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

Abstract

The present invention aims to provide an optical transmission device, in which pseudo light can be arranged according to the arrangement of optical signals. A plurality of optical signals of different frequencies arranged in a frequency grid are input to a multiplexing unit (1), and the multiplexing unit (1) multiplexes the input optical signals. A pseudo light output unit (2) identifies pseudo light (D) to be arranged in the frequency grid based on the plurality of optical signals, and outputs the pseudo light (D). A multiplexing unit (3) multiplexes the optical signal (LC) multiplexed by the multiplexing unit (1) and the pseudo light (D) output from the pseudo light output unit (2), and outputs a wavelength multiplexed optical signal L.

Description

Technical Field

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

[0002] In a submarine optical cable system, optical transmission equipment placed at a land terminal station transmits wavelength multiplexed optical signals through a submarine optical cable. In order to compensate for the optical loss caused by transmission through the submarine optical cable, multiple optical amplifiers are usually inserted into the submarine optical cable.

[0003] The wavelength multiplexed optical signal output from the transmitting side terminal station includes an optical signal (main signal) in which data addressed to the receiving terminal station is superimposed, and a pseudo light inserted to compensate for the intensity of the wavelength multiplexed optical signal according to the presence or absence of the optical signal. The intensity of the pseudo light is controlled according to the presence or absence of the optical signal. When the optical signal is added to the wavelength multiplexed optical signal, the pseudo light is controlled to reduce the intensity according to the intensity of the optical signal to be added. When the pseudo light is arranged at a wavelength overlapping with the wavelength of the optical signal to be added, the pseudo light is controlled to block it.

[0004] As a method of controlling pseudo light, there is an optical transmission device that uses a single broadband (bandwidth) pseudo light or a plurality of narrowband (channel width) pseudo lights for each sub-band (Patent Document 1). In this optical transmission device, when a new optical signal is inserted into a sub-band in which a plurality of narrowband pseudo lights are used, the intensity of the pseudo light in the sub-band is adjusted to keep the intensity of the wavelength multiplexed optical signal constant.

[0005] Reference List

[0006] Patent Literature

[0007] [Patent Document 1] Japanese Unexamined Patent Application Publication No. 2014-187671 Summary of the invention

[0008] Technical issues

[0009] When controlling pseudo light, it is desirable to determine the frequency of the pseudo light according to the arrangement (i.e., frequency distribution) of the optical signal. However, in recent years, it has become necessary to arbitrarily set the arrangement of the optical signal after starting the operation of the system. That is, when the arrangement of the optical signal is changed by adding or removing the optical signal after the operation of the system has started, a method of arranging pseudo light is required.

[0010] However, in Patent Document 1, it is not assumed that dummy light is arranged according to a change in arrangement of optical signals after operation has started.

[0011] An object of the present invention is to provide an optical transmission device in which dummy light can be arranged according to the arrangement of optical signals.

[0012] Solution to the problem

[0013] One aspect of the present invention is an optical transmission device, comprising: a first multiplexing unit, to which a plurality of optical signals of different frequencies arranged in a frequency grid are input, the first multiplexing unit being configured to multiplex the input optical signals; a pseudo-light output unit, which is configured to identify one or more pseudo-lights to be arranged in the frequency grid based on the plurality of optical signals, and output the identified one or more pseudo-lights; and a second multiplexing unit, which is configured to multiplex the plurality of optical signals multiplexed by the first multiplexing unit and the one or more pseudo-lights output from the pseudo-light output unit to output a wavelength-multiplexed optical signal.

[0014] One aspect of the present invention is a terminal station device, comprising: one or more optical transceivers; and an optical transmission device, in which a plurality of optical signals of different wavelengths are input from one or more optical transceivers, wherein the optical transmission device comprises: a first multiplexing unit, to which a plurality of optical signals of different frequencies arranged in a frequency grid are input, the first multiplexing unit being configured to multiplex the input optical signals; a pseudo-light output unit, which is configured to identify one or more pseudo-lights to be arranged in the frequency grid based on the plurality of optical signals, and output the identified one or more pseudo-lights; and a second multiplexing unit, which is configured to multiplex the plurality of optical signals multiplexed by the first multiplexing unit and the one or more pseudo-lights output from the pseudo-light output unit, to output a wavelength-multiplexed optical signal.

[0015] One aspect of the present invention is an optical communication system, comprising: 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 includes: one or more optical transceivers; and an optical transmission device, wherein a plurality of optical signals of different wavelengths are input from one or more optical transceivers, wherein the optical transmission device includes: a first multiplexing unit, a plurality of optical signals of different frequencies arranged in a frequency grid are input to the first multiplexing unit, the first multiplexing unit being configured to multiplex the input optical signals; a pseudo-light output unit, which is configured to identify one or more pseudo-lights to be arranged in the frequency grid based on the plurality of optical signals, and output the identified one or more pseudo-lights; and a second multiplexing unit, which is configured to multiplex the plurality of optical signals multiplexed by the first multiplexing unit and the one or more pseudo-lights output from the pseudo-light output unit to output the wavelength-multiplexed optical signal.

[0016] One aspect of the present invention is an optical communication method, comprising: multiplexing a plurality of optical signals of different frequencies arranged in a frequency grid; identifying one or more pseudo lights to be arranged in the frequency grid based on the plurality of optical signals, and outputting the identified one or more pseudo lights; and multiplexing the plurality of multiplexed optical signals and the one or more pseudo lights to output a wavelength multiplexed optical signal.

