Wavelength tunable self-mode locking semiconductor disk laser

Abstract

Ultrashort pulse lasers are widely used in laser spectroscopy, microwave measurements, high-speed sampling, medical diagnostics, communication systems, and many other fields. This work presents a tunable self-mode-locked semiconductor disk laser, which is based on the combination of the Kerr effect in the gain chip and the soft aperture formed by the overlap of pumping and laser spot. A linear resonator with a length of 93 mm is formed by the high reflectivity distributed Bragg reflector at the bottom of the gain chip and the external output coupler with 100 mm curvature radium. The mode-locking can be started by fine-tuning the size of the pump spot and the length of the resonator, and a stable self-mode-locked output can be achieved at 980 nm wavelength. Then, a thickness of 2 mm birefringent filter is inserted into the resonator at Brewster angle, and a continuous tuning of 37 nm wavelength was obtained by rotating the filter. The repetition rate of achieved stable mode-locked pulse train at 980 nm is 1.6 GHz, the pulse width is 4.3 ps, the maximum output power is 467 mW, and the corresponding peak power is 68 W.