NONLINEAR-OPTICAL COMPRESSION OF ER3-FIBER AMPLIFIED 1.5-MU-M LASER-DIODE PULSES()

Femtosecond optical pulses of 110-200-fs width have been produced usin g a gain-switched distributed-feedback semiconductor laser followed su ccessively by a linear compression stage and a nonlinear compression s tage. Analyzes are focused on this last stage where pulses with peak p owers corresponding to 10- and 12-order solitons are fed at fiber inpu t end. Experimental results are web described using both the modified nonlinear Schrodinger equation and an accurate intensity and phase mod el of the gain-switched laser diode. Experiments are shown to be corre ctly described only if both intrapulse stimulated Raman scattering and third-order dispersion are taken into account. Guidelines are then gi ven to optimize the nonlinear fiber compression using laser diodes and fiber amplifiers. The influence of the third-order dispersion in fibe r compressor is first evaluated. Second, the nonlinear self-phase modu lation induced in the fiber amplifier is studied. It is shown to be th e main factor limiting any further pulse shortening with this techniqu e.