Simulation for efficiency improvement of a thuilium Q-switched ytterbium-doped all-fiber laser

We theoretically explore the mechanism in a thulium Q-switched ytterbium-doped all-fiber fiber laser using a set of rate equations to model the correlations between the photons and the five energy levels of thulium involved in the Q switching mechanism. We demonstrate that by coupling with a gain-switched resonator, the Q-switched laser is stabilized up to the maximum pulsing rate that is limited by the lifetime of level ³H₅. To the best of our knowledge, this is the first study that revealed that level ³H₅ plays an essential role in reinitialization, achieving sequential pulses, and limiting the maximum repetition rate.