Wavelength multiplexing device and wavelength multiplexing method

Abstract

In an optical submarine cable system, the amount of work involved in setting up a terminal station device increases in association with an increase in volume. Thus, a wavelength multiplexing device according to the present invention comprises: a wavelength multiplexing means for causing input light inputted from a plurality of input ports for receiving optical signals to pass within a passband determined by a set center frequency and a set bandwidth, and outputting the light from an output port; an optical monitoring means for measuring optical power of the optical signals for each optical frequency and generating optical waveform information; a calculation means for calculating a main signal center frequency which is the center frequency of the optical signals and a main signal bandwidth which is the bandwidth of the optical signals; and a control means for setting the set center frequency to the main signal center frequency and setting the set bandwidth to the main signal bandwidth.

Description

[Technical field]

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

[0002] Optical submarine cable systems that connect continents with optical fibers play an important role as infrastructure supporting international communication networks. Optical submarine cable systems consist of submarine cables that accommodate optical fibers, submarine repeaters equipped with optical amplifiers, submarine branching equipment that branches optical signals, and terminal equipment installed at landing stations. The terminal equipment includes wavelength multiplexing equipment (WME), submarine line termination equipment (SLTE), and system monitoring equipment.

[0003] An example of such a terminal device used in an optical submarine cable system is described in Patent Document 1. The related terminal device described in Patent Document 1 includes a submarine line termination device SLTE and a monitoring system. The submarine line termination device SLTE includes a plurality of transponders TPD, a dummy light source, a multiplexing unit MUX, and an optical channel monitor OCM.

[0004] The multiplexing unit MUX and the optical channel monitor OCM receive transponder wavelength information (filter wavelength information) and dummy optical wavelength information from the monitoring system when the submarine line termination SLTE is started up and when a wavelength is added.

[0005] The multiplexing section MUX is a wavelength selective switch (WSS) with an active filter on the input side. The active filter is configured to be controlled to a filter shape that transmits signals according to transponder wavelength information from the monitoring system. In other words, when transponder wavelength information is received from the monitoring system, the active filter of the multiplexing section MUX is controlled to transmit signals. The optical channel monitor OCM also has an optical spectrum measurement function, which allows it to confirm the optical power measurement value of the wavelength slot that is the same as the specified wavelength received from the monitoring system.

[0006] That is, the associated terminal equipment is configured such that the optical channel monitor OCM acquires transponder wavelength information and dummy optical wavelength information from the monitoring system, and confirms the optical power measurement value of the wavelength slot that is the same as the designated wavelength received from the monitoring system.

[0007] With this configuration, the related terminal equipment can use the optical channel monitor OCM to detect the presence or absence of signals for each wavelength, thereby enabling good monitoring of the transmission path that transmits optical wavelength multiplexed signals.

[0008] Furthermore, a related technique is described in Patent Document 2. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] International Publication No. 2018 / 051935 [Patent Document 2] JP 2006-345372 A Summary of the Invention [Problem to be solved by the invention]

[0010] In an optical undersea cable system, communication is carried out by transmitting a wavelength-multiplexed optical signal, which is a multiplexed optical signal with different wavelengths, from a terminal device installed at a landing station. When installing or adding transponders that transmit and receive optical signals of each wavelength, it is necessary to set the filter characteristics of each input port of the wavelength multiplexing equipment (WME) into which the transponder is inserted, from a system monitoring device, as in the above-mentioned related terminal device.

[0011] For example, a current optical submarine cable system uses 16 fiber pairs, with 120 wavelengths multiplexed per fiber pair, so approximately 2,000 transponders are used per landing station. To set the filter characteristics of each input port of the wavelength division multiplexing equipment (WME), an operator must register the characteristics of the transmitted and received light (center frequency, bandwidth, etc.) of each transponder in the system monitoring device.

[0012] In recent years, with the increase in capacity of optical submarine cable systems, the number of fiber pairs has been increasing, and the number of transponders used has also been on the rise. This has resulted in an increase in the number of steps required to register the characteristics of each transponder.

[0013] Thus, in an optical submarine cable system, there has been a problem that the amount of setting work required in a terminal device increases as the capacity increases.

