| 摘要 |
PURPOSE:To improve the utilization efficiency of light and facilitate optical axis alignment by forming light waveguide layers which vary in equivalent refractive index in the traveling direction of the light on both surfaces of a substrate which transmits light. CONSTITUTION:The waveguide layers 2 and 4 which vary in equivalent refractive index in the traveling direction of the light are formed on both sides of the substrate 3 which has light transmissivity. The 1st optical waveguide layer 2 and 2nd optical waveguide layer 4 decrease in thickness in a tapered shape toward a substrate end part 3a and called a 1st tapered coupler 2a and a 2nd tapered coupler 4a. The light is guided into the 1st optical waveguide layer 2 and propagated in the layer, but when it is propagated to the 1st tapered coupler 2a, it is emitted gradually to the side of the substrate 3 and emitted out of the substrate end part 3a. The light which enters the 2nd tapered coupler 4a from the substrate end part 3a is converted to the waveguide mode of propagation in the 2nd optical waveguide layer 4. Consequently, a high-efficiency input/output coupler is realized and the optical axis alignment is facilitated. |
