| 摘要 |
PURPOSE:To minimize the bending loss in the joint part between the bent part and straight part of waveguides by loading a thin dielectric film to said joint part. CONSTITUTION:The straight waveguide 3 and the curved waveguide 5 are joined and the thin dielectric film 4 having a prescribed propagation constant is loaded to the joint part. the propagation constant Bm in the joint part is arbitrarily set according to the thickness of the thin film 4 if the refractive indices of the waveguides 3, 4 are assumed to be the same and the propagation constants in the waveguides 3, 5 are respectively designated as B1, B2. The loss in the joint part is minimized by selecting the thickness of the film 4 so as to attain Bm=(B1B2)<1/2>. |
