摘要:
The present invention providesa process for the dehydrating and purifying treatment by heating a porous glass preform for an optical fiber comprising passing the porous glass preform through a muffle tube having a SiC layer at least on its inner surface at a high temperature under an atmosphere comprising an inert gas and a silicon halogenide gas;a process for the fluorine-doping treatment by heating a porous glass preform for an optical fiber comprising passing a porous glass preform through a muffle tube having a SiC layer at least on its inner surface at a high temperature under an atmosphere comprising a fluorine compound gas and an inert gas; anda process for the vitrifying treatment by heating a porous glass preform for an optical fiber comprising passing the preform, which has been previously dehydrated and purified, through a muffle tube having a SiC layer at least on its inner surface at a high temperature under an atmosphere gas.
摘要:
A heating furnace for heating a porous preform made of fine particles of quartz base glass for an optical fiber which comprises a heater and a muffle tube positioned inside the heater to separate a heating atmosphere from the heater, wherein the muffle tube body consists of highly pure carbon and an inner wall and an outer wall of the body is coated with a carbon material selected from the group consisting of pyrolytic graphite and solid-phase carbonized glassy carbon.
摘要:
The present invention providesa process for the dehydrating and purifying treatment by heating a porous glass preform for an optical fiber by passing the porous glass preform through a muffle tube having a SiC layer at least on its inner surface at a high temperature under an atmosphere containing an inert gas and a silicon halogenide gas;a process for the fluorine-doping treatment by heating a porous glass preform for an optical fiber by passing a porous glass preform through a muffle tube having a SiC layer at least on its inner surface at a high temperature under an atmosphere containing a fluorine compound gas and an inert gas; anda process for the vitrifying treatment by heating a porous glass preform for an opticla fiber by passing the preform, which has been previously dehydrated and purified, through a muffle tube having a SiC layer at least on its inner surface at a high temperature under an atmosphere gas.
摘要:
There is provided a heating furnace comprising a furnace body, a cylindrical zone heater in the furnace body, a muffle tube installed through the furnace body for thermally treating a porous preform made of high purity quartz glass by moving the preform vertically therethrough and a partition means in the portion of the muffle tube projecting above the furnace body to divide an interior space of the muffle tube into an upper space and a lower one.
摘要:
An optical fiber preform 2 having a viscosity ratio R&eegr;=&eegr;0/&eegr;t of 2.5 or less between the core average viscosity &eegr;0 and the total average viscosity &eegr;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&eegr;≦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.
摘要:
In order to provide an improved process for the production of a glass preform for an optical fiber which includes substantially no bubble formation therein and also has a substantially uniform shape, the present invention provides a process for the production of a glass preform which is at least partially formed from silica. In particular, a body is formed on a rod by depositing fine glass particles thereon, 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. According to this process, the heating includes 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.
摘要:
A drawing apparatus 1 comprises a drawing furnace 11, a protecting tube 21, and a resin curing unit 31. A buffer chamber 41 is disposed between the drawing furnace 11 and the protecting tube 21, and has a length L1 in the drawing direction of the optical fiber 3. The buffer chamber 41 is constituted by a first buffer cell 42 and a second buffer cell 45. In the space within the buffer chamber 41, an He gas, which is an atmosphere gas within the drawing furnace 11, and the air, which is an atmosphere gas within the protecting tube 21, exist in a mixed state. The optical fiber 3 drawn upon heating in the drawing furnace 11 is fed to the protecting tube 21, and a predetermined part of the optical fiber 3 is annealed at a predetermined cooling rate. Thereafter, a coating die 62 coats the optical fiber 3 with a UV resin solution 63, and the resin curing unit 31 cures the UV resin 63, whereby a coated optical fiber 4 is obtained.
摘要:
A raw material supplying device having a gas tight tank for receiving a material to be gasified by heating; a heater for heating the raw material within the tank and a plurality of pipes for conveying a plurality of streams of gas in parallel to each other to a plurality of ports of a reaction apparatus, and a process for using the raw material supplying device. The raw material supplying device can be used in a system for manufacturing glass fibers in which the ends of the plurality of pipes are connected to the gas feed ports of at least one multi-layer burner.
摘要:
Based on an intermediate 20A in which a cladding portion 22 is formed on the outer periphery of a core portion 21, a pair of holes 23 and 24 are provided parallel to the z axis on both sides of the core portion 21 within the cladding portion 22, and an intermediate 20 is thereby fabricated. In this intermediate 20, 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 part 33 is inserted into a hole 23 of the intermediate 20, and a cylindrical stress applying part 34 is inserted into a hole 24 thereof. Thus, a preform 40 is formed. These materials are drawn and integrated together, and a polarization maintaining optical fiber is thereby manufactured.
摘要:
A heating furnace for heating a porous preform made of fine particles of highly pure quartz glass for an optical fiber, which furnace comprises a cylindrical furnace body, a heater installed in said furnace body and a muffle tube installed inside said heater to separate a heating atmosphere from said heater, wherein said muffle tube is made of highly pure carbon and coated with a gas impermeable carbon, which furnace prevents contamination of the preform with impurities and has long life.