Abstract: A light receiving structure for waveguide type optical devices, which excels in productivity, is compactly formed and permits highly efficient coupling, is provided. A recess is provided in part of the surface of a substrate on which an optical waveguide is formed, and a light-receiving element is mounted on the recess, with its light-receiving face upward. Near the recess is formed an end face of the optical waveguide in advance, so that a light be emitted therefrom. On the other hand, over the substrate is arranged a cover in which a groove is formed in a position opposite to the optical waveguide and a reflector is formed in a position opposite to the light-receiving element. The light emitted from the optical waveguide is reflected by the reflector and coupled to the light receiving element.

Abstract: In an optical semiconductor module having an optical semiconductor chip mounted on a substrate through a plurality of solder bumps each of which has a predetermined height and which is formed by molten solder, each of the bumps is surrounded by a side wall lower than the predetermined height of each bump. The optical semiconductor chip is precisely positioned on the substrate not only in a horizontal direction by self-alignment effect of the molten solder but also in a vertical direction due to shrinkage of the molten solder with a bottom surface of the optical semiconductor chip kept contact with upper surface of the side walls, upon cooling the molten solder.

Abstract: In an optical device comprising a substrate and a package for receiving the substrate on a bottom surface of the package, a block is fixed to an upper surface of the substrate by a low melting-point glass or a solder. The block is made of a welding material and welded to a predetermined part on a wall surface of the package. The substrate has at least one photoelectric element or optical waveguide on the upper surface. An optical fiber is fixed to the package and optically coupled to the photoelectric element or the optical waveguide through a first perforation of the package. The block may be welded to the wall surface of the package made of a welding material. The substrate may have an internal surface which defines a second perforation exposing a predetermined area of the bottom surface. The block is brought into contact with the second internal surface and the predetermined area and welded to the predetermined area.

Abstract: In an optical semiconductor module having an optical semiconductor chip mounted on a substrate through a plurality of solder bumps each of which has a predetermined height and which is formed by molten solder, each of the bumps is surrounded by a side wall lower than the predetermined height of each bump. The optical semiconductor chip is precisely positioned on the substrate not only in a horizontal direction by self-alignment effect of the molten solder but also in a vertical direction due to shrinkage of the molten solder with a bottom surface of the optical semiconductor chip kept in contact with an upper surface of the side walls, upon cooling the molten solder.

Abstract: An optical module comprises a capillary in which first and second optical fibers are connected. The first optical fiber is aligned through a lens to an optical device, and the second optical fiber functions as a pigtail cord connected to an external optical fiber. The first optical fiber is a TEC (thermal expand core) fiber having an end portion whose core diameter is larger than that of the other portion thereof, and the first optical fiber is a normal optical fiber which has a uniform core diameter smaller than the core diameter of the TEC fiber.

Abstract: Optical fiber connector comprises a ferrule receiving an optical fiber and a sleeve member for holding the ferrule. The body of the ferrule is made of glass on which a thin layer is deposited for reinforcement of the body. The thin layer may be made by hydrolysis, chemical vapor deposition, spray coating etc. The ferrule of the optical fiber connector is inexpensive, easy to assemble and suitable for mass production.

Abstract: In an optical waveguide device, a plurality of optical directional coupler switches are provided on a substrate, and light input and output terminals are also provided to be coupled to the optical directional coupler switches. Each of the optical directional coupler switches is provided with a pair of parallel waveguides. One of the optical directional coupler switches operates independently of the polarization of light having a first predetermined wavelength by defining a width of the parallel waveguides and a distance therebetween to be first predetermined values, and one of the optical directional coupler switches operates independently of the polarization of light having a second predetermined wavelength by defining a width of the parallel waveguides and a distance therebetween to be second predetermined values.