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:
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:
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 relates to a method for precisely elongating a glass preform of an optical fiber body having a desired outer diameter. In this method, a predetermined part of the glass preform is elongated as tensile stress is applied to one end of the glass preform while a predetermined part of the glass preform is heated and softened successively from one end toward the other end of the glass preform. In this elongating operation, while the outer diameter of the softening portion of the glass preform is measured, the tensile stress is adjusted such that the outer diameter of the softening portion coincides with a preset value of the control outer diameter. In particular, this method is characterized in that the preset value of the control outer diameter is changed at least during a predetermined period until termination of elongation or during a predetermined period from the start of elongation.
摘要:
An object of this invention is to provide a mode field diameter conversion optical fiber which can be processed in a short period of time to have a reduced mode field diameter at a desired portion thereof. The optical fiber according to this invention comprises a core of silica glass having a residual tensile stress, and a cladding surrounding the core and having a lower refractive index than that of the core. The desired portion is heated to relax the residual tensile stress in the core, whereby the optical fiber has a reduced mode field diameter at the desired portion.
摘要:
A glass preform for an optical fiber is flame abrased with an oxyhydrogen flame while vertically suspending and rotating the glass preform and relatively moving one or both of the glass preform and the oxyhydrogen flame, whereby a surface of the glass preform is smoothened.
摘要:
The present invention relates to an OFA having a high signal gain, easily manufactured, having a high mechanical strength, having a small splice loss with respect to other optical fibers, and rarely encountering the occurrence of noise at a signal wavelength. The OFA according to the present invention has a function of amplifying signals propagating therethroug by pumping light supplied thereto, and comprises, at least, a core region, an inner cladding region provided on the periphery of the core region, an outer cladding region provided on the periphery of the inner cladding region, and one or more node coupling gratings. An element for signal amplification is added to at least the core region. The core region has a structure ensuring a core mode with respect to the signals, while the inner cladding region has a structure ensuring a multi-mode with respect to the pumping light. Each of the mode coupling gratings passes core mode signals therethrough, and induces a mode coupling between the inner cladding mode and the core mode with respect to the pumping light.
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:
There is provided a process of melt drawing an optical fiber from a preform therefor in which a heating furnace comprising a muffle tube inside thereof through which the optical fiber is passed is provided immediately below a melt drawing furnace to further draw the optical fiber while heated, and an interior of the muffle tube is kept in an atmosphere selected from the group consisting of an inert atmosphere, an atmosphere comprising oxygen gas and an atmosphere comprising hydrogen gas.