| 摘要 |
PROBLEM TO BE SOLVED: To reduce the light loss at the part where linear waveguides cross each other. SOLUTION: A linear waveguide composed of an InP lower clad layer 2, an InGaAsP core layer 3 and an InP upper clad layer 4, is provided with an InGaAsP high-refractive-index imparting layer 5, the equivalent refractive index of the center part in the core of the linear waveguide is set higher than that nearby the clad at the peripheral part in the core to vary the electric field distribution of propagated light, and the light is made hard to spread at the intersection part, thereby reducing the light loss at the parts where linear waveguides cross each other. |
