Patent ID: 6201632
Filing Date: 2001-03-13
Classification: H04B

Abstract:
An optical demodulation system for demodulating an optical carrier signal modulated by a transmitted RF signal, said demodulation system comprising:an optical splitter responsive to the optical carrier signal, said splitter splitting the optical signal into a first split modulated optical signal and a second split modulated optical signal;a coarse optical demodulator responsive to the first split signal, said coarse demodulator demodulating the first split signal and generating a coarse RF signal, said coarse RF signal including the transmitted RF signal and the additive inverse of an error RF signal;a modulator responsive to the second split signal and an additive inverse of the coarse RF signal, said modulator modulating the second split signal with the inverted coarse RF signal so that the transmitted RF signals in the second split signal and the coarse RF signal cancel each other, said modulator generating a modulated error optical signal modulated with the error RF signal;a fine optical demodulator responsive to the error optical signal, said fine demodulator demodulating the error optical signal and generating the error RF signal; anda combiner responsive to the coarse RF signal from the coarse demodulator and the error RF signal from the fine demodulator, said combiner generating a demodulated RF signal.