Optical transmission device, optical transmission system, and transmission method for optical transmission system

Abstract

An optical transmission system 300 comprises a ROADM device (200) that transmits and receives an optical signal via optical transmission paths (10, 20), and a communication device (400) that is connected to the ROADM device (200) via the optical transmission paths (10, 20). The ROADM device (200) comprises an SFP (250) for OSC that converts an electrical signal into an optical signal and vice versa and transmits and receives the optical signal via the optical transmission paths (10, 20). The communication device (400) comprises a response unit (420) that returns, to the ROADM device (200), the optical signal which was transmitted from the ROADM device (200).

Description

[Technical Field]

[0001] The present invention provides Optical transmission equipment, Optical transmission systems, and, Transmission method of optical transmission system By law Regarding. [Background technology]

[0002] In recent years, reconfigurable optical add-drop multiplexers (ROADMs) have been studied as a path management technology for efficiently operating optical communication networks. For example, ROADMs are configured as an optical mesh network consisting of ROADM nodes, with multiple ROADM devices connected in a mesh pattern via optical fibers.

[0003] Each ROADM device has an add / drop function that drops / adds any optical signal from a wavelength division multiplexing (WDM) signal from multiple routes, and a routing function that switches the route to any route.

[0004] Furthermore, ROADM devices generally have the function of transmitting and receiving supervisory control signals (hereinafter, this is also referred to as OSC (Optical Supervisory Channel)). In optical transmission systems, OSC uses OSC light to check the continuity of optical fibers, manage the optical power of signals, and manage wavelength information by passing signals through amplifier circuits and wavelength selective switches (WSS).

[0005] In the future, optical communication networks will require more flexible network configurations and fewer electrical termination points. In this case, ROADM devices may communicate optically with non-ROADM devices without electrical termination. In this case, the non-ROADM devices are considered to be devices without OSCs.

[0006] The main function of the OSC in a ROADM device is to manage the continuity of optical signals in the transmitter and receiver of each ROADM device, and to perform APSD (Auto Power Shut Down) to automatically cut off continuity if the optical signal is interrupted in the optical transmission path. The OSC's continuity management not only cuts off continuity, but also has the function of restoring it.

[0007] In addition, a typical ROADM device can manage optical power and wavelength information for each section by using an OSC, and therefore the ROADM device appropriately controls the amplifier circuit, VOA (Variable Optical Attenuator), and WSS (see, for example, Non-Patent Document 1). [Prior art documents] [Non-patent literature]

[0008] [Non-Patent Document 1] “Open ROADM MSA Device White Paper”, [online], [Retrieved February 4, 2022], Internet<http: / / openroadm.org / download.html> Summary of the Invention [Problem to be solved by the invention]

[0009] When communication between ROAD devices is performed based on the Open ROADM MSA (Multi-Source Agreement), OSC is essential for confirming communication or managing continuity in communication between ROADM devices.

[0010] In contrast, when communication is performed between a ROADM device and a communication device other than the ROADM device (a communication device that does not have an OSC), an optical connection is made without electrically terminating the network, which is detected as an error in the monitoring control unit and communication is not possible.

[0011] In this case, the simplest solution would be to remove the OSC from the ROADM device. However, the OSC light used in the OSC is also used for optical continuity checks. ROADM devices are generally used in core networks and communicate using high-power optical signals. Therefore, if the OSC is removed from the ROADM device, high-power optical signals will be used as signals for optical continuity, which could jeopardize the safety of workers. Furthermore, the OSC function cannot be removed because it is specified as a configuration in the Open ROADM MSA.

[0012] It is also possible to communicate with devices in other systems via the optical multiplexing / demultiplexing unit of the ROADM device, but in this case, there is a restriction that the two communicating devices (the ROADM device and the device in the other system) must be located in the same place.

[0013] The present invention has been made in consideration of these points, and aims to provide an optical transmission system, a transmission method for an optical transmission system, and a communication device that enable optical communication without electrically terminating a device in another system while maintaining the OSC function of the ROADM device. [Means for solving the problem]

[0014] The optical transmission system according to the present invention comprises: An optical transmission system comprising: an optical transmission device that transmits and receives optical signals via an optical transmission path; and a communication device connected to the optical transmission device by the optical transmission path, The optical transmission device includes: SFP (Small Form Factor Pluggable transceiver) converts electrical signals into optical signals and vice versa, and transmits and receives the optical signals via the optical transmission path. and, a monitoring control unit that monitors an optical signal, and when the optical signal returned from the communication device cannot be received, notifies the communication device via a network of a request for APSD (Auto Power Shut Down) to cut off continuity; Equipped with The communication device a response unit that returns an optical signal transmitted from the optical transmission device to the optical transmission device; picture, The monitoring control unit The SFP further includes a measurement unit that transmits an optical signal to the communication device and measures the optical power of a return signal that is returned by the response unit; If the optical power of the return signal measured by the measurement unit is lost, the communication device is notified of this via the network, and the return signal is amplified and transmitted. It is characterized by the following. [Effects of the Invention]

