Abstract: An optical fiber interface for coupling input light power from a light source to an optical fiber. The optical fiber has an optical axis, an incident end face extending transverse to the optical axis, a core region having a predetermined diameter, and a clad region surrounding the core region. The end face comprises a first surface portion having the shape of an element of a sphere. The sphere has a center on the optical axis and a diameter not greater than the diameter of the core region. The first surface portion of the end face is symmetrical with respect to the optical axis and extends from the optical axis along the core region toward the clad region. The end face also comprises a second surface portion having the shape of an element of a cone extending from the first surface portion of the end face along the clad region, the second surface portion being tangential to the first surface portion of the end face.

Abstract: A light coupling device for coupling a light source to an optical fiber. The device includes a first cylindrical sleeve carrying a GRIN lens and a ferrule. The ferrule receives the optical fiber. Movability of the ferrule along the optical axis of a first through-hole in the first sleeve allows a determination of a focal length between the GRIN lens and an incident end face of the optical fiber. A first setting means sets a relative position of the ferrule with respect to the first sleeve for holding the two in position with respect to one another when the GRIN lens and the incident end face of the optical fiber are separated by a distance equal to the focal length therebetween. The device further includes a second cylindrical sleeve. The first sleeve is coaxially disposed within a second through-hole of the second sleeve, and a light source unit is concentrically disposed within the second through-hole.

Abstract: An optical fiber end-surface polishing device has an improved ferrule fixing device allowing ferrules with optical fibers to be attached to or detached from a holder plate for polishing by a simple operation. The optical fiber end-surface polishing device, having a ferrule fixing device, simultaneously polishes the end surfaces of a plurality of ferrules with optical fibers fixed to and supported by a holder plate. The device includes ferrule accommodating sockets provided on the holder plate and having through holes for accommodating ferrules; and ferrule presser levers supported by stationary shafts substantially parallel to the through holes and biased toward descent by biasing devices, wherein each of the ferrule presser levers is movable between an angular position where the ferrules inserted into the associated ferrule accommodating sockets are downwardly pressed and an angular position where the polished ferrules can be detached.

Abstract: To produce base boards each usable for an information recording medium such as a photoelectromagnetic disc or the like by employing an injection molding process, an injection molding die of the type comprising a die half on the stationary side and a die half on the movable side includes a cylindrical supporting member on the stationary side, a die assembly on the stationary side arranged in the cylindrical supporting member, a cylindrical supporting member on the movable side, a die assembly on the movable side arranged in the cylindrical supporting member, a cylindrical guide member located between both the cylindrical members, a first driving unit for displacing the die half on the movable side, and a second driving unit for actuating an ejector sleeve.

Abstract: To injection-mold a base board for an optical disc or the like, an injection molding die includes a stamper plate attaching/detaching device installed therein. The stamper attaching/detaching device includes as essential components a stamper plate attaching/detaching bush adapted to be fitted into a tapered bush fitting hole formed in a die half on the movable side together with a stamper plate to be firmly placed on a die cavity, an actuating rod having a pinion gear formed at the fore end part thereof to mesh with a rack formed at the lower end part of the stamper plate attaching/detaching bush, and a lock nut for immovably hold the actuating rod during a series of molding operations. The stamper plate is removably fitted around the outer periphery of a flange portion of the stamper plate attaching/detaching bush.

Abstract: An optical demultiplexing/multiplexing device made with a few stable components by easy fabrication processes, which provides a flat response over the specified frequency range.

Abstract: An injection molding die for simultaneously molding a plurality of optical disc base boards. The die has a stationary die assembly portion that includes a first base plate having a first center axis, and a plurality of first cavities each having a respective center axis. The first cavities are arranged in an equally spaced relationship along a circumference of a circle coaxial with the first center axis. The die also has a movable die assembly portion that includes a second base plate having a second center axis, and a plurality of second cavities each having a respective center axis. Each second cavity positionally corresponds to a respective first cavity. The first center axis is aligned with the second center axis using a guide rod fixedly secured to the first base plate and that extends along the first center axis, and by using a guide member that extends along the second center axis to be positionally coincident with the first center axis.

