KR20130029329A - Distributed optical fiber monitoring device and its method - Google Patents

Abstract

PURPOSE: A distributed control type monitoring method and a measuring device thereof are provided to improve measuring accuracy by reducing a pulse width. CONSTITUTION: An optical line termination devices(105~107) emits monitoring light to an upper direction of a line terminal device. The optical line termination device measures abnormal positions in optical lines. The optical line termination device transmits a measurement result to an electrical communication path. The optical line termination device transmits the received measurement result to a circuit terminal device(101) through the optical line. The circuit terminal device transmits the measured result received from the optical line termination devices to an optical monitoring server connected to an ethernet switch. An optical splitter individually measures the optical lines for a plurality of the optical lines.

Description

Distributed Optical Fiber Monitoring Device And Its Method

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed control optical path monitoring method and a measuring device. More particularly, the present invention relates to a method for measuring and controlling a distributed optical fiber beam. Optical path measuring device using OTDR (Optical Time Domain Reflectometry) technology that detects scattered light or reflected light in the time domain and converts it into distance, and uses it to The present invention relates to the provision of a new distributed control line monitoring method for detecting physical obstacles such as bending and disconnection of optical communication lines.

In the current communication network, all wired transmission media from the backbone to the subscriber network are becoming optical cables, and the maintenance of the optical network is becoming an important factor due to the increasing optical cables and various and complicated optical fiber network structures.

The optical network is PTP (Point To Point) type, ring type, tree type, star type, etc. according to the connection structure of the hub system installed in the central communication room or the center and the node devices connected to the subordinate devices. The optical fiber monitoring system is adopted and used as a means for quick and efficient maintenance by monitoring failures caused by the physical damage to optical fibers constituting the optical network.

The fiber optic monitoring system uses optical switches for specific fiber cores without prejudice to the communication service to the spare optical fiber which is installed only and does not actually transmit optical signals or to the operational optical fiber which is actually transmitting signals for optical communication. After the selective transfer, the laser beam is transmitted in the form of pulses, and the scattered light or reflected light generated from the laser beam is detected in the time domain and converted into distance using OTDR (Optical Time Domain Reflectometry) technology. When the loss of light due to disconnection changes, measure the location and report it to the operator.

In addition, the development section of the optical path and the associated track facilities constituting the optical network are registered and displayed on the GIS map, and the measurement results of the line measuring device (hereinafter referred to as the optical fiber measuring device) using the OTDR technology are displayed in connection with the GIS. It is configured to enable the operator to perform the maintenance work quickly and efficiently.

Recently, PON (Passive Optical Network), an Ethernet-based passive optical network, has been widely spread not only in subscriber networks but also in public office networks.

PON is a technology that implements Ethernet-based bidirectional communication as a tree network structure between end subscribers or end devices based on hub communication devices such as MSPP equipment by using passive optical branch devices that do not use power such as optical splitters.

In the case of a tree optical network where the hub system and the node device are branched through the optical splitter, the insertion loss increases rapidly as the number of branch lines of the optical splitter increases.

For example, a 1 × 8 optical splitter with 8 branch lines has a minimum insertion loss of 9 dB. As the insertion loss increases in the measurement section, the maximum measurement distance occurs in the optical fiber measuring apparatus.

In order to compensate the maximum measuring distance reduced by the insertion loss of the optical splitter, the optical measuring device increases the pulse width of the monitoring light and performs the measurement. When the pulse width of the monitoring light is increased, the maximum measuring distance increases, while the fusion splicing point and the connector are connected. There is a problem that the measurement accuracy for the event of the optical path such as a point is deteriorated.

Increasing the focal length of the magnifying glass allows the observation of a large area, but the same principle is the same as the magnification is lowered and fine objects cannot be observed in detail. This is the measurement limit due to the trade-off of the maximum measurement distance and measurement accuracy in principle for optical measuring devices using OTDR technology.

In addition, when the optical path measuring device is applied to a branched optical device such as an optical splitter, the scattered light and the reflected light from each branching line are mixed into one input optical fiber and flowed into the light receiving part of the optical path measuring device. Analysis of phosphorus waveforms is difficult.

The optical path monitoring method for the tree-type optical network branched into the optical splitter used in the past is installed to circulate the optical fiber line in the closed curve form throughout the monitoring section and operate it as a reserve line for monitoring the optical line or branch line of the optical splitter. It is a method to operate the monitoring system by setting the monitoring section of the light beam until just before.