[0015] According to the present invention, it is possible to provide an optical transmission system, a transmission method for an optical transmission system, and a communication device that enable optical communication without electrically terminating a device in another system while maintaining the OSC function of the ROADM device. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 10 is an explanatory diagram showing a configuration when ROADM devices of the prior art communicate with each other, as a comparative example of this embodiment. [Figure 2] FIG. 10 is an explanatory diagram showing a configuration in which conventional ROADM devices communicate with each other in a loopback configuration using the OSC function, as a comparative example of this embodiment. [Figure 3] 1 is an explanatory diagram illustrating an optical transmission system according to a first embodiment, in which the optical transmission system is configured to include a communication device instead of a ROADM device. [Figure 4] FIG. 10 is an explanatory diagram showing a configuration when conventional ROADM devices check connectivity using the OSC function, as a comparative example of this embodiment. [Figure 5] FIG. 10 is an explanatory diagram showing a configuration in which conventional ROADM devices communicate with each other in a loopback configuration using the OSC function, as a comparative example of this embodiment. [Figure 6] FIG. 4 is an explanatory diagram showing a configuration in which the optical transmission system shown in FIG. 3 is connected via a network as a second embodiment. [Figure 7] FIG. 10 is an explanatory diagram showing a configuration in which conventional ROADM devices perform optical power management using an OSC function, as a comparative example of this embodiment. [Figure 8]FIG. 10 is an explanatory diagram showing a configuration in which conventional ROADM devices perform optical power management in a loopback configuration, as a comparative example of this embodiment. [Figure 9] 9 is an explanatory diagram in which the communication device shown in FIG. 6 is applied to the optical transmission system shown in FIG. 8 as a third embodiment. [Figure 10] FIG. 10 is an explanatory diagram showing a configuration in which a communication device in the optical transmission system shown in FIG. 9 includes an optical amplifier, as a fourth embodiment. [Figure 11] FIG. 10 is an explanatory diagram showing a configuration when wavelength information is managed by OCM between conventional ROADM devices, as a comparative example of this embodiment. [Figure 12] FIG. 10 is an explanatory diagram showing a configuration in which, as a comparative example of this embodiment, a monitoring control unit acquires wavelength information from a remote centralized monitoring device between conventional ROADM devices. [Figure 13] 13 is an explanatory diagram in which the communication device of FIG. 6 is applied to the optical transmission system of FIG. 12 as a fourth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Next, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described. First, an overview of the present technology will be described using a conventional technology as a comparative example. Note that the same components will be assigned the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0018] <Overview of this technology: Comparative Example 1> FIG. 1 is an explanatory diagram showing a configuration for communication between conventional ROADM (Reconfigurable Optical Add-Drop Multiplexer) devices as a comparative example of this embodiment.

[0019] 1, an optical transmission system 300 of Comparative Example 1 is configured to include a ROADM device 100 and a ROADM device 200. The ROADM device 100 and the ROADM device 200 are, for example, configured as the same optical transmission device, and are connected by optical transmission paths 10 and 20 configured of optical fibers.

[0020] The ROADM device 100 is configured to include a supervisory control unit 110, a transmission device 120, and an optical multiplexing / demultiplexing unit 190. The transmission device 120 is configured to include an OXC (Optical cross Connect) unit 130, an optical amplification unit 140, an OSC (Optical Supervisory Channel) SFP (Small Form Factor Pluggable transceiver) 150, a transmission unit 151, a reception unit 152, and an OCM (Optical Channel Monitor) 160.

[0021] The OXC unit 130 is configured to include a WSS (Wavelength Selective Switch) 131 and a WSS 132. The OXC unit 130 sets up optical communication paths for data transfer in the optical transmission paths 10 and 20. When data transmission paths of different formats exist for different purposes or transmission speeds, the OXC unit 130 outputs a predetermined data signal to a predetermined data transmission path. For example, the OXC unit 130 sets up a data transmission path as an optical communication path for each data center or internet service provider.

[0022] The WSSs 131 and 132 have, for example, an N-input, 1-output (N×1) or 1-input, N-output (1×N) Mux / Demux function, and output each WDM signal from an input port to an arbitrary output port.

[0023] The OXC unit 130 may be configured to include an arrayed-waveguide grating (AWG) (not shown) and a transponder (not shown). In this case, the OXC unit 130 outputs a predetermined optical signal from the transponder via the arrayed-waveguide grating as an output of the WSSs 131 and 132.

[0024] The optical amplification unit 140 includes a post-amplifier 141, a pre-amplifier 142, and a VOA (Variable Optical Attenuator) 143.

[0025] The postamplifier 141 is an optical amplifier that collectively amplifies the optical level of the WDM signal to be multiplexed and output to the optical transmission line 10. The preamplifier 142 is an optical amplifier that collectively amplifies the optical level of the WDM signal attenuated by the optical transmission line 20.

[0026] The VOA 143 is a variable optical attenuator with an optical attenuation function that adjusts the strength of the optical signal for each wavelength. The VOA 143 is located on the transmitting side and adjusts the strength of the optical input according to the characteristics of the optical path of the optical transmission line 10, such as the difference in amplification factor for each channel and the wavelength characteristics of the transmission path loss. In this way, the VOA 143 suppresses variations in the signal strength for each channel and keeps the optical output at a constant level on the receiving side.

[0027] The OCM 160 measures the wavelength spectrum of the optical signal input from the VOA 143 of the optical amplifying unit 140. The OCM 160 also measures the wavelength spectrum of the optical signal output from the preamplifier 142 of the optical amplifying unit 140.

[0028] The OSC SFP 150 converts electrical signals into optical signals and vice versa, and transmits and receives optical signals via optical transmission paths 10 and 20. The OSC SFP 150 transmits optical signals from a transmitting unit 151 constituting an output unit to the ROADM device 200, and receives optical signals transmitted from the ROADM device 200 at a receiving unit 152 constituting an input unit. The OSC SFP 150 has a transmitting terminal T and a receiving terminal R.

[0029] The monitoring and control unit 110 measures the optical power of the received OSC light at the transmitting unit 151, the receiving unit 152, the receiving terminal R of the OSC SFP 150, and the OCM 160 before and after the optical amplifying unit 140 (or before and after the WSSs 131 and 132). The monitoring and control unit 110 constantly monitors while measuring the optical power, and if a signal interruption is confirmed, performs APSD (Auto Power Shut Down) to automatically cut off continuity.

[0030] The OCM 160 may measure not only the wavelength spectrum but also the optical power and transmit the measurement results to the monitor and control unit 110.

[0031] Furthermore, information about the main signal system (such as wavelength used, number of wavelengths, noise information, and span loss) is superimposed on the optical signal (i.e., an OSC optical signal), and the ROADM device 100 and the ROADM device 200 communicate with each other to transmit and receive information. The supervisory control unit 110 issues instructions based on the transmission and reception of information, and performs amplifier control (amplification control) and WSS control (wavelength selection control) of the optical amplifier unit 140. This information about the main signal system is also called a supervisory control signal.

[0032] The optical multiplexing / demultiplexing unit 190 is configured to include an optical circuit (not shown) that demultiplexes input light into a plurality of beams and outputs the beams, and an optical circuit (not shown) that multiplexes a plurality of input light beams and outputs the multiplexed beams.

