KR100198441B1 - Optical divider combiner for full duplex line switching ring network - Google Patents

Abstract

The present invention relates to an optical branch coupling device for a two-wire bidirectional line switching ring network, wherein the NxN array waveguide means used as optical multiplexing and optical demultiplexing means and a plurality of signals inputted according to the presence or absence of an abnormal optical line 2x2 optical switching means for combining or passing therethrough, first 1x2 optical switching means for providing a channel for monitoring the counterclockwise ring with or without optical paths, and for monitoring the clock ring with or without optical paths Second 1x2 optical switching means for providing a channel path, optical fiber amplification means for compensating for losses occurring in the optical path or the waveguide means, and optical detection means for detecting a monitoring channel according to whether there is an abnormality in the optical path. In the two-wire bidirectional line switching ring network, continuous optical transmission service can be provided even in the case of an optical fiber failure.

Description

Optical branch coupling device for two-wire bidirectional line transfer ring network

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical branch coupling device. In a synchronous transmission network, a ring network having a self-healing function is used to continuously provide a service even if a problem occurs on a line. It is composed of the opposite operation ring and the reserve ring, the protection ring (Protection Ring) is a device for continuously providing a service by using this when a failure occurs in the working ring (Working Ring).

In addition, the ring network is classified into one-way and two-way according to the number of directions of the optical signal, divided into a path switch and a line switch according to the transfer method in the event of a failure. In the event of a failure, the optical switch on the operation ring is used to switch the line to the reserve ring using a loop-back ring switch.

The self-healing ring mainly used in the synchronous transmission network is a bidirectional line switching ring, which is divided into two wires and four wires according to the number of optical fiber lines used. In each of the two wires, each line is divided into an operating band and a spare band. There are two tracks, one for operation and one for reserve.

The present invention belongs to a two-wire bidirectional line switching method.

In the present invention, after separating the wavelength band of the operating ring and the preliminary ring by using the wavelength division characteristics, the optical path for the operating channel and the optical path for the reserve channel in the array waveguide grating which is an optical device for wavelength division multiplexing and demultiplexing. At the same time, in normal operation, the remaining traffic channel is transmitted by using the path for the reserve channel, and when an error occurs in the optical path, the optical path is looped back using the ring switch and the opposite direction ring is performed by the optical path for the reserve channel. In order to provide a self-healing function by monitoring the state of the network using a method such that the operating channel of the transmission and the optical detector and the optical switch.

1 is a configuration diagram of an NxN array waveguide grating,

2 is a configuration diagram of a 2x2 optical switch,

3 is a block diagram of an optical branch coupling device for a two-wire bidirectional line steel ring network in a steady state according to an embodiment of the present invention,

4 is a block diagram of an optical branch coupling device for a two-wire bidirectional line steel ring network in an optical line abnormal state according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

a1 (100): Arrayed waveguide grating for clockwise ring

a2 (200): arrayed waveguide grating for counterclockwise ring

b1 (11): 2x2 optical switch for regulating the branching / combination or passage of the operating channel in the clockwise ring

b2 (13): 2x2 optical switch for regulating the branching / combination or passage of the operating channel in the counterclockwise ring

c1 (12): 2x2 optical switch to control branching / combination or passage of residual traffic channels in clockwise ring

c2 (14): 2x2 optical switch to control branching / combination or passage of residual traffic channels in anticlockwise ring

d1 (21), d2 (22): 2x2 optical switch for the configuration of the ring switch used when looping back the operating channel that proceeds in the counterclockwise direction

e1 (23), e2 (24): 2x2 optical switch to configure the ring switch used when looping back the operating channel which proceeds clockwise in the counterclockwise direction

f1 (41): 1x2 optical switch used to advance the monitoring channel clockwise at all times with or without optical path

f2 (42): 1x2 optical switch used to advance the monitoring channel counterclockwise at all times with or without optical path

g1 (61), h1 (63): optical path for clockwise ring

g2 (62), h2 (64): optical path for the counterclockwise ring

i1 (31): fiber optic amplifier for compensating for losses in optical line g1 (61)

i2 34: fiber optic amplifier for compensating for losses in optical path h2 64

j1 (33): an optical fiber amplifier for compensating for losses in the arrayed waveguide grating a1 (100)

j2 (32): optical fiber amplifier for compensating for losses in array waveguide grating a2 (200)

k1 (51): An optical detector which detects a monitoring channel when there is no error in the optical line g1 (61) and which is not detected when an error occurs.