[0014] An object of the present invention is to provide a wavelength division multiplexing device and a wavelength division multiplexing method which solves the problem that the amount of setting work in a terminal device increases as the capacity increases in an optical submarine cable system. [Means for solving the problem]

[0015] The wavelength multiplexing device of the present invention comprises a wavelength multiplexing means for passing each input light input from a plurality of input ports that accept optical signals in a passband determined by a set center frequency and a set bandwidth, and outputting it from an output port, an optical monitoring means for measuring the optical power of the optical signal for each optical frequency and generating optical waveform information, a calculation means for calculating a main signal center frequency, which is the center frequency of the optical signal, and a main signal bandwidth, which is the bandwidth of the optical signal, from the optical waveform information, and a control means for setting the set center frequency to the main signal center frequency and the set bandwidth to the main signal bandwidth.

[0016] The wavelength multiplexing method of the present invention measures the optical power of an optical signal for each optical frequency to generate optical waveform information, calculates a main signal center frequency, which is the center frequency of the optical signal, and a main signal bandwidth, which is the bandwidth of the optical signal, from the optical waveform information, and when multiplexing the optical signal by passing it through a passband determined by the set center frequency and the set bandwidth, sets the set center frequency to the main signal center frequency and sets the set bandwidth to the main signal bandwidth. Effect of the Invention

[0017] According to the wavelength multiplexing device and the wavelength multiplexing method of the present invention, even if the capacity of the optical submarine cable system increases, it is possible to prevent an increase in the amount of setting work in the terminal equipment. [Brief description of the drawings]

[0018] [Figure 1] 1 is a block diagram showing a configuration of a wavelength multiplexer according to a first embodiment of the present invention. [Diagram 2] FIG. 5 is a block diagram showing a configuration of a wavelength multiplexer according to a second embodiment of the present invention. [Diagram 3] 11 is a diagram showing optical waveform information measured by an optical monitoring unit included in a wavelength multiplexer according to a second embodiment of the present invention. FIG. [Figure 4] FIG. 11 is a block diagram showing a configuration of a wavelength multiplexer according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0020] [First embodiment] 1 is a block diagram showing the configuration of a wavelength multiplexer 100 according to a first embodiment of the present invention. The wavelength multiplexer 100 has a wavelength multiplexing section (wavelength multiplexing means) 110, an optical monitoring section (optical monitoring means) 120, a calculation section (calculation means) 130, and a control section (control means) 140. The wavelength multiplexer 100 is preferably used in a terminal device constituting an optical submarine cable system.

[0021] The wavelength multiplexing unit 110 passes each input light input from a plurality of input ports that accept optical signals in a passband determined by a set center frequency and a set bandwidth, and outputs the input light from an output port. The optical monitoring unit 120 measures the optical power of the optical signal for each optical frequency to generate optical waveform information. The calculation unit 130 calculates the main signal center frequency, which is the center frequency of the optical signal, and the main signal bandwidth, which is the bandwidth of the optical signal, from this optical waveform information. Then, the control unit 140 sets the set center frequency to the main signal center frequency, and sets the set bandwidth to the main signal bandwidth.

[0022] As described above, in the wavelength multiplexer 100 according to the present embodiment, the calculation unit 130 calculates the main signal center frequency and main signal bandwidth of the optical signal from the optical waveform information measured and obtained by the optical monitoring unit 120. Then, the control unit 140 sets the passband of the wavelength multiplexer 110 based on the calculated main signal center frequency and main signal bandwidth. That is, the wavelength multiplexer 100 can automatically set the wavelength multiplexer 110. Therefore, simply by inserting (plugging in) a transponder into the input port of the wavelength multiplexer 110, the wavelength multiplexer 110 can be brought into a state in which an optical signal can be conducted, and the optical signal can be monitored.

[0023] Therefore, an operator does not need to register the characteristics (such as the center frequency and bandwidth of the optical signal to be transmitted and received) of the transponders connected to the wavelength multiplexing unit 110 in a system monitoring device, etc. As a result, the wavelength multiplexing device 100 according to this embodiment can avoid an increase in the amount of setting work in the terminal equipment even when the capacity of the optical submarine cable system increases.

[0024] The wavelength multiplexing unit 110 can typically be configured to include a wavelength selective switch (WSS). Here, by using a liquid crystal element such as LCOS (Liquid Crystal on Silicon) as the spatial light modulation element included in the wavelength selective switch (WSS), it becomes possible to change the passband. With such a configuration, the wavelength selective switch (WSS) can function as an active filter.

