Method of measuring optical fiber drawing tensile force

Abstract

A method of measuring optical fiber-drawing tension, containing: measuring oscillation of an optical fiber when drawing; determining a fundamental oscillation frequency of the optical fiber based on peak frequencies contained in spectrum components of oscillation waveform; and converting the fundamental oscillation frequency into tension applied to the optical fiber being drawn; wherein the determination of the fundamental oscillation frequency is performed through specifying, as a harmonic oscillation series group, a group of peak frequencies containing at least two peak frequencies, in which an interval between zero (0) and first peak frequencies, an interval between first and second peak frequencies, . . . , and an interval between (n-1)th and nth peak frequencies (where n is a natural number) are equal to each other, from among the peak frequencies in the spectrum components, to carry out the method based on the peak frequencies in the specified harmonic oscillation series group.

Description

technical field [0001] The present invention relates to a method for manufacturing an optical fiber, and more particularly, to a method for accurately and stably measuring tension in optical fiber drawing. Background technique [0002] Generally, when manufacturing an optical fiber, the optical fiber substrate is heated and melted from the lower end, and then the molten deformed portion is extended into a linear shape. In addition, the surface of the optical fiber obtained after heat-stretching is covered with a thermosetting resin, an ultraviolet-curing resin, or the like. In such a heating and drawing method, the production of optical fibers is generally called 'drawing'. [0003] In the case of drawing an optical fiber base material to obtain an optical fiber, if the tension during drawing is not controlled, the transmission characteristics of the optical fiber, especially the transmission loss, will vary in the longitudinal direction, so it is necessary to manage it so ...

AI Technical Summary

Problems solved by technology

[0014] However, the techniques disclosed in U.S. Patent No. 5,079,433 and JP-A-10-316446 are used when the noise is the fundamental vibration frequency of the optical fiber or a vibration frequency close to an integer multiple thereof, and when there is a noise peak within the peak search range. , there is a risk of incorrect determination of the fundamental vibration frequency

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