The former method does not directly monitor the optical splitter network to be monitored, but monitors a spare optical line that circulates the optical splitter network. The method has a disadvantage in that each branch line section branched by the optical splitter cannot be monitored.

Hub communication equipment such as Ethernet COT (Central Office Terminal) starting and end point, and in the case of optical communication network consisting of ring type with remote communication equipment such as Ethernet RT (Remote Terminal) continuously installed, many hubs within relatively short monitoring distance And a telecommunication device adjacent to each other, and have a high section loss of the optical path due to a plurality of optical connectors and fusion splicing.

In this case, it is possible to increase the width of the optical pulse transmitted from the optical fiber measuring device to compensate for the section loss of the optical path, but when the width of the optical pulse increases, the dead zone increases, so that the event on the optical path adjacent to the short distance, that is, the optical connector It is impossible to precisely measure the junction point, the fusion point, and the loss increase point due to bending.

In addition, the conventional optical fiber monitoring system is complicated to install in a rack-mounted cabinet in which a number of accessories such as organically connected optical fiber measuring devices, servers, optical switches, measuring controllers and monitoring filters are integrated in a single rackmount cabinet. Difficulties in operation management due to the system configuration and limitation of installation space have been recognized as problems.

In addition, all the devices that make up the monitoring system are mounted in a single cabinet and operated in a centralized control system, so if any one of the accessories fails, normal operation of the entire monitoring system until the problem is solved. This is not possible and there is a fatal problem that requires the monitoring of the entire section to be suspended.

Accordingly, the present invention has been invented to solve the problems described above, and after the optical fiber measuring apparatus is provided with a remote communication means such as Ethernet distributed and installed in a plurality of arbitrary points in the optical communication network, the operator has a server or integrated management function. Install only the minimum devices that can be carried out in a suitable place, and issue measurement control commands in a bidirectional communication from a plurality of distributed optical fiber measuring devices to collect respective measurement results;

The optical fiber measuring devices distributed at various points within the optical communication network monitor the optical beams for the partial section corresponding to each responsible monitoring section, but the entire optical network monitors the monitoring section without overlapping the adjacent optical measuring device and monitoring section. By appropriately assigning and operating the monitoring zones to be accommodated in the system, it is possible to achieve the objective of overcoming the measurement limits due to the complementarity between the maximum measurement distance and the measurement accuracy and to avoid the blind spots on the entire optical communication network.

The present invention is provided with a remote communication means in the optical fiber measuring apparatus distributed after installation in a plurality of arbitrary points in the optical network, the operator from the distributed optical ray measuring apparatus using only a minimum device capable of performing a server or integrated management function The distributed control optical fiber monitoring method, which allows measurement commands and collects each measurement result through bidirectional communication, reduces the pulse width by narrowing the pulse width because a single optical fiber measuring device monitors a part of a short distance of the entire optical fiber monitoring section. The designer can arrange the optical beam measuring device according to the distribution of insertion loss in the monitoring section so that the monitoring blind spot does not occur.

In addition, the conventional method had a problem that the entire system could not be used in the event of any failure of any of a plurality of accessories constituting the optical monitoring system, whereas the distributed control optical monitoring system was distributed in random locations. Even if a failure occurs in the measuring device, the optical line monitoring is suspended only in the corresponding section, so that normal monitoring is possible in other sections, thereby minimizing the monitoring gap caused by the system failure.

1 is a block diagram showing a passive optical network as an example of an optical communication network to which the distributed control optical path monitoring technology of the present invention can be applied.
FIG. 2 is a block diagram illustrating a distributed control optical path monitoring method to which the technology of the present invention is applied for monitoring the optical path of the passive optical network of FIG.
3 is a block diagram showing a ring optical network as another example of an optical communication network to which the distributed control optical fiber monitoring technology of the present invention can be applied.
4 is a block diagram illustrating a distributed control optical path monitoring method to which the technology of the present invention is applied for monitoring the optical path of the ring optical network of FIG.
5 is a configuration diagram showing an example of an internal configuration of an optical path measuring apparatus of the OTDR method for monitoring a distributed control optical path.
Figure 6 is a block diagram showing another example of the internal configuration of the optical path measurement device of the OTDR system for monitoring the distributed control optical path.
7 is a configuration diagram showing another example of the internal configuration of an optical path measuring device of the OTDR method for monitoring a distributed control optical path.
8 is a configuration diagram showing another example of an internal configuration of an optical path measuring apparatus of the OTDR method for monitoring a distributed control optical path.

