Abstract: A filter module comprising a lens, three optical fibers, an optical filter, and a mirror, wherein the three optical fibers are arranged a single side of the lens.

Abstract: An optical fiber collimator using a gradient index rod lens for securing a required long opposing distance and easy handling. The collimator includes a single mode fiber and a gradient index rod lens for receiving an incident light from the single mode fiber and converting the incident light into a collimated light, or condensing an incident light and coupling the condensed incident light to the single mode fiber. A meandering period (pitch) of a ray determined by a refractive index distribution of the rod lens is decided. The gradient index rod lens has a lens length larger by 0.5 meandering periods than a minimum lens length required to obtain a predetermined opposing distance between a pair of the rod lenses.

Abstract: A method of producing a collimator or collimator array is constituted by the steps of: fixing long-size gradient index rod lens raw materials on a substrate having end surfaces each forming a plane so that the long-size gradient index rod lens raw materials are arranged side by side at intervals of the predetermined pitch while optical axes of the gradient index rod lens raw materials are parallel to one of the end surfaces of the substrate; cutting the substrate provided with the gradient index rod lens raw materials at a predetermined position in a plane perpendicular to the optical axes of the gradient index rod lens raw materials to thereby divide the substrate provided with the gradient index rod lens raw materials into lens array parts; adjusting the divided lens array parts so that each of the gradient index rod lens raw materials in the lens array parts has a defined lens length; and arranging the lens array parts so that the cut end surfaces of the lens array parts are made to face each other while o

Abstract: An aligning tool having a plurality of grooves formed side by side is provided; gradient index rod lenses are placed in alignment within the grooves at an average spacing of 1 &mgr;m-5 &mgr;m; the gradient index rod lenses are fixed to form an integral unit as they maintain the aligned state; thereafter the end faces of each rod lens are polished.

Abstract: A filter module includes a first optical fiber collimator, a second optical fiber collimator, and a filter located between the first and second optical fiber collimators. The first optical fiber collimator includes a first optical fiber, a first optical fiber chip for holding the first optical fiber, and a first lens. The second optical fiber collimator includes second optical fibers, a second optical fiber chip for holding the second optical fiber, and a second lens. The filter is located between and coaxial with the first and second lenses. The filter, the first lens, and the second lens form a center piece of the filter module.

Abstract: A rod lens array has a construction in which a number of rod-shaped lens elements are arrayed in at least one row between two side plates, and the clearances are filled with resin to form a single integral unit. Two side plates are formed of glass plates, the surfaces of these two glass plates facing the lens elements are flat and smooth, the outer surfaces on the opposite sides are formed with reflection-preventing portions, the side surfaces of both of the glass plates on the beam-exit side are formed with beam-shielding zones from the outer edges inwardly along almost the whole length. The width of the light-tight zone Ts satisfies the relation; Tg>Ts>Tg−Z×D×{2+{square root over (3)}×(n−1)}/{2×(TC−Z)}, where Tg is a thickness of the glass plate, D is a diameter of lens element, Z is a length of lens element, TC is a conjugate length, and n: number of columns of lens element.

Abstract: An optical fiber collimator which facilitates optical adjustment. The optical fiber collimator includes a gradient index rod lens, and an optical fiber optically connected to the rod lens. An anti-reflection film is formed on one end face of the rod lens. The anti-reflection film has a refractive index which continuously changes from a value substantially equal to that of a center refractive index of the rod lens to a value substantially equal to that of the refractive index of the optical fiber along a film thickness direction of the anti-reflection film. A refractive index matching medium having a refractive index substantially equal to that of the optical fiber bonds the anti-reflection film to the end face of the optical fiber.

Abstract: An optical module which satisfies a required insertion loss and can be easily assembled with high productivity. The optical module includes first optical fiber, a first lens, an optical device, a second lens, and second optical fiber. The first lens receives an incident light from the first optical fiber and converts the incident light into a parallel light. The optical device receives the parallel light and performs predetermined optical processing on the parallel light. The second lens receives a transmitted parallel light from the optical device and converge the transmitted parallel light to produce an outgoing light. The second optical fiber receives the outgoing light. An optical axis of the first lens and an optical axis of the second lens are substantially coincident with each other. An optical axis of the first optical fiber and an optical axis of the second optical fiber are substantially parallel with each other and substantially parallel to the optical axes of the first and the second lenses.