[0025] Typically, an optical channel monitor (OCM) can be used as the optical monitor unit 120. A known method of optical channel monitoring is to sweep an optical bandpass filter with a narrow frequency slot, convert it into an electrical signal by a photodetector, and measure the optical power at each optical frequency.

[0026] Next, the wavelength multiplexing method according to this embodiment will be described.

[0027] In the wavelength multiplexing method according to the present embodiment, first, the optical power of an optical signal is measured for each optical frequency to generate optical waveform information. Next, from this optical waveform information, a main signal center frequency, which is the center frequency of the optical signal, and a main signal bandwidth, which is the bandwidth of the optical signal, are calculated. Then, when multiplexing the optical signal by passing it through a passband determined by the set center frequency and the set bandwidth, the set center frequency is set to the main signal center frequency, and the set bandwidth is set to the main signal bandwidth.

[0028] In this way, in the wavelength multiplexing method according to the present embodiment, the main signal center frequency and main signal bandwidth of the optical signal are calculated from the measured optical waveform information, and the optical signal is passed through a pass band determined by the main signal center frequency and main signal bandwidth for multiplexing. Therefore, the pass band of the optical signal can be set automatically without the need for an operator to perform a registration operation.

[0029] As described above, according to the wavelength multiplexing device 100 and the wavelength multiplexing method of this embodiment, even if the capacity of the optical submarine cable system increases, it is possible to prevent an increase in the amount of setting work in the terminal equipment.

[0030] Second Embodiment Next, a second embodiment of the present invention will be described. Fig. 2 shows the configuration of a wavelength multiplexer 200 according to this embodiment. The wavelength multiplexer 200 has a wavelength multiplexing section (wavelength multiplexing means) 210, an optical monitoring section (optical monitoring means) 220, a calculation section (calculation means) 230, and a control section (control means) 240. The wavelength multiplexer 200 is preferably used in a terminal device constituting an optical submarine cable system.

[0031] The wavelength multiplexing unit 210 passes each input light input from a plurality of input ports 211 that accept optical signals in a passband determined by a set center frequency and a set bandwidth, and outputs the input light from an output port 212. The optical monitor unit 220 measures the optical power of the optical signal for each optical frequency to generate optical waveform information. The calculation unit 230 calculates the main signal center frequency, which is the center frequency of the optical signal, and the main signal bandwidth, which is the bandwidth of the optical signal, from this optical waveform information. Then, the control unit 240 sets the set center frequency to the main signal center frequency, and sets the set bandwidth to the main signal bandwidth.

[0032] The configuration up to this point is the same as that of the wavelength multiplexer 100 according to the first embodiment. The wavelength multiplexer 200 according to this embodiment further includes a photodetector (photodetection means) 250. Here, the photodetector 250 generates a photodetection signal when it detects an input of an optical signal.

[0033] Here, when the control unit 240 receives this light detection signal, it releases the restrictions on the set center frequency and set bandwidth, and expands the passband to the allowable range to the maximum passband. Specifically, for example, for the input port where the light detection unit 250 detects the input of the optical signal, the active filter of the wavelength selective switch (WSS) included in the wavelength multiplexing unit 210 is set to a fully open state. This allows the optical signal to pass through the wavelength multiplexing unit 210 and reach the optical monitoring unit 220 even before the passband of the wavelength multiplexing unit 210 is set to a predetermined band determined by the characteristics of the optical signal.

[0034] The optical monitoring section 220 generates first optical waveform information, which is optical waveform information, from the optical signal that has passed through the wavelength multiplexing section 210 in the maximum passband.

[0035] In this case, the calculation section 230 calculates a first main signal center frequency and a first main signal bandwidth from the first optical waveform information, and the control section 240 can be configured to set the set center frequency to the first main signal center frequency and the set bandwidth to the first main signal bandwidth.

[0036] With this configuration, the wavelength multiplexing device 200 can automatically configure the wavelength multiplexing unit 210 without relying on an operator's registration work. Therefore, simply by inserting (plugging in) a transponder into the input port of the wavelength multiplexing unit 210, the wavelength multiplexing unit 210 can be brought into a state in which an optical signal can be conducted, and the optical signal can be monitored.

[0037] Next, the operation of the calculation unit 230 will be described in further detail.