[0033] In this embodiment, the OSC SFP 150 is configured as an optical module, and the OSC SFP 150 and the monitoring control unit 110 configure the OSC function (corresponding to an OSC function unit). The OSC SFP 150 is an example of an SFP for performing optical communication. The OSC function configured by the OSC SFP 150 and the monitoring control unit 110 mainly performs three controls.

[0034] In the first control, the monitoring and control unit 110 checks the continuity of the optical signal at the transmitter 151, receiver 152, and receiving terminal R of the ROADM device 100, and executes APSD if the optical signal is blocked. In the second control, the transmission device 120 measures the optical power as optical power management. And in the third control, the OCM 160 measures the wavelength spectrum as wavelength information management.

[0035] Moreover, the optical transmission path 10 transmits an optical signal from the ROADM device 100 to the ROADM device 200. The optical transmission path 20 transmits an optical signal from the ROADM device 200 to the ROADM device 100. A supervisory control signal is superimposed on the optical signals communicated in the optical transmission paths 10 and 20.

[0036] In this embodiment, the monitoring and control unit 210 of the ROADM device 200 corresponds to the monitoring and control unit 110 of the ROADM device 100, and the transmission device 220 of the ROADM device 200 corresponds to the transmission device 120 of the ROADM device 100. The OXC unit 230 of the transmission device 220 corresponds to the OXC unit 130 of the transmission device 120, the optical amplification unit 240 of the transmission device 220 corresponds to the optical amplification unit 140 of the transmission device 120, and the OSC SFP 250 of the transmission device 220 corresponds to the OSC SFP 150 of the transmission device 120. The optical multiplexing and demultiplexing unit 290 of the ROADM device 200 corresponds to the optical multiplexing and demultiplexing unit 190 of the ROADM device 100.

[0037] Optical couplers 154 and 157 and optical couplers 254 and 257 are couplers that branch or combine optical signals, and are provided in the transmission devices 120 and 220 as appropriate.

[0038] 1 , in the ROADM device 100, the OSC SFP 150 transmits an optical signal from a transmission terminal T to the ROADM device 200 via a transmitter 151 and the optical transmission path 10. Meanwhile, in the ROADM device 200, the OSC SFP 250 receives the optical signal at a receiving terminal R via the optical transmission path 10 and a receiver 252.

[0039] In the ROADM device 200, the OSC SFP 250 transmits an optical signal from a transmission terminal T to the ROADM device 100 via a transmitter 251 and the optical transmission path 20. Meanwhile, in the ROADM device 100, the OSC SFP 150 receives the optical signal at a reception terminal R via the optical transmission path 20 and a receiver 152.

[0040] <Comparative Example 2> 2 is an explanatory diagram showing a configuration in which conventional ROADM devices communicate with each other in a loopback configuration using the OSC function, as a comparative example of this embodiment. Note that the optical multiplexing / demultiplexing unit 190 and the optical multiplexing / demultiplexing unit 290 shown in FIG. 1 are not shown in the figure because they are not related to the control of this embodiment.

[0041] As shown in Fig. 2, the optical transmission system 301 is configured to include a ROADM device 101 and a ROADM device 201. In the optical transmission system 301, similar to Fig. 1, the ROADM device 101 and the ROADM device 201 are configured as the same optical transmission device, and are connected by optical transmission paths 10 and 20 configured of optical fibers.

[0042] 1, the transmission device 121 of the ROADM device 101 is configured with optical couplers 155 and 156, an optical isolator 153, and optical filters 158, 159, and 170. The optical filters 158, 159, and 170 are optional components that are provided when OSC light is removed in order to increase wavelength utilization efficiency.

[0043] 1, the transmission device 221 of the ROADM device 201 is configured with optical couplers 255 and 256, an optical isolator 253, and optical filters 258, 259, and 270. The optical filters 258, 259, and 270 are optional components that are provided when OSC light is removed in order to increase wavelength utilization efficiency.

[0044] In the optical transmission system 301, the ROADM device 101 and the ROADM device 201 each have a loopback configuration. Specifically, in the ROADM device 101, the OSC SFP 150 transmits an optical signal from a transmission terminal T to the optical transmission path 10 via an optical coupler 154 and a transmission unit 151. The ROADM device 201 transmits an optical signal from the optical transmission path 10, which is input via a reception unit 252 and an optical coupler 256, to the optical transmission path 20 via an optical coupler 255 and a transmission unit 251. Then, the ROADM device 101 receives the loopback signal, which is input via the reception unit 152 and an optical coupler 157, at a reception terminal R of the OSC SFP 150.

[0045] Similarly, in the ROADM device 201, the OSC SFP 250 transmits an optical signal from the transmission terminal T to the optical transmission path 20 via the optical coupler 254 and the transmission unit 251. The ROADM device 101 transmits an optical signal input via the reception unit 152 and the optical coupler 156 to the optical transmission path 10 via the optical coupler 155 and the transmission unit 151. Then, the ROADM device 201 receives, at the reception terminal R, the loopback signal input via the reception unit 252 and the optical coupler 257 from the OSC SFP 250.

[0046] In the comparative example of the optical transmission system 301 shown in Figure 2, a return configuration is adopted in each of the ROADM device 101 and the ROADM device 201, so that optical signals are transmitted in duplicate in the optical transmission paths 10 and 20, as indicated by the thick solid arrows and dashed arrows.

[0047] First Embodiment 3 is an explanatory diagram showing an optical transmission system according to this embodiment, which is configured to include a communication device instead of a ROADM device. The optical transmission system 302 is configured to include a ROADM device 201 (optical transmission device) that transmits optical signals to optical transmission paths 10 and 20, and a communication device 400 connected to the ROADM device 201 via the optical transmission paths 10 and 20.

[0048] As shown in FIG. 3, a communication device 400 of an optical transmission system 302 includes a monitor control unit 410, a response unit 420, and a device 430 of another system.

[0049] The monitoring control unit 410 monitors the communication status of the communication device 400. The other-system device 430 includes, for example, a CPU (Central Processing Unit), a DSP (Digital Signal Processor) or an ASIC (Application Specific Integrated Circuit), is installed in the communication device 400, and performs predetermined signal processing. Note that the predetermined signal processing performed by the other-system device 430 is not particularly limited to communication control, image processing, audio processing, data control, etc.

[0050] The responding unit 420 is configured to return the optical signal transmitted from the ROADM device 201 to the ROADM device 201 .

