KR100340726B1 - A watching device of automatic laser shutdown for reverse optical link - Google Patents

Abstract

In the optical communication system for transmitting an optical signal through an optical cable, the present invention detects a defect occurrence point and automatically shuts off a light source at a corresponding point when a defect occurs, such as disconnection or breakage of an optical cable line, removal or opening of an optical connector. Automatic light source blocking, and automatic recovery upon defect removal. In particular, the automatic light source blocking can be executed and restored by the reverse optical link monitoring channel regardless of the optical transmission system operating environment and the type of optical transmission network. An optical signal generator for converting the electric data signal to be transmitted into a predetermined optical wavelength signal and outputting the optical signal; a transmission optical amplifier for amplifying the optical wavelength data signal applied from the optical signal generator to an appropriate level signal; The optical wavelength data signal applied from the optical amplifier is applied to the optical cable and output. An optical demultiplexer which separates and extracts a supervisory control signal of another optical wavelength applied in the reverse direction from the optical cable and outputs it to another path, and receives an optical wavelength supervisory control signal output from another optical path from the optical demultiplexer to another path and converts it into an electric signal. And a control signal receiving unit for outputting the control signal receiving unit and a monitoring control unit for processing the supervisory control signal received from the control signal receiving unit to determine and notify the disconnection of the optical cable.

Description

A WATCHING DEVICE OF AUTOMATIC LASER SHUTDOWN FOR REVERSE OPTICAL LINK}

In the optical communication system for transmitting an optical signal through the optical cable, the present invention provides a point of occurrence of a defect at the time of occurrence of a defect such as a cut or break of an optical cable line, or the removal and opening of an optical connector. Automatic Laser Shutdown (ALS) which detects and automatically cuts off the laser-generating light source at the corresponding point, and automatically recovers when the defect is removed. In particular, the optical transmission system operating environment and the type of optical transmission network Regardless, the automatic light blocking (ALS) can be executed and restored by the reverse optical link monitoring channel.

Skin and eyes that are easily exposed to installation and maintenance personnel from the laser, which is a high power light source, when cutting or cutting the optical fiber line or opening of the optical cable connector in the optical communication system To protect the system and to restore the performance of the system quickly.

The copper (Cu) communication line, which is a general line used for communication such as a telephone, is not only vulnerable to moisture but also has a high possibility of data distortion or loss due to external factors such as static electricity or a short circuit. Without the same problem, there is an advantage that the long-distance transmission of data with less power.

An optical communication system using the optical communication line as described above uses one optical communication optical fiber cable line to process and transmit communication data having a capacity equivalent to about 2,000 to 30,000 times or more of a regular copper (Cu) telephone line subscriber line. In addition, due to the ability to reduce the cost of the facility due to the ability to communicate more long-distance, the use is gradually increasing.

Therefore, the maintenance for the normal operation of the large-capacity optical communication line as described above is very important, in particular, the failure such as open or cut in the optical cable (Optical Cable), or open the connector for connecting the optical cable for maintenance In this case, the international safety standard (IEC 825-1, 2) prevents damage to the skin or eyes of maintenance personnel by a high power laser for transmitting an optical signal. It is enacted and applied.

Hereinafter, an automatic light source blocking device according to the prior art will be described with reference to the accompanying drawings.

1 is a configuration diagram of an automatic light source blocking device of an optical communication system according to the prior art, and FIG. 2 is a flowchart of an automatic light source blocking method according to the prior art.

Referring to FIG. 1 as described above, a light source blocking device according to the prior art will be described. A caller is subscribed, has a plurality of channels for optical communication, and transmits and receives an optical signal for each channel. NE (Network Element) 10,

A plurality of optical cables 15 to 19, 25 to 29, which are optical transmission lines for transmitting optical signals transmitted and received for each of a plurality of channels from the first optical end station 10;

An optical fiber amplifier (OFA), which is placed between the plurality of optical cables 15 to 19 and 25 to 29, receives, amplifies and outputs a weak optical signal in the process of being transmitted through the optical cable. A plurality of optical relay stations 30, 40, 50, and 60, each of which is composed of first to fourth optical relay stations,

A plurality of subscribed callees are connected, and a plurality of channels for optical communication are included, and each channel is composed of a second optical element station (NE) 20 for transmitting and receiving a corresponding optical signal.