[0017] Advantageous Effects of the Invention

[0018] According to the present invention, it is possible to provide an optical transmission device in which dummy light can be arranged according to the arrangement of optical signals. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] 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;

[0020] Figure 2 is a view schematically showing a configuration of a terminal station according to a first exemplary embodiment;

[0021] Figure 3 is a view showing an example of a frequency grid;

[0022] Figure 4 is a diagram showing an example of an optical signal and pseudo light arranged within a frequency grid;

[0023] Figure 5 is a view showing an example of arranging a plurality of optical signals and a plurality of dummy lights within one frequency slot;

[0024] Figure 6 is a view schematically showing a configuration of an optical transmission device according to a first exemplary embodiment;

[0025] Figure 7 is a view showing the configuration of the optical transmission device according to the first exemplary embodiment in more detail;

[0026] Figure 8 is a flowchart showing the operation of the optical transmission device according to the first exemplary embodiment;

[0027] Fig. 9 is a view showing the arrangement of optical signals included in a wavelength multiplexed optical signal;

[0028] Fig.10 is a view showing the arrangement of selected pseudo lights;

[0029] Fig.11 is a flowchart showing the operation of the optical transmission device according to the first exemplary embodiment;

[0030] Fig.12is a view showing an optical signal to be added;

[0031] Fig.13 is a view showing pseudo light to be blocked;

[0032] Fig.14 is a diagram showing a wavelength multiplexed optical signal after an optical signal has been added;

[0033] Fig.15 is a flowchart showing the operation of the optical transmission device according to the first exemplary embodiment;

[0034] Fig.16 is a diagram showing an optical signal to be removed;

[0035] Fig.17 is a view showing additional pseudo light;

[0036] Fig.18 is a view showing a wavelength multiplexed optical signal after an optical signal has been removed;

[0037] Fig.19 is a view schematically showing a configuration of an optical transmission device according to a second exemplary embodiment;

[0038] Fig. 20 is a view schematically showing a configuration of an optical transmission device according to a third exemplary embodiment; and

[0039] Fig.21 is a flowchart showing the operation of the optical transmission device according to the third exemplary embodiment. DETAILED DESCRIPTION

[0040] Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference numerals and redundant description will be appropriately omitted.

[0041] First exemplary embodiment

[0042] An optical transmission device 100 according to a first exemplary embodiment will be described. 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. Here, it is assumed that the optical transmission device 100 is installed at a terminal station on land included in the optical communication system 1000 constituting a submarine optical network.

[0043] Figure 1Schematically shows an example of a configuration of an optical communication system 1000 according to a first exemplary embodiment. 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.

[0044] 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 the notification signal INF.

[0045] The terminal station TS1 and the terminal station TS2 are connected by a transmission line, which is placed on land or on the seabed and includes an optical fiber F for transmitting an optical signal. Here, 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 defined as the transmission line TL1. The transmission line for transmitting an optical signal from the terminal station TS2 to the terminal station TS1 is defined as the transmission line TL2. It should be noted that other equipment such as a submarine optical branching equipment for ADD / DROP optical signals can be inserted into the transmission lines TL1 and TL2 as needed.

[0046] One or more optical amplifiers AMP for amplifying optical signals are inserted in each of the transmission lines TL1 and TLE2.

[0047] In this exemplary embodiment, the terminal station TS1 outputs the wavelength multiplexed optical signal L (first wavelength multiplexed optical signal) to the terminal station TS2 through the transmission line TL1. In the wavelength multiplexed optical signal L, optical signals of one or more wavelengths (channels) to be transmitted are wavelength multiplexed. The terminal station TS1 outputs the wavelength multiplexed optical signal LL (second wavelength multiplexed optical signal) to the terminal station TS2 through the transmission line TL2.

[0048] Then, the configuration of the terminal station TS1 according to the present exemplary embodiment will be described.Similar to a general terminal station, the terminal station TS1 has an optical transmission device and a plurality of optical transponders. Figure 2 The configuration of the terminal station TS1 according to the first exemplary embodiment is schematically shown. Figure 2 The following example is shown, in which optical transceivers TPD11, TPD12, TPD21 and TPD22 are connected to the optical transmission device 100 arranged in the terminal station TS1. In this configuration, the optical transmission device 100 and the optical transceivers TPD11, TPD12, TPD21 and TPD22 constitute the terminal station device TA arranged in the terminal station TS1.

[0049] The optical transceivers TPD11, TPD12, TPD21, and TPD22 are connected to the optical transmission device 100 through, for example, optical fibers, and can exchange optical signals with other terminal stations via the optical transmission device 100. The multiple optical transceivers disposed in the terminal station do not need to be the same optical transceivers, and optical transceivers with different functions or optical transceivers from different manufacturers can be used as needed.

[0050] In this example, the optical transceivers TPD11, TPD12, TPD21, and TPD22 respectively output optical signals L11, L12, L21, and L22 to the optical transmission device 100. The optical signals L11, L12, L21, and L22 each include an optical signal having a frequency of 1 or more.

[0051] The optical transmission device 100 multiplexes the optical signals L11, L12, L21, and L22, and further multiplexes the dummy light into the multiplexed optical signal to generate a wavelength multiplexed optical signal L. The optical transmission device 100 outputs the wavelength multiplexed optical signal L to the transmission line TL1.

[0052] In this configuration, optical transceivers TPD11 and TPD12 correspond to the frequency grid G1 included in the wavelength multiplexed optical signal L, and optical transceivers TPD21 and TPD22 correspond to the frequency grid G2. Thus, optical signals L11 and L12 are optical signals corresponding to the frequency grid G1, and optical signals L21 and L22 are optical signals corresponding to the frequency grid G2. The frequency grid will be described in detail below.

[0053] Frequency grids G1 and G2 can be allocated to different users. In this case, each user can insert or remove optical signals in the allocated frequency grid as needed.

[0054] Here, the optical signal and dummy light included in the wavelength multiplexed optical signal L will be specifically described. Generally, a plurality of frequency grids are set in the wavelength multiplexed optical signal L. Here, the frequency grid refers to a set of center frequencies that can be used as optical signal channels, as specified by ITU-T G 694.1.

[0055] Here, for clarity of explanation, "bandwidth" indicates the width of a frequency band or wavelength band between a lower limit value and an upper limit value, and "band" indicates a frequency range or wavelength range having a predetermined "bandwidth" centered on a predetermined center wavelength or a "bandwidth" between an upper limit value and a lower limit value. In other words, "bandwidth" can be quantitatively defined by a numerical value, and "bandwidth" is used to identify a frequency range or wavelength range having a predetermined "bandwidth" set at different positions, for example, a first band or a second band.

