KR19980048476A - Optical branch coupling device for two-wire bidirectional line transfer ring network - Google Patents

Abstract

The present invention relates to an optical branch coupling device for a two-wire bidirectional line switching ring network, comprising: an N × N array waveguide means used as an optical multiplexing and optical demultiplexing means, and a plurality of signals inputted according to an abnormality of an optical line. 2x2 optical switching means for branching / combining or passing through; 1st 2x2 optical switching means for providing a monitoring channel path of a counterclockwise ring irrespective of the presence or absence of an optical line; Second 1 × 2 optical switching means for providing a monitoring channel path of the clockwise ring without; and optical fiber amplifying means for compensating for losses occurring in the optical path or the waveguide means; It is composed of a light detecting means to be detected, it is possible to provide a continuous light transmission service even if an error occurs in the optical path in the two-wire bidirectional line switching ring network.

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 separate tracks for operation and two 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 preference, the optical path is looped back using the ring switch, and then the opposite direction to the optical path for the reserve channel is performed. 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 N × N array waveguide grating,

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

3 is a configuration diagram of an optical branch coupling device for a two-wire bidirectional line switching ring network in a normal state according to an embodiment of the present invention;

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 exemplary embodiment of the present invention.

* Description of the symbols for the main parts of the drawings *

a1 (100): array waveguide grating for clockwise ring

a2 (200): array waveguide grating for counterclockwise ring

b1 (11): 2 × 2 optical switch to control branching / combination or passage of the operating channel in a clockwise ring

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

c1 (12): 2 × 2 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 the counterclockwise ring

d1 (21) and d2 (22): 2 x 2 optical switches for the configuration of the ring switch used when looping back the operating channel running in the counterclockwise direction

e1 (23) and e2 (24): 2 x 2 optical switches for constituting a ring switch used when looping back an operating channel clockwise

f1 (41): 1 × 2 optical switch used to advance the monitoring channel clockwise at all times, regardless of the presence or absence of an optical line

f2 (42): 1 × 2 optical switch used to advance the monitoring channel counterclockwise at all times with or without optical path

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

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

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

i2 (34): fiber optic amplifier to compensate 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 to compensate for losses in array waveguide grating a2 (200)

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

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

l1 (52): An optical detector in which a monitoring channel is detected when an error occurs in the optical path 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 includes an N × N array waveguide means used as an optical multiplexing and optical demultiplexing means, and an input branch / splits a plurality of signals depending on whether an optical line is abnormal. 2 x 2 light switching means for coupling or passing, first 1 x 2 light switching means for providing a monitoring channel path of a counterclockwise ring with or without an optical line, and with or without an optical line Second 1 × 2 optical power supply means for providing a monitoring channel path of the directional ring, optical fiber amplification means for compensating for losses occurring in the optical path or the waveguide means, and a monitoring channel is detected depending on whether there is an abnormality in the optical path Light detection means.

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 abnormality 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 is capable of being transmitted by the path for the spare channel of the counterclockwise ring, and the operating band of the counterclockwise ring is capable of being 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.

1 is a configuration diagram of an N × N array waveguide grating, FIG. 2 is a configuration diagram of a 2 × 2 optical switch, and FIG. 3 is an optical diagram for a two-wire bidirectional line switching ring network in a steady state according to an embodiment of the present invention. 4 is a configuration diagram of a branch coupling device, and FIG. 4 is a configuration 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, an N × N arrayed waveguide grating (AWG) having N input and output ports each having a number of input / output ports is an optical device for wavelength division multiplexing by fabricating a waveguide type diffraction grating using well-developed silica technology. If the wavelength division multiplexed light source (λ ₁ to λ _N ) corresponding to the transmission characteristics of the arrayed waveguide grating is input to the input port N / 2 of the N × N array waveguide grating having N input ports and N output ports, the array is arranged. In the waveguide grating, the light sources are separated 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 matching the transmission characteristics of the arrayed waveguide grating are input to the input ports corresponding to the numbers of the respective wavelengths, the N × N array waveguide gratings are combined into one within the arrayed waveguide gratings to form N of the output ports. Only output as / 2.

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 2 × 2 optical switch driven by a voltage can be seen. The state of 2 × 2 includes a basic state 300, a state 400 in which no voltage is applied, and a voltage. There is a cross state 500 that is applied.

