All-Normal-Dispersion Dissipative Soliton Ytterbium Fiber Laser Without Dispersion Compensation and Additional Filter

We report on the generation of mode-locked dissipative soliton pulse from an all-fiber ytterbium-doped fiber laser based on nonlinear polarization rotation without dispersion compensation or an additional filter. The formation of the dissipative soliton pulse is a self-consistent result of various effects in the laser cavity, including positive fiber dispersion, nonlinearity, cavity transmission, and gain saturation and narrowing over one cavity round trip. Stable mode-locked pulses with pulse energy of 1.1 nJ have been achieved, which is restricted by the available pump power. For comparison, an all-normal-dispersion fiber laser with filter is also constructed by simply incorporating a section of polarization-maintaining fiber. The results indicate that the dissipative laser without a filter has a simpler configuration but better performance such as broader spectral bandwidth and resistance to the multiple pulse state. The operation of the dissipative soliton lasers without an additional filter has been numerically simulated, which confirms the experimental results.