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 ³ H ₅ . To the best of our knowledge, this is the first study that revealed that level ³ H ₅ plays an essential role in reinitialization, achieving sequential pulses, and limiting the maximum repetition rate.