Abstract: An end face of a plastic optical fiber end is treated so as not to extrude to the core side face when the plastic optical fiber end is softened and fused. The core end face of the plastic optical fiber end is pressed intermittently on a mold that is heated to a certain temperature to soften and fuse the core end face to thereby transfer the transfer face of the mold on the core end face.

Abstract: A metal ring for an optical element that is served to cover a peripheral side surface of a lens and served to fix the lens to a mounting member by means of soldering is provided with a thin-wall sleeve a diameter of which is expanded toward a peripheral direction by means of pressure received from an optical material disposed inside the metal ring to thereby obtain a final peripheral side surface size, a thin-wall portion having an inside periphery near an extension of an inside peripheral surface of the thin-wall sleeve on one of apertures of the thin-wall sleeve, and a holding portion comprising a flange that projects from an edge of the aperture toward the aperture. A metal ring for an optical element, a method for fabrication of the optical element having the metal ring, and an optical element having a metal ring of the invention employ the abovementioned metal ring.

Abstract: A diaphragm structure is provided at an outer edge portion on an incident side of a lens which converges a collimated incident light and outputs the converged light, the diaphragm structure being constructed so that a portion of the collimated incident light is reflected away from or toward an optical axis of the collimated light.

Abstract: A beam-splitting/coupling apparatus comprises first and second frame members which each have a contact surface and a beam guide path. An optical filter is provided between the contact surfaces with the front and rear surfaces of the optical filter held by the first and second frame members respectively. The first and second frame members are held in a case by external flexible forces. A beam propagates from the beam guide path of the first frame member to the beam guide path of the second frame member by way of the optical filter.

Abstract: An optical element includes a lens holder, and an optical lens integrally held by an inner wall portion of the lens holder and having a lens optical surface at an opening in the lens holder in the direction of the optical axis of the optical lens. A projecting portion is formed in the inner wall portion of the holder and adjacent to the opening. An outer peripheral edge surface is placed of the lens optical surface is placed under the projecting portion and is pressed in contact with the projecting portion over the entire periphery.

Abstract: An optical fiber connector including a receptacle housing and a cylindrical member disposed within the receptacle housing, with fine pores for taking dust therein being formed in an inner wall of the cylindrical member, wherein a ferrule provided at a tip end of an optical fiber is inserted into the cylindrical member, allowing dust which has entered the cylindrical member to be received within the fine pores, an outer periphery of the ferrule is brought into abutment against the inner wall of the cylindrical member, and the tip end of the optical fiber is attached to the receptacle housing.

Abstract: An optical semiconductor device to increase optical communication speed has a silicon substrate with an etched V-shaped first groove portion, a light emitting element which has an optical axis in the direction of the first groove portion and is mounted to the upper surface of the silicon substrate, and a high NA aspheric lens is mounted in the first groove portion. The first groove portion is composed of first and second opposing inclined surfaces and a third inclined surface perpendicular to the first and second inclined surfaces. A slit is cut in the silicon substrate extends in a direction perpendicular to the direction of the first groove portion and includes the first, second, and third inclined surfaces. The aspheric lens is mounted to the first and second inclined surfaces and has a part thereof protruding in the slit.

Abstract: The optical communication system comprises at least one transmitter provided with a light source for emitting white light having a wide wavelength band, an optical fiber for transmitting white light emitted from the light source and at least one optical switch placed along the optical fiber, and at least one receiver. The optical switch has an optical filter for selectively splitting predetermined different wavelengths and reflecting other wavelengths, and a switching device for cutting off or passing lights of the wavelengths split by the optical filter. An optical filter merges light transmitted by the switching device with lights of other wavelengths reflected by the optical filter and transmits it to the optical fiber.

Abstract: An optical fiber connector includes a receptacle casing, a cylinder provided in the receptacle casing, and a wire spring disposed on the inner wall of the cylinder. In the optical fiber connector, a fiber holding part provided at an end of an optical fiber is inserted into the cylinder, the outer periphery of the fiber holding part is elastically pressed by the wire spring in the direction perpendicular to an optical axis of the optical fiber, the outer periphery of the fiber holding part is brought into abutment with the inner wall of the cylinder, and the end of the optical fiber is fitted to the receptacle casing.

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.

