| 摘要 |
PROBLEM TO BE SOLVED: To provide a receiver capable of accurately demodulating a signal having a deteriorated signal-to-noise ratio. SOLUTION: An optical signal inputted from an optical multiplexer/ demultiplexer 42 is modulated with an electric signal of the oscillation frequency from an oscillator 46 by an optical modulator 43 to perform a multiplication operation, and is converted into an electric signal by a photoelectric conversion element 44. In a loop circuit 47, the oscillation frequency and phase of the oscillator 46 are controlled by using this electric signal, and the oscillation output is phase-synchronized with a sub-carrier signal to obtain a base band signal by the output from an amplifier 45. |