[0038] 3 shows an example of optical waveform information (first optical waveform information) measured by optical monitor 220. Optical monitor 120 is typically an optical channel monitor (OCM), which sweeps an optical bandpass filter with a narrow frequency slot (e.g., 6.25 GHz width), converts it into an electrical signal by a photodetector, and measures the optical power at each optical frequency.

[0039] The calculation unit 230 derives the rising frequency F1 and the falling frequency F2 in the optical waveform (spectrum waveform) WF of the optical signal from this optical waveform information, and calculates the main signal center frequency FC and the main signal bandwidth from the rising frequency F1 and the falling frequency F2. Specifically, for example, when the absolute value of the difference in optical power between adjacent frequency slots exceeds a predetermined threshold, the calculation unit 230 determines that the optical frequency in this frequency slot is the rising frequency F1 or the falling frequency F2. Such a function of the calculation unit 230 can be realized by firmware, and can be implemented using, for example, an FPGA (Field Programmable Gate Array) or the like.

[0040] Next, the wavelength multiplexing method according to this embodiment will be described.

[0041] In the wavelength multiplexing method according to the present embodiment, first, the optical power of an optical signal is measured for each optical frequency to generate optical waveform information. Next, from this optical waveform information, a main signal center frequency, which is the center frequency of the optical signal, and a main signal bandwidth, which is the bandwidth of the optical signal, are calculated. Then, when multiplexing the optical signal by passing it through a passband determined by the set center frequency and the set bandwidth, the set center frequency is set to the main signal center frequency, and the set bandwidth is set to the main signal bandwidth.

[0042] The configuration up to this point is the same as the wavelength multiplexing method in the first embodiment. The wavelength multiplexing method according to this embodiment is further configured to generate a photodetection signal when an input of an optical signal is detected, and when this photodetection signal is received, the limitations of the set center frequency and set bandwidth are lifted to expand the passband to the allowable range to the maximum passband. Here, generating the above-mentioned optical waveform information includes generating first optical waveform information, which is optical waveform information, from an optical signal that has passed through the maximum passband.

[0043] In this case, calculating the main signal center frequency and the main signal bandwidth described above may include calculating a first main signal center frequency that is the main signal center frequency and a first main signal bandwidth that is the main signal bandwidth from the first optical waveform information. Also, setting the set center frequency as the main signal center frequency described above may include setting the set center frequency to the first main signal center frequency. Similarly, setting the set bandwidth as the main signal bandwidth described above may include setting the set bandwidth to the first main signal bandwidth.

[0044] Furthermore, calculating the main signal center frequency and the main signal bandwidth described above may include deriving a rise frequency and a fall frequency in the optical waveform of the optical signal from the optical waveform information, and may include calculating the main signal center frequency and the main signal bandwidth from the rise frequency and the fall frequency.

[0045] As described above, according to the wavelength multiplexing device 200 and the wavelength multiplexing method of this embodiment, even if the capacity of the optical submarine cable system increases, it is possible to prevent an increase in the amount of setting work in the terminal equipment.

[0046] Third embodiment Next, a third embodiment of the present invention will be described. Fig. 4 shows the configuration of a wavelength multiplexer 300 according to this embodiment. The wavelength multiplexer 300 has a wavelength multiplexing section (wavelength multiplexing means) 310, an optical monitoring section (optical monitoring means) 320, a calculation section (calculation means) 330, and a control section (control means) 340. The wavelength multiplexer 300 is preferably used in a terminal device constituting an optical submarine cable system.

[0047] The wavelength multiplexing unit 310 passes each input light input from a plurality of input ports 311 that accept optical signals in a passband determined by a set center frequency and a set bandwidth, and outputs the input light from an output port 312. The optical monitor unit 320 measures the optical power of the optical signal for each optical frequency to generate optical waveform information. The calculation unit 330 calculates the main signal center frequency, which is the center frequency of the optical signal, and the main signal bandwidth, which is the bandwidth of the optical signal, from this optical waveform information. Then, the control unit 340 sets the set center frequency to the main signal center frequency, and sets the set bandwidth to the main signal bandwidth.

[0048] The configuration up to this point is the same as that of the wavelength multiplexer 100 according to the first embodiment. The wavelength multiplexer 300 according to this embodiment further includes a light detection section (light detection means) 350 and an optical switch section (optical switch means) 360.

