JP2000332703A - Optical communication monitor method, optical communication monitor, and optical communication monitor system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical communication monitor method or the like by which the replacement of an optical monitor signal is easily conducted at a low cost, without the need for converting the light signal as is into a monitor signal. SOLUTION: A spread spectrum section 108i in an optical communication monitor 100 provided to a node 1 applies spread spectrum processing to a monitor signal with a frequency fi outputted from a monitor signal generating circuit 1071, by using a spread code PN1 given by a spread code provision section 112. The monitor signal with the frequency fi that receives spread spectrum processing is superimposed on a main signal S1 outputted from a main signal source 1011, and a transmitter 109 outputs the superimposed signal as an optical signal. A multiplexer 110 multiplexes the optical signals, and the multiplexed signal is transmitted to the transmission line of a section #1. A monitor signal receiving spread spectrum processing with a new spread code PN2 is superimposed on the optical signal which reached from the transmission line of the section #1 in an optical communication monitor 120 provided to a node 2, without the need for converting the optical signal reached from the transmission line of the section #1 into an electrical signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an optical signal obtained by superimposing a monitoring signal for network monitoring on each of main signals,
An optical communication monitoring method and an optical communication monitoring device for transmitting the optical signal to a transmission line of a network and monitoring the network with the monitoring signal, and an optical communication monitoring device provided with an optical communication monitoring device at each node of the network It is about the system.

[0002]

2. Description of the Related Art An optical communication monitoring method, an optical communication monitoring apparatus and an optical communication monitoring system for monitoring a network of an optical communication system are disclosed in, for example, JP-A-6-21897 and JP-A-10-242939. I have. The optical communication monitoring technology disclosed in these publications superimposes a low-frequency monitoring signal for network monitoring on each wavelength-multiplexed main signal to generate an optical signal, and converts the optical signal into a transmission path of a network of an optical communication system. And the network is monitored by this monitoring signal. Then, the optical repeater amplifier in the network detects the wave number by detecting the monitoring signal included in the arrived optical signal, and controls the gain at the time of optical amplification of the optical signal based on the wave number, thereby controlling The output level of the optical signal is controlled to be constant with respect to the wavelength.

[0003] Reference 1 "Y. Hamazumi, et al.," T
ransmission Capacity of OpticalPath Overhead Trans
fer Scheme Using Pilot Tone for Optical Path Netwo
rk ", Journal of Lightwave Technology, Vol.15, No.1
2, pp.2197-2205 (1997) ”and Reference 2“ GR
Hill, et al., "A Transfer Network layer Based on O
ptical Network Elements ", Journal of Lightwave Tec
hnology, Vol. 11, No. 5/6, pp. 667-679 (1993)], respectively, are reported on transmission characteristics of supervisory signals in networks.

Further, those disclosed in JP-A-9-215072 and JP-A-10-336108 are disclosed in
By superimposing a monitor signal (pilot tone signal) having a wavelength or a frequency unique to the main signal on each of a plurality of main signals having different wavelengths, and detecting the monitor signal at a switch output port in the optical path cross-connect system, It monitors the setting state of the optical path. Also,
Reference 3 "F. Heismann, et al.," Signal Tracking and
Performance Monitoring In Multi-Wavelength Optica
l Networks ", 22nd European Conference on Optical C
ommunications- ECOC'98, WeB.2, pp.3.47-3.50 (1996)
"Describes replacement of monitoring signals in the optical path cross-connect system.

FIG. 6 is a diagram for explaining an example of the configuration of a conventional optical communication monitoring device and optical communication monitoring system. FIG. 1 shows two optical communication monitoring apparatuses 10 and 20 provided at nodes of a network of an optical communication system, and two optical relay amplifiers 30 and 40 provided in a section between nodes. I have. In the following, the suffix i represents any one of the numerals 1 to 3, unless otherwise specified.

The optical communication monitoring device 10 provided in the node 1
Then, the monitor signal of the frequency f _i output from the monitor signal generation circuit 17 _i is superimposed on the main signal S _i output from the main signal source 11 _i . The frequency f _{i of the} monitoring signal is specific to the main signal S _i or the wavelength of the main signal S _i . The main signal S _i on which the supervisory signal is superimposed is output as an optical signal from the transmitter 15 _i , and the optical signal is multiplexed by the multiplexer 18, and the optical signal in the middle of the transmission path of the section # 1 is transmitted. The signal is transmitted via the amplifier 30 to the optical communication monitoring device 20 provided at the node 2 at the next stage.

In the optical communication monitoring device 20, the arriving optical signal is split by the splitter 22. And the main signal source 11
_The optical signal including the main signal S _i and the monitoring signal f _i output from _i is received by the receiver 23 _i and converted into an electric signal. The electrical signals, along with only the main signal S _i component from the high-pass filter 24 _i is removed monitoring signal f _i component by the high-pass filter 24 _i is output, the monitor signal f _i is detected by the monitoring signal detector 26 _i Is done.

The monitor signal of the frequency f _i output from the monitor signal generation circuit 27 _i is superimposed on the main signal S _i output from the high-pass filter 24 _i (i = 1, 2). However, the main signal S ₃ output from the high pass filter 24 _3, monitor signal outputted from the monitor signal generating circuit 27 ₃ frequencies f ₄ is superimposed. That is, the frequency of the supervisory signal superimposed on the main signal S ₃ is replaced by f ₃ to f _4.
Then, the main signal S _i on which the new monitoring signal is superimposed is output as an optical signal from the transmitter 25 _i , and this optical signal is multiplexed by the multiplexer 28, and in the middle of the transmission path of the section # 2. Is transmitted to the next-stage node via the optical repeater amplifier 40 located in the first stage.

In each of the optical repeater amplifiers 30 and 40 in this optical communication system, the arriving optical signal is demultiplexed by a demultiplexer, and each demultiplexed optical signal is received by a receiver and converted into an electric signal. monitor signal f _i superimposed on the electrical signal is detected. The wavenumber is detected based on the detected monitor signal f _i, the gain at the time of optical amplification with respect to optical signals based on the wave number is controlled. In this way, the output level of the optical signal is controlled to be constant for each wavelength.

