562015-03-24 , 法政大学大学院理工学・工学研究科
An reasonably accurate technique for evaluating the properties of asymmetric waveguide-type polarization converters is proposed, in which only the eigenmode fields are used to calculate the full-vectorial overlap integral. A butt joint between slot and Si-wire waveguides is investigated by the imaginary-distance beam propagation method based on Yee’s mesh and finite-difference time-domain method. This structure transforms a slot waveguide into a Si-wire waveguide, while converting the polarization. An extinction ratio of more than 15 dB is obtained with a relatively low loss of 1 dB over a wavelength range of 1.53 μm to 1.58 μm.