Generation of picosecond pulses directly from a 100 W, burst-mode, doping-managed Yb-doped fiber amplifier

Abstract

Burst-mode laser systems offer increased effectiveness in material processing while requiring lower individual pulse energies. Fiber amplifiers operating in this regime generate low powers in the order of 1 W. We present a Yb-doped fiber amplifier, utilizing doping management, that scales the average power up to 100 W. The laser system produces bursts at 1 MHz, where each burst comprises 10 pulses with 10 μJ energy per pulse and is separated in time by 10 ns. The high-burst repetition rate allows substantial simplification of the setup over previous demonstrations of burst-mode operation in fiber lasers. The total energy in each burst is 100 μJ and the average power achieved within the burst is 1 kW. The pulse evolution in the final stage of amplification is initiated as self-similar amplification, which is quickly altered as the pulse spectrum exceeds the gain bandwidth. By prechirping the pulses launched into the amplifier, 17 ps long pulses are generated without using external pulse compression. The peak power of the pulses is ∼0.6 MW.

Sub-Microsecond Pulsed Pumping as a Means of Suppressing Amplified Spontaneous Emission in Tandem Pumped Fiber Amplifiers

“…This has been shown to improve the speed of material processing compared to the same energy delivered in an evenly spaced pulse train [15]. This mode of operation also has scientific uses such as for photo-injectors in large free-electron systems [16] and has been successfully demonstrated in high performance fiber laser systems [17]. For our chosen example of 70 ns signal pulses at 10 kHz repetition rate a picosecond pulse burst could be comprised of 700 x 10 µJ pulses sliced from a 10 GHz pulse train (100 ps pulse spacing).…”

50-W, 1.6-GHz pulse repetition rate from a burst-mode Yb-doped fiber laser

“…Ultra-short fiber lasers operating in the burst-mode have developed more rapidly in the past decade [1,2]. They are drawing much interest due to their significant advantages in material processing, especially in high precision thermal-damage free ablation.…”

All-fiber, high-power, picosecond Yb double clad tapered fiber amplifier

“…The available systems are, however, free-space constructions typically using massive rod-type fibers. Compact, all-fiber Vb-doped picosecond lasers producing high peak and average powers were recently reported [1,2]. They employ doping management in order to decrease thermal load and impact of nonlinear effects.…”