Coherent beam combining enables power scaling beyond the limits of single amplifiers. Therefore, improving the performance and simplicity of coherent combination techniques is of great interest for many high power applications. Here, we show all-fiber coherent beam combining of two ytterbium doped amplifiers with and without a dedicated phase actuator and a total output power up to 25 W. Instead of a dedicated phase actuator, we directly controlled the two ytterbium amplifiers to also stabilize their relative phase. We compared the performance of this method with phase stabilization using two piezo driven fiber stretchers. In both cases, power noise was dominated by the single amplifier.
© 2012 Optical Society of America
Original Manuscript: January 4, 2012
Revised Manuscript: February 14, 2012
Manuscript Accepted: February 20, 2012
Published: March 26, 2012
Henrik Tünnermann, Yan Feng, Jörg Neumann, Dietmar Kracht, and Peter Weßels, "All-fiber coherent beam combining with phase stabilization via differential pump power control," Opt. Lett. 37, 1202-1204 (2012)