| 摘要 |
PURPOSE:To enable the large deflection in a perpendicular direction and to make the above element higher in speed and smaller in size by providing a grating coupler consisting of a specific inclined grating. CONSTITUTION:A thin-film optical waveguide 2 is formed on the surface of a substrate 1 and a light introducing part for making a light beam incident form one side of this thin-film optical waveguide 2 is formed. An intra-surface deflecting means for deflecting the guided light introduced therein within the plane parallel with the thin-film optical waveguide 2 is provided. The grating coupler 4 consisting of the inclined grating of the direction diagonally crossing the direction orthogonal with the incident direction of the incident light is provided on the extension in the propagating direction to the light introducing part. This coupler is so constituted as to satisfy equation when the angle of the intra-surface deflection is designated as alpha, the angle of inclination of the grating with the direction orthogonal with the incident direction of the incident light as PHI, the effective refractive index of the optical waveguide as N, the wavelength of the incident light as lambda the period of the grating as LAMBDA, and the refractive index of the exit medium as n. In the equation, q is an integer which is no 0. |
