WAVEGUIDE TYPE OPTICAL CIRCUIT

摘要

PROBLEM TO BE SOLVED: To provide a waveguide type optical circuit capable of eliminating high-order modes efficiently even when impurity layer high in refractive index are formed at the boundary between core and clad by manufacturing deviation caused in a manufacturing process. SOLUTION: In this waveguide type optical circuit 13 in which an optical waveguide 8 consisting of core and clad is formed by laminating quarze-contg. glass on a silicon substrate, a mode filter 22 formed so that its width is narrower than that of the optical waveguide 8 is provided at one part of the waveguide 8. Thus, even though an optical axis deviation is caused when elements such as LD, PD are mounted on the waveguide type optical circuit 13 and high-order modes is caused, the mode is eliminated with the mode filter 22.