JPH1155700A - Wavelength light adm device, optical signal fault monitor system using the device and ring network - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the hardware amount per a transmission optical signal speed, to reduce the cost and to make the scale of the system small. SOLUTION: An optical branching device 11 branches a wavelength multiplex light for each wavelength, an optical branch 2n receiving the branched light for each wavelength branches the light to an optical gate switch 3n and an optical receiver 5n, which connects to an optical signal fault monitor means 80. In the case the optical signal fault monitor means 80 detects a wavelength deviation signal OLOW, a signal interrupt signal OLOS or an S/N deterioration signal OSD as a fault detection signal in an optical layer from a light of a wavelength processed by the optical branch 2n, a control means 70 controls an optical gate switch 3n to interrupt passing of the optical signal to send a network fault detection signal AIS-O to a down-stream. Thus, in the case of detecting an optical no signal at the optical receiver 5n, the optical signal fault, monitor means 80 recognizes the signal AIS from an upper stream and eliminates the need for any special hardware.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical communication, optical switching,
Wavelength optical ADM (Add-Drop Mul) in optical networks
The present invention relates to a device, and a fault monitoring method and a network using the device, and more particularly to a wavelength light A that realizes low cost and small size as a node of the network.
It relates to a DM device.

[0002]

2. Description of the Related Art Conventionally, as an optical network, TDM
SONET (Synchronous Op) using (Time Division Multiplexing)
tical Network) / SDH (Synchronous Digital Hierar)
chy) is the mainstream.
In a network based on SONET / SDH, transmission path switching is generally performed by terminating an optical signal in a line layer, performing switching, and then multiplexing the optical signal again.

[0003] At this time, in order to ensure the reliability of link connection, the presence or absence of an optical signal, for example, GR-253-CORE (Issue 1, described in the Bellcore (Bell Communications Research) standard).
As described in December 1994), detecting no signal (hereinafter, LOS: Loss of Signal) or section overhead in a frame (hereinafter, referred to as LOS).
By evaluating SOH: Section Overhead or Line Overhead (hereinafter, LOH: Line Overhead), frame loss (hereinafter, LOF: Loss Of Frame), pointer loss (hereinafter, LOP: Loss of Pointer), code error rate (hereinafter, error rate) , BER: Bit Error Rate) and the like.

In recent years, an OADM capable of switching a transmission path in the form of light without electrically terminating an optical signal.
(Optical Add-Drop Multiplex) device has been proposed and its introduction into the system is being considered. SONE
One of the network elements of T, DCS (Digi
tal Cross-Connect System) includes optical / electrical conversion (hereinafter, O / E conversion), demultiplexer (hereinafter, DEMUX: Demultiplexer), switching,
Multiplexer (hereinafter MUX: Multiplexer)
While optical conversion (hereinafter referred to as E / O conversion) is performed, OADM devices only need to perform switching, and DEMUX and MUX of electrical signals are unnecessary, so that the amount of hardware per transmission optical signal speed can be reduced. In addition, cost reduction and system miniaturization can be expected.

[0005]

When a failure occurs in a network in which an OADM device is arranged, an OAD
The M device is required to detect and determine a failure such as signal light interruption due to a cut of an optical fiber or the like and signal light quality deterioration due to a failure of an optical repeater amplifier and to perform recovery according to the type of the failure. SONET / SD currently used
When network faults are detected using the frame overhead of the H standard, sections or lines need to be terminated in the OADM device.

When a failure occurs in a line including an OADM device, the occurrence of the failure is notified to an end user who uses the line.
AIS: Alarm Indication Signal) read processing and write processing are required. However, in an OADM apparatus that handles optical signals multiplexed at high density, when obtaining network fault information from the frame overhead of a transmitted optical signal, not only large-scale hardware is required, but also fault monitoring information in the network. However, there is a problem that it is necessary to electrically terminate the multiplexed optical signal, read the frame overhead, and multiplex the optical signal again to read only the optical signal.

In order to introduce an OADM device into an existing optical network, a time-division-oriented SONET is required.
The optical layer is defined as an optical layer that treats an optical signal and performs electrical processing in a time-synchronous manner and obtains or does not add information from the optical signal in distinction from the / SDH layer. / SDH provides an automatic protection system (hereinafter referred to as APS: Automatic Protection System), which is a network failure recovery means.
It is necessary to prevent contention with the protection system in the optical layer newly supplied by the ADM device.

[0008] That is, even if SONET / SDH will disappear from the ideal form of the optical network in the future, since at present the SONET / SDH is widely spread worldwide, its assets will be used for at least for the time being. Since it is difficult to immediately shift from the APS to the protection system using the OADM device in terms of cost, at least for the time being, it is necessary to make the protection in the optical layer using the OADM device coexist with the APS. Because.

[0009] Considering the introduction into an actual network, the OADM device has the high potential that the amount of hardware per transmitted optical signal can be reduced because of the above-mentioned problems. It cannot be fully demonstrated. In order for the OADM device to fully demonstrate its capabilities, a network fault monitoring and fault recovery method for a network handling high-density multiplexed signals while maintaining compatibility with SONET / SDH, and a method for the same. It is essential to develop hardware.

An object of the present invention is to realize a wavelength optical ADM apparatus capable of dropping and adding signal light of an arbitrary wavelength in a node and competing with a SONET / SDH APS or another framing format transmission apparatus. Not wavelength
An object of the present invention is to define an optical signal interruption failure detection signal in a spatial multiplexing-oriented optical layer, and to realize a reduction in cost and size of an optical ADM device node.

[0011]

A first wavelength optical ADM apparatus according to the present invention comprises: an optical demultiplexer for demultiplexing wavelength multiplexed light input from one optical transmission line into a plurality of wavelengths; A plurality of optical receivers connected to one optical output for each of a plurality of wavelengths of the optical demultiplexer, and one optical output of the demultiplexer input to each of the optical receivers is connected to pass light. And a plurality of optical gate switches for controlling the cutoff, a plurality of optical transmitters corresponding to each of the optical receivers and having one optical output constituting the wavelength multiplexed light, the optical output of the optical gate switch and the light An optical multiplexer connected to the optical output of the transmitter and outputting wavelength-division multiplexed light to the other optical transmission line.

Further, the second wavelength optical ADM apparatus is connected to a circulator for inputting wavelength multiplexed light from one optical transmission line and outputting wavelength multiplexed light to the other optical transmission line. An optical multiplexer / demultiplexer that outputs a plurality of lights obtained by demultiplexing input wavelength multiplexed light for each wavelength, and that inputs and wavelength-multiplexes a plurality of demultiplexed lights and outputs the input / output of the optical circulator. And a first optical branch that is connected to the optical multiplexer / demultiplexer to input and output each of the lights separated for each wavelength, and to split each of the input and output lights separated for each wavelength. An optical receiver for connecting one optical output of the first optical branch, an optical transmitter corresponding to each optical receiver and having one optical output constituting the wavelength multiplexed light, and a demultiplexer. Light transmission corresponding to each of the And an optical gate switch for controlling the cutoff, corresponding to each of the plurality of split lights, connected to the optical input / output of each of the first optical branches, and connected to one of the optical gate switches on the other hand. Input and output light,
A second light branch for inputting light from the optical transmitter; and a light reflection mirror corresponding to each of the plurality of demultiplexed lights and connected to the other of the optical gate switches. The wavelength multiplexed light output from the output and received by the optical multiplexer / demultiplexer is output from the optical multiplexer / demultiplexer to the optical input / output of the optical circulator from the optical output of the optical circulator to the optical transmission line. Has been output.

