Highly scalable coherent fiber combining
Thales Research & Technology, 1 avenue Augustin Fresnel, 91767 Palaiseau, France
a e-mail: firstname.lastname@example.org
Received: 18 December 2014
Revised: 31 August 2015
Published online: 26 October 2015
An architecture for active coherent fiber laser beam combining using an interferometric measurement is demonstrated. This technique allows measuring the exact phase errors of each fiber beam in a single shot. Therefore, this method is a promising candidate toward very large number of combined fibers. Our experimental system, composed of 16 independent fiber channels, is used to evaluate the achieved phase locking stability in terms of phase shift error and bandwidth. We show that only 8 pixels per fiber on the camera is required for a stable close loop operation with a residual phase error of λ/20 rms, which demonstrates the scalability of this concept. Furthermore we propose a beam shaping technique to increase the combining efficiency.
© EDP Sciences, Springer-Verlag, 2015