Abstract

We report the generation of pulses with τ≳ 100fsec duration between 1.55 and 1.85μm in a fiber pumped by a color center laser. Working in the anomalous group velocity dispersion regime of fibers, several groups [1,2] have generated short pulses with extremely broad bandwidth, which they attribute to stimulated Raman scattering. The mystery in all these experiments is that the spectral width is almost ten times the expected band width for the measured pulses, yet the pulses do not show coherence spikes. We describe a model of the spectrum as originating from modulation instability (MI)[3,4] and soliton self-frequency shift (SSFS)[5] effects, and the broad band width as being an ensemble average over solitons which frequency shift by different amounts. Cross-correlation measurements verify the lack of correlation between different parts of the output spectrum.

© 1989 Optical Society of America