[0056] Figure 3 An example of a frequency grid is shown. Figure 3 , the frequency grid GA and the frequency grid GB on the higher frequency side than the frequency grid GA are shown as examples. In this embodiment, although there is a gap between the frequency grid GA and the frequency grid GB to make the drawing easier to view, it should be understood that the frequency grid GA and the frequency grid GB may be in contact with each other. For example, when there is a band that does not belong to either the frequency grid GA or the frequency grid GB, a guard band may be arranged in the band.

[0057] The frequency grid GA includes m (m is a positive integer) center frequencies f that can be used as optical signal channels. A1 to f Am In the frequency grid GA, set the center frequency f A1 to f Am The center bandwidth W A The frequency gap S A1 To S Am The frequency grid GB includes n (n is a positive integer) center frequencies f that can be used as optical signal channels. B1 to f Bn In the frequency grid GB, set the center frequency f B1 to f Bn The central bandwidth W B The frequency gap S B1 To S Bn As specified by ITU-T G 694.1, the frequency slots are set so that there are no overlapping bands (frequency ranges). The bandwidth of a frequency slot is referred to below as slot width.

[0058] Frequency gap S A1 To S Am The gap width W A Sum frequency gap S B1 To S Bn The gap width W B Can be the same or different. For example, the gap width W A and gap width W B It can be the same 50GHz, or the slot width W A can be 50GHz, the gap width W B It can be 37.5GHz.

[0059] Then, the optical signal and the pseudo light arranged in the frequency grid will be described. Figure 4 Shown is arranged in Figure 3 An example of an optical signal and a pseudo light within a frequency grid shown in . In this example, one optical signal or one pseudo light is placed in one frequency slot, and the optical signal and the pseudo light placed in the same frequency slot have the same bandwidth.

[0060] In this example, in the frequency grid GA, the optical signal L A2 Arranged in frequency slot S A2 In the middle, and the pseudo light D A1 , D A3 and D AM Arranged in frequency slot S A1 , S A3 and S AM Although the frequency gap S is omitted A4 To S A(m-1) display, but optical signals or pseudo-light are also arranged in each of these frequency slots.

[0061] In the frequency grid GB, the optical signal L B1 and L B3 Arranged in frequency slot S B1 and S B3 In the middle, and the pseudo light D B2 and D Bn Arranged in frequency slot S B2 and S Bn Although the frequency gap S is omitted B4 To S B(n-1) display, but optical signals or pseudo-light are also arranged in each of these frequency slots.

[0062] exist Figure 4 The arrangement of the optical signals and the dummy light shown in FIG. 1 is merely an example, and it should be understood that the number of optical signals, the number of dummy lights, and the arrangement of the optical signals and the dummy light may be appropriately changed as required.

[0063] Although an example in which one optical signal or one dummy light is arranged in one frequency slot has been described herein, a plurality of optical signals and a plurality of dummy lights may be arranged. Figure 5 shows a case where multiple optical signals and multiple pseudo lights are arranged in a frequency slot S A1 In the frequency slot S A1 For example, eight channels are set starting from the low frequency side. In this case, the bandwidth of each channel is W AC .

[0064] Pseudo light D A1_1 , D A1_3 and D A1_6 are arranged in the first, third and sixth channels respectively. The optical signal L A1_2 , L A1_4 , L A1_5 , L A1_7 and L A1_8 are arranged in the second, fourth, fifth, sixth and eighth channels respectively. In this way, a plurality of channels can be set in one frequency slot, and the optical signal and the pseudo light can be arranged in each channel as needed.

[0065] Next, the optical transmission device 100 according to the first exemplary embodiment will be described. Figure 6 The configuration of an optical transmission device 100 according to the first exemplary embodiment is schematically shown. Figure 7 The configuration of the optical transmission device 100 according to the first exemplary embodiment is shown in more detail. The optical transmission device 100 includes a multiplexing unit 1, a dummy light output unit 2, and a multiplexing unit 3. Optical signals L11, L12, L21, and L22 are input to the optical transmission device 100.

[0066] The multiplexing unit 1 (first multiplexing unit) includes multiplexers 11 to 13. The multiplexers 11 to 13 are configured as wavelength selective switches (WSS), for example.

[0067] The multiplexer 11 multiplexes the optical signals L11 and L12 corresponding to the frequency grid G1 , and outputs the multiplexed optical signal L10 to the multiplexer 13 .

[0068] The multiplexer 12 multiplexes the optical signals L21 and L22 corresponding to the frequency grid G2 , and outputs the multiplexed optical signal L20 to the multiplexer 13 .

[0069] The multiplexer 13 multiplexes the optical signal L10 and the optical signal L20 , and outputs the multiplexed optical signal LC to the multiplexing unit 3 .

[0070] The pseudo light output unit 2 includes a pseudo light source 21 and a frequency selection unit 22. The pseudo light source 21 outputs light DL in a predetermined frequency range. The frequency selection unit 22 selects a plurality of bands of light to be output as pseudo light from the light in the predetermined frequency range, and outputs the selected light as pseudo light. For example, the frequency selection unit 22 can be configured as a wavelength selective switch (WSS). Figure 6 and Figure 7 , the dummy light output from the dummy light output unit 2 is collectively indicated by a reference symbol D.

[0071] The multiplexing unit 3 (second multiplexing unit) multiplexes the optical signal LC and the dummy light D, and outputs a wavelength-multiplexed optical signal L to the transmission line TL1. The multiplexing unit 3 is configured as, for example, an optical coupler.

[0072] Then, the operation of the optical transmission device 100 will be described. The following description will be based on reference Figure 4 The frequency grid. So, for example, Figure 4 The optical signal L A2 Can correspond to reference Figure 2 , Figure 6 , Figure 7 Any one of the optical signals L11 and L12 described above. For example, Figure 4 The optical signal LB1 and L B3 Can correspond to reference Figure 2 , Figure 6 , Figure 7 Any one of the optical signals L21 and L22 described above.

