LIMITS ON AMPLIFICATION OF PICOSECOND PULSES BY USING SEMICONDUCTOR-LASER TRAVELING-WAVE AMPLIFIERS

Abstract

The limiting factors in picosecond pulse amplification by semiconductor traveling-wave laser amplifiers are investigated, including the effects of the spontaneous emission. For the amplifier with a negligible amount of spontaneous emission, amplification is limited by the energy saturation for low-repetition-rate pulses, while the power saturation is the limiting factor for high-repetition-rate pulses. The spontaneous emission decreases both the signal gain of the amplifier and the signal-to-noise ratio considerably. The effective gain recovery time and the effective saturation energy are strong functions of the input pulse energy and the amount of the spontaneous emission.