| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a reflection type optical communication system utilizing polarized waves, and a station and a user terminal used therefor, capable of carrying out transmission and reception of optical signals with high quality by suppressing the effect of the Rayleigh scattering caused between the uplink and downlink optical signals. <P>SOLUTION: The station K transmits a continuous light Pc and a downlink optical signal Pd to the user terminal U via an optical fiber 104. In this case, the polarization direction of the continuous light Pc is differentiated from that of the downlink optical signal Pd. A downlink optical signal receiver 107 of the user terminal U receives the downlink optical signal Pd. Further, an optical limiter amplifier 114 decreases the extinction ratio of the downlink optical signal Pd. A reflection type optical modulator 106 modulates the continuous light Pc to generate an active uplink optical signal Pu1 and modulates the downlink optical signal Pd the extinction ratio of which is decreased to generate a standby uplink optical signal Pu2. The two optical signals Pu1, Pu2 are transmitted to the station K wherein an uplink optical signal receiver 108 receives the signals. Even if the polarization direction of either of the uplink optical signals Pu1, Pu2 is coincident with that of the down link optical signals Pc, Pd and the waveform is disturbed by the Rayleigh scattering, the polarization direction of the other of the uplink optical signals Pu1, Pu2 is not coincident with the polarization direction of the downlink optical signals Pc, Pd, thereby enabling excellent signal transmission. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
