in order to receive the control light and signal light independently, the submarine equipment must be equipped with a demultiplexer that separates the control light and signal light by wavelength, a first opto-electrical converter for receiving the control light, and a second opto-electrical converter for receiving the control light. In other words, implementing the control light receiving function and signal light monitoring function in the submarine equipment requires many components, resulting in a complex circuit configuration. Furthermore, this poses the problem of requiring a large area for implementing these components. (Object of the invention) An object of the present invention is to provide a technique for realizing a function for receiving control light and a function for monitoring signal light with a simple configuration. [Means for solving the problem]

[0007] The optical control device of the present invention comprises a wavelength-tunable filter having a variable transmission wavelength for transmitting input light, a photoelectric conversion means for converting the output light of the wavelength-tunable filter into an electrical signal, and a control means for setting the transmission wavelength and controlling a communication device based on the electrical signal corresponding to the transmission wavelength.

[0008] The control method for an optical control device of the present invention includes the steps of setting a transmission wavelength for transmitting input light in a wavelength-variable filter, converting the output light of the wavelength-variable filter into an electrical signal, and controlling a communication device based on the electrical signal corresponding to the transmission wavelength. The recording medium of the present invention records a program for causing a computer of an optical control device to execute the following steps: setting a transmission wavelength for transmitting input light in a wavelength-variable filter; converting the output light of the wavelength-variable filter into an electrical signal; and controlling a communication device based on the electrical signal corresponding to the transmission wavelength. [Effects of the Invention]

[0009] The present invention provides a technique for realizing a function for receiving control light and a function for monitoring signal light with a simple configuration. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a block diagram showing an example of the configuration of a light control device 100 according to a first embodiment. [Figure 2] 4 is a flowchart showing an example of the operation of the light control device 100. [Figure 3] FIG. 1 is a diagram illustrating an example of the configuration of an optical submarine cable system 1 according to a second embodiment. [Figure 4] FIG. 10 is a block diagram showing a first modified example of the repeater 40 in the second embodiment. [Figure 5] FIG. 10 is a block diagram showing a second modified example of the repeater 40 in the second embodiment. [Figure 6] FIG. 10 is a block diagram showing an example of the configuration of a repeater 41 in the third embodiment. [Figure 7] 10 is a flowchart showing an example of an operation procedure of the repeater 41. [Figure 8] FIG. 10 is a block diagram showing an example of the configuration of a repeater 42 in a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] An embodiment of the present invention will be described below with reference to the drawings. Arrows shown in the drawings are intended to illustrate the direction of signals or the order of processing, and are not intended to limit the scope of the present invention. In the embodiments and drawings, elements already mentioned are given the same reference numerals, and duplicate explanations will be omitted.

[0012] (First embodiment) FIG. 1 is a block diagram showing an example of the configuration of an optical control device 100 in the first embodiment. The optical control device 100 includes a wavelength tunable filter 110, an opto-electric conversion unit 120, and a control unit 130. FIG. 1 also shows a communication device 10 connected to the control unit 130. The optical control device 100 controls some or all of the functions of the communication device 10. The optical control device 100 may be included in the communication device 10. For example, if the communication device 10 is a repeater, the optical control device 100 may be provided in the repeater as an optical control unit. In this case, the optical control unit controls some or all of the functions of the repeater.

[0013] The tunable filter 110 outputs a partial wavelength band of the light input to the tunable filter 110 (input light) as output light. A MEMS (Micro Electro Mechanical System) or a WSS (Wavelength Selective Switch) may be used as the tunable filter 110. The wavelength band (transmission wavelength) of light transmitted by the tunable filter 110 is set by an electrical signal output by the control unit 130. That is, the control unit 130 controls the transmission wavelength of the tunable filter 110. The transmission wavelength width may be a width that transmits multiple carriers contained in the input light, or may be a width that transmits only one optical carrier. The photoelectric conversion unit 120 serves as photoelectric conversion means that converts the output light of the tunable filter 110 into an electrical signal. The photoelectric conversion unit 120 includes, for example, a photodiode, and outputs an electrical signal with an amplitude corresponding to the intensity of the output light of the tunable filter 110. The electrical signal output from the photoelectric conversion unit 120 is output to the control unit 130. The control unit 130 sets the transmission wavelength of the tunable filter 110 and controls the communication device 10 based on the electrical signal corresponding to the transmission wavelength input from the photoelectric conversion unit 120. The control unit 130 is an electrical circuit that serves as a control means.

