JP2013046166A - Optical transmitter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inspect the connection relation of an optical transceiver and an ROADM switch instantaneously in an ROADM system.SOLUTION: In an ROADM switch having a plurality of I/O ports, an arbitrary wavelength component of an optical signal input from an arbitrary input side of the I/O ports is modulated by an identification pattern of the I/O port, and output as the return light to the output side of the I/O port. In an optical transceiver having transmitted an optical signal to the ROADM switch, a connection detection unit for detecting an identification pattern by receiving the return light is provided, and the ROADM switch connected with the optical transceiver and the I/O port thereof are determined.

Description

  The present invention relates to an optical transmission apparatus capable of inspecting a connection relationship between an optical transceiver and a wavelength selective switch.

  A ROADM (Reconfigurable Optical Add / Drop Multiplexer) system is used to construct an optical core network between urban areas and cities. In the ROADM system, a plurality of nodes at distant points are connected to each other via an optical transmission path, and the path of an optical signal is switched in units of wavelengths at each node.

  FIG. 1 shows a configuration example of an optical transmission apparatus that constructs a node of a ROADM system. In the case of FIG. 1, the node 1 is connected to another three nodes via three optical transmission line pairs 21 to 23. Each of these three optical transmission line pairs 21 to 23 is composed of two optical transmission lines corresponding to uplink and downlink.

  In the node 1, there are three ROADM switches 31 to 33 having a plurality of input / output ports, which are connected to the optical transmission line pairs 21 to 23 described above. The configuration of the three ROADM switches 31 to 33 is the same. However, the number of input / output ports is not necessarily the same depending on the number of optical transmission line pairs and optical transceivers to be connected.

  As an example, the configuration of the ROADM switch 31 connected to the optical transmission line pair 21 will be described. The ROADM switch 31 is provided with a plurality of input / output ports 201 to 205. The input / output port 201 has an optical transmission line pair 21, the input / output port 202 has an optical transmitter / receiver 51, the input / output port 203 has an optical transmitter / receiver 54, the input / output port 204 has another ROADM switch 32, and an input / output port 205. Is connected to another ROADM switch 33. The optical transmission line pair 23 may be connected to the input / output port 205 without going through the ROADM switch 33.

  The ROADM switch 31 can switch the output destination (output port) of the input optical signal in units of wavelengths. Thereby, the ROADM switch 31 can freely transmit and receive optical signals in units of wavelengths between the optical transmission line pair 21, the optical transceivers 51 and 54, and the other ROADM switches 32 and 33. However, depending on the internal configuration of the ROADM switch 31, the number of connections of the optical transceiver and other ROADM switches may be limited, and the degree of freedom in route selection may be limited.

  A plurality of optical transceivers may be connected to one input / output port of the ROADM switch. For example, in the case of FIG. 1, a plurality of optical transceivers 57 and 58 are connected to the input / output port 206 of the ROADM switch 32 via the wavelength multiplexer / demultiplexer 41. The wavelength multiplexer / demultiplexer 41 multiplexes the optical signals of different wavelengths output from the plurality of optical transceivers 57 and 58 and outputs the optical signals to the input / output port 206 of the ROADM switch 32, and the ROADM switch. The wavelength demultiplexer 43 is configured to demultiplex an optical signal output from the 32 input / output ports 206 into wavelength components and output the demultiplexed optical signals to a plurality of optical transceivers 57 and 58.

  FIG. 2 is an internal block diagram showing the function of the ROADM switch 31. In FIG. 2, parts corresponding to those in FIG. 1 are denoted by the same reference numerals. The configuration of the input / output ports 203 and 204 is the same as that of the input / output ports 202 and 205. Therefore, the input / output ports 203 and 204 are omitted in FIG. The input / output ports 201, 202, and 205 of the ROADM switch 31 are composed of input ports 101, 103, and 109 and output ports 102, 104, and 110, respectively.