[0010]

Conventional optical communication monitoring method of the [SUMMARY OF THE INVENTION] In the optical communication monitoring apparatus and optical communication monitoring system, f at node 2, from the main signal S ₃ frequency of the monitoring signal superimposed on the f ₃ Replaced with ₄ . Such replacement of the monitoring signal is performed when tracing the transmission path of the optical signal, when converting the wavelength of the main signal during transmission (when superimposing a monitoring signal having a frequency unique to the wavelength of the main signal), and the like. Is required.

In the above-described conventional optical communication monitoring method and the like, when the monitoring signal is replaced, the arriving optical signal is received by the receiver 23.
_i, is converted into an electric signal, and the monitoring signal included in the electric signal is removed by the high-pass filter 24 _i .
The main signal S _i output from the high-pass filter 24 _i is superimposed on a monitor signal of a new frequency f _i output from the monitor signal generation circuit 27 _i to form an optical signal. As described above, the replacement of the monitoring signal accompanied by the conversion between the optical signal and the electric signal limits the main signal to be transmitted, and it may be difficult to realize the transparency.

Therefore, it is preferable to replace the monitoring signal with the optical signal without converting it into an electric signal. For example, in the above document 3, the monitoring signal is removed by negatively feeding back the optical signal. However, a system for performing such processing is inevitably expensive. Further, in order to completely remove the monitoring signal, extremely high-level control is required for the gain and phase at the time of negative feedback of the optical signal.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an optical communication monitoring method capable of inexpensively and easily replacing a monitoring signal with an optical signal without converting it into an electric signal. It is an object to provide an optical communication monitoring device and an optical communication monitoring system.

[0014]

According to the optical communication monitoring method of the present invention, a monitoring signal for network monitoring is superimposed on each main signal to form an optical signal, and the optical signal is transmitted to a transmission line of a network. An optical communication monitoring method for monitoring a network by using a monitoring signal, comprising: (1) a first node of the network spreads a monitoring signal with a spreading code corresponding to a transmission path to which a main signal is to be transmitted; (2) The second node of the network receives the optical signal arriving via the transmission line and converts it into an electric signal at the second node of the network. The spectrum signal is despread with a spreading code to restore the monitor signal superimposed on the electrical signal, and the restored monitor signal is detected.

A first optical communication monitoring apparatus according to the present invention superimposes a monitoring signal for network monitoring on each main signal to form an optical signal, transmits this optical signal to a transmission line of a network, and transmits the optical signal. An optical communication monitoring device for monitoring a network by: (1) a spectrum spreading means for spectrum-spreading a monitoring signal with a spreading code corresponding to a transmission path to which a main signal is to be transmitted; and (2) a spectrum spreading means by the spectrum spreading means. Transmitting means for transmitting an optical signal, in which the monitored signal is superimposed on the main signal, to a transmission path, and (3) first spreading code providing means for providing a spreading code to the spectrum spreading means. .

A second optical communication monitoring apparatus according to the present invention superimposes a monitoring signal for network monitoring on each of the main signals to form an optical signal, transmits this optical signal to a transmission line of a network, and An optical communication monitoring device for monitoring a network by: (1) receiving means for receiving an optical signal arriving via a transmission line, converting the signal into an electric signal, and outputting the electric signal; and (2) receiving means for receiving the signal. Surveillance signal restoring means for despreading the output electric signal with a spread code and restoring a monitor signal superimposed on the electric signal;
(3) a monitoring signal detecting means for detecting the monitoring signal restored by the monitoring signal restoring means; and (4) a second spreading code providing means for providing a spreading code to the monitoring signal restoring means. .

According to the optical communication monitoring method, the first optical communication monitoring device, and the second optical communication monitoring device, the first node (first optical communication monitoring device) of the network includes:
The monitoring signal is spread with a spreading code corresponding to the transmission path to which the main signal is to be transmitted, and the main signal on which the spectrum-spread monitoring signal is superimposed is transmitted to the transmission path as an optical signal. At this time, the monitor signal may be superimposed on the optical signal after converting the main signal into an optical signal, or the monitor signal may be converted into an optical signal after being superimposed on the main signal. On the other hand, at the second node (second optical communication monitoring device) of the network, the optical signal arriving via the transmission path is received and converted into an electric signal, and this electric signal is spectrum despread with a spreading code. The monitoring signal superimposed on the electric signal is restored, and the restored monitoring signal is detected.

Further, a supervisory signal that has been spectrum-spread by a new spreading code corresponding to the transmission path to the next-stage node is superimposed and transmitted. Here, as the spreading code according to the transmission path, a code (for example, an M-sequence code) having a weak cross-correlation with respect to the auto-correlation is preferable. By doing so, it is only necessary to superimpose a new monitoring signal without removing the original monitoring signal. As described above, the replacement of the monitoring signal can be performed easily and inexpensively with the optical signal being used without being converted into the electric signal.

A node that performs only transmission may be provided with a first optical communication monitoring device, and a node that performs only reception may be provided with a second optical communication monitoring device. An optical communication monitoring device having both functions of the first and second optical communication monitoring devices is provided in a node that performs both.

The optical communication monitoring method according to the present invention is characterized in that, at the second node, spectrum despreading is sequentially performed with a spreading code corresponding to each transmission path of the network. In the second optical communication monitoring apparatus according to the present invention, the second spreading code assigning means sequentially gives a spreading code corresponding to each transmission path of the network to the monitoring signal restoring means. In this case, the transmission path of the optical signal that has reached the second node (the second optical communication monitoring device) can be traced based on which spreading code used to recover and detect the monitoring signal. In particular, spreading codes specific to sections between nodes of the network are preferred for tracing the transmission path.

Further, in the optical communication monitoring method according to the present invention, the first node sends a spread code used for spread spectrum as an optical signal to the optical transmission line, and the second node transmits the spread code as an optical signal. The received spread signal is received and spectrum despreading is performed with the received spread code. The first optical communication monitoring device is a first optical communication monitoring device.
And a spread code transmitting means for transmitting a spread code given to the spectrum spread means by the spread code assigning means to the optical transmission path as an optical signal. The second optical communication monitoring device further comprises a spread code receiving means for receiving the spread signal arriving as the optical signal, and the second spread code providing means converts the spread code received by the spread code receiving means to the monitor signal restoring means. To be given. In this case, the spreading code generated in the first node (first optical communication monitoring device) is transmitted to the second node (second optical communication monitoring device), so that the second node performs spreading. There is no need to generate the code itself. Therefore, the system configuration is simplified.