[0014] By appropriately setting the transmission wavelength of the tunable filter 110, when light in which control light and signal light are wavelength-multiplexed is input to the tunable filter 110, the control unit 130 can independently obtain the control light and the electrical signals corresponding to the respective electrical signals from the opto-electrical conversion unit 120. The control light is an optical signal containing a control command, and has a wavelength λ1. A general procedure can be applied to include the control command in the control light. The signal light is, for example, an optical signal containing user data, and has a wavelength λ2. Furthermore, in this embodiment and the following embodiments, it is assumed that the wavelength λ1 of the control light and the wavelength λ2 of the signal light do not overlap.

[0015] When the control unit 130 sets the transmission wavelength of the wavelength-tunable filter 110 to λ1, the control light with wavelength λ1 passes through the wavelength-tunable filter 110, and the signal light with wavelength λ2 is blocked by the wavelength-tunable filter 110. As a result, the control unit 130 can obtain an electrical signal corresponding to the intensity of the control light from the photoelectric conversion unit 120. The control unit 130 extracts a control command from the electrical signal obtained from the photoelectric conversion unit 120 according to a predetermined procedure. The control unit 130 then executes the extracted control command. The control unit 130 may output an instruction to control the communication device 10 based on the extracted control command. This allows the control unit 130 to control the communication device.

[0016] Furthermore, when the control unit 130 sets the transmission wavelength to λ2, the control light with wavelength λ1 is blocked by the wavelength-tunable filter 110, while the signal light with wavelength λ2 is transmitted through the wavelength-tunable filter 110. As a result, the control unit 130 can obtain an electrical signal from the opto-electrical conversion unit 120, having an amplitude corresponding to the intensity of the signal light. In this case, the control unit 130 can monitor the intensity of the signal light using the amplitude of the electrical signal obtained from the opto-electrical conversion unit 120. Furthermore, when the wavelength of the signal light is in the range of λ3-λ4, the control unit 130 can obtain the spectrum of the signal light by sweeping the transmission wavelength between λ3 and λ4 in a bandwidth corresponding to the wavelength resolution required for monitoring. The control unit 130 may similarly obtain a spectrum corresponding to the wavelength range of the control light. The control unit 130 may further include a storage unit including a semiconductor memory, a fixed magnetic disk, or the like. The storage unit stores the extracted control command, its execution result, and the obtained spectrum data. The control unit 130 may also have a function of notifying the communication device 10 of the contents stored in the storage unit.

[0017] 2 is a flowchart showing an example of the operation of the light control device 100. The control unit 130 sets the transmission wavelength of the wavelength-tunable filter 110 (step S01 in FIG. 2). The photoelectric conversion unit 120 converts the output light from the wavelength-tunable filter 110 into an electrical signal (step S02). Then, the control unit 130 controls the communication device based on the electrical signal corresponding to the transmission wavelength (step S03).

[0018] The optical control device 100 having such a configuration can achieve the function of receiving control light and the function of monitoring signal light by the wavelength tunable filter 110, the optical-electrical conversion unit 120, and the control unit 130, without providing a demultiplexer or an optical-electrical conversion unit dedicated to each light. As a result, it is possible to reduce the number of optical-electrical conversion units and the mounting area. This contributes to lower power consumption and miniaturization of the optical control device 100 and the system including it. In this way, the optical control device 100 of the first embodiment can achieve the function of receiving control light and the function of monitoring signal light with a simple configuration.

[0019] (Second embodiment) FIG. 3 is a diagram showing an example of the configuration of an optical submarine cable system 1 according to the second embodiment. The optical submarine cable system 1 is an optical communication system in which a terminal station 20, a repeater 40, and a terminal station 30 are connected by submarine cables 50 and 51. The terminal stations 20 and 30 are installed on land. The repeater 40 is a submarine device installed on the seabed. The terminal station 20 and the terminal station 30 communicate with each other via the repeater 40. The terminal station 20 transmits light obtained by wavelength-multiplexing control light with wavelength λ1 and signal light with wavelength λ2 onto the submarine cable 50. The control light may include a control command for controlling the repeater 40. The signal light is an optical signal transmitted from the terminal station 20 to the terminal station 30 and includes data of a user of the optical submarine cable system 1. The repeater 40 receives the control light and the signal light from the terminal station 20 and transmits light corresponding to the received signal to the terminal station 30 via the submarine cable 51. At least one of a submarine cable branching device and another repeater may be disposed between the terminal station 20 and the repeater 40 and between the repeater 40 and the terminal station 30 .

