Abstract: The present invention provides an optical fiber suitable for the manufacture of optical fiber couplers and having low macrobending loss, low cutoff wavelength, low attenuation, and low sensitivity to variations in overclad mass. One aspect of the present invention provides an optical fiber having a core having an index profile, the index profile of the core having a value of ? of between about 1.7 and about 3.0; and a cladding region surrounding and in contact with the core, the cladding region having an outer radius of at least about 40 ?m, wherein the optical fiber has a cutoff wavelength of between about 870 nm and about 970 nm, and a macrobending loss of below about 1 dB at a wavelength of 1550 nm when wrapped one turn around a 32 mm mandrel.

Abstract: The present invention provides an optical fiber suitable for the manufacture of optical fiber couplers and having low macrobending loss, low cutoff wavelength, low attenuation, and low sensitivity to variations in overclad mass. One aspect of the present invention provides an optical fiber having a core having an index profile, the index profile of the core having a value of &agr; of between about 1.7 and about 3.0; and a cladding region surrounding and in contact with the core, the cladding region having an outer radius of at least about 40 &mgr;m, wherein the optical fiber has a cutoff wavelength of between about 870 nm and about 970 nm, and a macrobending loss of below about 1 dB at a wavelength of 1550 nm when wrapped one turn around a 32 mm mandrel.

Abstract: A glass preform is drawn into a fiber. Holes, running the length of the preform, collapse during the drawing, causing the core to have an elliptical cross section.

Abstract: Optical fiber is provided with a periodically reversing spin while the fiber is pulled through a melt zone. A cooled region of the fiber downstream from the melt zone passes between a pair of opposed elements. The opposed elements are moved so that surface regions engaging the fiber move in opposite lateral directions relative to one another, thus spinning the fiber about its axis. The lateral movement of the engaged surface portions is periodically reversed to reverse the spin direction. The opposed elements may include belts or rollers, which can be tilted to orientations oblique to the longitudinal direction of the fiber.

Abstract: PURPOSE: To form a polarization maintaining optical fiber which is long-sized and improves remarkably a polarization characteristic by forming a core of a circular or elliptical shape and forming a refractive index distribution of said core into a graded type shape.

Abstract: A glass preform (10) is drawn into a fiber. Holes (13), running the length of the preform (10), collapse during the drawing, this causes the core (11) to have an elliptical cross section.

Abstract: Optical fiber is provided with a periodically reversing spin while the fiber is pulled through a melt zone. A cooled region of the fiber downstream from the melt zone passes between a pair of opposed elements. The opposed elements are moved so that surface regions engaging the fiber move in opposite lateral directions relative to one another, thus spinning the fiber about its axis. The lateral movement of the engaged surface portions is periodically reversed to reverse the spin direction. The opposed elements may include belts or rollers, which can be tilted to orientations oblique to the longitudinal direction of the fiber.

Abstract: Optical fiber is provided with a periodically reversing spin while the fiber is pulled through a melt zone. A cooled region of the fiber downstream from the melt zone passes between a pair of opposed elements. The opposed elements are moved so that surface regions engaging the fiber move in opposite lateral directions relative to one another, thus spinning the fiber about its axis. The lateral movement of the engaged surface portions is periodically reversed to reverse the spin direction. The opposed elements may include belts or rollers, which can be tilted to orientations oblique to the longitudinal direction of the fiber.

Abstract: A device for connecting optical fibers is formed by inserting one or more fibers into at least one end of a capillary tube. The bore is tapered to facilitate fiber insertion. To taper the end of a bore, the tube is rotated about its longitudinal axis while a first narrow stream of abrasive particles is directed onto the tube end. The axis of the first stream is located off the axis of the tube bore, thereby forming a taper that is spherical rather than conical. A second stream, the axis of which is coaxial with the bore, is then directed onto the tube end to remove that portion of the tapered aperture adjacent the bore, thereby forming a more funnel-shaped aperture.