Optical transmission device, terminal device, optical communication system and optical communication method

Abstract

The purpose is to flexibly control the dummy light included in the wavelength multiplexed optical signal and suppress the degradation of the signal quality. The optical signal adjustment unit (1) is configured so that a plurality of optical signals with different wavelengths are input thereto, and the intensity of each of the plurality of optical signals is adjusted based on the intensity change in the transmission line, and the optical signal is output. The dummy light output unit (2) outputs a plurality of dummy lights (D) with different wavelengths, each dummy light having an intensity based on the intensity change in the transmission line; the control unit (4) confirms the dummy light corresponding to each of the optical signals, and controls the intensity of the confirmed dummy light based on the intensity of the optical signal corresponding to the confirmed dummy light and output from the optical signal adjustment unit (1). The multiplexing unit (3) outputs the wavelength multiplexed optical signal (L), wherein the dummy light (D) is combined with the optical signal (L10) output from the optical signal adjustment unit.

Description

Technical Field

[0001] The present invention relates to an optical transmission device, a terminal device, an optical communication system and an optical communication method. Background Art

[0002] In a submarine optical cable system, an optical transmission device installed in a land terminal station transmits a wavelength-multiplexed optical signal through a submarine optical cable. In order to compensate for the optical loss caused by the transmission through the submarine optical cable, a plurality of optical amplifiers are usually inserted into the submarine optical cable. Each optical amplifier amplifies the input wavelength-multiplexed optical signal to a certain intensity and outputs the amplified signal. Therefore, when a wavelength-multiplexed optical signal is amplified while blocking one of the wavelengths included therein, for example, the intensity of the other wavelengths is significantly increased. The increase in the intensity of the optical signal will cause the signal quality to deteriorate due to nonlinear effects, so one technique is to suppress the intensity change of each wavelength of the wavelength-multiplexed optical signal by, for example, adding a dummy light corresponding to the blocked wavelength when blocking one of the wavelengths in the wavelength-multiplexed optical signal.

[0003] As a technology using dummy light, an optical transmission device (optical transmission device) using a single wideband (bandwidth) dummy light or multiple narrowband (channel width) dummy lights for each sub-band is proposed. When a new optical signal is inserted into a sub-band using multiple narrowband dummy lights, the optical transmission device adjusts the intensity of the multiple dummy lights in the sub-band, thereby keeping the intensity of the wavelength multiplexed optical signal constant.

[0004] [Citation List]

[0005] Patent Literature

[0006] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2014-187671 Summary of the invention

[0007] [Technical issues]

[0008] The gain of an optical amplifier inserted into a submarine optical cable and the optical loss caused by transmitting an optical signal through the submarine optical cable vary depending on the wavelength, and therefore have wavelength dependence. Thus, when a wavelength-multiplexed optical signal in which optical signals have different wavelengths and have the same intensity is transmitted through a submarine optical cable, for example, the intensity becomes different depending on the wavelength. The intensity difference of the optical signal thus generated causes nonlinear effects and degradation of the signal-to-noise ratio. One way to suppress the nonlinear effects and degradation of the signal-to-noise ratio is to apply an intensity difference (pre-emphasis) for each wavelength to the wavelength-multiplexed optical signal based on inverse wavelength dependence, which cancels the wavelength dependence that occurs in the wavelength-multiplexed optical signal due to transmission, and then output the wavelength-multiplexed optical signal to the submarine optical cable.

[0009] However, in Patent Document 1, when adjusting the intensity of dummy light, the dummy light whose intensity is to be adjusted is not identified among a plurality of narrowband dummy lights. Therefore, when a new optical signal is inserted, the wavelength multiplexed optical signal does not have inverse wavelength dependence that cancels the wavelength dependence of the submarine optical cable after the new optical signal is inserted. As a result, the degradation of signal quality based on wavelength dependence in the submarine optical cable cannot be properly suppressed.

[0010] The present invention has been made in view of the above circumstances, and an object of the present invention is to flexibly control dummy light included in a wavelength multiplexed optical signal and suppress degradation of signal quality.

[0011] [Problem Solution]

[0012] According to one aspect of the present invention, the optical transmission device includes: an optical signal adjustment unit, which is configured to receive an input of a plurality of optical signals having different wavelengths, adjust the intensity of each of the plurality of optical signals based on an intensity variation in a transmission line, and output an optical signal; a dummy light output unit, which is configured to output a plurality of dummy lights having different wavelengths, each dummy light having an intensity based on an intensity variation in the transmission line; a control unit, which is configured to confirm a dummy light corresponding to each of the optical signals, and control the intensity of the confirmed dummy light based on the intensity of the optical signal corresponding to the confirmed dummy light and output from the optical signal adjustment unit; and a multiplexing unit, which is configured to combine the dummy light with the optical signal output from the optical signal adjustment unit to output a wavelength-multiplexed optical signal.

[0013] According to one aspect of the present invention, the terminal device includes: one or more optical transceivers; and an optical transmission device, which is configured to receive inputs of multiple optical signals with different wavelengths from the one or more optical transceivers, wherein the optical transmission device includes: an optical signal adjustment unit, which is configured to be able to receive inputs of multiple optical signals, adjust the intensity of each of the multiple optical signals based on the intensity change in the transmission line, and output the optical signal; a dummy light output unit, which is configured to output multiple dummy lights with different wavelengths, each dummy light having an intensity based on the intensity change in the transmission line; a control unit, which is configured to confirm the dummy light corresponding to each optical signal in the optical signal, and control the intensity of the confirmed dummy light based on the intensity of the optical signal corresponding to the confirmed dummy light and output from the optical signal adjustment unit; and a multiplexing unit, which is configured to combine the dummy light with the optical signal output from the optical signal adjustment unit to output a wavelength-multiplexed optical signal.

[0014] The optical communication system according to one aspect of the present invention comprises: a first terminal station, which is configured to output a wavelength multiplexed optical signal; and a second terminal station, which is configured to receive the wavelength multiplexed optical signal, wherein the first terminal station comprises: one or more optical transceivers; and an optical transmission device, which is configured to receive an input of a plurality of optical signals having different wavelengths from the one or more optical transceivers, and the optical transmission device comprises: an optical signal adjustment unit, which is configured to be able to receive an input of a plurality of optical signals, and adjust the plurality of optical signals based on intensity changes in the transmission line. The optical signal adjusting unit includes a first optical signal adjusting unit and a second optical signal adjusting unit. The first optical signal adjusting unit includes a first optical signal adjusting unit and a second optical signal adjusting unit. The first optical signal adjusting unit includes a first optical signal adjusting unit and a second optical signal adjusting unit. The first optical signal adjusting unit includes a first optical signal adjusting unit and a second optical signal adjusting unit. The first optical signal adjusting unit includes a first optical signal adjusting unit and a second optical signal adjusting unit. The first optical signal adjusting unit includes a first optical signal adjusting unit and a second optical signal adjusting unit. The first optical signal adjusting unit includes a first optical signal adjusting unit and a second optical signal adjusting unit. The first optical signal adjusting unit includes a first optical signal adjusting unit and a second optical signal adjusting unit. The first optical signal adjusting unit includes a first optical signal adjusting unit and a second optical signal adjusting unit. The first optical signal adjusting unit includes a first optical signal adjusting unit and a second optical signal adjusting unit. The first optical signal adjusting unit includes a first optical signal adjusting unit and a second optical signal adjusting unit.

[0015] According to one aspect of the present invention, the optical communication method includes: adjusting the intensity of each of a plurality of optical signals having different wavelengths based on intensity variations in a transmission line, and outputting an optical signal; outputting a plurality of dummy lights having different wavelengths, each dummy light having an intensity based on intensity variations in the transmission line; confirming a dummy light corresponding to each of the optical signals, and controlling the intensity of the confirmed dummy light based on the intensity of the optical signal based on the intensity variations in the transmission line corresponding to the confirmed dummy light; and outputting a wavelength multiplexed optical signal, wherein the dummy light is combined with the optical signal of the adjusted intensity.

[0016] Advantageous Effects of the Invention

[0017] The present invention allows flexible control of dummy light included in a wavelength multiplexed optical signal and suppresses degradation of signal quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a view showing a basic configuration of an optical communication system including an optical transmission device according to a first exemplary embodiment;

[0019] Figure 2 is a view schematically showing a configuration of a terminal station according to a first exemplary embodiment;

[0020] Figure 3is a diagram showing intensity changes of a wavelength multiplexed optical signal before and after transmission without applying pre-emphasis;

[0021] Figure 4 is a diagram showing intensity changes of a wavelength multiplexed optical signal before and after transmission with pre-emphasis applied;

[0022] Figure 5 is a view schematically showing a plurality of dummy lights and cover bands corresponding thereto;

[0023] Figure 6 is a diagram showing a relationship between the intensity of dummy light and a target value of an optical signal;

[0024] Figure 7 is a view schematically showing a configuration of an optical transmission device according to a first exemplary embodiment;

[0025] Figure 8 is a flowchart showing the operation of the optical transmission device in the case where a new optical signal is added;

[0026] Fig. 9 is a view schematically showing an example of connecting a new optical transceiver to a terminal station according to the first exemplary embodiment;

[0027] Fig.10 is a view schematically showing an example in which a new optical signal is input to an optical transmission device of a terminal station according to the first exemplary embodiment;

[0028] Fig.11 is a flow chart showing the operation of the optical transmission device in the case where the optical signal is eliminated from the cover band;

[0029] Fig.12 is a diagram showing a virtual light intensity in a case where an optical signal is eliminated;

[0030] Fig.13 is a view schematically showing a configuration of an optical transmission device of a second exemplary embodiment;

[0031] Fig.14 is a flowchart showing the operation of the optical transmission device in the case where a new optical signal is inserted;

