Staas & Halsey
Polarization diversity optical receiver for coherent optical communication
 A polarized wave diversity optical receiver for coherent optical communication including: an optical local oscillating circuit (7) for oscillating local oscillating light; a mixing circuit (8) for mixing signal light and the local oscillating light to obtain two polarized components; a detecting circuit (9) for detecting the polarized component to output intermediate frequency signals (e.sub.S and e.sub.P); and a frequency control circuit (11) for controlling, in accordance with the intermediate frequency signals (e.sub.S and e.sub.P), the oscillating frequency of the optical local oscillating circuit (7). To ensure that the intermediate frequency does not disappear, the frequency control circuit (11) outputs a combined signal of a sum and a difference of the intermediate frequency signals (e.sub.S and e.sub.P). 
Fujitsu Limited
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inventional inventional inventional
Hideo Hiroshi Takao Tetsuya Hideyuki Yoshihito Shigeki Terumi
Kuwahara Onaka Naito Kiyonaga Miyata Onoda Watanabe Chikama