KR20090124437A - Fixed reflector for OTDR and light path monitoring device using the same - Google Patents

Abstract

The present invention relates to a fixed reflector for OTDR and an optical path monitoring device using the same, and more particularly, a characteristic of a terminal having some reflection characteristics improved by coating to reflect only the monitoring light on one side or both sides of a ferrule connecting an optical fiber. The present invention relates to a fixed reflector for an OTDR capable of reflecting a monitoring light irrespective of a light and an optical path monitoring device using the same.

The present invention relates to a reflector for reflecting surveillance light with an optical time-domain reflectometer (OTDR), which is connected to an optical fiber 20 forming an optical path, and which is adjacent to the core 24 of the optical fiber. It is characterized by a fixed reflector for OTDR, which is formed by forming partial wavelength reflecting coatings 18 and 19 reflecting the monitoring light on one or both sides.

At this time, it is preferable that the ferrule further comprises another ferrule so as to be adjacent to the wavelength reflection coating formed on the ferrule.

Description

Fixed reflector for OTDR and optical path monitoring device using the same {FIXED REFLECTOR FOR OTDR AND SUPERVISORY APPARAUS THEREUSE}

The present invention relates to a fixed reflector for OTDR and an optical path monitoring device using the same, and more particularly, a characteristic of a terminal having some reflection characteristics improved by coating to reflect only the monitoring light on one side or both sides of a ferrule connecting an optical fiber. The present invention relates to a fixed reflector for an OTDR capable of reflecting a monitoring light irrespective of a light and an optical path monitoring device using the same.

In general, an optical power meter or an optical time domain reflectometer (OTDR) is used as a device for monitoring breakage and failure of an optical path.

The optical power meter is a reflectance measuring device using an optical source and an optical fiber reflector. In general, the optical power meter is configured by connecting an optical fiber reflector to an output port of a 50:50 coupler to measure reflectance of various wavelengths.

As the light source, a laser having a variable wavelength can be used to enter one of the input ports of the coupler, and a light meter is connected to the remaining input ports of the coupler to reflect the signal light reflected from the optical fiber reflector. Is detected.

On the other hand, the optical fiber loss measuring system using the OTDR as shown in Figure 4, when the optical power obtained from the light source 31 is incident on the optical fiber 20 to be measured, the backscattered light generated in the optical fiber is proportional to the distance to the reflection point After an hour, return to the entrance.

The OTDR 30 separates the returned light into the directional optical coupler 32, detects the light by the photodetector 33, converts the light into an electrical signal, and then converts the waveform into the oscilloscope 35 through the signal processor 34. Observe and record it through the recorder 36.

At this time, the backscattered light is proportional to the intensity of the optical power proceeding toward the exit end, and the connection loss, breakage point, the length of the optical fiber, etc. can be measured using the backscattered light.

Such optical power meter or OTDR equipment is widely used to measure the failure when the optical fiber failure.

However, in order to monitor the failure or failure as mentioned above, first, it is necessary to find out the value in the steady state, but in recent years, since the reflection characteristics of all parts are greatly improved by products, the OTDR signal is transmitted to the terminal and reflected through the medium. There is a problem in that it is difficult to obtain such a reflection characteristic, although it is necessary to detect a return signal.

In addition, the optical fiber Bragg grating device (Brag grating) is used as a reflector, the product of the optical fiber Bragg grating device is expensive, and the volume is in the form of optical fiber has a problem that is difficult to handle.

The present invention is to solve the above problems, an object of the present invention is to reduce the manufacturing cost, and to reflect the monitoring light to effectively detect the monitoring light, it is convenient to install and handle to greatly improve the efficiency of the product It is to provide a fixed reflector for OTDR and a light path monitoring device using the same.

In other words, a coating process is performed to reflect only the monitoring light on one side or both end surfaces of the ferrule connecting the optical fibers, thereby providing a fixed reflector capable of reflecting the monitoring light regardless of the characteristics of the terminal having some improved reflection characteristics. In addition, it is an object to provide a cheap and efficient fixed reflector for OTDR and a light path monitoring device using the same by arranging ferrules before and after the coating to protect such wavelength reflection coating.

The present invention relates to a reflector for reflecting surveillance light with an optical time-domain reflectometer (OTDR), which is connected to an optical fiber 20 forming an optical path, and which is adjacent to the core 24 of the optical fiber. It is characterized by a fixed reflector for OTDR, which is formed by forming partial wavelength reflecting coatings 18 and 19 reflecting the monitoring light on one or both sides.

At this time, it is preferable that the ferrule further comprises another ferrule so as to be adjacent to the wavelength reflection coating formed on the ferrule.

On the other hand, the present invention is a wavelength division multiplexing passive optical subscriber network (WDM-PON) including an optical fiber termination unit (OLT) as a central base station, an optical communication network unit (ONU) at the subscriber side and a remote node (RN) as a local base station. A subscriber line based optical line monitoring device, further comprising: a monitoring light coupler (43) for coupling the signal light of the optical ray termination device and the monitoring light output from the OTDR (30), The optical path monitoring device comprising the fixed reflector for OTDR of claim 1 or 2, which reflects the monitoring light at an input terminal.

