JPH03296334A - Optical communication system - Google Patents

Abstract

PURPOSE:To specify a fault location in an optical system quickly with high accuracy by arranging a single or plural optical loopback parts in an optical line. CONSTITUTION:Optical communication terminal equipments 10, 11 are interconnected by optical lines 12, 13 and an optical loopback parts 14 is arranged in plural locations in both the optical lines 12, 13. When a fault takes place in the optical system, the transmission line of a communication signal is selected to each said standby optical line and standby optical parts or the like. In parallel with the changeover of the transmission line, each optical loopback parts 14 is sequentially selected to loop back the communication signal, then a fault location, that is, a fault position is identified.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an optical communication system in which an optical loopback component is arranged within an optical line.

(Prior Art) For example, the system shown in FIG. 8 is known as an optical communication system that transmits optical signals through an optical fiber. This optical communication system is arranged at an optical relay point or the like, and includes an optical communication terminal 1 having an optical transmitter 1a and an optical receiver 1b, and an optical transmitter 2a and an optical receiver 2b configured in the same manner. The communication terminal 2 is optically connected to the communication terminal 2 using a plurality of optical fibers 3.

In this optical communication system, if some kind of communication failure occurs, first, the optical communication terminal 1. 2, optical communication terminal 1.2 is used to determine whether there is a failure in the electrical circuit system.
A loopback operation is performed in the second electrical circuit system. As a result, the transmitting circuit of the optical communication terminal 1 and the receiving circuit of the optical communication terminal 2 or the receiving circuit of the optical communication terminal and the electric circuit system of the transmitting circuit of the optical communication terminal 2 are electrically connected directly, and the optical communication terminal 1,
Determine whether there is an electrical failure between the two.

As a result, if it is determined that there is no failure in the electric circuit system between the optical communication terminals 1 and 2, the failure occurs in the optical system, and a search for the failure point is executed.

To search for such a fault point, OTDR (optic) is usually used to measure the distance to the fault point using backscattering caused by Rayleigh scattering of light incident on the optical fiber.
altime domain reflectomet
er) is used.

(Problem to be solved by the invention) However, in order to analyze the data obtained from 0TDR, 0T
Even excluding the several tens of minutes required for DR setup and warm-up, it takes several tens of seconds to several minutes. Furthermore, the optical system consists of the following: light source at the transmitting station - optical wiring within the optical communication terminal - optical communication terminal rack/optical line termination interframe wiring - optical line outside the station - interframe wiring - optical wiring within the terminal - optical receiver at the receiving station. Yes, and the distance is several -. On the other hand, the resolution of the distance measurement of 0TDR is only several tens of meters to several hundreds of milliliters, which makes it impossible to specifically identify the failure point and is not necessarily satisfactory.

The present invention has been made in view of the above points, and an object of the present invention is to provide an optical communication system that can quickly and accurately identify a failure point in an optical system.

(Means for Solving the Problems) In order to achieve the above object, in the optical communication system of the present invention, one or more optical loopback components are arranged within the optical path.

Preferably, the optical loopback component is an optical switch that switches the optical signal between a through state and a return state, or an optical multiplexer/demultiplexer (hereinafter simply referred to as "optical multiplexer/demultiplexer J") that passes the communication signal and returns the test signal. do.

Here, the optical multiplexer/demultiplexer not only multiplexes and demultiplexes light, but also
Including those with a filtering function that selectively transmits or cuts light of a specific wavelength.

(Function) The optical loopback component disposed within the optical path loops back the light by switching the optical path or branching and combining the light. Therefore, simply by looping back the signal light using an optical loopback component whose position is known in advance, the point of failure can be quickly and accurately identified.

(Example) Hereinafter, a first example of the present invention will be described in detail based on FIGS. 1 to 4.

FIG. 1 is a basic configuration diagram showing an optical communication system of the present invention, in which optical communication terminals 10.11 are optically connected by optical lines 12.13, and both optical lines 12.11 are optically connected. Optical loopback components 1 are installed at multiple locations within 13.
4 is placed.

Here, the optical communication system is equipped with a backup optical line, a backup optical component, etc. (not shown), which are switched when a failure occurs, as a countermeasure against a failure in the optical system.

The optical communication terminal 10.11 is equipped with light sources 10a, 11a and light receivers 10b, llb, and has an optical path 12 as shown in the figure.
．． 13, they are optically connected to each other so that communication signals can be transmitted and received.

The optical line 12.13 is composed of a plurality of optical fibers,
The transmission directions of communication signals are different.

The optical loopback component 14 is an optical switch consisting of a fixed connector 15 and a movable connector 16, as shown in FIG. It is optically connected to optical lines 12 and 13 of. Furthermore, the movable connector 16 is provided with a zero-shaped fiber coil 16b.

As described above, the optical communication system of the present invention includes optical lines 12.
A plurality of optical loopback components 14 are arranged at 13 .

In this optical communication system, when a failure occurs in the optical system, the transmission path of the communication signal is switched to each of the above-mentioned spare optical lines and spare optical components. When the movable connector 16 of the optical loopback component 14 is switched as shown in FIG. 3 in parallel with such switching of the transmission path, the communication signal can be looped back. Therefore, by sequentially switching each optical loopback component 14 and looping back the communication signal, it is possible to identify the faulty section, that is, the faulty position.

Here, in this optical communication system, switching to the above-mentioned backup optical line, etc. due to the occurrence of a failure must be performed quickly, but since the communication signal transmission path is switched to the backup optical line, etc., there is no problem with optical communication. There is no need to rush to identify the location of the failure.

