Megawatt peak power from a Mamyshev oscillator
Historically, it has been really tough to make an ultrafast fiber laser that is both environmentally stable and that has good performance (i.e., it has similar performance as a Ti:sapphire oscillator). Recently, several groups have realized that a pair of spectral filters, each offset from the center of the laser gain spectrum, can be used as an effective saturable absorber. An intense pulse will experience nonlinear spectral broadening within fiber in between the filters, and can oscillate stably in a ring cavity formed in this way – a laser we call a ‘Mamyshev oscillator’ (see figure). Low-intensity pulses, or continuous-wave lasing, are meanwhile strongly attenuated. This mechanism, first proposed by Pavel Mamyshev for signal regeneration in telecommunications, is fully compatible with environmentally-stable laser designs. In this paper, we show that the Mamyshev oscillator can, when combined with the self-similar evolution of parabolic pulses, actually support extraordinary performance. Our initial experiments already show 10 times higher peak power than the previous state-of-the-art, and we are optimistic about further improvements.