| 摘要 |
PURPOSE:To efficiently couple each optical device, or elements in an optical integrated circuit, by providing an incident end whose thickness becomes thin gradually, or an exiting end whose thickness becomes thick gradually, which is placed on the same optical axis. CONSTITUTION:With respect to an optical waveguide, an area of an end face is enlarged in the coupling part of an optical fiber and an element, and also, the optical waveguide is removed so that the optical path length of the interval of a flat end face of an element in an optical integrated circuit becomes about the integer multiple of half of the wavelength to be used. In such a way, since the waveguide is widened in the thickness direction in a coupling part to the optical fiber, coupling can be easily executed. Also, in the case of removing the optical waveguide, the effective refractive index of the optical waveguide of the element and the effective refractive index of an optically coupled element are aligned to the same degree, an air-gap between the optical waveguides of these two elements becomes an etalon and handled as a general multiple reflection, therefore, when the optical path length of this air-gap is the integer multiple of half of the wavelength, in the case of a plane wave, a reflection factor becomes '0', and the coupling efficiency of 100% can be obtained. |