[0032] Fig.15 is a flowchart showing the operation of the optical transmission device in the case where an optical signal is eliminated from a wavelength multiplexed optical signal;

[0033] Fig.16 is a flowchart showing an operation in the case where a new optical signal is added to the optical transmission apparatus according to the third exemplary embodiment;

[0034] Fig.17is a diagram showing a situation where an optical signal overlaps a band occupied by dummy light;

[0035] Fig.18 is a diagram showing an optical signal and dummy light in a case where the compensation function of the dummy light in the cover strip is performed by an adjacent cover strip instead;

[0036] Fig.19 is a diagram showing an optical signal and dummy light in a case where two adjacent cover strips alternately perform a compensation function of the dummy light in the cover strip;

[0037] Fig. 20 is a flowchart showing an operation in the case where a new optical signal is added to the optical transmission apparatus according to the fourth exemplary embodiment;

[0038] Fig.21 is a view showing a case where an optical signal overlaps two cover bands;

[0039] Fig. 22 is a diagram showing an optical signal and dummy light in a case where the compensation function of the dummy light in a cover strip is distributed between dummy lights in two cover strips;

[0040] Fig.23 is a view showing a second example of a dummy light and a cover band corresponding thereto;

[0041] Fig.24 is a view showing a third example of a dummy light and a cover band corresponding thereto;

[0042] Fig.25 is a view showing a fourth example of dummy light and a cover band corresponding thereto; and

[0043] Fig.26 is a view showing a fifth example of dummy light and a cover tape corresponding thereto. DETAILED DESCRIPTION

[0044] Hereinafter, exemplary embodiments of the present invention will be described in conjunction with the accompanying drawings. In the accompanying drawings, the same reference numerals represent the same structural elements, and redundant descriptions are omitted as appropriate.

[0045] First exemplary embodiment

[0046] The following describes an optical transmission device 100 according to a first exemplary embodiment. Figure 1 A basic configuration of an optical communication system 1000 including the optical transmission device 100 according to the first exemplary embodiment is shown. The following description assumes that the optical transmission device 100 is installed in a land terminal station included in the optical communication system 1000 constituting a submarine optical network.

[0047] Figure 1The configuration example of the optical communication system 1000 according to the first exemplary embodiment is schematically shown. In this example, the optical communication system 1000 includes terminal stations TS1 and TS2, an optical amplifier AMP, an optical fiber F, and a management server 1001. The terminal stations TS1 and TS2 are terminal stations installed on land. The terminal station TS1 includes an optical transmission device 100.

[0048] The management server 1001 is configured to be able to control the operations of the terminal station TS1 and the optical transmission device 100 by providing an instruction signal INS.

[0049] The terminal station TS1 is connected to the terminal station TS2 by a transmission line installed on land or on the seabed, and includes an optical fiber F for transmitting an optical signal. In this example, the transmission line for transmitting an optical signal from the terminal station TS1 (first terminal station) to the terminal station TS2 (second terminal station) is referred to as a transmission line TL1. The transmission line for transmitting an optical signal from the terminal station TS2 to the terminal station TS1 is referred to as a transmission line TL2. Note that another device such as a submarine optical branching device for increasing or decreasing an optical signal may be inserted into the transmission lines TL1 and TL2 as needed.

[0050] One or more optical amplifiers AMP that amplify optical signals are inserted in each of the transmission lines TL1 and TL2.

[0051] In this exemplary embodiment, a wavelength multiplexed optical signal L (first wavelength multiplexed optical signal) is output from the terminal station TS1 to the terminal station TS2 through the transmission line TL1. In the wavelength multiplexed optical signal L, optical signals having one or more wavelengths (channels) to be transmitted are wavelength multiplexed. A wavelength multiplexed optical signal LL (second wavelength multiplexed optical signal) is output from the terminal station TS2 to the terminal station TS1 through the transmission line TL2.

[0052] The following describes the configuration of the terminal station TS1 according to this exemplary embodiment. Like a general terminal station, the terminal station TS1 includes an optical transmission device and a plurality of optical transceivers. Figure 2 The configuration of the terminal station TS1 according to the first exemplary embodiment is schematically shown. Figure 2 As shown, the terminal station TS1 includes an optical transmission device 100 and optical transceivers TPD1 and TPD2, and the optical transmission device 100 and the optical transceivers TPD1 and TPD2 constitute a terminal device in the terminal station TS1.

[0053] The optical transceivers TPD1 and TPD2 are connected to the optical transmission device 100, for example, via an optical fiber, and communicate optical signals with another terminal station or the like via the optical transmission device 100. The plurality of optical transceivers included in the terminal station do not have to be optical transceivers of the same type, and optical transceivers having different functions or optical transceivers from different suppliers can be appropriately used.

[0054] In this example, an optical signal L1 is input from the optical transceiver TPD1, ​​and an optical signal L2 is input from the optical transceiver TPD2 to the optical transmission device 100. Each of the optical signals L1 and L2 includes an optical signal having one or more wavelengths.

[0055] The optical transmission device 100 combines the optical signal L1 with the optical signal L2, and generates a wavelength-multiplexed optical signal L including the combined optical signal and dummy light. In addition, in order to compensate for the wavelength dependence of the light intensity caused by the nonlinear effect and loss generated by transmission through the transmission line TL1, the optical transmission device 100 applies an intensity difference (pre-emphasis) to each wavelength based on the inverse wavelength dependence that cancels out such wavelength dependence of the optical signal and the dummy light included in the wavelength-multiplexed optical signal L. After applying the pre-emphasis to the transmission line TL1, the optical transmission device 100 outputs the wavelength-multiplexed optical signal L.

[0056] The following describes pre-emphasis applied to a wavelength multiplexed optical signal. When the wavelength multiplexed optical signal is transmitted through a transmission line, the intensity of the light (optical signal and dummy light) included in the wavelength multiplexed optical signal varies due to nonlinear effects occurring during amplification in an optical amplifier inserted into the transmission line and transmission loss in the transmission line. It is known that the intensity variation of light depends on the wavelength.

[0057] Figure 3 is a diagram showing changes in the intensity of a wavelength-multiplexed optical signal before and after transmission without applying pre-emphasis. Figure 3 The wavelength multiplexed optical signal L shown includes a plurality of dummy lights D having different central wavelengths. In this example, the dummy lights D have the same intensity before being input to the transmission line.

[0058] When a wavelength multiplexed optical signal L is transmitted through a transmission line, as Figure 3As shown, the intensity of the dummy light D varies differently depending on its wavelength. As a result, the intensity of the dummy light D becomes non-uniform. Thus, when the wavelength-multiplexed optical signal L is transmitted as the optical signal L is multiplexed, the intensity of the optical signal also becomes non-uniform. Preferably, since the intensity of the optical signal included in the wavelength-multiplexed optical signal is uniform after transmission, pre-emphasis is applied to the wavelength-multiplexed optical signal before transmission in order to offset the wavelength dependence of the intensity variation occurring after transmission.

[0059] Figure 4 FIG. 1 is a diagram showing intensity changes of a wavelength multiplexed optical signal before and after transmission with pre-emphasis applied. Figure 4 In the embodiment, a wavelength multiplexed optical signal L to which pre-emphasis is applied is used. The pre-emphasis is applied to the wavelength multiplexed optical signal before transmission including a plurality of dummy lights having uniform intensity. Figure 3 The inverse wavelength dependence of the wavelength dependence after transmission is shown. Figure 4 , as indicated by hatching, the intensity of the dummy light D included in the wavelength multiplexed optical signal L before transmission is adjusted by pre-emphasis.

[0060] When the wavelength multiplexed optical signal L after applying pre-emphasis is transmitted through the transmission line, Figure 3 However, in this example, because the intensity difference (pre-emphasis) of each wavelength is applied to the wavelength multiplexed optical signal L before transmission based on the inverse wavelength dependency, the wavelength dependency caused by transmission is offset by the inverse wavelength dependency. Figure 4 , as indicated by hatching, the intensity of the dummy light D included in the wavelength-multiplexed optical signal L after transmission is compensated by pre-emphasis.

[0061] As a result, the intensities of dummy lights having a plurality of wavelengths included in the wavelength-multiplexed optical signal L after transmission are made equal.

[0062] In addition, just like the dummy light, the intensity of the optical signal after transmission also varies depending on the wavelength. Therefore, by inserting the optical signal into the wavelength multiplexed optical signal and applying pre-emphasis, the intensity of the light after transmission is equalized.

[0063] The following describes the relationship between the intensity of the dummy light and the intensity of the optical signal. Multiple dummy lights with different central wavelengths are inserted into the wavelength multiplexed optical signal, and each dummy light is controlled so that the total intensity of the light included in a specific band remains constant. In this example, the band whose total intensity of light is kept constant by one dummy light is called the coverage band of the dummy light.

[0064] For clarity of explanation, hereinafter, "bandwidth" means a width defined by a lower limit and an upper limit in a frequency band or a wavelength band, and "band" means a range having a predetermined "bandwidth" centered on a predetermined center wavelength. In other words, the "bandwidth" can be quantitatively defined using a numerical value, and the "band" is used to confirm a range having a predetermined "bandwidth" set at different positions of a frequency band or a wavelength band (such as a first band or a second band).

[0065] Figure 5 A plurality of dummy lights and corresponding cover bands are schematically shown. As an example, Figure 5 Dummy lights DA to DC with different central wavelengths are shown. Figure 5 In the figure, the bandwidth occupied by the virtual light DA to DC is shown as W DA To W DC For the dummy optical DA to DC, the settings include bandwidth W DA To W DC Note that the bandwidth W excluding the dummy light DA to DC can be DA To W DC The ranges are set to cover bands BA to BC. In addition, the bandwidths of the covering bands BA to BC are bandwidths W BA To W BC .

