PISTIL interferometry diagnosis on a 61 channels coherent beam combining digital laser

Coherent beam combining (CBC) opens the way to a new paradigm in laser architecture [1] . The quest to high peak and average power indeed faces several fundamental limitations (transverse amplified spontaneous emission in wide amplifiers, thermal management issues) which can be addressed when relying on numerous smaller scale reliable lasers coherently combined. Achieving CBC for a large number of amplifiers will not only rely on the use of an efficient phase-locking scheme but also on fiber management inside the laser head (such as accurate angular and lateral positioning, at µm or mrad levels), optics, and amplifiers management as well as laboratory environment control. An accurate diagnosis of the laser array is mandatory in order to get significant feedback on its design, and potentially improve or stabilize its behavior, either in phase-locked loop or in free run.