[0051] The response unit 420 is configured to include optical couplers 422 and 423 , an optical isolator 421 , and a filter 424 .

[0052] The optical couplers 422 and 423 branch the optical signal transmitted from the ROADM device 201. The optical isolator 421 outputs an optical signal from a device 430 of another system in one direction to the optical coupler 422. Due to the presence of this optical isolator 421, the optical signals branched by the optical couplers 422 and 423 are transmitted in the direction of the ROADM device 201. In other words, the optical isolator 421 plays a role in blocking the optical signal branched by the optical coupler 422 from traveling in the direction of the device 430 of another system and transmitting it in the direction of the ROADM device 201. The filter 424 is an optional component that is provided when removing OSC light in order to increase wavelength utilization efficiency.

[0053] In the optical transmission system 302 according to this embodiment, the OSC SFP 250 of the transmission device 221 transmits an optical signal from the transmission terminal T to the optical transmission path 20 via the optical coupler 254 and the transmission unit 251. The response unit 420 of the communication device 400 returns the optical signal input via the optical coupler 423 and the filter 424 to the optical transmission path 10 via the optical coupler 422. In the ROADM device 201, the OSC SFP 250 receives, at the reception terminal R, the return signal input from the optical transmission path 10 via the reception unit 252 and the optical coupler 257.

[0054] As a result, the optical transmission system 302 of this embodiment can perform optical communication between the ROADM device 201 and the communication device 400 while maintaining the OSC function of the ROADM device 201 and without electrically terminating the device 430 of another system.

[0055] The ROADM device 201 also includes a monitoring control unit 210. The monitoring control unit 210 monitors the optical signals received by the transmitting unit 251, the receiving unit 252, and the receiving terminal R of the SFP 250 for OSC.

[0056] As a result, the monitoring control unit 210 issues an APSD request to cut off continuity when, for example, the optical signal (return signal) returned from the responding unit 420 of the communication device 400 cannot be received at the receiving terminal R of the OSC SFP 250. In this case, the monitoring control unit 210 may cut off the continuity of the ROADM device 201 or may cut off the continuity of the transmission device 221.

[0057] <Comparative Example 3> 4 is an explanatory diagram showing a configuration when conventional ROADM devices check communication between each other using the OSC function, as a comparative example of this embodiment. Note that the monitoring control signals controlled by the monitoring control units 110 and 210 will be described using the explanatory diagram shown in FIG.

[0058] As shown in FIG. 4, in an optical transmission system 300 as a comparative example, a monitor and control unit 110 monitors an OSC SFP 150, and a monitor and control unit 210 monitors an OSC SFP 250.

[0059] 1, in the ROADM device 100, the OSC SFP 150 transmits an optical signal from the transmission terminal T to the ROADM device 200 via the transmission unit 151 and the optical transmission path 10. In this case, the monitoring and control unit 210 monitors whether the optical signal has been received by the transmission unit 251, the reception unit 252, and the reception terminal R of the OSC SFP 250.

[0060] For example, when an optical fiber is cut in the optical transmission path 10 and the monitoring control unit 210 detects that the OSC SFP 250 cannot receive an optical signal at the receiving terminal R, the OSC SFP 250 notifies the receiving terminal R of the OSC SFP 150 of an APSD request from the transmitting terminal T via the transmitting unit 251 and the optical transmission path 20. Specifically, the monitoring control unit 210 superimposes a signal indicating an APSD request, which is a monitoring control signal, on the optical signal and transmits it to the monitoring control unit 110.

[0061] The monitoring control unit 110 monitors the receiving terminal R of the OSC SFP 150, and accepts the APSD request when the OSC SFP 150 receives a signal indicating a superimposed APSD request at the receiving terminal R. In response to receiving this APSD request, the monitoring control unit 110 cuts off the continuity of the ROADM device 100 or the transmission device 120.

[0062] <Comparative Example 4> 5 is an explanatory diagram showing a configuration in which conventional ROADM devices communicate with each other in a loopback configuration using the OSC function, as a comparative example of this embodiment. Note that the optical signals monitored by the monitoring and control units 110 and 210 will be explained using the explanatory diagram shown in FIG.

[0063] As shown in FIG. 5, in an optical transmission system 301 serving as a comparative example, the monitor and control unit 110 monitors the OSC SFP 150, and the monitor and control unit 210 monitors the OSC SFP 250.

[0064] 5, as described in FIG. 2, in the ROADM device 101, the OSC SFP 150 transmits an optical signal from the transmission terminal T to the optical transmission path 10 via the optical coupler 154 and the transmitter 151, as indicated by the thick solid arrow. The ROADM device 201 transmits an optical signal input via the receiver 252 and the optical coupler 256 to the optical transmission path 20 via the optical coupler 255 and the transmitter 251, as indicated by the thick solid arrow. Then, the ROADM device 101 receives a return signal input via the OSC SFP 150 at the reception terminal R via the receiver 152 and the optical coupler 157, as indicated by the thick solid arrow.

[0065] Similarly, in the ROADM device 201, the OSC SFP 250 transmits an optical signal from the transmission terminal T to the optical transmission path 20 via the optical coupler 254 and the transmitter 251, as indicated by the dashed arrow. The ROADM device 101 transmits an optical signal input via the receiver 152 and the optical coupler 156 to the optical transmission path 10 via the optical coupler 155 and the transmitter 151, as indicated by the dashed arrow. Then, the ROADM device 201 receives, at the reception terminal R, the return signal input via the receiver 252 and the optical coupler 257, as indicated by the dashed arrow.

[0066] However, in this comparative example, optical signals cannot be transmitted or received because both optical signals (OSC signals) indicated by the thick solid arrows and dashed arrows of the OSC SFP150 and the OSC SFP250 pass in the same direction through the optical transmission paths 10, 20. That is, even if the OSC SFP150 transmits an optical signal, it cannot receive a return signal, and even if the OSC SFP250 transmits an optical signal, it cannot receive a return signal.

