David M. Beaverton Hemenway

Tandem photonic amplifier employing a pulsed master oscillator fiber power amplifier with programmable temporal pulse shape capability

We report on recent advances in the development of a 1064 nm pulsed master oscillator fiber power amplifier (MOFPA) with integrated modulators enabling programmable temporal pulse shapes and its employment in a tandem photonic amplifier. The MOFPA amplifier chain is seeded by a laser diode operated in the CW regime, yielding very stable spectral characteristics that are independent of the pulse repetition rate and pulse shape. The use of 3 GHz integrated LiNbO3 electro-optic modulators in conjunction with high speed digital electronics results in an excellent pulse shaping capability, a fine pulse amplitude stability and high repetition rate operation (100 kHz-1MHz) with fast rise times (<1ns). Energy per pulse of 8-10 μJ with good beam quality characteristics are obtained using advanced large mode area (LMA) fiber designs in the final power amplifier stage. The output is linearly polarized with a spectral bandwidth of < 0.1 nm. When employed in a tandem amplifier configuration, in which the MOFPA output is input to a single-stage, single-pass Nd:YVO4 amplifier pumped by a single 30 W fiber-coupled 808 nm diode, a 600 mW average power at 100 KHz signal input from the MOFPA was amplified to 6 W with faithful amplification of the input temporal pulse profile while achieving excellent beam quality (M2<1.1) and pulse amplitude stability (< ±3%, 3σ). A model of tandem amplifier performance shows good agreement with experimental results and indicates prospective performance of advanced tandem photonic amplifier configurations.

355 nm Tailored Pulse Tandem Amplifier

We report on a 355 nm tailored pulse tandem amplifier. 1064 nm tailored pulse fiber laser output was amplified in a diode-pumped Nd:vanadate amplifier and then frequency converted to produce 0.6 W at 100 KHz.