Fiber optic digital transmission system

摘要

A transmission system responsive to an electrical input information signal includes means for modulating the input signal with a microwave subcarrier signal to produce a subcarrier modulated signal. A first interferometric modulator responsive to a source light and to the subcarrier modulated signal produces a first modulated optical signal. A second interferometric modulator cascade coupled to the first modulator and being responsive to the first modulated optical signal and to a microwave local oscillator signal produces a second modulated optical signal. Means coupled between the first and second modulators transmit the first modulated optical signal from the first modulator to the second modulator. Means responsive to the second modulated optical signal produce an output signal.