Also, in the optical communication monitoring method according to the present invention, the first node sends the phase information of the spread code used in the spread spectrum as an optical signal to the optical transmission line, and the second node The method is characterized in that phase information arrived as an optical signal is received, and spectrum despreading is performed with a spreading code based on the received phase information. First
The optical communication monitoring device further comprises a spread code phase information transmitting means for transmitting phase information of a spread code provided to the spread spectrum means by the first spread code providing means to the optical transmission line as an optical signal. . The second optical communication monitoring device further includes a spread code phase information receiving means for receiving phase information of the spread signal arriving as the optical signal, and the second spread code assigning means is received by the spread code phase information receiving means. A spreading code is provided to the monitor signal restoring means based on the phase information. In this case, the phase information of the spreading code generated at the first node (first optical communication monitoring device) is transmitted to the second node (second optical communication monitoring device), and the second node transmits the phase information to the second node. Since the spreading code can be generated based on the phase information, the second node does not need a circuit for synchronization acquisition and synchronization tracking. Therefore, the system configuration is simplified.

In the optical communication monitoring system according to the present invention, a monitoring signal for network monitoring is superimposed on each of the main signals to form an optical signal, and the optical signal is transmitted to a transmission line of the network, and the network is controlled by the monitoring signal. An optical communication monitoring system for monitoring, wherein each of the nodes of the network is provided with the above optical communication monitoring device. According to this optical communication monitoring system, it is possible to easily and inexpensively replace a monitoring signal with an optical signal without converting it into an electric signal.

[0024]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description. In the following, the suffix i represents any of the numerals 1 to 3 unless otherwise specified.

(First Embodiment) First, a first embodiment of an optical communication monitoring method, an optical communication monitoring device, and an optical communication monitoring system according to the present invention will be described. FIG. 1 is a diagram illustrating a configuration example of an optical communication monitoring device and an optical communication monitoring system according to the first embodiment. This figure shows three optical communication monitoring devices 100, 120, and 140 provided at nodes of the network of the optical communication system, and two optical repeater amplifiers 200 and 210 provided in the middle of a section between the nodes. Have been.

Optical communication monitoring device 10 provided in node 1
0 is a main signal source 101 _{1 to} 101 ₃ , a monitoring signal generation circuit 1
07 _{1 to} 107 ₃ , spread spectrum parts 108 ₁ to 10
8 ₃ , transmitters 109 _{1 to} 109 ₃ , a multiplexer 110 and a spreading code assigning unit 112.

The main signal source 101 _i outputs a main signal S _i of a certain wavelength among the wavelength-multiplexed main signals as an electric signal. The monitoring signal generation circuit 107 _i generates and outputs a low frequency monitoring signal for monitoring the network of the frequency f _i . Spreading code assigning unit 112 generates a spreading code PN1 corresponding to transmission paths of the section # 1, and gives the spreading code PN1 spread spectrum unit 108 _i. Spread spectrum unit 108 _i is the spreading code PN1 given from the spread code imparting unit 112, a monitoring signal f _i output from the monitor signal generating circuit 107 _i to spectrum spread, the spread spectrum monitored signal f _i Is output. Transmitter 109 _i
Is output from the main signal source 101 _i and the main signal S _i, based on the monitor signal f _i which is spectrum spread by the spread spectrum unit 108 _i, a main signal spread spectrum monitored signal f _i is superimposed It outputs _Si as an optical signal. The multiplexer 110 multiplexes the optical signals output from the transmitters 109 _i and sends the multiplexed optical signal to the transmission path of section # 1.

Optical communication monitoring device 12 provided in node 2
0 indicates a demultiplexer 122, optical branching units 123 _{1 to} 123 ₃ , receivers 124 _{1 to} 124 ₃ , and monitor signal restoring units 125 _{1 to} 12 _1.
5 _3, the monitoring signal detecting circuit 126 ₁ to 126 _3, the monitoring signal generation circuit 127 ₁ to 127 _3, the spread spectrum unit 128 ₁
１２８128 ₃ , modulators 129 _{1 to} 129 ₃ , multiplexer 130,
And spreading code assigning sections 131 and 132.

The duplexer 122 is a transmission line of section # 1.
The multiplexed optical signal that arrives at node 2 is input and
This is split and output for each wavelength. Optical branching unit 123_iIs
Spread spectrum monitor signal f_iSuperimposed
No. S_iIs input from the demultiplexer 122 as an optical signal,
It branches into two and each receiver 124_iAnd modulator 129_iWhat
Output. Receiver 124_iIs a light branching unit 123_iReach from
Input optical signal and convert this optical signal to an electrical signal.
And outputs this electrical signal. Spreading code assigning section 131
Calculates the spreading code PN1 corresponding to the transmission path of section # 1.
The generated spreading code PN1 is transmitted to the monitor signal restoring unit 125._i
Give to. Monitoring signal restoration unit 125_iIs the spreading code assigning unit
With the spreading code PN1 given by 131, the receiving unit 124
_iDespreads the electrical signal output from the
The monitoring signal f superimposed on this electric signal _iRestore
Output. Monitor signal detection circuit 126_iRestore the monitoring signal
Part 125_iMonitor signal f output from_iIs detected.

The monitoring signal generation circuit 127 _i generates and outputs a low frequency monitoring signal for monitoring the network of the frequency f _i . The spreading code assigning unit 132 generates a spreading code PN2 corresponding to the transmission path of section # 2,
2 is given to the spread spectrum unit 128 _i . Spread spectrum unit 128 _i is the spreading code PN2 given from the spreading code assigning unit 132, a monitoring signal f _i output from the monitor signal generating circuit 127 _i to spectrum spread, the spread spectrum monitored signal f _i Is output. The modulator 129 _i includes: an optical signal arriving from the optical branching unit 123 _i ;
Based spread spectrum unit 128 _i to the monitoring signal f _i which is spectrum spread, and outputs the main signal S _i which spread spectrum monitored signal f _i is superimposed as an optical signal. The multiplexer 130 multiplexes the optical signals output from the modulators 129 _i and sends the multiplexed optical signal to the transmission path of section # 2.