Abstract: An apparatus for grinding end surfaces of ferrules together with optical fibers each firmly received therein includes as essential components a platform serving as a base for the apparatus, a grinding board assembly rotationally driven such that a grinding board is displaced along a horizontal reference plane as it is rotated, a ferrule holder for holding the ferrules each of whose foremost end to be ground is oriented toward the grinding board, a ferrule holder supporting member for bringing the ferrule holder to a surface position to be assumed by the ferrule holder on completion of a grinding operation while supporting the ferrule holder, and a thrusting unit for normally thrusting the ferrule holder toward the grinding board. It is desirable that the center of the grinding board assembly be positionally offset from the center of the ferrule holder supporting member.

Abstract: To connect one ribbon-shaped optical fiber cord to an opponent ribbon-shaped optical fiber cord while making reliable optical connection therebetween, an optical fiber splicer is used. The optical fiber splicer includes as essential components an aligning member and a cover member, and the cover member is fitted into the aligning member to build an integral structure without an optical fiber using an adhesive. In practical use, after the adhesive is hardened, both the ribbon-shaped optical fiber cords are inserted into the integral structure from both sides of the optical fiber splicer so that sheathless optical fibers of both ribbon-shaped optical fiber cords are firmly received in V-shaped aligning grooves on the aligning member in a face to-face relationship.

Abstract: An optical fiber termination device wherein temperature rise is minimized when light power is high or a power laser is used therewith. A first optical fiber is connected to a second optical fiber by fusing the core of the first optical fiber to the clad of the second optical fiber with a discharge generated between electrodes. The first optical fiber is inserted into a hole at the center of a ferrule and then the first optical fiber is fastened to the ferrule by fusing them. Thereafter, the edge surface of the ferrule is finished by polishing it. The second optical fiber is covered with a protective cover. Light coming from the core of the first optical fiber is incident on and scattered into the clad of the optical fiber. The light reflected toward the light source is greatly decreased by this structure.

Abstract: An optical attenuator comprising an optical fiber and at least a light attenuating portion disposed on the optical fiber. The light attenuating portion is formed such that a part of the optical fiber is heated by an opposing pair of discharge electrodes or gas burners and then compressed in the axial direction to provide a spherically contoured light attenuating portion or pulled in the axial direction to provide a light attenuating portion having a reduced diameter. In addition, a method and an apparatus for producing an optical fiber of the foregoing type are disclosed. The method is practiced by way of the steps of heating a part of an optical fiber and then physically deforming the heated part to serve as a light attenuating portion by compressing or pulling it in the axial direction.

Abstract: Two types of structural elements each employable for a light diverging/converging device are disclosed. One is a double circuit diverging ferrule which comprises a first semicylindrical ferrule element, a second semicylindrical ferrule element and a cylindrical bushing through which both the ferrule elements are press-fitted. The other is a single circuit converging ferrule which comprises a first semicylindrical ferrule element, a second solid semicylindrical ferrule and a cylindrical bushing through which both the ferrule elements are press-fitted. Three types of light diverging/converging devices, i.e., a diverging ratio variable type 1.times.2 circuit light diverging/converging device, a diverging ratio variable type 2.times.2 circuit light diverging/converging device and a 1.times.2 circuit light diverging/converging device having a constant diverging ratio each of which is constructed by using the aforementioned structural elements are also disclosed. A 2.times.

Abstract: A light attenuating element comprising a ferrule and two optical fibers inserted through the ferrule along an optical axis thereof is disclosed. The inner ends of both the optical fibers are cut with a predetermined inclination angle and spaced from each other with a predetermined distance therebetween to obtain a required light attenuation value. A light attenuating element including an alignment sleeve into which two ferrules each having an optical fiber inserted therethrough are fitted with a predetermined distance being maintained between the foremost ends thereof is also disclosed.

Abstract: A method of grinding ferrules for ribbon type optical fibers wherein the method comprises the steps of locating the end surfaces of the ferrules with respect to a grinding surface of a grinding member, reciprocatingly turnably displacing the ferrules along an arched locus, and grinding the end surfaces of the ferrules with the grinding wheel. To practice the method, an apparatus including a ferrule holding member, a supporting member having the ferrule holding member turnably supported thereon, a driving unit in form of an electric motor including a reduction gear, a connecting rod bridged between the driving unit and the ferrule holding member to reciprocably turn the ferrule holding member, a grinding member mounted on a frame of the apparatus, a grinding position adjusting unit, a compression spring for normally biasing the supporting member in the upward direction, and a base board mounted on the frame of the apparatus for turning the supporting member about an intermediate position thereof.

