High energy pulsed eye-safe fiber amplifier

Eye-safe pulsed laser sources are needed for remote sensing applications such as range finding and active imaging. Er-doped fiber-based sources combine the benefits of efficient direct eye-safe operation and reliability through monolithic fiber assemblies. The reported energy per pulse has been limited in the past to less than 2 mJ for various configurations. More recently, the authors have shown that up to 11 mJ could be extracted at 1 kHz using a multimode Er-doped fiber in a Q-switched laser configuration. In this work, the authors report on new fibers characterization in a MOPA (master oscillator power amplifier) arrangement, and demonstrate up to 17 mJ energy at 1 kHz (11 mJ at 5 kHz), with hundreds of nanosecond pulses and a suitable beam quality.