Sumitomo Electric Industries, Limited

Nippon Telegraph and Telephone Corporation

Kyushu University

Ichiro Tsuchiya

Shinji Ishikawa

Katsuya Nagayama

Kazuya Kuwahara

Yuichi Ohga

Toshio Danzuka

Kohei Kobayashi

Hiroshi Yokota

Hiroo Kanamori

Masumi Ito

Toshiki Taru

Kaoru Okuno

Yoichi Ishiguro

Michihisa Kyoto

Kazumasa Oishi

Hiroaki Ohta

Motoki Kakui

Tomoyuki Hattori

Katsuyuki Tsuneishi

Masahide Saitoh

Hideo Miyaki

Ken Takahashi

Toshiaki Kakii

Masashi Onishi

Akira Inoue

Masayuki Shigematsu

Tetsuya Haruna

Tomohiko Ueda

Yoshikyo Tamekuni

Shinji Nagasawa

Sumio Hoshino

Yasuo Matsuda

Hiroaki Takimoto

Takahiro Murata

Masahiro Takagi

Tatsuhiko Saito

Iwao Okazaki

Masahide Saito

Tatsuhiko Saitoh

Hideki Minami

Toshimi Habasaki

Motohide Yoshida

Kazuyuki Soma

Yasuhiro Naganuma

Takenori Uchiyama

Tetsuo Shiota

A laser light source includes a light source section for outputting pulse laser light &#x3bb;, &#x3bb;with a mutually identical repetition frequency, an optical amplification section for amplifying and outputting the pulse laser light &#x3bb;, &#x3bb;output from the above light source section by means of a common optical amplification medium, an optical demultiplexing section for mutually demultiplexing pulse laser light &#x3bb;, &#x3bb;, an optical multiplexing section for multiplexing and outputting the pulse laser light &#x3bb;, &#x3bb;demultiplexed in the above optical demultiplexing section, and an optical path length difference setting section for adjusting an optical path length difference between the pulse laser light &#x3bb;, &#x3bb;in between the optical demultiplexing section and the optical multiplexing section.

Laser light source, method of laser oscillation, and method of laser processing

The present invention provides fluorescent glass containing at least 50 mol % of at least one kind of oxide selected from the group consisting of SiO, GeO, and POas a glass constituent of a region containing a Bi ion as a dopant.

Fluorescence glass, optical wave guide for optical amplifier and optical amplifier module

Based on an intermediateA in which a cladding portionis formed on the outer periphery of a core portion, a pair of holesandare provided parallel to the z axis on both sides of the core portionwithin the cladding portion, and an intermediateis thereby fabricated. In this intermediate, a width Ry in the y-axis direction is made smaller than a width Rx in the x-axis direction. Moreover, a cylindrical stress applying partis inserted into a holeof the intermediate, and a cylindrical stress applying partis inserted into a holethereof. Thus, a preformis formed. These materials are drawn and integrated together, and a polarization maintaining optical fiber is thereby manufactured.

Polarized wave holding optical fiber, and method of producing the same

A drawing apparatuscomprises a drawing furnace, a protecting tube, and a resin curing unit. A buffer chamberis disposed between the drawing furnaceand the protecting tube, and has a length Lin the drawing direction of the optical fiber. The buffer chamberis constituted by a first buffer celland a second buffer cell. In the space within the buffer chamber, an He gas, which is an atmosphere gas within the drawing furnace, and the air, which is an atmosphere gas within the protecting tube, exist in a mixed state. The optical fiberdrawn upon heating in the drawing furnaceis fed to the protecting tube, and a predetermined part of the optical fiberis annealed at a predetermined cooling rate. Thereafter, a coating diecoats the optical fiberwith a UV resin solution, and the resin curing unitcures the UV resin, whereby a coated optical fiberis obtained.

Optical fiber producing method

The drawing method of the present invention uses a drawing furnace comprising a furnace muffle tube, a furnace body and a heater. According to the method, an optical fiber preform is inserted from the inlet of the furnace muffle tube, the optical fiber preform is melted by means of a heater, under a specified gas atmosphere, and is drawn toward the outlet of the furnace muffle tube by means of a specified drawing tension. The optical fiber preform and the drawing furnace used in this method both satisfy the condition of below-indicated formula (1):&#x2267;8&#x2003;&#x2003;(1)wherein L indicates the length of the furnace body in the drawing direction and D indicates the diameter of the optical fiber preform. Through this method, even for the case of drawing optical fibers having a large relative index difference between the central core and the cladding, optical fibers wherein residual amounts of lattice defects are sufficiently reduced and degradation of characteristics under a hydrogen atmosphere is sufficiently suppressed can be obtained efficiently and at low cost.

