Optical transmission device and optical transmission method

Abstract

An optical transmission device (100) comprises: an input light intensity monitor (120) that adjusts the light intensity of a transmission wavelength signal input to an optical relay node; a wavelength conversion unit (130) that converts the wavelength of a transmission wavelength signal obtained as a result of an input light intensity adjustment unit adjusting the light intensity; a WSS (140) that divides a transmission wavelength signal to be relayed into a transmission wavelength signal having the same wavelength as that prior to the wavelength conversion and a monitoring wavelength signal other than the transmission wavelength signal; an output light intensity monitor (160) that adjusts the light intensity of the transmission wavelength signal separated by the WSS (140); a monitor measurement instrument (150) that measures the transmission quality of the monitoring wavelength signal separated by the WSS (140); and a control unit (110) that controls the input light intensity monitor (120), the WSS (140), and the output light intensity monitor (160).

Description

Optical transmission device and optical transmission method The present invention relates to an optical transmission device and an optical transmission method. In an optical transmission system that connects a sending node and a receiving node with a relatively long-distance optical fiber cable and transmits an optical signal, it is expected that the optical signal will be significantly attenuated along the transmission path, and the transmission quality will deteriorate. Therefore, in order to ensure that the optical signal transmitted from the sending node reaches the receiving node, it is generally necessary to place one or more relay nodes along the transmission path to amplify the attenuated optical signal and to correct bit errors that occur along the transmission path. Furthermore, since relay nodes must usually be placed at regular intervals, when performing long-distance optical transmission, a large number of relay nodes are connected to intermediate portions of the transmission path between the transmitting node and the receiving node. Each relay node in an optical transmission system usually has an electrical termination function. That is, it converts the received optical signal into an electrical signal and relays the converted electrical signal information. When processing the electrical signal information, it can also obtain transmission quality data (pre-FEC BER, dispersion compensation amount, polarization mode dispersion amount, polarization dependent loss) at the relay node. However, if electrical termination is performed at each relay node, the increase in delay time due to the relay processing of electrical signals is unavoidable. In addition, the relay processing of electrical signals increases power consumption. In addition, there are limitations on the wavelength resources available for optical transmission, which hinders the expansion of transmission capacity. On the other hand, in recent years, the functionality of optical fiber cables and optical transmitters has improved. Therefore, there is a trend to expand the intervals between relay nodes equipped with electrical termination processing. This reduces the number of relay nodes while performing electrical termination processing, making it possible to reduce power consumption, increase capacity, and reduce latency in the network. On the other hand, for example, Non-Patent Document 1 discloses a technology for an optical transport network that omits electrical termination processing in optical node devices. Non-Patent Document 1 also discloses the introduction of a wavelength conversion function that converts the wavelength of an optical signal to another wavelength in the optical node devices that are passed through in order to efficiently use limited wavelength resources. When a fault occurs in an optical transmission system, it is necessary to identify the location of the fault. To do this, it is first necessary to divide the entire length of a long-distance transmission line into multiple sections at each relay node, and then to determine whether or not a fault has occurred in each section. If each relay node is equipped with an electrical termination function, it is possible to obtain transmission quality data for each relay node. By comparing the transmission quality data of each relay node, it becomes possible to determine whether a fault has occurred in each section. However, for relay nodes that do not implement electrical termination processing, it is not possible to obtain transmission quality data at those points. As a result, each section where it is possible to isolate whether or not there is a fault may contain many optical transmission devices, and the length of the optical fiber cable per section may become very long, making it difficult to identify the location of the fault. Therefore, for example, it is conceivable to place an optical splitter at a relay node. That is, one optical signal received by a relay node is split into two paths by the optical splitter, and the main signal of one path is relayed as an optical signal, while the optical signal of the other path is converted to an electrical signal and used to acquire transmission quality data. This reduces the signal delay of the optical main signal caused by relaying. However, since the optical intensity of the relayed optical main signal decreases when the input optical signal passes through the optical splitter, degradation of the transmission quality occurs at the relay node. <Configuration of Optical Transmission System> FIG. 7 is a diagram showing an example of the configuration of a typical optical transmission system 1A. 7, the optical transmission system 1A includes seven optical transmission devices 10-1, 10-2, 10-3, 10-4, 10-5, 10-6, and 10-7, which are connected in series to each other via a common optical fiber cable 15. A network controller 20 is connected to each of the optical transmission devices 10-1 to 10-7 to manage a communication network including the optical transmission devices 10-1 to 10-7. For example, when transmitting data from the optical transmission device 10-1 at one end of this communication network to the optical transmission device 10-7 at the other end, the optical transmission device 10-1 serves as a transmitting node and the optical transmission device 10-7 serves as a receiving node. The optical transmission devices 10-2 to 10-6 between these transmitting and receiving nodes are used as relay nodes. The optical transmission device 10-1 at the sending node converts data to be transmitted from an electrical signal to an optical signal of a predetermined wavelength inside a transponder (TPD: Transponder) 11, and sends this optical signal to an optical fiber cable 15. The optical transmission device 10-7 at the receiving node receives an optical signal from the optical fiber cable 15, and converts the optical signal to an electrical signal by the transponder 11 in the optical transmission device 10-7 to obtain the received data. When the distance of optical signal transmission becomes long, the optical intensity decreases, causing degradation of transmission quality such as bit error rate (BER). Furthermore, when the optical intensity decreases significantly and the bit error rate increases significantly, the optical transmission device 10-7 at the receiving node cannot correctly receive the transmitted data. Therefore, the optical transmission devices 10-2 to 10-6 of the relay nodes execute a predetermined relay process. Specifically, each relay node amplifies the optical intensity of the optical signal received at the respective relay position, and restores the original data without bit errors through a predetermined error correction process. However, in order to perform error correction processing, etc., it is necessary to perform electrical termination processing of the optical signal to be transmitted. Specifically, the optical transmission devices 10-2 to 10-6 convert the optical signal into an electrical signal in the transponder 11, and process the data of the obtained electrical signal to perform error correction processing, etc. Furthermore, the optical transmission devices 10-2 to 10-6 convert the processed electrical signal back into an optical signal, and send it to the downstream optical fiber cable 15 as a relay output. By performing the electrical termination process as described above, it is possible to reliably correct errors that occur during transmission and restore the optical intensity. It is also possible to obtain transmission quality data. However, a relatively large delay occurs in the signal inside the transponder 11 as a result of the electrical signal processing. Furthermore, as the transmission distance becomes longer, the number of relays increases, and the delay time increases. In the example of the optical transmission system 1A, optical transmission devices 10-3 and 10-5, each including the transponder 11, exist as relay nodes between the sending node and the receiving node, so the delay time is doubled compared to the case where relay processing including electrical termination is performed only once. In recent years, the functions