A third wavelength optical ADM device separates the wavelength-division multiplexed light input from the optical transmission line into each wavelength, and multiplexes the demultiplexed light into wavelengths. Optical multiplexer / demultiplexer, and on the other hand, each connected to this optical multiplexer / demultiplexer to input / output the light separated for each wavelength, and, on the other hand, to input / output the separated light for each wavelength. 1st branch
, An optical receiver for connecting each one of the optical outputs of the first optical branch, and an optical transmitter having one of the optical outputs corresponding to each of the optical receivers and constituting the wavelength multiplexed light. And an optical gate switch corresponding to each of the plurality of demultiplexed lights and controlling passage and blocking of light, and passing only a corresponding optical output of the optical gate switch corresponding to each of the plurality of demultiplexed lights. An optical isolator, corresponding to each of a plurality of demultiplexed lights, connected to the optical input / output of each of the first optical splitters on the one hand, and optically splitting the light separated for each input / output wavelength on the other hand. And a second optical branch for inputting light from the optical transmitter, corresponding to each of a plurality of demultiplexed lights, and connected to the optical input / output of each of the second optical branches, and the other When receiving the optical output of the optical isolator, A third optical branch for outputting light of a different wavelength from the optical output to the optical gate switch, wherein each of the lights separated for each wavelength is separated by the optical multiplexer / demultiplexer and the first optical branch. After passing through the second optical branch, the third optical branch, the optical gate switch, and the optical isolator, the third optical branch and the second optical branch for the separated adjacent wavelengths are formed. The light returns to the optical multiplexer / demultiplexer via the optical multiplexer / demultiplexer, and the optical multiplexer / demultiplexer wavelength-multiplexes the light and outputs the light.

In the fourth wavelength optical ADM apparatus, the optical gate switch is used as a gate, and the ON / OFF state of the gate, the presence or absence of an optical signal input to the optical receiver, and the output from the optical transmitter Control means for selectively switching between the presence and absence of an optical signal to be transmitted and selecting any one of passage, branching, and insertion of the optical signal, and light intensity within a wavelength band of a predetermined width including at least the signal light. Determining the presence or absence of the signal light by calculating an optical S / N ratio from a ratio of the intensity of the spontaneous emission light in a wavelength range different from the wavelength range having the same width as the wavelength range; and The presence or absence of the signal light is determined from the light intensity within a wavelength range of a certain width including the signal light, so that the optical signal cutoff signal (OLO
S) and detecting the optical signal wavelength shift signal (OLOW) by monitoring the wavelength shift of the signal light from the light intensity within the wavelength range to monitor the interruption failure of the optical signal. The light S is determined from the ratio between the function to be performed and the intensity of the spontaneous emission light in a wavelength range having a width equal to the wavelength range and different from the wavelength range, which is at least equal to the wavelength range including the signal light. / N ratio is calculated and the light S / N ratio is calculated.
A function of detecting an optical S / N ratio decrease signal (OSD) when the ratio falls below a predetermined threshold value.
An optical signal failure monitoring means for detecting at least one of the OS, the OLOW, and the OSD as a failure detection signal, and detecting at least one of the failure detection signals, wherein the optical signal failure monitoring means includes at least one of the failure detection signals. Is detected,
Upon receiving these detection signals, the control means controls the gate to cut off the signal light from the output corresponding to the detected input, thereby converting the detected failure detection signal to a network failure detection signal in the optical layer. (AIS-
O).

Next, in a first optical signal failure monitoring system using the above wavelength optical ADM apparatus according to the present invention, an optical ADM apparatus and an optical repeater each have the function of the above wavelength optical ADM apparatus according to the present invention, An optical network comprising the optical ADM apparatus, the optical repeater amplifier, and a line terminator for terminating an optical signal, and handling an optical signal wavelength-multiplexed by at least one wavelength in one optical fiber. Signal failure monitoring means is provided as an optical layer monitoring device.

In the second optical signal failure monitoring method, when the wavelength optical ADM device detects at least one of the failure detection signals, the control means inputs the detected failure detection signal to the input. A function of converting the failure detection signal into a network failure detection signal (AIS-O) in the optical layer by blocking the signal light from the corresponding output. With this AIS-O conversion function, no information is obtained because the electrical signal obtained by electrically terminating an optical signal wavelength-multiplexed by at least one wavelength in a time-synchronized manner does not include signal information. Further, since no new information is added, the processing is simplified.

In the third optical signal fault monitoring system, each of the optical ADM device and the optical repeater amplifier has at least the optical layer monitor device mounted thereon, and is connected to the optical ADM device, the optical repeater amplifier, and the optical layer. An optical network for handling an optical signal wavelength-multiplexed with at least one wavelength in one optical fiber, wherein the optical layer monitor device comprises an OLOS in the optical layer in the optical network. And AI
At least one of the SOs monitors an optical signal interruption fault in the network.

Further, in the optical signal failure monitoring system of the optical network using one of the optical ADM apparatus and the optical repeater amplifier, the OLOS of the network failure in the optical layer is converted into the AIS-O and converted. Notifying a transmission device connected to a layer other than the optical layer of a network failure from the optical layer, and transmitting the OLS of the network failure in the optical layer to the AIS-
The information is converted to O, and a network failure is notified from the optical layer to a transmission device connected to a layer other than the optical layer.

Further, in the failure recovery processing of the optical signal failure monitoring method, a signal for notifying the occurrence of a failure in a transmission device connected to the optical layer using one of the optical ADM device and the optical repeater amplifier is used. When monitoring a failure of an optical network using the OLOS and the AIS-O in the optical layer, the signal regenerator is arranged upstream of a network failure detection position of the optical ADM device in the optical network. In this case, one is a transmission device standard connected to at least one or more optical layers between the optical ADM device and the signal regeneration repeater of the transmission device standard connected to the optical layer. By arranging a line terminator, the signal regenerator repeats the signal from the signal regenerator to the downstream optical path when a network fault is detected. The line termination unit of the transmission device standard connected to the network device recognizes the monitoring signal issued by the signal regeneration repeater to notify the line termination unit of the occurrence of the network failure to the line termination unit to recover the network failure. Another one is to provide the signal regeneration repeater with the AIS-O issuing function in the optical layer, and to provide at least one of the optical repeater amplifier and the optical ADM device downstream of the signal regeneration repeater. By notifying the network failure, the optical AD
Recovery of the network failure by the optical path switching performed by the M device, and conversion of the OLOS of the network failure in the optical layer into the AIS-O to cause a network failure in the transmission device connected from the optical layer to the optical layer. And recovery of the network failure by the transmission device connected to the optical layer. Further, in the optical network, network management information is allocated to a wavelength region different from the main signal light wavelength region, and network information communication is performed between nodes by the optical ADM device and between nodes between the optical ADM device and the line terminator. It is carried out.

By these means, it is possible to perform fault monitoring, fault notification, and network information communication without depending on the framing format of the transmission device connected to the optical layer.

In the fourth optical signal fault monitoring system, each of the optical ADM device and the optical repeater amplifier has at least the optical layer monitor device, and the optical ADM device, the optical repeater amplifier, and the SONET / SDH standard. An optical network including a line terminator for handling an optical signal wavelength-multiplexed by at least one wavelength in one optical fiber, wherein the SONET / S
When a network fault is detected in the section layer of the DH, a network fault detection signal (AIS-AIS-A) is assigned to the line overhead to notify the line terminator downstream of the network fault detection position of the occurrence of the network fault. L) reads the AIS-L to recognize the network failure and outputs the SIS again to the line termination to notify the network termination to the line termination.
Instead of the AIS-L in the ONET / SDH layer, the OLOS and the A in the optical layer
At least one of the IS-Os monitors an optical signal interruption fault in the network.

When a network failure occurs in an optical layer in an optical network using one of the optical ADM apparatus and the optical repeater described above, OLOS is converted into AIS-O to convert the line termination into the line terminator. LOS is intentionally detected, and the SON is
A network failure can be notified to the ET / SDH layer.

Further, in the failure recovery function in the fifth optical signal failure monitoring method, an OL in the optical layer is used instead of the AIS-L in the SONET / SDH layer by using one of the optical ADM apparatus and the optical repeater amplifier.
In an optical network for monitoring a network failure using at least one of an OS and an AIS-O, the SONET / SDH standard signal regenerator is arranged upstream of a network failure detection position of the optical ADM apparatus. In this case, by arranging at least one SONET / SDH standard line terminator between the optical ADM apparatus and the signal regenerative repeater, the signal regenerative repeater can detect a network failure from the signal regenerative repeater. The line termination unit recognizes the AIS-L issued by the signal regeneration repeater to notify the downstream line termination unit of the SONET / SDH standard of the occurrence of the network failure, and causes the line termination unit to recognize the APS of the SONET / SDH standard.
(Automatic Protection System) is activated to recover from the network failure.