[0020] The repeater 40 comprises an optical control unit 200 and a processing unit 300. The processing unit 300 is a functional block including a circuit that provides the repeating function of the repeater 40. For example, the processing unit 300 comprises an optical amplifier and amplifies the signal light output to the terminal station 30. Alternatively, the processing unit 300 may comprise an optical filter or an optical equalizer and manipulate the spectrum of the signal light output to the terminal station 30. The processing unit 300 may comprise at least one of an optical amplifier, an optical filter, and an optical equalizer. However, the configuration and functions of the processing unit 300 are not limited to these. The processing unit 300 may operate under control from the optical control unit 200.

[0021] The optical control unit 200 is configured by adding an optical coupler 140 to the optical control device 100 of the first embodiment. The optical coupler 140 branches the light received from the terminal station 20 (i.e., light in which control light with wavelength λ1 and signal light with wavelength λ2 are wavelength-multiplexed) into two directions. One of the branched lights is output to the tunable filter 110. The other of the branched lights is output to the terminal station 30. The other of the branched lights may be processed by the processing unit 300. The optical coupler 140 is, for example, a one-input, two-output optical directional coupler.

[0022] The configurations and operations of the tunable filter 110, the opto-electrical conversion unit 120, and the control unit 130 included in the optical control unit 200 are the same as those in the first embodiment. That is, the tunable filter 110 receives control light with a wavelength λ1 and signal light with a wavelength λ2 transmitted by the terminal station 20. Then, the control unit 130 sets the transmission wavelength of the tunable filter 110 to the wavelength λ1, thereby obtaining an electrical signal corresponding to the intensity of the control light transmitted by the terminal station 20 from the opto-electrical conversion unit 120. As a result, the control unit 130 can control the repeater 40 in accordance with the control command extracted from the electrical signal.

[0023] Moreover, by setting the transmission wavelength to λ2, the control unit 130 can obtain from the opto-electrical conversion unit 120 an electrical signal corresponding to the intensity of the signal light transmitted by the terminal station 20. Furthermore, by sweeping the transmission wavelength of the tunable filter 110, the control unit 130 can obtain the spectrum of the signal light transmitted by the terminal station 20. The control unit 130 may similarly obtain the spectrum of the control light. Meanwhile, since the other light branched by the optical coupler 140 is output to the terminal station 30, the repeater 40 maintains its signal light relay function. The repeater 40 may have a function to transmit to the terminal station 30 data including at least one of the control command and its execution result obtained by the control unit 130 from the control light, and information on the intensity and spectrum obtained from the signal light. This function allows the terminal station 30 to check the status of the optical control unit 200.

[0024] The transmission wavelength of the tunable filter 110 and the time at which the transmission wavelength is set (i.e., information on the timing at which these settings are made) are held as data in the control unit 130. This timing information may be stored in advance in the control unit 130 based on, for example, the specifications of the control light of the optical submarine cable system 1 in which the repeater 40 is used. Alternatively, the repeater 40 may obtain the timing information from, for example, the terminal station 20 using the repeater 40's external communication function, and store the timing information in the control unit 130.

[0025] In this way, the repeater 40 of the second embodiment can achieve the function of receiving control light and the function of monitoring signal light by the tunable filter 110, the photoelectric conversion unit 120, and the control unit 130, without providing a dedicated photoelectric conversion unit for each light. As a result, the repeater 40 can reduce the number of optical components and the mounting area required to achieve the function of receiving control light and the function of monitoring signal light, while maintaining the function of repeating signal light. This contributes to lower power consumption and a smaller size of the optical submarine cable system 1 equipped with the repeater 40.

[0026] (First modified example of the second embodiment) FIG. 4 is a block diagram showing a first modified example of the repeater 40 in the second embodiment. In FIG. 4, the processing unit 300 includes an optical amplifier 301. The optical amplifier 301 includes a control circuit and amplifies the control light and signal light branched by the optical coupler 140 in accordance with instructions from the control unit 130. The light amplified by the optical amplifier 301 is output to the terminal station 30. For example, the control unit 130 sets the transmission wavelength of the tunable filter 110 so that the opto-electrical conversion unit 120 outputs an electrical signal corresponding to the control light to the control unit 130. The control unit 130 then controls the optical amplifier 301 based on the extracted control command. If the control command is an instruction to specify the output level of the optical amplifier 301, the optical amplifier 301 controls the output level to approach the specified level. If the optical amplifier 301 is an optical fiber amplifier, the optical amplifier 301 may control the output level of a pumping light source included in the optical amplifier 301 so that the output level becomes the value specified by the control unit 130. The optical amplifier 301 can adjust the level of the signal light.

