1.6 μm band mode-locked fiber laser

In order to obtain the 1.6 μm-band mode-locked pulse based on the soliton self-frequency shift effect, an erbium-doped fiber laser with nonlinear polarization rotation is designed, whose pulse is detected by a dual-output structure. At a pump power of 350 mW, the noise-like pulses with the central wavelength of 1560 nm are detected at the two outputs at the same time by properly adjusting the polarization controller. The 3 dB bandwidth is 17.5 nm, and the pulse duration is 968 fs. When the pump power is further increased to 550 mW, and the 1-port noise-like pulse remains fixed, the central wavelength of the 2-port noise-like pulse redshifts to 1614 nm, the 3 dB bandwidth increases to 64.4 nm, and the pulse duration decreases to 302 fs. The maximum output power of the resonant cavity is 11.4 mW. The experiment also analyzes the influence of the length of dispersion shifted fiber on soliton self-frequency shift. The results show that within a certain range, as the length of the dispersion shifted fiber increases, the frequency shift distance of the soliton self-frequency shift decreases. This 1.6-μm band fiber laser has potential applications in the field of optical communications.