The automatic light source blocking (ALS) sequence according to the above-described prior art configuration is that the corresponding optical cable lines 15 to 19, 25 to 29 connected to the respective optical repeaters 30, 40, 50, and 60 are cut off. Or an optical signal is not input to the optical amplifiers of the corresponding optical relay stations 30, 40, 50, and 60 because the optical cable connector is opened for maintenance and disconnected. A first step (S1) of determining whether a loss of signal (LOS) state is continuously detected for a predetermined time;

In the first step (S1), when the LOS signal is continuously detected for a predetermined time, the light source for generating the optical communication signal of the corresponding optical amplifier 32, 42, 52, 62 that outputs the optical signal is automatically cut off. A second step S2 of an ALS (Automatic Laser Shutdown) control signal generation request requesting

If there is a request for the generation of the ALS control signal according to the second step S2, the high power optical signal generation and transmission (Tx) laser of the corresponding optical amplifiers 32, 42, 52, and 62 (LASER) A third step S3 of determining whether the light source is defective,

As a result of the determination in the third step S3, when there is no defect in the Tx light source for transmitting the high power optical signal, the Tx light source for operating the high power optical signal is operated. A fourth step S4 of performing ALS control according to an Automatic Laser Shutdown (ALS) request signal,

After stopping the operation of the high power laser light source by the fourth step (S4), the step (S5) for generating an alarm indicating the LOS generation and the operation stop state of the laser light source.

Hereinafter, with reference to the accompanying drawings the operation of the prior art of the configuration as described above will be described in detail.

Among the plurality of optical paths, as an embodiment, the optical path 17, which is a transmission line of a signal transmitted from the second optical relay station 40, has been cut by an accident or the like, or by an operation operator, the optical cable When the connection of the connector is released and the connection is opened, the corresponding transmission optical amplifier 52 connected to the corresponding channel CH A of the third optical relay station 50 is connected to the second optical relay station 40. A state in which an optical signal is not received from the transmission optical amplifier 42, that is, a state of loss of signal (LOS) is sensed, and the control unit of the third optical relay station 50 not illustrated in the figure The detected LOS status information is applied as shown in FIG.

The control unit of the third optical relay station 50 determines whether the LOS signal lasts for a predetermined time defined by International Standards (ITU-T, G.958) (S1).

As a result of the determination (S1), if the LOS signal continues for a predetermined time, the control unit of the third optical relay station 50, the laser constituting the transmission optical amplifier 42 of the second optical relay station 40. The ALS (Automatic Laser Shutdown) request signal for blocking the operation of the light source is applied to the optical amplifier 55 for receiving the corresponding channel CH A of the third optical relay station 50 and via the optical cable 27 which operates normally. The second optical relay station 40 is applied to the corresponding receiving optical amplifier 45 (S2).

The control unit, not shown in the drawing of the second optical relay station 40, receives the ALS signal applied from the control unit of the third optical relay station 50, analyzes the optical amplifier for transmission of the corresponding channel CH A. (42) The state is checked to determine whether the high power laser light source operates normally or is defective (S3).

As a result of the determination (S3), when the laser light source of the transmitting optical amplifier 42 does not have a defect and operates normally, the operation stops the laser light source so as not to generate a laser light signal. (S4), and send a corresponding alarm signal such as the place where the defect or failure occurred and the type of failure to the central management unit (NMS: Network Management System) of the optical system for maintenance and operation. Ensure that personnel are able to take the necessary repair measures immediately.

Therefore, when the maintenance operation personnel arrives at the site where the defect of the optical cable 17 occurs for repair and repair, the cut or open portion of the optical cable 17 is opened through a high power laser light source. The laser light source output from the connection portion of the open optical cable connector does not damage the skin or eyes of the operator.

However, in the prior art as described above, when the occurrence of a defect in the optical path occurs simultaneously at the reverse point of the communication channel, the ALS request control signal is not transmitted in the reverse direction, so that a high-power laser generated from the optical amplifier Not only was there a problem that the light source could not be shut off automatically, but even if the operating personnel repaired and repaired a defective optical cable line, there was a problem that the output of the laser light source could not be automatically restored normally.

As another prior art which partially improves the problems of the prior art, according to Patent Application No. 99-39416, an optical cable is cut or broken, or an optical connector is opened by an operator. In this case, the laser generator cannot be operated by confirming that the optical cable is cut or damaged by receiving a signal transmitted from the optical laser of the transmitting side and partially reflected from the end face of the damaged optical cable (Shut Down). ALS control was performed.

However, the above-described technique is a problem in which the broken end surface of the optical cable is uneven or the optical signal is spread, that is, the optical cable breakage or the opening of the optical connector at a point where the span loss is large is increased. The detection amount of the signal was so weak that it was unable to detect the breakage of the optical cable or the opening of the optical connector, and the ALS control could not be executed.