Further, as another failure recovery function, when a signal regenerative repeater is disposed upstream of a network fault detection position of the optical ADM apparatus, the signal regenerative repeater is provided in the signal regenerative repeater in the optical layer. Providing an O issue function to notify any of the optical repeater amplifier and the optical ADM device downstream of the signal regenerative repeater and the optical ADM device of the network failure, thereby performing optical path switching performed by the optical ADM device in the optical layer. Recovery from the network failure and the network failure in the optical layer from the OLOS to the AIS-O, and the LOS (Loss of Loss) is intentionally transmitted to the line termination.
Signal), the SONET / SDH APS performed by notifying the SONET / SDH layer of a network failure from the optical layer.
(Automatic Protection System) to recover from the network failure.

Further, in the network information communication between nodes in the sixth optical signal failure monitoring system, the optical ADM
In an optical network that uses one of the device and the optical repeater amplifier and monitors a network fault using at least one of the OLOS and the AIS-O in the optical layer instead of the AIS-L in the SONET / SDH layer, This is performed between the optical ADM devices that form nodes by allocating network management information to a wavelength region different from the signal light wavelength region, and between nodes between the optical ADM device and the line terminator.

Finally, in a ring network according to the present invention, at least one wavelength optical ADM device equipped with the above optical layer monitor device is connected in a ring network by at least one transmission line.
A failure is detected using at least one of the OS and the AIS-O, a failure is recovered by switching to a spare transmission path and at least one of network reconfigurations.

[0027]

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

FIG. 1 is a functional block diagram showing an embodiment of the present invention. Wavelength optical ADM device 1 shown in FIG.
Reference numeral 00 designates a node. In this node, an optical demultiplexer 1 is used to add and drop a signal of wavelength multiplexed light for each wavelength.
1, optical multiplexer 12, optical branches 21 to 2n, optical gate switches 31 to 3n, optical branches 41 to 4n, optical receivers 51 to 5
n, optical transmitters 61 to 6n, control means 70, and optical signal failure monitoring means 80.

It is assumed that each of the optical demultiplexer 11 and the optical demultiplexer 12 uses an optical demultiplexer or an optical demultiplexer typified by an arrayed waveguide diffraction grating.

The optical branches 21 to 2n are provided for each wavelength obtained by splitting the input wavelength multiplexed light by the optical splitter 11.
It is assumed that the input light is output to each of the optical gate switches 31 to 3n and each of the optical receivers 51 to 5n.

As the optical gate switches 31 to 3n, gate switches having a large on / off ratio are used for switching between branching and insertion, and the EDFA (erbium-doped fiber array) gate switch 30 schematically shown in FIG. I do.

The optical branches 41 to 4n are connected to the optical gate switch 3
1 to 3n and the optical transmitters 61 to 6n
It is assumed that each output is input and output to the optical multiplexer 12.

Optical receivers 51-5n and optical transmitters 61-n
6n, under the control of the control means 70, transmit and receive a predetermined optical signal.

The control means 70 controls the wavelength ADM device 100
, And based on the optical signal interruption monitoring signal received from the optical signal failure monitoring means 80, the target optical gate switch 3n is turned off to interrupt the transmission of the optical signal sent downstream, etc. Each component is controlled so as to realize the following functional operation.

The optical signal failure monitoring means 80 includes the optical receiver 51
5n are monitored, and the result is notified to the control means 70 by a predetermined signal. A specific example of the fault monitoring will be described later with reference to FIG.

Next, the EDFA gate switch 30 will be described with reference to FIG.

EDFA gate switch 3 shown in FIG.
0 is the excitation light source 131, WDM (Wavelength Division)
Multiplex: for wavelength multiplexing) coupler 132 and EDF
(Erbium-doped fiber) 133, and the signal light is input to the EDF 133 from the optical transmission line.
The pump light output from the pump light source 131 is input to the EDF 3 via the wavelength multiplexing coupler 132. In the EDFA gate switch 30, the on / off of the switch and the light level adjustment can be performed on the output signal light by controlling the excitation light intensity of the excitation light source 131.

In the wavelength optical ADM apparatus 100 shown in FIG. 1, the monitoring of the main signal in the optical layer is the information monitoring on the wavelength axis, and the monitoring of the SONET / SDH in units of frames, that is, the information monitoring on the time axis is supported. By doing so, it is possible to handle high-speed optical signals of the Gb / s class.

Next, with reference to FIG. 3, a description will be given of the optical signal interruption failure monitoring signal generated by the optical signal failure monitoring means 80 in FIG. Figure 3 shows the optical layer and SONET / S
It is a target figure which shows and compares the network fault monitoring item in a DH layer.

That is, in the network fault monitoring item in the SONET / SDH layer, a frame loss (LOF: Loss o) for monitoring a time synchronization failure.
f Frame) or pointer loss (LOP: Loss of Poin)
ter), no signal (LOS: Loss o
f Signal) and a bit error rate (BER: Bit Error Rate) for monitoring signal quality deterioration failure.

On the other hand, in the optical layer of the present invention, the wavelength shift signal of the optical signal for monitoring the wavelength shift error of the signal light by the combination of the optical band pass filter (BPF) and the optical S / N ratio or the optical intensity monitoring. (OLOW: Opti
Cal Loss of Wavelength), optical signal interruption signal (OLOS: Optical Loss of Signal) for detecting optical signal interruption failure using monitoring of optical intensity or optical S / N ratio, and optical signal quality by optical S / N monitoring Optical S / N ratio decrease signal (OSD: Optical Signal Degrade) for monitoring deterioration failure
Each of them is newly defined, and the optical signal failure monitoring means 80 in FIG. 1 monitors the optical signal interruption failure in the network.

When a fault occurs in a certain line in the network, the SO is required to notify the fault to the downstream.
In NET / SDH, a line failure detection signal (AIS-L:
LineAlarm Indication Signal).

On the other hand, in the optical layer according to the present invention, the network element detecting the above-mentioned OLOW, OLOS, and OSD, that is, the control means 7 in FIG.
0 and the optical signal failure monitoring means 80 interrupts the optical output to notify the occurrence of a failure by a network failure detection signal (AIS-O: Optical Alarm Indication System).
gnal) to the downstream. That is, when the network element shuts off the optical output, the network element downstream therefrom transmits the OLOS to the AIS.
It is detected as -O and the light output is cut off.

As described above, finally, the SONET / S
The DH line terminator detects the LOS, and this detection allows the optical layer to notify the SONET / SDH layer of a network failure. This series of AIS propagation is equivalent to a network element that detects OLOS, OLOW, or OSD converting it to AIS-O in the optical layer and reporting it to the line terminator in the SONET / SDH layer. .

The recovery from the failure can be performed by switching the protection switch of each node by receiving the above-mentioned optical signal cutoff monitoring signal. Since the above can be realized with a simple hardware configuration, it is advantageous for reducing the size and cost of the system.

[0046]

Next, an embodiment of the present invention will be described based on the above embodiment.
A gate switch, and the code value “n” is a value “4”, and the wavelengths are 1548 nm (λ 1) and 1550 nm (λ
2) It is assumed that four signal lights of 1552 nm (λ3) and 1554 nm (λ4) are wavelength-multiplexed.

Next, a first embodiment of the present invention will be described with reference to FIG.
This will be described in detail with reference to FIG.

The components and connection configuration for this embodiment have already been described with reference to FIG.

Wavelength 1548 nm (λ1), 1550 nm
The four signal lights of (λ2), 1552 nm (λ3), and 1554 nm (λ4) are input to an optical demultiplexer 11 represented by an arrayed waveguide diffraction grating, and different optical branches 21 to 24, respectively.
Is output to That is, only one wavelength of light is input to each of the optical branches 21 to 24.

Next, passage, branching, and insertion of an optical signal in the operation of the wavelength ADM apparatus 100 will be described.

First, the operation of passing an optical signal will be described. The wavelength 154 input from the optical demultiplexer 11 to the optical branch 21
After passing through the EDFA gate 31, the signal light of 8 nm (λ 1) is input to the optical multiplexer 12 typified by the arrayed waveguide diffraction grating via the optical branch 41.

