Product Code: ICAL06_1305

High Average Power, Low Non-linearity Ytterbium Fiber Amplifier using Spectral Compression
Authors:
Yoann Zaouter, Amplitude Systemes; Pessac France
Eric Cormier, University of Bordeaux; Talence France
Pierre Rigail, Amplitude Systemes; Pessac France
Clemens Hoenninger, Amplitude Systemes; Pessac France
Eric Mottay, Amplitude Systemes; Pessac France
Presented at ICALEO 2006

High precision applications, such as micro and nano-machining, waveguide writing, nano-structuring require both moderate energy level, and high average power. We present a high average power fibre amplifier. We report on a Ytterbium doped fiber-based amplifier, delivering up to 30W average power with an energy per pulse of 10µJ. We achieve almost- transform-limited pulses of ~10-ps duration by phase-modulation-induced spectral compression. The setup consists in a high repetition rate bulk femtosecond oscillator delivering up to 150 nJ at 10MHz, negatively chirped in a grating-based stretcher. Its repetition rate is then reduced to 3MHz by a pulse picker. The 10-ps stretched pulses are then amplified in a truly single mode rod-type fiber which exhibits a mode-field diameter of about 1500 µm². The fiber amplifier is directly diode-pumped at 976 nm. Up to 50W are launched into the amplifing media resulting in 30W average output-power at 3 MHz. Furthermore, the spectral broadness was reduced down to 0.5 nm, making the system optimum for frequency conversion, including second and third harmonic generation.