[0049] The optical detector 350 generates an optical detection signal when it detects an input of an optical signal. The optical switch 360 switches the optical path of the optical signal between a first optical path 361 toward the wavelength multiplexer 310 and a second optical path 362 toward the optical monitor 320. Here, when the optical switch 360 receives an optical detection signal, it switches the optical path from the first optical path 361 to the second optical path 362. This allows the optical signal to reach the optical monitor 320 even before the passband of the wavelength multiplexer 310 is set to a predetermined band determined by the characteristics of the optical signal.

[0050] The optical monitoring section 320 generates second optical waveform information, which is optical waveform information, from the optical signal that has passed through the second optical path 362 .

[0051] In this case, the calculation unit 330 calculates a second main signal center frequency, which is the main signal center frequency, and a second main signal bandwidth, which is the main signal bandwidth, from this second optical waveform information. Then, the control unit 340 sets the set center frequency to the second main signal center frequency and sets the set bandwidth to the second main signal bandwidth. After this, that is, after the set center frequency is set to the second main signal center frequency and the set bandwidth is set to the second main signal bandwidth, the optical switch unit 360 switches the optical path from the second optical path 362 to the first optical path 361.

[0052] With this configuration, the wavelength multiplexing device 300 can automatically configure the wavelength multiplexing unit 310 without relying on an operator's registration work. Therefore, simply by inserting (plugging in) a transponder into the input port of the wavelength multiplexing unit 310, the wavelength multiplexing unit 310 can be brought into a state in which an optical signal can be conducted, and the optical signal can be monitored.

[0053] The calculation unit 330 included in the wavelength multiplexer 300 of this embodiment also performs the same operation as the calculation unit 230 according to the second embodiment. That is, as described with reference to FIG. 3, the calculation unit 330 derives the rising frequency F1 and the falling frequency F2 in the optical waveform WF of the optical signal from the optical waveform information measured by the optical monitor 320. Then, the calculation unit 330 calculates the main signal center frequency FC and the main signal bandwidth from the rising frequency F1 and the falling frequency F2. Specifically, for example, when the absolute value of the difference in optical power between adjacent frequency slots exceeds a predetermined threshold, the calculation unit 330 determines that the optical frequency in this frequency slot is the rising frequency F1 or the falling frequency F2.

[0054] Next, the wavelength multiplexing method according to this embodiment will be described.

[0055] In the wavelength multiplexing method according to the present embodiment, first, the optical power of an optical signal is measured for each optical frequency to generate optical waveform information. Next, from this optical waveform information, a main signal center frequency, which is the center frequency of the optical signal, and a main signal bandwidth, which is the bandwidth of the optical signal, are calculated. Then, when multiplexing the optical signal by passing it through a passband determined by the set center frequency and the set bandwidth, the set center frequency is set to the main signal center frequency, and the set bandwidth is set to the main signal bandwidth.

[0056] The configuration up to this point is the same as that of the wavelength multiplexing method in the first embodiment. The wavelength multiplexing method according to this embodiment is further configured to generate a photodetection signal when an input of an optical signal is detected, and to switch the optical path of the optical signal between a first optical path that passes the optical signal in a passband and a second optical path different from the first optical path. Here, the switching of the optical path described above includes switching the optical path from the first optical path to the second optical path when a photodetection signal is received. In addition, the generating of the optical waveform information described above includes generating second optical waveform information, which is optical waveform information, from the optical signal that has passed through the second optical path.

[0057] In this case, calculating the main signal center frequency and the main signal bandwidth described above may include calculating a second main signal center frequency that is the main signal center frequency and a second main signal bandwidth that is the main signal bandwidth from the second optical waveform information. Also, setting the set center frequency as the main signal center frequency described above may include setting the set center frequency to the second main signal center frequency. Similarly, setting the set bandwidth as the main signal bandwidth described above may include setting the set bandwidth to the second main signal bandwidth.

[0058] Furthermore, switching the optical path described above may include switching the optical path from the second optical path to the first optical path after setting the set center frequency to the second main signal center frequency and setting the set bandwidth to the second main signal bandwidth.

[0059] Furthermore, calculating the main signal center frequency and the main signal bandwidth described above may include deriving a rise frequency and a fall frequency in the optical waveform of the optical signal from the optical waveform information, and may include calculating the main signal center frequency and the main signal bandwidth from the rise frequency and the fall frequency.

