Patent ID: 8406635

Claim:
An optical communication system for transmitting an optical signal via an optical transmission line, comprising: an optical signal generator configured to generate an optical signal that transmits a first data signal and a second data signal, in a transmitter; an optical front-end configured to generate a digital signal that represents the optical signal, in a receiver; a detector configured to detect a state of the optical signal by using the digital signal, and output state information that represents the state of the optical signal, in the receiver; a state controller configured to control the digital signal on the basis of the state information in order to recover the first data signal, in the receiver; and a data recovery configured to recover the second data signal on the basis of the state information, in the receiver, wherein the optical signal generator modulates a carrier frequency of the optical signal in accordance with the second data signal, and the data recovery recovers the second data signal by determining an amount of a fluctuation in the carrier frequency.