Next, the branching operation of the optical signal will be described. The wavelength 154 input from the optical demultiplexer 11 to the optical branch 21
The signal light of 8 nm (λ1) passes through the optical branch 21 to the EDFA.
The signal is output to the gate 31 and a part is input to the optical receiver 51 and received.

Finally, the operation of inserting an optical signal will be described. The wavelength 154 input from the optical demultiplexer 11 to the optical branch 21
The signal light of 8 nm (λ 1) emits E
When the optical gate switch 31 of the DFA gate is turned off, the output to the optical branch 41 is cut off. At this time, the signal light having a wavelength of 1548 nm (λ1) output from the optical transmitter 61 under the control of the control means 70 is input to the optical multiplexer 12 by the optical branch 41.

For each of the other wavelengths λ 2 to λ 4, the flowing optical transmission path is changed from the optical demultiplexer 11 to the optical multiplexer 12.
Up to this point, it has the same configuration. Therefore, it is possible to add and drop an optical signal having an arbitrary wavelength in the node.

Next, a second embodiment of the present invention will be described with reference to FIG.

The wavelength optical ADM apparatus 200 shown in FIG.
Are optical splitter / demultiplexer 211, optical splitters 221 to 224, optical splitters 231 to 234, EDFA gates 241 to 244, optical receivers 251 to 254, optical transmitters 261 to 264, control means 270, circulator 280, and optical It is assumed that it is constituted by reflection mirrors 281 to 284.

The second embodiment is different from the first embodiment in that wavelength-multiplexed input light passes through a circulator 280 and is input to an optical multiplexer / demultiplexer 211, while an optical multiplexer / demultiplexer 2
11 is output through the circulator 280. The signal light demultiplexed for each wavelength by the optical demultiplexer 211 is reflected by the light reflection mirrors 281 to 284. Reflected by the optical multiplexer / demultiplexer 211
It is to return to.

The signal light input to the wavelength ADM apparatus 200 has wavelengths of 1548 nm (λ1), 1550 nm (λ2),
Four wavelengths of 552 nm (λ3) and 1554 nm (λ4) are multiplexed, and these lights pass through an optical circulator 280 and are input to an optical multiplexer / demultiplexer 211 represented by an arrayed waveguide diffraction grating. Is done.

The optical demultiplexer / demultiplexer 211 demultiplexes the received light and outputs it to different optical branches 221 to 224.
The light received from the light branches 221 to 224 is multiplexed and output to the optical circulator 280. Therefore, optical branch 2
Each of 21 to 224 has only one wavelength of light.

The optical branch 221 outputs the light having a wavelength of 1548 nm (λ 1) received from the optical multiplexer / demultiplexer 211 to the optical branch 231 and the optical receiver 251, respectively.
Is transmitted to the optical multiplexer / demultiplexer 211.

The optical branch 231 outputs the light having the wavelength of 1548 nm (λ 1) received from the optical branch 221 to the EDFA gate 241, and outputs the light received from the EDFA gate 241 and the optical transmitter 261 to the optical branch 221.

The EDFA gate 241 is located between the light branch 231 and the light reflection mirror 281 and under the control of the control means 270, the wavelength of 1548 nm received from the light branch 231.
When passing the light of (λ1), the light is sent to the light reflection mirror 281, and the reflected light is output to the light branch 231.

The components for other wavelengths are connected in the same manner.

Next, passing, dropping, and insertion of signal light in the operation of the wavelength optical ADM apparatus 200 will be described.

The wavelength 15 output from the optical multiplexer / demultiplexer 211
After the signal light of 48 nm (λ1) passes through the EDFA gate 241, it is reflected by the light reflection mirror 281 and the EDF
After passing through the A gate 241 again, it is again input to the optical multiplexer / demultiplexer 211 and passes therethrough. The signal light having a wavelength of 1548 nm (λ1) output from the optical demultiplexer / demultiplexer 211 is
After a part is output to the optical branch 231 connected to 1, it is input to the optical receiver 251 to be received and branched. The wavelength 1548 nm (λ1) output from the optical multiplexer / demultiplexer 211 is used.
When the EDFA gate 241 is turned off under the control of the control means 270, the signal light of EDFA gate 2
The output from 41 is cut off. At this time, the optical transmitter 261
The signal light having a wavelength of 1548 nm (λ1) output from the optical branching unit 231 is connected to the optical branching unit 221 by the optical branching unit 231,
11 and inserted.

For each of the other wavelengths λ 2 to λ 4, the light transmission path through which the light flows has the same configuration from the optical multiplexer / demultiplexer 211 to the light reflecting mirrors 282 to 284. The wavelength-multiplexed light passes through an optical circulator 280 connected to the optical multiplexer / demultiplexer 211 and is output.
Therefore, it is possible to add and drop an optical signal having an arbitrary wavelength in the node.

Next, a third embodiment of the present invention will be described with reference to FIG.

The wavelength ADM apparatus (30) shown in FIG.
0: not shown) indicates an optical demultiplexer / demultiplexer 311, an optical branch 321
To 224, optical splitters 331 to 334, EDFA gate 34
1 to 344, optical receivers 351 to 354, optical transmitter 361
364, control means 370, optical branches 381 to 384, and optical isolators 391 to 394.

The third embodiment differs from the second embodiment in that each of the EDFA gates 341 to 344, the optical isolators 391 to 394, and the optical branch 38
1 to 384 are connected in series, and the last optical branch 38
4 is connected to the first EDFA gate 341 to form a loop.
1 to 224 are optical branches 334, 331, and 33, respectively.
2,333, respectively, in the loop configuration for the wavelength in the previous order.

The signal light input to the wavelength optical ADM apparatus (300) has a wavelength of 1548 nm (λ1) and a wavelength of 1550 nm (λ1).
2), four wavelengths of 1552 nm (λ3) and 1554 nm (λ4) are multiplexed, and these lights are input to an optical multiplexer / demultiplexer 311 typified by an arrayed waveguide diffraction grating.

The optical demultiplexer / demultiplexer 311 demultiplexes the received light and outputs the demultiplexed light to different optical branches 321-324.
The light received from the optical branches 321 to 324 is multiplexed and output. Therefore, each of the optical branches 321 to 324 has only one wavelength of light.

The optical branch 321 outputs the light having a wavelength of 1548 nm (λ 1) received from the optical multiplexer / demultiplexer 311 to the optical branch 334 and the optical receiver 351, respectively.
Is transmitted to the optical multiplexer / demultiplexer 311.

The optical branch 334 receives the light having the wavelength of 1548 nm (λ 1) received from the optical branch
The light having a wavelength of 1554 nm (λ4) received from the optical branch 384 and the optical transmitter 364 is output to the optical branch 321.

Therefore, the optical branch 331 outputs the light having the wavelength of 1550 nm (λ 2) received from the optical branch 322 to the EDFA gate 342 via the optical branch 381, and receives the wavelength 1548 nm (from the optical branch 381 and the optical transmitter 361). λ1)
Is output to the optical branch 322.

The EDFA gate 341 is connected to the control unit 370
When the light received from the optical branch 384 is allowed to pass through, the passed light is sent to the optical isolator 391,
The optical isolator 391 has a wavelength of 1548n out of the received light.
Only the light of m (λ1) is passed and output to the optical branch 381.

The components for other wavelengths are connected in the same manner.

Next, passing, dropping, and insertion of signal light in the operation of the wavelength ADM apparatus (300) will be described.

First, in the case of passing, the wavelength 1548 nm (λ 1) output from the optical multiplexer / demultiplexer 311 is supplied to the optical branch 321.
Signal light passes through the EDFA gate 341 via the optical branches 334 and 384, thereby forming an optical isolator 391.
Through the optical splitters 331 and 322 connected by the optical splitter 381 having a split ratio of 1: 1.

In the case of a branch, the wavelength 1548 nm (λ 1) output from the optical multiplexer / demultiplexer 311 is added to the optical branch 321.
Is transmitted to the optical receiver 351 connected to the optical branch 321.
Is input and received.

