Calculation of bandwidth from index profiles of optical fibers 2: Experiment

The impulse response and bandwidth of GeO(2)-doped and B(2)O(3)-doped multimode optical fibers are calculated from their measured refractive index profiles. The computational method is based on the WKB solution of the guided mode problem in which the pulse delay time of each mode is determined with profile dispersion being taken into account. Accurate profiles are obtained by a newly developed focusing technique, which allows measurements to be made on whole-fiber samples. The predicted bandwidths of the GeO(2)-doped fibers range from approximately 200 to 1200 MHz-km and are in good agreement with the bandwidths and impulse responses previously measured by frequency-domain and time-domain optical shuttle pulse techniques on kilometer lengths of the fibers.