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    FURNACE FOR PRODUCTION OF OPTICAL FIBER PREFORM
    41.
    发明专利
    FURNACE FOR PRODUCTION OF OPTICAL FIBER PREFORM 未知

    公开(公告)号：CA2025880A1

    公开(公告)日：1991-03-26

    申请号：CA2025880

    申请日：1990-09-20

    Applicant: SUMITOMO ELECTRIC INDUSTRIES

    Inventor： TSUCHIYA ICHIRO ,  SAITO MASAHIDE ,  ISHIKAWA SHINJI ,  OHGA YUICHI ,  KANAMORI HIROO

    IPC: C03B37/014 ,  C03B20/00 ,  F27B5/00 ,  C03B37/012 ,  F27B5/08

    Abstract: The present invention provides a furnace comprising a muffle tube made of a gas impermeable and heat resistant material, a heater in a furnace body which surrounds the muffle tube and an inner cylinder made of a heat resistant material which is detachably fitted inside the muffle tube near the heater for a thermal treatment of a quartz glass preform by inserting the preform in the muffle tube, wherein said muffle tube comprises a material selected from a group consisting of highly pure carbon coated with gas impermeable silicon carbide, sintered silicon carbide coated with gas impermeable silicon carbide, gas impermeable silicon carbide and highly pure carbon coated with gas impermeable carbon, and said inner cylinder comprises a material selected from a group consisting of highly pure carbon, highly pure carbon coated with gas impermeable silicon carbide and highly pure carbon coated with gas impermeable carbon.

    Optical fiber and method of making the same
    46.
    发明专利
    Optical fiber and method of making the same 未知

    公开(公告)号：AU773229B2

    公开(公告)日：2004-05-20

    申请号：AU6549701

    申请日：2001-08-27

    Applicant: SUMITOMO ELECTRIC INDUSTRIES

    Inventor： NAGAYAMA KATSUYA ,  OHGA YUICHI ,  SAITOH TATSUHIKO ,  ISHIKAWA SHINJI ,  TSUCHIYA ICHIRO ,  UCHIYAMA TAKENORI

    IPC: C03B37/027 ,  C03B37/029 ,  C03B37/15 ,  G02B6/02 ,  G02B6/036 ,  G02B6/16 ,  B29D31/00

    Abstract: An optical fiber preform 2 having a viscosity ratio R eta = eta 0/ eta t of 2.5 or less between the core average viscosity eta 0 and the total average viscosity eta t is prepared, and is drawn by a drawing furnace 11 so as to yield an optical fiber 3, which is then heated to a temperature within a predetermined range so as to be annealed by a heating furnace 21 disposed downstream the drawing furnace 11. Here, upon annealing in the heating furnace 21, 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 eta ≤ 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.

    49.
    发明专利
    未知

    公开(公告)号：DE69209174T3

    公开(公告)日：1999-08-19

    申请号：DE69209174

    申请日：1992-07-16

    Applicant: SUMITOMO ELECTRIC INDUSTRIES

    Inventor： DANZUKA TOSHIO ,  ITO MASUMI ,  TSUCHIYA ICHIRO

    IPC: C03B37/014

    Abstract: A transparent glass preform (1) for an optical fiber is produced by heating a glass soot preform (1) to remove gas from the soot preform at a temperature at which the soot preform is not vitrified under reduced pressure, and then heating the preform (1) at a temperature at which the preform is vitrified under reduced pressure, whereby the transparent glass preform containing no or little bubbles and having a uniform outer diameter is produced.

    50.
    发明专利
    未知

    公开(公告)号：DE69412308D1

    公开(公告)日：1998-09-17

    申请号：DE69412308

    申请日：1994-03-01

    Applicant: SUMITOMO ELECTRIC INDUSTRIES

    Inventor： ITO MASUMI ,  DANZUKA TOSHIO ,  OHGA YUICHI ,  HOSHINO SUMIO ,  TSUCHIYA ICHIRO

    IPC: C03B8/04 ,  C03B20/00 ,  C03B37/014 ,  G02B6/00

    Abstract: In order to provide an improved process for the production of a glass preform for an optical fiber which includes substantially no bubble therein and also have a substantially uniform shape, there is provided a process for the production of a glass preform which comprises at least silica for an optical fiber comprising producing a body comprising a rod on which fine glass particles are deposited preferably by the vapor phase reactions and heating the body to vitrify under a reduced atmosphere or a vacuumed atmosphere so that the glass preform is produced; in which process the heating comprises a first heating step of degassing the body at a first heating temperature, a second heating step of shrinking the body at a second heating temperature which is higher than the first heating temperature and which is lower than a third heating temperature, and a third heating step of vitrifying the shrunken body at the third temperature which corresponds to a vitrification temperature of the fine glass particles so as to produce the glass preform.

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