title: Multistage Yb-doped fiber amplifier generating megawatt peak-power, subnanosecond pulses.
abstract: A Q-switched microchip laser generating 1064 nm wavelength, subnanosecond pulses at a 13.4 kHz repetition rate was used to seed a dual-stage amplifier featuring a 40 microm core Yb-doped photonic-crystal fiber (PCF) as the power amplifier. From this source, we obtained diffraction-limited (M2 = 1.05), approximately 450 ps pulses of energy > 0.7 mJ, peak power in excess of 1.5 MW, and an average power of approximately 9.5 W. By further amplifying the PCF output in a multimode 140 microm core Yb-doped fiber, we generated a peak power in excess of 4.5 MW, the highest obtained in a fiber source to our knowledge.
authors.affiliation: Aculight Corporation, 11805 North Creek Parkway South, Bothell, Washington 98011, USA. fabio.diteodoro@aculight.com
authors.forename: Fabio
authors.initials: F
authors.lastname: Di Teodoro
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Brooks