Low-Threshold Broadband Pulse Generation in an All-Fiber Hybrid Mode-Locked Laser

Mode-locked fiber lasers that can generate femtosecond pulses can find applications in many areas from high-resolution imaging to high-precision measurement. Bandwidth of their output is one of the most important performance parameters. Prior schemes often require more complicated setup or high pump powers, while a simpler laser setup at a lower pump power with a broadband output is more desired. By combining the low-threshold, easily self-starting properties of nonlinear mode-lockers and the pulse-shaping capabilities of the nonlinear polarization rotation effect in the laser, broadband pulses with a 71 nm bandwidth are generated from an all-fiber Erbium fiber laser at a pump power as low as 47.7 mW. Compared to other broadband mode-locked fiber lasers, the pump power requirement is significantly reduced. Our research shows promise in low-cost and power-efficient laser sources for many potential applications.