In the case of insertion, the wavelength 1548 nm (λ 1) output from the optical multiplexer / demultiplexer 311 is added to the optical branch 321.
The signal light of EDFA gate 341 is turned off under the control of control means 370,
The output from 1 is cut off. At this time, the wavelength 1548 output from the optical transmitter 361 under the control of the control means 370.
The signal light of nm (λ1) is split by the optical branch 331 into the optical branch 3
22 and is input to the optical multiplexer / demultiplexer 311.

For the light of the other wavelengths λ 2 to λ 4, the optical transmission path through which the light flows depends on the optical branches 322 to 324 connected to the optical multiplexer / demultiplexer 311 and the optical branches 381 to 383 forming a loop. Each followed by optical branch 3
82 through 384, 381 and optical branch 322 through
324 and 321 are connected to each other. As described above, it is possible to add / drop an optical signal of an arbitrary wavelength in a node.

Next, with reference to FIG. 6, regarding the monitoring of the wavelength ADM apparatus 400 in the fourth embodiment of the present invention, the monitoring items shown in FIG.
The description will be made in the order of S, OLOW, and OSD.

The wavelength optical ADM device 400 shown in FIG.
Has a configuration similar to that of the wavelength ADM apparatus 100 shown in FIG. 1, and only an outline is shown in the figure. That is, the optical demultiplexer 411, the optical branch 424, the gates 431 to 431
434 and an optical multiplexer 412 are illustrated, and an optical branch 424 and an optical layer monitor device 484 are illustrated only for a part of the wavelength of 1554 nm (λ4). This optical layer monitoring device 484 corresponds to the optical signal failure monitoring means 80 shown in FIG. Further, it is assumed that a part of the optical signal input to the wavelength optical ADM apparatus 400 is branched by the optical branch 420 to the optical layer monitor apparatus 480.

The signal light input to the wavelength optical ADM apparatus 400 has wavelengths of 1548 nm (λ1), 1550 nm (λ2),
Four wavelengths of 552 nm (λ3) and 1554 nm (λ4) are multiplexed. These lights are input to an optical multiplexer / demultiplexer 411 typified by an arrayed waveguide diffraction grating, and are also split into an optical branch 420. The monitor light is branched into light and input to an optical layer monitor 480 for monitoring the light intensity of the monitor light.

That is, the optical layer monitor 480 is
The light S / N ratio is determined from the ratio between the light intensity within a certain wavelength range including at least the signal light and the intensity of the spontaneous emission light within a wavelength range having a width equal to the wavelength range and different from the wavelength range. By calculating, the presence or absence of the signal light is determined, or the presence or absence of the signal light is determined from the light intensity within a certain wavelength range including the signal light to monitor the light intensity, and OLOS (Optical Loss Os).
f Signal) to detect a communication failure due to a fiber break or the like.

Next, the wavelength-division multiplexed light is input to an optical demultiplexer 411 represented by an arrayed waveguide diffraction grating and output to different gates 431 to 434, respectively. That is, at each of the gates 431 to 434, only light of one wavelength exists.

Therefore, for example, a part of the signal light having a wavelength of 1554 nm (λ 4) output from the optical demultiplexer 411 to the gate 434 is optically split by the optical splitter 424 as monitor light and input to the optical layer monitor 484. Then, the light intensity is monitored by the optical layer monitor device 484.

The optical layer monitor 484 determines the light intensity within a wavelength range of a predetermined width including at least the signal light, based on the narrow transmission bandwidth characteristics of the arrayed waveguide diffraction grating and the monitored light intensity. Light having a width equivalent to that of the wavelength range and the intensity of the spontaneous emission light in a wavelength range different from the wavelength range.
By calculating the N ratio or monitoring the wavelength shift of the signal light from the light intensity within the wavelength range, the OLOW (Opti
By detecting the cal loss of wavelength, a communication failure due to a wavelength shift of the light source or the optical filter or the like is detected.

Further, the optical layer monitor 484 has a light intensity within a certain wavelength range including at least the signal light and a spontaneous emission within a wavelength range having a width equal to the above wavelength range and different from the above wavelength range. The OSD (Optical Signal) is calculated by calculating the light S / N ratio from the ratio with the light intensity or monitoring that the light S / N ratio has dropped below a predetermined threshold.
nal Degrade) to detect a communication failure due to an abnormality in the communication device.

As described above, monitoring in the optical layer can be realized by the optical layer monitoring device.

Next, as a fifth embodiment of the present invention, an operation when the wavelength ADM apparatus 500 has a fault will be described with reference to FIG.

FIG. 7 shows an example in which two of the wavelength ADM devices shown in FIG. 6 are connected by one optical transmission line. Therefore, it is assumed that the configuration of the wavelength optical ADM device is exactly the same.

In the wavelength optical ADM apparatus 500 shown in FIG. 7, an optical demultiplexer 511, an optical branch 524, and gates 531 to 5
34, optical multiplexer 512 and optical layer monitor device 584
Only the optical signal to be input is shown in FIG.
It is assumed that a part is branched to the optical layer monitor device 580 by 20. Similarly, in the wavelength optical ADM device 501, the optical demultiplexer 515, the optical branch 528, the gates 535 to 538,
Only the optical multiplexer 516 and the optical layer monitor 588 are shown, and an optical signal to be input is partly branched by the optical branch 529 to the optical layer monitor 589.

The signal light input to the wavelength optical ADM apparatus 500 has wavelengths of 1548 nm (λ1), 1550 nm (λ2),
Four wavelengths of 552 nm (.lambda.3) and 1554 nm (.lambda.4) are multiplexed. These lights are input to an optical multiplexer / demultiplexer 511 represented by an arrayed waveguide diffraction grating, and are also split into an optical branch 520. The monitor light is branched into light and input to an optical layer monitor 580 that monitors the light intensity of the monitor light. The wavelength multiplexed light described above is input to an optical demultiplexer 511 represented by an arrayed waveguide diffraction grating and output to different gates 531 to 534, respectively. That is, the gate 53
In each of 1 to 534, only light of one wavelength exists.

If a signal light having a wavelength of 1554 nm (λ 4) is output from the optical demultiplexer 511 and a failure occurs in which signal transmission downstream cannot be performed due to disconnection of the optical fiber connected to the optical branch 524. Is assumed.

In this situation, the optical layer monitor device 584 located downstream of the location where the failure occurred cannot detect the optical input, and
Detect OLOS. The optical layer monitor 584
Immediately after the detection of the LOS, by turning off the gate 534 and shutting off the output of the gate, AIS-O is issued downstream to notify the occurrence of a fault.

In the wavelength optical ADM device 501 which becomes the next node connected via the optical transmission line, the input signal light usually has wavelengths of 1548 nm (λ1), 1550 nm (λ2),
Four wavelengths of 1552 nm (λ3) and 1554 nm (λ4) are multiplexed.

However, since the gate 534 is turned off and the gate output is cut off due to the disconnection of the optical fiber in the wavelength light ADM device 500, the wavelength light ADM device 501 is turned off.
OLOS is also detected in the optical layer monitor device 588 of FIG. Accordingly, in the wavelength ADM apparatus 501, the AIS-O is issued downstream by turning off the gate 538.

On the other hand, there is no effect on transmission lines of other wavelengths where no failure has occurred, and the same optical transmission as before the occurrence of the failure can be performed.

As described above, the optical layer monitor of the wavelength ADM apparatus detects the OLOS and turns off the gate switch immediately downstream of the OLOS, thereby affecting the signal light in the optical layer and other wavelengths. Without giving it, it is possible to notify the downstream of a fault occurrence.

Next, with reference to FIG. 8, the sixth embodiment of the present invention will be described with reference to FIG.
The operation different from that described above will be described.

FIG. 8 shows the two-wavelength light AD shown in FIG.
Wavelength device ADM device 500 out of M devices 500 and 501
Branch 544 between the gate 534 and the optical multiplexer 512
And an optical transmitter 564 are additionally shown.
Therefore, it is assumed that the configuration and the functions of the components in FIG. 8 are exactly the same as those in FIG.

