Passively Q-switched and Mode-locked All-fiber Yb-doped Laser with β-InSe Saturable Absorber (Invited)

A stable Q-switched and mode-locked Ytterbium Doped Fiber Laser (YDFL) based on layered semiconductor beta-InSe as Saturable Absorber (SA) were demonstrated for the first time. The modulation depth and non-saturable absorbance of the SA were 47% and 20%, respectively. After inserting the SA into YDFL, the stable Q-switched pulse operation can be easily obtained with the repetition rate range from 53.42 kHz to 217 kHz. The minimum pulse duration was 630 ns and the maximum single pulse energy was 47.9 nJ. By optimizing the laser resonator, a stable mode-locking pulse with repetition rate of 10.82 MHz, maximum output power of 51.2 mW and maximum single pulse energy of 4.7 nJ can be achieved. The experimental results demonstrated that beta-InSe SA has great potential in near infrared ultrafast nonlinear optical.