[0067] Therefore, the monitoring and control unit 110 detects an APSD request due to the occurrence of an error in the optical transmission paths 10 and 20 at the receiving terminal R of the OSC SFP 150. Similarly, the monitoring and control unit 210 detects an APSD request due to the occurrence of an error in the optical transmission paths 10 and 20 at the receiving terminal R of the OSC SFP 250. As a result, in the optical transmission system 301, the monitoring and control unit 110 and the monitoring and control unit 210 each cut off the continuity of the ROADM device 101 and the ROADM device 201, or cut off the continuity of the transmission device 121 and the transmission device 221.

[0068] <Second embodiment> Fig. 6 is an explanatory diagram showing a configuration in which the optical transmission system shown in Fig. 3 is connected via a network as a second embodiment. The explanatory diagram shown in Fig. 6 differs from the explanatory diagram in Fig. 3 in that the optical transmission system is connected via a network.

[0069] As shown in FIG. 6, in an optical transmission system 303 according to this embodiment, the monitor and control unit 410 and the monitor and control unit 210 of the optical transmission system 302 shown in FIG.

[0070] For example, when the OSC SFP 250 cannot receive the return signal returned from the responding unit 420 of the communication device 400 at the receiving terminal R, the monitoring control unit 210 according to this embodiment notifies an external monitoring control unit, for example, a remote centralized monitoring device (not shown), via the network 500. In this case, the remote centralized monitoring device notifies the monitoring control unit 410 of the communication device 400 of a request for APSD.

[0071] This allows the monitoring control unit 410 to receive an instruction from the remote centralized monitoring device and cut off the continuity of the communication device 400. The remote centralized monitoring device may also notify the ROADM device 201 and / or the transmission device 221 of an APSD request via the network 500, and cut off the continuity of the ROADM device 201 and / or the transmission device 221.

[0072] <Comparative Example 5> 7 is an explanatory diagram showing a configuration in which conventional ROADM devices perform optical power management using the OSC function, as a comparative example of this embodiment. Note that this comparative example will be described using an example in which the monitoring control unit 210 measures the optical power of the receiving unit 252, with reference to the explanatory diagram shown in FIG.

[0073] As shown in Figure 7, the optical transmission system 304 as a comparative example corresponds to the configuration of the optical transmission system 300 (Figure 1), and differs in that the monitoring control unit 211 of the ROADM device 202 is equipped with a measurement unit 212.

[0074] As indicated by the thick solid arrow, when the ROADM device 202 receives an optical signal transmitted from the transmitting terminal T of the OSC SFP 150 of the ROADM device 101, the measuring unit 212 measures the optical power of the received optical signal. Note that the measuring unit 212 constantly measures and observes the optical power at the transmitting unit 251, the receiving unit 252, and the receiving terminal R of the OSC SFP 250.

[0075] Specifically, the ROADM device 101 transmits an optical signal from the transmission terminal T of the OSC SFP 150 to the ROADM device 202. Assume that the measurement unit 212 of the monitoring and control unit 211 of the ROADM device 202 detects, for example, a decrease in the received optical power at the receiving unit 252. In this case, the monitoring and control unit 211 superimposes a monitoring and control signal that increases the optical power onto the optical signal, and the OSC SFP 250 transmits the signal from the transmission terminal T to the ROADM device 101, as indicated by the dashed arrow.

[0076] In the comparative example shown in Figure 7, the monitoring control unit 211 superimposes a monitoring control signal that increases the optical power onto the optical signal and transmits it from the transmitting terminal T of the OSC SFP 250 to the receiving terminal R of the OSC SFP 150 of the ROADM device 101, as shown by the dashed arrow.

[0077] When the OSC SFP 150 receives a monitoring control signal at the receiving terminal R to increase the optical power of the receiving unit 252, the monitoring control unit 111 of the ROADM device 101 controls the post-amplifier 141 and VOA 143 to increase the transmission power (optical power) of the optical signal to be transmitted.

[0078] In addition, the monitoring control unit 211 may measure the loss of the transmission path between the ROADM device 101 and the ROADM device 202 (span loss measurement) and send a monitoring control signal to the monitoring control unit 111 to adjust the levels of the postamplifier 141 and the VOA 143 according to the span loss.

[0079] <Comparative Example 6> 8 is an explanatory diagram showing a configuration in which conventional ROADM devices perform optical power management in a loopback configuration as a comparative example of this embodiment. The monitoring and control unit 211 and the monitoring and control unit 111 of the optical transmission system 305 shown in FIG. 8 are connected via a network 500.

[0080] As shown in Figure 8, in the optical transmission system 305 as a comparative example, compared to the optical transmission system 304 (Figure 7), the monitoring control unit 211 of the ROADM device 203 is connected to an external monitoring control unit, for example, a remote centralized monitoring device (not shown), via a network 500.

[0081] 8, the ROADM device 101 and the ROADM device 203 cannot transmit and receive optical signals between the OSC SFP 150 and the OSC SFP 250, as described in Fig. 5. Therefore, the remote centralized monitoring device controls the monitoring control unit 111 of the ROADM device 101 to increase the optical power of the receiving unit 252 of the ROADM device 203 by controlling the post-amplifier 141 and the VOA 143, thereby increasing the transmission power to be transmitted.

[0082] In addition, the monitoring and control unit 211 may measure the loss of the transmission path between the ROADM device 101 and the ROADM device 203 (span loss measurement), and have the monitoring and control unit 111 adjust the levels of the post-amplifier 141 and the VOA 143 according to the span loss using a remote centralized monitoring device.

[0083] <Third embodiment> Fig. 9 is an explanatory diagram of a third embodiment in which the communication device shown in Fig. 6 is applied to the optical transmission system shown in Fig. 8. The explanatory diagram shown in Fig. 9 differs from the explanatory diagram of Fig. 8 in that a communication device 401 is provided instead of the ROADM device 101.

[0084] As shown in FIG. 9, an optical transmission system 306 according to this embodiment is provided with a communication device 401 instead of the ROADM device 101 in the optical transmission system 305 shown in FIG.

[0085] The monitoring and control unit 211 of the ROADM device 203 includes a measuring unit 212 that measures the optical power of the return signal returned by the responding unit 420. If the optical power of the return signal measured by the measuring unit 212 is lost, the monitoring and control unit 211 notifies the remote centralized monitoring device via the network 500, and causes the monitoring and control unit 411 to amplify the transmission power of the return signal and transmit it.