Optical communication monitoring device 14 provided in node 3
0 indicates a demultiplexer 142, optical branching units 143 _{1 to} 143 ₃ , receivers 144 _{1 to} 144 ₃ , and monitor signal restoring units 145 _{1 to} 145
5 ₃ includes a monitoring signal detecting circuit 146 ₁ to 146 ₃ and the spreading code assigning unit 151.

The demultiplexer 142 receives the multiplexed optical signal that has arrived at the node 3 from the transmission line of section # 2, demultiplexes the multiplexed optical signal, and outputs the demultiplexed optical signal for each wavelength. The optical branching unit 143 _i
The main signal S _i on which the spread spectrum monitoring signal f _i is superimposed is input from the demultiplexer 142 as an optical signal, which is split into two and output to a receiver 144 _i and a modulator (not shown). I do. The receiver 144 _i receives the optical signal arriving from the optical branching section 143 _i, and converts the optical signal into an electric signal, and outputs the electric signal. Spreading code assigning section 15
1 is a spreading code PN2 corresponding to the transmission path of section # 2.
Is generated and the spreading code PN2 is converted to the monitor signal restoring unit 145
give to _i . The monitoring signal restoring unit 145 _i uses the spreading code PN2 given by the spreading code assigning unit 151 to
Spectrum despreading of the electric signal output from _i ,
A monitoring signal f _i that is superimposed on the electric signal to restore and output. The monitoring signal detection circuit 146 _i detects the monitoring signal f _i output from the monitoring signal restoration unit 145 _i .

Section # between node 1 and node 2
The optical repeater amplifier 200 provided in the middle of the
The optical signal output from the optical communication monitoring device 100 provided in the node 2 is input, the optical signal is optically amplified, and transmitted to the optical communication monitoring device 120 provided in the node 2. At this time, the arriving optical signal is demultiplexed by the demultiplexer, and each demultiplexed optical signal is received by the receiver to be an electric signal,
Monitor signal f _i that is superimposed on the electric signal is detected. The wavenumber is detected based on the detected monitor signal f _i, the gain at the time of optical amplification with respect to optical signals based on the wave number is controlled. In this way, the output level of the optical signal is controlled to be constant for each wavelength. The same applies to the optical repeater amplifier 210 provided in the section # 2 between the node 2 and the node 3.

Next, the operation of the optical communication monitoring device and the optical communication monitoring system according to the present embodiment will be described, and the optical communication monitoring method according to the present embodiment will be described.

Optical communication monitoring device 10 provided in node 1
At 0, the supervisory signal output from the supervisory signal generation circuit 107 _i is spread by the spread spectrum unit 108 _i with the spread code PN1 given from the spread code attaching unit 112 and output. The frequency f _{i of the} monitoring signal is
It is not always necessary to be unique to the main signal S _i or the wavelength of the main signal S _i output from the main signal source 101 _i , and for example, regardless of the wavelength of the main signal S _i or the main signal S _i , May be a fixed value. The main signal S _i output from the main signal source 101 _i, the monitoring signal f _i which is spectrum spread by the spread spectrum unit 108 _i is superimposed and outputted as an optical signal from the transmitter 109 _i. The optical signals output from the transmitters 109 _i are multiplexed by the multiplexer 110, and the multiplexed optical signals are transmitted to the section #.
1 transmission path.

In the optical repeater amplifier 200 provided in the middle of the transmission path of section # 1, the optical signal multiplexed and output from the optical communication monitoring device 100 is controlled so that the output level is controlled to be constant for each wavelength. Amplified. Then, the optically amplified optical signal is transmitted to the optical communication monitoring device 120.

The optical communication monitoring device 12 provided in the node 2
0, the node 2 is reached from the transmission path of section # 1.
The multiplexed optical signal is demultiplexed by the demultiplexer 122.
It is output for each wavelength. Light split by the splitter 122
Signal (monitoring signal f_iIs superimposed on the main signal S_i) Is a light branch
Part 123_i, And each is divided into receivers 124 _iYou
And modulator 129_iOutput to Optical branching unit 123_iFrom
Receiver 124_iReaches the receiver 124_iBy
The electric signal is converted into an electric signal, and this electric signal is output.
Receiver 124_iThe electrical signal output from the
Base 125_iFrom the spreading code assigning unit 131
Spectrum despread with the spread code PN1
Monitoring signal f superimposed on electric signal_iIs restored
Is forced. Then, the monitoring signal restoring unit 125_iOutput from
Monitoring signal f_iIs the monitor signal detection circuit 126_iDetected by
Is done.

[0038] Further, in the optical communication monitoring apparatus 120 provided in the node 2, the monitoring signal outputted from the monitor signal generating circuit 127 _i includes a spread spectrum unit 128 _i,
The spectrum is spread by the spreading code PN2 given by the spreading code giving unit 132 and output. Optical branching unit 123 _i
The optical signal reaching the modulator 129 _i from the modulator 129 _i
As a result, the monitoring signal f _{i that} has undergone spectrum spreading by the spectrum spreading section 128 _i is superimposed and output as an optical signal. Then, the optical signals output from the modulators 129 _i are multiplexed by the multiplexer 130, and the multiplexed optical signals are transmitted to the transmission path of the section # 2.

In the optical repeater amplifier 210 provided in the middle of the transmission line of section # 2, the optical signal multiplexed and output from the optical communication monitoring device 120 is controlled so that the output level is controlled to be constant for each wavelength. Amplified. Then, the optically amplified optical signal is transmitted to the optical communication monitoring device 140.

