JP6508715B2 - Wavelength multiplexing optical network system, branching apparatus and control method thereof - Google Patents

Description

  The present invention relates to a wavelength division multiplexing optical network system, a branching apparatus, and a control method thereof for improving security in communication of wavelength division multiplexing optical networks.

  A long distance wavelength division multiplexing optical communication network system (OADM: Optical add-drop multiplexer) constructs a long distance network with an optical transmission line such as a submarine cable. In the construction of this network, a branching apparatus is used which branches an optical transmission line from the middle of the optical transmission line. A plurality of relay devices are provided in the middle of each of the optical transmission paths to make the light output have a constant level. A signal in which a signal used for communication between other locations is multiplexed is transmitted to the optical transmission line branched from the branching device. In a wavelength-multiplexed optical communication network system, a network is often configured by forming a consortium in multiple countries and companies. Therefore, when a signal used for communication between other locations is input to the terminal apparatus at the branch destination, there is a possibility that communication between the other locations may be intercepted.

  Related to this, there is a wavelength multiplexing optical network system described in Patent Document 1 as a technology for improving the security of the wavelength multiplexing optical network. In this wavelength multiplexing optical network system, a branching unit is provided in the middle of an optical transmission line connecting between two terminal station apparatuses, and a branching terminal unit is connected to the optical transmission line branched by the branching unit. There is. Then, a signal in which the first signal used for communication between the two points is multiplexed is transmitted to the branched optical transmission line.

  A cutoff filter is provided before the branch destination terminal apparatus to separate the first signal from the multiplexed signal. Further, in this wavelength multiplexing optical network system, transmission means for multiplexing the dummy signal to the transmission signal in order to compensate the power of the signal light corresponding to the first signal reduced by the cutoff filter in the branch destination terminal apparatus It is provided. Thus, the wavelength division multiplexing optical network system prevents interception of the first signal at the branch destination terminal apparatus.

JP, 2011-82751, A

According to the wavelength division multiplexing optical network system of Patent Document 1, the blocking filter can block the first signal used for communication between other sites. However, according to this wavelength multiplexing optical network system, a blocking filter must be provided for each terminal device at the branch destination, and the step of installing the blocking filter occurs at the installation location of each terminal device. Further, the first signal is multiplexed and transmitted to the branched optical transmission line, and there is a possibility that the first signal may be intercepted in the middle of the branched transmission line.
An object of the present invention is to provide a wavelength multiplexing optical network system, a branching apparatus, and a control method therefor that can simplify the apparatus configuration while improving security in wavelength multiplexing optical communication.

A wavelength division multiplexing optical network system according to the present invention comprises a first terminal device, a second terminal device connected to the first terminal device, the first terminal device, and the second terminal device. A branching unit connected between the terminal device and a third terminal unit connected to the branching unit, and a connection between each of the first to third terminal units and the branching unit A plurality of relay devices, and
The branching device respectively transmits a first signal for the second terminal device and a second signal for the third terminal device, which are multiplexed and output from the first terminal device. Signal separation means for separating;
Signal degradation means for degrading the separated first signal;
And signal multiplexing means for multiplexing the deteriorated first signal and the second signal and outputting the multiplexed signal to the third terminal apparatus via the relay device.

The branching apparatus according to the present invention is connected between the first terminal apparatus and the second terminal apparatus connected, and the third terminal apparatus is connected by branching, and the first to third terminals are connected. A branch apparatus in which a plurality of relay apparatuses are respectively connected between the terminal apparatus of
Signal separation means for separating the first signal for the second terminal device multiplexed and outputted from the first terminal device and the second signal for the third terminal device respectively When,
Signal degradation means for degrading the separated first signal;
And signal multiplexing means for multiplexing the deteriorated first signal and the second signal and outputting the multiplexed signal to the third terminal apparatus via the relay device.

The control method of a branching apparatus according to the present invention is connected between a first terminal apparatus and a second terminal apparatus connected, and a third terminal apparatus is branched and connected; A control method of a branching unit in which a plurality of relay apparatuses are respectively connected between the terminal apparatus and the third terminal apparatus,
Respectively separating a first signal for the second terminal device multiplexed and output from the first terminal device and a second signal for the third terminal device;
Degrading the separated first signal,
The computer is caused to execute a process of multiplexing the deteriorated first signal and the second signal and outputting the multiplexed first signal to the third terminal apparatus via the relay device.