[0027] Alternatively, the control unit 130 may set the transmission wavelength of the wavelength-tunable filter 110 so that the optoelectric conversion unit 120 outputs an electrical signal corresponding to the signal light to the control unit 130. In this case, the control unit 130 estimates the level (input level) of the signal light input to the repeater 40 from the electrical signal corresponding to the signal light. If there is a large difference between the estimated input level and a predetermined value, the control unit 130 controls the gain of the optical amplifier 301 so as to compensate for the difference. By controlling the gain of the optical amplifier 301 in this manner, it is possible to suppress fluctuations in the level of the signal light output from the repeater 40 due to fluctuations in the input level.

[0028] The terminal station 20 transmits control light including a control command so that the optical amplifier 301 operates with desired characteristics. Predetermined values ​​of parameters (e.g., input level, output level, gain) used to control the optical amplifier 301 may be stored in advance in the control unit 130, or may be notified from the terminal station 20 by another control command.

[0029] It is also possible to control the level of light output from the repeater 40 by using a variable optical attenuator instead of the optical amplifier 301. For example, if the control command specifies the attenuation amount of the optical attenuator, the control unit 130 controls the variable optical attenuator so that the attenuation amount of the variable optical attenuator becomes that value.

[0030] (Second Modification of the Second Embodiment) 5 is a block diagram showing a second modified example of the repeater 40 in the second embodiment. In FIG. 5, the processing unit 300 includes an optical equalizer 302. The attenuation of the optical equalizer 302 is set by the control unit 130 to a value that varies depending on the wavelength. By using the optical equalizer 302, the spectrum of the signal light output to the submarine cable 51 can be adjusted. When the signal light is a wavelength-multiplexed optical signal including multiple optical carriers with different wavelengths, the optical equalizer 302 may adjust the spectrum of the signal light so as to reduce the level difference between the optical carriers. The optical equalizer 302 may also adjust the spectrum of the control light. The light output from the optical equalizer 302 is output to the terminal station 30 via the submarine cable 51.

[0031] For example, the control unit 130 sweeps the transmission wavelength of the tunable filter 110 so that the photoelectric conversion unit 120 outputs to the control unit 130 an electrical signal corresponding to the intensity corresponding to the wavelength of the signal light. This allows the control unit 130 to acquire the spectrum of the signal light (i.e., the relationship between the wavelength and intensity of the signal light). If the acquired spectrum differs from a reference spectrum, the control unit 130 controls the characteristics of the optical equalizer 302 (i.e., the amount of attenuation corresponding to the wavelength) so as to reduce the difference. This allows the spectrum of the signal light output from the repeater 40 to be modified to a more desirable shape.

[0032] The terminal station 20 transmits control light including a control command so that the optical equalizer 302 has desired characteristics. The predetermined values ​​of the parameters (e.g., the spectrum of the reference signal light) used to control the optical equalizer 302 may be stored in advance in the control unit 130, or may be notified from the terminal station 20 by another control command.

[0033] Furthermore, if the control command extracted from the control light is a command to set the spectrum of the signal light, the control unit 130 sets the characteristics of the optical equalizer 302 to a shape corresponding to the content of the control command. For example, if the control command is a command to flatten the spectrum of the signal light, the control unit 130 controls the wavelength characteristics of the optical equalizer 302 so that the wavelength characteristics are inverse to the spectrum of the signal light acquired by the control unit 130.

[0034] (Third embodiment) 6 is a block diagram showing an example of the configuration of a repeater 41 in the third embodiment. The repeater 41 includes an optical control unit 201 and a processing unit 300. The optical control unit 201 is obtained by adding an optical coupler 141 and an optical switch 150 to the optical control unit 200 of the second embodiment. The repeater 41 can be used in place of the repeater 40 in the optical submarine cable system 1 of FIG. 3.

[0035] The optical switch 150 is disposed between the output of the tunable filter 110 and the input of the photoelectric conversion unit 120. The optical switch 150 is a 1×2 optical switch, and outputs the light input from the tunable filter 110 to one of two outputs in response to an instruction from the control unit 130. One output of the optical switch 150 is connected to the photoelectric conversion unit 120, and the other output is connected to one input of the optical coupler 141.

[0036] The optical coupler 141 is a two-input, one-output (2×1) optical coupler, such as an optical directional coupler. The optical coupler 141 couples the input light and outputs the combined light to the terminal station 30. One of the inputs of the optical coupler 141 is connected to one of the outputs of the optical coupler 140. The other input of the optical coupler 141 is connected to the other of the outputs of the optical switch 150. In other words, the optical coupler 141 can combine one of the lights branched by the optical coupler 140 with the light output from the wavelength tunable filter 110 via the optical switch 150.