  The ROADM switch 31 includes a wavelength demultiplexer 71 that demultiplexes an optical signal input from the input port 103 into wavelength components, an optical attenuator 73 that individually attenuates the demultiplexed wavelength components, and an attenuated wavelength component. An optical switch 74 that switches the output destination to any one of all output ports 102, 104, and 110 of the ROADM switch 31, and a wavelength multiplexer 72 that wavelength-multiplexes an optical signal output to the output port 104 via the optical switch 74. And have.

  The other input ports 101 and 109 are also connected to the optical switch 74 through functional blocks equivalent to the wavelength demultiplexer 71 and the optical attenuator 73 described above. The other output ports 102 and 110 are also connected to the optical switch 74 through functional blocks equivalent to the wavelength multiplexer 72 described above.

  Each attenuation amount in the optical attenuator 73 and switching of the optical switch 74 are controlled by a ROADM control unit 91 connected to the ROADM switch 31. With this configuration, connections between all input ports 101, 103, and 109 and all output ports 102, 104, and 110 are arbitrarily selected for each wavelength, and transmission, insertion, and branching of optical signals are performed at node 1 shown in FIG. Is possible. In the actual ROADM switch 31, an optical amplifier for compensating for the loss in the optical transmission line and the ROADM switch is appropriately inserted. In FIG. 2, drawing of the optical amplifier is omitted to avoid complication.

  The function of the ROADM switch 31 shown in FIG. 2 is equivalent to a many-to-many wavelength selective switch (WSS) having a plurality of input / output ports, and can be easily constructed using a many-to-many WSS. Can do. However, many-to-many WSS has a complicated structure. For this reason, a ROADM switch composed of a small-scale WSS and an optical coupler may be used. An example of this ROADM switch is shown in FIG. In FIG. 3, parts corresponding to those in FIGS. 1 and 2 are denoted by the same reference numerals.

  The ROADM switch 31 shown in FIG. 3 includes a many-to-one WSS 82 connected to the upstream optical transmission line 11 and a one-to-many optical coupler 83 connected to the downstream optical transmission line 12. The many-to-one WSS 82 adjusts the intensity of the optical signal input from the input ports 103 and 109 for each wavelength, and multiplexes arbitrary wavelength components of all the optical signals input from the input ports 103 and 109. And output to the upstream optical transmission line 11 via the output port 102.

  The one-to-many optical coupler 83 branches the optical signal input from the downstream optical transmission line 12 via the input port 101 and outputs the branched optical signal to the output ports 104 and 110. In the configuration of the ROADM switch 31 shown in FIG. 3, the paths between some input / output ports are omitted compared to the configuration of the ROADM switch 31 shown in FIG. 2. For example, there is no path between the input port 101 and the output port 102 and between the input port 103 and the output ports 104 and 110, and the switch configuration is simplified accordingly.

  By the way, in a general ROADM system, up to nearly 100 optical transceivers are connected to one ROADM switch. However, the connection work is performed manually by the operator. Specifically, the operator connects one optical transceiver to the ROADM switch one by one. For this reason, an incorrect optical transceiver may be connected to the ROADM switch.

  For example, if an input / output port of a ROADM switch has a wavelength that is not coupled to any other input / output port, even if an optical transmitter / receiver of that wavelength is mistakenly connected to the input / output port, the signal does not conduct. This connection is referred to as “wavelength misconnection” in this specification. Also, for example, when there are two optical transceivers of the same wavelength connected to different ROADM switches in one node, each optical transceiver can obtain an expected communication destination even if they are connected alternately. I can't. This connection is referred to as “ROADM switch misconnection” in this specification.

  In the ROADM system, in order to prevent these erroneous connections, it is important to understand the connection relationship between the optical transceiver and the ROADM switch.

