Coherent subcarrier multiplexed optical communication system

An optical communication system comprising:

• transmitter means including means for generating an optical carrier and means for modulating the optical carrier with a composite modulation signal comprising a plurality of modulated microwave subcarriers to provide an optical signal;
• and
• receiver means remotely located from said transmitter means and means for coupling said optical signal from said transmitter means to said receiver means, said receiver means including
• local oscillator means for generating a local light beam, said local oscillator means being tunable over a prescribed frequency range,
• detector means responsive to the received optical signal and said local light beam for providing a detected signal at an intermediate frequency which carries said composite modulation signal, and
• microwave receiver means responsive to the composite modulation signal from said detector means for demodulating at least one of said microwave subcarriers from said composite modulation signal, said microwave receiver means comprising a microwave local oscillator for producing a selectively variable microwave local oscillator frequency, a mixer responsive to said microwave local oscillator frequency and to said detected signal for providing a second intermediate frequency, and a microwave receiver for receiving said second intermediate frequency, said local oscillator means and said microwave local oscillator together permitting selection of a desired microwave subcarrier.