Ultrafast Soliton Dynamics in an All-Fiber Thulium-Doped Energy-Managed Soliton Fiber Laser

This paper presents a novel 2 μm all-fiber ring laser based on energy management mechanism. The laser achieves energy-managed mode locking by adjusting the pump power, filter central wavelength, and polarization controllers. At 1.3 W pump power, stable soliton can be generated with spectral range of 30 nm, average power of 30 mW, pulse duration of 1.5 ps, and single pulse energy of 3.9 nJ. The pulses have a smooth spectrum without Gordon-Kelly sidebands. By further increasing the pump power and tuning the polarization controllers, multiple pulse patterns are also obtained such as soliton molecules, soliton molecules pulsation and noise-like pulses. Spectral evolutions of these patterns are measured by time-stretch Fourier dispersive transform technique, utilizing two fiber Bragg gratings as dispersion element. The numerical model is also established to reveal the intracavity soliton dynamics. Our work might benefit the development of 2 &μm ultrafast light source, as well as the fundamental understanding of nonlinear physics.