JP 2006-74098 A JP 2009-31778 A

  A technique for solving wavelength misconnection is disclosed in Patent Document 1. Patent Document 1 discloses a method of detecting wavelength misconnection in an arrayed waveguide grating (AWG) for wavelength multiplexing. Specifically, a configuration is shown in which an optical monitor is inserted into all input ports of an AWG, an optical wavelength monitor is inserted into an output port, and a wavelength misconnection is detected by comparing the presence or absence of input / output. This method utilizes the fact that even if an optical signal having an incorrect wavelength is input to the AWG, the optical signal is not output from the AWG.

  By applying this method, it is possible to detect erroneous wavelength connection even in the ROADM switch. Specifically, a function of setting arbitrary wavelength selectivity to each input / output port of the ROADM switch is used. For example, if the passing wavelength of the input / output port connecting the optical transceiver is set to one wavelength, and the wavelength of the passed optical signal is detected by the wavelength monitor, the wavelength misconnection can be detected as in the case of AWG. . When a plurality of optical transceivers are bundled together through an optical coupler or AWG and connected to a ROADM switch, a wavelength monitor may be inserted into an input / output port to which the optical transceiver is connected.

  However, this method cannot distinguish a plurality of optical transceivers connected to one input / output port on the ROADM switch side. For this reason, it is difficult to specify the optical transceiver having the wavelength misconnection. In particular, it is difficult to detect misconnection of optical transceivers that use the same wavelength.

  In order to solve this problem, Patent Document 2 discloses a method for identifying an optical transmission device connected to an optical cross-connect device in an optical transmission system in which an optical cross-connect device is inserted between a router and the optical transmission device. The method includes an optical power monitor inserted in the input port of the optical cross-connect device, including the identification information of the optical transmission device in the on / off pattern of the optical signal transmitted from the optical transmitter of the optical transmission device to the optical cross-connect device. By receiving this optical signal, the optical transmission device connected to the optical cross-connect device can be identified.

  When this method is applied to a ROADM system, the optical power transmitted from the optical transmitter / receiver to the ROADM switch is included in the on / off pattern of the optical transmitter / receiver and the optical signal is inserted into the input port of the ROADM switch. A configuration for receiving by a monitor is adopted. With this configuration, the optical transceiver to which the ROADM switch is connected can be individually identified.

  However, in this case, an enormous number of existing optical transceivers must be identified, and many identification patterns are required. For example, when it is necessary to identify 100,000 optical transceivers, an identification pattern of 17 bits or more is required. In addition, a normal optical power monitor cannot disassemble and observe a wavelength multiplexed signal for each wavelength component. For this reason, when a wavelength multiplexed signal is input to the input port of the ROADM switch, it is necessary to inspect the optical transceivers one by one by properly linking the optical transceiver and the optical power monitor. Therefore, there remains a problem that it takes time to identify all the optical transceiver connections. For example, if the total number of managed optical transceivers is 100,000, the maximum number of wavelengths is 100 waves, and the on / off period of the optical signal based on the identification pattern is 20 milliseconds, the time required for identification is 30 seconds or more.

  The inventor diligently studied the technical problem, and as a result, in the ROADM system, came to invent an optical transmission apparatus capable of instantaneously inspecting the connection relationship between the optical transceiver and the ROADM switch.

  The optical transmission device according to the present invention modulates an arbitrary wavelength component of an optical signal input from an input port of an arbitrary input / output port with an identification pattern that can identify the input / output port, and modulates the optical signal. A ROADM switch having a function of returning the light as a return light to the output port of the input / output port, and an optical transceiver for detecting an identification pattern of the return light received from the input / output port are arranged.

  According to the present invention, the connection relationship between the optical transceiver and the ROADM switch can be inspected. Moreover, the present invention can identify wavelength multiplexed signals simultaneously and collectively. For this reason, the connection relationship can be inspected instantaneously. For example, even when the total number of managed optical transceivers is 100,000, the maximum number of wavelengths is 100 waves, the maximum number of ROADM switches in the node is 9, and the modulation period of the optical signal by the input / output port identification pattern is 20 milliseconds, According to the present invention, the time required for identification can be suppressed to 100 milliseconds or less. Problems, configurations, and effects other than those described above will be clarified by the following description of embodiments.