of the optical fiber cable 15 and the transmitter that transmits the optical signal have been improved, so that it is possible to reduce the number of relays at relay nodes including electrical termination processing even in the case of relatively long-distance optical transmission. Therefore, the configuration of the optical transmission system 1A shown in Fig. 7 can be improved to that of the optical transmission system 1B shown in Fig. 8. FIG. 8 is a diagram showing an example of the configuration of an optical transmission system 1B which is an improvement over the optical transmission system 1A of FIG. 8, the optical transmission system 1B has a transponder 11 in the optical transmission devices 10-1 and 10-7, but the other optical transmission devices 10-2 to 10-6 do not have the transponder 11. In other words, when an optical signal is transmitted from the optical transmission device 10-1, which is the transmitting node, to the optical transmission device 10-7, which is the receiving node, no relay including electrical termination is performed on the way. Therefore, the delay time associated with the optical signal transmission in the optical transmission system 1B is significantly reduced compared to the optical transmission system 1A. In the optical transmission system 1B, since each of the optical transmission devices 10-2 to 10-6 does not have a transponder 11 and does not perform electrical termination processing, transmission quality data cannot be obtained at the relay node positions of each of the optical transmission devices 10-2 to 10-6. When a communication failure occurs, the network controller 20 usually divides the transmission section to narrow down the candidates for the location where the failure has occurred based on the transmission quality data detected at the position of each node used for transmitting the optical signal. However, in the case of the optical transmission system 1B, since the transmission quality data at the relay positions of each of the optical transmission devices 10-2 to 10-6 is not available, it is not possible to determine in which section between the output of the optical transmission device 10-1 and the input of the optical transmission device 10-7 the failure has occurred. As a result, it becomes difficult to identify the location where the failure has occurred, and it takes a long time to recover from the failure. In particular, when the distance of the optical fiber cable 15 is very long, it is difficult to find the location where the failure has occurred. <Multi-band networking technology> FIG. 9 is a diagram showing an example of the relationship between optical communication links and wavelength bands in multi-band networking technology. As shown in Figure 9, it is assumed that there are three types of optical wavelength bands used for communication: L-band, C-band, and S-band. The L-band is a wavelength band from 1565 to 1625 nm. The C-band is a wavelength band from 1530 to 1565 nm. The S-band is a wavelength band from 1460 to 1530 nm. In addition, the L band, the C band, and the S band each have an optical path independent of each other. In addition, in the example of Fig. 9, it is assumed that there are two optical communication links 31 and 32 that are independent of each other. The optical signals of each of the optical communication links 31 and 32 are adaptively band-switched according to the situation, and are switched so as to cross optical paths of multiple bands. The optical signal of the optical communication link 31 shown in Fig. 9 passes through an L-band optical path, is converted to a C-band optical signal by wavelength conversion, enters the C-band optical path, and is further converted to an S-band optical signal by wavelength conversion, enters the S-band optical path. This light is then converted to an L-band optical signal by wavelength conversion, enters the L-band optical path, and is converted to an electrical signal by Ph-EX (Photonic Exchange), processed, and output. Ph-EX is a component that minimizes electrical processing such as exchange, multiplexing, and switching. In addition, an optical signal of the optical communication link 32 having a C-band wavelength passes through a C-band optical path, is converted to an S-band optical signal by wavelength conversion, enters the S-band optical path, and is converted to an electrical signal in Ph-EX for processing. By using the technology shown in Fig. 9, optical transmission systems can efficiently use limited wavelength resources. Specifically, the traffic volume accommodated in the transmission path can be increased by about 30%. In addition, since electrical termination processing can be omitted at each communication node and optical signals can be processed as they are, effects such as power saving, large capacity, and low latency can be expected in the network. However, the optical transmission device at each node needs to be equipped with a function to convert the wavelength of optical signals. FIG. 10 is a diagram showing an example of the configuration of an optical transmission system 1 including an all-optical wavelength conversion unit 13. As shown in FIG. 10, the optical transmission system 1 includes five optical transmission devices 41, 42, 43, 44, and 45, and a network controller 20. The five optical transmission devices 41 to 45 are arranged in a line, for example, at locations spaced apart from each other by a certain distance. The optical transmission devices 41 to 45 are connected in series to each other via a single optical fiber cable 15 used as a transmission path for optical signals. The network controller 20 manages the entire optical communication network that is made up of the optical transmission devices 41 to 45 and the optical fiber cable 15. For example, when some kind of failure occurs on the optical communication network, the network controller 20 can generate information that is useful for identifying the location of the failure. For example, when transmitting data from an optical transmission device 41 at one end of this communication network to an optical transmission device 45 at the other end, the optical transmission device 41 serves as a transmitting node and the optical transmission device 45 serves as a receiving node. In addition, the optical transmission devices 42 to 44 between these transmitting and receiving nodes are each used as a relay node. The optical transmission device 41 at the sending node converts data to be transmitted from an electrical signal to an optical signal of a predetermined wavelength inside the transponder 11, and sends this optical signal to the optical fiber cable 15. The optical transmission device 45 at the receiving node receives the optical signal from the optical fiber cable 15, and converts the optical signal to an electrical signal in the transponder 11 within the optical transmission device 45 to obtain the received data. In the configuration shown in FIG. 10, an optical transmission device 43 used as one relay node includes an all-optical wavelength conversion unit 13 having an AO-WC (All Optical Wavelength Conversion) function. The all-optical wavelength conversion unit 13 in the optical transmission device 43 converts the wavelength of the input optical signal Oin having a wavelength of λ1 input from the optical fiber cable 15 to the optical transmission device 43 while keeping it as an optical signal, generates an optical signal having a wavelength of λ2 different from the input, and transmits it to the downstream optical fiber cable 15 as an outgoing optical signal Oo2 having a wavelength of λ2. The all-optical wavelength conversion unit 13 shown in FIG. 10 can also extract unnecessary optical components other than the optical main signal relayed inside the optical transmission device 43 and input them to the detector 11A in the optical transmission device 43. The detector 11A has the function of electrical termination processing like the transponder 11, but does not have the function of transmitting an optical signal. That is, the detector 11A has the function of converting the input optical signal into an electrical signal and the function of processing the electrical signal to detect transmission quality data. The optical transmission device 43 does not perform electrical termination processing on the optical main signal to be relayed, but relays the optical signal as it is and sends it to the downstream optical fiber cable 15, thereby preventing an increase in delay due to relay processing. Also, as will be described later, there is no need to use an optical splitter to extract the optical signal to be input to the detector 11A, so a decrease in the optical intensity of the optical main signal can be prevented. In addition, the all-optical wavelength conversion unit 13 extracts unnecessary optical components separate from the optical main signal being relayed and inputs them to the detector 11A in the optical transmission device 43, so that the detector 11A can detect transmission quality data at the node position of the optical transmission device 43. Therefore, the network controller 20 can obtain the transmission quality data of relay nodes that do not perform electrical termination processing, such as the optical transmission device 43. For example, when a fault