[0073] Figure 8 is a flowchart showing the operation of the optical transmission device 100 according to the first exemplary embodiment. The management server 1001 outputs a notification signal INF for notifying the optical transmission device 100 of an optical signal included in each frequency grid. The notification signal INF includes, for example, information indicating the center frequency of the optical signal.

[0074] The notification signal INF may include information indicating the wavelength grid, such as information indicating a center frequency constituting the wavelength grid, information on bandwidths of slots constituting the wavelength grid, and a part or all of a band in which the wavelength grid is provided.

[0075] The management server 1001 can receive information indicating the center frequency and wavelength grid of the optical signal from the outside and store the information therein, and can generate the notification signal INF based on the stored information. If the management server 1001 can read the setting information (output wavelength) of the optical transceiver, the notification signal INF can be generated based on the read setting information. In addition, if the management server 1001 can input (write, update or change) the setting information to the optical transceiver, the notification signal INF can be generated based on the input setting information.

[0076] Fig. 9 1 shows the arrangement of optical signals included in the wavelength multiplexed optical signal L. That is, Fig. 9 The frequency distribution of the optical signal LC output from the multiplexing unit 1 is shown.

[0077] Step SA11

[0078] The frequency selection unit 22 receives the notification signal INF.

[0079] Step SA12

[0080] The frequency selection unit 22 refers to the table TAB1 stored based on the notification signal INF, and sets the frequency selectively output from the light DL from the pseudo light source 21. Here, the frequency selectively output from the light DL corresponds to the center frequency or frequency grid of the optical signal included in the wavelength multiplexed optical signal L. The table TAB1 can store the center frequency and bandwidth of the pseudo light to be output according to the center frequency or frequency grid of the optical signal.

[0081] If the notification signal INF directly indicates the frequency to be selectively output from the light DL to the frequency selection unit 22 , the table TAB1 does not need to be stored, and the frequency to be selectively output from the light DL may be set based on the notification signal INF.

[0082] Fig.10 The arrangement of the selected pseudo light is shown. That is, Fig.10 FIG. 2 shows the frequency distribution of the pseudo light D output from the frequency selection unit 22. Fig.10 As shown in , the center frequency and bandwidth of the pseudo light set in the band of the frequency grid GA are different from the center frequency and bandwidth of the pseudo light set in the band of the frequency grid GB. The frequency selection unit 22 sets the different center frequency intervals and bandwidths between the band GA and the band GB as the frequencies to be selectively output in the light DL.

[0083] Step SA13

[0084] The frequency selection unit 22 outputs a frequency that does not overlap with an optical signal of a frequency set to be selectively output in the light DL. For example, the frequency selection unit 22 identifies a frequency slot in which an optical signal is not arranged, selects a center frequency corresponding to the identified frequency slot, and outputs the selected center frequency as a pseudo light. It should be noted that the frequency selection unit 22 can obtain information on a frequency slot in which an optical signal is not arranged from the management server 1001. When the optical transmission device 100 may include an optical monitoring unit not shown in the figure, and the optical monitoring unit monitors the frequency and intensity of the optical signal, the frequency slot in which the optical signal is not arranged can be identified based on the monitoring result of the optical monitoring unit.

[0085] Step SA14

[0086] Multiplexing unit 3 multiplexes as Fig. 9 The optical signal LC arranged as shown in FIG. Fig.10 Thus, the pseudo light D arranged as shown in FIG. Figure 4 The wavelength multiplexed optical signal L is shown in .

[0087] As described above, according to the present configuration, the optical signal and the dummy light can be arranged in the frequency grid according to the setting of the frequency grid.

[0088] Next, the operation of the optical transmission device 100 when a new optical signal is added to the wavelength-multiplexed optical signal L will be described. Fig.11 is a flowchart showing the operation of the optical transmission device 100 according to the first exemplary embodiment. In this case, an additional optical signal may be output from an optical transceiver newly connected to the optical transmission device 100, or may be additionally output from an optical transceiver already connected to the optical transmission device 100.

[0089] To notify that a new optical signal is added, the management server 1001 outputs a notification signal INF to the optical transmission device 100. At this time, the notification signal INF may include information indicating the center frequencies of all optical signals including the optical signal to be added, or may include information indicating only the center frequency of the optical signal to be added.

[0090] Step SA21

[0091] The frequency selection unit 22 receives the notification signal INF.

[0092] Step SA22

[0093] The frequency selection unit 22 refers to the table TAB1 stored based on the notification signal INF, and identifies a frequency slot corresponding to the center frequency of the optical signal to be added. Fig.12 The optical signal to be added is shown. Fig.12 shows a central frequency f A3 The optical signal L A3 The frequency slot S is added to the frequency grid GA A3 .

[0094] Step SA23

[0095] The frequency selection unit 22 blocks the A3 Pseudo-light D A3 . Fig.13 The false light D to be blocked is shown A3 .

[0096] Step SA24

[0097] After that, the optical signal L A3 is output, and the optical signal L A3 is added to the wavelength multiplexed optical signal L. Fig.14 shows that the optical signal L has been added A3 The wavelength multiplexed optical signal L follows.

[0098] As described above, according to the present configuration, even if a new optical signal is added, the pseudo light corresponding to the optical signal to be added can be blocked to prevent the added optical signal from overlapping with the pseudo light. As a result, even after the optical transmission device is installed at the terminal station and starts its operation, appropriate pseudo light can be flexibly output according to the change of the optical signal to be transmitted.

[0099] Next, the operation of the optical transmission device 100 when the optical signal is removed from the wavelength-multiplexed optical signal L will be described. Fig.151 is a flowchart showing the operation of the optical transmission device 100 according to the first exemplary embodiment. In this case, the optical signal to be removed may be an optical signal output from the optical transceiver removed from the optical transmission device 100, or an optical signal to be blocked included in a plurality of optical signals having different center frequencies output from the optical transceiver connected to the optical transmission device 100.

[0100] In order to notify the removal of the optical signal from the wavelength multiplexed optical signal L, the management server 1001 outputs a notification signal INF to the optical transmission device 100. At this time, the notification signal INF may include information indicating the center frequency of an optical signal different from the optical signal to be removed, or may include information indicating only the center frequency of the optical signal to be removed.

