ULTRASHORT-PULSE RESHAPING USING A SEMICONDUCTOR-LASER AMPLIFIER IN ARING CAVITY

We describe an interferometric method for the reshaping and amplificat ion of a mode-locked train of short laser pulses, based on a ring cavi ty containing a semiconductor laser amplifier. The amplifying medium p rovides both the gain and the phase nonlinearity needed for pulse resh aping. Numerical simulations have shown that the best reshaping occurs with the use of a low finesse cavity operated at laser threshold. Upo n these conditions, calculations have shown that both pulse compressio n and amplification are obtained over a broad range of values of the l inear phase shift between the cavity and pulse train. Pulse amplificat ion and compression factors exceeding 50 and 100, respectively, result ing in peak power amplification factors up to 1000, are predicted for a 25 dB amplifier. These factors can be increased by decreasing the ra tio of the input pulse energy over the saturation energy of the amplif ier.