Mode-locked operation of a master oscillator power amplifier

We report the first mode-locked operation of a tapered amplifier MOPA to generate short optical pulses with record high average powers and pulse energies. The MOPA is constructed using a discrete semiconductor oscillator and amplifier operating at 940 mm wavelength. Pulses of 4.2 ps duration are generated with average powers of 296 mW and peak powers of 28.1 W. The energy of these pulses was 118 pJ, corresponding to energies more than an order magnitude greater than the gain saturation energy in the mode-locked laser itself, and also corresponds to energies internal in the amplifier in excess of the gain saturation energy. Although the amplifier saturation energy limits the pulse energy obtainable in a mode-locked laser, the MOPA configuration demonstrates that generation of pulses with energies in excess of the amplifier saturation energy is feasible in a post-amplification stage.<
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