As another embodiment of the prior art, there is a technology using a data communication channel (DCC) channel, which is a data channel, but this is based on the premise that a DCCr (DCC Receive) channel and a DCC-SV (DCC Supervising) channel are operating normally. If the optical cable is cut or broken or the optical connector is open, DCC channel that performs one-to-one communication does not work properly and therefore cannot perform ALS control. there was.

The present invention divides an optical communication signal into a data optical signal for a data channel and a fault monitoring optical signal for a fault monitoring channel, and uses different optical wavelengths, and a reverse optical link is used so that the directions transmitted using the same optical cable are opposite to each other. By providing a control unit for monitoring the faults in each optical cable section, it is possible not only to accurately identify the fault occurrence section, but also to provide an automatic light source blocking device by monitoring the reverse optical link to simplify the algorithm. For that purpose.

In order to achieve the above object, the present invention is an optical communication system consisting of a plurality of optical end stations and optical relay station, and transmitting and receiving data signals as optical signals through an optical cable, the optical end station and the optical relay station; An optical signal generator for converting a data signal to be transmitted into an optical data signal having a predetermined wavelength and outputting the optical signal; A transmission optical amplifier for amplifying the optical wavelength data signal applied from the optical signal generator into an optical signal having an appropriate level; An optical demultiplexer which applies and outputs an optical wavelength data signal applied from the transmission optical amplifier to an optical cable and simultaneously extracts and extracts an optical signal for monitoring and control of a different wavelength applied in a reverse direction from the optical cable and outputs it to another path; A control signal receiver which receives the optical wavelength signal for monitoring and control output from the optical demultiplexer and converts the optical wavelength signal into an electrical signal and outputs the converted electrical signal; And a supervisory control unit which processes the supervisory control signal received from the control signal receiver to determine whether the optical cable is disconnected and notifies the centralized management device of the determination result.

The present invention also provides an optical multiplexing unit which receives and outputs an optical data signal having a predetermined wavelength received from the optical cable and simultaneously outputs an optical signal having a different wavelength applied to another path in the opposite direction to the optical cable; A reception optical amplifier for amplifying the optical wavelength data signal output from the optical multiplexer into an optical wavelength signal having an appropriate level; An optical signal receiving unit converting the optical wavelength data signal applied from the receiving optical amplifier into an electrical data signal and outputting the electrical data signal; A monitoring control unit for monitoring the disconnection of the optical cable and generating and outputting an electric signal for controlling the optical cable; And a control signal transmitter for converting the supervisory control signal applied from the supervisory control unit into an optical signal having a wavelength different from the received optical wavelength and outputting the optical signal to the optical multiplexer.

1 is a configuration diagram of an automatic light source blocking device of an optical communication system according to the prior art,

2 is a flowchart of a method for automatically shutting off a light source according to the prior art;

3 is a functional block diagram of an optical signal transmission system to which an automatic light source blocking device based on reverse optical link monitoring is added as an embodiment of the present invention;

4 is a functional configuration diagram for explaining the automatic light source blocking device by monitoring the reverse optical link.

** Explanation of symbols on the main parts of the drawing **

10,20: optical end station 15,16,17,18,19,25,26,27,28,29: optical cable

30, 40, 50, 60: optical relay station 111, 121: optical signal generator

32,42,52,62,35,45,55,65,118,138,128,129,139,119: amplifier

112,122,132,132 ': demultiplexer 113,133,133', 123: control signal receiver

114,134,134'124: control signal transmitter 115,125,135: supervisory control

116,126,136,136 ': Multiplexer 117,127: Optical signal receiver

Hereinafter, with reference to the accompanying drawings will be described an automatic light source blocking device by monitoring the reverse optical link of the present invention.

FIG. 3 is a functional block diagram of an optical signal transmission system to which an automatic light source blocking device is added by reverse optical link monitoring as an embodiment of the present invention, and FIG. 4 is a view for explaining the automatic light source blocking device by reverse optical link monitoring. It is a functional configuration for each channel.

