| 摘要 |
PROBLEM TO BE SOLVED: To optically couple an optical waveguide and a photodetector 6 with high efficiency and to lower the reflected return light to the optical waveguide. SOLUTION: A V-groove 8 is so formed as to cross the core part 4 of the optical waveguide 1. The surface on the side where the guided light of the V-groove 8 is emitted is formed nearly perpendicularly to the substrate surface and the opposite surfaces thereof are formed to incline with about 45 deg.. Total reflection coating 10 is formed on the inclined surface 9. The guided light is reflected upward and is coupled to the photodetector 6 arranged in the upper part of the optical waveguide 1 by directing its photodetecting surface 7 downward. At this time, a refractive index matching agent 11 having nearly the same refractive index as the refractive index of the core 4 of the optical waveguide 1 is packed between the V-groove 8 and the photodetector 6. The guided light emitted from the optical waveguide 1 is coupled to the photodetector without passing the reflection surface and, therefore, the coupling with the high efficiency and low reflection is made possible. The coupling structure may be provided with a lens effect as well by forming the surface of the refractive index matching agent 11 to a convex shape by utilizing its surface tension. |
