Mode-locked pulsed fiber array scalable to high power

We have developed and demonstrated a fiber amplifier based architecture capable of high peak power pulsed operation that is scalable to high average powers ⪆10 kW. Our approach uses a mode-locked master oscillator to provide the short pulse waveform and an array of fiber amplifiers to provide high efficiency power amplification using a coherently phased, wavelength multiplexed approach. The mode-locked oscillator input is decomposed into its individual modes using a grating, the individual wavelengths are then amplified in a CW format in the fiber amplifier array, recombined with a second grating, and phased to reproduce a high peak power, short pulsewidth, mode-locked output train. We report the initial demonstration of this architecture with an array of 4 fiber amplifiers. 4 modes of the master oscillator output were selected and amplified from 1 mW to 1 Watt each, followed by recombination and phasing. The phased output pulse train effectively reproduced the master oscillator pulse shape, providing a mode-locked output train of 50 psec pulses. The phase control is performed in parallel for each element of the amplifier array and is directly scalable to high average powers by increasing the power of the individual amplifiers and increasing the size of the amplifier array.