occurs, the network controller 20 can determine whether or not a fault has occurred for each section based on the transmission quality data at the position of each relay node. <Configuration of all-optical wavelength conversion unit> FIG. 11 is a diagram showing an example of the configuration of the all-optical wavelength conversion unit 13 included in the optical transmission system 1 of FIG. As shown in FIG. 11, the all-optical wavelength conversion unit 13 includes a pumping light source 14, an optical fiber 15A, an optical multiplexer 16, a nonlinear optical medium 17, an optical demultiplexer 18, and an optical fiber 15B. The all-optical wavelength conversion unit 13 is an all-optical wavelength conversion device including a nonlinear optical medium 17 onto which both the optical main signal to be relayed and the pumping light emitted from the pumping light source 14 can be simultaneously incident. The pumping light source 14 generates pumping light Oe having a predetermined wavelength λe. The pumping light Oe generated by the pumping light source 14 passes through an optical fiber 15A and enters the optical multiplexer 16. The wavelength λe of the pumping light Oe is different from the wavelength λ1 of the input optical signal Oin. The optical intensity of the pumping light Oe is sufficiently greater than that of the input optical signal Oin. The optical multiplexer 16 generates light by multiplexing the input optical signal Oin input from the optical fiber cable 15 and the pump light Oe input from the optical fiber 15 A, and sends the light to the input end of the nonlinear optical medium 17 . The nonlinear optical medium 17 has nonlinear optical properties and can generate an optical signal with a wavelength different from that of the incident light. As a representative example, any one of highly nonlinear fiber (HNLF), periodically poled lithium niobate (PPLN), and a semiconductor optical amplifier (SOA) can be used as the nonlinear optical medium 17. The optical splitter 18 is connected to the light output side of the nonlinear optical medium 17, which is an all-optical wavelength conversion device. The output light Oout output from the output end of the nonlinear optical medium 17 is input to the optical splitter 18. The optical splitter 18 splits the incident light using its wavelength selection characteristics to extract two types of optical signals. That is, an outgoing optical signal Oo2 with a wavelength λ2 and an output light Oo1 with a wavelength λ1 are output from different output terminals of the optical splitter 18. The wavelength λ2 of the outgoing optical signal Oo2 is generated based on the wavelength of the input optical signal Oin, the wavelength λe of the pumping light Oe, and the nonlinear optical characteristics of the nonlinear optical medium 17. The input optical signal Oin with a wavelength λ1 passes through the nonlinear optical medium 17 together with the pumping light Oe, thereby generating the wavelength λ2 of the outgoing optical signal Oo2 that has been wavelength-converted. In addition, the light emitted from the nonlinear optical medium 17 also contains an optical component with the same wavelength λ1 as before the wavelength conversion. The outgoing optical signal Oo2 having a wavelength λ2 output from the optical demultiplexer 18 is sent as a relay output from the output of the optical transmission device 43 to the downstream optical fiber cable 15. Also, the outgoing light Oo1 having a wavelength λ1 output from the optical demultiplexer 18 is input to the detector 11A in the optical transmission device 43 via the optical fiber 15B. In this way, by using the all-optical wavelength converter 13 shown in Fig. 11, the wavelength of the optical main signal relayed by the optical transmission device 43 can be converted from λ1 to λ2 without electrical termination processing, and an increase in delay can be prevented. Also, the output light Oo1 of the same wavelength λ1 as that before the wavelength conversion output from the all-optical wavelength converter 13, i.e., unnecessary optical components other than the main signal, can be input to the detector 11A. The detector 11A internally converts the input output light Oo1 of wavelength λ1 into an electrical signal, and various processes can be performed in the form of the electrical signal. In this way, transmission quality data at the relay node position of the optical transmission device 43 can be obtained. However, the wavelength λ2 of the optical main signal sent by the relay node is different from the wavelength λ1 of the light other than the main signal input to the detector 11A. Therefore, the correlation between the transmission quality detected for the wavelength λ1 and the transmission quality detected for the wavelength λ2 is specified in advance, and the transmission quality data detected by the detector 11A is converted into the transmission quality data of the optical signal to be relayed based on the correlation. This conversion process may be performed inside the detector 11A or on the network controller 20 side. Experimental Demonstration of Cascadable PPLN-Based Inter-Band Wavelength Converters for Band-Switchable Multi-Band Optical Cross-Connect. The optical transmission system 1 shown in FIG. 10 provides a method for detecting an optical signal generated in the AO-WC of the optical node device before or after wavelength conversion. However, in the above method, since the input light intensity and output light intensity of the AO-WC are different, when actually introducing it as an optical node device, peripheral devices (optical attenuators and optical amplifiers) to adjust the light intensity are required. The present invention has been made in view of the above background, and an object of the present invention is to provide an optical transmission device and an optical transmission method capable of autonomously adjusting the output light intensity. In order to solve the above-mentioned problems, there is provided an optical transmission device that can be installed in at least one optical relay node of an optical transmission system in which an optical transmitting node capable of transmitting an optical signal and an optical receiving node capable of receiving an optical signal are connected via an optical transmission path, and one or more optical relay nodes are connected to an intermediate position of the optical transmission path, the optical transmission device comprising: an input optical intensity adjusting unit that adjusts the optical intensity of a transmission wavelength signal input to the optical relay node; a wavelength converting unit that converts the wavelength of the transmission wavelength signal whose optical intensity has been adjusted by the input optical intensity adjusting unit; a wavelength separating unit that separates the transmission wavelength signal to be relayed into the transmission wavelength signal having the same wavelength as before the wavelength conversion and a monitoring wavelength signal other than the transmission wavelength signal; an output optical intensity adjusting unit that adjusts the optical intensity of the transmission wavelength signal separated by the wavelength separating unit; a measurement unit that measures the transmission quality of the monitoring wavelength signal separated by the wavelength separating unit; and a control unit that controls the input optical intensity adjusting unit, the wavelength separating unit, and the output optical intensity adjusting unit. According to the present invention, it is possible to realize an optical transmission device and an optical transmission method capable of autonomously adjusting the output light intensity. FIG. 11 is a schematic diagram of an optical transmission device according to an embodiment of the present invention; FIG. 12 is a detailed diagram of an optical transmission device according to an embodiment of the present invention; FIG. 13 is a detailed diagram of an optical transmission device in which an optical amplifier is arranged in the optical transmission device according to the embodiment of the present invention; FIG. 14 is a flowchart showing an operation of outputting signal light wavelength-converted by a WSS of the optical transmission device according to an embodiment of the present invention to ports <2> to <n>; FIG. 15 is a configuration example of outputting signal light wavelength-converted by a WSS of the optical transmission device according to an embodiment of the present invention to port <1>; FIG. 16 is a flowchart showing an operation of outputting signal light wavelength-converted by a WSS of the optical transmission device according to an embodiment of the present invention to port <1>; FIG. 17 is a block diagram showing an example of a configuration of a general optical transmission system; FIG. 18 is a block diagram showing an example of a configuration of a general optical transmission system; FIG. 19 is a schematic diagram showing an example of a relationship between an optical communication link and a wavelength band in a multiband networking technology; FIG. 19 is a block diagram showing an example of a configuration of an optical transmission system according to an embodiment of the present invention; FIG. 19 is a block diagram