Hereinafter, with reference to the accompanying drawings look at a preferred example of the present invention for achieving the above object.

Ethernet-based optical subscriber network is an optical splitter, which is a passive optical device, and a plurality of remote terminals (RTs) are closed curves by optical paths starting from the tree-type optical network 100 that accommodates multiple subscribers and the central office terminal (COT). The ring-shaped optical network 300 connected by is widely used.

The tree-type optical network 100 is deployed through the optical terminal box from the optical line termination (OLT), which is the line terminal device 101, is connected to the optical splitter 103, which is a passive optical power branching element, and branches into N at the optical splitter. An optical network unit (ONU), which is an optical termination device (105, 106, 107), is connected to an end of the conventional optical path, and various field terminal devices are connected to the ONU by electrical communication means.

On the other hand, when the ONU, which is each optical termination device 105, 106, 107, transmits a signal to the line terminal device 101 via the optical splitter 103, each ONU is a line terminal device via one optical line path. When it is designed to reach (101), when disconnection occurs in the optical line connecting the optical splitter 103 and each optical terminator 105, 106, 107, the optical terminator and line terminal device 101 Since communication is interrupted between the terminals, the general tree-type optical network has two components as shown in FIG. 1 and operates in the concept of a main line and a spare line.

That is, each optical terminator 105, 106, 107 is not only connected to the main line terminal device 101 via the optical splitter 103 connected to the main line, but also via the optical splitter 104 connected to the spare line. It can also be connected to the preliminary line terminal device 102 so that when a problem occurs in the optical path connected to the main line is a way to enable communication through the reserve line.

FIG. 2 is a block diagram illustrating a distributed control optical path monitoring method to which the present invention is applied for monitoring the optical path of the passive optical network of FIG. 1. Each line terminal device 201 and 202 includes an optical filter 211, It is connected to each optical splitter via 212, and the optical communication signal arriving from the optical splitter 203 constituting the main line and the optical communication signal arriving from the optical splitter 204 constituting the preliminary line in the optical fiber measuring apparatus 500 After the reception, the optical path measuring device 500 filters the monitoring light signal, uses the measured light signal, and transmits the optical signal received from the remaining main line and the spare line to the optical termination devices 205, 206, and 207.

Meanwhile, the optical fiber measuring apparatus 500 transmits the measurement result to the optical terminal devices 205, 206, and 207 through electrical communication such as Ethernet, and receives the optical fiber measuring result from the optical fiber measuring device 500. The value is converted into an optical signal and transmitted to the line terminal device 201 or 202.

The circuit terminal apparatus 201, 202 transmits the measurement results to the optical fiber monitoring server through the Ethernet switch, and collects the test results of the optical fiber measuring apparatus for each branch line constituting the main circuit and the spare circuit at the end of the optical splitter. Enable integrated management The upward operating light signal from the optical terminators 205, 206, 207 to the line terminal devices 201, 202 is transmitted from the optical filter 503, 504, 602 provided in the optical path measuring device 500. It is combined and proceeds to the line terminal apparatuses 201 and 202 via the optical splitter.

On the other hand, in order to block the monitoring light signal of the optical path measuring device 500 into the line terminal device 201, 202, the optical filter (211, 212) for passing the operating light and blocking the monitoring light is the line terminal device 201, 202 may be provided at the start end, which is the end point of the monitoring section of the actual optical fiber measuring device 500.

The distributed control optical ray measurement apparatus 500 used in the distributed control optical ray monitoring method of FIG. 2 includes an OTDR 501, an optical switch 502, and optical filters 503 and 504, and the optical switch includes a first optical filter ( After switching to the monitoring light input port of the 503, and connecting the operating light from the optical transmission equipment to the first port 505, the monitoring light from the OTDR (501) is combined in the optical filter 503, the second port (506) Will be printed).

After switching the optical switch to the monitoring light input port of the second optical filter 504, and connecting the operating light from the optical transmission equipment to the first port 508, the monitoring light from the OTDR (501) is the optical filter 504 And the output is output to the second port 507. Of course, it can be expanded in the same way depending on the number of optical branch ports of the optical switch.

In addition, through the Ethernet communication device 509 provided in the optical fiber measuring device 500 transmits the measurement results for the corresponding line through the optical fiber path.

