Patent ID: 6816245
Filing Date: 2004-11-09
Classification: G01L

Abstract:
A method of measuring tension applied to an optical fiber being drawn, which comprises: measuring oscillation of the optical fiber when drawing into the optical fiber; subjecting a waveform of the oscillation to frequency analysis to obtain spectrum components; determining a fundamental oscillation frequency of the optical fiber based on peak frequencies contained in the spectrum components; and converting the fundamental oscillation frequency into the tension applied to the optical fiber being drawn,characterized in that the determination of the fundamental oscillation frequency of the optical fiber is performed through the steps comprising: specifying, as a harmonic oscillation series group, a group of peak frequencies containing at least two peak frequencies, in which an interval between a frequency zero (0) and a first peak frequency, an interval between the first peak frequency and a second peak frequency, . . . , and an interval between an (nâˆ’1)th peak frequency and an nth peak frequency (in which n is a natural number) are equal to each other, from among a plurality of peak frequencies contained in the spectrum components; and determining the fundamental oscillation frequency of the optical fiber based on the respective peak frequencies contained in the specified harmonic oscillation series group.