Patent ID: 7742706

Claim:
A dispersion compensation type optical signal receiving apparatus, comprising: a photoelectric converting device for converting input signal light inputted from a transmission line into an electric signal; an amplifying device for amplifying the electric signal converted by the photoelectric converting device; an electronic dispersion compensation device for electrically compensating dispersion in the transmission line, targeted at a receiving signal that corresponds to the input signal light that is converted into the electric signal and amplified; a signal reproducing device for reproducing clock and data from the receiving signal to which dispersion compensation is performed; a variable optical attenuation device which operates to limit a power of the input signal light inputted to the photoelectric converting device; and an attenuation amount controlling device for activating the variable optical attenuation device when the power of the input signal light is larger than a reference value with which an output amplitude of the amplifying device does not saturate, and controlling an attenuation amount of the variable optical attenuation device based on an output value outputted by a level detecting device in proportion to an output voltage of the amplifying device.