[0086] As a result, in the communication device 401, the monitoring and control unit 411 receives an instruction from the remote centralized monitoring device and controls the amplifier to increase the transmission power, thereby increasing the optical power of the return signal from the responding unit 420. Note that the monitoring and control unit 411 only needs to be able to increase the transmission power of the responding unit 420, and the method of amplifier control is not limited thereto.

[0087] <Fourth embodiment> Fig. 10 is an explanatory diagram showing a configuration in which a communication device in the optical transmission system shown in Fig. 9 includes an optical amplifier unit as a fourth embodiment. The diagram shown in Fig. 10 differs from the diagram in Fig. 9 in that a communication device 402 further includes an optical amplifier unit 440.

[0088] As shown in FIG. 10, an optical transmission system 307 according to this embodiment is configured such that an optical amplifier 440 is provided in the communication device 401 of the optical transmission system 306 shown in FIG.

[0089] The optical amplifier 440 has a function of amplifying the transmission power for transmitting a return signal, and is configured to include a post-amplifier 441, a pre-amplifier 442, a VOA 443, and an OCM 460.

[0090] The postamplifier 441 is equivalent to the postamplifier 141 , the preamplifier 442 is equivalent to the preamplifier 142 , the VOA 443 is equivalent to the VOA 143 , and the OCM 460 is equivalent to the OCM 160 .

[0091] The optical amplifier 440 receives an instruction from the monitor and control unit 411, amplifies the transmission power of the optical signal received by the responder 420 via the optical transmission line 20, and transmits the signal as a return signal via the optical transmission line 10.

[0092] In this way, the communication device 402 can increase the transmission power for transmitting the return signal when the monitor and control unit 411 receives an instruction from the remote centralized monitor.

[0093] <Comparative Example 7> FIG. 11 is an explanatory diagram showing a configuration in which wavelength information is managed by OCM between conventional ROADM devices, as a comparative example of this embodiment.

[0094] As shown in Figure 11, in an optical transmission system 308 as a comparative example, the monitoring control unit 213 of the ROADM device 203 acquires the wavelengths in use and the number of wavelengths as wavelength information of the node (ROADM device 100) from the optical signal received at the receiving terminal R of the OSC SFP 250.

[0095] For example, the monitoring and control unit 213 controls the post-amplifier 241 of the optical amplifying unit 240 and the WSS 231 of the OXC unit 230 based on wavelength information of the node (ROADM device 100) received at the receiving terminal R of the OSC SFP 250. Specifically, the monitoring and control unit 213 opens a wavelength port and / or adjusts the amplifier based on the acquired wavelength information.

[0096] Furthermore, the OCM 260 measures the wavelength spectrum of the optical signal received from the ROADM device 100, and notifies the monitoring and control unit 213 of wavelength information such as the wavelengths used and the number of wavelengths. As a result, the monitoring and control unit 213 controls the OXC unit 230 based on the wavelength information measured by the OCM 260, and controls the wavelength port to be used.

[0097] For example, if the wavelength that should be acquired cannot be measured by the OCM 260, the monitoring and control unit 213 closes the wavelength port of the wavelength that cannot be measured in the WSS 231. Furthermore, the monitoring and control unit 213 measures the wavelengths in use, and if the wavelength tilt is large, corrects the variation in optical power for each wavelength and performs control to align the wavelength tilt.

[0098] <Comparative Example 8> 12 is an explanatory diagram showing a configuration in which a monitoring control unit acquires wavelength information from a remote centralized monitoring device between conventional ROADM devices as a comparative example to this embodiment. In FIG. 12, the monitoring control unit 214 includes an acquisition unit 215 that acquires the wavelength and number of wavelengths used by the node (ROADM device 100) as wavelength information from the remote centralized monitoring device via the network 500.

[0099] In this case, the monitoring and control unit 214 acquires wavelength information on the wavelengths and number of wavelengths used by the node from the remote centralized monitoring device, and also acquires wavelength information on the measured wavelengths and number of wavelengths used from the OCM 260 .

[0100] In the case of FIG. 12, the monitor and control unit 214 compares the wavelength information acquired from the remote centralized monitor device by the acquisition unit 215 with the wavelength information measured by the OCM 260 .

[0101] 11, if the wavelength to be acquired cannot be measured by the OCM 260, the monitoring and control unit 214 closes the wavelength port of the wavelength that cannot be acquired in the WSS 231. In addition, the monitoring and control unit 214 measures the wavelength to be used by the OCM 260, and if the wavelength tilt is large, corrects the variation in optical power for each wavelength and performs control to align the wavelength tilt.

[0102] <Fourth embodiment> Fig. 13 is an explanatory diagram showing, as a fourth embodiment, the application of the communication device of Fig. 6 to the optical transmission system shown in Fig. 12. That is, the optical transmission system 310 shown in Fig. 13 is a combination of a communication device 403 corresponding to the communication device 400 shown in Fig. 6 and the ROADM device 204 of the optical transmission system 309 shown in Fig. 12.

[0103] 13, the communication device 403 is connected to the ROADM device 204 via a network 500. In this case, the monitoring control unit 412 transmits wavelength information that is returned by the response unit 420 of the communication device 403 as a node (communication device 403) to the monitoring control unit 214 via a remote centralized monitoring device. The monitoring control unit 214 has an acquisition unit 215, and therefore acquires the wavelength and number of wavelengths used by the node (communication device 403) as wavelength information.

[0104] The ROADM device 204 includes an OCM 260 (optical monitor) that measures the wavelength spectrum of the return signal returned by the responder 420 of the communication device 403, and an OXC unit 230 (optical cross-connect unit) that selects and sets an optical transmission path. The OXC unit 230 includes WSSs 231 and 232 that select wavelengths in the wavelength spectrum.

[0105] The monitor and control unit 214 includes an acquisition unit 215 , which acquires wavelength information relating to the wavelength spectrum transmitted from the communication device 403 .

[0106] If the measurement result of the wavelength spectrum measured by the OCM 260 does not match the wavelength information acquired by the acquisition unit 215, the monitoring control unit 214 controls the WSSs 231 and 232 in accordance with the measurement result and / or controls the power for each wavelength of the measured wavelength spectrum.

