WAVEGUIDE-TYPE POLARIZATION BEAM SPLITTER

摘要

Provided is a waveguide-type polarization beam splitter in which degradation in polarization extinction ratio due to changes in temperature and wavelength is inhibited. The waveguide-type polarization beam splitter includes: input optical waveguides (11); a first multimode-interference optical coupler (12) connected to the input optical waveguides (11); a pair of optical-waveguide arms (13) connected to the output of the first multimode-interference optical coupler (12); a second multimode-interference optical coupler (18) connected to the pair of optical-waveguide arms (13); and output optical waveguides (19a, 19b) connected to the output of the second multimode-interference optical coupler (18). A quarter-wave delay (22) is provided to one optical-waveguide arm (13b). A groove (15) is formed in a manner so as to traverse both of the optical-waveguide arms (13). The groove (15) is provided with two quarter-wave plates (16a, 16b) in a manner so at to traverse the arms (13a, 13b) respectively. The respective polarization axes of the quarter-wave plates (16a, 16b) are orthogonal to one another.