The figure which shows the structure of the optical transmission apparatus which constructs | assembles a node (conventional example). The figure which shows the functional block structure of a ROADM switch (conventional example). The figure which shows the functional block structure of a ROADM switch (conventional example). The figure which shows the 1st example of an optical transmission apparatus concerning this invention. The figure which shows the example of a connection management screen which the management system in the optical transmission apparatus which concerns on this invention displays. The figure which shows the 2nd example of an optical transmission apparatus concerning this invention. The figure which shows the 3rd example of an optical transmission apparatus concerning this invention.

  DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Exemplary embodiments of a connection inspection method for an optical transmission apparatus and a wavelength selective switch according to the present invention will be described below in detail with reference to the drawings. The embodiment of the present invention is not limited to the embodiments described later, and various modifications can be made within the scope of the technical idea.

<Example 1>
FIG. 4 shows a first embodiment in the case where the present invention is applied to an optical transmission apparatus of a ROADM transmission system. FIG. 4 shows a functional block configuration of the optical transmission apparatus. In FIG. 4, parts corresponding to those in FIG.

  The optical transmission apparatus includes a management system 96 that manages the control status of the ROADM switch, the connection status between the optical transceiver and the ROADM switch, the control status of the ROADM switch, and the operating wavelength information. The management system 96 may have a function for displaying management information. The management information is displayed on, for example, the management system 96 or a display device connected to the system.

  As a management screen displayed by the management system 96, an example of a management screen in a network in which nodes A, B, and C are connected in series is shown in FIG. The management screen of FIG. 5 shows the control status of the ROADM switch and the connection status between the optical transceiver and the ROADM switch. If there is a wavelength misconnection or ROADM switch misconnection, an alarm is displayed. There are two types of alarms, “!” And “!!”, which correspond to incorrect wavelength connection and ROADM switch error connection, respectively.

  The optical transceivers 51 and 54 and the ROADM switches 32 and 33 are connected to the optical transmission line pair 21 including the pair of optical transmission lines 11 and 12 via the ROADM switch 31. The upstream optical transmission line 11 is provided with an optical wavelength monitor 92 for observing the wavelength component of the optical signal. The optical wavelength monitor 92 specifies a wavelength channel that is not in operation based on the presence / absence of a wavelength component included in the optical signal.

  A many-to-many WSS is used for the ROADM switch 31. The ROADM switch 31 includes input / output ports 101 and 102 to which optical transmission lines 12 and 11 are connected, input / output ports 103 to 106 to which optical transceivers are connected, and input / output to which other ROADM switches 32 and 33 are connected. The coupling between the input / output ports is switched between the ports 107 to 110 in units of wavelengths. Also, depending on the type of WSS, for example, if WOS of LCOS (Liquid Crystal On Silicon) is used, the optical power can be adjusted in units of wavelengths. The switching of these input / output ports and the adjustment of the optical power are controlled by the ROADM control unit 91.

  The ROADM control unit 91 has a function of extracting a wavelength channel that is not in operation from the optical signals input from all the input ports 103 and 105 to which the optical transceiver is connected, and the ROADM switch 31 and the input / output ports 103 and 104. And the function of controlling the ROADM switch 31 so that these optical signals are modulated on and off based on the identification information of 105 and 106 and turned back to the output ports 104 and 106 paired with the optical signals. The ROADM control unit 91 refers to the wavelength channel information that is not in operation from the optical wavelength monitor 92 or the management system 96 described above. When the optical signal uses an intensity modulation method for data modulation, the above-described on / off modulation is desirably sufficiently lower than the data transmission rate in order to distinguish it from data modulation.

