JP2005080108A - Optical repeater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make communication between nodes possible when at least either of optical transmission paths between node and a repeater or between the repeaters is normal by terminating two pairs of the optical transmission paths at a repeater level in an optical repeater connected with redundant optical transmission paths such as a duplex operation between nodes. <P>SOLUTION: This optical repeater is provided with redundant input terminal and output terminal, a phase adjustment part which multiplexes phases of inputted signal light beams to each input terminal by mutually adjusting them, an optical amplifier which amplifies outputted signal light from the phase adjustment part to a predetermined level and a branching part which branches the outputted signal light of the optical amplifier to each output terminal. The optical repeater is constituted by providing a plurality of optical repeaters and providing an optical switch which switches the inputted signal light beams of each optical repeater based on a control signal. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an optical repeater, and more particularly to an optical repeater installed on an optical transmission line between nodes such as an exchange and a router in a communication network realizing an APS (Automatic Path Switching) service.

  In recent years, high-speed communication using optical fiber transmission lines has become possible along with the demand for higher-speed communication infrastructure, and in order to meet the demands for communication reliability, the optical transmission line is duplicated between nodes and is automatically used when a single-side failure occurs. Service that switches and continues operation (so-called ASP pair service) has been introduced. At this time, when the transmission distance from the subscriber accommodation node to the relay node is long, it is common practice to install optical repeaters at certain distances between the nodes.

  When multiple optical repeaters are installed, if a failure occurs in the transmission path between the node and the optical repeater, or between the optical repeaters, a failure occurs in the transmission line failure between the nodes in the APS pair. Will cause the APS service to stop working.

  The reason for this is that conventional optical repeaters usually have only the function of once terminating and regenerating the signal on the transmission side, and the light of the APS pair between the node and the optical repeater or between the optical repeaters. When one of the transmission lines fails, the failure state is merely relayed to the opposite node or optical repeater side.

  This is illustrated in Fig. 1 (2). Nodes 1000-1001 are connected by a duplex optical transmission line (APS pair P1) consisting of a working optical transmission line L1 and a standby optical transmission line L2, and one optical transmission line is transmitted. The optical repeaters 100a and 101a are installed on the path L1, and the optical repeaters 100b and 101b are installed on the standby optical transmission line light L2.

  In such a configuration, as shown in the figure, a failure T1 occurs in the optical transmission line light L2 between the node 1000 and the optical repeater 100b, and in the optical transmission line L1 between the optical repeaters 100a and 101a. When the failure T2 occurs, the nodes 1000 and 1001 both recognize that the failure is in both systems of the duplexed optical transmission line. That is, for example, only when the optical transmission lines L1 and L2 across the optical repeaters 100a and 100b are not in a failure state, the facing nodes can recognize the state, that is, execute the APS service autonomously. It will be possible.

As such a conventional technique, in a parallel operation system of a TV relay broadcaster constituted by a receiving system for receiving and converting an input signal and a transmitting system for transmitting and converting the signal from the receiving system, 2 system receive converters that receive and convert the signal from the local signal, and phase shift synthesizer that phase shift synthesizes and outputs each of the received and converted signals. A local oscillation synthesizer and a circulator synthesizer, and the local oscillation synthesizer synthesizes the two transmission local oscillator signals in phase-synchronization and distributes the output for local transmission of the two transmission converters. The transmission conversion unit transmits and converts the signal from the reception system by the local signal, and the circulator synthesis unit receives the signal from the transmission conversion unit by the first and second circulators, and the third circulator. It is synthesized and output with There is parallel operation system of the TV relay broadcasting machine for (e.g., see Patent Document 1).
JP-A-56-776

  As described above, in the conventional technology, there is a device that can terminate the duplex transmission line by an electric circuit. However, an optical repeater is not suitable because it requires photoelectric conversion once and the transmission speed is limited. Because the duplexer cannot terminate the duplex transmission path, there is a problem that the communication is immediately interrupted for both system failures between nodes.

  Therefore, in the present invention, in an optical repeater connected to a redundant optical transmission line such as duplex between nodes, if at least one of the input side optical transmission lines is normal without performing photoelectric conversion, The purpose is to enable communication between nodes.

