Patent ID: RE39785

Claim:
A transmission system for optically transmitting a frequency-division-multiplexed signal, which is obtained by frequency-division multiplexing a plurality of signals, said transmission system comprising: a transmitting end comprising a multiplexer operable to freqeuncy-division multiplex the plurality of signals to produce the frequency-division multiplexed signal, a FM modulator being operable to convert the frequency-division-multiplexed signal into a frequency-modulated signal through frequency modulation using the frequency-division-multiplexed signal as an original signal to output the frequency-modulated signal as a FM modulated signal, and an optical transmitter operable to convert the FM modulated signal into an optical-intensity-modulated signal whose optical carrier component is suppressed in an optical frequency spectrum through optical modulation using the FM modulated signal as an original signal to send the optical-intensity-modulated signal to a receiving end; and said receiving end comprising an optical receiver operable to receive the optical-intensity-modulated signal from said optical transmitter, and convert the optical-intensity-modulated signal into an electrical signal corresponding to the FM modulated signal through photodetection based on a square-law detection characteristic to the output the electrical signal as a received FM modulated signal, and a FM demodulator operable to demodulate the received FM modulated signal to reproduce the frequency-division-multiplexed signal.