Tunable and Switchable Narrow Bandwidth Semiconductor-Saturable Absorber Mirror Mode-Locked Yb-Doped Fiber Laser Delivering Different Pulse Widths

The wavelength-tunable and switchable narrow bandwidth mode-locking operation is demonstrated in an all fiber laser based on semiconductor-saturable absorber mirror (SESAM). Two narrow-band fiber Bragg gratings centered at 1029.9 nm and 1032 nm respectively with a polarization controller inserted between them are used to realize the wavelength switchable between 1029.9 nm and 1032 nm. The laser delivers different pulse widths of 7.5 ps for 1030 nm and 20 ps for 1032 nm. The maximum output power for both could reach ~6.5 mW at single pulse operation. The output wavelength could be tuned to about 0.9 nm intervals ranging from 1030.2 nm to 1031.1 nm and from 1032.15 nm to 1033.7 nm with the temperature change of the fiber Bragg grating, respectively.