Cross-phase modulation in a semiconductor laser amplifier determined by a dispersive technique

Cross-phase modulation in a semiconductor laser diode amplifier is reported. A simple expression for the chirp imparted on a weak signal pulse by the action of a strong pump pulse is derived. A novel dispersive technique for characterizing the resulting nonlinear chirp is introduced and used in the present experiment. A maximum frequency excursion of 16 GHz, due to the cross-phase modulation, was measured. A value of 6 was found for alpha /sub xpm/, which is a factor for characterizing the cross-phase modulation in a similar manner to the conventional linewidth enhancement factor alpha .<
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