Limits on amplification of picosecond pulses by using semiconductor laser traveling-wave amplifiers

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.<
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