According to the present invention, even in a system equipped with terminals having excellent reflection characteristics, only the monitoring light can be effectively reflected so that failures and failures can be easily monitored.

In addition, it is easy to maintain the monitoring system because it is easy to handle, and has a simple structure and low-cost fixed reflector has the effect that can effectively operate the optical line monitoring device.

Hereinafter, with reference to the accompanying drawings will be described in detail the fixed reflector for OTDR and the optical path monitoring apparatus using the same.

1 is a schematic cross-sectional view of a fixed reflector for OTDR according to an embodiment of the present invention, Figure 2 is a main configuration of a fixed reflector for OTDR according to another embodiment of the present invention, Figure 3a FIG. 3B is a schematic configuration diagram of an optical path monitoring apparatus using a fixed reflector for an OTDR, and FIG. 3B is a schematic configuration diagram of a remote node of FIG. 3A.

In adding the reference numerals to the components of the drawings, the same components are to have the same reference numerals as possible even if displayed on different drawings, and known functions that are determined to unnecessarily obscure the subject matter of the present invention Detailed description of the configuration will be omitted.

The fixed reflector for the OTDR according to the preferred embodiment of the present invention is connected to the optical fiber 20 forming the optical path as shown in FIG. 1, and the ferrule 12 is adjacent to the core 24 of the optical fiber. Some wavelength reflection coatings 18 and 19 are formed on one side or both sides of the surface to reflect the monitoring light of a specific wavelength band.

In this case, the ferrule 12 is protected by the ferrule housing 14 and connected to the optical fiber 20 and the connectors 15 and 16. Reference numeral 22 denotes a coating of the optical fiber, and since the ferrule 12 and the connectors 15 and 16 are well known in the art, detailed description thereof will be omitted.

On the other hand, Figure 2 is a schematic configuration of a fixed reflector for OTDR according to another embodiment of the present invention, it is configured by forming the partial wavelength reflection coating 18 between the two ferrules (12). In other words, it is a configuration for effectively protecting the partial wavelength reflection coating 18.

The partial wavelength reflection coating is a filter coating on the side of the ferrule 12 by the well-known technique to reflect the monitoring light used in the OTDR. In this case, the monitoring light generally uses light having a wavelength of 1310 nm, 1550 nm, and 1625 nm.

In addition, as described above, since the fixed reflector of the present invention can be used as a single component of various types (SC, FC, APC, PC type), it is very easy to use.

3A is a schematic block diagram of a WDM-PON-based subscriber side optical line monitoring device based on a wavelength division multiplexing method, an optical fiber termination unit (OLT) 40 serving as a central base station, and an optical communication network unit at a subscriber side. (ONU: 60, 68) and an optical distribution network (ODN) including a local node remote node (RN: 50).

In the WDM-PON, a plurality of ONUs are connected to the OLT through a plurality of optical links by using a WDM scheme for multiplexing wavelengths by subscriber or service. In OLT, optical signals with different wavelengths are generated, and the optical distribution network of RN located between OLT and ONU is transmitted by routing, multiplexing, and demultiplexing signals using passive optical elements such as arrayed waveguide grating (AWG). By physically connecting OLT and ONU.

Such AWGs are also called Waveguide Grating Routers (WGRs) or Phased Arrays (PHASARs). At this time, the location of the optical distribution network is determined according to the optimal network design considering the environment in which the WDM-PON is to be installed. The location of the optical distribution network may be located at a remote site or in a central office where the OLT is located.

The OLT 40 generates a signal light having a plurality of different wavelengths, multiplexes it, and transmits the signal light to the RN 50. On the contrary, the OLT 40 is transmitted to the RN 50 from several ONUs 60 and 68 to the OLT 40. Receive the signal.

The OLT 40 multiplexes and outputs a plurality of light sources 41 that generate and output signal light having a specific wavelength, such as a laser, and multiplexed signal light of different wavelengths by the plurality of light sources 41, and multiplexes and receives a received signal. It may be provided with an AWG output by demultiplexing for each wavelength.

As illustrated in FIG. 3B, the RN 50 includes an AWG 52 for multiplexing or demultiplexing a signal of the OLT 40, and power of an incident light positioned at an input terminal of the AWG 52. The splitter 54 includes a splitter 54 for distributing and coupling the output signal of the AWG 52 and the output signal of the splitter 54 to output to each output terminal of the AWG 52. 3B illustrates an example of multiplexing AWG, and the splitter 54 and the coupler 56 preferably use WDM.

That is, since the AWG 52 does not pass the OTDR surveillance light, the OTDR surveillance light should be bypassed using the splitter 54 and the coupler 56.

On the other hand, the optical path monitoring device of the present invention further includes a monitoring light coupler 43 for coupling the signal light of the light source 41 and the monitoring light (pulse) from the OTDR 30.

