Passively Q-switched 0.24 mJ ring laser based on anisotropic tapered fiber

We report on a passively high-power Q-switched ring laser based on the active polarization-maintaining double-clad tapered Yb3+-doped fiber (APM-T-DCF) as gain media. It generates 0.24 mJ pulse trains which consist of Q-switched pulses each with the energy of about 48 µJ and up to 385 W of peak power. Q-switched regime was achieved by tuning the optical feedback polarization state and band pass filtering. For the best of our knowledge, for the first time, we demonstrate Q-switched fiber ring laser based on APM-T-DCF.