Abstract: An optical transmission/reception module in which an LD, a lens holder, which supports a lens, a partial wave filter, a lens holder, which supports a lens, and an optical fiber are all mounted to a housing block, coaxially along a first axis. A reflecting mirror, a lens holder, which supports a lens, and a PD are also mounted to the housing block, coaxially along a second axis which is parallel to the first axis. Cutouts are formed in the housing block for providing large openings forwardly of and perpendicular to a mounting surface for mounting the partial wave filter thereon and a mounting surface for mounting the reflecting mirror thereon. In such an optical transmission/reception module, it is possible to maintain the precision with which a partial wave filter, which passes a transmission light therethrough, and a reflecting member, which reflects a reception light, are mounted to a desired mounting angle at a high level, and to reduce assembly costs.

Abstract: A dielectric multilayer film which has a bandpass characteristic in which a light beam having a wavelength .lambda.2 passes and a light beam having any of the other wavelengths is blocked is formed on the emergent-side surface of a lens provided near a light-receiving device which receives a light beam having the wavelength .lambda.2. A dielectric multilayer film which has a bandpass characteristic in which a light beam having a wavelength .lambda.1 passes and a light beam having any of the other wavelengths is blocked is formed on the emergent-side surface of a lens provided near another light-receiving device which receives a light beam having the wavelength .lambda.1.

Abstract: An optical coupler including optical fibers having gaps between first coverings and second coverings corresponding thereto. Each cladding of the two optical fibers is formed into a proper shape, with a taper of a proper thickness. The two optical fibers are then joined together, forming a joined portion which engages an engaging groove in a pair of blocks and the pair of blocks are affixed together by welding. Thereafter, the second coverings are affixed to cutouts in a retainer member. Lastly, the retainer, fitted to the blocks, is affixed thereto. Such an optical coupler is highly practical, does not allow deterioration of light dividing properties caused by changes in the length of the cladding joined portion as a result of an external stress, and prevents breakage of the joined portion.

Abstract: A method for manufacturing a lens with a lens barrel having a stopper by forming a uniform optical function coating on both lens surfaces. The method includes the steps of forming a first optical function coating on one side of a lens material, then inserting the lens material into a lens barrel so that the surface coated with the first optical function coating will face the long barrel side of the lens barrel, press molding lens surfaces by heating the lens material over its softening point, and finally forming a second optical function coating on the lens surface facing the short barrel side of the lens barrel.

Abstract: A lens fixing structure obviates the need for using a U-shaped lens holder retaining member which is apt to cause incomplete laser welding and which adds to cost. According to the lens fixing structure, a lens is fixed as follows: firstly, only a lens holder is held by a retainer to position it in directions x, y, and z while it is being suspended with respect to a base; secondly, a pair of lens holder retaining members composed of magnet are attracted to the lens holder while they are placed on the base by another retainer or by hands; thirdly, another retainer or other retaining element is removed from the lens holder retaining members; and lastly, the lens holder retaining members and the base are fixed at predetermined points by laser welding and the lens holder retaining members and the lens holder are also fixed at other predetermined points by laser welding.

Abstract: An optical fiber connector designed so as to reduce the number of assembly steps and the number of component parts to reduce the manufacturing cost while maintaining improved characteristics under certain environmental conditions. The optical fiber connector has a sleeve fitted to a ferrule of a plug, a clamper engaged with the plug to hold the same, and a housing in which the clamper is held. The clamper is formed of a synthetic resin and has elastically-deformable leg portions and engaging portions. Engaging projections 16g to be engaged with the engaging portions of the clamper to hold the clamper in the housing are provided in the housing.

Abstract: A module for optical communication, adapted to prevent light from being reflected on the end surface of an optical fiber when a ferrule is inserted therein, and to increase the precision with which the positioning of an end surface of the optical fiber is performed. In the module, the circumference of an anti-reflection transparent film is held in a groove of a stopper member and is pressed against the inner circumference of an elastic sleeve. When the ferrule is inserted in the sleeve, the film adheres to the end surfaces of the optical fiber and the ferrule closely and securely. Thus, no air layer is formed between the film and the end surface of the optical fiber. Laser light is not reflected on the end surface of the optical fiber. The end surface of the ferrule adheres closely to a positioning face of the stopper member, though the film intervenes therebetween.