showing an example of a configuration of an all-optical wavelength conversion unit included in the optical transmission system of FIG. Hereinafter, an optical transmission device and the like in an embodiment of the present invention (hereinafter, referred to as "the present embodiment") will be described with reference to the drawings. [overview] FIG. 1 is a schematic diagram of an optical transmission device according to an embodiment of the present invention. The optical transmission device according to this embodiment is applicable to the optical transmission system 1 in Fig. 10. The same components as those in Fig. 11 are denoted by the same reference numerals. The optical transmission device 100 is a transmission quality monitoring device that can be installed in at least one optical relay node of an optical transmission system 1 (Figure 10) in which an optical transmitting node capable of transmitting an optical signal and an optical receiving node capable of receiving an optical signal are connected via an optical transmission path, and one or more optical relay nodes are connected to intermediate positions of the optical transmission path. As shown in FIG. 1, the optical transmission device 100 includes a control unit 110, an optical input terminal 101, an optical output terminal 102, an input light power monitor 120 (input light power adjustment unit), a wavelength conversion unit 130, a wavelength selective switch (WSS) 140 (wavelength separation unit), a monitor measuring instrument 150 (measurement unit), and an output light power monitor 160 (output light power adjustment unit). The input optical power monitor 120 adjusts the optical power of a transmission wavelength signal input to an optical repeater node. Specifically, the input optical power monitor 120 adjusts the input optical power so that the input optical power is input to the wavelength converter 130 at an appropriate optical power. The wavelength conversion section 130 converts the wavelength of the transmission wavelength signal whose optical intensity has been adjusted by the input optical power monitor 120. The wavelength conversion section 130 also generates a monitoring wavelength signal from the transmission wavelength signal. The wavelength selective switch (WSS) 140 separates the transmission wavelength signal to be relayed into a transmission wavelength signal having the same wavelength as before the wavelength conversion and a monitoring wavelength signal (supervisory signal light) other than the transmission wavelength signal. The monitoring measuring instrument 150 measures the signal quality of the monitoring wavelength signal. The output light power monitor 160 adjusts the light power of the transmission wavelength signal separated by the WSS 140. The output light power monitor 160 also adjusts the output light power of the wavelength conversion unit . [Detailed configuration] Fig. 2 is a detailed configuration diagram of the optical transmission device 100 in Fig. 1. Fig. 2 shows a configuration example in which signal light wavelength-converted by the WSS 140 is output to ports <2> to <n>. <Control Unit 110> The control unit 110 determines whether the measured input light intensity Pin is greater than a preset maximum input light intensity Pmax, and adjusts the VOA 121 of the input light intensity monitor 120 so that Pin=Pmax or Pin<Pmax. The control unit 110 sets the maximum input light intensity to the nonlinear optical medium 131, and before the input side optical power meter 122 starts measurement, closes the input side optical shutter 124 to start measurement of the input light intensity by the input side optical power meter 122, controls the input light intensity monitor 120 so that the input light intensity measured by the input side optical power meter 122 is equal to or less than the maximum input light intensity, and after adjustment by the input light intensity monitor 120 is completed, opens the input side optical shutter 124. In addition, before the output side optical power meter 162 starts measurement, the control unit 110 closes the output side optical shutter 164 to start measurement of the output light intensity by the output side optical power meter 162, controls the output light intensity monitor 160 so that the output light intensity measured by the output side optical power meter 162 becomes a predetermined output light intensity, and opens the output side optical shutter 164 after adjustment by the output side optical power monitor 160 is completed. <Input Light Intensity Monitor 120> In FIG. 2, an input light intensity monitor 120 adjusts the input light intensity so that the input light is input to a wavelength conversion section 130 at an appropriate light intensity. The input light intensity monitor 120 includes a VOA (Variable Optical Attenuator) 121 , an input side optical power meter 122 , a beam splitter 123 , and an input side optical shutter 124 . The VOA 121 variably attenuates the intensity of the optically transmitted optical signal upon receiving an instruction from the control unit 110 (receiving a control signal / voltage control signal from the control unit 110, the same applies below). The VOA 121 performs power management within the input optical power monitor 120 by voltage control from the control unit 110. The VOA 121 corresponds to wavelengths of, for example, C band, L band, and C+L band (FIG. 9). The input side optical power meter 122 measures the intensity (power) of light. The input side optical power meter 122 measures the output of the wavelength light source in the input optical power monitor 120 here. The beam splitter 123 splits an optical signal from one input channel into two or more optical signals. Here, the beam splitter 123 splits an optical signal from the VOA 121 connected to the optical input terminal 101 port <1> into an optical signal output to the wavelength conversion unit 130 and an optical signal output to the input side optical power meter 122. Note that the wavelength and power do not change after splitting by the beam splitter 123. The input-side optical shutter 124 performs high-speed optical shutter control (control to transmit light only at specified times and block light at other times) under voltage control from the control unit 110. The input-side optical shutter 124 prevents light from being input to the wavelength conversion unit 130 at the light intensity before adjustment is completed. <Wavelength conversion unit 130> The wavelength conversion unit 130 is a wavelength signal duplication functional unit that generates a monitoring wavelength signal (supervisory signal light) from a transmission wavelength signal. The wavelength conversion section 130 includes a nonlinear optical medium 131 , a pumping light source 132 , and an optical multiplexer 133 . The wavelength conversion section 130 is an all-optical wavelength conversion device including a nonlinear optical medium 131 onto which both the optical main signal to be relayed and the pumping light emitted from a pumping light source 132 can be simultaneously incident. The pumping light source 132 receives an instruction from the control unit 110 and generates pumping light Oe of a predetermined wavelength λe. The pumping light Oe generated by the pumping light source 132 passes through the optical fiber 15A and enters the optical multiplexer 133. The wavelength λe of the pumping light Oe is different from the wavelength λ1 of the input optical signal Oin. Furthermore, the optical intensity of the pumping light Oe is sufficiently greater than that of the input optical signal Oin. The optical multiplexer 133 generates light by multiplexing the input optical signal Oin input from the optical fiber cable 15 and the pump light Oe input from the optical fiber 15 A, and sends the light to the input end of the nonlinear optical medium 131 . The nonlinear optical medium 131 has nonlinear optical properties and can generate an optical signal with a wavelength different from that of the incident light. As a representative example, any one of highly nonlinear fiber (HNLF), periodically poled lithium niobate (PPLN), and a semiconductor optical amplifier (SOA) can be used as the nonlinear optical medium 131. <Wavelength Selective Switch (WSS) 140> The WSS 140 is connected to the light output side of the nonlinear optical medium 131, which is an all-optical wavelength conversion device. The WSS 140 includes an optical demultiplexer (not shown), which receives instructions from the control unit 110, demultiplexes the incident light using wavelength selection characteristics, and extracts two types of optical signals. The WSS 140 outputs an output optical signal Oo2 with a wavelength λ2 and an output light Oo1 with a wavelength λ1 from a plurality of mutually different ports <1>, <2>, ..., <n>. The wavelength λ2 of the outgoing optical signal Oo2 is generated based on the wavelength of the input optical signal Oin, the wavelength λe of the pumping light Oe, and the nonlinear optical characteristics of the nonlinear optical medium 131. The input optical signal Oin with a wavelength λ1 passes through the nonlinear optical medium 131 together with the pumping light Oe, thereby generating the wavelength λ2 of the outgoing optical signal Oo2 that has been wavelength-converted. In