Abstract: A first core layer and a second core layer, serving as optical waveguides, whose refractive indexes are greater than that of a substrate are placed on the surface of the substrate that functions as a cladding layer. An interval between the first core layer and the second core layer is partially narrowed so that lightwaves progressing through these core layers may develop an optical mode coupling. Disposed in this optical mode coupling area is a detector, which comes in contact with liquid or gas and interacts with a substance to be detected, such as chemical or biological substance. A receptor material which selectively captures the substance to be detected is fixed on a surface of the detector. Antibody, enzyme, cell, ionophore, single-strand DNA and the like are examples of the receptor material.

Abstract: A first core layer and a second core layer, serving as optical waveguides, whose refractive indexes are greater than that of a substrate are placed on the surface of the substrate that functions as a cladding layer. An interval between the first core layer and the second core layer is partially narrowed so that lightwaves progressing through these core layers may develop an optical mode coupling. Disposed in this optical mode coupling area is a detector, which comes in contact with liquid or gas and interacts with a substance to be detected, such as chemical or biological substance. A receptor material which selectively captures the substance to be detected is fixed on a surface of the detector. Antibody, enzyme, cell, ionophore, single-strand DNA and the like are examples of the receptor material.

Abstract: A high breakdown voltage semiconductor device is formed in a desired region on a semiconductor substrate. An impurity diffusion layer 32 is disposed at the center of the high breakdown voltage semiconductor device. The impurity diffusion layer 32 has a rounded or semi-circular configuration at both ends thereof having a particular curvature. The impurity diffusion layer 32 serves as drain. An impurity diffusion layer 33 is formed in the neighborhood and periphery of the impurity diffusion layer 32. The width of a portion 33b of the impurity diffusion layer 33 in abutting relation with the two semi-circular end portions of the impurity diffusion layer 32 is wider than that of a remaining portion 33a of the impurity diffusion layer 33 in abutting relation with longitudinal sides of the impurity diffusion layer 32. The rounded end portions of the impurity diffusion layer 32 have a larger curvature than the longitudinal side portions thereof.