[0037] When the control unit 130 receives an electrical signal corresponding to the control light from the opto-electrical conversion unit 120, the control unit 130 sets the transmission wavelength of the tunable filter 110 in advance so that only the control light passes through the tunable filter 110. The control unit 130 also controls the optical switch 150 in advance so that the control light that has passed through the tunable filter 110 is received by the opto-electrical conversion unit 120. As a result, the control unit 130 can receive an electrical signal corresponding to the control light from the opto-electrical conversion unit 120. Information on the times at which the tunable filter 110 and the optical switch 150 are switched (i.e., the timing of these controls) is held as data in the control unit 130. This timing information may be stored in advance in the control unit 130 based on, for example, the specifications of the control light of the optical submarine cable system 1 in which the repeater 41 is used. The repeater 41 may also acquire timing information from, for example, the terminal station 20 using its external communication function provided in the repeater 41, and store the timing information in the control unit 130.

[0038] 7 is a flowchart showing an example of the operation procedure of the repeater 41. The control unit 130 sets the transmission wavelength of the tunable filter 110 (step S11 in FIG. 7). Then, the light branched by the optical coupler 140 is input to the tunable filter 110 (step S12). If the light passing through the tunable filter 110 is signal light (step S13: signal light), the signal light is received by the photoelectric conversion unit 120, which generates an electrical signal corresponding to the signal light (step S14). The control unit 130 executes predetermined processing based on the electrical signal generated from the signal light (for example, generating and storing data on the spectrum of the signal light) (step S15).

[0039] On the other hand, if the light passing through the tunable filter 110 is control light (step S13: control light), the control light is received by the photoelectric conversion unit 120. The photoelectric conversion unit 120 generates an electrical signal corresponding to the control light (step S16). The control unit 130 executes a control command extracted from the electrical signal corresponding to the control light (step S17).

[0040] When the terminal station 20 finishes transmitting the control light containing the control command, it transmits unmodulated (continuous wave, CW) control light. The unmodulated control light does not contain a control command. On the other hand, when the control command execution is finished (step S18: YES), the control unit 130 connects the output of the optical switch 150 to the optical coupler 141 (step S19). Then, the control unit 130 modulates the unmodulated control light output from the wavelength-tunable filter 110 by temporally changing the transmission wavelength of the wavelength-tunable filter 110 (step S20). In step S20, for example, while the control light is unmodulated, the control unit 130 controls the wavelength-tunable filter 110 so that only the control light passes through during period T1, and that neither the control light nor the signal light passes through during the following period T2. By repeating this, the repeater 41 can transmit the modulated control light to the terminal station 30 as a pulse-width modulated signal using T1 and T2.

[0041] The control light pulse-width modulated by the wavelength-tunable filter 110 (hereinafter referred to as "response light") may include information about the spectrum of the signal light acquired by the control unit 130 and information about the execution result of the control command. The modulation content (e.g., the values ​​of T1 and T2) in the wavelength-tunable filter 110 and the corresponding information are shared in advance between the repeater 40 and the terminal station 30. The information included in the table may be notified in advance to the control unit 130 as data included in the control command. The terminal station 30 can extract the information added to the response light by the repeater 40 by demodulating the response light. For example, the terminal station 30 can measure the period T1 during which the response light is received and the period T2 during which the control light is not received, and extract the information included in the response light by referring to the table using these values.

[0042] Note that, as long as there is no problem with demodulating the response light in the terminal station 30, the control light input to the wavelength-tunable filter 110 when the response light is generated in the repeater 41 does not need to be unmodulated. Also, the response light output by the repeater 41 may be received by another submarine device (e.g., a repeater) having the same function as the optical control unit 200 or 201, and the submarine device may process the response light as control light. The repeater 41 generates response light including a control command, and the other submarine device that receives this extracts and executes the control command from the response light, so that the repeater 41 can control the other submarine device according to the execution result of the control command in the repeater 41.

[0043] In the repeater 41 of this embodiment, the optical control unit 201 generates response light by modulating the control light received from the terminal station 20 using a wavelength-tunable filter. With this configuration, the repeater 41 can transmit information to the terminal station 30 or other undersea equipment without providing a light source for transmitting information and its driving circuit. For example, the optical control unit 201 can realize, with a simple configuration, a repeater 41 that further has a command / response function for receiving control light and transmitting a control result (response) according to a control command extracted from the control light.

