DOUBLE-STAGE PHASE-DIVERSITY RECEIVER

摘要

PURPOSE:To obtain the advantages of a homodyne system and a heterodyne system simultaneously by multiplying plural electric signals being the result of mixing an electric signal or an optical signal with a local oscillating light with a local oscillation signal, adding the results and demodulating the sum with the heterodyne system. CONSTITUTION:An optical local oscillator 16 is connected to a hybrid circuit 11, optical signal and local synthesis lights which the phase difference of signal light and local oscillation light is 90 deg. are outputted from an output port and given to mixers 141, 142. A local oscillation current whose phase is deviated by 90 deg. from an electric local oscillator 18 is given to the mixer 141, multiplied with the input of a 1st port, and a local oscillating current is given from the local oscillator 18 to a mixer 142 directly and multiplied with the input of a 2nd port. Then the outputs are added by an adder 20 and given to an equalizer 21 and demodulated by a demodulator 22. Thus, the homodyne detection and the heterodyne demodulation are obtained and only the advantages of the homodyne system and the heterodyne system are obtained.