Abstract: An optical shutter including a multi-layer fixed filter and a multi-layer movable filter arranged with a gap therebetween controls the transmittance of light passing through the multi-layer filters. The optical shutter includes minute driving elements provided on the movable filter. Operating the minute driving elements varies a distance of the gap defined between the fixed filter and the movable filter. Operation of the movable filter is restricted by a stopper that comes into contact with the movable filter when the gap has the maximum distance and by a bump formed on the fixed filter. The minute driving elements are joined to the movable filter with elastic bonding layers therebetween.

Abstract: An optical head comprises an integrated unit for recording and reproducing page data on a reflective recording medium, wherein the integrated unit includes recording and reproducing units each corresponding to a bit of data of the page data, wherein each of the recording and reproducing units has a light emitter for emitting an object beam and a reference beam, an optical switch for transmitting or blocking the object beam, and a detector. Each of the recording and reproducing units records a bit of data corresponding to a state indicating whether or not a hologram has been formed and reproduces a bit of data corresponding to a state indicating whether or not a reference beam has been received by the light receiver when a reference beam is emitted to a recording position. The integrated unit of the optical head records and reproduces page data on a recording medium by recording and reproducing bit data on the recording medium by each of the recording and reproducing units.

Abstract: A holographic memory device includes a laser oscillator for emitting multimode laser light to be incident on a holographic storage medium. The laser light of a main mode has a half-width such that the wavelength distribution of the main mode is continuous with the wavelength distributions of the two adjacent side modes and such that the laser light has a continuous wavelength distribution over the main mode and all the side modes.

Abstract: A high-precision positioning apparatus includes a fine driving unit for producing horizontal and small movements of a flat recording medium relative to an optical system, the medium being used for optically recording and reproducing information. The fine driving unit includes a frame-shaped unit body, a first driving frame inside the unit body, and a second driving frame inside the first driving frame and secured at a position adjacent to a magnetized portion of the recording medium. The first driving frame is movable relative to the unit body by fine driving devices in the horizontal direction of the recording medium, while the second driving frame is movable relative to the first driving frame by other fine driving devices in the horizontal direction of the recording medium and in the direction substantially orthogonal to the moving direction of the first driving frame, thereby producing horizontal and small movements of the recording medium.

Abstract: An optical head comprises an integrated unit for recording and reproducing page data on a reflective recording medium, wherein the integrated unit includes recording and reproducing units each corresponding to a bit of data of the page data, wherein each of the recording and reproducing units has a light emitter for emitting an object beam and a reference beam, an optical switch for transmitting or blocking the object beam, and a detector. Each of the recording and reproducing units records a bit of data corresponding to a state indicating whether or not a hologram has been formed and reproduces a bit of data corresponding to a state indicating whether or not a reference beam has been received by the light receiver when a reference beam is emitted to a recording position. The integrated unit of the optical head records and reproduces page data on a recording medium by recording and reproducing bit data on the recording medium by each of the recording and reproducing units.

Abstract: There is disclosed a high precision positioning apparatus capable of realizing accurate positioning of a recording medium with respect to an optical system by minute movement at a relatively low cost. The high precision positioning apparatus comprises a driving unit 1 for minutely moving a flat-plate shaped recording medium 10, which records/reproduces information using light, with respect to an optical system in an in-plane direction of the recording medium 10. The driving unit 1 comprises a frame-shaped unit body 2, a first drive frame 3 accommodated inside the unit body 2, and a second drive frame 4 accommodated inside the first drive frame 3 and fixed in the vicinity of a recording portion 11 of the recording medium 10.

Abstract: An optical shutter including a multi-layer fixed filter and a multi-layer movable filter arranged with a gap therebetween controls the transmittance of light passing through the multi-layer filters. The optical shutter includes minute driving elements provided on the movable filter. Operating the minute driving elements varies a distance of the gap defined between the fixed filter and the movable filter. Operation of the movable filter is restricted by a stopper that comes into contact with the movable filter when the gap has the maximum distance and by a bump formed on the fixed filter. The minute driving elements are joined to the movable filter with elastic bonding layers therebetween.

