METHOD FOR THE MEASUREMENT OF THE DIAMETER OF A GLASS FIBER USING THE RESONANT BACKSCATTER TECHNIQUE AND MEASURING APPARATUS FOR CARRYING OUT THE METHOD

摘要

Method for the measurement of the diameter of a glass fibre using the resonant backscatter technique during the application of which the fiber to be measured is illuminated by a tunable wavelength laser and the extrema of the detected intensity of the rays backscattered from the fiber into a small solid angle are registered while tuning the laser wavelength. The paths of the illuminating and backscattered rays are separated. The illuminating laser beam of the measuring arrangement suitable for carrying out the method subtends a small angle with the normal of the fiber axis and the intensity detector that receives the backscattered rays is placed so that the principal direction of the rays accepted by it makes an angle of the same size but opposite sign with the said normal. Before the detector there is a slit of a size corresponding to the said small solid angle.