High peak power eye-safe coherent EYDFA laser source

Abstract

Coherent Laser Radar is a powerful remote sensing tool, which can be applied to range-finding, target discrimination, vibrometric monitoring, air pollution monitoring, aircraft wake-vortex and clear-air turbulence analysis. A high power, highly efficient, near diffraction limited and highly reliable pulsed coherent laser source is a key sub-system required in a coherent Lidar sensor. When humans are involved, eye safe laser emission is also typically required. Therefore a highly efficient fiber laser system based on a coherent Master-Oscillator followed by a chain of Erbium (EDFA) and Erbium co-doped with Ytterbium fiber amplifiers (EYDFA) is ideally suited for this application suite. In this paper, we are presenting an all polarization-maintaining fiber architecture and experimental results on such a high peak power fiber laser system allowing for versatile modulation strategies at a wavelength of 1563nm commensurate with a clear atmospheric transmission window and eye-safe operation. The system is constituted by three amplification stages, all based on Polarization-Maintaining fiber. With 660ns and 20Kpps, over 500W peak power pulses have been experimentally demonstrated with near diffraction limited performance with this all PM fiber system.