| 摘要 |
PURPOSE:To prepare an optical filter by a process for forming a semiconductor light emitting element or a light receiving element by forming plural numbers of groove having deeper depth than the thickness of a waveguide with a desired spacing of period and a desired width along the propagation direction of light, and embedding film comprising a material having a different refractive index from the refractive index of the waveguide layer in the groove. CONSTITUTION:A substrate 1 comprises a semiconductor, ferroelectric body, magnetic body, or glass, and a waveguide layer 3 is formed interposing a clad layer 2. The refractive index of the clad layer 2 is smaller than the refractive index of the waveguide layer 3. Layers 4-1-4-m having smaller refractive indices than the waveguide 3 are formed with ca. n/2 wavelength spacings. In order to reduce radiation loss at the respective parts, the refractive indices of the layers 4-1-4-m are preferred to be larger than the refractive index of the clad layer. The width of the layers 4-1-4-m are regulated to ca. n/4 of the wavelength. |
