Patent ID: 8445832

Claim:
An optical communication device comprising: a pre-amplifier circuit including an input node to which a current signal from a photodiode is inputted and an output node, and amplifying a current signal from the input node, converting an amplified signal into a voltage signal, and outputting a converted signal to the output node; and a first controller circuit controlling the pre-amplifier circuit, the pre-amplifier circuit including: a first level-shift circuit provided on a first path between the input node and the output node, and level-shifting a voltage level of a signal inputted via the input node by an amount in accordance with a first control signal; a first amplifier circuit connected to a subsequent stage of the first level-shift circuit on the first path, and amplifying an output signal of the first level-shift circuit with a negative gain and outputting an amplified signal to the output node; and a feedback resistance provided on a second path connected in parallel to the first path between the input node and the output node, the first controller circuit including a replica circuit having a replica of the first amplifier circuit with an input and an output thereof being electrically connected to each other, the first controller circuit generating the first control signal so that a direct current level of an output signal of the replica circuit is matched with a direct current level of an input signal of the first amplifier circuit.