  In order to solve the above problems, if either one of the APS pairs on the input side of the optical repeater is normal and one of the APS pairs on the output side of the optical repeater is normal, By enabling transmission of information in the upstream direction (direction from the input side to the output side of the optical repeater), APS due to a transmission line failure between the opposing nodes on the redundant optical transmission line executing the APS service It can be seen that the probability that the pair is obstructed can be reduced.

  For this reason, the optical repeater according to the present invention includes redundant input terminals and output terminals, a phase adjustment unit that adjusts the phases of the input signal lights to each input terminal, and combines the phase adjustment units. An optical amplifier that amplifies each output signal light from the unit to a predetermined level, and a branching unit that branches the output signal light of the optical amplifier to each output terminal.

  That is, in the present invention, the phase adjustment unit adjusts the phase of the input signal light to each input terminal and combines them, and even if a failure occurs in one of the optical transmission lines, After the input signal light is amplified to a predetermined level by the optical amplifier, the output signal light of this optical amplifier is branched and output to the respective output terminals.

  This will be schematically described with reference to FIG. 1 (1). Assuming that the faults T1 and T2 have occurred as in FIG. 2 (2) showing the conventional example, in the present invention, the optical transmission line L2 Even if the failure T1 occurs, the optical repeater 1_1 of the present invention sends the input signal light from the optical transmission line L1 to the APS pair P1 of the output side optical transmission lines L1 and L2, as indicated by the dotted line. However, since the failure T2 occurs in the optical transmission line L1, the signal light is sent to the adjacent optical repeater 1_2 of the present invention only through the optical transmission line L2, and the optical repeater 1_2 Even if there is only an input signal from the optical transmission line L2 of the system, the signal light branched to the optical transmission lines L1 and L2 of both systems can be sent to the node 1001.

  As described above, in the present invention, the redundant optical transmission line can be terminated at the optical repeater level, so that even when one side failure of the APS pair transmission line occurs, the optical relay is performed to the opposite node without photoelectric conversion without interruption. Making it possible to do.

  That is, in the conventional optical repeater, for example, when a failure occurs in the operation system, a momentary interruption occurs because of switching to the standby system, but in the present invention, the phase of the redundant input signal light is adjusted and multiplexed. Further, by branching, the output side can be relieved without interruption, and the probability of a transmission path failure can be reduced as compared with the conventional example.

  The phase adjustment unit is a Mach-Zehnder interferometer, and the branching unit returns the wavelength of the output signal light from the optical amplifier to the same wavelength as the input signal light, and the wavelength conversion It is possible to provide a splitter for branching the output signal light of the device to each output terminal.

  Further, the Mach-Zehnder interferometer includes a common CW light (coherent light) light source, a redundant phase adjuster that modulates the CW light with each input signal light and performs phase adjustment, and each phase Of the input signal light wavelength component output from the adjuster and the modulated CW light wavelength component, a redundant band pass filter that passes only the CW light wavelength component and the output light of each band pass filter are branched. A redundant splitter, a multiplexer that multiplexes one output light of each splitter, and a phase difference of the other output light of each splitter are measured, and the phase adjuster is controlled so that they match each other. It can be configured by a control unit.

  In the case of the above-mentioned present invention, it is assumed that only one of the redundant optical transmission lines has a failure, and when both systems fail, the function as an optical repeater Can not demonstrate.

  Therefore, in the present invention, by further providing an optical repeater provided with a plurality of optical repeaters having the above-described configuration, and provided with an optical switch that switches input signal light of each optical repeater based on a control signal, This has been eliminated.

  In other words, in any one of the optical repeaters in the optical repeater, even if both system failures occur in the input-side all-optical transmission line, for example, by detecting this transmission line failure at the phase adjustment unit or the opposite node. Based on the generated control signal, the optical switch provided in common to each optical repeater is switched, and the subsequent optical repeater or node passes through the optical repeater appropriately combined with the input signal light. Can be sent to.

  Even if no failure has occurred, a desired combination among a plurality of combinations of APS pairs can be selected based on the control signal.

  This control signal may be given from the maintenance console to each optical switch via a control line.

  In this way, the optical transmission path failure of all input systems is also dealt with.