[0101] Step SA31

[0102] The frequency selection unit 22 receives the notification signal INF.

[0103] Step SA32

[0104] The frequency selection unit 22 refers to the table TAB1 stored based on the notification signal INF, and identifies the slot in which the optical signal to be removed is arranged. Fig.16 The optical signal to be removed is shown. Fig.16 shows a frequency gap S in which the frequency grid GB is removed. B1 The optical signal L arranged in B1 .

[0105] Step SA33

[0106] In blocking the optical signal L B1 After that, the frequency selection unit 22 adds the B1 Pseudo-light D B1 . Fig.17 The added pseudo light D B1 .

[0107] Step SA34

[0108] Thus, the optical signal L is removed from the wavelength multiplexed optical signal L B1 , and add the empty frequency slot S B1 The corresponding pseudo light D B1 . Fig.18 It shows that the optical signal L has been removed B1 The wavelength multiplexed optical signal L follows.

[0109] As described above, according to the present configuration, even when an optical signal is removed from a wavelength multiplexed optical signal, the output of the wavelength multiplexed optical signal can be maintained by adding a dummy light corresponding to the removed optical signal. As a result, even when the optical transmission device is installed at a terminal station and starts its operation, appropriate dummy light can be flexibly output according to the change of the optical signal to be transmitted.

[0110] You can set the reference arbitrarily Figure 3 and Figure 4 The number and width of the frequency grid, and the number and width of the frequency slots arranged in the frequency grid. Thus, for example, when executing Figure 8 When the setting of the frequency grid or the frequency slot is changed by the operation described in the above, the optical signal and the pseudo light can be easily rearranged according to the changed frequency grid or the frequency slot.

[0111] Second exemplary embodiment

[0112] An optical transmission device 200 according to a second exemplary embodiment will be described. Fig.19 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 control unit 4 is added to the optical transmission device 100 according to the first exemplary embodiment.

[0113] The control unit 4 receives the notification signal INF from the management server 1001 , and the frequency selection unit 22 outputs a control signal C1 in response to the notification signal INF to control the wavelength selection operation of the frequency selection unit 22 .

[0114] In the present exemplary embodiment, notification signal INF output from management server 1001 to control unit 4 includes port information specifying WSS ports constituting multiplexers 11 to 13 included in multiplexing unit 1. Port information is information indicating a frequency transmitted through each port.

[0115] The control unit 4 stores a table TAB2 indicating the corresponding relationship between the WSS ports constituting the multiplexers 11 to 13 and the optical signals, or the corresponding relationship between the WSS ports and the frequency slots. The control unit 4 refers to the table TAB2 according to the port information indicated by the notification signal INF, and identifies the center frequency of the optical signal corresponding to the given port information. Then, the control unit 4 notifies the frequency selection unit 22 of the center frequency of the optical signal through the control signal C1.

[0116] According to this configuration, as in the case of the optical transmission device 100 according to the first exemplary embodiment, the optical signal and the dummy light can be arranged in the frequency grid according to the setting of the frequency grid. In addition, it should be understood that according to this configuration, the optical signal can be added and removed in the same manner as in the optical transmission device 100 according to the first exemplary embodiment.

[0117] In this configuration, the control unit 4 may provide a control signal to the multiplexing unit 1 to adjust the corresponding intensity of the optical signal multiplexed by the multiplexing unit 1. In this case, when a new optical signal is added, the intensity of the added optical signal may be adjusted based on the intensity of the pseudo light to be blocked.

[0118] Third exemplary embodiment

[0119] An optical transmission device 300 according to a third exemplary embodiment will be described. Fig. 20 The configuration of an optical transmission device 300 according to the third exemplary embodiment is schematically shown. The optical transmission device 300 has a configuration in which an optical monitoring unit 4 is added to the optical transmission device 200 according to the second exemplary embodiment.

[0120] In the present configuration, the multiplexing unit 3 branches a part of the input optical signal LC, and outputs the branched part of the optical signal LC to the optical monitoring unit 5 .

[0121] Fig.21 is a flowchart showing the operation of the optical transmission device 300 according to the third exemplary embodiment. Fig.21 in Figure 8 Step SA41 is added between step SA11 and step SA12 in the above. Steps SA11 to SA14 are the same as Figure 8 Same as in.

[0122] The optical monitoring unit 5 detects the optical signal LC input by the light receiving element (such as a photodiode), and can monitor the frequency and intensity of the optical signal included in the optical signal LC. The optical monitoring unit 5 outputs a monitoring signal MON indicating the monitoring result of the optical signal LC to the control unit 4 ( Fig.21 41 in step 4).

[0123] The control unit 4 may refer to the monitor signal MON and set the frequency arrangement of the pseudo light according to the center frequency of the optical signal included in the optical signal LC. Fig.21 The control unit 4 notifies the setting of the frequency arrangement of the pseudo light through the control signal C1.

[0124] Therefore, with Figure 8In the same manner as in step SA13 and step SA14, pseudo light corresponding to the arrangement of the optical signal may be output from the frequency selection unit 22.

[0125] According to the present configuration, the center frequency of the optical signal can be autonomously identified without receiving the notification signal INF including the center frequency of the optical signal and the port information of the multiplexing unit 1 from the management server 1001. Also in this case, a signal for identifying the center frequency of the optical signal and instructing the start of the operation to output pseudo light can be received from an external device such as the management server 1001, and the operation can be started in response to the received signal. Fig.21 The operation of the optical transmission device 300 shown in FIG.

[0126] Other Example Embodiments

[0127] The present invention is not limited to the above-described exemplary embodiments, and may be modified as necessary without departing from the spirit and scope of the present invention. For example, in the above-described exemplary embodiments, in order to simplify the description, although it has been described that a pseudo light or an optical signal is arranged in a slot, this is only an example. Figure 5 As described above, a plurality of channels may be arranged in one frequency slot, and an optical signal or pseudo light may be arranged in each channel. In this case, the optical signal or pseudo light may be arranged based on the center frequency of the optical signal or pseudo light of each channel, as in the case where one pseudo light or one optical signal is arranged in one slot.