  The optical transceivers 51 and 54 connected to the ROADM switch 31 include optical transmitters 52 and 55 that transmit optical signals, optical receivers 53 and 56 that receive optical signals, and connection detection units 61 and 62. The connection detectors 61 and 62 detect on / off modulation components of the received optical signal from the LOS (signal loss) information observed by the optical receivers 53 and 56, and the ROADM switch 31 to which the optical transceivers 51 and 54 are connected. And its input / output ports 103, 104, 105 and 106. The identified connection information is collected in the management system 96 and displayed on a display device such as a monitor. Alternatively, a display unit may be provided in each optical transceiver, and an alarm based on the identified connection information may be displayed on the display unit.

  By mounting this optical signal loopback function, the connection detectors 61 and 62 can immediately identify the connected ROADM switch and its input / output port when the optical transceiver is connected. For example, when an optical transceiver having a non-operation wavelength is connected, the connection detectors 61 and 62 can identify the connection destination input / output port from the optical signal returned by the ROADM switch.

  When the wavelength of the optical transceiver 54 is erroneously set to the same wavelength as that of the optical transceiver 51, the input / output port 203 of the ROADM switch 31 blocks the wavelength as the operating wavelength. For this reason, the optical signal input from the optical transmitter 55 of the optical transmitter / receiver 54 to the ROADM switch 31 is not returned to the input / output port 203. For this reason, the connection detection parts 61 and 62 can detect a misconnection.

  In addition, when the wavelength of the optical transceiver 58 is erroneously set to the same wavelength as that of the optical transceiver 57, the optical signal of the optical transceiver 58 is blocked by the wavelength selectivity of the wavelength multiplexer / demultiplexer 41, and the optical signal is folded back. Absent. For this reason, the connection detection part of the optical transmitter-receiver 58 can detect a misconnection.

  Even when an optical coupler having no wavelength selectivity is used as the wavelength multiplexer / demultiplexer 41, it is possible to detect an erroneous connection due to the same wavelengths of the optical transceivers 57 and 58. When the wavelength multiplexer 42 is an optical coupler, if the wavelength of the optical transceiver 58 is erroneously the same as that of the optical transceiver 57, the optical signals of the optical transceivers 57 and 58 are input to the ROADM switch 32 while interfering with each other. The Therefore, both the optical transceivers 57 and 58 return the interference light whose light intensity fluctuates. In this case, the optical transceivers 57 and 58 cannot demodulate the identification information of the ROADM switch and each input / output port from the reflected interference light. For this reason, it can be detected that there is a connection problem.

  The wavelength channel operation determination by the optical wavelength monitor 92 may be determined, for example, by whether or not the average value of the optical power in a longer time than the on / off pattern of the optical signal for connection detection does not fall below a certain threshold value. it can.

  In the description of the present embodiment, a many-to-many WSS is used for the ROADM switch 31. However, embodiments of the present invention are not limited to many-to-many WSS. For example, even when a many-to-one WSS and a one-to-many WSS are used in combination, a function equivalent to the many-to-many can be obtained. For the on / off modulation of the optical signal for connection detection, other modulation schemes such as modulation of phase and frequency, modulation of optical signal-to-noise ratio by on / off of noise light applied to the optical signal can be used. In this case, however, the connection detectors 61 and 62 of the optical transceivers 51 and 54 need to be replaced with a function for detecting these modulations.

  In the case where an optical wavelength multiplexed signal is not input / output to each input / output port 103 to 106 to which the optical transceiver of the ROADM switch 31 is connected (that is, only one optical transmitter / receiver is connected to each input / output port 103 to 106). When there is a restriction), the optical signal input to each of the input / output ports 103 to 106 is subjected to on / off modulation without being divided into wavelength components, and is output to the output ports 104 and 106 corresponding to 103 and 105 for each input port. If the state to be performed is the initial state of the ROADM switch 31, the determination of the operating wavelength by the optical wavelength monitor 92 described above becomes unnecessary.