The optical time domain reflectometer (OTDR) 30 inputs an OTDR pulse (surveillance light) having a wavelength different from that of the signal light into the optical fiber, and analyzes the distance distribution of the amount of light reflected and returned from each point in the longitudinal direction of the optical fiber, It is a device for measuring the distance to the connection point, the connection loss, the amount of reflection from the connection point, and the distance to the break point when the optical fiber is broken. The OTDR pulse (monitoring light) is mainly used for a semiconductor laser having a small light intensity and a large light intensity, and a wavelength can be used in a range (1300 nm to 1550 nm) of a single mode optical fiber.

The OTDR (30) is a device that can measure the break point, the distance of the optical cable, etc. by looking at the return time of the reflected light and the amount of Rayleigh scattering, Fresnel reflected light by the difference in the refractive index of the optical fiber by the incident light It is sometimes referred to as an optical echo tester (OET), an optical pulse tester (OPT), or an optical fiber analyzer (OFA), and a microprocessor is embedded in the instrument to enable digital measurement. It is.

The RN 50 splits the multiplexed WDM signal light for each wavelength, distributes power of the monitoring light, and combines the monitoring light distributed to each signal light branched for each wavelength to turn on each of the ONUs 60 and 68 as optical communication network termination devices. To send. Then, the signal light and the monitoring light from each of the ONUs 60 and 68 are transmitted to the OLT 40.

3A and 3B are exemplary embodiments in which the fixed reflector 10 of the present invention is configured, but is not limited thereto.

Referring to the operation of the optical path monitoring device according to the present invention as described above, signal light of different wavelengths from the light source 41 is output together with the monitoring light of the OTDR (30).

The signal light and the monitoring light is combined by the monitoring light coupler 43 and transmitted to the remote node 50 along the optical path.

At this time, the combined monitoring light travels along the optical path, and the signal light is branched by the AWG of the RN 50 for each wavelength and output to the corresponding output port, and the monitoring light is bypassed without passing through the AWG of the RN 50. In other words, the splitter 54 of the RN 50 distributes the WDM signal light of each wavelength through the AWG 52 and the bypassed monitoring light through the coupler 56 to reconnect each subscriber optical path. Therefore, proceed to the corresponding ONU (60, 68).

Surveillance light traveling to each subscriber line is scattered and reflected according to the state of the light path, and proceeds in the opposite direction to the original traveling direction, and is incident to the OTDR 20.

At this time, the OTDR 30 can distinguish the monitoring light that has passed through each subscriber line by the fixed reflector 10 reflecting only a specific monitoring light to the input terminal of each ONU 60, 68.

The OTDR 30 compares the signal analysis waveform and the reference signal analysis waveform of the received monitoring light and analyzes whether there is an abnormality such as how much signal loss occurs in each subscriber's optical path, thereby transmitting the physical characteristics of the optical path of each subscriber. At the same time, it is always monitored.

The embodiments of the present invention described above and illustrated in the drawings should not be construed as limiting the technical spirit of the present invention. The protection scope of the present invention is limited only by the matters described in the claims, and those skilled in the art can change and change the technical idea of the present invention in various forms. Therefore, such improvements and modifications will fall within the protection scope of the present invention if it is obvious to those skilled in the art.

1 is a schematic cross-sectional view of a fixed reflector for OTDR according to an embodiment of the present invention,

2 is a main configuration of a fixed reflector for OTDR according to another embodiment of the present invention,

3A is a schematic configuration diagram of a light beam monitoring apparatus using a fixed reflector for OTDR according to an embodiment of the present invention;

3B is a schematic structural diagram of a remote node of FIG. 3A;

Figure 4 is a conventional optical fiber monitoring apparatus using OTDR.

<Description of Symbols for Main Parts of Drawings>

10: fixed reflector 12: ferrule

14: ferrule housing 15, 16: connector

18, 19: partial wavelength reflection coating 20: optical fiber

22: sheath 24: core

30: Optical time domain reflectometer (OTDR)

31, 41: light source 32: light direction coupler

33: photodetector 34: signal processor

35: oscilloscope 36: recorder

40: Optical Line Termination (OLT) 43: Supervisory Coupler

44: monitoring light 50: RN (Remote Node)

52: Arrayed Waveguide Grating (AWG) 54: Splitter

56: Coupler 60, 68: ONU (Optical Network Unit)

62, 67: Bragg grating fiber

Claims (3)

A reflector that reflects surveillance light with an optical time domain reflectometer (OTDR), To be connected to the optical fiber 20 forming the optical path, The fixed reflector for OTDR, characterized in that the partial wavelength reflection coating (18, 19) reflecting the monitoring light is formed on one side or both sides of the ferrule (12) adjacent to the core (24) of the optical fiber. The method of claim 1, The fixed reflector for OTDR, characterized in that it further comprises another ferrule so as to be adjacent to the partial wavelength reflection coating formed on the ferrule. Subscriber side light based on WDM-PON (WDM-PON) wavelength division multiplexing system which includes an optical fiber termination unit (OLT) as a central base station, an optical communication network unit (ONU) at the subscriber side, and a remote node (RN) as a local base station. Furnace monitoring device, And a monitoring light coupler 43 for coupling the signal light of the optical path terminating device and the monitoring light output from the OTDR 30, And the fixed reflector for OTDR of claim 1 or 2, which reflects the monitoring light at an input of an optical communication network unit at the subscriber side.

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