Referring to FIG. 3, the apparatus for reverse optical link monitoring automatic light source blocking according to an embodiment of the present invention is configured for each channel to transmit data, thereby transmitting an electrical data signal. Is converted into an optical signal having a predetermined wavelength, that is, an optical signal having a wavelength of 1550 nm as an embodiment, and is outputted. The optical signal generator includes a laser diode ( 111),

In order to transmit the optical wavelength data signal of 1550 nm received from the optical signal generator 111 at a long distance, as an example, an appropriate level to allow the data signal to be transmitted through a long distance optical cable of about 160 Km long A transmission optical amplifier (BA) 118 for amplifying and outputting the optical signal at (Level);

The optical data signal of 1550 nm wavelength applied from the transmission optical amplifier 118 is outputted to be transmitted through the 160 Km optical cable 15 and at the same time of another wavelength applied by the reverse optical link from the optical cable 15. An optical signal, for example, a wavelength division multiplexing (WDM) 112 for separating and extracting an optical wavelength signal of 1310 nm and outputting the optical signal in a corresponding reverse path;

A control signal receiver 113 for converting and outputting a 1310 nm wavelength supervisory control optical signal extracted and extracted from the demultiplexer 112 into an electrical signal and outputting the electrical signal;

The control signal receiving unit 113 converts the electric signal into an electric signal and processes the applied supervisory control signal to determine whether the optical cable 15 is cut, broken or open, and the result is determined. It includes a monitoring control unit 115 for transmitting and displaying to a central management device (NMS: Network Management System) not shown in the accompanying drawings, each optical station (10, 20) and optical relay station (30, 40, A corresponding transmitter for each channel of 50 and 60 is configured.

That is, the transmitter having the above configuration has the same configuration in all the channel receivers of the first optical end station 10 and the second optical end station 20, and the first to fourth optical relay stations 30, 40, 50 and 60. In the above, a plurality of similar configurations are provided, and only one monitoring controller is provided.

In addition, the present invention, for example, detects and outputs an optical data signal that is applied as a 1550 nm optical wavelength signal through the optical cable 19 and at the same time an optical signal of another wavelength applied to the reverse optical link, as an example An optical multiplexer (WDM: Wavelength Division Multiflexing) 126 receiving a 1310 nm wavelength optical signal for supervisory control and outputting the optical signal to the optical cable 19 in a reverse direction;

A reception optical amplifier (PA) 128 for amplifying a data optical signal having a wavelength of 1550 nm applied from the optical multiplexer 126 into an optical wavelength signal having an appropriate level, and outputting the amplified data optical signal;

An optical signal receiver 127 which receives an optical signal having a wavelength of 1550 nm and then converts the electrical signal into an electrical signal after being amplified from the reception optical amplifier 128;

A supervisory control unit 125 which generates and outputs a supervisory control signal that can determine whether the optical cable 19 is cut or broken as an electrical signal and simultaneously performs the function of the supervisory control unit 115;

In an embodiment, the control signal transmitter 124 converts a signal for monitoring control received from the monitoring controller 125 into an optical signal having a wavelength of 1310 nm and outputs the optical signal to the optical multiplexer 126. And constitute a specific channel signal receiver of each optical station 10, 20 and optical relay station 30, 40, 50, 60.

That is, the receiver has the same configuration in all the channel receivers of the second optical end station 20 and the first optical end station 10, and is similar in the first to fourth optical relay stations 30, 40, 50, and 60. A plurality of configurations are provided, and only one monitoring control unit is provided.

Hereinafter, the automatic light source blocking device by monitoring the reverse optical link having the above configuration will be described in detail with reference to FIGS.

When the first optical station 10 and the second optical station 20 and the first to fourth optical relay station (30, 40, 50, 60) has a fatal trouble in the operation device, The redundant configuration is provided with a spare device that can operate in place, the switching to the spare device (Switching) is switched by the control of the central management unit (NMS) not shown in the figure is operated.

The optical signal generator 111 of the first optical end station 10 converts an electrical data signal for each channel to be transmitted into an optical signal having a wavelength of 1550 nm as an embodiment, and transmits a booster amplifier (BA). 118 is amplified into an optical wavelength signal of an appropriate level and then applied to the demultiplexer 112.

The demultiplexer 112 transmits the optical signal having a wavelength of 1550 nm to the first optical relay station 30 by applying it to the optical cable 15 having a length of 160 Km.

Demultiplexer 132 ′, 132 and second light by a plurality of optical relay stations 30, 40, 50, 60 having the same function, including demultiplexer 112 of the first optical end station 10. The demultiplexer 122 of the station 20 is for monitoring control of a 1310 nm wavelength applied to the reverse optical link from the multiplexer 136 of the first optical relay station 30 or the multiplexer 126, 116, 136 'having the same function. The optical signal is applied, separated and applied to the control signal receivers 113, 133, 133 ', and 123, respectively.

