Abstract: A light-sensitive detector (1) according to the present invention is constituted by an array (11) of photodetectors, a package (13) on which the array (11) of photodetectors is mounted, and a light-transmissible window (12) for making detection light incident on light-receiving surfaces of the photodetectors. The package (13) is provided with an aperture (14) which is formed in a position adjacent to the photodetectors so that light rays substantially parallel to the detection light can pass through the aperture (14).

Abstract: An optical module is provided in which recesses are formed in a sol-gel layer applied to a surface of a lens array substrate, each of the recesses having a capability to fit an optical fiber therein. The optical module comprises a planar microlens array substrate having a plurality of microlenses formed in one surface thereof; and an alignment recess array including a plurality of alignment recesses which are formed in a material applied to the other surface of the microlens array substrate by means of a mold with the center of each alignment recess being aligned to the center of a corresponding one of the microlens. The optical module may comprise a plurality of optical fibers each end thereof is adhered to the alignment recesses.

Abstract: An optical module is provided in which any conjugate ratio in an optical axis direction may be easily realized, the time duration for alignment may be shortened by using a passive alignment technique, and a large degree of may be obtained for any optical design. The optical module comprises a planar microlens array, a transparent substrate for adjusting a conjugate ratio of the optical module, and a guide substrate for optical fibers. The planar microlens array consists of a planar transparent substrate, in one surface thereof a plurality of circular microlenses are formed and arrayed. The transparent substrate includes a plurality of micro fitting recesses formed and arrayed in one surface thereof. The guide plate includes a plurality of micro guide holes opened therethrough.

Abstract: The invention provides a multilayer-coated substrate which has recesses and projections of an accurate shape on the surface and has high heat resistance and a high degree of integration, and further provides a process for producing the same.

Abstract: An optical connection device according to the invention is an optical connection device for optically coupling light propagated through an optical waveguide to an optical element arranged outside the optical waveguide and with the following configuration. Part of the optical waveguide is removed so as to be shaped like a groove. The optical waveguide and the optical element are arranged so that an optical axis of the optical waveguide intersects an optical axis of the optical element at a specified angle inside the groove. An optical unit is arranged at a position of intersection of the optical axes for turning light by reflection from one optical axis along the other optical axis.

Abstract: In the light-receiving element array device according to the present invention, a light-receiving section can be arranged at a position close to an input optical fiber so that the light-receiving element array device can be used as an optical demultiplexer based on the Littrow arrangement. Further the present invention enables suppression of coma aberration and minimization of an optical demultiplexer by shortening a length of the optical system. To achieve the above-described object, a rectangular chip having a light-receiving section with a number of light-receiving elements arrayed in row thereon is sealed in a rectangular package having external leads and the bonding pads on the chip and the bonding terminals of the packages are connected with a bonding wire or the like.

Abstract: The present invention relates to a method of aligning and assembling an optical demultiplexer module having an input fiber, a collimator lens, a diffraction grating, and a photodetector array, and a mechanism for automatically aligning such an optical demultiplexer module. The method comprises the steps of preparing a submodule A including the input fiber and the photodetector array and a submodule B including the diffraction grating and the collimator lens, preparing an alignment jig for allowing the submodules A, B to move independently of each other, fixing the submodules A, B to the adjustment jig, and applying light from the input fiber and moving the submodule B with respect to the submodule A for maximizing a light output from a photodetector.

Abstract: When a diffraction grating having a grating period of d and a diffraction order of m for an incident light having a wavelength interval &Dgr;&lgr;i between i'th and (i+1)'th channels is used, an optical path length between the diffraction grating and the photodetector is represented by L and a mean output angle is represented by &thgr;o, a pitch pi between the i'th and (i+1)'th photodetectors in the photodetector array satisfies the equation of pi=m&Dgr;&lgr;iL/d cos &thgr;o.

Abstract: A diffraction optical element including an element body having a large number of grooves formed on its surface to form a grating, and a grating shape adjusting layer deposited on a grating surface of the element body by oblique incidence or material particles onto the grating surface, wherein the grating shape adjusting layer per se is made of a reflecting film material By the grating shape adjusting layer, the contour shape of the resulting grating surface in a section perpendicular to a lengthwise direction of the grooves is made not similar to the sectional shape of the element body. A reflecting film may be formed on a grating shape adjusting layer made of another material. A reflecting film may be provided on the element body before a grating shape adjusting layer made of a transparent dielectric material is provided on the reflecting film.

Abstract: An optical module according to the invention includes an optical fiber, a planar lens, and a flat plate-like transparent member for optically coupling the optical fiber and the planar lens to each other. The transparent member has a nearly spherical concave portion formed in a surface of the transparent member. An end surface of the optical fiber is inserted into the concave portion of the transparent member so as to abut thereon and bonded and fixed thereinto. Further, a surface of the transparent member opposite to the surface in which the concave portion is formed is joined to a surface of the planar lens to make an optical axis of the optical fiber coincident with an optical axis of the planar lens. The concave portion is filled with a filler material having a refractive index higher than that of the transparent member to thereby fix the optical fiber.

