All-fiber Mamyshev oscillator with high average power and harmonic mode-locking.

In this Letter, we present the first, to the best of our knowledge, experimental demonstration of high-order harmonic mode-locking of an all-fiber Mamyshev oscillator. The laser is entirely realized using standard step-index fiber. It delivers time-stable pulse trains with average powers reaching more than 100 mW at the fundamental mode-locked repetition rate (7.7 MHz) and 1.3 W at the 14th harmonic (107.8 MHz).