JPH04121715A - Variable amplification factor type optical signal amplifier - Google Patents

Abstract

PURPOSE:To obtain a light output corresponding to an optical reception level by controlling the output level of a semiconductor laser for excitation according to whether or not the input level of a received light signal is large or small. CONSTITUTION:The light signal (wavelength lambda1+wavelength lambda2) from a multiplexer 1 for wavelength multiplexing is demultiplexed by a demultiplexer 6 for wavelength demultiplexing into a light signal with wavelength lambda1, which is monitored by a reception level monitor 7. The monitor 7 monitors the light signal from the demultiplexer 6 and sends out reception level information on an electric signal to a semiconductor laser light emission control circuit 8. The circuit 8 varies the output level of the light signal according to the reception level information to control the optical output of semiconductor lasers 2 and 3 for excitation. The amplification factor for the light signal can be varied according to whether the reception level is large or small.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a direct amplification method for optical signals, and in particular to a variable amplification optical signal amplifier that varies the optical amplification depending on the level of a received optical signal. It is related to.

[Conventional technology]

In conventional optical signal direct amplification methods, the output of the pumping light source was constant regardless of the level of the received optical signal, and the amplification was determined by the optical output of the pumping light source. .

[Problems to be Solved by the Invention] In the conventional optical signal direct amplification method, the output of the excitation light source was constant regardless of the level of the received optical signal. For this reason, the optical output of the excitation light source is increased as much as possible to obtain a higher degree of amplification of the optical signal. However, when considering actual implementation in an optical communication system, it is expected that the necessary amplification degree of the optical signal will change depending on the magnitude of the optical reception level due to the difference in the relay interval, and it is necessary to adjust the amplification degree of the optical signal. There are drawbacks that make it necessary.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate such drawbacks and provide a variable amplification optical signal amplifier whose amplification degree can be variably controlled depending on the level of an optical signal.

[Means to solve the problem]

The variable amplification optical signal amplifier of the present invention controls the output level of the pumping semiconductor laser and controls the amplification depending on the input level of the received optical signal.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

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

This variable amplification optical signal amplifier includes a wavelength multiplexing multiplexer 1
, excitation semiconductor lasers 2 and 3, polarized blood synthesis multiplexer 4, optical fiber amplifier 5, wavelength separation duplexer 6, reception level monitor circuit 7, and semiconductor laser emission control circuit 8. It is equipped with

The excitation semiconductor lasers 2 and 3 send out optical signals (wavelength λ2) to the polarized blood synthesis type trapezoid device 4.

The polarized blood synthesis type multiplexer 4 superimposes the optical signals from the excitation semiconductor lasers 2.3 by a method of combining the polarization planes, and outputs the optical power for two semiconductor lasers to the wavelength multiplexing multiplexer 1. Send to.

A wavelength multiplexing multiplexer 1 multiplexes a weak optical signal (wavelength λ,) propagating through an optical transmission line and an optical signal (wavelength λ2) from the polarization multiplexing demultiplexer 4 to generate a multiplexed optical signal. (wavelength λ1
+wavelength λ2) is sent to the optical fiber amplifier 5 and the wavelength demultiplexer 6.

The optical fiber amplifier 5 optically amplifies the multiplexed optical signal from the wavelength multiplexing multiplexer 1 and outputs an optical signal of wavelength λ1.

The wavelength demultiplexer 6 separates the optical signal from the wavelength multiplexer 1 (wavelength λ1+wavelength λ−) into an optical signal of wavelength λ, and sends the optical signal to the reception level monitor circuit 7.

The reception level monitor 7 monitors the reception level of the optical signal from the wavelength demultiplexer 6 and sends the reception level information of the electric signal to the semiconductor laser emission control circuit 8.

The semiconductor laser destination control circuit 8 varies the output level of the optical signal according to the reception level information from the reception recorder 7. Then, the light emission output of the excitation semiconductor lasers 2 and 3 is controlled.

Next, the operation of this embodiment will be explained. The optical signal (wavelength C + wavelength λ2) from the wavelength multiplexing multiplexer 1 is separated into an optical signal of wavelength C by the wavelength demultiplexer 6, and monitored by the reception level monitor 7. The reception level monitor 7 monitors the optical signal from the wavelength separation demultiplexer 6 and sends reception level information of the electric signal to the semiconductor laser emission control circuit 8. The semiconductor laser emission control circuit 8 changes the output level of the optical signal based on the received level information, and controls the optical output of the excitation semiconductor lasers 2 and 3. Therefore, it is possible to change the amplification degree of the optical signal depending on the magnitude of the reception level.

〔Effect of the invention〕

As explained above, the present invention can control the amplification degree of the optical amplifier depending on the input level of the received optical signal.
Even in an actual optical communication system, there is an effect that an optical output corresponding to the optical reception level can be obtained. Further, it has the effect of reducing power consumption and extending the life of the excitation semiconductor laser.

[Brief explanation of the drawing]

FIG. 1 is a circuit block diagram showing one embodiment of the present invention. 1...Wavelength multiplexing multiplexer 2.3...Semiconductor laser for excitation 4...Polarized blood synthesis multiplexer 5...Optical fiber amplifier 6...・Wavelength separation demultiplexer・Reception level monitor circuit・Semiconductor laser emission control circuit

Claims (1)

[Claims] (1) A variable amplification optical signal amplifier that controls the output level of a pumping semiconductor laser and controls the amplification degree according to the input level of a received optical signal.