In addition to the Ethernet communication device, a method using an appropriate electric communication device such as USB or serial method is also possible.

The optical switch 502 for switching the monitoring light of the OTDR 501 into a plurality of optical lines, and the optical filters 503 and 504 for combining the operating light and the monitoring light, have an optical path measuring apparatus 500 for minimizing optical loss. It is equipped with built-in) and it is natural that it can be separated by a separate independent device.

3 is a configuration diagram of a ring-type optical communication network 300 as another example of an optical communication network to which the distributed control optical fiber monitoring technology may be applied, and the ring-type optical network starts with a central office terminal (COT), which is a central terminal device 301. As a terminal, a plurality of remote terminals (RT) which are a plurality of remote terminal devices 302, 303,.

FIG. 4 is a configuration diagram illustrating an example of a distributed control optical path monitoring method to which the technology of the present invention is applied for monitoring the optical path of the ring optical network of FIG. 3.

In FIG. 4, the monitoring section A of the optical path measuring apparatus 700 among the plurality of optical path measuring apparatuses distributed in the ring optical network is as follows.

The optical path measuring device 700 has an internal structure of the distributed control optical path measuring device 700 shown in FIG. 7, and the distributed control optical path measuring device 700 which can be used in the ring optical network is operated by a microprocessor. And an optical switch 702 for accommodating the OTDR 701 and a plurality of optical paths, and selecting an optical path to be measured and switched under the control of a microprocessor.

As an example of a 1 × 2 optical switch having two switching lines, the two outputs 703 and 704 of the optical switch 702 and the east and west outputs of the remote terminal are connected to the optical filters 413 and 414, respectively. The operating light and the monitoring light are combined.

In the west direction, the optical filter 413 combines the monitoring light from the optical path measuring device 700 and the operating light from the remote terminal device 402 to advance the optical path, and then inside or near the central terminal device 401. The light beam monitoring section is completed up to the monitoring light blocking filter 424 provided.

In the east direction, the monitoring light from the optical path measuring device 700 and the operating light from the remote terminal device 402 are combined in the optical filter 414 to advance the optical path, and then inside or in proximity of the remote terminal device 403. After the monitoring light and the operating light are separated from the installed monitoring light bypass filter 415, the operating light is applied to the remote terminal device 403 to perform a communication operation, and the monitoring light bypasses the remote terminal device 403. In the supervisory light bypass filter 416, the light beam is further recombined with the operating light from the remote terminal device 403, and the optical path is monitored up to the supervision light blocking filter 425 installed in or near the remote terminal device 404. The section is complete.

Optical filters 413 and 414 may be provided inside the optical path measuring device as shown in the optical path measuring device 500 of FIG. 5 in order to ease the operation and reduce the optical loss of the optical connector.

Looking at the monitoring section (B) by the optical path measuring device 800 of the plurality of optical path measuring devices distributed in the ring-shaped optical network in Figure 4 as follows.

The optical path measuring device 800 has an internal structure of the distributed control optical path measuring device 800 shown in FIG. 8, and performs the optical path monitoring only in the West direction to accommodate a plurality of optical paths for sequential shift monitoring. The optical switch 702 does not need to be provided.

The monitoring light from the OTDR 801 operated by the microprocessor and the operating light from the remote terminal device 406 are connected to the optical filter 419 to advance the optical path in the west direction after the operating light and the monitoring light are combined. After the monitoring light and the operating light is separated from the monitoring light bypass filter 418 installed in or near the remote terminal device 405, the operating light is applied to the remote terminal device 405 to perform a communication operation and monitoring. The light bypasses the remote terminal device 405 and recombines with the operating light coming from the remote terminal device 403 in the monitoring light bypass filter 417 to advance the optical path in the west direction, and then inside the remote terminal device 404. Alternatively, the light beam monitoring section is completed by advancing to the monitoring light blocking filter 426 installed in close proximity.

In order to ease the operation and reduce the optical loss of the optical connector, the optical filter 419 may be provided inside the optical path measuring device as in the optical path measuring device 600 of FIG. 6.

The optical path measuring apparatus 600 includes an OTDR 601 and an optical filter 602 to connect the output of the ODTR 601 to the monitoring light input port of the optical filter 602, and then removes the operating light from the optical transmission equipment. When connected to one port 604, the monitoring light from the OTDR 601 is combined by the optical filter 602 and output to the second port 605.