[0044] (Fourth embodiment) Fig. 8 is a block diagram showing an example of the configuration of the repeater 42 in the fourth embodiment. The repeater 42 includes an optical control unit 202 and processing units 300 and 310. The optical control unit 202 has a configuration in which optical couplers 142 and 143 and optical switches 151 and 152 are added to the optical control unit 200 of the third embodiment. The processing units 300 and 310 are functional blocks that provide the repeater function of the repeater 40, and these functions were exemplified in the second embodiment and its modified example. Note that in Fig. 8, the intersections of lines indicating connections between blocks do not indicate coupling or distribution, except for the points indicated by black circles.

[0045] The repeater 42 has a function to process the signal light and control light transmitted from the terminal station 20 to the terminal station 30, as well as a function to process the signal light and control light transmitted from the terminal station 30 to the terminal station 20. The terminal station 30 transmits the control light and signal light to the repeater 42 via the submarine cable 52. The repeater 42 processes the control light and signal light received from the terminal station 30, and transmits light corresponding to the processing results to the terminal station 20 via the submarine cable 53.

[0046] Hereinafter, the direction from the terminal station 20 to the terminal station 30 is referred to as the "downstream direction," and the direction from the terminal station 30 to the terminal station 20 is referred to as the "upstream direction." In the second and third embodiments, the operation of the repeaters 40 and 41 for downstream light was described. The repeater 42 of this embodiment can perform the same processing for upstream light as the processing for downstream light in the third embodiment. In the repeater 42 of this embodiment, the processing unit 300 provides the repeating function for downstream light, and the processing unit 310 provides the repeating function for upstream light. The wavelengths of the control light and signal light for the upstream direction may be the same as or different from those for the downstream direction. The control unit 130 stores information on the wavelength and reception time of the control light and the wavelength and reception time of the signal light for each of the downstream and upstream directions as data. Based on this data, the control unit 130 controls the optical switches 150-152 and the wavelength tunable filter 110 at appropriate timing so that the following processing is performed for the upstream light and the downstream light.

[0047] The optical coupler 140 branches the input downstream light, outputs one of the branched outputs to the optical switch 151, and outputs the other output to the optical coupler 141. The optical coupler 142 branches the input upstream light, outputs one of the branched outputs to the optical switch 151, and outputs the other output to the optical coupler 143.

[0048] The optical switch 151 is a 2×1 optical switch with two inputs and one output, and outputs either the downstream light branched by the optical coupler 141 or the upstream light branched by the optical coupler 142 to the wavelength-tunable filter 110. The optical switch 152 is a 1×2 optical switch with one input and two outputs, and outputs the light output from the optical switch 150 to the optical coupler 141 or 143. When the control light is modulated in the wavelength-tunable filter 110, the optical switch 150 is controlled so that the modulated light is output to the optical switch 152.

[0049] When the optical control unit 202 processes downstream light, the optical switch 151 is controlled so that the downstream light is input to the tunable filter 110. When the downstream control light is modulated in the tunable filter 110, the optical switch 152 is controlled so that the modulated control light is output to the optical coupler 141. On the other hand, when the optical control unit 202 processes upstream light, the optical switch 151 is controlled so that the upstream light is input to the tunable filter 110. When the upstream control light is modulated in the tunable filter 110, the optical switch 152 switches the optical path so that the modulated control light is output to the optical coupler 143.

[0050] The repeater 42 having such a configuration shares one optical control unit 202 for processing downstream light and upstream light. As a result, in addition to the effects of the repeaters described in the second and third embodiments, the repeater 42 has the effect of reducing the number of components and mounting area of ​​a repeater that repeats upstream light and downstream light.

[0051] The embodiments of the present invention can be described as follows, but are not limited to these.

[0052] (Appendix 1) a wavelength tunable filter that can tune the transmission wavelength of input light; a photoelectric conversion means for converting the output light of the wavelength tunable filter into an electrical signal; a control unit that sets the transmission wavelength and outputs an instruction to control a communication device based on the electrical signal corresponding to the transmission wavelength; A light control device comprising:

[0053] (Appendix 2) When the input light is a wavelength-multiplexed light of a control light and a signal light, the control means sets the transmission wavelength to the wavelength of the control light and controls the communication device based on the electrical signal. 1. A light control device as described in Appendix 1.

[0054] (Appendix 3) When the input light is a wavelength-multiplexed light of a control light and a signal light, the control unit sets the transmission wavelength to the wavelength of the signal light and monitors the signal light based on the electrical signal. 1. A light control device as described in Appendix 1.