<Example 2>
FIG. 6 shows a second embodiment when the present invention is applied to an optical transmission apparatus of a ROADM transmission system. FIG. 6 illustrates a functional block configuration of the optical transmission apparatus. In FIG. 6, parts corresponding to those in FIGS. 1 and 4 are denoted by the same reference numerals.

  The optical transmission apparatus according to this embodiment has a configuration in which the function of the ROADM switch 31 according to the first embodiment shown in FIG. 4 is expanded. The optical transmission apparatus shown in FIG. 6 includes not only input / output ports 103 to 106 that connect optical transceivers but also input / output ports 107 to 110 that connect other ROADM switches 32 and 33 to input ports 107 and 109. A non-operating wavelength channel specified using the optical wavelength monitor 92 can be extracted from the input optical signal.

  That is, the optical transmission apparatus shown in FIG. 6 performs on / off modulation of these optical signals based on the identification information of the ROADM switch 31 and the input / output ports 107, 108, 109, and 110, and returns them to the output ports 108 and 110, respectively. The ROADM switch 31 is controlled as follows. By using this configuration of the ROADM switch 31 for the other ROADM switches 32 and 33, the optical transceivers 51 and 54 connected to the ROADM switch 31 pass through the ROADM switch 31 and another ROADM switch (for example, the ROADM switch 32), and the ROADM When connected to the optical transmission lines 13 and 14 connected to the switch (for example, the ROADM switch 32), the connection between the ROADM switch 31 and the ROADM switch (for example, the ROADM switch 32) can be detected sequentially.

  In this embodiment, as described above, the non-operation wavelength is determined using the optical wavelength monitor 92. However, the optical wavelength monitor 92 is also provided with the output ports 108 and 110 to the other ROADM switches. The operating wavelength may be determined together with the information. In this case, the wavelength operated via the other ROADM switches 32 and 33 can be excluded from the non-operating wavelength as the operating wavelength.

  With this configuration, it is possible to immediately identify the connection destination ROADM switch and its input / output port when the optical transceiver is connected. The operation is the same as in the first embodiment.

<Example 3>
FIG. 7 shows a third embodiment in the case where the present invention is applied to the optical transmission apparatus of the ROADM transmission system. FIG. 7 shows a functional block configuration of the optical transmission apparatus. 7, parts corresponding to those in FIGS. 1, 3, and 4 are denoted by the same reference numerals.

  The optical transmission apparatus according to the present embodiment replaces the ROADM switch 31 according to the first and second embodiments with the ROADM switch 31 including the many-to-one WSS 82 and the one-to-many optical coupler 83 shown in FIG. It has a replaced configuration. FIG. 7 shows a configuration example of the ROADM switch 31 according to this embodiment.

  The many-to-one WSS 82 described above adjusts the optical intensity of the optical signal input from the input ports 103 and 109 of the ROADM switch 31 for each wavelength, and outputs it from the output port 102 to the upstream optical transmission line 11. In addition, a one-to-many optical coupler 83 branches an optical signal input from the downstream optical transmission line 12 to the input port 101 of the ROADM switch 31 and outputs it from the output ports 104 and 110 of the ROADM switch 31.

  The optical wavelength monitor 92 extracts the optical signal output from the output port 102 of the ROADM switch 31, monitors the wavelength component of the optical signal, and determines the non-operation wavelength. A branching optical coupler 93 is inserted between the many-to-one WSS 82 and the output port 102, and a coupling optical coupler 94 is inserted between the input port 101 and the one-to-many optical coupler 83. In the branching optical coupler 93, the optical signal output from the output port 102 is branched. The branched optical signal passes through the optical variable wavelength filter 95 and is combined with the optical signal input from the input port 101 in the coupling optical coupler 94. The combined optical signals are folded back to the output ports 104 and 110 via the one-to-many optical coupler 83.

