Fujikura Limited

Chiba University

Munehisa Fujimaki

Koichi Harada

Takahiro Hamada

Kuniharu Himeno

Kazuhiko Aikawa

Ryozo Yamauchi

Keiji Ohashi

Shunichirou Hirafune

Shogo Shimizu

Takaaki Suzuki

Masakazu Nakayama

Hiroyuki Sawano

Kenji Yamashiro

Yukinari Shirako

Yutaka Nagasawa

Kenji Okada

Takayuki Kitamura

Koji Omichi

Koichi Takahashi

Akihiko Yoshikawa

Akihito Imase

Yoshikazu Kaifuchi

Koji Tsuru&sacute;aki

An optical fiber is provided. The optical fiber has a refractive index profile that includes a central core, an inner cladding layer, a trench layer, and an outer cladding layer. A trench layer is provided with a reduced refractive index. The optical fiber has a large effective area without having an increase of a cutoff wavelength, and exhibits low macrobending loss.

Optical fiber and method of manufacturing the same

A method of producing a zinc oxide-based semiconductor crystal, including: introducing at least zinc and oxygen on a surface of a substrate; and growing a zinc oxide-based semiconductor crystal on the substrate, wherein a total or partial portion of the zinc is ionized in a vacuum atmosphere of 1&#xd7;10Torr or less and is introduced to the surface of the substrate to grow the ZnO based semiconductor crystal. As a result, it is possible to provide a method of producing a zinc oxide based semiconductor crystal capable of growing a zinc oxide semiconductor crystal having excellent surface flatness and crystallinity and including an extremely small amount of impurities at a high growth rate.

Method of producing zinc oxide semiconductor crystal

A drawing method for a bare optical fiber, comprises the steps of: melting an optical fiber preform using a heating device and drawing the bare optical fiber; and naturally cooling down the bare optical fiber or forcibly cooling down the bare optical fiber by a cooling device after the heating and melting step, wherein a temperature history during the drawing the optical fiber preform to obtain the bare optical fiber in the heating device satisfies a relational expression: T&#x2266;&#x2212;0.01X+12 where a time period when the heated and molten portion of the optical fiber preform heated and molten by the heating device reaches 1800&#xb0; C. or higher is T (min) and a OH group concentration in a cladding layer of the optical fiber preform is X (wtppm).

Drawing method for bare optical fiber with suppressed hydrogen diffusion

A treatment method for an optical fiber including accommodating an optical fiber inside a treatment chamber; introducing a deuterium containing gas into the treatment chamber; and in a deuterium treatment step, exposing the optical fiber to atmosphere of the deuterium containing gas. In the deuterium treatment step, a deuterium concentration D in the treatment chamber during the deuterium treatment is calculated from an initial value A of a deuterium concentration in the deuterium containing gas inside the treatment chamber, a concentration B of oxygen in an ambient atmosphere of the treatment chamber, and a concentration C of oxygen in the deuterium containing gas inside the treatment chamber, and the deuterium concentration in the treatment chamber is controlled based on the deuterium concentration D calculated. Other gases such as hydrogen containing gas or nitrogen containing gas may also be used according to the invention.

Treatment method for optical fiber

A dispersion compensating optical fiber for NZ-DSFs, includes: an uncovered dispersion compensating optical fiber; a double-layered resin coating disposed around the uncovered dispersion compensating optical fiber; and an outer coating layer having a thickness of 3 to 7 &#x3bc;m, containing silicone in an amount of 1 to 5% by weight, and disposed around the double-layered resin coating. The outer diameter of the uncovered dispersion compensating optical fiber is in a range from 90 to 125 &#x3bc;m, an outer diameter of the dispersion compensating optical fiber is in a range from 180 to 250 &#x3bc;m, and the amount of silicone contained in the outer coating layer is determined such that an adhesive property of the outer coating layer is 1 gf/mm or less.

Dispersion compensating optical fiber and dispersion compensating optical fiber module

A method of treating optical fiber includes at least a first step of creating a reduced-pressure atmosphere in a space which holds the optical fiber, and a second step of introducing to the space a deuterium-containing gas so as to expose the optical fiber to the gas.

Method for treating optical fiber and apparatus for treating optical fiber

An optical fiber coating die is made such that an interfacial shear rate of the optical fiber to the resin coat is calculated in accordance with a pressure value of resin inside a coating cup, and the interfacial shear rate is in a range of &#x2212;1.5&#xd7;105 to 0 sec&#x2212;1. Also, an optical fiber drawing die is made such that the interfacial shear rate of the optical fiber to the resin coat is calculated in accordance with a diameter of a coating resin, and the interfacial shear rate is in a range of range of &#x2212;3&#xd7;105 to 2&#xd7;105 sec&#x2212;1. By doing this, an optical fiber drawing die which can be used in an optical fiber drawing method so as to realize stable resin coating operation even in high-speed drawing operation and high productivity can be realized.

Optical fiber drawing die and drawing method therefor

A dispersion compensating optical fiber includes an uncovered dispersion compensating optical fiber containing a core and a cladding, and a resin coating which is disposed around the uncovered dispersion compensating optical fiber, wherein the resin coating has an adhesive property of 10 g/mm or less, and which includes an outer coating layer which is formed to have a thickness of 3 &#x3bc;m or more, and the outer diameter of the uncovered dispersion compensating optical fiber is in a range from 90 to 125 &#x3bc;m, and the outer diameter of the dispersion compensating optical fiber is in a range from 180 to 250 &#x3bc;m.

When an optical fiber is formed by drawing a preform , twisting is generated in the optical fiber . An outer diameter of the optical fiber is continuously measured along a longitudinal direction of the optical fiber from two different directions in a plane perpendicular to the advancing direction of the optical fiber by a device for measuring twisting , thus twisting of the optical fiber is measured.

Method for measuring the twisting of an optical fiber, and a method and apparatus for manufacturing optical fibers

A manufacturing method and apparatus for manufacturing a coated optical fiber which has a superior surface smoothness of a resin coating and which can be coated with a colored ink with high coating performance. In the method including the steps of making a coated optical fiber by forming an outer coating layer around a bare optical fiber; and winding the coated optical fiber via pulleys by a take-up, the surface roughness of each solid body which the outer layer of the running coated optical fiber contacts is 0.8 &mgr;m or less. When the temperature of the outer coating layer is a room temperature or the Young's modulus of the outer coating layer is higher than 500 MPa, the surface roughness of each solid body, which the outer layer of the coated optical fiber contacts during drawing or rewinding, is 1.2 &mgr;m or less.

Growing community of inventors

Sakura, Japan

Munehisa Fujimaki