  As described above, according to the optical repeater according to the present invention, when a one-system failure occurs between a node and a repeater of an optical transmission line or between a repeater and a repeater, optical repeater is performed without interruption for an opposing device. It becomes possible. Furthermore, according to the optical repeater according to the present invention, it becomes possible to maintain optical repeater even when both system failures occur.

[Example (1): Optical repeater]
FIG. 2 shows an optical repeater as an embodiment (1) of the present invention, and this optical repeater 1 corresponds to the optical repeater 1_1 or 1_2 shown in FIG. 1 (1). .

In this embodiment, a Mach-Zehnder interferometer 2 is used as the phase adjusting unit, and the Mach-Zehnder interferometer 2 includes an optical amplifier 7 such as an _Er- doped optical fiber that amplifies input signal light to a predetermined level. The wavelength converter 8 and the splitter 9 that pass through the optical amplifier 7 are connected in series, and the wavelength converter 8 and the splitter 9 constitute a branching unit.

  As a redundancy example, the Mach-Zehnder interferometer 2 is provided with a series circuit of a phase adjuster 21_1, a band pass filter (BPF) 22_1, and a splitter 23_1 corresponding to the active optical transmission line L1. Further, a series circuit of a phase adjuster 21_2, a bandpass filter 22_2, and a splitter 23_2 is provided corresponding to the standby optical transmission line L2, and the splitters 23_1 and 23_2 are coupled by a multiplexer 24.

  Further, a laser diode 3 is provided in common for these phase adjusters 21_1 and 21_2, and the CW light (coherent light: wavelength λ2) M3 from the laser diode 3 passes through the splitter 4 to be the phase adjuster. 21_1 and 21_2 are provided as pump light in common, and phase adjusters 21_1 and 21_2 respectively modulate the CW light M3 from the splitter 4 with the signal light M1 and M2 of the wavelength λ1, and the input signal light component of the wavelength λ1. The CW light component having the wavelength λ2 is combined and output.

  Then, the signal light components of these two wavelengths λ1 and λ2 are extracted only by the bandpass filters 22_1 and 22_2, respectively, and transmitted to the splitters 23_1 and 23_2, respectively.

  The splitters 23_1 and 23_2 send only a part of the signal light components to the amplitude / phase measuring device 5 and send the other signal light components to the multiplexer 24 to multiplex the signal light of both systems to the optical amplifier 7 To send to.

  The signal light sent to the amplitude / phase measuring device 5 is measured for the phase difference between the two and sent to the control device 6. The control device 6 is connected to the input signal light M1 having the wavelength λ1 in the phase adjusters 21_1 and 21_2. Phase matching of the input signal light M2 having the wavelength λ1 is performed. As a result, the phases of the signal lights of both systems when combined by the multiplexer 24 are matched and amplified. As will be described later, the amplitude / phase measuring device 5 also measures the amplitude of the signal light in order to detect a failure.

  Then, the signal light combined in this way by the multiplexer 24 is subjected to predetermined optical amplification as an optical repeater in the optical amplifier 7. That is, after the signal light is optically amplified to a predetermined level required for the optical repeater operation, the wavelength converter 8 constituting the branching unit returns the signal light having the wavelength λ2 to the signal light M4 having the wavelength λ1, and also forms the branching unit. The splitter 9 splits and outputs the working signal light M5 having the wavelength λ1 and the spare signal light M6.

  In this embodiment (1), a Mach-Zehnder interferometer is used as the phase adjustment unit. However, the active and standby signal lights M1 and M2 are sent to the multiplexer 24 with the same phase. Any signal can be used as long as it can be waved. In this case, the signal light having the original wavelength λ1 can be obtained by the multiplexer 24, so that the wavelength converter 8 is not necessary.

  FIG. 3 shows an operation example of the embodiment (1) shown in FIG. 2, and in this case, shows an operation example when the signal light interruption D1 occurs in the standby optical transmission line L2. .

That is, the phase adjusters 21_1 and 21_ from the laser diode 3 via the splitter 4
Level of the CW light M3 given to 2 are both E _3/2, in this example, signal light M1 (Level E ₁₎ of the wavelength λ1 from the working optical transmission lines L1 only to the phase adjuster 21 _ that is given to become, the other phase adjuster 21_2 only CW light from the splitter 4 (level E _3/2) is applied.