  The optical variable wavelength filter 95 is used to limit the wavelength component of the returning optical signal to the non-operating wavelength so that the returning optical signal does not interfere with the operating wavelength. The many-to-one WSS 82 uses the identification information of the input / output ports 202 and 205 including the ROADM switch 31, the input ports 103 and 109, and the output ports 104 and 110 as non-operating wavelength channels for all input optical signals. On-off modulation.

  With this configuration, the optical signal of the optical transceiver is returned by the ROADM switch, and the connection with the ROADM switch is immediately detected. However, in this configuration, there is a possibility that an optical signal including a non-operation wavelength propagates from the downstream optical transmission line 12.

  As a countermeasure, there is a method in which node information is included in identification information placed on an optical signal by on-off modulation of a many-to-one WSS 82. In this case, the connection detector of the optical transceiver determines whether the optical signal received from the detected identification information is an optical signal transmitted from an external node, and uses the optical signal transmitted from the external node. If there is, the result of the connection detection is invalidated, and transmission of the optical signal from the optical transceiver is temporarily suspended.

  As another countermeasure, there is a method of placing identification information of the optical transceiver on the optical signal transmitted by the optical transceiver. In this case, when the connection detector of the optical transceiver detects this identification information and the received optical signal is not an optical signal transmitted from the optical transceiver, the result of the connection detection is invalidated, and the optical The transmission of the optical signal from the transceiver is interrupted.

  If the identification information of the optical transceiver is transmitted by high-speed data modulation, it is possible to avoid an increase in the identification time of the connection relationship between the optical transceiver and the ROADM switch.

  In this embodiment, both the many-to-one WSS 82 and the one-to-many optical coupler 83 may be WSS. Further, the WSS and the optical coupler may be reversely arranged. However, when the WSS and the optical coupler are reversed, the optical signal received by the optical transceiver is transmitted from the external node even if the identification information including the node information is placed on the optical signal by the on-off modulation of the many-to-one WSS. It is not possible to determine whether it is an optical signal. Therefore, in order to discriminate an optical signal transmitted from an external node, it is necessary to use a method in which identification information of the optical transceiver is placed on the optical signal transmitted by the optical transceiver.

  By the way, also in all other embodiments, the optical transmitter / receiver puts identification information of the optical transmitter / receiver on the optical signal transmitted from the optical transmitter, and the optical signal received by the optical receiver of the optical transmitter / receiver A method for inspecting that the optical signal is transmitted from the optical transceiver can be used. In addition, since this method makes it possible to identify the transmission source of the received optical signal, it becomes possible to detect when the input / output port is erroneously connected between the optical transceivers, and the optical transceiver and the ROADM switch can be detected. This also has the effect of making the detection of erroneous connection more reliable.

<Other forms>
The present invention is not limited to the above-described embodiments, and includes various modifications. For example, the above-described embodiments have been described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the configurations described. Moreover, it is possible to replace a part of a certain form example with the structure of another form example, and it is also possible to add the structure of another form example to the structure of a certain form example. Moreover, it is also possible to add, delete, or replace another structure with respect to a part of structure of each form example. Moreover, you may implement | achieve some or all of each structure, a function, a process part, a process means, etc. which were mentioned above as an integrated circuit or other hardware, for example.

DESCRIPTION OF SYMBOLS 1 ... Node 11, 13, 15 ... Upstream optical transmission path 12, 14, 16 ... Downstream optical transmission path 21, 22, 23 ... Optical transmission path pair 31, 32, 33 ... ROADM switch 41 ... Wavelength multiplexer / demultiplexer DESCRIPTION OF SYMBOLS 42 ... Wavelength multiplexer 43 ... Wavelength demultiplexer 51, 54, 57, 58 ... Optical transmitter / receiver 52, 55 ... Optical transmitter 53, 56 ... Optical receiver 61, 62 ... Connection detection part 71 ... Wavelength multiplexer 72 ... Wavelength demultiplexer 73 ... Optical attenuator 74 ... Optical switch 81 ... Optical folding section 82 ... Many-to-one WSS
DESCRIPTION OF SYMBOLS 83 ... One-to-multiple optical coupler 91 ... ROADM control part 92 ... Optical wavelength monitor 93 ... Optical coupler for branching 94 ... Optical coupler for coupling 95 ... Optical variable wavelength filter 96 ... Management system 101, 103, 105, 107, 109 ... Input Ports 102, 104, 106, 108, 110 ... Output ports 201, 202, 203, 204, 205, 206 ... Input / output ports

