Fiber Laser Beam Combining

In Phase-I of this work, a steady state model incorporating the most important nonlinear effects was successfully developed to analyze passive phasing of fiber amplifier arrays. This work showed a technique of reverse pumping to mitigate Four-Wave Mixing (FWM) and Cross-Phase Modulation (XPM) in fiber amplifiers. In Phase II we propose to extend the modeling developed in Phase-I to include time-dependent dynamic effects to understand observed stability and mode-locking phenomena. We propose to employ the two 1kW fiber amplifiers at the Albuquerque Northrop Grumman site to validate theoretical predictions of this work. The modeling effort should provide better understanding and assessment of passive phasing fiber systems and help in improving the performance of these systems. BENEFIT: The Air Force Research Laboratory (AFRL) has been in the forefront of combining lasers for power scaling of solid state lasers including diode lasers (PILOT program) and currently fiber lasers. Currently, there are several promising approaches for fiber laser combining, with each having advantages and disadvantages. Some are more suited for certain applications than others. Modeling rooted in experimental work is essential to gain clarity in sorting out the different approaches with their ideal applications. Libration Systems will commercialize the software developed under this SBIR for sale to Government and industry for work in fiber lasers.