Coherent Beam Combining of 37 Femtosecond Fiber Amplifiers

For the last few years, coherent beam combining (CBC) has been drastically increasing the performances of ytterbium-doped femtosecond fiber amplifiers, up to more than 10 mJ output energy and to the multi-kilowatt level [1,2]. CBC consists in coherently adding the output beams of several independent amplifiers seeded by a common source. This method involves both an efficient combination process along with a phase detection and control technique applied on all the beams to combine. However, for femtosecond pulses to reach the Joule level and address applications such as particles acceleration, several thousands of fibers need to be combined. Thus, highly scalable CBC architectures along with adapted phase measurements techniques need to be investigated.