[0128] Although two frequency grids have been described in the above exemplary embodiments, the wavelength multiplexed optical signal may include three or more frequency grids.

[0129] The number of optical transceivers connected to the optical transmission device is only an example, and it should be understood that any number of optical transceivers may be connected to the optical transmission device.

[0130] In the above-described exemplary embodiments, although it has been described that the management server is disposed separately from the terminal station, the management server may be disposed as a terminal station monitoring device disposed in the terminal station.

[0131] Figure 8 The operation of the optical transmission device shown in can be similarly performed even if no optical transceiver is connected to the optical transmission device, or even if the optical transceiver does not output an optical signal.

[0132] For example, all or part of the exemplary embodiments disclosed above may be described as, but not limited to, the following supplementary notes.

[0133] (Supplementary Note 1) An optical transmission device includes: a first multiplexing unit, to which a plurality of optical signals of different frequencies arranged in a frequency grid are input, the first multiplexing unit being configured to multiplex the input optical signals; a pseudo-light output unit, the pseudo-light output unit being configured to identify one or more pseudo-lights to be arranged in the frequency grid based on the plurality of optical signals and output the identified one or more pseudo-lights; and a second multiplexing unit, the second multiplexing unit being configured to multiplex the plurality of optical signals multiplexed by the first multiplexing unit and the one or more pseudo-lights output from the pseudo-light output unit to output a wavelength-multiplexed optical signal.

[0134] (Supplementary Note 2) The optical transmission device according to Supplementary Note 1, wherein a signal indicating frequencies of a plurality of optical signals is received, and based on the received signal, the frequency of the one or more pseudo lights is identified.

[0135] (Supplementary Note 3) The optical transmission device according to Supplementary Note 1 further includes a control unit configured to control a pseudo light output unit, wherein the control unit: receives information indicating ports respectively corresponding to a plurality of optical signals disposed in the first multiplexing unit; identifies frequencies of the plurality of optical signals based on the information indicating the ports; identifies frequencies of one or more pseudo lights based on the frequencies of the plurality of optical signals; and controls the pseudo light output unit to output one or more pseudo lights of the identified frequencies.

[0136] (Supplementary Note 4) The optical transmission device according to Supplementary Note 3 further includes an optical monitoring unit, which is configured to monitor the intensity of the multiple optical signals multiplexed by the first multiplexing unit and output a signal indicating the monitoring result to the control unit, wherein the control unit: identifies the frequencies of the multiple optical signals multiplexed by the first multiplexing unit based on the signal indicating the monitoring result; identifies the frequencies of one or more pseudo lights based on the frequencies of the multiple optical signals; and controls the pseudo light output unit to output the one or more pseudo lights of the identified frequencies.

[0137] (Supplementary Note 5) An optical transmission device according to any one of Supplementary Notes 1 to 4, wherein, when an optical signal having a frequency different from the frequencies of a plurality of optical signals is additionally input to the first multiplexing unit, the pseudo-light output unit identifies pseudo-light corresponding to the frequency of the optical signal to be added from one or more pseudo-lights, and stops outputting the identified pseudo-light.

[0138] (Supplementary Note 6) An optical transmission device according to any one of Supplementary Notes 1 to 5, wherein, when there is an optical signal that is blocked and not input to the first multiplexing unit among a plurality of optical signals input to the first multiplexing unit, the pseudo-light output unit identifies pseudo-light corresponding to the frequency of the optical signal to be blocked, and newly outputs the identified pseudo-light.

[0139] (Supplementary Note 7) An optical transmission device according to any one of Supplementary Notes 1 to 6, wherein a plurality of frequency slots having a predetermined width are arranged in a frequency grid, and in each of the plurality of frequency slots, an optical signal or a pseudo light is arranged, or one or more optical signals and one or more pseudo lights are arranged without overlapping.

[0140] (Supplementary Note 8) A terminal station device comprises: one or more optical transceivers; and an optical transmission device, wherein a plurality of optical signals of different wavelengths are input from one or more optical transceivers, wherein the optical transmission device comprises: a first multiplexing unit, to which a plurality of optical signals of different frequencies arranged in a frequency grid are input, the first multiplexing unit being configured to multiplex the input optical signals; a pseudo-light output unit, the pseudo-light output unit being configured to identify one or more pseudo-lights to be arranged in the frequency grid based on the plurality of optical signals, and output the identified one or more pseudo-lights; and a second multiplexing unit, the second multiplexing unit being configured to multiplex the plurality of optical signals multiplexed by the first multiplexing unit and the one or more pseudo-lights output from the pseudo-light output unit, to output a wavelength-multiplexed optical signal.

[0141] (Supplementary Note 9) The terminal station device according to Supplementary Note 8, wherein a signal indicating frequencies of a plurality of optical signals is received, and based on the received signal, the frequency of the one or more pseudo lights is identified.

[0142] (Supplementary Note 10) The terminal station device according to Supplementary Note 8 further includes a control unit configured to control a pseudo light output unit, wherein the control unit: receives information indicating ports respectively corresponding to a plurality of optical signals disposed in the first multiplexing unit; identifies frequencies of the plurality of optical signals based on the information indicating the ports; identifies frequencies of one or more pseudo lights based on the frequencies of the plurality of optical signals; and controls the pseudo light output unit to output one or more pseudo lights of the identified frequencies.

[0143] (Supplementary Note 11) The terminal station device according to Supplementary Note 10 further includes an optical monitoring unit, which is configured to monitor the intensity of the multiple optical signals multiplexed by the first multiplexing unit and output a signal indicating the monitoring result to the control unit, wherein the control unit: identifies the frequencies of the multiple optical signals multiplexed by the first multiplexing unit based on the signal indicating the monitoring result; identifies the frequencies of one or more pseudo lights based on the frequencies of the multiple optical signals; and controls the pseudo light output unit to output one or more pseudo lights of the identified frequencies.

