A vertical stretching method and equipment for an optical fiber preform

Abstract

The invention discloses a perpendicular stretching method and equipment for an optical fiber perform. The method comprises the steps that a large-diameter optical fiber perform is clamped, pretreatment starts to be performed on the optical fiber perform, and key parameter values in the stretching process are obtained in advance; then, an upper clamping device and a lower clamping device are controlled to synchronously rotate, the large-diameter optical fiber perform is heated to a semi-molten state through a heating device, an upward moving velocity V<3> is applied to the large-diameter optical fiber perform in the perpendicular direction through the upper clamping device, meanwhile, the heating device moves at an upward velocity V<2>, and the outer diameters obtained before and after stretching meet the relation V<3>*the square of D<1>=V<2>*(the square of D<1>-the square of D<2>). By means of the perpendicular stretching method and equipment for the optical fiber perform, the hysteretic nature in a common real-time feedback adjusting mode can be effectively avoided, the influence of the geometric dimension of the large-diameter optical fiber perform on a stretching result can be reduced to the maximum degree, the stretching control precision is improved, and the machining efficiency is further improved.

Description

technical field [0001] The invention relates to a vertical stretching method and equipment for an optical fiber preformed rod. Background technique [0002] In 1970, Corning of the United States first used the vapor deposition method to prepare preforms and pull out low-attenuation optical fibers. At present, there have been many processing methods for making glass preforms for drawing optical fibers. These processing methods include: external vapor deposition (OVD), vapor axial deposition (VAD), internal vapor deposition (IVD), modified chemical vapor deposition (MCVD), and plasma activated chemical vapor deposition (PCVD). [0003] After decades of technological development, the production capacity of both the optical fiber preform and the core rod of the core material of the preform has changed from a small rod of more than ten millimeters to a large one of more than 150 millimeters that we often see now. For rods, YOFC's prefabricated rods can reach a maximum of 200mm a...

AI Technical Summary

Problems solved by technology

Patent document CN 1890189A discloses a method and equipment for stretching optical fiber base materials in the horizontal direction. However, due to the gravity of the rod itself, the bow of the preform rod cannot be well controlled during the stretching process. will cause more trouble

The patent document CN102627399B discloses a method and equipment for stretching optical fiber base materials in the vertical direction, but in the stretching process, only the size of the rod after stretching is concerned, and the rod reaching 80 mm or more must be melted when heated. It is very slow. When it is detected that the stretching effect is not good, the relevant stretching parameters will be adjusted. After the relevant parameters are adjusted, the impact will be reflected in the stretching effect. Hysteresis; at the same time, the inhomogeneity of the thermal field in the furnace during the heating process of the stretching furnace leads to uneven heating of the master rod during stretching, which will greatly affect the size, roundness and bow control of the preform after stretching. , which leads to a decrease in the drawing efficiency and the geometric and optical properties of the preform or mandrel after stretching, which leads to an increase in production costs and a great waste of raw materials for the preform

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