| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a small-sized polarization state measuring instrument capable of measuring precisely a polarizing state of an input signal light, by correcting differences in arrival times of the signal light up to photoreception elements caused by a difference in optical path lengths of a plurality of branched optical paths. <P>SOLUTION: In this polarization state measuring instrument, the input signal light L<SB>IN</SB>is branched into four signal lights by photocouplers 1A-1C constituted in 3 stages, different polarizations and phase differences are imparted to the respective signal lights by the plurality of optical elements arranged on the respective branch paths, respective signal light powers are detected by corresponding photoreception elements 4<SB>1</SB>to 4<SB>4</SB>, and electric signals output from the respective photoreception elements 4<SB>1</SB>to 4<SB>4</SB>are processed after regulating at least the differences in the optical path lengths of the respective branched optical paths, in a computing means 30, so as to acquire information as to the polarization state of the input signal light L<SB>IN</SB>. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
