| 摘要 |
PURPOSE:To miniaturize an optical switch while reducing its loss by constituting optical waveguides which connect respective terminals by linear optical waveguides, and sticking a material which controls a refractive index on a groove formed at each branch part and determining the branching ratio of the branching part. CONSTITUTION:A substrate 8 is made of n-InP and a clad layer of n-InP, an active layer of InGaAsP, a clad layer of p-InP, and a gap layer of n-InP are grown by liquid-phase epitaxial growth as well as a normal laser diode to manufacture a wafer in double hetero-structure. In this case, the composition ratio of the active layer is controlled to control the in-use wavelength of the optical switch. Then waveguide patterns and grooves are formed at the same time by using gaseous BCI3 and materials which control the refractive index are stuck on the wall surfaces of the grooves. An Si3N4 film is used so as to obtain a 1:1 branching ratio and stuck while controlled to a 2.95 refractive index when the wavelength is 1.3mum. Thus, the voltage division ratio of N2 of Si3N4 is varied optionally to vary the branching ratio from 100 to 10% option ally, thereby attaining integration to small size. |
