Patent ID: 8165476

Claim:
An optical phase locked loop comprising: an optical coupler for receiving an input optical signal and a reproduced optical signal and generating a first optical beat signal from the input optical signal and the reproduced optical signal; a first photoelectric transducer for converting the first optical beat signal to a first converted electrical signal; a first loop filter for converting the first converted electrical signal output by the first photoelectric transducer to a first control signal having a voltage level representing a time-averaged value of the first converted electrical signal; a first voltage controlled oscillator for receiving the first control signal and generating a first radio-frequency signal having a frequency that varies as a function of the voltage level of the first control signal; a local light source for generating a reference optical signal; and a single sideband modulator for using the first radio-frequency signal to perform intensity modulation of the reference optical signal to obtain a plurality of sideband signals, combining the plurality of sideband signals into a single sideband signal including all energy of the plurality of sideband signals, and outputting the single sideband signal as the reproduced optical signal.