[0066] exist Figure 5 In the band shown, when an optical signal is inserted into the wavelength multiplexed optical signal, it is determined to which of the cover bands BA to BC the inserted optical signal belongs, thereby determining the dummy light whose intensity is to be controlled.

[0067] When inserting an optical signal into a certain cover band, the intensity of the optical signal to be inserted (hereinafter referred to as a target value) can be determined based on the bandwidth of the cover band when the optical signal is not inserted into the cover band and the intensity of the dummy light.

[0068] Figure 6 The relationship between the intensity of the dummy light and the target value of the optical signal is shown. The following description focuses on the cover band BB. In the case where the optical signal is not inserted into the cover band BB, the intensity of the dummy light DB set in consideration of pre-emphasis is P DB0 (hereinafter referred to as the virtual light intensity initial value). LB In the case where the optical signal LB is inserted into the cover tape BB, the intensity of the dummy light DB is controlled so that the total intensity of the light included in the cover tape BB remains constant before and after the insertion.

[0069] Specifically, when the optical signal LB is inserted, the total intensity of the light included in the cover band BB increases by the target value P of the optical signal LB. LB The bandwidth W of the optical signalLB To offset this increase, it is necessary to reduce the intensity of the dummy light DB. Determine the intensity P of the dummy light DB after inserting the optical signal DB1 Satisfies the following formula [1].

[0070] [Formula 1]

[0071] P LB W LB +P DB1 W DB =P DB0 W DB [1]

[0072] Therefore, the intensity P of the virtual light DB after the optical signal is inserted DB1 It is expressed by the following formula [2].

[0073] [Formula 2]

[0074]

[0075] On the other hand, even when the inserted optical signal LB is eliminated from the cover tape BB, by changing the intensity of the dummy light from P DB1 Increase to P D0 , the total intensity of the light included in the cover band BB also remains constant.

[0076] The following describes the determination of the target value P of the optical signal LB. LB Example. Target value P of the optical signal LB LB The initial light intensity value P can be set in the cover band BB. DB0 The bandwidth W of the virtual light DB DB Specifically, the target value P of the intensity of the optical signal is LB The initial light intensity value P can be set DB0 The bandwidth W of the virtual light DB DB The product of divided by the bandwidth W of the covering band BB BB to calculate.

[0077] [Formula 3]

[0078]

[0079] An example of inserting or removing one optical signal into or from one coverage band has been described above. However, note that even when multiple optical signals are inserted or removed, the intensity of dummy light may increase or decrease for each optical signal to be inserted or removed.

[0080] As described above, by controlling the intensity of the corresponding dummy light according to the insertion or elimination of the optical signal, the total intensity of the light included in each coverage band of the dummy light is kept constant. In addition, the center wavelength of the dummy light corresponding to a specific coverage band and the optical signal inserted into the coverage band are relatively closer to each other, so it is considered that similar intensity changes occur after transmission. Therefore, even when the optical signal is inserted into a specific coverage band, the inverse wavelength dependence relative to the wavelength dependence caused by the transmission of the wavelength multiplexed optical signal with pre-emphasis applied is maintained. Accordingly, the intensity of the optical signal after transmission is equalized.

[0081] The following describes an optical transmission device 100 according to a first exemplary embodiment. Figure 7 The configuration of an optical transmission device 100 according to the first exemplary embodiment is schematically shown. The optical transmission device 100 includes an optical signal adjustment unit 1 , a dummy light output unit 2 , a multiplexing unit 3 , and a control unit 4 .

[0082] For example, the optical signal adjustment unit 1 is configured to be able to adjust the intensity of each wavelength component included in the input optical signal, and is configured as a wavelength selective switch (WSS). The optical signal L1 and the optical signal L2 are input to the optical signal adjustment unit 1. The optical signal adjustment unit 1 combines the optical signal L1 with the optical signal L2, adjusts the intensity of each wavelength component included in the combined signal, thereby applying pre-emphasis, and then outputs the adjusted optical signal L10 to the multiplexing unit 3.

[0083] The optical signal adjustment unit 1 is capable of separating the wavelength components included in the optical signal L1 and the optical signal L2, assigning them to different ports, and independently adjusting the intensity of the optical signal in each port. An optical attenuator is arranged in each port of the optical signal adjustment unit 1, and the intensity of the optical signal corresponding to each port can be adjusted by controlling the attenuation rate of the optical attenuator.

[0084] The dummy light output unit 2 outputs a plurality of dummy lights having different central wavelengths to the multiplexing unit 3. Figure 7 In FIG. 1 , the dummy light output from the dummy light output unit 2 is collectively represented by symbol D.

[0085] The multiplexing unit 3 combines the optical signal L10 with the dummy light D, and outputs the wavelength-multiplexed optical signal L to the transmission line TL1 .

[0086] The control unit 4 is configured to control the intensity adjustment operation of the optical signal adjustment unit 1 by providing a control signal C1, and also to control the intensity of each wavelength component of the dummy light D output from the dummy light output unit 2 by providing a control signal C2. An instruction signal INS indicating pre-emphasis to be applied to the wavelength multiplexed optical signal L is input from the management server 1001 or the like to the control unit 4. The control unit 4 outputs control signals C1 and C2 in response to the instruction signal INS.

[0087] Next, the operation of the optical transmission device 100 in the case where a new optical signal LB is added to the wavelength-multiplexed optical signal L is described. Figure 8 is a flowchart showing the operation of the optical transmission device 100 in the case where the optical signal LB is added. Fig. 9 An example of connecting a new optical transceiver TPD to the terminal station TS1 according to the first exemplary embodiment is schematically shown. Fig.10 An example of inputting a new optical signal LB to the optical transmission device 100 of the terminal station TS1 according to the first exemplary embodiment is schematically shown.

[0088] In this example, if Fig. 9 As shown, the new optical transceiver TPD is connected to the optical transmission device 100 in the terminal station TS1. The optical transceiver TPD outputs a new optical signal LB to the optical transmission device 100.

[0089] The management server 1001 outputs an instruction signal INS including information notifying the addition of a new optical transceiver TPD to the optical transmission device 100. The instruction signal INS includes at least information indicating a center wavelength of an optical signal LB output from the added optical transceiver TPD.

[0090] Step SA11

[0091] The control unit 4 receives the instruction signal INS.

[0092] Step SA12

[0093] The control unit 4 confirms the port in the optical signal adjustment unit 1 corresponding to the center wavelength of the optical signal LB to be inserted by referring to the table TAB stored therein.

[0094] Step SA13

[0095] The control unit 4 reads the target value P of the optical signal LB by referring to the table TAB. LB In addition, the control unit 4 confirms the dummy light DB corresponding to the optical signal LB by referring to the table TAB. The control unit 4 reads the setting value P of the intensity of the dummy light DB after the optical signal is inserted. DB1 .

[0096] Step SA14

[0097] The control unit 4 outputs the control signal C1 to the optical signal adjustment unit 1 so as to adjust the intensity of the added optical signal LB to the target value P LB In response to the control signal C1, the optical signal adjustment unit 1 first maximizes the attenuation rate of the optical signal LB at the confirmed port. This prevents the optical signal LB from being erroneously output with an unexpected intensity when the optical signal LB is inserted. Thereafter, the optical signal adjustment unit 1 adjusts the attenuation rate at the confirmed port, thereby adjusting the intensity of the optical signal LB to the target value P LB .

[0098] Step SA15

[0099] The control unit 4 outputs a control signal C2 to the dummy light output unit 2 so as to adjust the intensity of the dummy light DB corresponding to the optical signal LB to P. DB1 In response to the control signal C2, as Figure 6 As shown, the dummy light output unit 2 changes the intensity of the dummy light DB from P DB0 Adjust to P DB1 .

[0100] As mentioned above, according to Figure 8 The operation shown can adjust the intensity of the inserted optical signal to an appropriate value, and can also adjust the intensity of the corresponding dummy light to an appropriate value. Therefore, the total intensity of the light in the coverage band of the inserted optical signal can be maintained, and the inverse wavelength dependence that offsets the wavelength dependence caused by transmission can be applied to the wavelength multiplexed optical signal.

[0101] The following describes the case where the optical signal LB is eliminated from the cover band BB. Fig.11 is a flowchart showing the operation of the optical transmission device 100 in the case where the optical signal LB is eliminated from the cover tape BB.

[0102] In this example, the optical transmission device 100 is removed. Fig. 9 The optical transceiver TPD shown. Therefore, the input of the optical signal LB to the optical transmission device 100 is interrupted.

[0103] The management server 1001 outputs an instruction signal INS including information notifying the optical transmission device 100 of removing the optical transceiver TPD from the optical transmission device 100. The instruction signal INS includes at least information indicating the center wavelength of the optical signal LB to be interrupted.

[0104] Step SB11

[0105] The control unit 4 receives the instruction signal INS.

[0106] Step SB12

[0107] The control unit 4 confirms the port of the optical signal adjustment unit 1 corresponding to the wavelength of the optical signal LB to be interrupted by referring to the table TAB.

[0108] Step SB13

[0109] The control unit 4 reads the intensity initial value P of the dummy light DB to be used after the optical signal LB is interrupted by referring to the table TAB. DB0 .

[0110] Step SB14

[0111] The control unit 4 outputs a control signal C1 to the optical signal adjustment unit 1 to interrupt the optical signal LB. In response to the control signal C1, the optical signal adjustment unit 1 maximizes the attenuation rate of the optical signal LB at the confirmed port. Thus, the optical signal LB is interrupted.

[0112] Step SB15

[0113] The control unit 4 outputs a control signal C2 to the dummy light output unit 2 so as to adjust the intensity of the dummy light DB. Fig.12 FIG. 4 shows the intensity of the dummy light DB when the optical signal LB is eliminated. Fig.12 As shown, the dummy light output unit 2 changes the intensity of the dummy light DB from P DB1 Increase to P DB0 .