[0060] As described above, according to the wavelength multiplexing device 300 and the wavelength multiplexing method of this embodiment, even if the capacity of the optical submarine cable system increases, it is possible to prevent an increase in the amount of setting work in the terminal equipment.

[0061] A part or all of the above-described embodiments can be described as, but is not limited to, the following supplementary notes.

[0062] (Supplementary Note 1) A wavelength multiplexing device comprising: wavelength multiplexing means for passing each input light input from a plurality of input ports that accept optical signals in a passband determined by a set center frequency and a set bandwidth, and outputting the same from an output port; optical monitoring means for measuring the optical power of the optical signal for each optical frequency to generate optical waveform information; calculation means for calculating a main signal center frequency that is the center frequency of the optical signal and a main signal bandwidth that is the bandwidth of the optical signal from the optical waveform information; and control means for setting the set center frequency to the main signal center frequency and for setting the set bandwidth to the main signal bandwidth.

[0063] (Appendix 2) A wavelength multiplexing device as described in Appendix 1, further comprising a photodetection means for generating a photodetection signal when it detects input of the optical signal, wherein the control means, upon receiving the photodetection signal, removes the limitations on the set center frequency and the set bandwidth to set the passband to a maximum passband expanded to an allowable range, and the optical monitor means generates first optical waveform information, which is the optical waveform information, from the optical signal that has passed through the wavelength multiplexing means in the maximum passband.

[0064] (Supplementary Note 3) A wavelength multiplexing device as described in Supplementary Note 2, wherein the calculation means calculates a first main signal center frequency that is the main signal center frequency and a first main signal bandwidth that is the main signal bandwidth from the first optical waveform information, and the control means sets the set center frequency to the first main signal center frequency and sets the set bandwidth to the first main signal bandwidth.

[0065] (Supplementary Note 4) A wavelength multiplexing device as described in Supplementary Note 1, further comprising: optical detection means for generating an optical detection signal when detecting an input of the optical signal; and optical switch means for switching an optical path of the optical signal between a first optical path toward the wavelength multiplexing means and a second optical path toward the optical monitor means, wherein the optical switch means switches the optical path from the first optical path to the second optical path when it receives the optical detection signal, and the optical monitor means generates second optical waveform information, which is the optical waveform information, from the optical signal that has passed through the second optical path.

[0066] (Supplementary Note 5) The wavelength multiplexing device according to Supplementary Note 4, wherein the calculation means calculates a second main signal center frequency that is the main signal center frequency and a second main signal bandwidth that is the main signal bandwidth from the second optical waveform information, the control means sets the set center frequency to the second main signal center frequency and sets the set bandwidth to the second main signal bandwidth, and the optical switch means switches the optical path from the second optical path to the first optical path after the set center frequency is set to the second main signal center frequency and the set bandwidth is set to the second main signal bandwidth.

[0067] (Supplementary Note 6) A wavelength multiplexing device according to any one of Supplementary Notes 1 to 5, wherein the calculation means derives a rise frequency and a fall frequency in an optical waveform of the optical signal from the optical waveform information, and calculates the main signal center frequency and the main signal bandwidth from the rise frequency and the fall frequency.

[0068] (Supplementary Note 7) A wavelength multiplexing device according to any one of Supplementary Notes 1 to 6, wherein the wavelength multiplexing means has a wavelength selection switch equipped with a spatial light modulation element made of a liquid crystal element.

[0069] (Appendix 8) A wavelength multiplexing method in which the optical power of an optical signal is measured for each optical frequency to generate optical waveform information, a main signal center frequency which is the center frequency of the optical signal and a main signal bandwidth which is the bandwidth of the optical signal are calculated from the optical waveform information, and when multiplexing the optical signal by passing it through a passband determined by the set center frequency and the set bandwidth, the set center frequency is set to the main signal center frequency and the set bandwidth is set to the main signal bandwidth.

[0070] (Appendix 9) The wavelength multiplexing method according to appendix 8, wherein generating an optical detection signal when detecting input of the optical signal, and, when receiving the optical detection signal, removing the limitations on the set center frequency and the set bandwidth to set the passband to a maximum passband expanded to an allowable range, and generating the optical waveform information includes generating first optical waveform information, which is the optical waveform information, from the optical signal that has passed through the maximum passband.

