100 GHz High-Repetition-Rate Vortex Fiber Laser

We propose a 100 GHz high-repetition-rate (HRR) vortex pulse fiber laser based on the dissipative four-wave-mixing (DFWM) mode-locked technique, for the first time to the best of our knowledge. The DFWM mode-locking is realized by combining a Fabry-Perot (F-P) filter with spectral spacing of 0.8 nm and an 85 m long highly nonlinear fiber (HNLF) in the laser cavity. The offset splicing technique and a home-made two-mode chirped fiber Bragg grating (TM-CFBG) are utilized to excite and select the $\mathbf{LP}_{11}$ mode, respectively. The proposed HRR vortex fiber laser is capable of delivering $\pm 1$ order vortex pulses with a repetition-rate of 100 GHz and purity of 82.1%, which may enlarge the application range of vortex beam.