Two-dimensionally controllable DSR generation from dumbbell-shaped mode-locked all-fiber laser*

Abstract

An all-fiber dumbbell-shaped dual-amplifier mode-locked Er-doped laser that can function in dissipative soliton resonance (DSR) regime is demonstrated. A nonlinear optical loop mirror (NOLM) and a nonlinear amplifying loop mirror (NALM) are employed to initiate the mode-locking pulses. Unlike conventional single-amplifier structure, the output peak power of which remains unchanged when pump power is varied, the proposed structure allows its output peak power to be tuned by changing the pump power of the two amplifiers while the pulse duration is directly determined by the amplifier of nonlinear amplifying loop mirror. The entire distribution maps of peak power and pulse duration clearly demonstrate that the two amplifiers are related to each other, and they supply directly a guideline for designing tunable peak power DSR fiber laser. Pulse width can change from 800 ps to 2.6 ns and peak power varies from 13 W to 27 W. To the best of our knowledge, the peak power tunable DSR pulse is observed for the first time in dumbbell-shaped Er-doped all-fiber mode-locked lasers.