Therefore, the level E ₁ (wavelength .lambda.1) from the phase adjuster 21 _ + Level E _3/2 output signal light (wavelength .lambda.2) is applied to the band-pass filter 22_1, and from the phase adjuster 21_2 level E _3/2 ( Only the output CW light of wavelength λ2) is given to the bandpass filter 22_2.

That is, in the phase adjuster 21_1, the CW light M3 from the splitter 4 is modulated by the input signal light M1 from the optical transmission line L1, and the output light from the phase adjuster 21_1 is the input signal light M1 to the CW light M3. Although would be given to the band-pass filter 22_1 is aboard the signal light, in the phase adjuster 21_2, the signal light M2 from standby optical transmission lines L2 is not, as is the level E _3/2 of the CW light M3 is given to the bandpass filter 22_2.

In the band-pass filter 22_1, passes the signal light component of the CW light M3 wavelength .lambda.2, the signal light component of the signal light component of the input signal light M1 is passed blocked, levels E _3/2 modulation of the CW light M3 There will be given to the splitter 23_1, the bandpass filter 22_2, since the CW light only level E _3/2 at a wavelength λ2 is input, it is directly fed passed to the modulation splitter 23_2.

In the splitters 23_1 and 23_2, a part of each input light is branched to the amplitude / phase measuring device 5, and the other branched output light is sent to the multiplexer 24. In this case, in the splitters 23_1 and 23_2, since the output light both levels is approximately E _3/2, the multiplexer 24 will total level is sent to the optical amplifier 7 are multiplexed to the signal light of the wavelength λ2 at E _3.

  During normal operation, part of the output light from the splitters 23_1 and 23_2 are both sent to the amplitude / phase measuring device 5, where the phase difference between them is measured, and the controller 6 adjusts the phase based on this phase difference. In this example of FIG. 3, there is no output signal light component of the splitter 23_2 (illustrated by a dotted line and X), so the splitter 21_1 and 21_2 perform mutual phase adjustment. Only the output signal light of 23_1 is sent to the amplitude / phase measuring device 5, but since no phase difference can be measured, no control signal is sent to the control device 6.

The optical amplifier 7 to which the output signal light of the level E ₃ (wavelength λ 2) is given from the multiplexer 24 performs optical amplification so as to generate a predetermined level of output signal light. That is, in this case, for example, the output signal light amplified to level 2E ₃ is given to the wavelength converter 8, and the wavelength converter 8 returns the wavelength λ2 of the input signal light to the wavelength λ1 of the input signal light M1. And give to splitter 9.

Accordingly, the splitter 9 divides the level 2E ₃ signal light (wavelength λ 1) into two parts, and branches and outputs the signal light to the working signal light M 5 and the spare signal light M 6 at level E ₃ , respectively.

  In the above embodiment, the signal light interruption D1 occurs only in the standby optical transmission line L2, but the same case can be considered when the signal light interruption occurs only in the active optical transmission line L1.

Moreover, even during normal, the band since the path output level of the filter 22_1 and 22_2 are both in E _3/2, splitters 23_1 and the signal light level of which has been multiplexed by the multiplexer 24 via 23_2 almost E _Thus , the same level of signal light as that in the case where a signal light interruption occurs in one of the optical transmission lines is given to the optical amplifier 7.
[Example (2): Optical repeater]

  In the case of the above embodiment (1), assuming that the signal light interruption occurs only in one of the optical transmission lines L1 or L2, the optical transmission lines L1 and L2 of both systems cause the signal light interruption Therefore, no signal light is output from the multiplexer 24.

  Therefore, in the case of the embodiment (2) shown in FIG. 4, the optical repeater shown in the above embodiment (1) is made redundant, and the signal light is switched between these optical repeaters 1a_1 and 1b_1 by an optical switch. By doing this, any of the APS pairs tries to cope with a case where a transmission path failure occurs.