The optical communication monitoring device 14 provided in the node 3
0, it reaches node 3 from the transmission path of section # 2.
The multiplexed optical signal is demultiplexed by the demultiplexer 142.
It is output for each wavelength. Light split by the splitter 142
Signal (monitoring signal f_iIs superimposed on the main signal S_i) Is a light branch
Part 143_i, And each is divided into receivers 144 _iYou
And a modulator (not shown). Optical branching unit 143
_iFrom receiver 144_iReach the receiver 144
_iIs converted to an electrical signal by the
It is. Receiver 144_iMonitor the electrical signal output from
Signal restoration unit 145_iFrom the spreading code assigning unit 151
The spectrum is despread with the given spreading code PN2.
The monitoring signal f superimposed on this electric signal_iIs restored
Is output. Then, the monitoring signal restoring unit 145_iOr
Monitoring signal f output from_iIs the monitor signal detection circuit 146_iTo
More detected.

[0041] As described above, in this embodiment, which spread spectrum monitored signal f _i is superimposed on the main signal S _i is transmitted to the transmission line as an optical signal with a spread code in accordance with the transmission path, the The optical signal arriving at the next-stage node from the transmission path is spectrum-spread with a spreading code corresponding to the transmission path to restore the monitoring signal f _i , and further according to the transmission path reaching the next-stage node. The supervisory signal f _{i that} has been spectrum-spread by the new spreading code is superimposed and transmitted. Here, the spreading code corresponding to the transmission path is a code having a weak cross-correlation with respect to the auto-correlation (for example, an M-sequence code).
Is preferred. By doing so, it is only necessary to superimpose a new monitoring signal without removing the original monitoring signal. As described above, the replacement of the monitoring signal can be performed easily and inexpensively with the optical signal being used without being converted into the electric signal.

As to the method of spread spectrum of the monitor signal by the spread code, the monitor signal may be shifted (modulated) to the frequency f _i and then spread the spectrum, or the monitor signal may be spread spectrum in the baseband state. The frequency f _i may be shifted (up-conversion or down-conversion). Further, regarding a method of superimposing the monitoring signal on the main signal, an optical external modulator may be used,
The monitoring signal may be superimposed as an electric signal by photoelectric conversion. Furthermore, as for a method of superimposing a monitor signal at the time of wavelength conversion of an optical signal, an external optical modulator may be used, or a light source may be directly modulated.

(Second Embodiment) Next, a second embodiment of the optical communication monitoring method, the optical communication monitoring device and the optical communication monitoring system according to the present invention will be described. FIG. 2 is a diagram illustrating a configuration example of an optical communication monitoring device and an optical communication monitoring system according to the second embodiment. In this figure, three optical communication monitoring devices 100, 120 and 140A provided at the nodes of the network of the optical communication system, and
Two optical repeater amplifiers 200 and 210 provided in the middle of a section between nodes are shown. This embodiment is different from the first embodiment in the configuration of the optical communication monitoring device 140A provided in the node 3.

Optical communication monitoring device 14 provided in node 3
0A is the demultiplexer 142, the optical branching units 143 _{1 to} 143 ₃ , the receivers 144 _{1 to} 144 ₃ , and the monitoring signal restoring units 145 _{1 to} 145.
5 ₃ includes a monitoring signal detecting circuit 146 ₁ to 146 _3, spreading code assigning unit 151 and 153 and a selector 154. The optical communication monitoring device 140A is different from the optical communication monitoring device 140 in the first embodiment in that the optical communication monitoring device 140A further includes a spreading code assigning unit 153 and a selector 154.

The spreading code assigning section 151 has a section # 2
Generates a spread code PN2 corresponding to the transmission path of the above, and outputs the spread code PN2 to the selector 154. On the other hand, the spreading code adding section 153 generates a spreading code PN1 corresponding to the transmission path of section # 1, and uses the spreading code PN1 as the selector 1
Output to 54. The selector 154 is connected to the spreading code assigning unit 1.
51 and selects one of the spreading codes PN1 output from the spread code PN2 and spreading code imparting unit 153 which is output from, providing the monitoring signal restorer 145 _i. The monitor signal restoring section 145 _i performs spectrum despreading of the electric signal output from the receiving section 144 _i with the spreading code PN2 or PN1 given by the selector 154, and supervises the monitor signal f _i superimposed on this electric signal. Is restored and output. The monitoring signal detection circuit 146 _i detects the monitoring signal f _i output from the monitoring signal restoration unit 145 _i .

The optical communication monitoring method, the optical communication monitoring device, and the optical communication monitoring system according to the present embodiment operate in substantially the same manner as in the first embodiment. However, in the optical communication monitoring device 140A provided in the node 3, the multiplexed optical signal arriving at the node 3 from the transmission line of section # 2 is demultiplexed by the demultiplexer 142 and output for each wavelength. . The demultiplexer 142 demultiplexes the optical signal (monitor signal f _i is the main signal S _i which is superimposed) is split into two by the optical branching section 143 _i, each receiver 144 _i and the modulator (shown Is output to The optical signal reaching the receiver 144 _i from the optical branching section 143 _i is converted into an electric signal by the receiver 144 _i, the electric signal is output. The electric signal output from the receiver 144 _i is spectrum despread by the monitor signal restoration unit 145 _i with the spreading code PN 2 or PN 1 given by the selector 154, and the monitor signal f _i superimposed on this electric signal. Is restored and output.
The monitoring signal f _i output from the monitoring signal restorer 145 _i is detected by the monitoring signal detector circuit 146 _i.

In the present embodiment, in addition to the same effects as those of the first embodiment, the following effects are also obtained.
That is, whether the optical signal arriving at the node 3 is transmitted from the node 1 and arrives via the node 2, or is not the signal transmitted from the node 1 but arrives from the node 2 and arrives. Can be identified. That is, the selector 154 outputs the monitoring signal restoring unit 1
45 monitors signal when the spread code given to _i is PN1 f _i is detected is restored by the monitoring signal detecting circuit 146 _i by the monitoring signal restorer 145 _i, and the monitoring signal when the spreading code is PN2 f _i is the monitoring signal restoring unit 1
45 when it is restored is detected by the monitoring signal detector circuit 146 _i by _i, the optical signal having reached the node 3 is determined to be those that have reached through the node 2 is sent from node 1. On the other hand, when the spreading code provided from the selector 154 to the monitoring signal restoring unit 145 _i is PN 1, the monitoring signal f _i is not detected by the monitoring signal detection circuit 146 _{i, and} when the spreading code is PN 2, the monitoring signal is not detected. f
_{When i} is restored by the monitor signal restoration unit 145 _{i and} detected by the monitor signal detection circuit 146 _i , the optical signal arriving at the node 3 is not sent from the node 1 but sent from the node 2. It is determined that it has arrived. As described above, in the present embodiment, the transmission path of the optical signal can be traced.