[0144] (Supplementary Note 12) A terminal station device according to any one of Supplementary Notes 8 to 11, wherein, when an optical signal having a frequency different from that of a plurality of optical signals is additionally input to the first multiplexing unit, the pseudo-light output unit identifies pseudo-light corresponding to the frequency of the optical signal to be added from one or more pseudo-lights, and stops outputting the identified pseudo-light.

[0145] (Supplementary Note 13) A terminal station device according to any one of Supplementary Notes 8 to 12, wherein, when there is an optical signal that is blocked and not input to the first multiplexing unit among a plurality of optical signals input to the first multiplexing unit, the pseudo-light output unit identifies pseudo-light corresponding to the frequency of the optical signal to be blocked, and newly outputs the identified pseudo-light.

[0146] (Supplementary Note 14) A terminal station device according to any one of Supplementary Notes 8 to 13, wherein a plurality of frequency slots having a predetermined width are arranged in a frequency grid, and in each of the plurality of frequency slots, an optical signal or a pseudo light is arranged, or one or more optical signals and one or more pseudo lights are arranged without overlapping.

[0147] (Supplementary Note 15) An optical communication system, comprising: a first terminal station, the first terminal station is configured to output a wavelength-multiplexed optical signal; and a second terminal station, the second terminal station 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, wherein a plurality of optical signals of different wavelengths are input from one or more optical transceivers, wherein the optical transmission device comprises: a first multiplexing unit, a plurality of optical signals of different frequencies arranged in a frequency grid are input to the first multiplexing unit, the first multiplexing unit is configured to multiplex the input optical signals; a pseudo-light output unit, the pseudo-light output unit is configured to identify one or more pseudo-lights to be arranged in the frequency grid based on the plurality of optical signals and output the identified one or more pseudo-lights; and a second multiplexing unit, the second multiplexing unit is configured to multiplex the plurality of optical signals multiplexed by the first multiplexing unit and the one or more pseudo-lights output from the pseudo-light output unit to output the wavelength-multiplexed optical signal.

[0148] (Supplementary Note 16) The optical communication system according to Supplementary Note 15, wherein a signal indicating frequencies of the plurality of optical signals is received, and based on the received signal, the frequency of the one or more pseudo lights is identified.

[0149] (Supplementary Note 17) The optical communication system according to Supplementary Note 15 further includes a control unit configured to control a pseudo light output unit, wherein the control unit: receives information indicating ports respectively corresponding to a plurality of optical signals disposed in the first multiplexing unit; identifies frequencies of the plurality of optical signals based on the information indicating the ports; identifies frequencies of one or more pseudo lights based on the frequencies of the plurality of optical signals; and controls the pseudo light output unit to output one or more pseudo lights of the identified frequencies.

[0150] (Supplementary Note 18) The optical communication system according to Supplementary Note 17 further includes an optical monitoring unit, which is configured to monitor the intensity of the multiple optical signals multiplexed by the first multiplexing unit and output a signal indicating the monitoring result to the control unit, wherein the control unit: identifies the frequencies of the multiple optical signals multiplexed by the first multiplexing unit based on the signal indicating the monitoring result; identifies the frequencies of one or more pseudo lights based on the frequencies of the multiple optical signals; and controls the pseudo light output unit to output one or more pseudo lights of the identified frequencies.

[0151] (Supplementary Note 19) An optical communication system according to any one of Supplementary Notes 15 to 18, wherein, when an optical signal having a frequency different from the frequencies of a plurality of optical signals is additionally input to the first multiplexing unit, the pseudo-light output unit identifies pseudo-light corresponding to the frequency of the optical signal to be added from one or more pseudo-lights, and stops outputting the identified pseudo-light.

[0152] (Supplementary Note 20) An optical communication system according to any one of Supplementary Notes 15 to 19, wherein, when there is an optical signal that is blocked and not input to the first multiplexing unit among a plurality of optical signals input to the first multiplexing unit, the pseudo-light output unit identifies pseudo-light corresponding to the frequency of the optical signal to be blocked, and newly outputs the identified pseudo-light.

[0153] (Supplementary Note 21) An optical communication system according to any one of Supplementary Notes 15 to 20, wherein a plurality of frequency slots having a predetermined width are arranged in a frequency grid, and in each of the plurality of frequency slots, an optical signal or a pseudo light is arranged, or one or more optical signals and one or more pseudo lights are arranged without overlapping.

[0154] (Supplementary Note 22) An optical communication method, comprising: multiplexing a plurality of optical signals of different frequencies arranged in a frequency grid; identifying one or more pseudo lights to be arranged in the frequency grid based on the plurality of optical signals and outputting one or more identified pseudo lights; and multiplexing the multiplexed plurality of optical signals and the one or more pseudo lights to output a wavelength-multiplexed optical signal.

[0155] (Supplementary Note 23) The optical communication method according to Supplementary Note 22, wherein a signal indicating frequencies of the plurality of optical signals is received, and the frequencies of the one or more pseudo lights are identified based on the received signal.

[0156] (Supplementary Note 24) An optical communication method according to Supplementary Note 22, wherein a plurality of optical signals are multiplexed by a multiplexing unit, information indicating ports respectively corresponding to the plurality of optical signals arranged in the multiplexing unit is received, and frequencies of the plurality of optical signals are identified based on the information indicating the ports; frequencies of one or more pseudo lights are identified based on the frequencies of the plurality of optical signals, and the one or more pseudo lights of the identified frequencies are output.

[0157] (Supplementary Note 25) An optical communication method according to Supplementary Note 24, wherein the intensities of the multiple optical signals multiplexed are monitored to output a signal indicating a monitoring result, the frequencies of the multiple optical signals multiplexed are identified based on the signal indicating the monitoring result, the frequencies of one or more pseudo lights are identified based on the frequencies of the multiple optical signals, and the one or more pseudo lights of the identified frequencies are output.

[0158] (Supplementary Note 26) An optical communication method according to any one of Supplementary Notes 22 to 25, wherein, when an optical signal having a frequency different from that of a plurality of optical signals is added, pseudo light corresponding to the frequency of the optical signal to be added is identified from one or more pseudo lights, and output of the identified pseudo light is stopped.