Abstract: On an optical connector plug main body 3 whose transverse section is a trapezoid, a groove 6 of rectangular transverse section is provided, at a bottom of which a plurality of alignment V grooves 7 are formed. In a plate member 9 of rectangular transverse section has a receiving groove 10 of also rectangular transverse section, the groove 10 being connected with the bottom of the plate member 9. An alignment sleeve 12 has an alignment groove 14 of wedge head shape. The plate member 9 is engaged with the groove 6 of the connector plug main body 3, and protrusions 11 of the plate member 9 is ultrasonic bonded into recesses 8 provided in the connector plug main body 3. A ribbon type optical fiber to which an adhesive is applied is inserted from the groove 6 to complete the connector plug. Thus assembled connector plugs are inserted in the state whose ends are faced with each other into the groove 14 of the alignment sleeve 12 to make the connection of the ribbon type optical fiber.

Abstract: A method of grinding ferrules for ribbon type optical fibers wherein the method comprises the steps of locating the end surfaces of the ferrules with respect to a grinding surface of a grinding member, reciprocatingly turnably displacing the ferrules along an arched locus, and grinding the end surfaces of the ferrules with the grinding wheel. To practice the method, an apparatus including a ferrule holding member, a supporting member having the ferrule holding member turnably supported thereon, a driving unit in the form of an electric motor including a reduction gear, a connecting rod bridged between the driving unit and the ferrule holding member to reciprocably turn the ferrule holding member, a grinding member mounted on a frame of the apparatus, a grinding position adjusting unit, a compression spring for normally biasing the supporting member in the upward direction, and a base board mounted on the frame of the apparatus for turning the supporting member about an intermediate position thereof.

Abstract: A method and an apparatus for grinding the foremost end surface of a ferrule integrated with an optical fiber wherein the foremost end surface of the ferrule is stepwise ground together with the optical fiber to exhibit a predetermined radius of curvature. The grinding process is practiced by way of three steps, i.e., a rough grinding step, a medium grinding step and a finish grinding step. A base board and abrasive grains on an abrasive film required for the medium grinding step have a hardness higher than that of those for the rough grinding step, and a base board and abrasive grains on an abrasive film required for the finish grinding step have a hardness higher than that of those for the medium grinding step. The foremost end surface of the ferrule is projected downward of the lower surface of a holder by a predetermined quantity before the rough grinding step is started.

Abstract: An optical connector ferrule comprising a ferrule base and a cylindrical tip. The ferrule base has a planar end portion extending transverse to the longitudinal axis of the ferrule, and the cylindrical tip has an outside diameter which is less than the outside dimension of the planar end portion of the ferrule base. A first planar end portion of the cylindrical tip extends in a direction transverse to the longitudinal axis, and a second end portion thereof extends at an oblique angle to the longitudinal axis. The surface of the second end portion has a hemispherical shape. The cylindrical tip receives an optical fiber having an end which has a hemispherical shape, and the hemispherical shaped end of the optical fiber is continuous with the hemispherical surface of the second end portion of the cylindrical tip.

Abstract: A new type of optical power attenuator of the variable attenuation type. The optical connector ferrule edges are finished by polishing them at an inclination angle of seven to 12 degrees with respect to the optical axis thereof, and both ferrule edges face each other with a gap therebetween. One of the ferrule edges is fastened not so that it can be rotated whereas the other can be rotated around its optical axis. The attenuation is determined by both the inclination and gap, and it can be set stably by adjustment of the angle of the rotation around the optical axis of the ferrules.

Abstract: A variable light attenuator for use with multiple-fiber ribbons consisting of optical fiber elements. The attenuator consists of movable and fixed ferrule assemblies, each of which is fabricated by inserting a plurality of optical fiber elements arranged in line with equal pitch into a plurality of through holes arranged in line with equal pitch in a block of the substrate, and by polishing the end of the substrate together with the ends of the plurality of optical fiber elements so that the ends are finished to be eight degrees or more inclined with respect to a plane perpendicular to the optical axis of the movable and fixed ferrule assemblies.