addition, the outgoing light from the nonlinear optical medium 131 also contains an optical component with the same wavelength λ1 as before the wavelength conversion. The outgoing optical signal Oo2 having a wavelength λ2 output from the WSS 140 is sent as a relay output to the optical fiber cable 15 downstream from the output of the optical transmission device 100. In addition, the outgoing light Oo1 having a wavelength λ1 output from the WSS 140 is input to the monitoring measuring instrument 150 via the optical fiber 15B. <Monitor Measuring Instrument 150> The monitoring measuring instrument 150 measures the signal quality of the monitoring wavelength signal (monitoring signal light). The monitor measuring instrument 150 is a receiver 151 (more specifically, a detector provided in the receiver) of the optical transmission device 100 (hereinafter, this detector will be referred to as the receiver 151). The receiver 151 corresponds to, for example, the receiving section of a transponder (TPD). Like a transponder, it has an electrical termination function, but does not have the function of transmitting an optical signal. The receiver 151 has a function of converting an input optical signal into an electrical signal, and a function of processing this electrical signal to detect transmission quality data. The receiver equivalent to the transponder receiving section converts unnecessary light into an electrical signal and processes it to obtain transmission quality data. The receiver 151 may also be a spectrum analyzer, a polarization monitor, or a power meter. A spectrum analyzer is an electrical measuring instrument that displays a two-dimensional graph on a screen with frequency on the horizontal axis and power or voltage on the vertical axis. In the case of a spectrum analyzer, the signal-to-noise ratio is obtained. In the case of a polarization monitor, the polarization state of the optical signal is obtained, and in the case of a power meter, the optical intensity is obtained. 2, the monitor measuring instrument 150 measures the signal light outputted to ports <2>, ..., <n> and wavelength-converted by the WSS. The receiver 151 may be provided for each port <2>, ..., <n>, or may be shared for multiple ports. The receiver 151 may also be a combination of multiple types of measuring instruments. <Output Light Intensity Monitor 160> The output optical intensity monitor 160 includes a VOA 161 , an output-side optical power meter 162 , a beam splitter 163 , and an output-side optical shutter 164 . The VOA 161 variably attenuates the intensity of the optically transmitted optical signal under instructions from the control unit 110. The VOA 161 performs power management within the output optical power monitor 160 by voltage control from the control unit 110. The output side optical power meter 162 measures the intensity (power) of the light incident on the output optical power monitor 160 . The beam splitter 163 splits an optical signal from one input channel into two or more optical signals. Here, the beam splitter 163 splits the optical signal from the VOA 161 connected to the port <1> into an optical signal output to the optical output terminal 102 and an optical signal output to the output side optical power meter 162. The output-side optical shutter 164 performs high-speed optical shutter control under voltage control from the control unit 110. The output-side optical shutter 164 prevents light from being output to the outside at the light intensity before adjustment is completed. Fig. 3 is a detailed configuration diagram in which an optical amplifier 171 is arranged in the optical transmission device 100 in Fig. 2. The same components as in Fig. 2 are denoted by the same reference numerals. 3, an optical amplifier 171 that amplifies the output of the input light power monitor 120 is disposed on the output side of the input light power monitor 120 (before the wavelength conversion unit 130). Also, an optical amplifier 171 that amplifies the output of the WSS 140 is disposed at each of ports <1>, <2>, ..., <n> of the WSS 140. 3, when the conversion efficiency / gain of the input light power monitor 120 is low, an optical amplifier 171 is added to the output side of the input light power monitor 120 (preceding the wavelength conversion unit 130) to amplify the output light of the input light power monitor 120. Also, when the conversion efficiency / gain of the nonlinear optical medium 131 is low, the optical transmission device 100 adds an optical amplifier 171 to amplify the output light of the nonlinear optical medium 131. Note that only one of the optical amplifier 171 on the output side of the input light power monitor 120 and the optical amplifier 171 on the output side of the nonlinear optical medium 131 may be disposed in accordance with the above conversion efficiency / gain. The operation of the optical transmission device 100 configured as above will now be described. [Example of operation in which signal light wavelength-converted by the WSS is output to ports <2> to <n>] FIG. 4 is a flowchart showing an operation of outputting the signal light wavelength-converted by the WSS of the optical transmission device 100 shown in FIG. 2 to the ports <2> to <n>. In step S1, the control unit 110 sets the maximum input light intensity Pmax to the nonlinear optical medium 131, which is a specification within the optical transmission device 100, using an input unit (not shown). In step S2, the operator sets the pre-input information (the wavelength setting of the channel to be monitored and the output optical power Pout). Here, the wavelength setting of the channel to be monitored is set so that the signal light wavelength-converted by the WSS is output to ports <2> to <n>. In step S 3 , the input light intensity monitor 120 measures the input light intensity Pin using the input side optical power meter 122 . In step S4, the control unit 110 determines whether the measured input light intensity Pin is greater than a preset maximum input light intensity Pmax (Pin>Pmax). If Pin>Pmax (S4: Yes), in step S5, the control unit 110 adjusts the VOA 121 of the input light intensity monitor 120 so that Pin=Pmax or Pin<Pmax. If Pin≦Pmax (S4: No), the process proceeds directly to step S6. Here, in wavelength conversion by the nonlinear optical medium 131, when high input light intensity is input, degradation of transmission quality occurs due to nonlinear phenomena such as gain saturation and inter-channel crosstalk. In this embodiment, in order to suppress degradation of transmission quality due to nonlinear phenomena, the maximum input light intensity Pmax to the nonlinear optical medium 131 is set in advance. In step S6, the control unit 110 opens the input-side optical shutter 124 of the input light intensity monitor 120. As a result, as shown by the outlined waveforms indicated above the arrows of the input light signal Oin in Fig. 2, the input light signals Oin of each component of wavelengths λ1 to λn (hereinafter simply referred to as input light signals of wavelengths λ1 to λn) are input from the input light intensity monitor 120 to the optical multiplexer 133 of the wavelength conversion unit 130 through the optical fiber cable 15. Note that in order to indicate that the wavelength of the input light signal Oin in Fig. 2 is not a single wavelength, the outlined waveforms are indicated by rectangles (the same applies to the notation method of wavelength-converted signal light described later). In step S7, the pumping light source 14 generates pumping light Oe of a single wavelength λe, and inputs the pumping light Oe of wavelength λe to the optical multiplexer 133 through the optical fiber 15A. In step S8, the optical multiplexer 133 multiplexes the input optical signal Oin having wavelengths λ1 to λn of the input optical power monitor 120 and the pumping light Oe from the pumping light source 14, and inputs the multiplexed signal to the nonlinear optical medium 131. The optical intensity of the pumping light Oe is sufficiently greater than that of the input optical signal Oin. In step S9, the nonlinear optical medium 131 of the wavelength conversion unit 130 passes both the input optical signal Oin with wavelengths λ1 to λn and the pumping light Oe with wavelength λe, and generates signal light Oo2 obtained by converting the wavelength of the input optical signal Oin with wavelengths λ1 to λn in mirror symmetry with the pumping light Oe as the center wavelength based on the nonlinear optical characteristics of the nonlinear optical medium 131, and also outputs the wavelength-converted signal light Oo2 and the optical component Oo1 with the same wavelengths λ1 to λn as before the wavelength conversion. That is, the output light Oout of the nonlinear optical medium 131 also contains the wavelength-converted signal light Oo2 (see the hatched waveform indicated above the arrow of the output light Oout in FIG. 2) and the optical component Oo1 with the same wavelengths λ1 to λn as before the wavelength conversion (see the outlined waveform indicated above the arrow of the output light Oout in FIG. 2). The output light Oout output from the nonlinear optical medium 131 contains optical components Oo1 with wavelengths λ1 to λn, a wavelength λe, and wavelength-converted signal light Oo2. The