Abstract

Coherent phase combining of fiber lasers provide an attractive means of reaching high output laser power by scaling up the available energy while keeping fibers intrinsic advantages of compactness, reliability, efficiency, and beam quality. Active phase locking schemes involve phase detection, which is currently implemented using LOCSET technique [1], heterodyne techniques [2], or by analyzing the interference pattern of the output fibers recorded on a camera [3]. The last method performs a collective measurement of the phase distribution with a single sensor, and is therefore directly scalable to a large number of fibers. However, reported demonstrations using this technique were limited to few tens of Hz of loop bandwidth [4]. In this Communication, we present an original system which coherently combines 16 independent fibers using interferometric technique for phase control, and operates at a 1 kHz feedback loop frequency. To our best knowledge, this is the first demonstration of an interferometric combining setup at the kHz regime.

© 2013 IEEE