Drawing method of optical fiber and drawing furnace

A furnace for drawing an optical fiber provided with a muffle tube ( ) and inner tubes ( &prime;) connected to the upper end of the core tube, wherein a preform ( ) supported by a dummy rod ( ) at the upper part thereof is disposed inside the muffle tube ( ) and inner tubes ( &prime;) so as to be movable downward together with dummy rod ( ), the preform ( ) is heated and melted by a heater ( ) from the outside of the muffle tube ( ) and an optical fiber ( ) is pulled out from the lower end of the preform ( ); the furnace is further provided with one or a plurality of sets of separating plates ( ) adapted to partition a space in the inner tubes ( &prime;) above the preform ( ) into a plurality of portions in the advance direction of the preform and disposed in the space, and with gas blowing inlets ( ) disposed in the parts of wall surfaces of the inner tubes ( &prime;) which are below the separating plates ( ) and adapted to blow an inert gas into the inner tubes ( &prime;) and the muffle tube ( ), thereby preventing variations in diameter of the optical fiber ( ).

Method of controlling an upper portion of an optical fiber draw furnace

A fiber drawing method according to the present invention is a drawing method of optical fiber for drawing an optical fiber from one end of a fiber preform by softening with heat, wherein the fiber preform is set in a semi-closed space opening in part at a lower end in a fiber drawing furnace, the fiber preform is heated by a heater disposed on the lower end side of this semi-closed space and fiber drawing is carried out with adjusting a quantity of heat dissipation from the upper portion of this semi-closed space.

Optical fiber drawing method and drawing furnace

Optical fiber drawing furnace having adjustable partitions

In an optical fiber coating method comprising the steps of; applying an injecting first coating resin to the outer periphery of the optical fiber while inserting the optical fiber through a first die hole provided in a first coating die; and applying an injected second coating resin onto the first coating resin while inserting the optical fiber through a second die hole provided in a second coating die. Wherein a disk-shaped upper end face of the second coating die and a basically disk-shaped lower end face of the first coating die having a protrusion formed around the first die hole and projecting in the passing direction of the optical fiber are opposed to each other so as to arrange the first and second die holes concentrically, and the second coating resin is injected into the second die hole by way of a gap formed between the lower end face of the first coating die and the upper end face of the second coating die, so as to reduce an annular lower-pressure region formed around the optical fiber in a flow of the second coating resin within the gap.

Optical fiber coating method and coating apparatus

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

In an optical fiber coupler making apparatus which makes an optical fiber coupler by thermally fusing a plurality of optical fibers together by use of a heater and then elongating thus thermally fused part, the heater comprises a heating element which is made of zirconia and which has a slit for containing the optical fibers. The inner face of the heating element is preferentially heated due to a characteristic of its material. Consequently, if optical fibers are contained in the fiber receiving slit, then they can be thermally fused at a sufficiently high temperature in a short period of time, whereby reducing mingling of impurities into the optical fiber coupler. Therefore, the heating element made of zirconia is effective as means for preventing impurities from mingling from the outside thereof. Also, performances of the heating element can be maintained over a long period of time even if the optical fibers are thermally fused at a high temperature. Further, the evaporation of impurities, which may adversely affect characteristics of the optical fiber coupler, hardly occurs from the heating element.

Optical fiber coupler making apparatus made from zirconia and method

Method of making an optical fiber with an improved UV-curable resin

The amount of dimming components originating in an ultraviolet-curing resin and adhering to a quartz tube is reduced, and a decline in the ultraviolet transmittance is prevented, during ultraviolet-curing of a resin coated on a liner body through an ultraviolet-transmitting tubular member placed inside a curing apparatus and of curing ultraviolet-curing resin by irradiating ultraviolet rays from outside the ultraviolet-transmitting tubular member. Embodiments include coating the inner surface of the ultraviolet-transmitting tubular member with titanium and employing an atmosphere of lover 0.1% oxygen.

Method and apparatus for curing ultraviolet-curing resin

An optical fiber preform having a viscosity ratio R&eegr;&equals;&eegr; /&eegr; of 2.5 or less between the core average viscosity &eegr; and the total average viscosity &eegr; is prepared, and is drawn by a drawing furnace so as to yield an optical fiber which is then heated to a temperature within a predetermined range so as to be annealed by a heating furnace disposed downstream the drawing furnace Here, upon annealing in the heating furnace the fictive temperature Tf within the optical fiber lowers, thereby reducing the Rayleigh scattering loss. At the same time, the viscosity ratio condition of R&eegr;&lE;2.5 restrains the stress from being concentrated into the core, thereby lowering the occurrence of structural asymmetry loss and the like. Hence, an optical fiber which can reduce the transmission loss caused by the Rayleigh scattering loss and the like as a whole, and a method of making the same can be obtained.

Optical fiber and method of making the same

An apparatus for producing optical fiber ribbons which has a optical fiber gathering device, one or more coating applicators and a turn roller arranged in a straight line, with one or more alignment guide in plate form being provided on a travelling line of optical fibers or optical fiber ribbons upstream of the coating applicator. The alignment guide is chamfered to arch form on the side that contacts the optical fibers or the optical fiber ribbons. The alignment guide suppresses the optical fibers or the optical fiber ribbons from vibrating in a direction perpendicular to the direction of the arrangement of the optical fibers or the optical fiber ribbons.

Method and apparatus for producing optical fiber ribbons

Growing community of inventors

Yokohama, Japan

Ichiro Tsuchiya