  According to the wavelength multiplexing optical network system, the branching apparatus, and the control method thereof according to the present invention, it is possible to simplify the apparatus configuration while improving the security in the wavelength multiplexing optical communication.

FIG. 1 is a block diagram showing a wavelength division multiplexing optical network system according to the present invention. 5 is a flowchart showing the operation of the wavelength multiplexing optical network system. FIG. 7 is a block diagram showing a modification of the wavelength multiplexing optical network system. FIG. 1 is a block diagram illustrating a related wavelength multiplexing optical network system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, security issues of the related wavelength multiplexing optical network system 80 will be described. As shown in FIG. 4, in the wavelength multiplexing optical network system 80, the first terminal device A and the second terminal device B are connected via the optical transmission line 30. Between the first terminal device A and the second terminal device B, a branch unit (BU: Branch Unit) 81 that branches the optical transmission path 30 is connected.

  The third terminal apparatus C is connected to the optical transmission line 32 branched from the branching device 81. The power of the signal light is maintained at a constant level in each of the optical transmission paths 30 and 32 between the first terminal device A, the second terminal device B, the third terminal device C, and the branching device 81. A plurality of relay devices R1, R2, and R8 are connected.

  The relay devices R1, R2, and R8 are erbium-doped optical fiber amplifiers (EDFAs) using the existing APC control (Automatic Power Control: constant power control) in the optical network system. The APC-controlled EDFA is mainly used in existing optical network systems because it can simplify the internal configuration. A general technique can be used for the configuration and control method of the APC control, and the description is omitted.

  In the wavelength multiplexing optical network system 80, information communication is performed among the first terminal device A, the second terminal device B and the third terminal device C. The first terminal device A transmits a first signal S to the second terminal device B. The first terminal device A transmits a second signal L to the third terminal device C. The third terminal device C transmits a third signal M to the second terminal device B. When the first terminal device A transmits the second signal L to the third terminal device C through the branching device 81, the first signal S is also multiplexed with the second signal L and simultaneously transmitted.

  This is because a general APC-controlled EDFA is used for the repeaters R1, R2 and R8 of the optical transmission lines 30 and 32, and in order to keep the gain of the repeaters R1, R2 and R8 constant, the optical input It is because it is calculated | required that power is a fixed value. Therefore, when communicating from the first terminal device A to the third terminal device C, it is not possible to output only the second signal L, and in order to make the input power of the EDFA constant, It is necessary to simultaneously output the second signal L.

  Here, if it is attempted to provide the branching device 81 with a cutoff filter for blocking the first signal S and only the second signal L is to be transmitted, the output level of the signal from the branching device 81 falls and the signal transmission characteristics deteriorate. Further, in general, no dummy light source is mounted on the branching device 81, and a method of maintaining the signal output level with the dummy light source after the first signal S is cut off can not be applied. Therefore, in the wavelength multiplexing optical network system 80, the first terminal device C has to be transmitted without excluding the first signal S.

  As a result, since the first terminal device C can receive the first signal S, there is a possibility that the information of the first signal S used for communication between other locations may be leaked. The wavelength multiplexing optical network system 50, which is a system for improving the security of communication between other sites, will be described below.

  As shown in FIG. 1, the wavelength division multiplexing optical network system 50 is a system for performing information communication among each of the first terminal device A, the second terminal device B and the third terminal device C. . The arrangement relation of each component is the same as that of the above-mentioned wavelength multiplexing optical network system 80, and the same reference numeral is used for the same component, and the overlapping description is appropriately omitted. Between the first terminal device A and the second terminal device B, the branching device 101 for branching the optical transmission path 30 is connected. In the wavelength multiplexing optical network system 50, the first terminal device A multiplexes the first signal S and the second signal L, and outputs the multiplexed signal P1. The third terminal device C receives the second signal L and outputs a third signal M. The second terminal device B receives the multiplexed signal P4 in which the first signal S and the third signal M are multiplexed.

  The branching apparatus 101 includes an optical LPF (Low-level filter 110) that branches a signal, a multiplexer 112 that multiplexes the signal, and filters the multiplexed signal to extract a signal having a frequency lower than a specific frequency. (pass filter) 102, an optical HPF (High-pass filter) 201 for filtering the multiplexed signal to extract a signal having a frequency higher than a specific frequency, and a multiplex branched for the third terminal apparatus C (De Multiplexer) 301 for separating the signal P1 into the first signal S and the second signal L, the signal receiver 311 for receiving the separated first signal S, and deterioration of the first signal S A polarization scrambler 302 that generates a signal S1 and a polarization scrambler controller 31 that controls the polarization scrambler 302. When a CPL (optical coupler) (signal synthesizing means) 303 for combining the second signal L which is separated and degraded signal S1, in being configured.

