| 摘要 |
<p>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: an input optical waveguide (11); a first optical coupler (12) connected to the input optical waveguide (11); a pair of optical-waveguide arms (13a, 13b) connected to the output of the first optical coupler; and a second optical coupler (18) connected to the pair of optical-waveguide arms (13a, 13b). A groove (15) is formed in a manner so as to traverse the pair of optical-waveguide arms (13a, 13b). 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. The first optical coupler (12), which provides a phase difference of 0 degrees or 180 degrees between beams of light that are coupled and branched, is used in combination with the second optical coupler (18), which provides a phase difference of 90 degrees or -90 degrees between the beams of light that are coupled and branched.</p> |