Now, assume that a signal light having a wavelength of 1554 nm (λ 4) is output from the optical demultiplexer 511 and a failure occurs in which signal transmission downstream cannot be performed due to disconnection of the optical fiber connected to the optical branch 524. Is assumed. In this situation, the optical layer monitor device 584 located downstream from the fault location
Cannot detect the light input and detects OLOS. Immediately after the detection of the OLOS, the optical layer monitor device 584 issues an AIS-O downstream to notify the occurrence of a failure by turning off the gate 534 and cutting off the output of the gate.

However, here, the wavelength 1
When the signal light of 554 nm (λ4) is output to the optical multiplexer 516 via the optical branch 534, the wavelength light A of the next node is output.
In the optical layer monitor device 588 of the DM device 501,
OLOS is not detected.

As described above, AIS-O is interrupted on the way by inserting a signal of the same wavelength. However, even during the operation of dropping and adding, the signal light in the optical layer and affecting signal light of other wavelengths is affected. Without giving, it is possible to detect the occurrence of a fault and to notify the details of the fault to the downstream.

Next, with reference to FIG. 9, a description will be given of an operation different from those in FIGS. 7 and 8 when the wavelength optical ADM apparatus 500 has a failure in the seventh embodiment of the present invention.

FIG. 9 shows the two-wavelength light AD shown in FIG.
In the optical transmission line connecting the M devices 500 and 501, the inter-node communication device 591 branched by the optical branch 540 on the wavelength optical ADM device 500 side, and the wavelength optical ADM device 501
Node communication device 5 branched by optical branch 529 on the side
99, each of which is provided.

Now, a case where a signal light having a wavelength of 1554 nm (λ 4) is output from the optical demultiplexer 511 and a failure occurs in which signal transmission to the downstream is impossible due to disconnection of the optical fiber connected to the optical branch 524. Is assumed. In this situation, the optical layer monitor device 584 located downstream from the fault location
Cannot detect the light input and detects OLOS. Immediately after the detection of the OLOS, the optical layer monitor device 584 issues an AIS-O downstream to notify the occurrence of a failure by turning off the gate 534 and cutting off the output of the gate.

In this configuration, the inter-node communication device 5
By using signal light of a different wavelength from the above-mentioned signal light between 91 and 599, network management information can be communicated at the same time as notification of failure occurrence.

Next, a self-healing network using wavelength optical ADM devices 600 and 601 in the eighth embodiment of the present invention will be described with reference to FIG.

FIG. 10 shows a case where two of the wavelength ADM devices shown in FIG.
The M device 601 has an optical layer monitor device 681, and the other wavelength optical ADM device 602 has an optical layer monitor device 681.
2 (not shown).
A signal input to both of the optical layer monitoring devices 681 and 682 is transmitted through the selector switch 600 to the optical receiver 65.
1 are connected.

As shown in FIG. 10, signals are transmitted in opposite directions to the optical transmission lines connected to the wavelength ADM devices 601 and 602, and one of the wavelength ADM devices 601 is used as a working line. And the other wavelength optical ADM device 60
It is assumed that a spare line is connected to 2. Therefore, it is assumed that the selector switch 600 connects the signal of the wavelength optical ADM device 601 to which the working line is connected to the optical receiver 651 with respect to the working line.

In a normal state, the wavelength light A connected to the working line
The signal light branched from the DM device 601 is input to the optical layer monitor device 681, and the wavelength light AD connected to the spare line
The signal light branched from the M device 602 is input to the optical layer monitor device 682.

Each of the optical layer monitoring devices 681 and 682 monitors OLOS, OLOW, OSD or AIS-O due to occurrence of a fault.

Here, when the optical signal interruption failure monitoring signal is detected by the optical layer monitor device 681, the selector switch 600 recognizes that the optical signal interruption failure monitoring signal is not detected by the optical layer monitor device 682. Then, the connection of the optical receiver 71 is switched to receive the signal. By the above method, even when a failure occurs, a self-healing network can be realized in the optical layer.

In the above description, it has been described that light of four wavelengths is multiplexed in all the examples. However, the number of multiplexing is not limited to the number described in the above embodiment. Any number of wavelengths, for example, 8, 16, 32, 64, etc., may be freely set. In addition, the wavelength of the input light 1
It is not limited to the 550 nm band, but can be set freely, such as the 1300 nm band. Also, the signal speed is not particularly limited, and may be 2.5 Gbps, 5 Gbps, 10 Gbps.
Bit rate free setting such as bps is possible.

In addition, here, the description is made by taking an example of an arrayed waveguide diffraction grating such as an optical demultiplexer, a multiplexor, and a multiplexer / demultiplexer. However, a wavelength router having a grating structure having the same function, a wavelength MUX coupler, and the like. For example, the same effects as those described in the above embodiments can be expected as long as they have the same function as the combination of the optical branching and the interference filter.

In addition, since the optical demultiplexing, the optical multiplexing, and the optical demultiplexing device represented by the arrayed waveguide diffraction grating and the like have different insertion loss depending on each wavelength, an optical attenuator may be appropriately inserted into each waveguide. It is also possible to perform light level equalization.

It is also possible to control the gain of each EDFA gate and semiconductor optical amplifier, or to control the reflectivity of the light reflecting mirror described in the second embodiment to equalize the light level for each wavelength. .

The configuration of the EDFA gate is particularly
The structure is not limited to F, but may be replaced by a structure in which aluminum, tellurium, or the like is added as an impurity to the fiber and excited by a pumping light source to perform light amplification.

The same effect can be achieved by using a gate switch such as a mechanical switch having a high on / off ratio, a lithium niobate switch, or a quartz switch instead of the EDFA gate and the semiconductor optical amplifier.

Further, in the above embodiment, the failure occurrence location is described and described in only one location in the wavelength optical ADM apparatus, and
Although each wavelength optical ADM device is illustrated as being provided for each wavelength, the optical layer monitor device according to the present invention can be used in all optical transmission lines, optical transmitters, and the like in a wavelength optical ADM device if there is only one location. It is possible to cope with a case where a fault occurs in several places and a fault in an optical transmission line between wavelength optical ADM devices. Therefore, one device that can identify these faults may be used.

Further, the installation position of the optical layer monitor device is not limited to the position described in the embodiment, and it is possible to freely install the optical layer monitor device and monitor it by using an appropriate optical branch.

Also, when constructing a ring network, an optical layer monitor can be freely installed, and an optical layer monitor can be installed not only in a wavelength optical ADM apparatus but also in an optical regenerative repeater to prevent signal interruption. AI at the time of occurrence
By issuing an SO, self-healing in the optical layer is possible.

As described above, the embodiment has been illustrated and described. However, the block configuration or the block arrangement by dispersing and merging the functions is free as long as the above functions are satisfied, and the above description does not limit the present invention.

[0126]

A first effect of the present invention is that a wavelength optical ADM apparatus capable of dropping / adding signal light of an arbitrary wavelength in a node can be realized.

The reason is that an optical demultiplexer and an optical multiplexer are used to add / drop a signal light in a transmission line installed for each wavelength, and that an optical amplifier and an optical attenuator are used for each wavelength. This is because light level equivalent can be realized.

The second effect is that the amount of hardware to be mounted on the wavelength ADM apparatus can be reduced, and a reduction in the size and cost of the system can be expected.

The reason is that, in response to alarms (LOS, LOF, LOP, BER and AIS-L) in the SONET / SDH layer, optical signal interruption failure detection signals (OLOS, OLOW, OSD and AIS) in the optical layer are newly added. This is because redefining -O) eliminates the need for AIS processing hardware in the wavelength ADM apparatus, and further simplifies the control of the wavelength ADM apparatus because the AIS processing control is not required. It is.

The third effect is that the existing SONET / SDH
It is possible to maintain compatibility with the standard APS.

The reason is that the optical layer uses OLOS, OLO
The network failure detected by at least one of the optical signal interruption failure detection signals of W and OSD is AIS-
O and converted to the conventional LOS for the SONET layer
This is because the line termination is able to recognize the failure detected in the optical layer and recover from the failure.

The fourth effect is that the monitoring system and the failure recovery system in the optical layer can be used without competing not only with the SONET / SDH standard but also with other framing format transmission apparatuses, that is, without using the framing format. It can be introduced to networks. The reason is that AIS-O in the optical layer
Is notified downstream by interrupting the transmission of the optical signal.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing one configuration of an EDFA gate switch.

