| 摘要 |
PROBLEM TO BE SOLVED: To reduce an influence of a refractive index difference caused by photoabsorption between an n-type semiconductor substrate and a high-resistance embedded layer to be exerted on the photointensity distribution between an n-type semiconductor substrate and a high-resistance embedded layer. SOLUTION: A tapered waveguide part in which a size of a core layer 2, consisting of more than one layer for waveguiding of light inside a resonator is continuously decreased to an outgoing end face 5 of light, is integrated on an n-type semiconductor substrate 1. Now, along with at least making both sides of the core layer 2 to come in contact with a high-resistant semiconductor layer 4, out of the boundary surface between the n-type semiconductor substrate 1 and the high-resistant semiconductor layer 4, a distance between a part almost in parallel with the main surface of the n-type semiconductor substrate 1 at least in the outgoing end face 5 and the lower end of the core layer 2 is made not less than 2μm. |
