title: Control of radiation angle by introducing symmetric end structure to oblique waveguide in three-dimensional photonic crystal.
abstract: We investigate the radiation angle of an oblique waveguide in a stripe-stacked three-dimensional photonic crystal. We show that the output-light is radiated in a different direction from the oblique waveguide direction. Moreover, the radiation polar angle varies from 30° to 50° depending on the frequency. To inhibit the frequency dependence and obtain vertical radiation, we introduced a symmetric structure at the end of the waveguide. As a result of cancellation of the in-plane asymmetric wavenumber, the radiation polar angle is less than 6° from the surface-normal direction and does not depend on frequency.
authors.forename: Kou
authors.initials: K
authors.lastname: Gondaira
authors.forename: Kenji
authors.initials: K
authors.lastname: Ishizaki
authors.forename: Keisuke
authors.initials: K
authors.lastname: Kitano
authors.forename: Takashi
authors.initials: T
authors.lastname: Asano
authors.forename: Susumu
authors.initials: S
authors.lastname: Noda