Abstract: A method of aligning a fiber collimator in a short time. Light emitted from a collimator is reflected by a mirror. Reflected light passes through the collimator, and is measured by a light intensity measuring device. Rotating bodies rotatably support the mirror about an X-axis and a Y-axis orthogonal to the optical axis. An aligner simultaneously drives the rotating bodies to scan an optimal angle for the mirror. With the mirror fixed at the optimal angle, the distance between a collimation lens of the collimator and the optical fiber is changed. Subsequently, the optimal angle of the mirror is again scanned.

Abstract: An optical fiber collimator having a lens (10), and an optical fiber chip (14) disposed at a distance from the lens, the optical fiber chip holding an end portion of an optical fiber (12) and having an end surface treated to be inclined. The optical axis of the optical fiber is made eccentric with respect to the center of the lens to set the eccentric quantity of the optical fiber so that the center of the lens substantially coincides with the center of a light beam incident on the lens. The kind of the lens is optional. The lens may be an inexpensive spherical lens or may be a gradient index rod lens. When a gradient index rod lens is used, a lens in which a surface facing to the optical fiber chip is treated to be inclined is used as the gradient index rod lens.

Abstract: An aligning tool having a plurality of grooves formed side by side is provided; gradient index rod lenses are placed in alignment within the grooves at an average spacing of 1 &mgr;m-5 &mgr;m; the gradient index rod lenses are fixed to form an integral unit as they maintain the aligned state; thereafter the end faces of each rod lens are polished.

Abstract: A method of producing a collimator or collimator array is constituted by the steps of: fixing long-size gradient index rod lens raw materials on a substrate having end surfaces each forming a plane so that the long-size gradient index rod lens raw materials are arranged side by side at intervals of the predetermined pitch while optical axes of the gradient index rod lens raw materials are parallel to one of the end surfaces of the substrate cutting the substrate provided with the gradient index rod lens raw materials at a predetermined position in a plane perpendicular to the optical axes of the gradient index rod lens raw materials to thereby divide the substrate provided with the gradient index rod lens raw materials into lens array parts; adjusting the divided lens array parts so that each of the gradient index rod lens raw materials in the lens array parts has a defined lens length; and arranging the lens array parts so that the cut end surfaces of the lens array parts are made to face each other while op

Abstract: A rod lens array has a construction in which a number of rod-shaped lens elements are arrayed in at least one row between two side plates, and the clearances are filled with resin to form a single integral unit. Two side plates are formed of glass plates, the surfaces of these two glass plates facing the lens elements are flat and smooth, the outer surfaces on the opposite sides are formed with reflection-preventing portions, the side surfaces of both of the glass plates on the beam-exit side are formed with beam-shielding zones from the outer edges inwardly along almost the whole length.

Abstract: A method for improving the characteristics of fused slag material is disclosed. This improved method results in a fused slag having resistance against pulverization at the cooling process or generation of yellowish turbid water due to contact of slag lumps with rain water, this method characterized by forming a slag treatment material by rough crushing a substantially dehydrated heat-treated material containing boron, and adding that slag treatment material to molten slag.

Abstract: An optical fiber element includes a non-armored optical glass fiber element having a numerical aperture of 0.35 or more, and a resin layer obtaining by applying a resin composition to a surface of the non-armored optical glass fiber element in contact therewith and by curing the resin composition, the cured resin layer essentially consisting of the resin composition having a Shore D hardness value of 65 or more defined in the Japanese Industrial Standards (JIS) at room temperature.

Abstract: A steel slag or iron slag which is a by-product generated at the time of steel or iron metallurgy and a method of manufacturing the same are disclosed. This slag is characterized in that it contains at least 0.15 wt % of boron component in the form of B.sub.2 O.sub.3 and has resistance against degradation in the fused slag cooling-down process and against generation of yellowish turbid water at the time of contact of slag with rain water.

Abstract: A method for improving the characteristics of fused slag material is disclosed. This improved method results in a fused slag having resistance against pulverization at the cooling process for generation of yellowish turbid water due to contact of slag lumps with rain water, this method characterized by forming a slag treatment material by rough crushing a substantially dehydrated heat-treated material containing boron, and adding that slag treatment material to molten slag.