Generation of Dissipative Soliton Resonance Pulse in 2 um All-Polarization-Maintaining Mode-Locked Fiber Laser

The dissipative soliton resonance (DSR) pulses are demonstrated experimentally in an all polarization-maintaining (PM) thulium-doped mode-locked fiber laser. The mode-locked operation is achieved by using of the nonlinear amplifying loop mirror mechanism (NALM). Each loop of the apparatus includes an independently controlled amplifier and a section of gain fiber. The experiment is carried out in central wavelength of 1969.8 nm and 3.5 ns as the maximum output pulse width. Single pulse energy increases from 5 to 10 nJ with the enhancement of amplifier power A
₂
, when amplifier power A
₁
is set to 2 W. In addition, the DSR pulse properties are experimentally verified by changing the length of PM-1950 fiber spliced into the NALM loop. We have achieved environmentally stable mode-locked pulses at 3, 2.1, and 1.62 MHz corresponding to the maximum pulse energies of 6.8, 20 and 29.1 nJ. The output pulse is stable and robust at different states.