[0071] (Supplementary Note 10) The wavelength multiplexing method according to Supplementary Note 9, wherein calculating the main signal center frequency and the main signal bandwidth includes calculating a first main signal center frequency that is the main signal center frequency and a first main signal bandwidth that is the main signal bandwidth from the first optical waveform information, setting the set center frequency to the main signal center frequency includes setting the set center frequency to the first main signal center frequency, and setting the set bandwidth to the main signal bandwidth includes setting the set bandwidth to the first main signal bandwidth.

[0072] (Supplementary Note 11) A wavelength multiplexing method as described in Supplementary Note 8, further comprising generating an optical detection signal when detecting an input of the optical signal, and switching an optical path of the optical signal between a first optical path that passes the optical signal in the pass band and a second optical path different from the first optical path, wherein switching the optical path includes switching the optical path from the first optical path to the second optical path when the optical detection signal is received, and generating the optical waveform information includes generating second optical waveform information, which is the optical waveform information, from the optical signal that has passed through the second optical path.

[0073] (Supplementary Note 12) The wavelength multiplexing method according to Supplementary Note 11, wherein calculating the main signal center frequency and the main signal bandwidth includes calculating a second main signal center frequency that is the main signal center frequency and a second main signal bandwidth that is the main signal bandwidth from the second optical waveform information, setting the set center frequency to the main signal center frequency includes setting the set center frequency to the second main signal center frequency, setting the set bandwidth to the main signal bandwidth includes setting the set bandwidth to the second main signal bandwidth, and switching the optical path includes switching the optical path from the second optical path to the first optical path after setting the set center frequency to the second main signal center frequency and setting the set bandwidth to the second main signal bandwidth.

[0074] (Supplementary Note 13) The wavelength multiplexing method according to any one of Supplementary Notes 8 to 12, wherein calculating the main signal center frequency and the main signal bandwidth includes deriving a rise frequency and a fall frequency in an optical waveform of the optical signal from the optical waveform information, and calculating the main signal center frequency and the main signal bandwidth from the rise frequency and the fall frequency.

[0075] Although the present invention has been described above with reference to the embodiment, the present invention is not limited to the above embodiment. 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. [Explanation of symbols]

[0076] 100, 200, 300 wavelength multiplexer 110, 210, 310 wavelength multiplexer 120, 220, 320 Optical monitor section 130, 230, 330 calculation section 140, 240, 340 Control unit 211, 311 input ports 212, 312 output ports 250, 350 Light detection unit 360 Optical switch section 361 First Light Path 362 Second Light Path

Claims

1. A wavelength multiplexing means for passing each input light inputted from a plurality of input ports for receiving optical signals in a passband determined by a set center frequency and a set bandwidth, and outputting the same from an output port; an optical monitor means for measuring the optical power of the optical signal for each optical frequency and generating optical waveform information; a calculation means for calculating a main signal center frequency, which is a center frequency of the optical signal, and a main signal bandwidth, which is a bandwidth of the optical signal, from the optical waveform information; a control means for setting the set center frequency to the main signal center frequency and the set bandwidth to the main signal bandwidth; a light detection means for generating a light detection signal when the light signal input is detected, when the control means receives the light detection signal, the control means releases the limitations of the set center frequency and the set bandwidth to expand the passband to a tolerable range and sets the passband to a maximum passband; The optical monitor means generates first optical waveform information, which is the optical waveform information, from the optical signal that has passed through the wavelength multiplexing means in the maximum passband. Wavelength multiplexing device.

2. The calculation means calculates a first main signal center frequency that is the main signal center frequency and a first main signal bandwidth that is the main signal bandwidth from the first optical waveform information, The control means sets the set center frequency to the first main signal center frequency and sets the set bandwidth to the first main signal bandwidth.