[0114] As mentioned above, according to Fig.11 The operation shown in the figure, when an optical signal with a certain wavelength is interrupted, the intensity of the corresponding dummy light can be increased by an appropriate value. Therefore, the decrease in the intensity of the optical signal when the optical signal is interrupted can be compensated by increasing the intensity of the dummy light, and the wavelength dependency that offsets the wavelength dependency caused by transmission can be applied to the wavelength multiplexed optical signal.

[0115] Second exemplary embodiment

[0116] The following describes an optical transmission device 200 according to a second exemplary embodiment. Fig.13 The configuration of an optical transmission device 200 according to the second exemplary embodiment is schematically shown. The optical transmission device 200 has a configuration in which a demultiplexer 5 and a photodetector 6 are added to the optical transmission device 100 according to the first exemplary embodiment.

[0117] The demultiplexer 5 branches off a part of the optical signal L10 output from the optical signal adjustment unit 1 , and outputs the branched part of the optical signal L10 to the photodetector 6 .

[0118] The photodetector 6 is configured to be capable of detecting the intensity of each of the optical signals having a plurality of wavelengths included in the optical signal L10 output from the optical signal adjustment unit 1 .

[0119] The other configurations of the optical transmission device 200 are the same as those of the optical transmission device 100 , and thus will not be described in detail.

[0120] Next, the operation of the optical transmission device 200 in the case of inserting the new optical signal LB into the wavelength-multiplexed optical signal L is described. Fig.14 : is a flowchart showing the operation of the optical transmission device 200 in the case where a new optical signal LB is inserted.

[0121] In this example, as described in the first exemplary embodiment, the new optical transceiver TPD is connected to the optical transmission device 200 in the terminal station TS1. The new optical transceiver TPD outputs a new optical signal LB to the optical transmission device 100.

[0122] The management server 1001 outputs an instruction signal INS including information notifying the addition of the optical transceiver TPD to the optical transmission device 200. The instruction signal INS includes at least information indicating the port information of the optical signal adjustment unit 1 corresponding to the optical signal LB.

[0123] Step SA21

[0124] The control unit 4 receives the instruction signal INS and thereby recognizes that the new optical signal LB is inserted into the confirmed port.

[0125] Step SA22

[0126] Although the port of the optical signal adjustment unit 1 to which the inserted optical signal LB is input has the maximum attenuation rate at this time, the optical signal LB will not be completely interrupted even if the attenuation rate is the maximum. Therefore, although the intensity of the optical signal is very low, a part of the optical signal still leaks. Therefore, when the optical signal LB is input to the optical signal adjustment unit 1, the photodetector 6 can detect the optical signal LB leaked from the optical signal adjustment unit 1. In this case, the photodetector 6 detects the wavelength of the optical signal LB and outputs a detection signal DET indicating the detection result to the control unit 4.

[0127] Step SA23

[0128] The control unit 4 confirms the wavelength of the optical signal LB based on the detection signal DET, thereby confirming the corresponding dummy light DB and cover tape BB by referring to the table TAB.

[0129] Steps SA24 to SA26

[0130] Steps SA24 to SA26 are respectively Figure 8 Steps SA13 to SA15 are the same as those in the above, so they will not be repeated here.

[0131] As mentioned above, according to Fig.14 The operation shown, as described in the first exemplary embodiment, can adjust the intensity of the inserted optical signal to an appropriate value, and can also adjust the intensity of the corresponding dummy light to an appropriate value. Therefore, the total intensity of the light included in the coverage band of the inserted optical signal can be maintained, and the wavelength dependence that cancels the wavelength dependence occurring due to transmission can be applied to the wavelength multiplexed optical signal.

[0132] Next, the operation of the optical transmission device 200 in the case where the optical signal LB is eliminated from the wavelength-multiplexed optical signal L is described. Fig.15 2 is a flowchart showing the operation of the optical transmission device 200 in the case where the optical signal LB is eliminated from the wavelength-multiplexed optical signal L.

[0133] In this example, as described in the first exemplary embodiment, the optical transceiver TPD is removed from the optical transmission device 200, so that the input of the optical signal LB to the optical transmission device 200 is interrupted.

[0134] The management server 1001 outputs an instruction signal INS including information notifying the optical transmission device 200 of removing the optical transceiver TPD from the optical transmission device 200 .

[0135] Step SB21

[0136] The control unit 4 receives the instruction signal INS, and thereby recognizes that the optical signal LB is removed from the confirmed port.

[0137] Step SB22

[0138] The control unit 4 outputs a control signal C1 to the optical signal adjustment unit 1 to cause the optical signal adjustment unit 1 to interrupt the optical signal LB. In response to the control signal C1, the optical signal adjustment unit 1 maximizes the attenuation rate of the optical signal LB at the confirmed port.

[0139] Step SB23

[0140] The photodetector 6 detects the wavelength of the optical signal whose intensity has changed by more than a predetermined threshold value, thereby detecting the wavelength of the optical signal LB. The photodetector 6 outputs a detection signal DET indicating the wavelength of the optical signal LB to the control unit 4.

[0141] Step SB24

[0142] The control unit 4 confirms the wavelength of the optical signal LB based on the detection signal DET. Then, the control unit 4 confirms the dummy light DB corresponding to the wavelength of the optical signal LB by referring to the table TAB.

[0143] Steps SB25 and SB26

[0144] Steps SB25 and SB26 are respectively Fig.12 Steps SB13 and SB15 are the same, so they are not repeated here.

[0145] As mentioned above, according to Fig.15 According to the operation shown, when an optical signal having a certain wavelength is interrupted as described in the first exemplary embodiment, the intensity of the corresponding dummy light can be adjusted to an appropriate value. Therefore, the decrease in the intensity of the optical signal when the optical signal is interrupted can be compensated by increasing the intensity of the dummy light, and the wavelength dependency that cancels the wavelength dependency occurring due to transmission can be applied to the wavelength multiplexed optical signal.

[0146] Third exemplary embodiment

[0147] The following describes an optical transmission device according to a third exemplary embodiment. In the third exemplary embodiment, the operation of the optical transmission device in a case where the optical signal LB to be inserted overlaps with the corresponding dummy light DB is described. Note that the configuration of the optical transmission device according to the third exemplary embodiment is the same as the configuration of the optical transmission device 100 according to the first exemplary embodiment, so it will not be described in detail.

[0148] The following describes the operation of the optical transmission device according to the third exemplary embodiment. Fig.16 : is a flowchart showing an operation in the case where an optical signal LB is added to the optical transmission device according to the third exemplary embodiment.

[0149] As described in the first exemplary embodiment, the management server 1001 outputs the instruction signal INS including information notifying the addition of the new optical transceiver TPD to the optical transmission device 300. The instruction signal INS includes at least information indicating the center wavelength of the optical signal LB.

[0150] Fig.16 Steps SA11 to SA15 in Fig.12 The following describes Fig.16 Steps SA31 to SA34 added in .

[0151] Step SA31

[0152] The control unit 4 determines whether the bands occupied by the optical signal LB and the dummy light DB overlap. Fig.17The case where the bands occupied by the optical signal LB and the dummy light DB overlap is shown.

[0153] Step SA32

[0154] When the bands occupied by the optical signal LB and the dummy light DB overlap, it is necessary to prevent the optical signal LB from being hidden in the dummy light DB. Therefore, the control unit 4 outputs the control signal C2 to the dummy light output unit 2 to interrupt the output of the dummy light DB. In response to the control signal C2, the dummy light output unit 2 stops outputting the dummy light DB.

[0155] Step SA33

[0156] As a result, the dummy light DB does not exist in the cover band BB of the dummy light DB. Thus, in this exemplary embodiment, an alternative process of compensating for the dummy light DB in the cover band BB by another cover band is performed.

[0157] First, a case is described in which the compensation function of the dummy light DB in the cover strip BB is replaced by an adjacent cover strip BA. Fig.18 The optical signal and the dummy light are shown in the case where the compensation function of the dummy light DB in the cover tape BB is performed by the cover tape BA instead. In this example, the initial value of the dummy light intensity of the cover tape BA before the replacement process is P DA0 In this case, it is necessary to increase the initial value of the virtual light intensity of the cover band BA after the replacement process to a value greater than P DA0 .

[0158] In this case, the total intensity of the light in the cover bands BA and BB needs to be kept constant before and after the replacement process. Therefore, the initial value P of the intensity of the dummy light in the cover band BA after the replacement process is DA1 It is expressed by the following formula.

[0159] [Formula 4]

[0160] P DB0 W DB +P DA0 W DA =P DA1 W DA [4]

[0161] [Formula 5]

[0162]

[0163] Then, the control unit 4 reads the target value P of the optical signal LB by referring to the table TAB. LB At this time, as shown in formula [1], the control unit 4 can set the target value P of the optical signal LB to be inserted LB Update to the value obtained by the following formula [6].

[0164] [Formula 6]

[0165]

[0166] As shown in formula [3], the control unit 4 can calculate the target value P of the optical signal LB. LB To determine the intensity P of the virtual light DA after the optical signal is inserted DA2 .

[0167] [Formula 7]

[0168]

[0169] Next, the following describes a case where the compensation function of the dummy light DB in the cover band BB is performed alternatively by two adjacent cover bands BA and BC. Fig.19 The optical signal and dummy light are shown in the case where the compensation function of the dummy light DB in the cover tape BB is performed by the cover tapes BA and BC instead. In this example, the initial value of the dummy light intensity of the dummy light DC before the replacement process is P DC0 In this case, the initial values ​​of the virtual light intensity of the cover bands BA and BC after the replacement process need to be increased to be greater than P DA0 and P DC0 .