In addition, through the Ethernet communication device 603 provided in the optical fiber measuring device 600 transmits the measurement result for the corresponding line through the optical fiber path.

In addition to the Ethernet communication device, it is also possible to use an electric communication device such as a USB or serial method.

Looking at the monitoring section (C) by the optical path measuring device 800 of the plurality of optical path measuring devices distributed in the ring-shaped optical network in Figure 4 as follows.

Since the optical path measuring apparatus 800 has the internal structure as shown in FIG. 8 and performs the optical path monitoring only in the West direction, it is necessary to include an optical switch 702 for accommodating a plurality of optical paths and sequentially monitoring the optical path. none.

The monitoring light from the OTDR 801 operated by the microprocessor and the operating light from the remote terminal device 407 are connected to the optical filter 420 so that the operating light and the monitoring light are combined, and then the light beam travels in the west direction. After that, the process proceeds to the monitoring light blocking filter 427 installed in or near the remote terminal device 406, thereby completing the light path monitoring section.

Referring to FIG. 4, the optical path monitoring section D by the optical path measuring apparatus 700 among the plurality of optical path measuring apparatuses distributed in the ring optical network is as follows.

The optical path measuring device 700 has an internal structure as shown in FIG. 7, and the two outputs 703 and 704 of the optical switch 702 and the two east and west outputs of the remote terminal device are optical filters 421 and 422. ) And the operating light and the monitoring light are combined. In the West direction, the optical filter 421 combines the monitoring light from the optical path measuring device 412 and the operating light from the remote terminal device 408 to advance the optical path, and then inside or near the remote terminal device 407. The light beam monitoring section is completed up to the installed monitoring light blocking filter 428.

In the east direction, the monitoring light from the optical path measuring device 408 and the operating light from the remote terminal device 408 are combined in the optical filter 422 to advance the optical path, and then inside or near the central terminal device 401. The light beam monitoring section is completed up to the installed monitoring light blocking filter 423.

100; Tree fluorescent network
300; Ring fluorescent network
500,600,700,800; Optical measuring device

Claims (4)

The line terminal device (OLT) and the input of the 1 × N optical splitter are connected by optical paths, and the output of the optical splitter is composed of N branch optical paths. An optical terminal device (ONU or ONT) is connected to the optical communication terminal at the end of each branch optical path. A passive optical network;
It is equipped with the OTDR type optical path measuring device in the form independent of each optical terminal device or close to each optical terminal device and emits monitoring light from the optical terminal device toward the upward line terminal device. Measuring abnormal positions of the back;
The measurement result is transmitted to an electrical communication line connected to the optical termination device, and the optical termination device transmits the received measurement result to the line terminal device through the optical line, and the line terminal device transmits the measurement result received from the optical termination device to the Ethernet switch. A distributed control optical fiber monitoring method, characterized in that measurement of individual optical paths for a plurality of optical beams branched by an optical splitter is made by transmitting to a connected optical fiber monitoring server. A ring type optical communication network in which a plurality of remote terminal devices are connected in a closed curve form by an optical path with a central terminal device as a starting point and an end point;
EAST after the OTDR-type optical fiber measuring device is provided in the form of an independent form at or near the central terminal device, or OTDR-type optical fiber measuring device is provided in the form of an ETDR type at the inside or proximate position of each remote terminal device. Firing the monitoring light signal of the optical path measuring device in the direction or WEST direction to measure an abnormal position such as disconnection, bending, or the like with respect to the optical path in one or two directions connected to the adjacent remote terminal device;
The measurement result is transmitted to the remote terminal device through the electric communication line, and the remote terminal device transmits the measurement result of the received optical fiber measuring device to the central terminal device through the optical path, and the central terminal device is connected to the Ethernet switch. By transmitting to the optical path monitoring server, the optical path measurement results of the partial sections collected from the respective terminal devices are integrated to determine whether there is an abnormality and the position of the entire optical path section constituting the ring optical network. Controlled Beam Monitoring Method. An optical switch controlled by the OTDR and a microprocessor to transfer the monitoring light signal of the OTDR into a plurality of optical paths to measure disconnection and bending positions of the optical paths constituting the optical network;
An optical filter for combining the operating light signal and the monitoring light signal;
A distributed control optical path measurement apparatus, comprising: an electrical communication means for transmitting an OTDR measurement result to an external device. The method of claim 3, wherein
And said optical network is a passive optical network or a ring optical network.

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