2. A wavelength division multiplexing device according to claim 1.

3. A wavelength multiplexing means for passing each input light inputted from a plurality of input ports for receiving optical signals in a passband determined by a set center frequency and a set bandwidth, and outputting the same from an output port; an optical monitor means for measuring the optical power of the optical signal for each optical frequency and generating optical waveform information; a calculation means for calculating a main signal center frequency, which is a center frequency of the optical signal, and a main signal bandwidth, which is a bandwidth of the optical signal, from the optical waveform information; a control means for setting the set center frequency to the main signal center frequency and the set bandwidth to the main signal bandwidth; a light detection means for generating a light detection signal when the light signal input is detected; an optical switch means for switching an optical path of the optical signal between a first optical path toward the wavelength multiplexing means and a second optical path toward the optical monitor means; the optical switch means switches the optical path from the first optical path to the second optical path when the optical detection signal is received; The optical monitoring means generates second optical waveform information, which is the optical waveform information, from the optical signal that has passed through the second optical path. Wavelength multiplexing device.

4. The calculation means calculates a second main signal center frequency that is the main signal center frequency and a second main signal bandwidth that is the main signal bandwidth from the second optical waveform information, the control means sets the set center frequency to the second main signal center frequency and sets the set bandwidth to the second main signal bandwidth; The optical switch means switches the optical path from the second optical path to the first optical path after the set center frequency is set to the second main signal center frequency and the set bandwidth is set to the second main signal bandwidth.

4. A wavelength division multiplexing device according to claim 3.

5. The calculation means derives a rise frequency and a fall frequency in an optical waveform of the optical signal from the optical waveform information, and calculates the main signal center frequency and the main signal bandwidth from the rise frequency and the fall frequency.

5. A wavelength division multiplexing device according to claim 1.

6. The wavelength multiplexing means has a wavelength selection switch equipped with a spatial light modulation element made of a liquid crystal element.

6. A wavelength division multiplexing device according to claim 1.

7. A method for generating optical waveform information by measuring the optical power of an optical signal for each optical frequency, Calculating a main signal center frequency, which is a center frequency of the optical signal, and a main signal bandwidth, which is a bandwidth of the optical signal, from the optical waveform information; When the optical signals are multiplexed by passing them through a passband determined by a set center frequency and a set bandwidth, the set center frequency is set to the main signal center frequency, and the set bandwidth is set to the main signal bandwidth; generating a light detection signal when the input of the optical signal is detected; When the light detection signal is received, the limitations of the set center frequency and the set bandwidth are lifted to expand the passband to a maximum passband within an allowable range. A wavelength multiplexing method, comprising: Generating the optical waveform information includes generating first optical waveform information, which is the optical waveform information, from the optical signal that has passed through the maximum passband. Wavelength multiplexing method.

8. Calculating the main signal center frequency and the main signal bandwidth includes calculating a first main signal center frequency that is the main signal center frequency and a first main signal bandwidth that is the main signal bandwidth from the first optical waveform information; setting the set center frequency to the main signal center frequency includes setting the set center frequency to the first main signal center frequency; Setting the set bandwidth to the main signal bandwidth includes setting the set bandwidth to the first main signal bandwidth.

8. A wavelength multiplexing method according to claim 7.

9. A method for generating optical waveform information by measuring the optical power of an optical signal for each optical frequency, Calculating a main signal center frequency, which is a center frequency of the optical signal, and a main signal bandwidth, which is a bandwidth of the optical signal, from the optical waveform information; When the optical signals are multiplexed by passing them through a passband determined by a set center frequency and a set bandwidth, the set center frequency is set to the main signal center frequency, and the set bandwidth is set to the main signal bandwidth; generating a light detection signal when the input of the optical signal is detected; An optical path of the optical signal is switched between a first optical path that passes the optical signal in the passband and a second optical path different from the first optical path. A wavelength multiplexing method, comprising: switching the optical path includes switching the optical path from the first optical path to the second optical path when the optical detection signal is received; Generating the optical waveform information includes generating second optical waveform information, which is the optical waveform information, from the optical signal that has passed through the second optical path. Wavelength multiplexing method.

10. Calculating the main signal center frequency and the main signal bandwidth includes calculating a second main signal center frequency that is the main signal center frequency and a second main signal bandwidth that is the main signal bandwidth from the second optical waveform information; setting the set center frequency to the main signal center frequency includes setting the set center frequency to the second main signal center frequency; setting the set bandwidth to the main signal bandwidth includes setting the set bandwidth to the second main signal bandwidth; Switching the optical path includes setting the set center frequency to the second main signal center frequency and setting the set bandwidth to the second main signal bandwidth, and then switching the optical path from the second optical path to the first optical path.

10. A wavelength multiplexing method according to claim 9.

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