Staas & Halsey
Optical communication system
 An optical communication system in which light is modulated in sending equipment according to a composed signal obtained by mixing a signal frequency-multiplexed at the microwave level in a coherent SCM optical communication system with an unmodulated signal out of the frequency band of the frequency-multiplexed signal. The resultant modulated light is optical-heterodyne-detected. A demodulating unit demodulates a frequency-multiplexed signal according to an electric signal delayed by a delay unit by the time equal to the time delay in an unmodulated component extracting unit. Only the frequency components of a frequency-multiplexed signal and an unmodulated signal must be received in receiving equipment, without receiving the component in a broad frequency band from the frequency component to the main carrier component of the frequency-multiplexed signal. 
Fujitsu Limited
H
H04J
inventional
Shigeki
Watanabe