  That is, in the optical repeater 10 shown as the embodiment (2) of the present invention, the optical repeaters 1a_1 and 1b_1 are provided with the Mach-Zehnder interferometers 2a and 2b, respectively, and the Mach-Zehnder interferometer 2a is provided with the optical amplifier 7a and A wavelength converter 8a and a splitter 9a are connected in series, and an optical amplifier 7b, a wavelength converter 8b, and a splitter 9b are connected in series to the Mach-Zehnder interferometer 2b. Also, an optical switch 11 for switching these optical transmission lines is provided between the Mach-Zehnder interferometers 2a and 2b and the duplexed optical transmission lines L1_1, L2_1 and L1_2, L2_2 corresponding to them. Yes.

  The Mach-Zehnder interferometer 2a has the same configuration as that of the Mach-Zehnder interferometer 2 shown in FIG. 3 except that the symbol “a” is attached. The configuration is the same as that of the Mach-Zehnder interferometer 2 except that the symbol “b” is attached.

  The amplitude / phase measuring device 5 receives the output light B1 from the splitters 23a_1 and 23a_2 and the output light B2 from the splitters 23b_1 and 23b_2 in the Mach-Zehnder interferometer 2b, and the phase difference between these output lights B1 and B2 And the control signal A1 is given to the phase adjusters 21a_1 and 21a_2 via the control device 6, and the control signal A2 is given to the phase adjusters 21b_1 and 21b_2.

  The amplitude / phase measuring device 5 can detect the signal light interruption state of the working system or the standby system by measuring the amplitudes of the output lights B1 and B2. That is, when a signal light interruption state occurs due to an optical transmission line failure, the signal light interruption detection can be performed assuming that there is no signal light component of the output light B1. The optical switch control device 12 receives a signal light interruption signal from the amplitude / phase measuring device 5, or receives a control signal from another device such as a node or an optical repeater, or a control signal from a maintenance console The control signal for the optical switch is received and the control signal C1 for the optical switch 11 is generated, so that the optical switch 11 can be switched.

  It should be noted that the amplitude / phase measuring device 5 does not consider the occurrence of a failure even if one system of signal light cannot be detected, and considers the occurrence of a failure only when the signal light of both systems cannot be detected.

  That is, as in the operation example shown in FIG. 5, when the signal light breaks D2 and D3 occur in both systems of the optical transmission lines L1_1 and L2_1, the amplitude / phase measuring device 5 applies the signal light B1 from the splitters 23a_1 and 23a_2. On the basis of such a transmission line failure of both systems, when the optical switch control device 12 gives the signal light break detection signal, the optical switch control device 12 is connected to the optical switch 11 by a dotted line connection path. By giving the control signal C1 to switch from the solid line to the solid connection path, as shown in the figure, the signal light from the optical transmission line L1_2 is given to the phase adjuster 21a_1 of the Mach-Zehnder interferometer 2a as shown by the solid line The signal light from the transmission line L2_2 is sent to the phase adjuster 21a_2 of the Mach-Zehnder interferometer 2a as indicated by the solid line.

  Accordingly, in the phase adjuster 21a_1, the CW light M3a from the splitter 4a is modulated by the signal light from the optical transmission line L1_2 and given to the bandpass filter 22a_1, so that only the CW light component of wavelength λ2 is in this band. The signal is sent to the multiplexer 2a via the pass filter 22a_1 and the splitter 23a_1.

  Further, in the Mach-Zehnder interferometer 2a, the signal light from the transmission line L2_2 is given to the phase adjuster 21a_2 so that the light is combined via the phase adjuster 21a_2, the bandpass filter 22a_2, and the splitter 23a_2 in the same manner as described above. The same is sent to the waver 24a.

This state is the same as the case where the signal light is given to the phase adjusters 21_1 and 21_2 in the embodiment (1) shown in FIG. 2, and the signal light (wavelength λ2) of the level E ₂ is output from the multiplexer 24a. The signal is supplied to the optical amplifier 7 and branched and output as signal lights M5_1 and M6_1 via the wavelength converter 8a and the splitter 9a.

  In this way, even when the optical transmission lines L1 and L2 are both in the signal light interruption state, the active system signal light and the standby system signal light are transmitted via the optical repeater 2a by controlling the optical switch 11. Each can be output.

