107-kW-Peak-Power 2-ns Pulse Tapered Er-doped Fiber Amplifier

A novel tapered Er3+-doped fiber design for high peak power amplification has been developed and tested. The core diameter was changing along 2.5 meters from 22.5 μm (single-mode operation) to 86 μm. Amplification of 2 ns pulses has resulted in peak power of 105 kW (0.25 mJ) with nearly diffraction-limited beam quality (M2<;1.27).