Mamyshev oscillation self-starting mode-locked fiber laser based on a self-feedback amplifying sub-cavity

The Mamyshev oscillator (MO) boasts unparalleled modulation depth advantages in establishing mode-locking. However, this also significantly inhibits the self-starting of mode-locking. This Letter addresses the issue by constructing a self-feedback mechanism for regenerative oscillation. By amplifying noise cycles during the initial pumping phase to introduce periodic fluctuations in light intensity, we successfully achieve self-starting mode-locking at 1550 nm in an MO with a single gain arm structure at the pump power threshold of 76 mW. This self-starting mode-locking mechanism based on self-feedback sub-cavity amplification demonstrates excellent stability and repeatability in a single-arm MO structure. It provides what we believe to be a new approach for developing simple, reliable, and high repetition rate mode-locked lasers.