[0055] (Appendix 4) the control unit controls the tunable filter to sweep the transmission wavelength, thereby obtaining a spectrum of at least one of the control light and the signal light. 1. A light control device according to claim 2 or 3.

[0056] (Appendix 5) a first optical coupler that branches the input light and guides one of the branched input lights to the wavelength tunable filter; 5. A light control device according to any one of claims 2 to 4.

[0057] (Appendix 6) a second optical coupler and a first optical switch; the first optical coupler connects the other branched input light to one input of the second optical coupler; the first optical switch outputs the output light of the wavelength tunable filter to either the other input of the second optical coupler or the photoelectric conversion means; the tunable filter outputs a response signal corresponding to the control light by controlling the transmission wavelength; the first optical switch outputs the response signal to the second optical coupler; the second optical coupler couples the output of the first optical switch with the other of the input light branched by the first optical coupler. 10. A light control device as described in Appendix 5.

[0058] (Appendix 7) a second optical switch that outputs one of the light input from the first optical coupler and the light input from another optical line to the wavelength tunable filter; a third optical switch arranged between one of the outputs of the first optical switch and one of the inputs of the second optical coupler, and connecting one of the outputs of the first optical switch to one of the inputs of the second optical coupler and one of the other optical lines; 7. The light control device according to claim 6, comprising:

[0059] (Appendix 8) A repeater including the optical control device according to any one of Supplementary Note 2 to 7, the control means controls the repeater as the communication device; Repeater.

[0060] (Appendix 9) 9. The repeater according to claim 8, further comprising a processing means for performing predetermined processing on at least one of the control light and the signal light based on an instruction from the control means.

[0061] (Appendix 10) 10. The repeater of claim 9, wherein the processing means comprises at least one of an optical amplifier or an optical equalizer.

[0062] (Appendix 11) A repeater according to any one of appendices 8 to 10; a terminal station that transmits the control light and the signal light to the repeater; An optical submarine cable system comprising:

[0063] (Appendix 12) The wavelength that transmits the input light is set in the tunable filter. converting the output light of the wavelength tunable filter into an electrical signal; controlling a communication device based on the electrical signal corresponding to the transmission wavelength; A method for controlling a light control device.

[0064] (Appendix 13) When the input light is a wavelength-multiplexed light of a control light and a signal light, The transmission wavelength is set to the wavelength of the control light, Controlling the communication device based on the electrical signal. A method for controlling a light control device according to claim 12.

[0065] (Appendix 14) When the input light is a wavelength-multiplexed light of a control light and a signal light, The transmission wavelength is set to the wavelength of the signal light, acquiring optical characteristics of the signal light based on the electrical signal; A method for controlling a light control device according to claim 12.

[0066] (Appendix 15) acquiring a spectrum of at least one of the control light and the signal light by controlling the tunable filter so as to sweep the transmission wavelength; A method for controlling a light control device according to claim 13 or 14.

[0067] Although the present invention has been described above with reference to the embodiments, the present invention is not limited to the above-described embodiments. Various modifications that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

[0068] Furthermore, the configurations described in the respective embodiments are not necessarily mutually exclusive, and the functions and effects of the present invention may be achieved by a configuration that combines all or part of the above-described embodiments.

[0069] Some or all of the functions and procedures described in each of the above embodiments may be realized by a central processing unit (CPU) included in the control unit 130 executing a program. The CPU may be provided in a location other than the control unit 130. The program is recorded on a fixed, non-transitory recording medium. The recording medium may be, but is not limited to, a semiconductor memory or a fixed magnetic disk device. This application claims priority based on Japanese Patent Application No. 2021-033113, filed on March 3, 2021, the disclosure of which is incorporated herein in its entirety. [Explanation of symbols]

[0070] 1. Optical submarine cable system 10. Communications equipment 20, 30 terminals 40-42 Repeater 50-53 Submarine Cable 100 Light control device 110 Tunable wavelength filter 120 Photoelectric conversion unit 130 Control Unit 140-143 Optical Coupler 150-152 Optical switch 200-202 Light control section 300, 310 Processing section 301 Optical Amplifier 302 Optical Equalizer

