CHARACTERIZATION OF THE OPTICAL-FIBER DRAWING PROCESS

Optical fibres, together with light sources and detectors, play a key role in telecommunication systems. One of the factors affecting the tr ansmission losses of the fibre and its tensile strength, is the diamet er uniformity which is directly related to the drawing process. A high degree of diameter uniformity in the fibre drawing process is achieve d by an appropriate construction of the drawing machine and by applyin g an optimal system for the control of the diameter. Optimisation of s uch a control requires prior structural identification of the drawing process and its parameters. In this work, a nonparametric characterisa tion of the drawing process has been made, based on a priori informati on obtained by mathematical modelling and simulation. The cross correl ation method has been used, with a random noise as the input signal. T he transfer function obtained is a second order one with real poles, w hich accords well with the theoretical assumptions. Identification of the drawing mechanism and fibre diameter measurement system, which con tains a significant dead time, has also been made. The results obtaine d can be used for the synthesis of the optimal control function.