Sumitomo Electric Industries, Limited

Nippon Telegraph and Telephone Corporation

Yasuo Matsuda

Toshifumi Hosoya

Yuji Kobayashi

Tsuyoshi Nonaka

Nobuhiro Akasaka

Tatsuya Kakuta

Kazumasa Oishi

Atsushi Suzuki

Kohei Kobayashi

Ichiro Yoshimura

Toru Yamanishi

Katsuya Nagayama

Shigeru Tomita

Yutaka Wada

Takashi Fujii

Ichiro Tsuchiya

Gotaro Tanaka

Kunio Fujiwara

Makoto Honjo

Kazuya Kuwahara

Katsuyuki Tsuneishi

Yoshiki Chigusa

Takayuki Mishima

Kazuki Sogabe

Hiroaki Ohta

Hideo Miyaki

Wataru Katsurashima

There is provided an optical fiber drawing furnace capable of drawing an optical fiber having small non circularity, which drawing furnace includes a muffle tube, in which an optical fiber preform is supplied, a heater surrounding the muffle tube, a plurality of electrode connecting portion extending from the heater, a plurality of electrodes connected to electrode connecting portions, and in conjunction therewith to an electric power source, and unifying means for unifying the temperature distribution along the circumferential direction.

Optical fiber drawing furnace with a zig zag heating element

A coated optical fiber comprising a drawn glass fiber, and a primary coating and a secondary coating which are formed by photo-curing primary and secondary coating resins simultaneously applied to an outer periphery of the glass fiber, wherein an adhesion force S (g/cm) at an interface between the primary coating resin after curing and the glass fiber is at least {fraction (1/13)} ((g/cm)/&deg; C.) with respect to a glass transition temperature Tg (&deg; C.) of the secondary coating resin after curing.

Coated optical fiber and method of making the same

A coated optical fiber comprising a glass fiber constituted by a silica based glass core and cladding; and a primary coating and a secondary coating which are formed by photo-curing a primary coating resin layer and a secondary coating resin layer which are applied to an outer periphery of the glass fiber, wherein a maximum value A,of absorbances A,of the secondary coating resin layer before curing with respect to light in a wavelength region of 310 to 340 nm is not more than 0.5, whereas absorbances A,of the primary coating resin layer before curing with respect to light in this wavelength region are greater than the absorbances A,.

Coated optical fiber and its manufacturing method

This invention concerns a large-diameter optical fiber that is improved in the bandwidth and bending loss and that can be produced at low cost with higher productivity. The optical fiber comprises an inner core having a refractive index profile in which refractive indices increase toward the center axis thereof, an outer core provided outside the inner core and having a constant refractive index not more than the minimum refractive index of the inner core, and a cladding provided outside the outer core and containing a plastic material having a refractive index lower than that of the outer core. In the optical fiber, total refractive index difference (.DELTA.n.sub.total), defined as the difference between the maximum refractive index of the inner core and the refractive index of the cladding, is not less than 0.015 and not more than 0.1; and a outside core diameter of the outer core (d.sub.1) is not less than 100 .mu.m and not more than 500 .mu.m.

Optical fiber

A coated glass fiber for light transmission consisting of a glass fiber for light transmission and at least one coating layer made of a UV-curing resin, wherein an outermost layer of the coating layer is made of a UV-curing resin having a Young's modulus of at least 100 kg/mm.sup.2 and a change of a cure shrinkage degree of 1% or less after a Young's modulus reaches one tenth of an end Young's modulus, which has good lateral pressure characteristics and low transmission loss.

Optical glass fiber

A process is provided for producing a plastic optical fiber by drawing while melting an optical fiber preform under heating. The optical fiber preform includes at least a core containing an organic polymer and a cladding layer disposed on the outer circumference of the core and containing an organic polymer. The drawing is conducted under a drawing tension of 10 g or more, and preferably under a drawing tension of 100 g or less, until winding-up of the optical fiber.

Plastic optical fiber preform, and process and apparatus for producing

A process and an apparatus for producing a preform for plastic optical fiber having a refractive index distribution in which the refractive index is gradually decreased from the center of the preform toward the outer periphery thereof, by depositing a deposition layer comprising a polymer A (refractive index: N.sub.a) and a refractive index modifier having a refractive index different from that of the polymer A onto a surface of a rod member rotating about an axis thereof, by use of vapor-phase deposition based on a CVD (Chemical Vapor Deposition) process, or a coating process. A plastic optical fiber preform including deposition layers having a gradually decreasing refractive index distribution is formed by changing the mixing ratio between the polymer A and the refractive index modifier constituting the deposition layer.

Plastic optical fiber preform having a jacket layer

A process for producing a preform for elastic optical fiber having a refractive index distribution in which the refractive index is gradually decreased from the center of the preform toward the outer periphery thereof, by depositing a deposition layer comprising a polymer A (refractive index: N.sub.a) and a refractive index modifier having a refractive index different from that of the polymer A onto an inner surface of a hollow cylindrical member rotating about an axis thereof, by use of vapor-phase deposition based on a CVD (Chemical Vapor Deposition) process, or a coating process. A plastic optical fiber preform comprising deposition layers having a gradually increasing refractive index distribution is formed by changing the mixing ratio between the polymer A and the refractive index modifier constituting the deposition layer.

A coated optical fiber comprising a light-transmitting fiber and a resin coating layer disposed on the outer periphery of the light-transmitting fiber is formed, an external flaw is imparted to the surface of the resin coating layer while running the coated optical fiber, and then the coated optical fiber is subjected to the measurement of a tensile breaking strength thereof. At this time, the fiber having a strength retention ratio R.sub.S =S.sub.A /S.sub.0 of 0.98 or more, wherein S.sub.A is the median value of the tensile breaking strength after the provision of the external flaw, and S.sub.0 is the median value of the tensile breaking strength before the provision of the external flaw, is selected as a non-defective product.

Coated optical fiber

Coated optical fiber and fabrication process therefor

A physical property evaluation method for optical fiber coating which is easy in producing a sample and high in accuracy and which is capable of measuring the shear modulus or tensile modulus with high accuracy, and a coated optical fiber with good lateral pressure characteristics using this evaluation method. The method comprises a step of producing a sample with the both end faces being parallel by cutting a coated optical fiber by a plane normal to the direction of the center axis of an optically transparent member, a step of holding the sample by securing the second coating layer, a step of pushing only the optically transparent member to impose a load thereon, thereby giving displacement to the optically transparent member and causing shear elastic deformation to the first coating layer, and a step of calculating the shear modulus or tensile modulus of a material forming the first coating layer, based on an amount of the displacement of the optically transparent member and a value of the load imposed thereon.

Physical property evaluation method for optical fiber coating, and

A winding reel for optical fiber is provided with a drum and a flange. The flange is provided with first and second slits therein for receiving leading and trailing (frontward and rearward) portions of the optical fiber. The length of the slit that receives the forward end of the optical fiber extends from the outer periphery of the flange to the surface of the drum. The slit for receiving the rearward end of the optical fiber is shorter than the forward end receiving slit. The rearward end receiving slit extends from the outer periphery of the flange inwardly a distance such that the slit does not reach a position at which a maximum amount of optical fiber wound on the winding reel is located.

Slitted winding wheel for optical fiber

An optical switch comprises a substrate, a first thin film layer formed on the substrate and including a first optical waveguide having a coupling portion and tapered portions therein, a clad layer formed on the thin film layer, a second thin film layer formed on the clad layer and including a second optical waveguide having a coupling portion and tapered portions, wherein a compound including a photochromic material is contained in the clad layer.

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Yokohama, Japan

Yasuo Matsuda