JPH0437330A - Optical branching device - Google Patents

Abstract

PURPOSE:To extend a distance between the host device and a repeater by providing an optical amplifier amplifying or interrupting an optical signal branched and attenuated by an optical coupler. CONSTITUTION:An optical signal inputted from a terminal station A is distributed into a photoelectric conversion circuit 5 and a 2nd optical coupler 2 by a 1st optical coupler 1. The optical coupler 2 branches the optical signal into two, they are respectively given to two optical amplifiers 3, 3a. A photoelectric conversion circuit 5 converts the optical signal into an electric signal, which is sent to a control circuit 6. The control circuit 6 controls the gain of the two optical amplifiers 3, 3a in a way of amplification or attenuation with an instruction signal from a terminal station. The optical amplifiers 3, 3a in the active state amplify the optical signal and output the result. Since the optical amplifiers 3, 3a in the inactivating state attenuate the optical signal and output the result, in the case of transmission of the optical signal of the terminal station A to a terminal station B, the optical amplifier 3 is set active and the optical amplifier 3a is set inactive. In the case of transmission of the optical signal to a terminal station C, the setting of the optical amplifiers 3, 3a is opposite to each other in comparison with the setting above.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an optical branching device, and more particularly to an optical branching device having an optical transmission path switching function.

[Conventional technology]

As shown in FIG. 3, in the conventional optical branching device, an optical signal input from the terminal A side is branched and outputted by a first optical coupler 1a to a photoelectric conversion circuit 5a and a second optical coupler 2a. The second optical coupler 2a branches the optical signal into two and outputs the optical shutter 4.
is output to the optical shutter 4a. The photoelectric conversion circuit 5a converts the optical signal into an electrical signal and sends it to the control circuit 6a. The control circuit 6a opens and closes the optical shutter 4 and the optical shutter 4a according to command signals from the terminal station, and switches the optical transmission path.

[Problem to be solved by the invention]

This conventional optical branching device consists of an optical coupler that branches optical signals and an optical shutter that opens and closes optical signals.
This results in optical signal loss in the repeater used. Therefore, the distance between the device and the repeater cannot be increased, which is uneconomical.

[Means to solve the problem]

The optical branching device of the present invention includes: a first optical coupler that branches and outputs an input optical signal into first and second optical signals;
a second optical coupler for branching and outputting an optical signal into a plurality of optical signals; a photoelectric conversion circuit for converting the input second optical signal into an electrical signal and outputting the same; It has a control circuit that outputs a control signal, and a plurality of optical amplifiers that control the gain of the optical signal from the second optical coupler according to the control signal and output it.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram of one embodiment of the present invention.

This embodiment includes a first optical coupler 1 that branches and outputs an optical signal input from a terminal station A into first and second optical signals, and a first optical signal input from the first optical coupler 1 that outputs a plurality of optical signals. A second optical coupler 2 that branches and outputs an optical signal, a photoelectric conversion circuit 5 that converts the second optical signal input from the first optical coupler 1 into an electrical signal and outputs it, and a command included in the input electrical signal. It is configured to include a control circuit 6 that outputs a control signal according to the signal, and a plurality of optical amplifiers 3, 3a that control the gain of the optical signal from the second optical coupler 2 according to the control signal and output it.

Next, the operation will be described. An optical signal input from the terminal A side is distributed by the first optical coupler 1 to the photoelectric conversion circuit 5 and the second optical coupler 2. The second optical coupler 2 branches the optical signal into two and distributes them to two optical amplifiers 3.3a, respectively. The photoelectric conversion circuit 5 converts the optical signal into an electrical signal and sends it to the control circuit 6.The control circuit 6 amplifies (ON) or attenuates (OFF) the gains of the two optical amplifiers 3 and 3a according to a command signal from the terminal station. > The optical amplifiers 3 and 3a in the ON state amplify the optical signal and output it.The optical amplifiers 3 and 3a in the OFF state attenuate the optical signal and output it (the amount of attenuation is large, (Actually, there is almost no output.) Therefore, when sending the optical signal from terminal A to terminal B, the optical amplifier 3
is turned on, and the optical amplifier 3a is turned off. When sending to terminal station C, the opposite operation is performed.

FIG. 2 is a block diagram for explaining the operation of this embodiment. Table 1 shows the transmission line switching logic.

0, Al to O, A6: Optical amplifier Table 1 In this way, if one relay span is Lkm in the conventional example shown in FIG. While m is the permissible transmission distance of the optical signal, in this embodiment it can be set to Lkm as shown in FIG. 4(b).

〔Effect of the invention〕

As explained above, the present invention has an optical amplifier that amplifies or blocks an optical signal that has been branched by an optical coupler and is attenuated, thereby making it possible to increase the distance between the present device and the repeater, thereby reducing the cost of the repeater system. This has the effect of being able to reduce costs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, FIG. 2 is a block diagram for explaining this embodiment, FIG. 3 is a block diagram of an example of a conventional optical branching device, and FIG. 4 is a block diagram of an embodiment of the present invention. FIG. 3 is a configuration diagram for explaining the difference between the example and the conventional one. 1... First optical coupler (CPLL), 2... Second optical coupler (CPL2>, 3... Optical amplifier (OAMP>),
4... Optical shutter (ST), 5... Photoelectric conversion circuit (
○/E)-6=control circuit (CONT).

Claims (1)

[Claims] The first branch outputs the input optical signal into first and second optical signals.
a second optical coupler that branches and outputs the input first optical signal into a plurality of optical signals; and a photoelectric conversion circuit that converts the input second optical signal into an electrical signal and outputs the electrical signal. A control circuit that outputs a control signal according to a command signal included in the input electric signal, and a plurality of optical amplifiers that control the gain of the optical signal from the second optical coupler according to the control signal and output it. Characteristic optical branching device.