k2 (53): An optical detector in which a monitoring channel is detected when there is no error in the optical line h2 (64) and not detected when an error occurs.

l1 (52): An optical detector in which a monitoring channel is detected when an error occurs in the optical line g1 (61) and is restored.

l2 (54): Optical detector in which the monitoring channel is detected when an error occurs in the optical line h2 (64) and is restored.

The optical branch coupling device for a two-wire bidirectional line switching ring network provided by the present invention is a NxN array waveguide means used as optical multiplexing and optical demultiplexing means, and a branch / coupling of a plurality of signals inputted according to the presence or absence of an optical line. Or 2x2 optical switching means for passing therethrough, first 1x2 optical switching means for providing an anti-clockwise ring monitoring channel path regardless of whether there is an abnormality in the optical path, and a monitoring channel for a clockwise ring regardless of the abnormality of the optical path And a second 1x2 optical switching means for providing a path, an optical fiber amplifying means for compensating for losses occurring in the optical line or the waveguide means, and optical detection means for detecting a monitoring channel in accordance with an abnormality of the optical line.

The apparatus of the present invention simultaneously installs the optical path for the operating channel and the optical path for the spare channel in one array waveguide grating, and adjusts the switching state of the optical switch with the photodetector. Transmit the operating band through the optical path for transmission, transmit the remaining traffic band through the optical path for the reserve channel, and if an error occurs in the optical path, adjust the optical switch according to the position where the monitoring channel is detected by the optical detector. The operating band of the ring can be transmitted by the path for the spare channel of the counterclockwise ring, and the operating band of the counterclockwise ring can be transmitted by the path for the spare channel of the clockwise ring.

Hereinafter, with reference to the accompanying drawings will be described in detail the present invention.

FIG. 1 is a schematic diagram of an NxN array waveguide grating, FIG. 2 is a schematic diagram of a 2x2 optical switch, and FIG. 4 is a block diagram of an optical branch coupling device for a two-wire bidirectional line steel ring network in an optical line abnormal state according to an embodiment of the present invention.

Referring to FIG. 1, the configuration of an NxN arrayed waveguide grating (AWG) having N input / output ports is N is a wavelength division multiplexing optical device fabricated with a waveguide diffraction grating using well-developed silica technology. When the NxN arrayed waveguide grating is input to NxN array waveguide grating, the wavelength division multiplexed light source (λ ₁ to λ _N ) matching the transmission characteristics of the arrayed waveguide grating is input into the arrayed waveguide grating. The light source is divided into N so that each wavelength is output to an output port having a number that matches the number of wavelengths.

Conversely, if N light sources with wavelengths that match the transmission characteristics of the arrayed waveguide gratings are input to the input ports corresponding to the numbers of the respective wavelengths, the NxN arrayed waveguide gratings are combined into one within the arrayed waveguide gratings, N / 2 of the output ports. Only printed once

Because of these characteristics, array waveguide gratings are used not only as optical multiplexers and optical demultiplexers, but also in the construction of optical branch coupling devices by connecting two array waveguide gratings. That is, the wavelength division multiplexed light source with the first grating is demultiplexed for each port according to the wavelength, and the light source separated for each wavelength with the second grating is multiplexed again.

At this time, it is possible to perform the function of the optical branch coupling device by branching or combining any channel in the middle of connecting the two gratings.

Referring to FIG. 2, each state of a 2x2 optical switch driven by a voltage can be seen. The state of 2x2 includes a basic state 300, a state 400 in which no voltage is applied, and a voltage in which the voltage is applied. There is a cross state 500.

