| 摘要 |
PURPOSE:To hardly occur crosstalk and to facilitate the optimization of branching ratio for an optical coupler by slanting a polarized light separation direction at a specific angle to a yz plane. CONSTITUTION:The optical receiver for coherent light wave communication provided with an optical coupler 2, a polarization beam splitter 18, and a photodetector 28 having 1st-4th photodetection parts 20, 22, 24, and 26 is constituted so that a plane containing the main axes of 1st and 2nd mutually parallel polarized light beams 106 and 108 and a plane containing the main axes of 3rd and 4th mutually parallel polarized light beams 110 and 112 slant at almost 45 to a plane (yz plane) containing the main axes of 1st and 2nd branch light beams 102 and 104. The four photodetection parts 20, 22, 24, and 26 are therefor positioned at the respective vertices of a parallelogram having no 90 vertical angle. Consequently, when two double balanced type photodetectors are constituted, their signal lead-out points do not face each other, crosstalk is hardly generated, and the branching ratio is optimized. |
