Changes in the diameter of a fiber are determined by directing a laser beam transversely onto the fiber and directing a fringe produced by the scattering of the beam to a photodiode array by means of a transforming lens. Circuitry is provided to detect movement of the fringe on the diode array thereby...http://www.google.com/patents/US4650322?utm_source=gb-gplus-sharePatent US4650322 - Method and means for high resolution measurement of fiber diameter