[0107] In this way, the monitoring and control unit 214 compares the wavelength information acquired by the acquisition unit 215 with the wavelength information measured by the OCM 260. Furthermore, if the wavelength information acquired by the acquisition unit 215 and the wavelength information measured by the OCM 260 differ and a wavelength that should have been acquired cannot be measured, the monitoring and control unit 214 closes the wavelength port of the wavelength that cannot be measured in the WSS 231. Furthermore, if there is variation in the optical power of the measured wavelengths and the wavelength tilt is large, the monitoring and control unit 211 corrects the optical power for each wavelength and controls to align the wavelength tilt.

[0108] <Effects> The effects of the optical transmission system 302 according to the present invention and the communication device 400 connected to the ROADM device 200 will be described below.

[0109] The optical transmission system 302 of the present invention is an optical transmission system comprising a ROADM device 201 that transmits and receives optical signals via optical transmission paths 10 and 20, and a communication device 400 connected to the ROADM device 201 via the optical transmission paths 10 and 20, wherein the ROADM device 201 is provided with an OSC SFP250 that converts electrical signals into optical signals and vice versa, and transmits and receives the optical signals via the optical transmission paths 10 and 20, and the communication device 400 is provided with a response unit 420 that returns the optical signal transmitted from the ROADM device 201 to the ROADM device 201.

[0110] As a result, in the optical transmission system 302 according to this embodiment, an optical signal is transmitted from the OSC SFP 250 to the optical transmission path 20. The responding unit 420 of the communication device 400 returns the transmitted optical signal to the ROADM device 201 via the optical transmission path 10. Then, the ROADM device 201 receives the returned signal transmitted from the OSC SFP 250.

[0111] Therefore, the optical transmission system 302 according to this embodiment allows the ROADM device 201 and the communication device 400 to perform optical communication while maintaining the OSC function of the ROADM device 201 and without electrically terminating the device 430 of another system.

[0112] Furthermore, the optical transmission system 303 according to the present invention further includes a monitoring control unit 210 that monitors the optical signal, and if the monitoring control unit 210 is unable to receive the return signal from the communication device 400, it notifies the communication device 400 via the network of a request for APSD (Auto Power Shut Down) to cut off continuity.

[0113] As a result, in the optical transmission system 302, the monitor and control unit 410 can cut off the continuity of the communication device 400.

[0114] Furthermore, in the optical transmission system 306 according to the present invention, the monitoring and control unit 211 further includes a measurement unit 212 that measures the optical power of a return signal that is generated when the OSC SFP 250 transmits an optical signal to the communication device 401 and the response unit 420 returns the optical signal, and if there is a loss in the optical power of the return signal measured by the measurement unit 212, the monitoring and control unit 211 notifies the communication device 401 via the network, causing the communication device 401 to amplify and transmit the transmission power of the return signal.

[0115] As a result, the communication device 401 can increase the transmission power of the return signal from the responding unit 420 by controlling the monitor control unit 411 to increase the transmission power.

[0116] In the optical transmission system 307 according to the present invention, the communication device 402 is characterized by further comprising an optical amplifier 440 for amplifying the transmission power for transmitting the return signal.

[0117] As a result, the communication device 402 can increase the transmission power of the return signal by the optical amplifier 440 in the monitor and control unit 411 .

[0118] Furthermore, in the optical transmission system 310 according to the present invention, the ROADM device 204 further comprises an OCM 260 that measures the wavelength spectrum of the return signal returned by the response unit 420, and an OXC unit 230 that selects and sets up an optical transmission path, the OXC unit 230 has WSSs 231 and 232 that select wavelengths in the wavelength spectrum, the monitoring and control unit 214 further comprises an acquisition unit 215 that acquires wavelength information regarding the wavelength spectrum to be transmitted, and when the measurement result of the wavelength spectrum measured by the OCM 260 does not match the wavelength information acquired by the acquisition unit 215, the monitoring and control unit 214 controls the WSSs 231 and 232 in accordance with the measurement result and / or controls the power for each wavelength of the measured wavelength spectrum.

[0119] This allows the monitoring and control unit 214 to compare the wavelength information acquired by the acquisition unit 215 with the wavelength information measured by the OCM 260. If the wavelength information acquired by the acquisition unit 215 and the wavelength information measured by the OCM 260 differ and the wavelength that should have been acquired cannot be measured, the monitoring and control unit 214 closes the wavelength port of the wavelength that cannot be measured in the WSS 231. Furthermore, if there is variation in the optical power of the measured wavelengths and the wavelength tilt is large, the monitoring and control unit 211 can correct the optical power for each wavelength and correct the wavelength tilt.

[0120] Furthermore, in the optical transmission system 302 according to the present invention, the responding unit 420 includes optical couplers 422 and 423 that branch an optical signal transmitted from the ROADM device 201, and an optical isolator 421 connected between the optical couplers 422 and 423 and a device 430 of another system that transmits the optical signal. The optical isolator 421 is characterized in that it blocks the optical signal branched by the optical couplers 422 and 423 from reaching the device 430 of the other system, and transmits the optical signal in the direction of the ROADM device 201.

[0121] As a result, the response unit 420 can return the optical signal input via the optical coupler 423 to the optical transmission line 10 using the optical isolator 421 and the optical coupler 422 without electrically terminating the device 430 of the other system.

[0122] The present invention is not limited to the above-described embodiments, and many modifications can be made by a person skilled in the art within the technical concept of the present invention. [Explanation of symbols]

[0123] 100,200~204 ROADM equipment (optical transmission equipment) 110,210,211,213,214 Monitoring control unit 120,121,220,221 Transmission equipment 130,230 OXC section (optical cross connect section) 131,132,231,232 WSS (wavelength selective switch) 140,240 Optical amplifier 141,241 Post-amplifier 142,242 Preamp 143,243 VOA 150,250 SFP for OSC 151,251 Transmitter 152,252 receiving unit 153,253,421 Optical isolator 154,157,254,257 Optical Coupler 158,159,170,258,259,270 Optical filters 160,260 OCM (Optical Monitor) 212 Measuring section 215 Acquisition Department 300~310 Optical transmission system 400~403 Communication equipment 420 Response Section 440 Optical Amplifier 500 Network