[0170] In this case, the total intensity of the light included in the cover bands BA and BC needs to be kept constant before and after the replacement process. Therefore, the initial value P of the intensity of the dummy light in the cover bands BA and BC after the replacement process is determined. DA1 and P DC1 Satisfy the following formula.

[0171] [Formula 8]

[0172] P DB0 W DB +P DA0 W DA +P DC0 W DC =P DA1 W DA +PD DC1 W DC [8]

[0173] Note that considering the initial value of the intensity before the substitution process, the initial value P of the intensity of the dummy light in the cover bands BA and BC after the substitution process can be determined. DA1 and P DC1 The following relationship is satisfied.

[0174] [Formula 9]

[0175] P DA1 :P DC1 =PDA0 :P DC0 [9]

[0176] [Formula 10]

[0177]

[0178] Then, the control unit 4 reads the target value P of the optical signal LB by referring to the table TAB. LB At this time, as shown in formula [1], the control unit 4 can set the target value P of the optical signal LB LB Update to the value obtained by the following formula

[11] .

[0179] [Formula 11]

[0180]

[0181] In addition, the control unit 4 can set the target value P of the optical signal LB LB Update to the value obtained by the following formula

[12] .

[0182] [Formula 12]

[0183]

[0184] The control unit 4 can be configured to generate a target value P of the optical signal LB according to the target value P of the optical signal LB. LB To determine the intensity P of the virtual light DA and DC after the optical signal is inserted DA2 and P DC2 At this time, considering the initial value of the intensity before the replacement process, the intensity P of the dummy light DA and DC after the optical signal is inserted can be determined based on the following formula: DA2 and P DC2 .

[0185] [Formula 13]

[0186]

[0187] [Formula 14]

[0188]

[0189] Note that after the output of the dummy light DB is stopped, the cover band BB may be deleted, and a portion of the cover band BB may be assigned to the cover bands BA and BC. In other words, the cover bands BA and BC may be expanded. When the entire band of the dummy light DB whose output is stopped is included in the expanded cover band BA, the initial value of the intensity of the dummy light DA may be increased.

[0190] In addition, there may be a case where the band of the dummy light DB that stops output is included in the expanded cover bands BA and BC. In this case, the increase amount of the initial value of the dummy light intensity of the cover bands BA and BC after the replacement process can be set according to the band amount of the dummy light DB included in each of the cover bands BA and BC. For example, when the bandwidth of the dummy light DB included in the cover band BC is wider than the bandwidth of the dummy light DB included in the cover band BA, the increase amount of the initial value of the dummy light intensity of the dummy light DC can be set to be greater than the increase amount of the initial value of the dummy light intensity of the dummy light DA.

[0191] Step SA34

[0192] The control unit 4 outputs a control signal C2 to the dummy light output unit 2 to control the intensity of the substitute dummy light. In response to the control signal C2, the dummy light output unit 2 adjusts the intensity of the substitute dummy light to the calculated value.

[0193] As described above, according to the optical transmission device according to this exemplary embodiment, even when the wavelength of the inserted optical signal overlaps the band of the corresponding dummy light, the overlapping dummy light can be interrupted and replaced with dummy light in another covering band. Therefore, the total intensity of the light in the band covered by the replacement dummy light can be maintained when the optical signal is inserted, and the wavelength dependence that cancels the wavelength dependence occurring due to transmission is applied to the wavelength multiplexed optical signal.

[0194] Fourth exemplary embodiment

[0195] The following describes an optical transmission device according to a fourth exemplary embodiment. In the fourth exemplary embodiment, the operation of the optical transmission device in a case where the optical signal LB to be inserted overlaps two cover bands is described. Note that the configuration of the optical transmission device according to the fourth exemplary embodiment is the same as the configuration of the optical transmission device 100 according to the first exemplary embodiment, so it will not be described in detail.

[0196] The following describes the operation of the optical transmission device according to the fourth exemplary embodiment. Fig. 20 : is a flowchart showing an operation in a case where an optical signal LB is added to the optical transmission device according to the fourth exemplary embodiment.

[0197] As described in the first exemplary embodiment, the management server 1001 outputs the instruction signal INS including information notifying the addition of the new optical transceiver TPD to the optical transmission device 400. The instruction signal INS includes information indicating the center wavelength of the optical signal LB.

[0198] Fig. 20 Steps SA11 to SA15 in Figure 8 The following describes Fig. 20Steps SA41 to SA43 added in .

[0199] Step SA41

[0200] The control unit 4 determines whether the optical signal LB overlaps with two cover bands. For simplicity of description, in this example, the control unit 4 determines whether the optical signal LB overlaps with the corresponding cover band BB and the adjacent cover band BA. Fig.21 The situation where the optical signal LB overlaps with two cover bands BB and BA is shown.

[0201] Step SA42

[0202] In the present exemplary embodiment, when the optical signal LB overlaps the two cover bands BB and BA, the compensation function of the dummy light DB in the cover band BB is distributed between the dummy light DB and the dummy light DA. Fig. 22 The optical signal and the dummy light are shown in the case where the compensation function of the dummy light DB in the cover light band BB is distributed between the dummy light DB and the dummy light DA.

[0203] The control unit 4 reads the target value P of the optical signal LB by referring to the table TAB. LB At this time, the control unit 4 can update the target value P of the optical signal LB to be inserted based on formula

[15] LB .

[0204] [Formula 15]

[0205]

[0206] As shown in equation [1], the control unit 4 can update the target value P of the optical signal LB to be inserted based on equation

[16] LB .

[0207] [Formula 16]

[0208]

[0209] In this case, the total intensity of light included in the cover bands BA and BB needs to be constant before and after the insertion of the optical signal LB. Therefore, the virtual light intensity P in the cover bands BA and BB before and after the insertion of the optical signal LB is determined. DA1 and P DB1 Satisfy the following formula.

[0210] [Formula 17]

[0211] P DB0 W DB +P DA0 W DA =P DA1 W DA +P DB1 WDB +P LB W LB

[17]

[0212] Note that considering the initial value of the intensity before insertion, the virtual light intensity P in the cover bands BA and BB after the insertion of the optical signal can be determined as DA1 and P DB1 The following relationship is satisfied.

[0213] [Formula 18]

[0214] P DA1 :P DB1 =P DA0 :P DB0

[18]

[0215] [Formula 19]

[0216]

[0217] In addition, the dummy light intensity P in the cover bands BA and BB after the optical signal is inserted may be set according to the bandwidth of the optical signal LB included in each of the cover bands BA and BC. DA1 and P DB1 For example, there may be a case where the band of the optical signal LB included in the cover band BB is wider than the band of the optical signal LB included in the cover band BA. In this case, the initial value P of the virtual light intensity may be DA0 To the virtual light intensity P DA1 The reduction amount is set to be greater than the initial value P of the virtual light intensity DB0 To the virtual light intensity P DB1 of reduction.

[0218] Step SA43

[0219] The control unit 4 outputs a control signal C2 to the dummy light output unit 2 to control the intensity of the dummy lights DA and DB. In response to the control signal C2, the dummy light output unit 2 adjusts the intensity of the substitute dummy light to the calculated value.

[0220] As described above, according to the optical transmission device according to this exemplary embodiment, even when the inserted optical signal overlaps the two cover bands, the intensity of the dummy light in the two cover bands can be adjusted according to the target value of the inserted optical signal. Therefore, the total light intensity in the two cover bands can be maintained, and the wavelength dependence that cancels the wavelength dependence occurring due to transmission can be applied to the wavelength multiplexed optical signal.

[0221] Fifth exemplary embodiment

[0222] The following describes an optical transmission device according to a fifth exemplary embodiment. Figure 5 Examples of dummy lights and corresponding cover bands are described. Figure 5 In the illustrated example (first example), although the dummy light is inserted substantially at the center of the cover tape, this is only an example.

[0223] Fig.23 A second example of a dummy light and a cover band corresponding thereto is shown. In this example, the boundary of the cover band is arranged at the midpoint between the opposite edges of two adjacent dummy lights. Specifically, the boundary between the cover band BA and the cover band BB is arranged at the midpoint between the edge of the dummy light DA on the long wavelength side and the edge of the dummy light DB on the short wavelength side. The boundary between the cover band BB and the cover band BC is arranged at the midpoint between the edge of the dummy light DB on the long wavelength side and the edge of the dummy light DC on the short wavelength side.

[0224] Fig.24 A third example of dummy light and a cover band corresponding thereto is shown. The third example is a modified example of the second example, and the guard band GBC is arranged on the short wavelength side of the dummy light DC. The guard band GBC is set as a band that does not include the dummy light and the signal light. As described in the second example, the boundary between the cover band BA and the cover band BB is arranged at the midpoint between the edge of the dummy light DA on the long wavelength side and the edge of the dummy light DB on the short wavelength side.

[0225] The boundary of the cover band BB on the long wavelength side is arranged at the edge of the guard band GBC on the short wavelength side. In addition, the boundary of the cover band BC on the short wavelength side is arranged at the edge of the guard band GBC on the long wavelength side. That is, the cover band BB and the cover band BC are set to not include the guard band GBC. Therefore, since the band into which the signal light can be inserted matches the cover band, the target value can be calculated by averaging the product of the initial value of the intensity of the dummy light and the bandwidth of the dummy light according to the band into which the signal light can be inserted. As a result, the output wavelength multiplexed optical signal can accurately approximate the intensity distribution in consideration of the wavelength dependence in the transmission line. Note that the cover band can be set to include the guard band.

