Pulse separating in transmission characteristics of multimode graded index optical fibers.

The transmission characteristics of multimode graded index optical fibers, whose refractive index profiles were nearly parabolas, were measured. No change of the output pulse waveform could be detected at a 1-km length with a lowest-order mode excitation. In the case of mismatching excitation, output pulse waveforms separated into two pulse peaks. This was caused by the refractive index profile that was not a single function but a combination of two functions.