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

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 a light source for monitoring an abnormality of an optical fiber line connected between optical branch coupling devices forming a ring network. It is used for input / output of (λN), and the remaining input / output ports connect the same numbers in a loop-back type with the center of a 2 × 2 optical switch b1 (11) or b2 (13).

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

In the clockwise ring, the wavelength λ ₁ to λ _{N / 2-1} is the operating band, and the wavelength λ _{N / 2 + 1} to λ _N-1 is the spare band, and in the clockwise ring the wavelength λ ' _{N / 2 + 1} λ ′ _N-1 is the operating band and wavelength λ ′ ₁ λ ′ _{N / 2-1} is the reserve band. In this case, the wavelengths λ _{N / 2 + 1} to λ _N-1 in the clockwise ring are used to transmit and receive the low priority residual traffic (extratracfic) channel using the preliminary path of the clockwise ring, and the wavelength λ in the counterclockwise ring. ₁ to λ _{N / 2-1} are used to transmit and receive the remaining traffic channel using the reserved 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, an optical signal multiplexed by N-1 wavelengths (λ ₁ , ..., λ _{N / 2-1} , λ _{N / 2 + 1} , ... λ _N ) transmitted through the optical fiber line g1 61 in a clockwise ring. Compensates for the losses experienced in the optical path by passing through the optical fiber amplifier i1 (31), wherein the optical signal compensated for the loss passes through the 2 × 2 optical switch d1 (21) in the bar state and then the arrayed waveguide grating a1. It enters port number N / 2 of (100).

The respective wavelengths are demultiplexed in the array waveguide grating so that the operational 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 2 × 2 optical switch b1 (11) applies a voltage to the channel to be branched / coupled among the operating channels to make the switch state cross, and if it is to continue to pass, the switch state is changed. (2) and 2x2 optical switch c1 (12) also applies a voltage to the channel to branch / combine among the remaining traffic channels to cross the state of the switch and continue to pass it. Maintains the state of the switch as a bar.

In this way, the channel that is passed through the branched coupling device and the newly combined channel are multiplexed again in the array waveguide grating a1 (100) and outputted to 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 2 × 2 optical switch e1 33.

In normal operation, the state of the 2 × 2 optical switch f1 (41) is kept at a bar, and the wavelength λ _{N which} is a monitoring channel is transmitted through the optical waveguide h1 (63) through the array waveguide grating a1 (100). The monitoring channel λ _N sent from the optical branch coupling device located before the optical line g1 61 is detected by k1 51 during light detection in normal operation.

On the other hand, in the counterclockwise ring, wavelengths λ ' _{N / 2 + 1} to λ' _{N-1, which} are operating channels, follow a path drawn by solid lines, and wavelengths λ ' ₁ to λ' _{N / 2-1} , which are residual traffic channels. Proceed along the dashed line, which is the path for this spare channel. Having counter-clockwise direction of the monitor channel wavelength λ _'N to monitor the ring is a bar (bar) state to the 1 × 2 optical switch f2 (42) and an array waveguide grating a2 g2 (62) over the 200 to the beam Is sent. 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 composed of the optical branch coupling device of the present invention. In particular, Figure 4a is an operating state of the optical branch coupling device located immediately to the right of the optical fiber that has an abnormality, Figure 4b is an operating state of the optical branch coupling device located immediately to the left.

Referring to FIG. 4A, a configuration diagram of the optical splitting apparatus located immediately to the right of an optical path where an abnormality occurs is a case where an abnormality occurs in the optical paths 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 2x2 optical switches c1 (for the remaining traffic channels) are used. 12) and c2 (14) convert to a bar state, and the 1x2 optical switch f2 (42) to provide the path of the supervisory channel of the counterclockwise ring switches the cross state.

At this time, the operation is performed by switching switching of the 2x2 optical switch d1 (21), d2 (22), c1 (12), c2 (14) and 1x2 optical switch f2 (42). The channels λ'N _{/ 2 + 1} to λ'N _-1 are looped back and are incident on the port number N / 2 of the arrayed waveguide grating a1 (100), and the optical signal is port number N / of the arrayed waveguide grating a1 (100). 2, the optical signal travels along the path for the spare channel of the arrayed waveguide grating a1 (100), and is combined with the operating channels λ ₁ to λ _{N / 2-1} of the clockwise ring to form the arrayed waveguide grating a1 (100). ) Is displayed as port number N / 2.