wavelength-converted signal light Oo2 is a component generated by wavelength conversion of the input optical signal Oin accompanying passage through the nonlinear optical medium 131. The optical intensity of the wavelength-converted signal light Oo2 component included in the output light Oout depends on the nonlinear optical medium and the pumping light intensity, and can be made equivalent to that of the input optical signal Oin. For this reason, wavelength conversion can be performed without attenuating the optical intensity. Furthermore, the optical intensity of the optical component Oo1 of wavelengths λ1 to λn contained in the output light Oout is equivalent to that of the input optical signal Oin. Therefore, an optical signal other than the main signal and having the same wavelengths λ1 to λn as before the wavelength conversion can be extracted from the output of the nonlinear optical medium 131 with sufficiently large optical intensity. In step S10, the WSS 140 transmits the wavelength-converted optical signal Oo2 to ports <2> to <n> as a supervisory optical signal, and transmits the outgoing optical signal Oo1 to port <1> of the monitor channel. In step S11, the control unit 110 adjusts the output optical signal Oo1 to Pout at the VOA 161 while measuring the output optical power meter 162 (the output optical shutter 164 is closed). In step S 12 , the control unit 110 opens the output-side optical shutter 164 of the output light intensity monitor 160 . In step S13, each receiver 151 of the monitor measuring instrument 150 measures the transmission quality of the monitoring signal light Oo2 transmitted to ports <2> to <n>, obtains the measurement data, and transmits the measurement data to the control unit 110, thereby completing the processing of this flow. Here, since a supervisory optical signal Oo2 having a sufficiently high optical intensity is input to each receiver 151, each receiver 151 can easily detect the transmission quality data at the position of the corresponding relay node. The above flow procedure makes it possible to adjust the output light intensity. It is also possible to make the output light intensity the same as the input light intensity. [Example of operation in which signal light wavelength-converted by the WSS is output to port <1>] 5 shows an example of a configuration in which the signal light wavelength-converted by the WSS 140 is output to a port <1>. The same components as those in FIG. 2 are denoted by the same reference numerals. Fig. 6 is a flowchart showing an operation of outputting the signal light wavelength-converted by the WSS of the optical transmission device 100 shown in Fig. 5 to the port <1>. The same processing parts as those in Fig. 4 are assigned the same reference numerals, and the description of the overlapping parts will be omitted. Step S2A replaces step S2 in Fig. 4. In step S2A, the operator sets pre-input information (wavelength setting of the channel to be monitored and output optical power Pout). Here, the wavelength setting of the channel to be monitored is set so that the signal light wavelength-converted by the WSS is output to port <1>. Step S10A replaces step S10 in Fig. 4. In step S10A, the WSS 140 transmits the wavelength-converted signal light Oo2 to port <1> as the outgoing optical signal Oo1, and transmits the outgoing optical signal Oo2 having the same wavelengths λ1 to λn as before the wavelength conversion to ports <2> to <n> of the monitor channel as supervisory signal light. The above flow procedure makes it possible to adjust the output light intensity. It is also possible to make the output light intensity the same as the input light intensity. In addition, since the light after wavelength conversion is used as a transmission signal light, the device can be used as both a monitoring device and a wavelength converter. [effect] As described above, the optical transmission device 100 (FIGS. 1, 2, 3, and 5) can be installed in at least one optical relay node of the optical transmission system 1 (FIG. 10) in which an optical transmitting node capable of transmitting an optical signal and an optical receiving node capable of receiving an optical signal are connected via an optical transmission line, and one or more optical relay nodes are connected to intermediate positions of the optical transmission line. The optical transmission device 100 includes an input optical intensity adjuster (input optical intensity monitor 120) that adjusts the optical intensity of a transmission wavelength signal input to the optical relay node, and a wavelength converter that converts the wavelength of the transmission wavelength signal whose optical intensity has been adjusted by the input optical intensity adjuster. the wavelength conversion unit 130 converting the wavelength of the transmission wavelength signal into a wavelength signal having the same wavelength as that before the wavelength conversion, a wavelength separation unit (WSS 140) separating the transmission wavelength signal to be relayed into a transmission wavelength signal having the same wavelength as that before the wavelength conversion and a monitoring wavelength signal other than the transmission wavelength signal, an output light intensity adjustment unit (output light intensity monitor 160) adjusting the light intensity of the transmission wavelength signal separated by the wavelength separation unit, a measurement unit (monitor measurement instrument 150) measuring the transmission quality of the monitoring wavelength signal separated by the wavelength separation unit, and a control unit 110 controlling the input light intensity adjustment unit, the wavelength separation unit, and the output light intensity adjustment unit. In this way, the input light intensity adjustment unit (input light intensity monitor 120) can appropriately adjust the input light intensity to suppress the deterioration of the transmission quality. The wavelength conversion unit 130 generates a monitoring wavelength signal from the transmission wavelength signal. The output light intensity adjustment unit (output light intensity monitor 160) appropriately outputs the light intensity of the output transmission wavelength signal. The measurement unit (monitoring measurement device 150) measures the transmission quality of the monitoring wavelength signal. Each of these functional units is controlled by the control unit 110. Therefore, it is possible to realize a transmission quality monitoring device that can autonomously adjust the output light intensity. In this way, the optical transmission device 100 can minimize the deterioration of the transmission performance of the transmission wavelength signal or eliminate the need for readjustment of the optical level diagram. As a result, it is possible to introduce the optical transmission device 100 while minimizing the impact on existing optical transmission devices. In addition, the optical transmission device 100 relays the relayed transmission wavelength signal as an optical signal without electrical termination and sends it to the downstream optical fiber cable 15, so that it is possible to prevent an increase in delay due to relay processing. In addition, since it is not necessary to use an optical splitter to extract the optical signal to be input to the measurement unit (monitoring measuring instrument 150), it is possible to suppress a decrease in the optical intensity of the transmission wavelength signal. Therefore, the control unit 110 can obtain transmission quality data of relay nodes such as optical transmission devices that do not perform electrical termination processing. For example, when a fault occurs, the control unit 110 can distinguish whether or not a fault has occurred for each section based on the transmission quality data at the position of each relay node. In addition, the optical transmission device 100 can also replace the transmission wavelength signal with the wavelength-converted signal light by the control unit 110 setting each port <1>, <2>, ..., <n> of the WSS 140. For example, the optical transmission device 100 transmits each optical component of wavelengths λ1 to λn, detects each optical component of the wavelength-converted signal light as a monitoring wavelength signal, and acquires transmission quality data (FIGS. 2, 3, and 4). In addition, the optical transmission device 100 transmits each optical component of wavelengths λ1 to λn, detects each optical component of wavelengths λ1 to λn as an extraction signal, and acquires transmission quality data (FIGS. 5 and 6). In this case, the optical transmission device 100 can acquire transmission quality data even when wavelength conversion is not performed. In other words, since the light after wavelength conversion is used as the transmission signal light, it can be used as both a monitoring device and a wavelength converter. The optical transmission device 100 (Figures 1, 2, 3, 5) is provided with an excitation light source 132 (Figures 2, 3, 5) that emits excitation light of a wavelength different from the wavelength before wavelength conversion of the transmission wavelength signal to be relayed, and the wavelength conversion unit 130 is a nonlinear optical medium 131 (Figures 2, 3, 5) into which both the transmission wavelength signal to be relayed