[0159] (Supplementary Note 27) The optical communication method according to any one of Supplementary Notes 22 to 26, wherein, when an optical signal to be blocked exists among a plurality of optical signals, false light corresponding to a frequency of the optical signal to be blocked is identified and the identified false light is newly output.

[0160] (Supplementary Note 28) An optical communication method according to any one of Supplementary Notes 22 to 27, wherein a plurality of frequency slots having a predetermined width are arranged in a frequency grid, and in each of the plurality of frequency slots, an optical signal or a pseudo light is arranged, or one or more optical signals and one or more pseudo lights are arranged without overlapping.

[0161] Although the present invention has been particularly shown and described with reference to exemplary embodiments thereof, the present invention is not limited to these exemplary embodiments. It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention.

[0162] This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-16416, filed on January 31, 2019, the disclosure of which is incorporated herein by reference in its entirety.

[0163] Reference numerals list

[0164] 1.3 Multiplexing unit

[0165] 2 Pseudo light output unit

[0166] 4 Control unit

[0167] 5 Optical monitoring unit

[0168] 11 to 13 Multiplexer

[0169] 21 Pseudo light source

[0170] 22 Frequency selection unit

[0171] 100, 200, 300 optical transmission equipment

[0172] 1000 Optical Communication Systems

[0173] 1001 Management Server

[0174] AMP Optical Amplifier

[0175] C1 control signal

[0176] D False Light

[0177] DL Light

[0178] F Fiber Optic

[0179] G1, G2, GA, GB frequency grids

[0180] INF Notification Signal

[0181] L, LL wavelength multiplexed optical signal

[0182] L10 to L12, L20 to L22, LC optical signal

[0183] MON monitoring signal

[0184] TA Terminal Equipment

[0185] TAB1, TAB2 tables

[0186] TL1, TL2 transmission lines

[0187] TPD11, TPD12, TPD21, TPD22 Optical Transceivers

[0188] TS1, TS2 Terminal Station

Claims

1. An optical transmission device, comprising: a first multiplexing unit, to which a plurality of optical signals of different frequencies arranged in a frequency grid are input, the first multiplexing unit being configured to multiplex the input optical signals; a pseudo light output unit configured to receive a signal indicating frequencies and bandwidths constituting the frequency grid in which the plurality of optical signals are arranged, identify frequencies and bandwidths of one or more pseudo lights to be arranged in the frequency grid and corresponding to the frequencies and bandwidths indicated by the signal, and output the one or more pseudo lights whose frequencies and bandwidths have been identified; as well as a second multiplexing unit configured to multiplex the plurality of optical signals multiplexed by the first multiplexing unit and the one or more dummy lights output from the dummy light output unit to output a wavelength-multiplexed optical signal.

2. The optical transmission device according to claim 1, wherein: When an optical signal having a frequency different from that of the plurality of optical signals is additionally input to the first multiplexing unit, the dummy light output unit identifies dummy light corresponding to the frequency of the optical signal to be added from the one or more dummy lights and stops outputting the identified dummy light.

3. The optical transmission device according to claim 1 or 2, wherein: When there is an optical signal blocked from being input to the first multiplexing unit among the plurality of optical signals input to the first multiplexing unit, the dummy light output unit identifies dummy light corresponding to a frequency of the optical signal to be blocked and newly outputs the identified dummy light.

4. The optical transmission device according to claim 1 or 2, wherein: A plurality of frequency slots having predetermined widths are arranged in the frequency grid, and In each of the plurality of frequency slots, one optical signal or one dummy light is arranged, or one or more optical signals and one or more dummy lights are arranged without overlapping.

5. A terminal station device, comprising: one or more optical transceivers; as well as An optical transmission device in which a plurality of optical signals of different wavelengths are input from the one or more optical transceivers, wherein: The optical transmission device comprises: a first multiplexing unit, to which a plurality of optical signals of different frequencies arranged in a frequency grid are input, the first multiplexing unit being configured to multiplex the input optical signals; a pseudo-light output unit configured to receive a signal indicating frequencies and bandwidths constituting the frequency grid in which the plurality of optical signals are arranged, identify frequencies and bandwidths of one or more pseudo-lights to be arranged in the frequency grid and corresponding to the frequencies and bandwidths indicated by the signal, and output the one or more pseudo-lights whose frequencies and bandwidths have been identified; and a second multiplexing unit configured to multiplex the plurality of optical signals multiplexed by the first multiplexing unit and the one or more dummy lights output from the dummy light output unit to output a wavelength-multiplexed optical signal.

6. 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 in which a plurality of optical signals of different wavelengths are input from the one or more optical transceivers, wherein: The optical transmission device comprises: a first multiplexing unit, to which a plurality of optical signals of different frequencies arranged in a frequency grid are input, the first multiplexing unit being configured to multiplex the input optical signals; a pseudo-light output unit configured to receive a signal indicating frequencies and bandwidths constituting the frequency grid in which the plurality of optical signals are arranged, identify frequencies and bandwidths of one or more pseudo-lights to be arranged in the frequency grid and corresponding to the frequencies and bandwidths indicated by the signal, and output the one or more pseudo-lights whose frequencies and bandwidths have been identified; and a second multiplexing unit configured to multiplex the plurality of optical signals multiplexed by the first multiplexing unit and the one or more dummy lights output from the dummy light output unit to output a wavelength-multiplexed optical signal.

7. An optical communication method, comprising: multiplexing a plurality of optical signals of different frequencies arranged in a frequency grid; receiving a signal indicating frequencies and bandwidths constituting the frequency grid in which the plurality of optical signals are arranged, identifying frequencies and bandwidths of one or more pseudo lights to be arranged in the frequency grid and corresponding to the frequencies and bandwidths indicated by the signal, and outputting the one or more pseudo lights whose frequencies and bandwidths have been identified; and The multiplexed plurality of optical signals and the one or more dummy lights are multiplexed to output a wavelength multiplexed optical signal.

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