Abstract: An optical element having a wavelength selectivity, which is easy to manufacture and reduces the manufacturing cost. The optical element comprises a light guide plate (22) having opposing two end faces (22a, 22b), and a multilayered film filter (23) formed on at least one of the opposing two end faces of the light guide plate. The multilayered film filter includes high-refractive-index dielectric layers and low-refractive-index dielectric layers laminated alternately and its thickness continuously changes in accordance with a position of the associated end face of the light guide plate. The center wavelength of transmitted light from the multilayered film filter differs in accordance with the position of the end face of the light guide plate. In a case where mixed light is input to the multilayered film filter from individual lenses via the light guide plate, the mixed light is separated to lights of different center wavelengths by the multilayered film filter that has different thicknesses.

Abstract: A waveguide type liquid-crystal optical switch including: an optical waveguide having a pair of first and second cores close to each other for switching an optical path between the pair of first and second cores; a third core made of nematic liquid crystal enclosed in between a pair of oriented films and oriented in a predetermined direction by the pair of oriented films, the third core being disposed in any one of a space covering the first and second cores in parallel with a plane containing optical axes of the first and second cores, a space sandwiched between the first and second cores and a space covering upper surfaces of the first and second cores so as to be laid over the first and second cores; a first electrode disposed on a surface of the third core opposite to the first and second cores so as to cover a gap portion between the first and second cores; second and third electrodes disposed as a pair, between which electrodes the first electrode is put, the second and third electrodes provided for ori

Abstract: Incident light rays (11) given from an optical fiber (10) are converted into parallel light rays (12) by a collimator lens (2). The parallel light rays (12) are demultiplexed in accordance with wavelengths by a diffraction grating (3). After the demultiplexed light rays arrive at the collimator lens (2) again, the light rays are converted into convergent light rays (14) and converged into a photo acceptance element array. Because the converging/image-forming positions of respective channels are arranged at irregular pitches in accordance with wavelengths, signals of the channels can be taken out accurately and efficiently from photo acceptance elements respectively when the photo acceptance elements are provided in the converging/image-forming positions respectively.

Abstract: An optical module includes a package, which accommodates an optical system. A package main body has an opening. A lid is attached to the main body to close the opening of the main body. The lid seals the package. An anti-deterioration agent for preventing deterioration of the optical system is located inside the package at a position out of a light path of the optical system. The anti-deterioration agent includes at least one of desiccant and deoxidant.

Abstract: When an end surface of a silica optical fiber and another optical element are to be optically coupled to each other, according to the invention, the optical fiber is treated so that a core of the optical fiber is protruded from a clad of the optical fiber at an end portion of the optical fiber to form a protrusion shaped like a truncated cone or like a cone. On this occasion, the refractive index of the surrounding medium is selected to be in a range of from 1.35 to 1.60. Preferably, the area of the top surface of the truncated cone is not larger than ⅕ as large as the area of the bottom surface of the truncated cone. Further preferably, the side surface of the core protrusion is inclined at an angle of 30 degrees to 75 degrees, both inclusively, with respect to the central axis of the core.

Abstract: A molding die having satisfactory releasability, a sol-gel composition produced using the molding die, and a process for producing a sol-gel composition. The molding die which is to be pressed against a sol-gel material for producing a sol-gel composition has a release film, e.g., a thin gold (Au) film, formed on the molding surface of the molding die through a buffer layer made of metals and/or inorganic oxides.

Abstract: A molding die having satisfactory releasability, a sol-gel composition produced using the molding die, and a process for producing a sol-gel composition. The molding die which is to be pressed against a sol-gel material for producing a sol-gel composition has a release film, e.g., a thin gold (Au) film, formed on the molding surface of the molding die through a buffer layer made of metals and/or inorganic oxides.

Abstract: A molding die having satisfactory releasability, a sol-gel composition produced using the molding die, and a process for producing a sol-gel composition. The molding die which is to be pressed against a sol-gel material for producing a sol-gel composition has a release film, e.g., a thin gold (Au) film, formed on the molding surface of the molding die through a buffer layer made of metals and/or inorganic oxides.

Abstract: A molding die having satisfactory releasability, a sol-gel composition produced using the molding die, and a process for producing a sol-gel composition. The molding die which is to be pressed against a sol-gel material for producing a sol-gel composition has a release film, e g., a thin gold (Au) film, formed on the molding surface of the molding die through a buffer layer made of metals and/or inorganic oxides.

Abstract: A light-receiving element is provided, which may easily detect the barycenter of a light intensity of light having a long-wavelength band in an optical communication. An InGaAs layer (i-type layer) and a p-type InP layer are stacked on an n-type InP substrate. Electrodes are formed on both sides of the top surface of the p-type layer, and an electrode is formed on the bottom surface of the n-type substrate. An incident light impinged upon the light-receiving element is photoelectric-converged into a photocurrent, and the photocurrent flows in the p-type layer to the electrodes. As a result, a current is derived from each of the electrodes, the magnitude thereof being dependent on the distances from the light impinging position to respective electrodes. The barycenter of a light intensity may be calculated from the currents derived from the electrodes and a light intensity may be obtained from the summation of the currents.