[0226] Fig.25 A fourth example of dummy light and the corresponding cover band is shown. In this example, dummy light DA on the short wavelength side is placed at the short wavelength side end of the band monitored in the system using the optical transmission device. In this case, the boundary of the cover band BA on the short wavelength side is set to the lower limit value λL of the monitoring band on the short wavelength side. Note that the boundary between the cover band BB and the cover band BC can be placed at the midpoint between the edge of the dummy light DB on the long wavelength side and the edge of the dummy light DC on the short wavelength side.

[0227] Fig.26A fifth example of dummy light and the corresponding cover band is shown. In this example, the guard band GBA is arranged on the long wavelength side of the dummy light DA, and the guard band GBB is arranged on the short wavelength side of the dummy light DB. The guard band GBA is set as a band that does not include the dummy light and the signal light.

[0228] The boundary of the cover band BA on the long wavelength side is arranged at the edge of the guard band GBA on the short wavelength side. The boundary of the cover band BB on the short wavelength side is arranged at the edge of the guard band GBB on the long wavelength side. There is no cover band between the edge of the guard band GBA on the long wavelength side and the edge of the guard band GBB on the short wavelength side. Therefore, since the band of the insertable signal light matches the cover band, the target value can be calculated by averaging the product of the initial value of the virtual light intensity and the bandwidth of the virtual light according to the band of the insertable signal light. As a result, the output wavelength multiplexed optical signal can accurately approximate the intensity distribution in consideration of the wavelength dependence in the transmission line. Note that the cover band can be set to include the guard band.

[0229] Note, however, that the band between the edge of the guard band GBA on the long wavelength side and the edge of the guard band GBB on the short wavelength side may be included in the cover band BA, or may be included in the cover band BB, as necessary.

[0230] The above-described second to fifth examples may be applied to the optical transmission devices according to the first to fourth exemplary embodiments, as necessary.

[0231] Other Example Embodiments

[0232] Note that the present invention is not limited to the above-described exemplary embodiments, and various changes may be made without departing from the spirit and scope of the present invention. For example, in the third exemplary embodiment and the fourth exemplary embodiment, an example of realizing the compensation function of one dummy light by two dummy lights is described. However, the compensation function of one dummy light may be realized by three or more dummy lights.

[0233] For example, all or part of the exemplary embodiments disclosed above may be described as, but not limited to, the following notes.

[0234] (Note 1) An optical transmission device, comprising: an optical signal adjustment unit, the optical signal adjustment unit being configured to be capable of receiving an input of a plurality of optical signals having different wavelengths, adjusting the intensity of each of the plurality of optical signals based on an intensity variation in a transmission line, and outputting an optical signal; a dummy light output unit, the dummy light output unit being configured to output a plurality of dummy lights having different wavelengths, each dummy light having an intensity based on an intensity variation in the transmission line; a control unit, the control unit being configured to confirm a dummy light corresponding to each of the optical signals, and to control the intensity of the confirmed dummy light based on the intensity of the optical signal corresponding to the confirmed dummy light and output from the optical signal adjustment unit; and a multiplexing unit, the multiplexing unit being configured to combine the dummy light with the optical signal output from the optical signal adjustment unit to output a wavelength-multiplexed optical signal.

[0235] (Supplementary Note 2) The optical transmission device according to Supplementary Note 1, wherein the optical signal adjustment unit adjusts the intensities of the plurality of optical signals so that the intensities of the plurality of optical signals after transmission are uniform.

[0236] (Note 3) The optical transmission device according to Note 1 or 2, wherein when receiving information indicating the wavelength of the optical signal to be newly input to the optical signal adjustment unit and inserted into the wavelength multiplexed optical signal, the control unit confirms the dummy light based on the information indicating the wavelength.

[0237] (Note 4) The optical transmission device according to Note 1 or 2 further includes: an optical detection unit, which is configured to be able to detect the wavelengths of the multiple optical signals output from the optical signal adjustment unit, wherein when receiving information notifying that a new optical signal is to be input to the optical signal adjustment unit and inserted into the wavelength multiplexed optical signal, the optical detection unit detects the wavelength of the optical signal whose intensity has changed by more than a predetermined value among the multiple optical signals output from the optical signal adjustment unit, and notifies the control unit of the detected wavelength, and the control unit confirms the dummy light based on the notified wavelength.

[0238] (Note 5) An optical transmission device according to any one of Notes 1 to 4, wherein each of the dummy lights has a cover band having a confirmed bandwidth, and when an optical signal is to be inserted into the cover band, the control unit reduces the intensity of the dummy light corresponding to the cover band according to the intensity of the optical signal to be inserted.

[0239] (Note 6) An optical transmission device according to Note 5, wherein when an optical signal is to be inserted into the cover band, the control unit reduces the intensity of the dummy light in the cover band by a value obtained by dividing the product of the optical signal to be inserted and the bandwidth of the optical signal to be inserted by the bandwidth of the dummy light.

[0240] (Note 7) An optical transmission device according to Note 5 or 6, wherein when the optical signal overlaps with the dummy light, the control unit: interrupts the dummy light overlapping with the optical signal; increases the intensity of the dummy light corresponding to one or more other cover bands according to the intensity of the interrupted dummy light; and reduces the dummy light with the adjusted intensity according to the intensity of the optical signal to be inserted.

[0241] (Supplementary Note 8) The optical transmission device according to any one of Supplementary Notes 5 to 7, wherein when the optical signal overlaps the two cover bands, the control unit reduces the intensity of the dummy light in the two cover bands according to the intensity of the optical signal to be inserted.

[0242] (Note 9) An optical transmission device according to any one of Notes 5 to 8, wherein the target value of the intensity of the optical signal to be inserted is a value obtained by dividing the sum of the products of the pre-adjustment intensity of each of one or more dummy lights whose intensity is adjusted according to the insertion of the optical signal and the bandwidth of each of the one or more dummy lights by the sum of the bandwidths of the cover bands corresponding to the one or more dummy lights.

[0243] (Note 10) An optical transmission device according to any one of Notes 5 to 8, wherein the intensity of the optical signal to be inserted is an average of target values ​​of the intensity when another optical signal is inserted into each cover band of one or more dummy lights whose intensity is to be adjusted according to the insertion of the optical signal.

[0244] (Supplementary Note 11) The optical transmission device according to any one of Supplementary Notes 5 to 10, wherein the dummy light is placed at the center of the corresponding cover band.

[0245] (Supplementary Note 12) The optical transmission device according to any one of Supplementary Notes 5 to 10, wherein a boundary between cover bands corresponding to two adjacent dummy lights is positioned at an intermediate wavelength between the two dummy lights.

[0246] (Note 13) An optical transmission device according to any one of Notes 5 to 10, wherein when a guard band is arranged between two adjacent dummy lights, a boundary between cover bands corresponding to the two dummy lights is arranged at the long wavelength side end or at the long wavelength side end of the guard band.

[0247] (Note 14) An optical transmission device according to any one of Notes 5 to 10, wherein when a predetermined band including a plurality of dummy lights and a plurality of optical signals is arranged, a boundary of a cover band corresponding to the dummy light closest to an end of the predetermined band is arranged at the end of the predetermined band, and the boundary is on one side of the end of the predetermined band.

[0248] (Supplementary Note 15) The optical transmission device according to any one of Supplementary Notes 5 to 10, wherein when two guard tapes are arranged between two adjacent dummy lights, no cover tape is provided between two opposite ends of the two guard tapes.

[0249] (Note 16) A terminal device, comprising: one or more optical transceivers; and an optical transmission device, the optical transmission device being configured to receive input of a plurality of optical signals having different wavelengths from the one or more optical transceivers, wherein the optical transmission device comprises: an optical signal adjustment unit, the optical signal adjustment unit being configured to be able to receive input of the plurality of optical signals, adjust the intensity of each of the plurality of optical signals based on intensity variation in a transmission line, and output the optical signal; a dummy light output unit, the dummy light output unit being configured to output a plurality of dummy lights having different wavelengths, each dummy light having an intensity based on intensity variation in the transmission line; a control unit, the control unit being configured to confirm dummy lights corresponding to each of the optical signals, and to control the intensity of the confirmed dummy lights based on the intensity of the optical signal corresponding to the confirmed dummy lights and output from the optical signal adjustment unit; and a multiplexing unit, the multiplexing unit being configured to combine the dummy lights with the optical signal output from the optical signal adjustment unit to output a wavelength-multiplexed optical signal.

[0250] (Supplementary Note 17) The terminal device according to Supplementary Note 16, wherein the optical signal adjustment unit adjusts the intensities of the plurality of optical signals so that the intensities of the plurality of optical signals after transmission are uniform.

[0251] (Supplementary Note 18) The terminal device according to Supplementary Note 16 or 17, wherein when receiving information indicating a wavelength of an optical signal to be newly input to the optical signal adjustment unit and inserted into the wavelength multiplexed optical signal, the control unit confirms the dummy light based on the information indicating the wavelength.

[0252] (Note 19) The terminal device according to Note 16 or 17 further includes: an optical detection unit, which is configured to be able to detect the wavelengths of the multiple optical signals output from the optical signal adjustment unit, wherein when receiving information notifying that a new optical signal is to be input into the optical signal adjustment unit and inserted into the wavelength multiplexed optical signal, the optical detection unit detects the wavelength of an optical signal whose intensity has changed by more than a predetermined value among the multiple optical signals output from the optical signal adjustment unit, and notifies the control unit of the detected wavelength, and the control unit confirms the dummy light based on the notified wavelength.

[0253] (Note 20) A terminal device according to any one of Notes 16 to 19, wherein each of the dummy lights has a cover band having a confirmed bandwidth, and when an optical signal is to be inserted into the cover band, the control unit reduces the intensity of the dummy light corresponding to the cover band according to the intensity of the optical signal to be inserted.

