Application of the backscattering technique to the determination of parameter fluctuations in multimode optical fibers

An experimental study of backscattering traces from fibers with random variations of core diameter and numerical aperture has been carried out. The "mode-filtering" technique, which is employed in the measurements, is shown to be a powerful means of separating the parameter fluctuation effects from the actual exponential power decay. The experimental results are then found to be in excellent agreement with the predictions of a recent backscattering theory. It is shown that backscattering measurements can easily be used to place upper limits on the magnitudes of parameter fluctuations in present day fibers.