FIG. 3 is an explanatory diagram showing the correspondence of an optical signal cutoff detection signal between a SONET / SDH layer and an optical layer.

FIG. 4 is a block diagram showing a second embodiment of the present invention.

FIG. 5 is a block diagram showing a third embodiment of the present invention.

FIG. 6 is a block diagram showing a fourth embodiment of the present invention.

FIG. 7 is a block diagram showing a fifth embodiment of the present invention.

FIG. 8 is a block diagram showing a sixth embodiment of the present invention.

FIG. 9 is a block diagram showing a seventh embodiment of the present invention.

FIG. 10 is a block diagram showing an eighth embodiment of the present invention.

[Explanation of symbols]

11, 411, 511, 515 Optical demultiplexer 12, 412, 512, 516 Optical demultiplexer 21 to 2n, 41 to 4n, 221-224, 231-2
34, 321-324, 331-334, 381-38
4, 420, 424, 520, 524, 528, 529
Optical branch 30, 241-244, 341-344 EDFA gate switch 31-3n Optical gate switch 51-5n, 251-254, 351-354, 651
Optical receivers 61-6n, 261-264, 361-364, 564
Optical transmitters 70, 270, 370 Control means 80 Optical signal failure monitoring means 100, 200, 300, 400, 500, 501, 6
01, 602 wavelength optical ADM device 131 pumping light source 132 WDM coupler 133 EDF (erbium-doped fiber) 211, 311 optical demultiplexer / demultiplexer 281-284 light reflecting mirror 280 circulator 391-394 optical isolator 480, 484, 580, 584, 588 , 589, 6
81 Optical layer monitor 591, 599 Communication device between nodes 600 Selector switch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H04B 10/02 H04B 9/00 U

Claims (25)