Abstract: An apparatus for depositing an optical thin film at a high accuracy has a vacuum chamber in which a thin film is formed on a substrate by vapor deposition of a material at a target using ion beams from an ion gun, an optical monitor for optically measuring the thickness of the thin film and outputting transmittance data DT, a crystal monitor for measuring a frequency which changes as the deposition proceeds and for outputting frequency data DF, and a determination circuit 12. The determination circuit select between the optical monitor and the crystal monitor to control the thickness of the thin film to be formed on the substrate.

Abstract: A functional multilayer film and a method for manufacturing the same is provided wherein the intervals of fine metallic bodies in the thickness direction of film and the arrangement thereof in the surface direction of film are regular, and the fine metallic bodies arranged on each layer in the surface direction of film are aligned in the thickness direction of film.

Abstract: A plurality of composite target materials containing a plurality of metal elements and oxygen, wherein the mix ratio of the metal elements is different individually for each of the target materials, are disposed in a chamber of a sputtering apparatus. The targets are sputtered one by one successively by use of a common ion gun to thereby form successively a laminate film comprising uniform films having a precise film thickness on a surface of a substrate so that the refractive index of the laminate film changes stepwise.

Abstract: A method of producing multilayered optical filters by using a genetic algorithm that determines an optimal combination of refractive indexes and thicknesses for each layer of the filter is described. The method generates initial values for the component and places the values within a matrix P, where P=(X1, X2, X3, . . . , Xi, . . . , Xs) and Xi is an elementary matrix that includes the refractive index and thickness of each layer i. The method may generate mutated patterns by increasing or decreasing the thicknesses and refractive indexes of the initial pattern. It may also perform a cross-over process, selecting patterns from grouping of mutated patterns. Alternately, the method may perform a process where selected patterns having optical characteristics closest to the desired characteristics from the initial, mutated or crossover patters are chosen. The genetic algorithm utilizing the above processes repeats until the optical characteristics fall within the desired range.

Abstract: An apparatus for depositing an optical thin film at a high accuracy has a vacuum chamber in which a thin film is formed on a substrate by vapor deposition of a material at a target using ion beams from an ion gun, an optical monitor for optically measuring the thickness of the thin film and outputting transmittance data DT, a crystal monitor for measuring a frequency which changes as the deposition proceeds and for outputting frequency data DF, and a determination circuit 12. The determination circuit select between the optical monitor and the crystal monitor to control the thickness of the thin film to be formed on the substrate.

Abstract: By stacking films whose refractive index differs, there is formed an optical filter which reflects light in a predetermined wavelength band for separation. The films whose refractive index differs are stacked by varying the film thickness. As a result, there is formed a filter comprising a low refractive index region having a physical thickness of dL and an equivalent refractive index of nL* and a high refractive index region having the physical thickness of dH and the equivalent refractive index of nH* alternately stacked. The equivalent optical film thicknesses are set to 1/(4·&lgr;0) or 1/(2·&lgr;0), whereby it is possible to reflect light having a narrow band of wavelengths with a wavelength &lgr;0 being centered for separation.

Abstract: Disclosed herein is an optical communication device. Branching filters are placed on a trunk fiber along which light signals of wavelengths &lgr;3, &lgr;4 and &lgr;5 are transmitted in multiplexed form. A transmitting-side branch fiber and a receiving-side branch fiber are respectively placed on the opposite sides of the branching filters. The branching filters both have spectral characteristics in which they reflect the proximity of wavelengths &lgr;1 and &lgr;2 and pass the wavelengths &lgr;3, &lgr;4 and &lgr;5. A white light source is provided at a termination of the transmitting-side branch fiber and light switches are disposed in the course thereof. The light switches incorporate therein branching filters placed on the optical path when they are turned on and withdrawn from the optical path when they are turned off.