Claims (12)

A plurality of input / output ports, an optical modulator that modulates an arbitrary wavelength component of an optical signal input from an input port of an arbitrary input / output port according to an identification pattern of the input / output port, and modulation by the optical modulator A ROADM switch having an optical return unit that returns the optical signal as a return light to the input port and a pair of output ports;
An optical transmitter for transmitting the optical signal to the input / output port; an optical receiver for receiving the return light; and a connection for detecting the identification pattern by detecting a modulation component by the optical modulator from the return light. An optical transmission device comprising: an optical transceiver having a detection unit. The optical transmission device according to claim 1,
An optical transmission device comprising: a display device that displays a connection state of each transceiver. The optical transmission device according to claim 1,
The optical transmitter / receiver includes a display unit that displays information based on a connection state of the optical transmitter / receiver. The optical transmission device according to claim 1,
Light that decomposes and observes an optical signal output from an output port of the ROADM switch connected to an optical transmission line and / or another ROADM switch into wavelength components, and discriminates a wavelength that is not observed at all for a certain period of time as a non-operating wavelength An optical transmission device comprising a wavelength monitor, wherein only the non-operational wavelength is turned back at the light turn-back section. The optical transmission device according to claim 1,
The optical modulator is an optical attenuator, and the modulation is intensity modulation. The optical transmission device according to claim 5,
The optical transmission apparatus, wherein the intensity modulation is on / off modulation, and the connection detection unit detects the identification pattern from signal loss information detected by the optical receiver. The optical transmission device according to claim 1,
An optical wavelength monitor for decomposing and observing the output to the upstream optical transmission line into wavelength components;
And a management system that discriminates a wavelength that is not observed at all for a certain period of time in the optical wavelength monitor as a non-operational wavelength. The optical transmission device according to claim 1,
The light folding portion is
An optical branching unit for branching the output to the upstream optical transmission line;
One of the outputs branched by the optical branching unit is input, and a filter unit that cuts out only the non-operating wavelength by the optical wavelength tunable filter,
An optical transmission device comprising: an optical coupling unit that couples the non-operational wavelength cut out by the filter unit to a downstream optical transmission line. The optical transmission device according to claim 8,
A first wavelength selective switch connected to the upstream optical transmission line;
An optical transmission device comprising: a second wavelength selective switch connected to the downstream optical transmission line. The optical transmission device according to claim 8,
One of the first wavelength selective switch connected to the upstream optical transmission path and the second wavelength selective switch connected to the downstream optical transmission path is replaced with an optical coupler. An optical transmission device. The optical transmission device according to claim 8,
The input / output port identification pattern includes a node in which a ROADM switch is installed or an identifier of the ROADM switch,
The optical transmission apparatus, wherein the connection detection unit of the optical transmitter / receiver extinguishes an optical signal transmitted by the optical transmitter / receiver while an identification pattern indicating another node or the ROADM switch is detected. The optical transmission device according to claim 1,
The optical transmitter of the optical transceiver outputs identification information of the optical transceiver on an optical signal, and the optical receiver of the optical transceiver transmits the optical transceiver on the received optical signal. If the received optical signal is an optical signal transmitted from the optical transmitter in the same optical transceiver as the optical receiver, the connection detection unit is used to connect the ROADM switch to the ROADM switch. An optical transmission device that detects a connection state and issues an alarm if the received optical signal is not an optical signal transmitted from the optical transmitter.

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