[0254] (Note 21) A terminal device according to Note 20, wherein when an optical signal is to be inserted into the cover band, the control unit reduces the intensity of the dummy light in the cover band by the value obtained by dividing the product of the optical signal to be inserted and the bandwidth of the optical signal to be inserted by the bandwidth of the dummy light.

[0255] (Note 22) A terminal device according to Note 20 or 21, wherein when the optical signal overlaps with the dummy light, the control unit: interrupts the dummy light overlapping with the optical signal; increases the intensity of the dummy light corresponding to one or more other cover bands according to the intensity of the interrupted dummy light; and reduces the dummy light with the adjusted intensity according to the intensity of the optical signal to be inserted.

[0256] (Supplementary Note 23) The terminal device according to any one of Supplementary Notes 20 to 22, wherein when the optical signal overlaps the two cover bands, the control unit reduces the intensity of the dummy light in the two cover bands according to the intensity of the optical signal to be inserted.

[0257] (Note 24) A terminal device according to any one of Notes 20 to 23, wherein the target value of the intensity of the optical signal to be inserted is a value obtained by dividing the sum of the products of the intensities of each of one or more dummy lights and the bandwidth of each of the one or more dummy lights before adjusting the intensity of the light to be inserted according to the insertion of the optical signal by the sum of the bandwidths of the cover bands corresponding to the one or more dummy lights.

[0258] (Note 25) A terminal device according to any one of Notes 20 to 23, wherein the intensity of the optical signal to be inserted is an average of target values ​​of the intensity when another optical signal is inserted into each coverage band of one or more dummy lights whose intensity is to be adjusted according to the insertion of the optical signal.

[0259] (Supplementary Note 26) The terminal device according to any one of Supplementary Notes 20 to 25, wherein the dummy light is placed at the center of the corresponding coverage band.

[0260] (Supplementary Note 27) The terminal device according to any one of Supplementary Notes 20 to 25, wherein a boundary between cover bands corresponding to two adjacent dummy lights is positioned at an intermediate wavelength between the two dummy lights.

[0261] (Note 28) A terminal device according to any one of Notes 20 to 25, wherein when a guard band is arranged between two adjacent dummy lights, a boundary between cover bands corresponding to the two dummy lights is arranged at the end on the long wavelength side or at the end on the long wavelength side of the guard band.

[0262] (Note 29) A terminal device according to any one of Notes 20 to 25, wherein when a predetermined band including a plurality of dummy lights and a plurality of optical signals is arranged, a boundary of a covering band corresponding to the dummy light closest to the end of the predetermined band is arranged at the end of the predetermined band, and the boundary is on one side of the end of the predetermined band.

[0263] (Supplementary Note 30) The terminal device according to any one of Supplementary Notes 20 to 25, wherein when two guard bands are arranged between two adjacent dummy lights, no cover band is provided between two opposite ends of the two guard bands.

[0264] (Note 31) An optical communication system, comprising: a first terminal station, the first terminal station being configured to output a wavelength multiplexed optical signal; and a second terminal station, the second terminal station being configured to receive the wavelength multiplexed optical signal, wherein the first terminal station comprises: one or more optical transceivers; and an optical transmission device, the optical transmission device being configured to receive input of a plurality of optical signals having different wavelengths from the one or more optical transceivers, and the optical transmission device comprising: an optical signal adjustment unit, the optical signal adjustment unit being configured to receive input of a plurality of optical signals, and to adjust each of the plurality of optical signals based on intensity changes in a transmission line. an intensity of an optical signal and outputs the optical signal; a dummy light output unit, the dummy light output unit being configured to output a plurality of dummy lights having different wavelengths, each dummy light having an intensity based on an intensity variation in the transmission line; a control unit, the control unit being configured to confirm the dummy light corresponding to each of the optical signals and control the intensity of the confirmed dummy light based on the intensity of the optical signal corresponding to the confirmed dummy light and output from the optical signal adjustment unit; and a multiplexing unit, the multiplexing unit being configured to combine the dummy light with the optical signal output from the optical signal adjustment unit to output a wavelength-multiplexed optical signal.

[0265] (Supplementary Note 32) The optical communication system according to Supplementary Note 31, wherein the optical signal adjustment unit adjusts the intensities of the plurality of optical signals so that the intensities of the plurality of optical signals after transmission are uniform.

[0266] (Note 33) The optical communication system according to Note 31 or 32, wherein when receiving information indicating the wavelength of an optical signal to be newly input to the optical signal adjustment unit and inserted into the wavelength multiplexed optical signal, the control unit confirms the dummy light based on the information indicating the wavelength.

[0267] (Note 34) The optical communication system according to Note 31 or 32 further includes: an optical detection unit, which is configured to be able to detect the wavelengths of the multiple optical signals output from the optical signal adjustment unit, wherein when receiving information notifying that a new optical signal is to be input to the optical signal adjustment unit and inserted into the wavelength multiplexed optical signal, the optical detection unit detects the wavelength of an optical signal whose intensity has changed by more than a predetermined value among the multiple optical signals output from the optical signal adjustment unit, and notifies the control unit of the detected wavelength, and the control unit confirms the dummy light based on the notified wavelength.

[0268] (Note 35) An optical communication system according to any one of Notes 31 to 34, wherein each of the dummy lights has a cover band having a confirmed bandwidth, and when an optical signal is to be inserted into the cover band, the control unit reduces the intensity of the dummy light corresponding to the cover band according to the intensity of the optical signal to be inserted.

[0269] (Note 36) An optical communication system according to Note 35, wherein when an optical signal is to be inserted into the cover band, the control unit reduces the intensity of the dummy light in the cover band by a value obtained by dividing the product of the optical signal to be inserted and the bandwidth of the optical signal to be inserted by the bandwidth of the dummy light.

[0270] (Note 37) An optical communication system according to Note 35 or 36, wherein when the optical signal overlaps with the dummy light, the control unit: interrupts the dummy light overlapping with the optical signal; increases the intensity of the dummy light corresponding to one or more other cover bands according to the intensity of the interrupted dummy light; and reduces the dummy light with the adjusted intensity according to the intensity of the optical signal to be inserted.

[0271] (Supplementary Note 38) The optical communication system according to any one of Supplementary Notes 35 to 37, wherein when the optical signal overlaps the two cover bands, the control unit reduces the intensity of the dummy light in the two cover bands according to the intensity of the optical signal to be inserted.

[0272] (Note 39) An optical communication system according to any one of Notes 35 to 38, wherein the target value of the intensity of the optical signal to be inserted is a value obtained by dividing the sum of the products of the intensities of each of the one or more dummy lights and the bandwidth of each of the one or more dummy lights before adjusting the intensity of the one or more dummy lights whose intensities are to be adjusted according to the insertion of the optical signal by the sum of the bandwidths of the cover bands corresponding to the one or more dummy lights.

[0273] (Note 40) An optical communication system according to any one of Notes 35 to 38, wherein the intensity of the optical signal to be inserted is an average of target values ​​of the intensity when another optical signal is inserted into each cover band of one or more dummy lights whose intensity is to be adjusted according to the insertion of the optical signal.

[0274] (Supplementary Note 41) The optical communication system according to any one of Supplementary Notes 35 to 40, wherein the dummy light is placed at the center of the corresponding coverage band.

[0275] (Supplementary Note 42) The optical communication system according to any one of Supplementary Notes 35 to 40, wherein a boundary between the cover bands corresponding to two adjacent dummy lights is positioned at an intermediate wavelength between the two dummy lights.

[0276] (Note 43) An optical communication system according to any one of Notes 35 to 40, wherein when a guard band is arranged between two adjacent dummy lights, a boundary between cover bands corresponding to the two dummy lights is arranged at the long wavelength side end or at the long wavelength side end of the guard band.

[0277] (Note 44) An optical communication system according to any one of Notes 35 to 40, wherein when a predetermined band including a plurality of dummy lights and a plurality of optical signals is arranged, a boundary of a cover band corresponding to the dummy light closest to an end of the predetermined band is arranged at the end of the predetermined band, and the boundary is on one side of the end of the predetermined band.

[0278] (Supplementary Note 45) The optical communication system according to any one of Supplementary Notes 35 to 40, wherein when two guard bands are arranged between two adjacent dummy lights, no cover band is provided between two opposite ends of the two guard bands.

[0279] (Note 46) An optical communication method, comprising: adjusting the intensity of each of a plurality of optical signals having different wavelengths based on intensity variations in a transmission line, and outputting the optical signal; outputting a plurality of dummy lights having different wavelengths, each dummy light having an intensity based on the intensity variations in the transmission line; confirming the dummy light corresponding to each of the optical signals, and controlling the intensity of the confirmed dummy light based on the intensity of the optical signal based on the intensity variations in the transmission line corresponding to the confirmed dummy light; and outputting a wavelength multiplexed optical signal in which the dummy light and the optical signal having the adjusted intensity are combined.

[0280] (Supplementary Note 47) The optical communication method according to Supplementary Note 46, wherein the intensities of the plurality of optical signals are adjusted so that the intensities of the plurality of optical signals after transmission are uniform.

[0281] (Supplementary Note 48) The optical communication method according to Supplementary Note 46 or 47, wherein information indicating a wavelength of the optical signal to be newly inserted into the wavelength multiplexed optical signal is received, and the dummy light is confirmed based on the information indicating the wavelength.

[0282] (Note 49) An optical communication method according to Note 46 or 47, wherein information notifying that a new optical signal is to be inserted into a wavelength multiplexed optical signal is received, a wavelength of an optical signal whose intensity has changed by more than a predetermined value among a plurality of optical signals with adjusted intensities is detected, and dummy light is confirmed based on the detected wavelength.

[0283] (Note 50) An optical communication method according to any one of Notes 46 to 49, wherein each of the dummy lights has a cover band having a confirmed bandwidth, and when an optical signal is to be inserted into the cover band, the intensity of the dummy light corresponding to the cover band is reduced according to the intensity of the optical signal to be inserted.