(Third Embodiment) Next, a third embodiment of the optical communication monitoring method, the optical communication monitoring device and the optical communication monitoring system according to the present invention will be described. FIG. 3 is a diagram illustrating a configuration example of an optical communication monitoring device and an optical communication monitoring system according to the third embodiment. This figure shows two optical communication monitoring devices 100B and 120B provided at the nodes of the network of the optical communication system, and an optical repeater amplifier 200 provided in the middle of the section between the nodes.
It is shown. The present embodiment is different from the first embodiment in that the optical communication monitoring device provided in the node 3 is not shown, and the optical communication monitoring devices 100B and 120B provided in the nodes 1 and 2 are not shown. Is different.

Optical communication monitoring device 10 provided in node 1
0B is a main signal source 101 _{1 to} 101 ₃ , a monitor signal generation circuit 107 _{1 to} 107 ₃ , a spread spectrum unit 108 ₁ to 10
8 ₃ , transmitters 109 _{1 to} 109 ₄ , a multiplexer 110 </ b> B, and a spreading code assigning unit 112. This optical communication monitoring device 1
00B is the optical communication monitoring device 10 according to the first embodiment.
0, the transmitter 10 converts the spreading code PN1 output from the spreading code assigning unit 112 into an optical signal and outputs the optical signal.
9 ₄ further comprising point to, and multiplexer 110B are different in that also outputs multiplexes the optical signals output from the transmitter 109 _4.

The optical communication monitoring device 12 provided in the node 2
0B is a demultiplexer 122B, optical splitters 123 _{1 to} 123 ₃ ,
Receivers 124 _{1 to} 124 ₄ , monitor signal restoring units 125 ₁ to 1
25 ₃ , monitor signal detection circuits 126 _{1 to} 126 ₃ , monitor signal generation circuits 127 _{1 to} 127 ₃ , spread spectrum unit 128
_{1 to} 128 ₃ , modulators 129 _{1 to} 129 ₃ , multiplexer 130,
And spreading code assigning units 131B and 132. This optical communication monitoring device 120B is different from the optical communication monitoring device 120 in the first embodiment in that the duplexer 12
2B, except that it also demultiplexes an output optical signal from the transmitter 109 _4, receiver 124 ₄ further comprising a point of outputting the electric signal is converted into an electric signal by receiving the light signal, and , spreading code assigning unit 131B is a receiver 124 ₄
In that the spread code PN1 is output based on the electric signal output from the.

The optical communication monitoring method, the optical communication monitoring device, and the optical communication monitoring system according to the present embodiment operate in substantially the same manner as in the first embodiment. However, in the optical communication monitoring device 100B provided in the node 1, the spreading code attaching unit 11
Spreading codes PN1 output from 2 is converted into an optical signal by the transmitter 109 _4, the optical signal is transmitted to a transmission line sections # 1 through the multiplexer 110B. In the optical communication monitoring device 120B provided in the node 2, the optical signal is
The signal is received by the receiver 124 ₄ via the demultiplexer 122B and converted into an electric signal, and the spreading code PN1 is output by the spreading code assigning unit 131B based on the electric signal.

In the present embodiment, the following effects can be obtained in addition to the effects similar to those of the first embodiment.
That is, the spreading code PN1 generated in the node 1
Is transmitted to another node, the other node does not need to generate the spreading code PN1 by itself. Therefore,
The system configuration becomes simple.

(Fourth Embodiment) Next, a fourth embodiment of the optical communication monitoring method, the optical communication monitoring device and the optical communication monitoring system according to the present invention will be described. FIG. 4 is a diagram illustrating a configuration example of an optical communication monitoring device and an optical communication monitoring system according to a fourth embodiment. This figure shows two optical communication monitoring devices 100C and 120C provided at nodes of a network of an optical communication system, and an optical repeater amplifier 200 provided in the middle of a section between nodes.
It is shown. The present embodiment is different from the first embodiment in that the optical communication monitoring device provided in the node 3 is not shown, and the optical communication monitoring devices 100C and 120C provided in the nodes 1 and 2 are different. Is different.

The optical communication monitoring device 10 provided in the node 1
0C, the main signal source 101 _{1-101 3,} the monitoring signal generation circuit 107 ₁ to 107 _3, the spread spectrum unit 108 _1-10
8 ₃ , transmitters 109 _{1 to} 109 ₄ , a multiplexer 110C, a spreading code assigning unit 112, and a synchronization signal generating circuit 115. This optical communication monitoring device 100C is different from the optical communication monitoring device 100 according to the first embodiment in that it receives the spreading code PN1 output from the spreading code attaching section 112 and outputs the phase information of the spreading code PN1. further comprising a point generation circuit 115, the phase information output from the synchronizing signal generating circuit 115 further includes point a transmitter 109 ₄ for converting into an optical signal, and, multiplexer 110C from the transmitter 109 ₄ The difference is that the output optical signal is also multiplexed and output.

The optical communication monitoring device 12 provided in the node 2
0C is a demultiplexer 122C, optical splitters 123 _{1 to} 123 ₃ ,
Receivers 124 _{1 to} 124 ₄ , monitor signal restoring units 125 ₁ to 1
25 ₃ , monitor signal detection circuits 126 _{1 to} 126 ₃ , monitor signal generation circuits 127 _{1 to} 127 ₃ , spread spectrum unit 128
_{1 to} 128 ₃ , modulators 129 _{1 to} 129 ₃ , multiplexer 130,
It includes spreading code assigning units 131C and 132, and a synchronization signal detecting circuit 136. This optical communication monitoring device 12
0C is the optical communication monitoring device 120 according to the first embodiment.
Compared to, point duplexer 122C to be demultiplexed outputs an output optical signal from the transmitter 109 _4, the receiver outputs the electric signal is converted into an electric signal by receiving the light signal 124 ₄ , a synchronization signal detecting circuit 136 for detecting phase information based on the electric signal output from the receiver 124 ₄ , and
31C is different in that it outputs a spread code PN1 based on the phase information output from the synchronization signal detection circuit 136.

