POLARIZATION MODE CONVERTER

摘要

A polarization mode converter which is provided in a two-dimensional photonic crystal or which can be connected smoothly therewith. In the two-dimensional photonic crystal where a large number of regions (e.g. holes (22)) having a refractive index different from that of a slab-like main body are arranged in lattice in the main body, a polarization conversion waveguide (23) having a defect of different refractive index region formed linearly and a cross-sectional profile asymmetric in the vertical and horizontal directions is provided. The polarization conversion waveguide (23) can be formed by providing holes (221, 222) extending obliquely to the surface of the main body, for example, on the side portion of the waveguide. A TE polarized wave propagating through the polarization conversion waveguide (23) is partially converted into a TM polarized wave by the asymmetric cross-sectional profile of the waveguide. Since the polarization mode converter is composed of the two-dimensional photonic crystal, it can be provided in the two-dimensional photonic crystal or can be connected smoothly therewith.