Compact integration of amplifier channels for coherent combination of fiber amplifiers

Summary form only given. Coherent combination of fiber amplifiers has become a viable concept for pulse-energy and average-power scaling. Today, systems with up to 8 parallel amplifiers exist that demonstrate a high combination efficiency at record performance values [1]. In order to substantially increase the number of amplifier channels even further to achieve the required performance, an additional integration step is necessary to decrease the complexity and cost of such systems. We present a new system design that contains a compact beam splitter/combiner, a piezo array for pathlength adjustments, a fiber with multiple signal cores and a phase detection scheme based on photodiode arrays and phase-alternating modulations.