Claims

1. An optical transmission system comprising: an optical transmission device that transmits and receives optical signals via an optical transmission path; and a communication device connected to the optical transmission device by the optical transmission path, The optical transmission device includes: a small form factor pluggable transceiver (SFP) that converts electrical signals into optical signals and vice versa, and transmits and receives the optical signals via the optical transmission path; a monitoring control unit that monitors an optical signal, and when the optical signal returned from the communication device cannot be received, notifies the communication device via a network of a request for APSD (Auto Power Shut Down) to cut off electrical continuity; The communication device a response unit that returns an optical signal transmitted from the optical transmission device to the optical transmission device; The monitoring control unit The SFP transmits an optical signal to the communication device, and the responder measures the optical power of a return signal obtained by returning the optical signal, If the optical power of the return signal measured by the measurement unit is lost, the communication device is notified of this via the network, and the return signal is amplified and transmitted. An optical transmission system comprising:

2. The communication device further comprising an optical amplifier that amplifies the transmission power of the return signal; 2. The optical transmission system according to claim 1.

3. An optical transmission system comprising: an optical transmission device that transmits and receives optical signals via an optical transmission path; and a communication device connected to the optical transmission device by the optical transmission path, The optical transmission device includes: a small form factor pluggable transceiver (SFP) that converts electrical signals into optical signals and vice versa, and transmits and receives the optical signals via the optical transmission path; a monitoring control unit that monitors an optical signal, and when the optical signal returned from the communication device cannot be received, notifies the communication device via a network of a request for APSD (Auto Power Shut Down) to cut off electrical continuity; The communication device a response unit that returns an optical signal transmitted from the optical transmission device to the optical transmission device; The optical transmission device includes: an optical monitor for measuring the wavelength spectrum of the return signal returned by the response unit; an optical cross-connect unit that selects and sets an optical transmission path; The optical cross-connect unit a wavelength selective switch for selecting wavelengths in the wavelength spectrum; The monitoring control unit an acquisition unit that acquires wavelength information regarding the wavelength spectrum to be transmitted; When the measurement result of the wavelength spectrum measured by the optical monitor does not match the wavelength information acquired by the acquisition unit, the wavelength selection switch is controlled in accordance with the measurement result, and / or the power of each wavelength of the measured wavelength spectrum is controlled. An optical transmission system comprising:

4. The response unit an optical coupler that branches an optical signal transmitted from the optical transmission device; an optical isolator connected between the optical coupler and a device of another system that transmits an optical signal; The optical isolator comprises: the optical signal branched by the optical coupler is blocked from reaching the device of the other system and is transmitted in the direction of the optical transmission device; 4. The optical transmission system according to claim 1, wherein:

5. A transmission method for an optical transmission system including an optical transmission device that transmits an optical signal to an optical transmission line, and a communication device connected to the optical transmission device by the optical transmission line, comprising: the optical transmission device converting the electrical signal into an optical signal and transmitting the optical signal to the communication device via the optical transmission path; a step of the communication device returning the optical signal transmitted from the optical transmission device to the optical transmission device; receiving, by the optical transmission device, a return signal returned from the communication device; the optical transmission device monitors an optical signal, and if the return signal cannot be received, notifies the communication device via a network of a request for APSD (Auto Power Shut Down) to cut off continuity; the optical transmission device measures the optical power of the return signal, and if the optical power of the return signal is lost, notifies the communication device via the network, thereby amplifying the transmission power of the return signal and transmitting it; A transmission method for an optical transmission system, comprising:

6. A transmission method for an optical transmission system including an optical transmission device that transmits an optical signal to an optical transmission line, and a communication device connected to the optical transmission device by the optical transmission line, comprising: the optical transmission device converting the electrical signal into an optical signal and transmitting the optical signal to the communication device via the optical transmission path; a step of the communication device returning the optical signal transmitted from the optical transmission device to the optical transmission device; receiving, by the optical transmission device, a return signal returned from the communication device; the optical transmission device monitors an optical signal, and if the return signal cannot be received, notifies the communication device via a network of a request for APSD (Auto Power Shut Down) to cut off continuity; When the measurement result of the wavelength spectrum of the return signal measured by an optical monitor does not match the acquired wavelength information regarding the wavelength spectrum to be transmitted, the optical transmission device controls a wavelength selection switch that selects a wavelength in the wavelength spectrum in accordance with the measurement result, and / or controls the power of each wavelength in the measured wavelength spectrum; A transmission method for an optical transmission system, comprising:

7. An optical transmission device that transmits and receives optical signals via an optical transmission line, The optical transmission device includes: a small form factor pluggable transceiver (SFP) that converts electrical signals into optical signals and vice versa, and transmits and receives the optical signals via the optical transmission path; a monitoring control unit that monitors an optical signal, and when the optical signal returned from a communication device connected by the optical transmission line cannot be received, notifies the communication device via a network of a request for APSD (Auto Power Shut Down) to cut off continuity; The monitoring control unit The SFP further includes a measurement unit that transmits an optical signal to the communication device and measures the optical power of a return signal obtained by returning the optical signal, If the optical power of the return signal measured by the measurement unit is lost, the communication device is notified of this via the network, and the return signal is amplified and transmitted. An optical transmission device characterized by:

8. An optical transmission device that transmits and receives optical signals via an optical transmission line, The optical transmission device includes: a small form factor pluggable transceiver (SFP) that converts electrical signals into optical signals and vice versa, and transmits and receives the optical signals via the optical transmission path; a monitoring control unit that monitors an optical signal, and when a return signal that is the optical signal returned from a communication device connected by the optical transmission line cannot be received, notifies the communication device via a network of a request for APSD (Auto Power Shut Down) to cut off continuity; The optical transmission device includes: an optical monitor for measuring the wavelength spectrum of the folded signal; an optical cross-connect unit that selects and sets an optical transmission path; The optical cross-connect unit a wavelength selective switch for selecting wavelengths in the wavelength spectrum; The monitoring control unit an acquisition unit that acquires wavelength information regarding the wavelength spectrum to be transmitted; When the measurement result of the wavelength spectrum measured by the optical monitor does not match the wavelength information acquired by the acquisition unit, the wavelength selection switch is controlled in accordance with the measurement result, and / or the power of each wavelength of the measured wavelength spectrum is controlled. An optical transmission device characterized by:

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