Generation of sub-100 fs pulses from a SESAM-NPE hybrid mode-locked Yb-doped fiber laser at a fundamental repetition rate of 1.15 GHz

Abstract

Supercontinuum generation via direct pumping of unamplified high-repetition-rate, sub-100 fs pulses with a pulse energy lower than 50 pJ is superior in noise performance and features a high acquisition speed. We demonstrate a novel, to the best of our knowledge, gigahertz-repetition-rate, mode-locked Yb-doped fiber laser, where the hybrid mode-locking approach is employed. The laser has a low initiating threshold of 300 mW and a broad mode-locking range of 600 mW (300–900 mW) in terms of pump power. The shortest obtained pulse width of the laser after compression is 95 fs, and the highest output pulse energy is 92.9 pJ at a fundamental repetition rate of 1.15 GHz. Moreover, the laser’s output polarization states are switchable, and it has a polarization extinction ratio of 17.9 dB.