Femtosecond Mamyshev fiber oscillator started by a passively Q-switched microchip laser

A femtosecond Mamyshev fiber oscillator in normal dispersion mode at 1 mu m was started reliably and safely by an inexpensive diode-pumped passively Q-switched monolithic microchip laser emitting 300-ps pulses. Four-wave mixing spectral broadening is shown to play a pivotal role in starting the Mamyshev oscillator, owing to the random short and intense temporal fluctuations allowed by its similar to 10-nm bandwidth. Systematic studies of the starting dynamics show that a success rate of 100% of the attempts is achieved with modest seed energy, as low as similar to 30 nJ from the sub-nanosecond laser, corresponding to similar to 100 pJ for the total four-wave mixing signal required to start the oscillation. (C) 2022 Optica Publishing Group