We introduce orthogonally coded modulations for active coherent beam combining (CBC), and show how using Walsh codes enables the increase of the number of combined channels. Analytical, numerical, and experimental results are presented and compared to the standard multifrequency dithering technique, demonstrating that at least 5 times more fibers can be combined using the same modulation frequency. The modulation format excluded, no particular changes in the system need to be introduced and the benefits of active coherent beam combing, such as atmospheric turbulence compensation capability, are kept unchanged. Finally, we point out that this approach can be applied in partially CBC.
© 2014 Optical Society of America
Lasers and Laser Optics
Original Manuscript: July 8, 2013
Revised Manuscript: January 23, 2014
Manuscript Accepted: January 27, 2014
Published: March 3, 2014
A. Azarian, P. Bourdon, L. Lombard, Y. Jaouën, and O. Vasseur, "Orthogonal coding methods for increasing the number of multiplexed channels in coherent beam combining," Appl. Opt. 53, 1493-1502 (2014)