| 摘要 |
PROBLEM TO BE SOLVED: To provide a wavelength-plate-inserted polarization beam splitter that realizes ideal interference conditions and a high polarization extinction ratio even in the event of an unexpected phase error caused by variation of core width during manufacture of cores, uneven distribution of stress on an over-cladding layer, or the like.SOLUTION: A polarization beam splitter 1 has two wavelength plates 12, 13 whose thicknesses are chosen to compensate for a phase error that occurs during manufacturing steps between arm waveguides 3, 4. After the polarization beam splitter circuit 1 is manufactured, the phase error between the waveguides is measured in one way or another and two wavelength plates 12, 13 having appropriate thicknesses are selected. A plurality of types of wavelength plates having a certain range of thicknesses are prepared in advance, and wavelength plates 12, 13 having thicknesses closest to calculated values are selected and mounted in a groove 11. |
