Resolving the Buildup Dynamics of Noise-like Pulse in Mamyshev Oscillator

The Mamyshev oscillator (MO) operating in the noise like pulse (NLP) regime can produce laser pulses with broad bandwidth and high pulse energy, which is crucial for many applications in optical communication, supercontinuum generation and micromachining. However, experimentally verifying the buildup dynamics of NLP in MO remains a significant challenge. Here, the all-fiberized ytterbium-doped MO has been designed to deliver NLP with 3-dB bandwidth exceeding 140 nm experimentally, and the buildup dynamics of NLP in the MO has been characterized by the time-stretch dispersive Fourier transform (TS-DFT) technique. Unlike the NLPs from conventional mode-locked fiber laser, the generation of NLP in MO is from the survived seed pulse in MO, and the transition from external seed pulses to stable NLP operation in MO involves four ultrafast phases, including seed pulse injection, amplified seed pulse, NLP generation, and stable NLP state. The numerical simulation results further validate the NLP buildup mechanisms in MO. The results can deepen the understanding of the NLP operation in MO, and may support the generation and manipulation of the pulse dynamics in MO.