[0284] (Note 51) An optical communication method according to Note 50, wherein when an optical signal is to be inserted into a cover band, the intensity of the dummy light in the cover band is reduced by a value obtained by dividing the product of the optical signal to be inserted and the bandwidth of the optical signal to be inserted by the bandwidth of the dummy light.

[0285] (Note 52) An optical communication method according to Note 50 or 51, wherein when an optical signal overlaps with dummy light, the dummy light overlapping with the optical signal is interrupted; the intensity of the dummy light corresponding to one or more other cover bands is increased according to the intensity of the interrupted dummy light; and the dummy light with the adjusted intensity is reduced according to the intensity of the optical signal to be inserted.

[0286] (Supplementary Note 53) The optical communication method according to any one of Supplementary Notes 50 to 52, wherein when the optical signal overlaps the two cover bands, the intensity of the dummy light in the two cover bands is reduced according to the intensity of the optical signal to be inserted.

[0287] (Note 54) An optical communication method according to any one of Notes 50 to 53, wherein the target value of the intensity of the optical signal to be inserted is a value obtained by dividing the sum of the products of the intensity before adjustment of each of one or more dummy lights whose intensity is to be adjusted according to the insertion of the optical signal and the bandwidth of each of the one or more dummy lights by the sum of the bandwidths of the cover bands corresponding to the one or more dummy lights.

[0288] (Note 55) An optical communication method according to any one of Notes 50 to 53, wherein the intensity of the optical signal to be inserted is an average of target values ​​of the intensity when another optical signal is inserted into each coverage band of one or more dummy lights whose intensity is to be adjusted according to the insertion of the optical signal.

[0289] (Supplementary Note 56) The optical communication method according to any one of Supplementary Notes 50 to 55, wherein the dummy light is placed at the center of the corresponding cover band.

[0290] (Supplementary Note 57) The optical communication method according to any one of Supplementary Notes 50 to 55, wherein a boundary between cover bands corresponding to two adjacent dummy lights is disposed at an intermediate wavelength between the two dummy lights.

[0291] (Note 58) An optical communication method according to any one of Notes 50 to 55, wherein when a guard band is arranged between two adjacent dummy lights, a boundary between cover bands corresponding to the two dummy lights is arranged at the end on the long wavelength side or at the end on the long wavelength side of the guard band.

[0292] (Note 59) An optical communication method according to any one of Notes 50 to 55, wherein when a predetermined band including a plurality of dummy lights and a plurality of optical signals is arranged, a boundary of a cover band corresponding to the dummy light closest to an end of the predetermined band is arranged at the end of the predetermined band, and the boundary is on one side of the end of the predetermined band.

[0293] (Supplementary Note 60) The optical communication method according to any one of Supplementary Notes 50 to 55, wherein when two guard bands are arranged between two adjacent dummy lights, no cover band is provided between two opposite ends of the two guard bands.

[0294] Although the present invention has been described above with reference to the exemplary embodiments, the present invention is not limited to the exemplary embodiments described above. 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.

[0295] This application is based upon and claims the benefit of priority from Japanese patent application No. 2018-232610, filed on December 12, 2018, the disclosure of which is incorporated herein by reference.

[0296] Reference numerals list

[0297] AMP Optical Amplifier

[0298] BA, BB, BC cover tape

[0299] C1, C2 control signal

[0300] D, DA, DB, DC Dummy light

[0301] DET Detection Signal

[0302] F Fiber Optic

[0303] GBA, GBB, GBC protection belt

[0304] INS command signal

[0305] L wavelength multiplexed optical signal

[0306] L1, L2, L10 optical signals

[0307] LB optical signal

[0308] TAB table

[0309] TL1, TL2 transmission lines

[0310] TPD, TPD1, ​​TPD2 Optical Transceivers

[0311] TS1, TS2 Terminal Station

[0312] 1 Optical signal conditioning unit

[0313] 2 Dummy light output unit

[0314] 3 Multiplexing Unit

[0315] 4 Control unit

[0316] 5 Demultiplexer

[0317] 6 Photodetector

[0318] 100, 200 optical transmission device

[0319] 1000 Optical Communication Systems

[0320] 1001 Management Server

Claims

1. An optical transmission device, comprising: an optical signal adjustment unit configured to be capable of receiving an input of a plurality of optical signals having different wavelengths, adjusting the intensity of each of the plurality of optical signals by applying pre-emphasis, and outputting the optical signal; a dummy light output unit configured to output a plurality of dummy lights having different wavelengths, each dummy light having an intensity to which the pre-emphasis is applied; a control unit configured to confirm the dummy light corresponding to each of the optical signals, and control the intensity of the confirmed dummy light based on the intensity of the optical signal corresponding to the confirmed dummy light to be output from the optical signal adjustment unit and the intensity of the confirmed dummy light to which the pre-emphasis is applied when the optical signal is not output; as well as A multiplexing unit configured to combine the dummy light with the optical signal output from the optical signal adjustment unit to output a wavelength-multiplexed optical signal.

2. The optical transmission device according to claim 1, wherein: The optical signal adjustment unit adjusts the intensities of the plurality of optical signals so that the intensities of the plurality of optical signals are uniform after transmission.

3. The optical transmission device according to claim 1 or 2, wherein: When receiving information indicating a wavelength of an optical signal to be newly input to the optical signal adjustment unit and inserted into the wavelength multiplexed optical signal, the control unit confirms the dummy light according to the information indicating the wavelength.

4. The optical transmission device according to claim 1 or 2, further comprising: an optical detection unit configured to detect wavelengths of the plurality of optical signals output from the optical signal adjustment unit, wherein: When receiving information notifying that a new optical signal is to be input to the optical signal adjustment unit and inserted into the wavelength multiplexed optical signal, the optical detection unit detects a wavelength of an optical signal whose intensity has changed by more than a predetermined value among the plurality of optical signals output from the optical signal adjustment unit, and notifies the control unit of the detected wavelength, and The control unit confirms the dummy light based on the notified wavelength.

5. The optical transmission device according to claim 1 or 2, wherein: Each of the dummy lights has a coverage band having a confirmed bandwidth, and When the optical signal is to be inserted into the cover tape, the control unit reduces the intensity of the dummy light corresponding to the cover tape according to the intensity of the optical signal to be inserted.

6. The optical transmission device according to claim 5, wherein: When the optical signal is to be inserted into the cover band, the control unit reduces the intensity of the dummy light in the cover band by a value obtained by dividing the product of the optical signal to be inserted and the bandwidth of the optical signal to be inserted by the bandwidth of the dummy light.

7. The optical transmission device according to claim 5, wherein: When the optical signal overlaps with the dummy light, the control unit: interrupting the dummy light overlapping the optical signal; increasing the intensity of the dummy light corresponding to one or more other cover bands according to the intensity of the interrupted dummy light; as well as The dummy light having the adjusted intensity is reduced according to the intensity of the optical signal to be inserted.

8. A terminal device, comprising: one or more optical transceivers; as well as an optical transmission device configured to receive input of a plurality of optical signals having different wavelengths from the one or more optical transceivers, wherein: The optical transmission device comprises: an optical signal adjustment unit configured to be capable of receiving an input of the plurality of optical signals, adjusting the intensity of each of the plurality of optical signals by applying pre-emphasis, and outputting the optical signal; a dummy light output unit configured to output a plurality of dummy lights having different wavelengths, each dummy light having an intensity to which the pre-emphasis is applied; a control unit configured to confirm the dummy light corresponding to each of the optical signals, and control the intensity of the confirmed dummy light based on the intensity of the optical signal corresponding to the confirmed dummy light to be output from the optical signal adjustment unit and the intensity of the confirmed dummy light to which the pre-emphasis is applied when the optical signal is not output; and A multiplexing unit configured to combine the dummy light with the optical signal output from the optical signal adjustment unit to output a wavelength-multiplexed optical signal.

9. An optical communication system comprising: a first terminal station configured to output a wavelength multiplexed optical signal; as well as a second terminal station, the second terminal station being configured to receive the wavelength multiplexed optical signal, wherein The first terminal station comprises: one or more optical transceivers; and an optical transmission device configured to receive input of a plurality of optical signals having different wavelengths from the one or more optical transceivers, and The optical transmission device comprises: an optical signal adjustment unit configured to be capable of receiving an input of the plurality of optical signals, adjusting the intensity of each of the plurality of optical signals by applying pre-emphasis, and outputting the optical signal; a dummy light output unit configured to output a plurality of dummy lights having different wavelengths, each dummy light having an intensity to which the pre-emphasis is applied; a control unit configured to confirm the dummy light corresponding to each of the optical signals, and control the intensity of the confirmed dummy light based on the intensity of the optical signal corresponding to the confirmed dummy light to be output from the optical signal adjustment unit and the intensity of the confirmed dummy light to which the pre-emphasis is applied when the optical signal is not output; and A multiplexing unit configured to combine the dummy light with the optical signal output from the optical signal adjustment unit to output the wavelength-multiplexed optical signal.

10. An optical communication method, comprising: adjusting the intensity of each of a plurality of optical signals having different wavelengths by applying pre-emphasis, and outputting the optical signal; outputting a plurality of dummy lights having different wavelengths, each dummy light having an intensity to which the pre-emphasis is applied; confirming the dummy light corresponding to each of the optical signals, and controlling the intensity of the confirmed dummy light based on the intensity of the optical signal based on the intensity variation in the transmission line corresponding to the confirmed dummy light and the intensity of the confirmed dummy light to which the pre-emphasis is applied when the optical signal is not output; as well as A wavelength multiplexed optical signal is outputted in which the dummy light and the optical signal having the adjusted intensity are combined.

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