In this embodiment (2), only one of the optical repeaters 1a_1 of the optical repeaters 1a_1 and 1b_1 of the optical repeater 10 is used in total of the signal lights M5_1 and M6_1 and the signal lights M5_2 and M6_2. This is to avoid the situation where four signal lights are output and the 2 × 2 optical repeater system is not complied with.
[Example (3): Optical repeater]

  In the case of the embodiment (2) shown in FIG. 5 above, the optical repeater 10 is provided with two optical repeaters 1a_1 and 1b_1 as redundancy examples, but in the case of the embodiment (3) shown in FIG. The optical repeaters 10_1 and 10_2 provided between the nodes 1000 and 1001 respectively include three optical repeaters 1a_1 to 1c_1, 1a_2 to 1c_2 and optical switches 11_1 and 11_2, and APS pairs P1 to P3, respectively. The point of being connected to is different.

In the operation example (1) of the embodiment (3) , when a failure T1 occurs in one optical transmission line of the APS pair P2 as shown in the drawing, the optical repeater 10_1 uses the APS pair P1 (optical transmission line L1_1 , L2_1) is normal, so that the optical repeater 1a_1 performs multiplexing and demultiplexing G of the signal light of both systems via the optical switch 11_1 and outputs it, and outputs the APS pair P2 (optical transmission line L1_2, Since the optical repeater for L2_2) has a failure in one optical transmission line, it performs multiplexing and demultiplexing G on the signal light in the other normal optical transmission line and outputs it, and further the APS pair P3 Since (optical transmission lines L1_3, L2_3) are normal in both systems in the same manner as the APS pair P1, signal light is output by performing multiplexing / demultiplexing G on the signal light in both systems.

  As shown in the figure, in the APS pair P1, when the failure T2 occurs between the optical repeaters 10_1 and 10_2, the signal light output from the optical repeater 1a_1 by the combined demultiplexing G is the light In the optical repeater 1a_2 in the repeater 10_2, it is output by the combined demultiplexing G by the signal light of one system and sent to the node 1001.

  Since the other optical transmission lines are normal, in the optical repeater 10_1, the signal light output from the optical repeater 1b_1 by the combined demultiplexing G by the single-system signal light and the combined light by the signal light of both systems The signal light output from the optical repeater 1c_1 by the wave G is output to the node 1001 by the optical repeater 1b_2 and 1c_2 performing the combined demultiplexing G based on both normal signal lights in the optical repeater 10_2. ing.

In the case of the operation example (2) of the embodiment (3) shown in FIG. 7, it is first assumed that the APS pair P2 has both failed T1 and T2 between the node 1000 and the optical repeater 10_1. . In this case, in the optical repeater 10_1, both signal light in the APS pair P1 and signal light in both systems in the APS pair P3 are both normal, so the optical repeaters 1a_1 and 1c_1 receive the combined demultiplexing G and output However, in the APS pair P2, the optical repeater 1b_1 detects the light interruption of the input signals of both systems.

  This is detected by the amplitude / phase measuring device 5 as shown in FIG. 5 (step S1). Then, when detecting the two-system input signal light disconnection in this way, in the optical repeater 10_1, the two-system input disconnect signal (1) and the maintenance interface (control line) IF from the optical switch control device 12 (2) is notified to the node 1000, the optical repeater 10_2, and the node 1001 (step S2).

  Upon receiving this notification (1), the node 1000 can recognize from the node 1000 that the optical repeater before 10_1 is a transmission line failure (step S3), and the node 1001 can recognize the optical repeater after 10_2 as a transmission line failure. (Step S4).

  In the case of the operation example (2) in FIG. 7, it goes without saying that all the APS pairs P1 to P3 can be effectively switched and connected by controlling the optical switch 11_1 as in FIG.

In the case of the operation example (3) of the embodiment (3) shown in FIG. 8, in the same system configuration example as in FIG. 7, when the failures T1 and T2 occur similarly in the optical transmission lines L1_2 and L2_2, respectively. The optical repeater 10_1 can also receive the control signal (1) from the node 1000. In this case, the optical switch 11_1 is subjected to switching control via the optical switch controller 12_1 as shown in the figure.