In addition, in this optical communication system, the optical line 12.1
3, in addition to the communication signal (wavelength λoP), the test signal (wavelength λoP)
When introducing T), as an optical loopback component,
The optical multiplexer/demultiplexers 17 and 18 shown in FIG.
13, and an optical line 19 optically connects the optical multiplexer/demultiplexer 17 and 18. In this case, the optical multiplexer/demultiplexer 17 functions as an optical multiplexer and the optical multiplexer/demultiplexer 19 functions as an optical multiplexer.

Next, a second embodiment of the present invention will be described. FIG. 5 shows an optical communication system related to a two-way communication system such as an integrated service digital network, in which optical line optical multiplexer/demultiplexers 22 and 23 are arranged between optical communication terminals 20 and 21.
．． An optical loopback component 25 is disposed on an optical path 24 that optically connects the optical fibers 23 to 23.

The optical communication terminal 20.21 includes light sources 20a, 21a and light receivers 20b, 21b, respectively, and as shown in the figure, optical lines 26, 27 and 28 are connected to the optical multiplexer/demultiplexer 22, 23, respectively. It is connected with .29. Here, the light source 20
a emits a signal light having a wavelength λ1, and a light source 21a emits a signal light having a wavelength λ.

The optical multiplexer/demultiplexer 22.23 has wavelengths λ1. It performs multiplexing and demultiplexing of signal light of λ, and is not involved in optical loopback.

As the optical loopback component 25, for example, an optical switch shown in FIG. 6 is used. This optical loopback component 25 is
This is an optical switch consisting of a fixed connector 25a and a movable connector 25b. An optical path 25c is formed inside the fixed connector 25a. Moreover, the movable connector 25b has optical paths 25c parallel to each other! , 25e are formed, and an optical mirror 30 that reflects the signal light propagated through the optical path 25e is formed on the side surface of the movable connector 25b where one optical path 25e opens.

Therefore, in the optical communication system of this embodiment, a signal light of wavelength λ1 is emitted from the light source 20a of the optical communication terminal 20, and a signal light of wavelength λ! is emitted from the light source 21a of the optical communication terminal 21. signal light is transmitted to each other party.

Then, the signal light (wavelength λ1) transmitted from the light source 20a of the optical communication terminal 20 travels through the optical line 26 → optical multiplexer/demultiplexer 22 → optical loopback component 25 → optical multiplexer/demultiplexer 23, and then reaches the optical communication terminal 21 The light is received by the light receiver 21b. In addition, the signal light (wavelength λ2
) is received by the light receiver 20b of the optical communication terminal 20 through a path opposite to this, and bidirectional wavelength division multiplexing communication is performed in this way.

In this optical communication system, when specifying a faulty section, that is, a fault position, that has occurred in the optical system, the movable connector 25b of the optical loopback component 25 is connected to the fixed connector 25a.
move against. As a result, the movable connector 25b
The optical path 25c of the fixed connector 25a, which was connected to the optical path 25d of , is switched to the optical path 25e of the movable connector 25b.

Therefore, the signal light (wavelength λ,) transmitted from the optical communication terminal 2° side through the optical line 24 is reflected by the optical mirror 30 formed in the optical loopback component 25, and follows the same path toward the optical communication terminal 20 side. Go backwards. Similarly, the signal light (wavelength λ) transmitted from the optical communication terminal 21 side through the optical path 24 is reflected by the optical mirror 3o and returns to the optical communication terminal 21 side. This light Due to the loopback of the signal light by the loopback component 25,
It is possible to specify the fault area, that is, the fault location.

Here, an optical multiplexer/demultiplexer 26 shown in FIG. 7 may be used as the optical loopback component. The optical multiplexer/demultiplexer 26 includes a Y-branch type optical path and has three optical ports 26a to 26c, and an optical mirror 31 is formed in the optical port 26c. This optical multiplexer/demultiplexer 26 receives signal light (wavelength λ1.λ) and test light (wavelength λT
), and the signal light (wavelength λ1.λ
t), the test light (wavelength λT) is emitted from the optical port 26c.

(Effects of the Invention) As is clear from the above description, according to the optical communication system of the present invention, one or more optical loopback components are disposed within the optical path, so that failure points in the optical system can be quickly and easily fixed. Can be identified with high accuracy.

[Brief explanation of the drawing]

1 to 4 show a first embodiment of the present invention. FIG. 1 is a basic configuration diagram of an optical communication system, FIG. 2 is a configuration diagram of optical loopback components, and FIG. 3 is a diagram of a basic configuration of an optical communication system. Figure 2 is a configuration diagram showing a state in which the same components as above are switched, Figure 4 is a configuration diagram when the optical loopback component is an optical multiplexer/demultiplexer, and Figures 5 to 7 are a diagram showing a second embodiment of the present invention. 5 is a basic configuration diagram of the optical communication system, FIG. 6 is a configuration diagram of optical loopback components,
FIG. 7 is a configuration diagram when an optical multiplexer/demultiplexer is used as an optical loopback component, and FIG. 8 is a basic configuration diagram of a conventional optical communication system. 12.13... Optical line, 14... Optical loopback component (optical switch), 17.18... Optical multiplexer/demultiplexer (optical loopback component), 24... Optical line, 25... Optical loopback component (optical switch), 26... optical multiplexer/demultiplexer (optical loopback component).

Claims (3)

[Claims] (1) An optical communication system characterized by placing one or more optical loopback components in an optical path. (2) Claim 1, wherein the optical loopback component is an optical switch that switches an optical signal between a through state and a return state.
The optical communication system described. (3) The optical communication system according to claim 1, wherein the optical loopback component is an optical multiplexer/demultiplexer that passes communication signals and returns test signals.