CW mode-locked fiber laser by improved all-polarization-maintaining figure-9 cavity at 1064 nm

In order to realize broadband continuous wave (CW) mode locking by figure-9 fiber laser at 1064 nm, we propose an improved all-polarization-maintaining figure-9 cavity structure by adding gain fiber to both the loop and the linear arm in the laser. When the two sections of gain fiber are pumped simultaneously, the CW mode locking regime can be obtained. In this work, noise-like mode-locked pulses are generated with a central wavelength of 1064 nm and a chirped fiber grating (CFBG) is used for dispersion management. The net dispersion of the cavity is about 0.01 ps2 and the output power is 234 mW. The noise-like pulses are validated by autocorrelator, the peak duration on the autocorrelation trace pedestal is about 261 fs, and the pedestal duration is about 103 ps. Numerical simulations are performed on the noise-like pulses, which agree with the experimental results. This study has inspiration for mode-locked lasers with a central wavelength of 1064 nm, and has potential application value in fields such as supercontinuum generation, fiber sensing, laser microfabrication, and laser ablation.