[Claims] 1. An optical demultiplexer for demultiplexing wavelength-division multiplexed light input from one optical transmission line for each of a plurality of wavelengths, and one optical output for each of the plurality of wavelengths of the optical demultiplexer. A plurality of optical receivers to be connected, a plurality of optical gate switches for connecting one optical output of the demultiplexer input to each of the optical receivers, and controlling passage and cutoff of light, and the optical receiver A plurality of optical transmitters each having one optical output corresponding to the wavelength multiplexed light, and connected to the optical output of the optical gate switch and the optical output of the optical transmitter; An optical add-drop multiplexer (ADM), comprising: an optical multiplexer that outputs multiplexed light. 2. The wavelength ADM apparatus according to claim 1, wherein said optical gate switch includes at least a part thereof an erbium-doped fiber array.
A wavelength optical ADM device characterized by being a gate. 3. The wavelength ADM apparatus according to claim 1, wherein at least a part of said optical gate switch is a semiconductor optical amplifier. 4. A circulator for inputting wavelength-division multiplexed light from one optical transmission line and outputting wavelength-division multiplexed light to the other optical transmission line. An optical multiplexer / demultiplexer that outputs each of the plurality of split lights to the input and output of the optical circulator, while inputting a plurality of split lights to the wavelength multiplexing; A first optical branch that is connected to a device to input and output each of the lights separated for each wavelength, and the other to optically split each of the lights separated for each input and output wavelength;
An optical receiver for connecting one optical output of the first optical branch, and an optical transmitter corresponding to the optical receiver and having one optical output constituting the wavelength-division multiplexed light; An optical gate switch corresponding to each of the plurality of lights and controlling passage and blocking of the light, and corresponding to each of the plurality of branched lights, and connected to the optical input / output of each of the first optical branches, On the other hand, a second optical branch for connecting to one of the optical gate switches to input and output light and input light from the optical transmitter, and the optical gate switch corresponding to each of the plurality of demultiplexed lights. And a light reflection mirror connected to the other end of the optical circulator. The wavelength multiplexed light output from the optical input / output of the optical circulator and received by the optical multiplexer / demultiplexer receives the optical input / output of the optical circulator from the optical multiplexer / demultiplexer. When the light is output to Wavelength light ADM and wherein the output from the light output over curator to the optical transmission line. 5. The wavelength ADM apparatus according to claim 4, wherein at least a part of said optical gate switch is an EDF.
A wavelength optical ADM device, which is an A gate. 6. The wavelength ADM apparatus according to claim 4, wherein at least a part of said optical gate switch is a semiconductor optical amplifier. 7. An optical demultiplexer for demultiplexing wavelength-division multiplexed light input from an optical transmission line for each wavelength, and multiplexing the demultiplexed light for output to an optical transmission line. A first optical branch that is connected to the optical multiplexer / demultiplexer to input and output each of the lights separated for each wavelength, and to optically split each of the input and output lights separated for each wavelength, An optical receiver for connecting one optical output of the first optical branch, and an optical transmitter corresponding to the optical receiver and having one optical output constituting the wavelength-division multiplexed light; An optical gate switch corresponding to each of the plurality of lights and controlling passage and blocking of light; an optical isolator corresponding to each of the plurality of split lights and passing only the corresponding optical output of the optical gate switch; Corresponding to each of the waved light,
On the other hand, it is connected to each optical input / output of the first optical branch,
On the other hand, each of the light separated for each input / output wavelength is optically branched, and the second optical branch for inputting light from the optical transmitter corresponds to each of a plurality of demultiplexed lights. A third optical branch connected to the optical input / output of each of the second optical branches and receiving the optical output of the optical isolator and outputting light having a different wavelength from the optical output to the optical gate switch. , Each of the lights separated for each wavelength,
After passing through the optical multiplexer / demultiplexer, the first optical branch, the second optical branch, the third optical branch, the optical gate switch, and the optical isolator, the separated optical signal is transmitted to an adjacent wavelength. A wavelength optical ADM apparatus, comprising: returning to the optical multiplexer / demultiplexer via a third optical branch and the second optical branch; the optical multiplexer / demultiplexer multiplexes and outputs light; 8. The wavelength ADM apparatus according to claim 7, wherein said optical gate switch includes at least a part of an EDF.
A wavelength optical ADM device, which is an A gate. 9. The wavelength ADM apparatus according to claim 7, wherein at least a part of said optical gate switch is a semiconductor optical amplifier. 10. The wavelength ADM apparatus according to claim 1, wherein at least one of the input and output of the optical receiver includes an optical gate switch, an EDFA gate, and an EDFA gate. A wavelength optical ADM device, wherein one of the semiconductor optical amplifiers is inserted. 11. The wavelength ADM apparatus according to claim 1, wherein each of said optical gate switch, said EDFA gate, and said semiconductor amplifier is a gate, and said gate is turned on / off. State, the presence or absence of an optical signal input to the optical receiver, and the presence or absence of an optical signal output from the optical transmitter. A wavelength light ADM device comprising a control unit for selecting a wavelength. 12. The wavelength ADM apparatus according to claim 11, wherein the light intensity within a wavelength range having a predetermined width including at least the signal light, a wavelength equal to the wavelength range, and a wavelength different from the wavelength range. From the ratio with the intensity of the spontaneous emission light in the region, the light S / N
An optical signal cutoff signal (hereinafter referred to as an OLOS signal) is obtained by calculating the ratio to determine the presence or absence of the signal light or by determining the presence or absence of the signal light from the light intensity within a certain wavelength range including the signal light. : Optical Loss of Signal)
And an optical signal wavelength shift signal (hereinafter, OLOW: Optical Loss of Wavelength) by monitoring the wavelength shift of the signal light from the light intensity in the wavelength range.
A function of monitoring the interruption failure of the optical signal by detecting any one of the above, the light intensity within a wavelength range of a predetermined width including at least the signal light and a width equivalent to the wavelength range and the wavelength range is From the ratio with the intensity of the spontaneous emission light in different wavelength ranges, the light S
/ N ratio is calculated, and when the optical S / N ratio falls below a predetermined threshold, an optical S / N ratio reduction signal (hereinafter referred to as OS
D: Optical Signal Degrade), and an optical signal failure monitoring means for detecting the OLOS, the OLOW, and the OSD as a failure detection signal and detecting at least one of the failure detection signals. When the optical signal failure monitoring means detects at least one of the failure detection signals, the control means receives the detection signals, controls the gate, and outputs a signal light from an output corresponding to the detected input. By interrupting the signal, the detected failure detection signal is converted to a network failure detection signal (hereinafter, AIS-O: Optical Alarm Indication S) in the optical layer.
wavelength ADM apparatus, wherein the wavelength ADM apparatus converts the light into ignal). 13. An optical ADM device including the wavelength ADM device according to claim 11, an optical repeater amplifier, and a line terminator for terminating an optical signal, wherein at least one wavelength is included in one optical fiber. 13. An optical signal failure monitoring method in an optical network handling an optical signal wavelength-multiplexed by using the optical signal failure monitoring means according to claim 12 as an optical layer monitor device. 14. The optical signal failure monitoring system according to claim 13, wherein when the wavelength optical ADM apparatus detects at least one of the failure detection signals, the control means detects the failure detection signal. By blocking the signal light from the output corresponding to the input of the network, the failure detection signal is converted to a network failure detection signal (AIS-
O: Optical signal failure monitoring method characterized by having a function of converting the signal into Optical Alarm Indication Signal). 15. An optical ADM device and an optical repeater amplifier each including at least the optical layer monitor device according to claim 13, wherein the optical ADM device, the optical repeater amplifier, and a transmission device connected to an optical layer are connected. An optical signal fault monitoring method in an optical network for handling an optical signal wavelength-multiplexed with at least one wavelength in one optical fiber, wherein the optical layer monitor apparatus includes an OLOS in the optical layer in the optical network. And monitoring the optical signal interruption failure in the network by at least one of AIS-O and AIS-O so as to be independent of the framing format of the transmission device connected to the optical layer in the optical network. Monitoring method. 16. The optical signal failure monitoring system according to claim 15, wherein the OLOS for a network failure in an optical layer of the optical network using one of the optical ADM apparatus and the optical repeater amplifier is transmitted to the AI.
Notifying the transmission apparatus connected to the optical layer of the framing format by notifying a network failure from the optical layer to a transmission apparatus connected to a layer other than the optical layer by converting the signal into an S-O. Characteristic optical signal failure monitoring system. 17. The optical signal failure monitoring system according to claim 15, wherein a signal notifying occurrence of a failure in a transmission device connected to said optical layer using one of said optical ADM device and said optical repeater amplifier is provided. Instead, when monitoring a fault in an optical network using the OLOS and the AIS-O in the optical layer, the signal regeneration repeater is provided in the optical network upstream of a network fault detection position of the optical ADM apparatus. When arranged, between the optical ADM device and the signal regeneration repeater of the transmission device standard connected to the optical layer, a line termination device of the transmission device standard connected to at least one or more of the optical layers Is arranged, so that the signal regenerator repeats the line of the transmission device standard connected to the downstream optical layer when a network failure is detected. The line regenerator recognizes a monitoring signal issued by the signal regenerator to notify the network terminator of the occurrence of the network failure from the signal regenerator to recover the network failure. Optical signal failure monitoring method. 18. The optical signal failure monitoring system according to claim 15, wherein a signal notifying the occurrence of a failure in a transmission device connected to said optical layer using one of said optical ADM device and said optical repeater amplifier. Alternatively, when monitoring a fault in an optical network using at least one of the OLOS and the AIS-O in the optical layer, the signal is provided upstream of a network fault detection position of the optical ADM device in the optical network. When a regenerative repeater is arranged, the signal regenerative repeater is provided with the AIS-O issuing function in the optical layer, and the optical repeater amplifier and the optical ADM downstream of the signal regenerative repeater are provided.
By notifying the network failure to at least one of the devices, the recovery of the network failure by switching the optical path performed by the optical ADM device in the optical layer, and the O of the network failure in the optical layer.
The recovery of the network failure by the transmission device connected to the optical layer, which is performed by notifying the transmission device connected to the optical layer of the network failure from the optical layer by converting the LOS into the AIS-O. An optical signal failure monitoring method comprising: 19. The optical signal failure monitoring system according to claim 15, wherein a signal notifying the occurrence of a failure in a transmission device connected to said optical layer using one of said optical ADM device and said optical repeater amplifier. Alternatively, when monitoring a fault in an optical network using the OLOS and the AIS-O in the optical layer, network management information is allocated to a wavelength band different from a main signal light wavelength band in the optical network, and the optical ADM is allocated. An optical signal failure monitoring method for performing network information communication independent of a framing format between nodes by an apparatus and between nodes of the optical ADM apparatus and the line terminator. 20. An optical ADM apparatus, an optical repeater amplifier, and an SOA, each having at least the optical layer monitor apparatus according to claim 13 mounted thereon.
NET (Synchronous Optical Network) / SDH (Sync
(hronous Digital Hierarchy) In an optical network including a standard line terminator and handling an optical signal wavelength-multiplexed by at least one wavelength in one optical fiber,
When a network failure is detected in the SONET / SDH section layer in the optical network, it is allocated to a line overhead to notify the line terminator downstream of the network failure detection position of the occurrence of the network failure. Network failure detection signal (hereinafter AIS-L: Line Alarm Indicat
The SONET / SDH layer that reads the AIS-L to recognize the network failure and outputs the SOIS / SDH again to the line termination to notify the network failure to the line termination. 3. An optical signal failure monitoring system, wherein an optical signal interruption failure in a network is monitored by at least one of the OLOS and the AIS-O in the optical layer instead of the AIS-L. 21. When a network failure occurs in an optical layer in an optical network using one of the optical ADM apparatus and the optical repeater amplifier according to claim 20,
An optical signal characterized by causing the line terminator to intentionally detect LOS (Loss of Signal) by converting OLOS into AIS-O, and notifying the SONET / SDH layer of a network failure from the optical layer. Fault monitoring method. 22. A SONET / S using one of the optical ADM apparatus and the optical repeater amplifier according to claim 20.
In an optical network for monitoring a network failure using at least one of the OLOS and the AIS-O in the optical layer instead of the AIS-L in the DH layer, the SONET is upstream of a network failure detection position of the optical ADM apparatus. / SDH standard signal regenerator is disposed between the optical ADM apparatus and the signal regenerator.
By arranging an H-standard line terminator, the signal regenerator can notify the downstream SONET / SDH standard line terminator of the occurrence of the network failure when the signal regeneration repeater detects a network failure. The network failure is recovered by causing the line terminator to recognize the AIS-L issued by the signal regeneration repeater and operating the SONET / SDH standard APS (Automatic Protection System). Signal failure monitoring method. 23. A SONET using one of the optical ADM apparatus and the optical repeater amplifier according to claim 20.
In an optical network for monitoring a network failure using at least one of the OLOS and AIS-O in the optical layer instead of the AIS-L in the / SDH layer, a signal is reproduced upstream from a network failure detection position of the optical ADM apparatus. In the case where a repeater is arranged, the signal regeneration repeater is provided with the AIS-O issuing function in the optical layer, so that the signal regeneration repeater is provided with one of the optical repeater amplifier and the optical ADM device downstream of the signal regeneration repeater. By notifying the network failure, the optical ADM apparatus performs recovery of the network failure by switching an optical path in the optical layer, and reports the network failure in the optical layer from the OLOS to the AI.
Converted to SO and intentionally added to the line terminator by LOS
(SONET / SDH) performed by notifying a network failure from the optical layer to the SONET / SDH layer by detecting (Loss of Signal).
An optical signal failure monitoring system comprising at least one of recovery from the network failure by an automatic protection system (APS). 24. A SONET using one of the optical ADM apparatus and the optical repeater amplifier according to claim 20.
In an optical network for monitoring a network failure using at least one of OLOS and AIS-O in the optical layer instead of AIS-L in the / SDH layer, network management information is allocated to a wavelength band different from the main signal light wavelength band. An optical signal fault monitoring system, wherein network information communication is performed between the optical ADM devices forming nodes by means of the network and between the optical ADM device and nodes between the optical ADM device and the line terminator. 25. A ring network in which at least one wavelength optical ADM device equipped with the optical layer monitor device according to claim 13 is connected in a ring shape by at least one transmission line. A ring network comprising detecting a failure using at least one of them, switching to a spare transmission line, and performing recovery from the failure by at least one of network reconfigurations.