Abstract: A plurality of composite target materials containing a plurality of metal elements and oxygen, wherein the mix ratio of the metal elements is different individually for each of the target materials, are disposed in a chamber of a sputtering apparatus. The targets are sputtered one by one successively by use of a common ion gun to thereby form successively a laminate film comprising uniform films having a precise film thickness on a surface of a substrate so that the refractive index of the laminate film changes stepwise.

Abstract: The optical fiber connector of the invention includes two optical fibers facing to each other, in which one optical fiber of the two has a spherical end face, when the core diameter of the optical fiber having the spherical face is given by E1, the numerical aperture thereof by NA1, the refractive index by n1, the radius of curvature of the spherical face by r, the core diameter of the other optical fiber by E2, the distance between the two optical fibers by L, the focal length f of the optical fiber is expressed by f=r/(n1−1). Further, when the beam diameter on the end face of the optical fiber is given by Es, the beam diameter Es=2·L·tan(sin−1·NA1) is deduced, and the connection efficiency &eegr; of the two optical fibers satisfies the following inequality: E2/(E1+Es)<&eegr;<(E2/(Es+(L/f−1)·E1))2≦1.0, in the focal length f≦L; or E2/(E1+Es)<&eegr;<(E2/(Es+(1−L/f)·E1))2≦1.

Abstract: In an optical transmitting and receiving module, a transmitting light beam having a wavelength &lgr;1 emitted from an light-emitting device passes through an optical demultiplexing filter and enters an optical fiber, and a receiving light beam emitted from an end face of the optical fiber is reflected from the optical demultiplexing filter and is incident on a light-receiving device. A cover for covering the front space of the optical demultiplexing filter is placed on a casing block, and a tongue piece serving as a returning-light preventing unit is formed on the cover. When a transmitting light beam emitted from the light-emitting device is reflected from the optical demultiplexing filter, the direction in which the reflected light advances is changed by the tongue piece so that the reflected light is not incident on the light-receiving device.

Abstract: Disclosed herein is an optical communication connector. A connector optically couples between a pair of plastic fibers and a pair of silica fibers, and a connector optically couples between the other ends of the silica fibers and a pair of plastic fibers. In such a construction, signal light is bidirectionally transmitted using these fibers. The connector is provided with one condenser lens within a casing. On the side of the transmission of signal light from the silica fiber to the plastic fiber, end surfaces of both cores P and Q are brought into intimate contact with each other. On the side of the transmission of signal light from the plastic fiber to the silica fiber, end surfaces of both cores P and Q are opposed to each other with the condenser lens interposed therebetween. The other connector is also constructed in a manner similar to the above connector.

Abstract: Output drop due to misalignment of the mounting positions of optical fibers between the optical axis direction of laser light and a direction perpendicular to the optical axis direction is prevented. A light guide part 100a of an optical fiber 100 is engaged in a predetermined through hole 19 provided in a bottom wall 18 of a case 11, the light guide part 100a being uncovered by stripping a protective jacket 100b from the tip 100c of the optical fiber 100, whereby an optical filter 30 disposed at a predetermined interval on an extension of the core 100z of the optical fiber 100 and the optical fiber 100 are positioned.

Abstract: An insertion hole for inserting an optical fiber is formed at a case, and then a resilient leaf spring and an operating button are stored in the case. The leaf spring is comprised of a through-pass hole formed at the central part of the leaf spring in correspondence with the insertion hole, a plurality of resilient lock claws extended from the circumferential edge of the through-pass hole toward the center thereof, and a groove recessed from a part of the circumferential edge in an outward direction. The operating button is provided with a stem of which part can be fed into or out of the case, the stem abutted against both edges of the groove is pushed under an operation of the stem, thereby a held state of the lock claws against the optical fiber can be released indirectly.