Patent ID: 7720394

Claim:
An optical reception circuit, comprising: a photoelectric converter converting reception light into an electric signal; a pre-amplifier for amplifying the electric signal; a main amplifier amplifying an output of said pre-amplifier; a monitor monitoring the output of said pre-amplifier; and a controller controlling an identification level in said main amplifier based on an output of said monitor; said monitor including: a limiter amplifier amplifying the output of said pre-amplifier; and an average value detector detecting a time average value of an output amplitude of said limiter amplifier, wherein said controller calculates a relationship of the identification level to the time average value of the output amplitude of said limiter amplifier, based on a relationship of a duty of an output waveform of said pre-amplifier to the time average value of the output amplitude of said limiter amplifier and a relationship of a chromatic dispersion amount of the reception light to the duty and a relationship of the identification level to the chromatic dispersion amount, and controls the identification level in said main amplifier based on the result of the calculation.