The corresponding control signal receivers 113, 133, 133 'and 123 convert the 1310 nm wavelength supervisory control optical signal applied to the reverse optical link into an electric signal and then apply the signal to the corresponding supervisory control unit 115, 135 and 125. The controllers 115, 135, and 125 analyze the applied signals, respectively, and determine whether the optical cables 15 to 19, 25 to 29 connected to the corresponding channels are cut, broken, or open. In addition, the resultant signal is notified to the NMS not shown in detail in the drawing, so that the operating personnel can immediately identify a failure area by performing the processing of the NMS and immediately perform a corresponding action required.

In addition, an optical signal having a wavelength of 1550 nm, which is generated from the optical signal generating unit 111 and applied through corresponding optical cables 15 to 19, 25 to 29, having a length of 160 Km, is the corresponding multiplexer 136, 126, 136. ', 116, respectively, are applied to and received by the multiplexer, and then applied to a corresponding Post Amplifier (PA) (138, 128, 139, 119), respectively, and amplified into an optical signal of an appropriate level. The optical signal receivers 127 and 117, which are transmission destinations, are converted into electric signals or applied to the corresponding demultiplexers 132 of each optical relay station, and are transmitted to the transmission destinations through the corresponding optical cables.

The monitoring control unit 125 has the same function and configuration as the monitoring control unit 115 and the monitoring control unit 135 of each optical relay station, and according to the embodiment, corresponding optical cables 15 to 19 and 25 to 160 Km long are provided. 29) generates a control monitoring signal that can determine whether the cut, break or open is applied to the corresponding control signal transmitter (124, 134, 134 ', 114).

The control signal transmitters 124, 134, 134 ', and 114 respectively convert the supervisory control signals received from the corresponding supervisory control units 125, 135, and 115 into optical signals having a wavelength of 1310 nm, for example. Is applied to ').

Each of the multiplexers 136, 126, 136 ', 116 applies the monitoring control signal to the corresponding 160 Km-length optical cables 15 to 19, 25 to 29 in the reverse direction, so that the corresponding demultiplexers 112, 132', 122, and 132 respectively. After receiving and converting the control signal receivers 113, 133 ', 123, and 133 into electrical signals, and then applying the signals to the corresponding monitoring controllers 115, 135, and 125, the supervisory control unit analyzes and processes the cut or broken optical cables. It checks whether it is broken or open.

Therefore, according to the present invention having the above configuration, it is possible to check the failure, that is, cut or break or open of the optical cable formed in each section by section, and the algorithm for processing is also simplified. can do.

According to the present invention having the above configuration, by transmitting a supervisory control signal for confirming whether the optical cable for each section of the optical signal transmission system is disconnected, damaged or opened through the reverse optical link, it is easy, quick and accurate As a result, the reliability of the system can be improved, and at the same time, there is an industrial use effect that allows the processing algorithm to be configured very simply.

Claims (2)

In an optical communication system comprising a plurality of optical end stations and optical relay stations, and transmitting and receiving data signals as optical signals through optical cables, the optical end stations and optical relay stations, An optical signal generator for converting a data signal to be transmitted into an optical data signal having a predetermined wavelength and outputting the optical signal; A transmission optical amplifier for amplifying the optical wavelength data signal applied from the optical signal generator into an optical signal having an appropriate level; An optical demultiplexer which applies and outputs an optical wavelength data signal applied from the transmission optical amplifier to an optical cable and simultaneously extracts and extracts an optical signal for monitoring and control of a different wavelength applied in a reverse direction from the optical cable and outputs it to another path; A control signal receiver which receives an optical wavelength signal for monitoring and control output from the optical demultiplexer and converts the signal into an electrical signal; Automatic light source by reverse optical link monitoring, characterized in that it comprises a monitoring control unit for processing the monitoring control signal received from the control signal receiving unit to determine whether the optical cable is disconnected or notifies the centralized management device of the determination result. Blocking device The method of claim 1, wherein the optical end station and the optical relay station, An optical multiplexer which receives an optical data signal of a predetermined wavelength applied from the optical cable and simultaneously outputs an optical signal for monitoring and control of another wavelength applied to another path to the optical cable in a reverse direction; A reception optical amplifier for amplifying and outputting the optical data signal applied from the optical multiplexer into an optical data signal having an appropriate level; An optical signal receiver for converting an optical data signal applied from the reception optical amplifier into an electrical data signal and outputting the electrical data signal; A supervisory control unit which monitors the disconnection of the optical cable and generates a signal to perform the corresponding control; And a control signal transmission unit converting the supervisory control signal applied from the supervisory control unit into an optical signal having a wavelength different from the received optical wavelength and outputting the optical signal to the optical multiplexer. Automatic light source blocking device.