and the excitation light emitted from the excitation light source 132 can be simultaneously incident, and the wavelength separation unit (WSS 140) separates the emitted light from the nonlinear optical medium 131 into an optical component with a wavelength after wavelength conversion and an optical component with a wavelength before wavelength conversion. In this way, the optical intensity of the wavelength-converted signal light component contained in the output light Oout (FIGS. 2, 3, and 5) from the nonlinear optical medium 131 depends on the nonlinear optical medium 131 and the pump light intensity, and can be made equivalent to that of the input optical signal Oin. Therefore, wavelength conversion can be performed without attenuating the optical intensity. Furthermore, the optical intensity of the optical components with wavelengths λ1 to λn contained in the output light Oout is equivalent to that of the input optical signal Oin. Therefore, optical signals other than the main signal and with the same wavelengths λ1 to λn as before the wavelength conversion can be extracted from the output of the nonlinear optical medium 131 with sufficiently large optical intensity. The input light intensity adjustment unit (input light intensity monitor 120) is characterized in that it comprises an input-side optical shutter 124 (FIGS. 2, 3, 5) that blocks the input of a transmission wavelength signal so that the transmission wavelength signal is not input to the wavelength conversion unit 130 at the optical intensity before adjustment is completed, and the output light intensity adjustment unit (output light intensity monitor 160) is characterized in that it comprises an output-side optical shutter 164 (FIGS. 2, 3, 5) that blocks the output of a transmission wavelength signal so that the transmission wavelength signal is not output at the optical intensity before adjustment is completed. In this manner, the input light intensity monitor 120 and the output light intensity monitor 160 have an input side optical shutter 124 and an output side optical shutter 164, and thus can perform input light intensity adjustment and output light intensity adjustment in an environment in which the optical transmission path is temporarily closed to prevent unwanted input and output (FIGS. 4 and 6). In the optical transmission device 100 (FIGS. 1, 2, 3, 5), the input light intensity adjusting unit (input light intensity monitor 120) includes an input side adjusting unit (VOA 121) (FIGS. 2, 3, 5) that adjusts the input light intensity to a nonlinear optical medium 131, an input side optical power meter 122 (FIGS. 2, 3, 5) that measures the input light intensity, and an input side optical shutter 124 (FIGS. 2, 3, 5) that blocks the input of a transmission wavelength signal, and the control unit 110 (FIGS. 2, 3, 5) sets a maximum input light intensity to the nonlinear optical medium 131, closes the input side optical shutter 124 before the input side optical power meter 122 starts measurement, starts measurement of the input light intensity by the input side optical power meter 122, controls the input side adjusting unit so that the input light intensity measured by the input side optical power meter 122 is equal to or less than the maximum input light intensity, and opens the input side optical shutter 124 after adjustment by the input side adjusting unit is completed. In this way, the input light intensity adjustment can be performed (FIGS. 4 and 6) in an environment where unnecessary input to the optical transmission device 100 is prevented, and the input light intensity adjustment can be performed accurately. In the optical transmission device 100 (FIGS. 1, 2, 3, and 5), the output light intensity adjusting unit (output light intensity monitor 160) includes an output side adjusting unit (VOA 161) (FIGS. 2, 3, and 5) that adjusts the amount of light output so that the output light intensity becomes a predetermined output light intensity, an output side optical power meter 162 that measures the output light intensity, and an output side optical shutter 164 that blocks the output of a transmission wavelength signal, and the control unit 110 is characterized in that before the output side optical power meter 162 starts measurement, the control unit 110 closes the output side optical shutter 164 to start measurement of the output light intensity by the output side optical power meter 162, controls the output side adjusting unit so that the output light intensity measured by the output side optical power meter 162 becomes the predetermined output light intensity, and opens the output side optical shutter 164 after adjustment by the output adjusting unit is completed. By doing this, adjustments of the input light intensity and the output light intensity can be performed (Figures 4 and 6) in an environment where emission from the optical transmission device 100 is prevented, thereby suppressing the impact on downstream optical transmission devices, etc. The optical transmission device 100 (FIGS. 1, 2, 3, and 5) is characterized in that an optical amplifier 171 (FIG. 3) that amplifies signal light is disposed on the output side of the input light intensity adjustment unit (input light intensity monitor 120) and / or on the output side of the wavelength separation unit (WSS 140). In this way, when the input light intensity is low, the input light can be amplified by arranging the optical amplifier 171 on the output side of the input light intensity monitor 120. Also, when the gain / conversion efficiency of the nonlinear optical medium 131 is low, the output light can be amplified by arranging the optical amplifier 171 immediately after the output from the WSS 140. In addition, in the network controller 20 (FIG. 10) of the optical transmission system 1, it is generally assumed that the "Pre-FEC BER" ​​is used as the transmission quality data detected by the transponder 11 of each optical relay node. Meanwhile, the detector 11A and the transponder 11 can obtain data such as the chromatic dispersion compensation amount, the polarization mode dispersion, and the polarization dependent loss in addition to the "Pre-FEC BER" ​​by electrical signal processing of the communication data. Therefore, the network controller 20 can collect data such as the chromatic dispersion compensation amount, the polarization mode dispersion, and the polarization dependent loss from each optical relay node in which the detector 11A or the transponder 11 is implemented, and use the data as learning data for machine learning. This helps to realize failure prediction in an optical network without electrical termination processing. Furthermore, among the processes described in the above embodiments, all or part of the processes described as being performed automatically can be performed manually, or all or part of the processes described as being performed manually can be performed automatically by a known method. In addition, the information including the processing procedures, control procedures, specific names, various data and parameters shown in the above documents and drawings can be changed arbitrarily unless otherwise specified. In addition, each component of each device shown in the figure is a functional concept, and does not necessarily have to be physically configured as shown in the figure. In other words, the specific form of distribution and integration of each device is not limited to that shown in the figure, and all or part of them can be functionally or physically distributed and integrated in any unit depending on various loads, usage conditions, etc. In addition, the above-mentioned configurations, functions, processing units, processing means, etc. may be realized in part or in whole by hardware, for example, by designing them as integrated circuits. In addition, the above-mentioned configurations, functions, etc. may be realized by software for a processor to interpret and execute a program that realizes each function. Information on the programs, tables, files, etc. that realize each function can be stored in a memory, a recording device such as a hard disk or SSD (Solid State Drive), or a recording medium such as an IC (Integrated Circuit) card, an SD (Secure Digital) card, or an optical disk. 1. Optical transmission system 10-1, 10-2, 10-3, 10-4, 10-5 Optical transmission equipment 11 Transponder 11A Detector 13 All-optical wavelength conversion unit 14 Excitation light source 15 Optical fiber cable 15A, 15B Optical fiber 16 Optical multiplexer 17 Nonlinear Optical Media 18 Optical demultiplexer 20 Network Controller 31, 32 Optical communication link 100 Optical transmission device 110 Control unit 101 Optical input terminal 102 Optical output terminal 120 Input light intensity monitor (input light intensity adjustment unit) 121,161 VOA 122 Input side optical power meter 123, 163 Beam splitter 124 Input side optical shutter 130 Wavelength conversion unit 131 Nonlinear optical media 132 Excitation light source 133 Optical multiplexer 140 Wavelength selective switch (WSS) (wavelength separation section) 150 Monitor measuring device (measuring part) 151 Receiver 160 Output light intensity monitor (output light intensity adjustment unit) 162 Output side optical power meter 164 Output side optical shutter 171 Optical amplifier