Claims

1. A wavelength tunable filter that can tune the transmission wavelength of input light; a photoelectric conversion means for converting the output light of the wavelength tunable filter into an electrical signal; a control unit that sets the transmission wavelength and outputs an instruction to control a communication device based on the electrical signal corresponding to the transmission wavelength, When the input light is a wavelength-multiplexed light of a control light and a signal light, the control means sets the transmission wavelength to the wavelength of the control light and controls the communication device based on the electrical signal. A light control device, a first optical coupler that branches the input light, guides one of the branched input light to the wavelength tunable filter, and guides the other of the branched input light to an optical path connected to an external device of the optical control device; a second optical coupler and a first optical switch; the first optical coupler connects the other branched input light to one input of the second optical coupler; the first optical switch outputs the output light of the wavelength tunable filter to either the other input of the second optical coupler or the photoelectric conversion means; the tunable filter outputs a response signal corresponding to the control light by controlling the transmission wavelength; the first optical switch outputs the response signal to the second optical coupler; the second optical coupler couples the output of the first optical switch with the other of the input light branched by the first optical coupler; Light control device.

2. A wavelength tunable filter that can tune the transmission wavelength of input light; a photoelectric conversion means for converting the output light of the wavelength tunable filter into an electrical signal; a control unit that sets the transmission wavelength and outputs an instruction to control a communication device based on the electrical signal corresponding to the transmission wavelength, When the input light is a wavelength-multiplexed light of a control light and a signal light, the control unit sets the transmission wavelength to the wavelength of the signal light and monitors the signal light based on the electrical signal. A light control device, a first optical coupler that branches the input light, guides one of the branched input light to the wavelength tunable filter, and guides the other of the branched input light to an optical path connected to an external device of the optical control device; a second optical coupler and a first optical switch; the first optical coupler connects the other branched input light to one input of the second optical coupler; the first optical switch outputs the output light of the wavelength tunable filter to either the other input of the second optical coupler or the photoelectric conversion means; the tunable filter outputs a response signal corresponding to the control light by controlling the transmission wavelength; the first optical switch outputs the response signal to the second optical coupler; the second optical coupler couples the output of the first optical switch with the other of the input light branched by the first optical coupler; Light control device.

3. the control unit controls the tunable filter to sweep the transmission wavelength, thereby obtaining a spectrum of at least one of the control light and the signal light.

3. The light control device according to claim 1 or 2.

4. a second optical switch that outputs one of the light input from the first optical coupler and the light input from another optical line to the wavelength-tunable filter; a third optical switch arranged between one of the outputs of the first optical switch and one of the inputs of the second optical coupler, and connecting one of the outputs of the first optical switch to one of the inputs of the second optical coupler and one of the other optical lines; The light control device according to any one of claims 1 to 3, comprising:

5. A repeater equipped with the light control device according to any one of claims 1 to 4, the control means controls the repeater as the communication device; Repeater.

6. The wavelength that transmits the input light is set in the tunable filter. converting the output light of the wavelength tunable filter into an electrical signal by a photoelectric conversion means; controlling a communication device based on the electrical signal corresponding to the transmission wavelength; When the input light is light in which control light and signal light are wavelength-multiplexed, the transmission wavelength is set to the wavelength of the control light, and the communication device is controlled based on the electrical signal. A control method for a light control device, comprising: the input light is split by a first optical coupler, one of the split input light is guided to the wavelength tunable filter, and the other of the split input light is connected to one of the inputs of a second optical coupler, thereby guiding the other to an optical path connected to an external device of the light control device; a first optical switch outputs the output light of the wavelength tunable filter to either the other input of the second optical coupler or the photoelectric conversion means; outputting a response signal corresponding to the control light by controlling the transmission wavelength using the tunable filter; outputting the response signal to the second optical coupler by the first optical switch; the second optical coupler couples the output of the first optical switch with the other of the input light branched by the first optical coupler; A method for controlling a light control device.

7. The wavelength that transmits the input light is set in the tunable filter. converting the output light of the wavelength tunable filter into an electrical signal by a photoelectric conversion means; controlling a communication device based on the electrical signal corresponding to the transmission wavelength; When the input light is a wavelength-multiplexed light of a control light and a signal light, the transmission wavelength is set to the wavelength of the signal light, and the signal light is monitored based on the electrical signal. A control method for a light control device, comprising: the input light is split by a first optical coupler, one of the split input light is guided to the wavelength tunable filter, and the other of the split input light is connected to one of the inputs of a second optical coupler, thereby guiding the other to an optical path connected to an external device of the light control device; a first optical switch outputs the output light of the wavelength tunable filter to either the other input of the second optical coupler or the photoelectric conversion means; outputting a response signal corresponding to the control light by controlling the transmission wavelength using the tunable filter; outputting the response signal to the second optical coupler by the first optical switch; the second optical coupler couples the output of the first optical switch with the other of the input light branched by the first optical coupler; A method for controlling a light control device.

Images