Coherent combining efficiency in strongly saturated divided-pulse amplification systems.

ABSTRACT

Numerical simulations are performed to analyze effects that limit the combining efficiency in divided-pulse amplification setups. The model allows us to evaluate the impact of self- and cross-phase modulation between pulse replicas, Kramers-Krönig-related phase shifts, and inter- and intra-replica saturation effects. In particular, we show that when the energy per replica approaches the saturation energy, pulse reshaping induced by the gain saturation coupled with self-phase modulation imparts a temporal differential phase that decreases the combining efficiency. This effect limits the energy that can be extracted by a single replica, thereby providing design rules to scale the performances of short pulse laser sources using this technique.