Amplifier circuit, an optical communication system and a method of controlling amplification

摘要

The invention concerns an amplifier circuit for receiving an optical signal. The circuit comprises a light sensitive member (301) which delivers an electric signal in response to an optical signal. Furthermore, the amplifier circuit comprises an amplifier unit (302) with a first input (304) which receives an electric signal from the light sensitive member (301). The amplifier unit (302) is of the kind which does not have any special input intended for controlling the amplification. A filter unit (310) prevents a possible direct current from the light sensitive member (301) from reaching the first input (304). A control unit (314) is connected to the first input (304) for controlling the amplification of the circuit. The invention also concerns an optical communication system comprising an amplifier circuit of the above-described kind. The invention also concerns a method of controlling the amplification in an optical input stage.