Claims

1. An optical transmission device that can be installed in at least one optical repeater node of an optical transmission system in which an optical transmitting node capable of transmitting an optical signal and an optical receiving node capable of receiving an optical signal are connected via an optical transmission line, and one or more optical repeater nodes are connected to intermediate positions of the optical transmission line, an input optical intensity adjusting unit that adjusts the optical intensity of a transmission wavelength signal input to the optical repeater node; a wavelength conversion unit that converts the wavelength of the transmission wavelength signal whose optical intensity has been adjusted by the input optical intensity adjustment unit; a wavelength separation unit that separates the transmission wavelength signal to be relayed into the transmission wavelength signal having the same wavelength as that before wavelength conversion and a monitoring wavelength signal other than the transmission wavelength signal; an output light intensity adjusting unit that adjusts the light intensity of the transmission wavelength signal separated by the wavelength separating unit; a measurement unit that measures the transmission quality of the monitoring wavelength signal separated by the wavelength separation unit; a control unit that controls the input light intensity adjustment unit, the wavelength separation unit, and the output light intensity adjustment unit. An optical transmission device characterized by:

2. a pumping light source that emits pumping light of a wavelength different from the wavelength of the transmission wavelength signal to be relayed before wavelength conversion; the wavelength conversion unit is a nonlinear optical medium into which both the transmission wavelength signal to be relayed and the pumping light emitted from the pumping light source can be simultaneously incident, the wavelength separation unit separates the output light from the nonlinear optical medium into a light component having a wavelength after wavelength conversion and a light component having a wavelength before wavelength conversion.

2. The optical transmission device according to claim 1.

3. the input light intensity adjustment unit includes an input-side optical shutter that blocks the input of the transmission wavelength signal so that the transmission wavelength signal is not input to the wavelength conversion unit at an optical intensity before adjustment is completed; The output light intensity adjustment unit includes an output-side optical shutter that blocks the output of the transmission wavelength signal so that the transmission wavelength signal is not output at an optical intensity before adjustment is completed.

3. The optical transmission device according to claim 2.

4. The input light intensity adjustment unit an input side adjusting unit that adjusts the intensity of light input to the nonlinear optical medium; an input-side optical power meter for measuring the input optical intensity; an input-side optical shutter that blocks the input of the transmission wavelength signal, The control unit setting a maximum input light intensity to the nonlinear optical medium; before starting measurement by the input-side optical power meter, the input-side optical shutter is closed and measurement of the input light intensity by the input-side optical power meter is started; controlling the input-side adjusting unit so that the input light intensity measured by the input-side optical power meter is equal to or less than the maximum input light intensity; After the adjustment by the input side adjustment unit is completed, the input side optical shutter is opened.

3. The optical transmission device according to claim 2.

5. The output light intensity adjustment unit an output side adjusting unit that adjusts the amount of light output so that the output light intensity becomes a predetermined output light intensity; an output-side optical power meter for measuring the output optical intensity; an output-side optical shutter that blocks the output of the transmission wavelength signal, The control unit before starting measurement by the output-side optical power meter, closing the output-side optical shutter and starting measurement of the output light intensity by the output-side optical power meter; controlling the output-side adjusting unit so that the output light intensity measured by the output-side optical power meter becomes a predetermined output light intensity; After the output-side adjustment unit completes the adjustment, the output-side optical shutter is opened.

3. The optical transmission device according to claim 2.

6. An optical amplifier for amplifying the signal light is disposed on the output side of the input light intensity adjuster and / or the output side of the wavelength demultiplexer.

2. The optical transmission device according to claim 1.

7. An optical transmission method for an optical transmission system in which an optical transmitting node capable of transmitting an optical signal and an optical receiving node capable of receiving an optical signal are connected via an optical transmission line, and one or more optical repeater nodes are connected to an intermediate position of the optical transmission line, comprising: The optical repeater node of the optical transmission system comprises: a step of adjusting the optical intensity of a transmission wavelength signal input to the optical repeater node; converting the wavelength of the transmission wavelength signal with the optical intensity adjusted; a step of dividing the transmission wavelength signal to be relayed into the transmission wavelength signal having the same wavelength as that before wavelength conversion and a monitoring wavelength signal other than the transmission wavelength signal; adjusting the optical intensity of the separated transmission wavelength signals; and measuring the transmission quality of the separated monitoring wavelength signal. An optical transmission method comprising:

8. An optical transmission device that can be installed in at least one optical repeater node of an optical transmission system in which an optical transmitting node capable of transmitting an optical signal and an optical receiving node capable of receiving an optical signal are connected via an optical transmission line, and one or more optical repeater nodes are connected to intermediate positions of the optical transmission line, an input optical intensity adjusting unit that adjusts the optical intensity of a transmission wavelength signal input to the optical repeater node; a wavelength conversion unit that converts the wavelength of the transmission wavelength signal whose optical intensity has been adjusted by the input optical intensity adjustment unit; a wavelength separation unit that separates the transmission wavelength signal to be relayed into a monitoring wavelength signal having the same wavelength as that before wavelength conversion and the transmission wavelength signal that is signal light after wavelength conversion; an output light intensity adjusting unit that adjusts the light intensity of the transmission wavelength signal separated by the wavelength separating unit; a measurement unit that measures the transmission quality of the monitoring wavelength signal separated by the wavelength separation unit; a control unit that controls the input light intensity adjustment unit, the wavelength separation unit, and the output light intensity adjustment unit. An optical transmission device characterized by:

9. An optical transmission method for an optical transmission system in which an optical transmitting node capable of transmitting an optical signal and an optical receiving node capable of receiving an optical signal are connected via an optical transmission line, and one or more optical repeater nodes are connected to an intermediate position of the optical transmission line, comprising: The optical repeater node of the optical transmission system comprises: a step of adjusting the optical intensity of a transmission wavelength signal input to the optical repeater node; converting the wavelength of the transmission wavelength signal with the optical intensity adjusted; a step of dividing the transmission wavelength signal to be relayed into a monitoring wavelength signal having the same wavelength as that before wavelength conversion and the transmission wavelength signal which is signal light after wavelength conversion; adjusting the optical intensity of the separated transmission wavelength signals; and measuring the transmission quality of the separated monitoring wavelength signal. An optical transmission method comprising: