Abstract: An optical module according to the invention can achieve an optical system using a transmission-type diffraction grating for bending the optical path of incident light with a specific wavelength by about 90°. A substrate of the transmission-type diffraction grating is mounted at an angle in a range of +5° with respect to the design incident angle ? of the incident light. The optical system can be applied to a light multiplexing/demultiplexing module.

Abstract: An optical module can achieve an optical system using a transmission-type diffraction grating for bending the optical path of incident light with a specific wavelength by about 90°. A substrate of the transmission-type diffraction grating is mounted at an angle in a range of ±5° with respect to the design incident angle ? of the incident light. The optical system can be applied to a light multiplexing/demultiplexing module.

Abstract: A transmission diffraction optical element is presented in which ridges having a roughly rectangular cross-section shape are disposed parallel to each other at a regular pitch at the surface of a substrate. Striped thin-film layers are formed on these ridges and a thin-film layer is inserted between the substrate and the ridges. The thin-film layers are arranged at a regular pitch identical to the regular pitch of the ridges and the thin-film layer does not have a periodic pattern oriented in the same direction as the periodic pattern of the ridges.

Abstract: A transmission diffraction optical element is presented in which ridges having a roughly rectangular cross-section shape are disposed parallel to each other at a regular pitch at the surface of a substrate. Striped thin-film layers are formed on these ridges and a thin-film layer is inserted between the substrate and the ridges. The thin-film layers are arranged at a regular pitch identical to the regular pitch of the ridges and the thin-film layer does not have a periodic pattern oriented in the same direction as the periodic pattern of the ridges.

Abstract: A transmission diffraction optical element is presented in which ridges having a roughly rectangular cross-section shape are disposed parallel to each other at a regular pitch at the surface of a substrate. Striped thin-film layers are formed on these ridges and a thin-film layer is inserted between the substrate and the ridges. The thin-film layers are arranged at a regular pitch identical to the regular pitch of the ridges and the thin-film layer does not have a periodic pattern oriented in the same direction as the periodic pattern of the ridges.

Abstract: A light measuring device is designed, so that excitation light, emitted by a light source, is guided through an excitation light optical fiber to irradiate a sample, and that fluorescence discharged by the sample is guided to an optical detection system through a receiving light optical fiber. A coupling lens is arranged ahead of the excitation light optical fiber and ahead of the receiving light optical fiber on the sample side. A sample container for retaining a sample is so designed that a lens portion, for collecting excitation light and fluorescence, is integrally formed with the cylindrical bottom. According to this arrangement, excitation light is changed to parallel light or converged light by the coupling lens, and is collected at the sample by the lens portion integrally formed with the bottom of the sample container.

Abstract: A transmission grating that provides low polarization dependent loss over a wide wave range and provides high diffraction efficiency even with a small groove pitch and high resolving power and dispersion. In a transmission grating 10, multiple parallel ridges 22 that are transparent for the wave range to be used are disposed on one side of a substrate 20 that is transparent for the wave range to be used. Parallel grooves 24 are formed at a fixed pitch a between these ridges. Light is applied from the surface of the transmission grating on which the grooves are formed and diffracted light is extracted from the substrate surface on which grooves are not formed. The groove pitch a is set to a range of 0.51 ?c-1.48 ?c, where ?c is the central wavelength.

Abstract: It is a collimator adapted to convert divergent light beams outputted from an optical fiber bundle to parallel light beams through a collimator lens. A large diameter optical fiber is disposed between an optical fiber bundle, which is a bundle of a large number of multimode optical fibers and serves as one optical transmission path, and a collimator lens. A cross-section of the core of the large diameter optical fiber is larger than a range in which the cores of the optical fibers of the optical fiber bundle are present. Also, a group of divergent light beams outputted from the optical fibers of the optical fiber bundle is converted by the large diameter optical fiber to one light beam.

Abstract: The present invention targets a spectral optical element that outputs a light inputted at a predetermined incident angle to a predetermined direction depending on its wavelength. A spectral optical element according to the present invention includes a transmission diffraction optical element, and an optical phase control element that is fixed and arranged to be opposed to a diffracted light output surface of the transmission diffraction optical element so that the diffracted light is inputted therein. Then, this optical phase control element is constructed so that an optical length with respect to a light passing through the optical phase control element is changed in accordance with change of a diffraction angle of the diffracted light depending on the wavelength.

Abstract: A light measuring device is designed, so that excitation light, emitted by a light source, is guided through an excitation light optical fiber to irradiate a sample, and that fluorescence discharged by the sample is guided to an optical detection system through a receiving light optical fiber. A coupling lens is arranged ahead of the excitation light optical fiber and ahead of the receiving light optical fiber on the sample side. A sample container for retaining a sample is so designed that a lens portion, for collecting excitation light and fluorescence, is integrally formed with the cylindrical bottom. According to this arrangement, excitation light is changed to parallel light or converged light by the coupling lens, and is collected at the sample by the lens portion integrally formed with the bottom of the sample container.

Abstract: It is a collimator adapted to convert divergent light beams outputted from an optical fiber bundle to parallel light beams through a collimator lens. A large diameter optical fiber is disposed between an optical fiber bundle, which is a bundle of a large number of multimode optical fibers and serves as one optical transmission path, and a collimator lens. A cross-section of the core of the large diameter optical fiber is larger than a range in which the cores of the optical fibers of the optical fiber bundle are present. Also, a group of divergent light beams outputted from the optical fibers of the optical fiber bundle is converted by the large diameter optical fiber to one light beam.

Abstract: An optical module according to the invention can achieve an optical system using a transmission-type diffraction grating for bending the optical path of incident light with a specific wavelength by about 90°. A substrate of the transmission-type diffraction grating is mounted at an angle in a range of ±5° with respect to the design incident angle ? of the incident light. The optical system can be applied to a light multiplexing/demultiplexing module.

Abstract: As a feature of a glass substrate having at least one fine hole according to the invention, a side wall surface of the fine hole is connected to each surface of the glass substrate by a curved surface as a boundary portion between the two. As another feature of the glass substrate, a layer denatured by machining is removed from the inner wall surface of the fine hole and the boundary portion between the wall surface and each surface of the glass substrate. The fine hole is produced by: forming a fine hole in a glass substrate by machining or laser machining; and then applying liquid-phase chemical etching to surfaces of the glass substrate and the fine hole. On this occasion, it is desirable that the etching liquid used for the liquid-phase chemical etching is either of an aqueous solution of hydrofluoric acid and an aqueous mixture solution of hydrofluoric acid and ammonium fluoride.

Abstract: A transmission diffraction optical element is presented in which ridges having a roughly rectangular cross-section shape are disposed parallel to each other at a regular pitch at the surface of a substrate. Striped thin-film layers are formed on these ridges and a thin-film layer is inserted between the substrate and the ridges. The thin-film layers are arranged at a regular pitch identical to the regular pitch of the ridges and the thin-film layer does not have a periodic pattern oriented in the same direction as the periodic pattern of the ridges.

Abstract: The present invention targets a spectral optical element that outputs a light inputted at a predetermined incident angle to a predetermined direction depending on its wavelength. A spectral optical element according to the present invention includes a transmission diffraction optical element, and an optical phase control element that is fixed and arranged to be opposed to a diffracted light output surface of the transmission diffraction optical element so that the diffracted light is inputted therein. Then, this optical phase control element is constructed so that an optical length with respect to a light passing through the optical phase control element is changed in accordance with change of a diffraction angle of the diffracted light depending on the wavelength.

Abstract: A transmission grating that provides low polarization dependent loss over a wide wave range and provides high diffraction efficiency even with a small groove pitch and high resolving power and dispersion. In a transmission grating 10, multiple parallel ridges 22 that are transparent for the wave range to be used are disposed on one side of a substrate 20 that is transparent for the wave range to be used. Parallel grooves 24 are formed at a fixed pitch a between these ridges. Light is applied from the surface of the transmission grating on which the grooves are formed and diffracted light is extracted from the substrate surface on which grooves are not formed. The groove pitch a is set to a range of 0.51 ?c-1.48 ?c, where ?c is the central wavelength.

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: 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 ? 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: 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 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.