Study On Power-scaling Of High-power Tm-doped Fiber Laser

Compared with the fiber laser operating at 1 ?m,2 ?m fiber laser has various advantages including higher nonlinear effect threshold,easier to be held in single-mode state and eye-safety.Recently,with the development of fiber laser technology,2 ?m high-power fiber laser has achieved rapid progress and applied on the fields like industril processing,biological medicine,co?munication and remote sensing.However,power-scaling of 2 ?m fiber laser is still faced with many challenges,such as pumping brightness,thermal load,nonlinear effects and maximum extractable power,which confine further improvement of output power.Therefore,we study the power-scaling of high-power Tm-doped fiber laser theoretically and experimentally.This dissertation reviews the progress of high-power continuous-wave,pulsed fiber laser and superfluorescence operating at 2 ?m.We analyze and conclude the limitations of Tm-and Ho-doped fiber laser power-scaling,and investigate the impact of pumping brightness,thermal load and nonlinear effects in theory and experiment.For the limitation of pumping brightness and thermal load,various pumping schemes of high-power Tm-doped fiber laser are theoretically investigated.We analyze and compare pumping schemes of Tm-doped fiber laser,and model the ³H₆?³F₄ pumping scheme.According to the simulated system efficiency and potential maximum incident pump power of 0.79 ?m LD and 1.9 ?m Tm-doped fiber laser pumping schemes,employing 1.9 ?m Tm-doped fiber laser pumping scheme is the best choice to achieve higher output power.For the limitation of nonlinear effects and power-scaling which result from temporal stability,the power-scaling of Tm-doped fiber-based superfluorescent sources are experimentally investigated.We theoretically calculate how the temporal stability of master oscillator impact on the threshold of nonlinear effects and power-scaling in MOPA system.Then we build a fiber-based superfluorescent source with good temporal stability,and realize power-scaling exceeding 300 W.The influence of different linewidth on power-scaling is also researched.Considering the applications of 2 ?m fiber laser,we also experimentally study the 2 ?m fiber lasers with unique temporal and spectral characteristics.We build a mode-locked Tm-doped fiber laser based on disspative soliton resonance effect by fiber dispersion management technique,and realize 2 ?m rectangular pulses emission at anomalous dispersion.And a high-power Tm-doped fiber laser operating at 2153 nm with the maximum output power of 12 W is built,which verify the feasibility of high-power Tm-doped fiber laser operating at the edge of gain-spectrum.The amplifier scheme of long-wavelength Tm-doped fiber laser is also discussed.