摘要:
Natural or synthetic silica is deposited on a preform set into rotation in front of a plasma torch which moves back and forth substantially parallel to a longitudinal direction of the preform, a first feed duct feeds the plasma with grains of natural or synthetic silica while a second feed duct feeds the plasma with a fluorine or chlorine compound, preferably a fluorine compound, mixed with a carrier gas. Any sodium or lithium contained in the grains of natural or synthetic silica react with the fluorine or chlorine of the fluorine or chlorine compound, thereby making it possible to improve the optical quality of fibers drawn from a preform built up with natural or synthetic silica, and to do so at reduced cost.
摘要:
A method of using a plasma to build up an optical fiber preform consists in injecting hydroxyl ions in a controlled manner into the build-up silica that is deposited on the preform. The invention is applicable to the manufacture of optical fibers, in particular monomode fibers.
摘要:
Highly accurate centering of an optical fiber within a primary cladding deposited by a coating device is carried out by automatic regulation during the fiber-drawing process in order to optimize the mechanical properties of the fiber. The position of the coating device is controlled in dependence on the position of the fiber with respect to an origin of coordinates (O) determined by optoelectronic means. The frusto-conical lower end of the coating die is maintained at each instant by electronic and electromechanical means at the point (O') located at this level on the straight-line segment (OR) which joins the origin to the first point of contact of the fiber with the pulley used for guiding the fiber towards a storage drum.
摘要:
In the drawing of an optical fibre from a glass preform or gathering mould maintained at an appropriate temperature, a process and a system is described for controlling and regulating the characteristics of the optical fibre. To this purpose the fibre formation temperature within the drawing furnace is controlled by a measurement of the tensile stress. The heating of the furnace is regulated, while maintaining constant the tensile stress on the glass fibre at the fibre formation point. A gauge with an electronic measuring bridge is used to carry out a measurement at the preform suspension point, while correcting the effect of the weight reduction of the preform during drawing.