JPH04275530A - Optical amplifier circuit - Google Patents

Abstract

PURPOSE:To stabilize the optical amplification gain to multiwavelength inputs and to prevent the generation of waveform distortions generated by an excessively amplified output, etc. CONSTITUTION:This optical amplifier circuit has a pilot light generating circuit 4 which generates the pilot light of a preset level, a 1st coupler 1 which inserts this pilot light to a light input signal, an optical amplifier 2 which amplifies the light signal delivered from this 1st coupler 1 at the amplification rate determined according to a control voltage, a 2nd coupler 3 which branched the light signal delivered from this optical amplifier to two signals, and using one thereof as an output signal, a filter 5 which extracts the component of the above- mentioned pilot light in the one branched signal of the 2nd coupler 3, a photoelectric converter 6 which converts the above-mentioned pilot light component extracted by this filter 5 to an electric signal and an amplifier 7 which generates the above-mentioned control voltage to be applied to the above-mentioned optical amplifier 2 in response with the electric signal delivered from this photoelectric converter.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical amplification circuit, and more particularly to an optical amplification circuit capable of stabilizing the optical amplification factor.

0002

2. Description of the Related Art Conventional optical amplifier circuits do not have a function to stabilize the optical amplification factor.

0003

[Problems to be Solved by the Invention] When such a conventional optical amplification circuit that does not have the function of stabilizing the optical amplification factor is used to amplify a multi-wavelength signal, it is difficult to avoid the effects of wavelength multiplexing. As a result, the optical amplification factor changes, causing problems such as waveform distortion due to excessive output.

0004

[Means for Solving the Problems] The optical amplification circuit of the present invention includes:
a pilot light generation circuit that emits pilot light at a preset level; a first coupler that inserts the pilot light into an optical input signal; and an optical signal sent out from the first coupler with an amplification factor determined according to a control voltage. an optical amplifier for amplification, a second coupler for splitting an optical signal sent out from the optical amplifier into two and using one as an output signal, and extracting a component of the pilot light in the other branched signal of the second coupler. an opto-electrical converter that converts the pilot light component extracted by the filter into an electrical signal; and an amplifier that generates the control voltage to be applied to the optical amplifier in response to the electrical signal sent from the opto-electric converter. It is equipped with

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention. The optical input signal is an n-wave multiplexed signal of wavelengths λ1 to λn in FIG. A pilot light signal of a constant level with a wavelength λp emitted by a pilot light generation circuit 4 is inserted into this signal by a coupler 1, amplified by an optical amplifier 2, and outputted through a coupler 3.

The optical amplifier 2 may be a semiconductor laser amplifier, an erbium doped fiber (EDP), or the like.
An optical amplifier is used that can variably control the optical amplification factor by applying a DC voltage. From the optical signal split by the coupler 3 to the filter 5
extracts a pilot light component of wavelength λp, converts it into an electrical signal with an opto-electrical converter 6, amplifies the difference between this voltage and a reference voltage with an amplifier 7, and supplies it to the optical amplifier 2 to obtain an optical amplification factor. controlled. Through this control, it is possible to stabilize the level of the pilot optical signal in the optical output signal, thereby stabilizing the optical amplification factor between input and output to a desired value.

[0008]

[Effects of the Invention] As explained above, according to the present invention, by stabilizing the gain of the optical amplifier according to the output level of the pilot light component, the optical amplification gain for multi-wavelength input can be stabilized. Waveform distortion caused by amplified output etc. can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the invention.

FIG. 2 is an optical signal spectrum diagram of an embodiment of the present invention.

[Explanation of symbols]

2 Optical amplifier 1,3 Coupler 4 Pilot light generation circuit 5 Filter 6 Photoelectric converter 7 Amplifier

Claims (3)

[Claims] 1. A pilot light generation circuit that emits pilot light at a preset level, a first coupler that inserts the pilot light into an optical input signal, and a transmitting optical signal of the first coupler according to a control voltage. an optical amplifier that amplifies the optical signal with an amplification factor determined by the optical amplifier; a second coupler that splits the output optical signal of the optical amplifier into two and uses one as an output signal; and the pilot in the other branched signal of the second coupler. a filter that extracts a light component; a photoelectric converter that converts the pilot light component extracted by the filter into an electrical signal; and the control that is applied to the optical amplifier in response to the electrical signal sent from the photoelectric converter. An optical amplification circuit characterized by comprising: an amplifier that generates a voltage. 2. The optical amplification circuit according to claim 1, wherein the optical amplifier is a semiconductor laser amplifier. 3. The optical amplification circuit according to claim 1, wherein the optical amplifier is an erbium-doped fiber.