  Here, the DMUX 301 is a signal separation unit. The polarization scrambler controller 312 and the polarization scrambler 302 constitute signal degradation means. The multiplexed signal P1 of the first signal S and the second signal L output from the first terminal device A is input to the branching device 101 through the relay devices R1 and R2. A polarization control signal for polarization control is attached to the header portion of the first signal S output from the first terminal apparatus A, as described later. The multiplexed signal P1 is branched into the multiplexed signal P1 for the second terminal apparatus B and the multiplexed signal P1 for the third terminal apparatus C in the branching unit 101 in the branching unit 110. By the LPF 102 in the branching apparatus 101, the multiplexed signal P1 for the second terminal apparatus B is separated into only the first signal S.

  The multiplexed signal (branch drop signal) P1 branched for the third terminal device C is input to the DMUX 301 and separated into a first signal S and a second signal L, respectively. As an optical module used for DUMX 301, it is possible to use a WSS (Wavelength Selective Switch) capable of changing the filter shape into an arbitrary waveform, an OADM filter having a fixed filter shape, or the like. The second signal L separated by the DMUX 301 is input to the CPL 303. The first signal S separated by the DMUX 301 is input to the signal receiver 311.

  The signal receiver 311 receives the polarization control signal incidental to the header portion of the first signal S. The polarization scrambler controller 312 controls the polarization scrambler 302 based on the polarization control signal received by the signal receiver 311. The polarization scrambler controller 312 controls the polarization scrambler 302 based on the polarization control signal to adjust the degree of deterioration of the deteriorated signal S1. The polarization scrambler 302 applies polarization rotation to the first signal S to generate a degraded signal S1 degraded to the unreceivable signal characteristics.

  The polarization scrambler 302 applies high-speed rotation to the polarization of the first signal S that is not necessary for communication. Then, the signal characteristics of the first signal S deteriorate due to the non-linear effect due to the high speed rotation of the polarization, so that the first signal S can not be received on the third terminal apparatus C (branch station) side.

  A general method can be used for the mechanism of signal characteristic deterioration by polarization rotation, and the detailed description is omitted. The deterioration signal S1 whose signal characteristics are deteriorated and the second signal L branched by the DUMX 301 are multiplexed (multiplexed) by the CPL 303, and the third terminal apparatus as the multiplexed signal P2 through the relay devices R5 and R6. Output towards C. The third terminal device C receives the multiplexed signal P2 and separates the second signal L from the multiplexed signal P2.

  The third terminal device C communicates with the first terminal device A using only the second signal L. The third terminal device C outputs the third signal M to the second terminal device B. At this time, the third terminal device C multiplexes the pseudo light (dummy signal) DL: Dummy Light with the third signal M, and outputs it as a multiplexed signal P3.

  This is because, as described above, it is required that the optical input power be a constant value in order to keep the gain of the relay devices R7 and R8 constant, and the third terminal apparatus C to the third signal This is because only M can not be output, and in order to make the input power of the EDFA constant, it is necessary to simultaneously output the third signal M and the pseudo light DL. The multiplexed signal P3 output from the third terminal device C is input to the branching device 101 through the relay devices R7 and R8. When the multiplexed signal P3 passes through the HPF 201, only the third signal M is output.

  In the branching apparatus 101, the first signal S cut out of the multiplexed signal P1 by the LPF 102 and the third signal M cut out of the multiplexed signal P3 by the HPF 201 are multiplexed by the multiplexing unit 112, and the multiplexed signal P4 is output. Do.

  The multiplexed signal P4 output from the branching device 101 is input to the second terminal device B through the relay devices R3 and R4. The second terminal device B communicates with the station A by receiving the first signal S, and communicates with the station C by receiving the third signal M.

  Next, the operation of the wavelength multiplexing optical network system 50 will be described.

  As shown in FIG. 2, in the wavelength division multiplexing optical network system 50, the multiplexed signal P1 input from the first terminal apparatus A is input to the branching apparatus 101. In the branching device 101, the DMUX 301 separates the multiplexed signal P1 into the first signal S and the second signal L (S100). The signal receiver 311 receives the polarization control signal attached to the header portion of the first signal S, and the polarization scrambler controller 312 controls the polarization scrambler 302 based on the polarization control signal.

