MEASURING DEVICE HAVING OPTICAL BOUNDARY SURFACE IN WHICH POLARIZATION DEPENDENCE LOSS (PDL) IS REDUCED

摘要

PROBLEM TO BE SOLVED: To provide an optical measuring device in which the effect of reflection attenuation and a polarization dependence loss is reduced.;SOLUTION: The optical measuring device 70 which is provided with an optical fiber 30 and a photodetector 60 which is constituted so as to measure an incident light signal 75 by receiving it from the optical fiber 30 is disclosed. The optical fiber 30 and/or the photodetector 60 is provided with an interface 50 preferably being a boundary surface, a surface or a facet, between optical media having different refractive indexes. The interface 50 is arranged by being inclined with respect to the incident light signal 75 in order to reduce return reflection heading toward the direction of the signal 75. Since the transmissivity Ts of the light palarized vertically to the incident plane of the signal 75 is roughly equal to the transmissivity Tr of the light palarized parallel with the incident plane of the signal 75, thus the transmissivity of the signal 75 passing through the interface 50 does not depend upon the polarization state of the signal 75 substantially.;COPYRIGHT: (C)2000,JPO