Linearly-polarized short-pulse AOM Q-switched 978 nm photonic crystal fiber laser.

A linearly-polarized, high peak power, short-pulse, Q-switching Yb-doped large-mode-area photonic crystal fiber (PCF) oscillator with three-level system operation is demonstrated. By optimizing cavity parameters and adopting linear polarization component, the laser can easily obtain linearly-polarized output over 2 W at 978 nm with polarization extinction ratio (PER) up to 43 dB without any additional wavelength filter. Less than 50 ns stable output pulses are achieved within repetition range of 10 kHz-200 kHz and short pulse of 9 ns pulse duration, 130 kW peak power at 10 kHz can be reached. The characteristics and the key issues of the laser, such as interpulse ASE, spectrum ASE around 1030 nm, are with detailed discussion in the paper.