  The polarization scrambler 302 adds polarization rotation to the first signal S to generate a degraded signal S1 degraded to the unreceivable signal characteristics (S101). The CPL 303 multiplexes the deterioration signal S1 and the second signal L branched by the DUMX 301, and outputs the multiplexed signal P2 to the third terminal device C via the relay devices R5 and R6 (S102).

  The third terminal device C receives the multiplexed signal P2, separates the second signal L from the multiplexed signal P2, and receives the second signal L. The third terminal device C multiplexes the pseudo light DL into the third signal M, and outputs the multiplexed signal P3 to the branching device 101 (S103). The branching apparatus 101 multiplexes the third signal M separated from the multiplexed signal P3 and the first signal S separated from the multiplexed signal P1 to generate a multiplexed signal P4 and outputs the multiplexed signal P4 to the second terminal apparatus B. (S104).

  The control method of each component in the wavelength multiplexing optical network system 50 described above may be realized using a semiconductor processing apparatus including an application specific integrated circuit (ASIC). Also, these processes may be realized by causing a computer system including at least one processor (e.g. microprocessor, MPU, DSP (Digital Signal Processor)) to execute a program. Specifically, one or a plurality of programs including a group of instructions for causing a computer system to execute an algorithm related to the transmission signal processing or the reception signal processing may be created, and the program may be supplied to the computer.

  These programs can be stored and supplied to a computer using various types of non-transitory computer readable media. Non-transitory computer readable media include tangible storage media of various types.

  Examples of non-transitory computer readable media are magnetic recording media (eg flexible disk, magnetic tape, hard disk drive), magneto-optical recording media (eg magneto-optical disk), CD-ROM (Read Only Memory), CD-R, CD-R / W, semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable PROM), flash ROM, RAM (random access memory)) are included.

  Also, the programs may be supplied to the computer by various types of transitory computer readable media. Examples of temporary computer readable media include electrical signals, light signals, and electromagnetic waves. The temporary computer readable medium can provide the program to the computer via a wired communication path such as electric wire and optical fiber, or a wireless communication path.

  According to the wavelength multiplexing optical network system 50 of the present invention, only the signal necessary for the third terminal station C on the branch side is received without attenuating the optical power of the signal by rotating the polarization plane of the first signal S Can improve security. That is, the wavelength multiplexing optical network system 50 according to the present invention converts only the wavelength of the first signal S into unreceivable data without reducing the optical level of the signal output from the branching device 101. Thereby, the wavelength multiplexing optical network system 50 can perform polarization scrambling on the first signal S and convert it into an unreceivable signal while keeping the output level from the branching device 101 constant.

  Then, the wavelength multiplexing optical network system 50 can make the reception of the first signal S impossible, and can prevent the secret information acquisition by a specific country, company or third party in which the third terminal apparatus C is provided. . Moreover, according to the configuration of the wavelength multiplexing optical network system 50 according to the present invention, it is possible to improve the security aspect while diverting the related optical network OADM system, and the device configuration can be simplified.

  In addition, this invention is not limited to said embodiment, It is possible to change suitably in the range which does not deviate from the meaning. For example, it can also be configured as in the following modification.

  As shown in FIG. 3, the wavelength multiplexing optical network system 60 has the same arrangement as the wavelength multiplexing optical network system 50. In the wavelength multiplexing optical network system 60, the internal configuration and processing method of the branching device 601 are different from those of the branching device 101 of the wavelength multiplexing optical network system 50. In the following description, the same components as the components of the wavelength multiplexing optical network system 50 use the same reference numerals, and the description of the same configuration and operation will be omitted.

  The branching unit 601 includes branching units 610 and 611, a multiplexing unit 612, a DMUX 602, an optical HPF 605, a polarization scrambler 604, a CPL 603, a signal receiver 611, a polarization scrambler controller 612, and an optical HPF 606. There is. The multiplexed signal P1 input to the branching unit 601 is divided into the multiplexed signal P1 for the second terminal apparatus B and the multiplexed signal P1 for the third terminal apparatus C at the branching unit 610. The multiplexed signal P1 for the third terminal device C becomes only the second signal L when passing through the HPF 605. The multiplexed signal P1 directed to the second terminal device B is separated by the DMUX 602 and becomes only the first signal S.