Referring to FIG. 3, an optical add / drop multiplexer (OADM) for a 2-fiber bidirectional line-switching ring network (BLSR / 2) of the present invention includes two NxNs. Arrayed waveguide gratings 100, 200, 2N 2x2 optical switches 21-24, 11-14, two 1x2 optical switches 41, 42, four fiber amplifiers 31-34, four photodetectors ( 51 to 54).

Port number N / 2 of the arrayed waveguide gratings 100 and 200 is used for input / output of a wavelength division multiplexed light source, and port number N is used to monitor an abnormality of an optical fiber line connected between optical branch coupling devices forming a ring network. It is used for input and output of the light source λ _N , and the remaining input / output ports connect the same numbers in a loop-back type with a 2 × 2 optical switch b1 (11) or b2 (13) in the center.

Port numbers 1 to N / 2-1 connected to the 2x2 optical switch b1 (11) in solid line in a1 (100), which is an array of clockwise ring waveguides, are optical paths for the operation channel, and the 2x2 optical switch c1 (12) and the dotted line. Port numbers N / 2 + 1 to N-1 connected are optical paths for the spare channels. In addition, the port numbers 1 to N / 2-1 connected in a solid line with the 2x2 optical switch b2 (13) in a2 (200), which is an arrayed waveguide grating of the counterclockwise ring, are optical paths for the operation channel, and the 2x2 optical switch c2 (14). ) And the port numbers N / 2 + 1 to N-1 connected by dotted lines are optical paths for the spare channels.

In the clockwise ring, wavelengths λ ₁ to λ _{N / 2-1} are operating bands, and the wavelengths λ _{N / 2 + 1} to λ _N-1 are reserved bands, and in the counterclockwise ring, wavelength λ ' _{N / 2 + 1} Λ ' _N-1 is the operating band and wavelength λ' ₁ to λ '_{' N / 2-1} are the reserved bands. In the clockwise ring, wavelengths λ _{N / 2 + 1} to λ _N-1 are used to transmit and receive the low-priority extra tracfic channel using the preliminary path of the clock ring. The wavelengths λ ₁ to λ _{N / 2-1} are used to transmit and receive the remaining traffic channels using the spare band of the counterclockwise ring.

The operation characteristics of the optical branch coupling device when the two-wire bidirectional line switching ring network of the present invention having the above configuration is operating normally are as follows.

First, N-1 wavelengths (λ ₁ ,..., Λ _{N / 2-1} , λ _{N / 2 + 1} ,..., Λ _N ) transmitted through the optical fiber line g1 (61) in the clockwise ring. The multiplexed optical signal passes through the optical fiber amplifier i1 31 to compensate for the losses experienced in the optical path, and the compensated optical signal passes through the bar 2x2 optical switch d1 21 and then arranged. It enters the port number N / 2 of the waveguide grating a1 (100).

The respective wavelengths are demultiplexed in the array waveguide grating so that the operating channels λ ₁ to λ _{N / 2-1} are looped back through the solid line, and the remaining traffic channels λ _{N / 2 + 1} to λ _N-1 are reserved channels. Loop back through the dotted line, which is the optical path. At this time, the 2x2 optical switch b1 (11) applies a voltage to a channel to be branched / coupled among the operating channels so that the state of the switch is cross, and if it is to be passed continuously, the state of the switch is bar (bar). 2x2 optical switch c1 (12) also applies a voltage to the channel to branch / combine among the remaining traffic channels to make the switch state cross, and if it wants to continue to pass the switch state. Keep the bar.

In this way, the unpassed channel and the newly combined channel in the optical branch coupling device are multiplexed again in the array waveguide grating a1 (100) to be outputted with the output number N / 2, and the optical fiber amplifier j1 (33) outputs the optical signal to the array waveguide grating. Compensate for the loss incurred by passing a1 (100) twice. The loss-compensated optical signal is continuously transmitted to the next optical branch coupling device through the optical path h1 63 after passing the bar 2x2 optical switch e1 33.

In normal operation, the state of the 2x2 optical switch f1 (41) is maintained at a bar so that the monitoring channel wavelength λ _N is transmitted through the array waveguide grating a1 (100) through the optical path h1 (63) and positioned next. The monitoring channel λ _N sent from the optical branch coupling device located before the optical line g1 61 is detected by the optical detector k1 51 in normal operation.

