| 摘要 |
PURPOSE:To allow optical receiving with high sensitivity by consisting a locally generated light emitting means of 1st and 2nd light sources which respectively emit the light beams having the planes of polarization intersecting orthogonally with each other and using an optical multiplexing section which receives these light beams as the locally generated light. CONSTITUTION:The locally generated light having the linearly polarized light emitted from the 1st locally generated light source 1 is coupled to one input end of a 3X3 optical fiber coupler 4 as the optical multiplexing section. The output of the 2nd locally generated light source 2 is so adjusted in the polarization state as to intersect orthogonally with the 1st locally generated light and is then coupled to the other input terminal of the coupler 4. Signal light 3 is inputted from the remaining terminal of the coupler 4. The outputs of 1st and 2nd demodulating circuits 14, 15 are synthesized by a synthesizer 16, by which the specified demodulated output is obtd. even if there is a fluctuation in the polarization of the signal light. The optical receiver which is not affected by the fluctuation in the polarization and has the high sensitivity is obtd. in this way. |