  The first signal S demultiplexed by the DUMX 602 is branched by the branching unit 611 and input to the signal receiver 611. The signal receiver 611 receives a polarization control signal attached to the first signal S. The polarization scrambler controller 612 controls the polarization scrambler 612 based on the polarization control signal received by the signal receiver 611. The first signal S passes through the polarization scrambler 612 to generate the degraded signal S1. The deterioration signal S1 is multiplexed with the second signal L at the CPL 603 to generate a multiplexed signal P2. Thereafter, the multiplexed signal P2 is outputted from the branching unit 601 to the third terminal device C.

  The third terminal device C receives the second signal L, multiplexes the third signal M and the pseudo light DL to generate a multiplexed signal P 3, and transmits the multiplexed signal P 3 to the second terminal device B. In the branching unit 601, the multiplexed signal P3 passes through the HPF 606 and becomes the third signal M. After that, the third signal M and the signal S for the second terminal device B are multiplexed by the multiplexer 611 and transmitted toward the second terminal device B. The effect of the branching unit 601 is similar to that of the wavelength multiplexing optical network system 50.

Reference Signs List 30 optical transmission line 32 optical transmission line 50 wavelength multiplexing optical network system 60 wavelength multiplexing optical network system 80 wavelength multiplexing optical network system 81 branching device 101 branching device 102 LPF
201 HPF
301 DMUX
302 Polarization scrambler 303 CPL
311 Signal Receiver 312 Polarization Scrambler Controller 601 Branching Device 602 DMUX
603 CPL
604 Polarization scrambler 605 HPF
606 HPF
611 signal receiver 612 polarization scrambler controller A first terminal device B second terminal device C third terminal device DL pseudo light L second signal M third signal P1 to P4 multiplexed signal R1 To R8 relay device S first signal S1 deterioration signal

Claims (7)

A first terminal apparatus, a second terminal apparatus connected to the first terminal apparatus, and a branch connected between the first terminal apparatus and the second terminal apparatus An apparatus, a third terminal apparatus connected to the branching apparatus, and a plurality of relay apparatuses connected between each of the first to third terminal apparatuses and the branching apparatus ,
The branching device respectively transmits a first signal for the second terminal device and a second signal for the third terminal device, which are multiplexed and output from the first terminal device. Signal separation means for separating;
Signal degradation means for degrading the separated first signal;
Possess a deteriorated the first signal, and a signal multiplexing means for outputting said second signal to said third terminal station through the repeater are multiplexed,
The signal degradation means degrades the first signal based on a polarization control signal attached to the first signal.
Wavelength-multiplexed optical network system. The signal deterioration means adjusts the degree of deterioration of the first signal based on the polarization control signal.
A wavelength multiplexing optical network system according to claim 1 . The signal degradation means degrades the first signal by polarization rotation.
A wavelength multiplexing optical network system according to claim 1 or 2 . Before Symbol third end station device, and a third signal and a dummy signal for the second terminal devices are multiplexed, and outputs it to the second terminal device via the relay device,
The wavelength multiplexing optical network system according to any one of claims 1 to 3 . It is connected between the first terminal device and the second terminal device connected, the third terminal device is branched and connected, and between the first to third terminal devices. A branching unit to which a plurality of relay units are respectively connected,
Signal separation means for separating the first signal for the second terminal device multiplexed and outputted from the first terminal device and the second signal for the third terminal device respectively When,
Signal degradation means for degrading the separated first signal;
Possess a deteriorated the first signal, and a signal multiplexing means for outputting said second signal to said third terminal station through the repeater are multiplexed,
The signal degradation means degrades the first signal based on a polarization control signal attached to the first signal.
Branching device. The signal deterioration means adjusts the degree of deterioration of the first signal based on the polarization control signal.
The branching apparatus according to claim 5 . It is connected between the first terminal device and the second terminal device connected, the third terminal device is branched and connected, and between the first to third terminal devices. A control method of a branch apparatus to which a plurality of relay apparatuses are respectively connected,
Respectively separating a first signal for the second terminal device multiplexed and output from the first terminal device and a second signal for the third terminal device;
Degrading the separated first signal based on a polarization control signal incidental to the first signal ,
Allowing a computer to execute a process of multiplexing the deteriorated first signal and the second signal and outputting the multiplexed first signal to the third terminal apparatus via the relay device.
Control method of branching apparatus.

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