On the other hand, in the counterclockwise ring, wavelengths λ ' _{N / 2 + 1} to λ' _{N-1, which} are operational channels, travel along a solid line, and wavelengths λ 'to λ' _{N / 2-1, which} are residual traffic channels, Proceed along the dotted line, the path for the spare channels. A monitoring channel for monitoring the ring in the counterclockwise direction, the wavelength λ _'N is past the bar (bar) 1x2 optical switch f2 (42) and an array waveguide grating a2 (200) having a status is sent to g2 (62) to the beam . The monitoring channel [lambda] ' _N sent before the optical path h2 64 is detected by the photodetector k2 53 in normal operation.

4 is a configuration diagram when an error occurs in an optical line installed between the optical branch coupling devices in the two-wire bidirectional line switching ring network constituted by the optical branch coupling device of the present invention. In particular, FIG. 4 (a) is an operating state of the optical branch coupling device located immediately to the right of the optical fiber in which an abnormality occurs. FIG.

Referring to Fig. 4 (a), it is a configuration diagram of the optical branch coupling device located immediately to the right of the optical path where the abnormality has occurred, which is the case where the abnormality occurs in the optical lines g1 61 and g2 62. In this case, the monitoring channel is not detected by the photodetector k1 51.

Using the above information, the 2x2 optical switches d1 (21) and d2 (22) constituting the ring switch are converted into a cross state, and all the 2x2 optical switches c1 (12) and c2 used for the remaining traffic channels are used. 14 converts to a bar state, and the 1x2 optical switch f2 42 to provide a path of the supervisory channel of the counterclockwise ring transitions to a cross state.

At this time, the operation is the 2x2 optical switch d1 (21), d2 (22 ), c1 (12), c2 (14) and the 1x2 optical switch f2 (42) switching the operating channel of the counterclockwise ring Convert λ _'N of _{/ 2 + 1} to λ ' _N-1 are looped back and are incident on port number N / 2 of the arrayed waveguide grating a1 (100), and the optical signal travels along the path for the spare channel of the arrayed waveguide grating a1 (100). It is then coupled to the operating channels λ ₁ to λ _{N / 2-1} of the clockwise ring and output to port number N / 2 of the arrayed waveguide grating a1 (100).

Thus, just when the abnormality in the optical line on the left side occurs photodetector k2 (53) only from monitoring the channel is detected, the monitoring channels λ _'N is a 1x2 optical switch f2 (42) in the counterclockwise direction of the optical branch coupling device into a cross Since the light is converted into the cross state, it is not incident on the array waveguide grating a2 (200), but passes through the 2x2 optical switch d2 (22) that is converted to the cross state. It is used to monitor recovery.

When the abnormal optical path is restored again, the monitoring channel is detected by the photodetector L1 (52), and the 2x2 optical switches d1 (21) and d2 (22) are used to restore the optical path of the bidirectional ring to the normal state using the information. ), c1 (12), c2 (14) and 1x2 optical switch f2 (42) are voltage-driven to return to the original state.

Referring to FIG. 4 (b), it is a block diagram of the optical branch coupling apparatus located immediately to the left of the optical path in which the abnormality has occurred, and is a case where the abnormality has occurred in the optical lines h1 63 and h2 64.

In this case, the monitoring channel is not detected by the photodetector k2 53.

Using the above information, the 2x2 optical switches e1 and e2 (23, 24) constituting the ring switch are converted into a cross state, and all 2x2 optical switches c1 and c2 (12, 14) used for the remaining traffic channels are converted. Is converted to a bar state, and the 1x2 optical switch f1 14 for providing a path of the supervisory channel of the counterclockwise ring is converted into a cross state.

