Generation of 39 fs, 3.1 MW Pulses from a Gain-Managed Mode-Locked Fiber Oscillator

Mode-locked fiber oscillators have attracted considerable attention for a variety of practical applications, primarily due to their compactness, robustness and high efficiency. Nevertheless, the generation of high peak power ultrashort pulses remains a major challenge, primarily due to pronounced nonlinear effects and the limited gain bandwidth. Recently, Mamyshev oscillators (MOs) have demonstrated exceptional performance, capable of tolerating accumulated nonlinear phase shifts of up to 60π, thus enabling the generation of sub-50 fs pulses with microjoule-level pulse energies in large-mode area fibers [1], [2]. In this work, we present an all-normal-dispersion fiber oscillator based on nonlinear polarization evolution (NPE), operating within a self-similar gain-managed nonlinear amplification regime. This configuration enables the tolerance of accumulated nonlinear phase shifts comparable to those achieved by MOs. The oscillator directly generates ~200 nJ linearly chirped pulses, which can be externally compressed to ~39 fs, resulting in a peak power of ~3.1 MW.