Thus when such an error occurs in the optical cable located directly to the left of the optical branch coupling device photodetector k2 (53) only in the monitoring channel is detected, monitoring channels in the counterclockwise direction λ _'N is a 1 × 2 optical switch f2 (42) Is converted to the cross state, and the light beam passes through the 2 × 2 optical switch d2 (22), which is converted to the cross state without entering the array waveguide grating a2 (200). It is incident and used to monitor whether the beam is restored.

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

Referring to FIG. 4B, this is a configuration diagram of the optical branch coupling device located immediately to the left of the light path in which the abnormality has occurred, in which an 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 used for the remaining traffic channels are used. (12, 14) converts to the bar state, and the 1x2 optical switch f1 (41) for improving the path of the supervisory channel of the counterclockwise ring is converted to the cross state.

At this time, the switching of the 2 × 2 optical switches e1 (23), e2 (24), c1 (12), c2 (14) and 1 × 2 optical switch f1 (41) is performed by the operation channel λ of the clockwise ring. ₁ to lambda _{N / 2-1} are looped back and are incident on the 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 a (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). The port number N / 2 is displayed. 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 1 × 2 optical switch f1 (41) crosses. Since it was converted to the cross state, it was not incident on the array waveguide grating a1 (100), but was incident on the h1 (63) by the light beam passing through the 2 × 2 optical switch e1 (23) that was converted to the cross state. It is used to monitor whether the beam is restored.

If the abnormal path is restored, the monitoring channel is detected by the photodetector 12 (54), and using this information, the 2 × 2 optical switch e1 (23), in order to restore the optical path of the bidirectional ring to the normal state, e2 (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 splitting coupling device for a two-wire bidirectional line switching ring network capable of providing a continuous service even in the event of an abnormality in an optical path by distinguishing an operating ring, a reserve ring, and an optical path using wavelength division characteristics. It is done.

Claims (5)

N × N array waveguide means used as light multiplexing and light demultiplexing means, 2x2 light switching means for branching / combining or passing the plurality of signals input according to the abnormality of the optical line, First 1 × 2 light switching means for providing a monitoring channel path of the counterclockwise ring with or without an optical path; 11 x 2 light switching means for providing a monitoring channel path of the clockwise ring with or without an optical path; Optical fiber amplifying means for compensating for losses occurring in the optical line or the waveguide means; An optical branch coupling device for a two-wire bidirectional line switching ring network, comprising: optical detection means for detecting a monitoring channel according to an abnormality of an optical line. The waveguide device of claim 1, wherein the N × N array waveguide means A two-wire bidirectional line switching network comprising a plurality of multiplexed or demultiplexed input optical signals operating in a clockwise or counterclockwise ring and providing a path for an operating channel and a path for a spare channel. Optical branch coupling device for The method of claim 1, wherein the 2 × 2 light conversion means A plurality of first 2 × 2 light switching means for regulating the branching / combining or passage of the operating channel in a clockwise or counterclockwise ring; A plurality of second 2x2 optical switching means for regulating the branching / combining or passing of the residual traffic channels in the clockwise or counterclockwise ring; A plurality of third 2x2 light switching means constituting a ring switch used when looping back the operating channel running in a clockwise direction counterclockwise; An optical branch coupling device for a two-wire bidirectional line switching ring network, comprising a plurality of fourth 2x2 optical switching means constituting a ring switch used for looping back an operating channel counterclockwise. . The method of claim 1, wherein the light detecting means A plurality of light detecting means for detecting a monitoring channel when there is no abnormality in the optical line and not detecting when an abnormality occurs; An optical branch coupling device for a two-wire bidirectional line switching network, comprising a plurality of optical detection means for detecting a monitoring channel when an abnormality occurs in an optical line and is restored. The method of claim 1 or 3, wherein the 1x2 light switching means or the third or fourth 2x2 light switching means For normal operation It operates in bar state and passes the input signal, When an error occurs on the left optical line The fourth 2x2 light switching means operates in a cross state, The second 2x2 light switching means are all operated in a bar state, The first 1 × 2 light switching means operates in a cross state, When an error occurs in the optical line on the right The third 2x2 light switching means operates in a cross state, The second 2x2 light switching means are all operated in a bar state, And said second 1 × 2 light switching means operates in a cross state.