Operation at this time is the 2x2 optical switch e1 (23), e2 (24 ), c1 (12), c2 (14) and the working channel of the clockwise ring switch converts the 1x2 optical switch _{f1 (41) λ 1 ~ λ} N _{/ 2-1} loops back and enters port number N / 2 of the arrayed waveguide grating a2 (200). The optical signal travels along the path for the spare channel of the arrayed waveguide grating a2 (200) and then is combined with the operating channels λ ' _{N / 2 + 1} to λ' _N-1 of the clockwise ring to form the arrayed waveguide grating a2 (200). This is output as port number N / 2. When an abnormality occurs in the optical line located immediately to the right of the optical splitter coupling device, the monitoring channel is detected only in the photodetector k1 (51), and in the clockwise monitoring channel λ _N , the 1x2 optical switch f1 (41) crosses. ) Is not incident on the array waveguide grating a1 (100) but passes through the 2x2 optical switch e1 (23), which is converted to the cross state, and then enters the optical path h1 (63) where the abnormality occurs, and then recovers the optical path again. It is used to monitor whether or not.

If the abnormal path is restored, the monitoring channel is detected by the photodetector l2 (54), and 2x2 optical switches e1 (23) and e2 () are used to restore the optical path of the bidirectional ring to the normal state using this information. 24), c1 (12), c2 (14) and 1x2 optical switch f1 (41) are driven in voltage to their original state.

The use of the device of the present invention has the advantage that it is possible to provide a continuous optical transmission service even if an error occurs in the optical path in the two-wire bidirectional line switching ring network.

An object of the present invention is to provide an optical branch coupling device for a two-wire bidirectional line switching ring network capable of providing continuous service even when an optical path abnormality occurs by distinguishing optical paths of an operating ring and a preliminary ring using wavelength division characteristics. It is done.

Claims (5)

NxN array waveguide means used as optical multiplexing and optical demultiplexing means, 2x2 optical switching means for branching / combining or passing a plurality of input signals depending on whether there is an abnormality in the optical line, and whether or not there is an abnormality in the optical line First 1x2 optical switching means for providing a monitoring channel path of the clockwise ring, second 1x2 optical switching means for providing a monitoring channel path of the clockwise ring with or without an optical path, and optical or the waveguide means Optical fiber amplifying means for compensating for losses occurring in the optical fiber coupling means for the two-wire bidirectional line switching ring network, characterized in that consisting of the optical detection means for detecting the monitoring channel in accordance with the presence or absence of the optical line. 2. The apparatus of claim 1, wherein the NxN arrayed waveguide means comprises a plurality of multiplexed or demultiplexed input optical signals operating in a clockwise or counterclockwise ring, the path for the operational channel and the path for the reserve channel. An optical branch coupling device for a two-wire bidirectional line switching ring network, characterized in that the installation. 2. The apparatus of claim 1, wherein the 2x2 light diverting means comprises a plurality of first 2x2 light diverting means for regulating the branching / coupling or passage of the operating channel in a clockwise or counterclockwise ring, and a clockwise or counterclockwise ring. A plurality of second 2x2 optical switching means for regulating the branching / combining or passing of the remaining traffic channels at < RTI ID = 0.0 > and < / RTI > a plurality of third 2x2 constituting a ring switch used for looping back the clockwise operating channel counterclockwise. Optical switching means and a plurality of fourth 2x2 optical switching means constituting a ring switch for use in looping clockwise the operating channel running counterclockwise; Branch coupling device. 2. The optical detection apparatus according to claim 1, wherein the optical detection means includes a plurality of optical detection means for detecting a monitoring channel when there is no abnormality in the optical line and not detecting when the abnormality occurs, and a monitoring channel when the optical line recovers after an abnormality occurs. An optical branch coupling device for a two-wire bidirectional line switching ring network, comprising: a plurality of light detecting means to be detected. According to claim 1 or claim 3, wherein the 1x2 light switching means or the third or fourth 2x2 light switching means operating in the bar state in the normal operation to pass the input signal, the abnormality in the optical line on the left side If so, the fourth 2x2 light switching means operates in the cross state, the second 2x2 light switching means operates in the bar state, and the first 1x2 light switching means operates in the cross state, When the abnormality occurs, the third 2x2 light switching means operates in the cross state, the second 2x2 light switching means operates in the bar state, and the second 1x2 light switching means operates in the cross state. Optical branch coupling device for 2-wire bidirectional line transfer ring network.