WAVEGUIDE-TYPE POLARIZATION BEAM SPLITTER

摘要

Provided is a waveguide-type polarization beam splitter in which deterioration of a polarization extinction ratio due to temperature change and wavelength change is suppressed. The waveguide-type polarization beam splitter includes: an input optical waveguides (11); a first optical coupler (12) coupled to the input optical waveguides (11); a pair of optical waveguide arms (13a, 13b) coupled to outputs of the first optical coupler; and a second optical coupler (18) coupled to the pair of optical waveguide arms (13a, 13b). A groove (15) is formed to extend across the pair of optical waveguide arms (13a, 13b) and two quarter wave plates (16a, 16b) are provided in the groove (15) to extend respectively across the arms (13a, 13b). Polarization axes of the quarter wave plates (16a, 16b) are orthogonal to each other. The first optical coupler (12) which gives a phase difference of 0° or 180° between coupled or split light beams and the second optical coupler (18) which gives a phase difference of 90° or -90° between coupled or split light beams are used in combination.