  That is, the signal light from the optical transmission line L1_1 is given to the optical repeater 1a_1 through the optical switch 11_1, and is output by the multiplexing / demultiplexing G of the single-system signal light. The signal light from the optical transmission line L2_1 is switched and input as one signal light of the optical repeater 1b_1 corresponding to the failed optical transmission lines L1_2 and L2_2 via the optical switch 11_1. As the other input signal light of the optical repeater 1b_1, the signal light from the optical transmission line L1_3 is given and output from the optical repeater 1b_1 by the combined demultiplexing G of the signal lights of both systems.

  Further, the signal light from the optical transmission line L2_3 is input to the corresponding optical repeater 1c_1, and the signal light is output to both of the optical transmission lines L1_3 and L2_3 by the single-system signal optical multiplexing / demultiplexing G.

  When a failure T3 occurs in the optical transmission line L1_1 between the optical repeaters 10_1 and 10_2, only one of the output signal lights multiplexed / demultiplexed G by the optical repeater 1a_1 is transmitted to the optical repeater 10_2. Then, the optical repeater 1a_2 receives the one-system signal light multiplexing / demultiplexing G via the optical switch 11_2 and outputs it to the node 1001.

  The other output signal light from the optical repeater 10_1 is normally sent to the optical repeater 10_2, and is received by the optical repeaters 1b_2 and 1c_2, receiving the signal optical multiplexing / demultiplexing G of both systems, and output to the node 1001. Become.

  The same effect can be obtained by controlling the optical switch 11_1 or 11_2 using the control signals (2) to (4) from the maintenance console MC in addition to the control signal (1) from the node 1000 as described above. It is done.

In the operation example (4) of the embodiment (3) shown in FIG. 9, there is no failure between the node 1000 and the optical repeater 10_1, but the optical transmission from the optical repeater 1b_1 to the optical repeater 1b_2 It is assumed that both roads L1_2 and L2_2 have faults T1 and T2. In this case, both systems input disconnection is detected in the optical repeater 1b_2 in the optical repeater 10_2 (step S11), and both systems input disconnection is notified from the optical switch controller 12_2 accordingly (step S12). .

  As a result, when the control signal (1) is sent to another relay apparatus or node, the node 1000 recognizes that the optical relay apparatus 10_1 before the node 1000 is a transmission path failure (step S13), and the node 1001 In step S14, it is possible to recognize that the optical repeater 10_1 and later have a transmission path failure (step S14). When such a system failure between repeaters occurs, switching between APS pairs on the node side cannot be avoided or transmission path resources cannot be used effectively. Switching will be performed.

  That is, the optical switch 11_1 of the optical repeater 10_1 receives a switching instruction from the node 1000 or the maintenance console MC via the optical switch control device 12_1 (step S15), and the APS pair P2 related to the failure is transferred to the spare optical repeater 1d_1. Switch to guide.

  At the same time, the optical switch 11_2 of the optical repeater 10_2 also receives a switching instruction from the node 1000 or the maintenance console MC via the optical switch controller 12_2 (step S16), and the input signal light from the optical repeater 1d_1 of the optical repeater 10_1 Is switched to the optical repeater 1b_2 corresponding to the original APS pair P2.

  The notification of disconnection of both systems (step S12) may be a control signal (2) sent to the maintenance console MC or a control signal (3) sent to the node 1001.

(Appendix 1)
Redundant input and output terminals;
A phase adjustment unit that mutually adjusts and combines the phases of the input signal light to each input terminal;
An optical amplifier that amplifies the output signal light from the phase adjustment unit to a predetermined level;
A branching section for branching the output signal light of the optical amplifier to each output terminal;
An optical repeater comprising:

(Appendix 2) In Appendix 1 above,
The phase adjustment unit is a Mach-Zehnder interferometer, and the branching unit returns the wavelength of the output signal light from the optical amplifier to the same wavelength as the input signal light, and the output of the wavelength converter An optical repeater comprising a splitter for branching signal light to each output terminal.