The optical communication monitoring method, the optical communication monitoring device, and the optical communication monitoring system according to the present embodiment operate in substantially the same manner as in the first embodiment. However, in the optical communication monitoring device 100C provided in the node 1, the spreading code
The spreading code PN1 output from the synchronization signal generation circuit 1
Phase information is input to 15 is output, the phase information output from the synchronizing signal generating circuit 115 is converted into an optical signal by the transmitter 109 _4, transmission path section # 1 that the optical signal through the multiplexer 110C Sent to In the optical communication monitoring device 120C provided in the node 2, the optical signal is received by receiver 124 ₄ via the demultiplexer 122C is an electrical signal, a phase signal by the synchronizing signal detection circuit 136 on the basis of the electrical signal Information is detected, and the spreading code PN1 is output by the spreading code providing unit 131C based on the phase information.

In the present embodiment, in addition to the same effects as those of the first embodiment, the following effects are also obtained.
That is, the spreading code PN1 generated in the node 1
Is transmitted to another node, and the other node can generate the spreading code PN1 based on the phase information. Therefore, the other node does not need to generate the spreading code PN1 by itself. Therefore, the system configuration is simplified.

(Fifth Embodiment) Next, a fifth embodiment of the optical communication monitoring system according to the present invention will be described.
FIG. 5 is a diagram illustrating a configuration example of an optical communication monitoring system according to a fifth embodiment. In this figure, the optical communication monitoring device 100 provided in the node 1, the optical communication monitoring device 120 provided in the node 2, the optical communication monitoring device 130 provided in the node 3, and the optical communication device provided in the node 4 are shown. A communication monitoring device 140 is shown. Node 1 and node 2
, Optical relay amplifiers 201 and 202 provided in the middle of section 300, and optical relay amplifier 21 provided in the middle of section 310 between node 2 and node 3.
0, optical repeater amplifiers 221 and 222 provided in the middle of section 320 between node 3 and node 4 and optical repeater amplifier 230 provided in the middle of section 330 between node 4 and node 1 It is shown. Also, a section is provided between the nodes 2 and 4. The optical communication monitoring device in FIG.
Any of those described in each of the fourth to fourth embodiments may be used.

The section 300 includes a spreading code P
N1 is assigned and the section 310 has a spreading code PN
2 are allocated, and the section 320 has a spreading code PN3
Is assigned to the section 330, and the spreading code PN4 is assigned to the section 330, and the spreading code PN is assigned to the section 340.
5 is allocated. In particular, if each spreading code is uniquely assigned to a section, it is suitable for replacement of a monitoring signal and tracing of a transmission path of an optical signal.

For example, at the node 3, the spreading code PN
If the supervisory signal is recovered and detected by both the PN1 and PN2, but the supervisory signal is not recovered or detected by any of the spreading codes PN3 to PN5, the optical signal arriving at the node 3 is transmitted from the node 1. Then, it can be determined that the data has arrived via the sections 300 and 310.

[0061]

As described in detail above, the optical communication monitoring method, the first optical communication monitoring device, and the second optical communication monitoring device according to the present invention.
According to the optical communication monitoring device, the monitoring signal is spread in the first node (first optical communication monitoring device) of the network with the spreading code corresponding to the transmission path to which the main signal is to be transmitted, and this spread spectrum is used. The main signal on which the supervised monitoring signal is superimposed is transmitted to the transmission line as an optical signal. At a second node (second optical communication monitoring device) of the network, the optical signal arriving via the transmission path is received and converted into an electric signal, and the electric signal is spectrum despread with a spread code to obtain the electric signal. Is restored, and the restored monitoring signal is detected. Further, a supervisory signal that has been spectrum-spread by a new spreading code according to the transmission path to the next-stage node is superimposed and transmitted. As described above, the replacement of the monitoring signal can be performed easily and inexpensively with the optical signal being used without being converted into the electric signal.

Further, when the second node (second optical communication monitoring device) sequentially performs spectrum despreading with a spreading code corresponding to each transmission path of the network, the monitoring signal is restored / decompressed by which spreading code. The transmission path of the optical signal that has reached the second node can be traced based on the detection. In particular, spreading codes specific to sections between nodes of the network are preferred for tracing the transmission path.

In the first node (first optical communication monitoring device), a spread code used for spread spectrum is transmitted as an optical signal to the optical transmission line, and the second node (second optical communication monitoring device). (Monitoring device) receives the spread signal arriving as an optical signal and performs spectrum despreading with the received spread code, the spread code generated in the first node is transmitted to the second node. Therefore, it is not necessary for the second node to generate the spreading code by itself, thus simplifying the system configuration.

In the first node (first optical communication monitoring device), phase information of a spread code used in spread spectrum is transmitted as an optical signal to an optical transmission line, and
When the node (second optical communication monitoring device) receives the phase information arriving as an optical signal and performs spectrum despreading with a spreading code based on the received phase information, the signal is generated in the first node. The phase information of the spread code is transmitted to a second node, and the second node can generate a spread code based on the phase information.
The second node does not require a circuit for synchronization supplementation or synchronization tracking, and therefore, has a simple system configuration.

Further, in the optical communication monitoring system according to the present invention, since the above-mentioned optical communication monitoring device is provided at each node of the network, the monitoring signal can be replaced with the optical signal without converting it into an electric signal. It can be performed cheaply and easily.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of an optical communication monitoring device and an optical communication monitoring system according to a first embodiment.

FIG. 2 is a diagram illustrating a configuration example of an optical communication monitoring device and an optical communication monitoring system according to a second embodiment.

FIG. 3 is a diagram illustrating a configuration example of an optical communication monitoring device and an optical communication monitoring system according to a third embodiment.

FIG. 4 is a diagram illustrating a configuration example of an optical communication monitoring device and an optical communication monitoring system according to a fourth embodiment.

FIG. 5 is a diagram illustrating a configuration example of an optical communication monitoring system according to a fifth embodiment.

FIG. 6 is a diagram illustrating a configuration example of a conventional optical communication monitoring device and a conventional optical communication monitoring system.

