JPS585045A - Optical communication device - Google Patents

Abstract

PURPOSE:To easily take a countermeasure to a fault by looping one central device and plural remote devices through one optical fibver cable, and then performing communication. CONSTITUTION:One central device 11 and remove devices 12-14 are looped by one optical fiber cable 20. The central device 11 is equipped with an optical transmitting circuit 21 generates a light signal and an optical branching filter 23 which sends out the light signal through the optical fiber cable 20 in a counter- clockwise direction A and a clockwise diretion B. The remote devices 12-14 are equipped with an optical branchig filter 24 which receives the light signal in either direction of A and B, an optical swtich 25 which selects on signal in the direction A or B, and an optical receiving circuit 26. Therefore, even if a fault occurs at a point 18 between the remove devices 12 and 13, the light signal in the arrival direction is received by changing over the optical switch 25.

Description

[Detailed description of the invention] The present invention relates to a communication device using optical fiber.

4IK, an optical communication device that copes with communication failures that occur in a loop-shaped optical transmission line.

Conventionally, in a loop-shaped optical transmission line, as a countermeasure against communication failure due to disconnection of the optical fiber cable, an optical fiber is installed between the solid device 11 and the remote devices 12, 13, and 14, as shown in FIG. The cables 16 and 17 were laid in duplicate, with the optical fiber cable 164 being used as the active cable and the optical fiber cable 17 being used as a backup in case of a failure. Figures 1) and 1) show the results when only one optical fiber cable is cut and when both optical fiber cables are cut, respectively, in the device shown in Figure 1). Show troubleshooting measures. In other words, in FIG. 1), if the active optical fiber cable 16 is disconnected at the point 18 between the remote devices g112 and 13, the backup optical fiber cable 16 is disconnected from the active optical fiber cable 16. Switching to Aipa Cable 17. In Figure 1 (e), if both the working optical fiber cable 16 and the backup optical fiber cable 17 are cut at the point 18 between the remote devices 12 and 13, the working optical fiber cable 16 and the backup optical fiber cable 17 are cut. In front of the fiber cable 16, one of the standby optical fiber cables 17 serves as the outgoing route, and the other serves as the returning route.

However, in the above-mentioned conventional example, n solid devices and n
This can be an effective countermeasure for communication between remote devices, but
Communication between one solid device and n remote devices requires two optical fibers, which is economically undesirable.

The present invention improves this point, and is an economical optical communication device in which a solid device on one side and n remote devices communicate through one loop-shaped optical transmission path, and which can cope with cable failures. The purpose is to provide

The present invention connects one solid device and n remote devices.
In an optical communication device that performs communication by connecting a single optical fiber cable in the form of a loop, one optical branching device is installed in the solid device to simultaneously send optical signals in both directions of the loop, and to send optical signals to each remote device. is equipped with one optical splitter and one optical switch, and the optical splitter separates the optical signals from the two directions on the loop.
It is characterized in that one of these two signals is selected and received by an optical switch.

Next, a detailed explanation will be given with reference to the drawings.

FIG. 2 is a block diagram of an optical communication device according to an embodiment of the present invention. Second
Figure (IL) and Figure 2 (b) represent the state of the optical loop during normal times and during failures, respectively. In FIG. 2 □ -) and Cb), the solid device 11 and the remote device 12
．． 13 and 14 are connected in a loop by an optical transmission line 20. This optical transmission line 20 is composed of one optical fiber cable.

As shown in FIG.
It is equipped with an optical splitter 23 that outputs light in the counterclockwise input direction and the clockwise direction B. Also remote devices 12.13, and 14
As shown in Figure 5 (b) K, one optical transmission line 200mB has an optical branch 1i 24 that can receive optical signals from either direction, and this 200mB optical branch 1i 24 which can receive optical signals coming from both directions. An optical switch 25 that selects one of the optical signals based on the control signal C, and an optical receiving circuit 26 that receives the selected optical signal are provided.

In this example, it is assumed that cane remote devices 12 and 13 receive an optical signal in the left direction incoming direction, and remote device 14 receives an optical signal in the B direction of the right direction (JIJ).

With this configuration, if a fault occurs at point 18 between remote devices 12 and 13 as shown in Figure 2, then remote devices 12 and 14 will function normally as before. Although the optical signal can be received, the remote device 13 cannot receive the optical signal in the counterclockwise incoming direction.

Then, the optical switch 25 of the remote device 13 is switched from receiving the counterclockwise input optical signal to receiving the clockwise B direction optical signal. As a result, the optical signal coming from the optical transmission line 200B direction is transferred to the optical splitter 24K and then to the optical switch 251).
The optical signal arriving at this point is selected by the control signal 0 and is received by the optical receiving circuit 26 through the point d.

In the above embodiment, an example is shown in which there are five remote devices, but the same implementation is possible even if there are four or more remote devices.

As explained above, according to the present invention, it is possible to economically prevent failures in an optical communication device that performs communication by connecting one solid device and n remote devices in a loop with one optical fiber cable. There are excellent effects that can be achieved by implementing this method.

[Brief explanation of the drawing]

Figure 1 is a configuration diagram of a conventional optical communication installation. FIG. 2 is a configuration diagram of an optical communication device according to an embodiment of the present invention. Figure S is also a detailed configuration diagram of the main parts. 11--solid device, 12.13.14-remote device, 16
... Working optical fiber cable, 17-... Backup optical fiber cable, 18... Fault occurrence point, 2G -...
Optical transmission line, 21... Optical transmitting circuit, 23.24... Optical branching device, 25-- Optical switch, 26... Optical receiving circuit. Patent Applicant: NEC Corporation-7 Agent: Patent Attorney Attorney: `` (a) (b) (Q) (b) 3rd W!J

Claims (1)

[Claims] (1) In an optical communication device in which one solid device and n remote devices communicate by being connected to form a loop through one optical fiber cable, an optical signal is transmitted to the solid device as described above. an optical splitter that simultaneously sends out signals in both directions of the loop, and that allows each of the remote devices to receive any optical signal coming from both directions of the loop, and an optical signal introduced into the optical splitter; An optical communication device comprising: an optical switch that selects one of the optical signals.