Patent ID: 7369232

Claim:
A Stokes parameter measurement device, comprising: an incidence portion, on which the signal light to be measured is incident; an optical splitter portion, which splits signal light which has passed through said incidence portion into at least four rays; a phase compensation portion, which endows each of the split signal light rays with different polarizations and phases; and, a photodetector circuit portion, which performs photoelectric conversion of the optical component of the signal light rays emitted from the phase compensation portion; said optical splitter portion has at least one prism, said at least one prism has a plurality of faces containing an edge formed therein, the angles which are generated by said plurality of faces and the optical axis of said signal light are larger than 45° respectively, and the signal light, having passed through said incidence portion, is caused to be incident on said plurality of faces to split the signal light.