[Explanation of symbols]

100 optical wavelength multiplexing communication monitoring apparatus, 101 _{1 to} 101 ₃ ...
Main signal source, 107 _{1 to} 107 ₃ ... monitoring signal generation circuit, 10
8 _{1-108 3} ... spread spectrum unit, 109 ₁ to 109 ₄
... transmitters, 110, 110B, 110C ... multiplexers, 11
2 ... Spreading code assigning unit, 115 ... Synchronous signal generation circuit, 12
0: Optical wavelength division multiplexing communication monitoring device, 122, 122B, 12
2C: duplexer, 123 _{1 to} 123 ₃ ... optical branching unit, 124 ₁
... 124 ₄ ... receiver, 125 ₁ -125 ₃ ... monitor signal restoring unit, 126 ₁ -126 ₃ ... monitor signal detecting circuit, 127 _1-
127 ₃ ... monitoring signal generating circuit, 128 _{1 to} 128 ₃ ... spread spectrum unit, 129 _{1 to} 129 ₃ ... modulator, 130 ...
Multiplexers, 131, 131B, 131C, 132 ... spreading code assigning units, 136 ... synchronous signal detection circuits, 140, 140
A: optical wavelength division multiplexing communication monitoring device, 142: duplexer, 143
_{1 to} 143 ₃ ... optical branching unit, 144 _{1 to} 144 ₃ ... receiver, 1
45 _{1 to} 145 ₃ ... monitoring signal restoration unit, 146 _{1 to} 146 ₃ ...
Monitor signal detection circuit, 151, 153...
154: selector, 200, 210: optical repeater amplifier.

Continued on the front page F term (reference) 5K002 AA01 AA03 AA06 BA05 DA02 EA06 FA01 GA03 5K022 EE02 EE21 EE31 5K042 AA01 AA08 BA02 CA10 CA11 CA12 CA15 CA16 DA32 EA04 EA06 FA21 FA22 FA25 LA11 MA01

Claims (14)

[Claims] An optical communication monitoring method for superimposing a monitoring signal for network monitoring on each main signal to form an optical signal, transmitting the optical signal to a transmission line of the network, and monitoring the network with the monitoring signal. Wherein, at a first node of the network, the monitor signal is spectrum-spread with a spreading code corresponding to a transmission path to which the main signal is to be transmitted, and the spectrum-spread monitor signal is superimposed on the main signal. An optical signal is transmitted to the transmission line. At a second node of the network, the optical signal arriving via the transmission line is received and converted into an electric signal. An optical communication monitoring method, comprising: restoring a monitoring signal superimposed on an electric signal, and detecting the restored monitoring signal. 2. The optical communication monitoring method according to claim 1, wherein the second node sequentially performs spectrum despreading with a spreading code corresponding to each transmission path of the network. 3. The optical communication monitoring method according to claim 1, wherein the spreading code is specific to a section between nodes of the network. 4. The first node sends a spread code used for spread spectrum as an optical signal to the optical transmission line, and the second node receives a spread signal arriving as an optical signal. The optical communication monitoring method according to claim 1, wherein spectrum despreading is performed with the received spread code. 5. The first node sends out phase information of a spread code used in spread spectrum as an optical signal to the optical transmission line, and at the second node, phase information arriving as an optical signal. 2. The optical communication monitoring method according to claim 1, further comprising: receiving a received signal, and performing spectrum despreading with a spreading code based on the received phase information. 6. An optical communication monitoring device that superimposes a monitoring signal for network monitoring on each of the main signals to generate an optical signal, transmits the optical signal to a transmission line of the network, and monitors the network based on the monitoring signal. A spread spectrum means for spectrum-spreading the monitor signal with a spread code corresponding to a transmission path to which the main signal is to be transmitted; and a light in which a monitor signal spread by the spectrum spread means is superimposed on the main signal. Transmitting means for transmitting a signal to the transmission line; and first means for providing the spread code to the spectrum spread means.
An optical communication monitoring device, comprising: 7. An optical communication monitoring device that superimposes a monitoring signal for network monitoring on each of the main signals to generate an optical signal, transmits the optical signal to a transmission line of the network, and monitors the network based on the monitoring signal. Receiving means for receiving an optical signal arriving via a transmission path, converting the signal into an electric signal, outputting the electric signal, and performing spectrum despreading of the electric signal output from the receiving means with a spreading code. Monitoring signal restoring means for restoring a monitoring signal superimposed on the electric signal; monitoring signal detecting means for detecting a monitoring signal restored by the monitoring signal restoring means; and spreading the spreading code to the monitoring signal restoring means. And a second spreading code providing means. 8. The optical communication system according to claim 7, wherein said second spreading code assigning means sequentially gives a spreading code corresponding to each transmission path of said network to said monitor signal restoring means. Monitoring device. 9. The optical communication monitoring device according to claim 6, wherein the spreading code is unique to a section between nodes of the network. 10. The apparatus according to claim 6, further comprising a spread code transmitting means for transmitting a spread code given to said spectrum spread means by said first spread code providing means to said optical transmission line as an optical signal. Optical communication monitoring equipment. 11. A spread code receiving means for receiving a spread signal arriving as an optical signal, wherein said second spread code providing means converts said spread code received by said spread code receiving means to said monitor signal restoring means. The optical communication monitoring device according to claim 7, wherein: 12. A spread code phase information transmitting means for transmitting phase information of a spread code provided to said spread spectrum means by said first spread code applying means to said optical transmission path as an optical signal. The optical communication monitoring device according to claim 6. 13. A spread code phase information receiving means for receiving phase information of a spread signal arriving as an optical signal, wherein said second spread code providing means includes a phase code received by said spread code phase information receiving means. The optical communication monitoring device according to claim 7, wherein a spreading code is provided to the monitoring signal restoring means based on the information. 14. An optical communication monitoring system that superimposes a monitoring signal for network monitoring on each main signal to form an optical signal, transmits the optical signal to a transmission line of the network, and monitors the network with the monitoring signal. And each node of the network is provided with one of the claims 6 to 13.
An optical communication monitoring system, comprising: the optical communication monitoring device according to the item.