(Appendix 3) In 2 above,
The Mach-Zehnder interferometer includes a common CW light source, a redundant phase adjuster that modulates the CW light with each input signal light and performs phase adjustment, and an input output from each phase adjuster Of the signal light wavelength component and the modulated CW light wavelength component, a redundant bandpass filter that passes only the CW light wavelength component, and a redundant splitter that branches the output light of each bandpass filter, A multiplexer that multiplexes one output light of each splitter, and a control unit that controls the phase adjuster so as to match each other by measuring the phase difference of the other output light of each splitter An optical repeater characterized by

    (Appendix 4) A plurality of optical repeaters according to any one of Appendices 1 to 3 above are provided, and an optical switch that switches input signal light of each optical repeater based on a control signal is provided. An optical repeater.

(Appendix 5) In Appendix 4 above,
The optical repeater is characterized in that the control signal is given to each optical switch via the control line from the phase adjusting unit or the opposite node that detects the transmission path failure.

(Appendix 6) In Appendix 4 above,
An optical repeater characterized in that the control signal is given from the maintenance console to the optical switch of each optical repeater via a control line.

It is the block diagram which compared this invention and the prior art. FIG. 3 is a block diagram showing a configuration example of an optical repeater as an embodiment (1) of the present invention. FIG. 3 is a block diagram showing an operation example of FIG. FIG. 5 is a block diagram showing a configuration example of an optical repeater as an embodiment (2) of the present invention. FIG. 5 is a block diagram illustrating an operation example of FIG. FIG. 7 is a block diagram showing an operation example (1) of an optical repeater including three optical repeaters as an embodiment (3) of the present invention. FIG. 6 is a block diagram showing an operation example (2) of an optical repeater including three optical repeaters as an embodiment (3) of the present invention. FIG. 7 is a block diagram showing an operation example (3) of an optical repeater including three optical repeaters as an embodiment (3) of the present invention. FIG. 6 is a block diagram showing an operation example (4) of an optical repeater including three optical repeaters as an embodiment (3) of the present invention.

Explanation of symbols

1,1_11_2,1a_1〜1c_1,1a_2〜1c_2 Optical repeater
2,2a, 2b Mach-Zehnder interferometer
3,3a, 3b Laser diode
4,4a, 4b, 23_1,23_2,23a_1,23a_2,23b_1,23b_2,9,9a, 9b Splitter
21_1,21_2,21a_1,21a_2,21b_1,21b_2 phase adjuster
22_1,22_2,22a_1,22a_2,22b_1,22b_2 bandpass filter (BPF)
24,24a, 24b multiplexer
7,7a, 7b Optical amplifier
8,8a, 8b wavelength converter
10,10_1,10_2 Optical repeater
11,11_1,11_2 Optical switch
12,12_1,12_2 Optical switch controller
5 Amplitude / phase measuring instrument
6 Control unit
L1, L1_1, L1_2 Working (standby) optical transmission line
L2, L2_1, L2_2 Standby (working) optical transmission line
1000,1001 nodes (switches, routers)
IF maintenance interface (control line)
In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (5)

Redundant input and output terminals;
A phase adjustment unit that mutually adjusts and combines the phases of the input signal light to each input terminal;
An optical amplifier that amplifies the output signal light from the phase adjustment unit to a predetermined level;
A branching section for branching the output signal light of the optical amplifier to each output terminal;
An optical repeater comprising: In claim 1,
The phase adjustment unit is a Mach-Zehnder interferometer, and the branching unit returns the wavelength of the output signal light from the optical amplifier to the same wavelength as the input signal light, and the output of the wavelength converter An optical repeater comprising a splitter for branching signal light to each output terminal. In claim 2,
The Mach-Zehnder interferometer includes a common CW light source, a redundant phase adjuster that modulates the CW light with each input signal light and performs phase adjustment, and an input output from each phase adjuster Of the signal light wavelength component and the modulated CW light wavelength component, a redundant bandpass filter that passes only the CW light wavelength component, and a redundant splitter that branches the output light of each bandpass filter, A multiplexer that multiplexes one output light of each splitter, and a control unit that controls the phase adjuster so as to match each other by measuring the phase difference of the other output light of each splitter An optical repeater characterized by 4. An optical repeater comprising: a plurality of optical repeaters according to claim 1; and an optical switch that switches input signal light of each optical repeater based on a control signal. In claim 4,
The optical repeater is characterized in that the control signal is given to each optical switch via the control line from the phase adjusting unit or the opposite node that detects the transmission path failure.

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