title: Diffractive-optics-based beam combination of a phase-locked fiber laser array.
abstract: A diffractive optical element (DOE) is used as a beam combiner for an actively phase-locked array of fiber lasers. Use of a DOE eliminates the far-field sidelobes and the accompanying loss of beam quality typically observed in tiled coherent laser arrays. Using this technique, we demonstrated coherent combination of five fiber lasers with 91% efficiency and M2=1.04. Combination efficiency and phase locking is robust even with large amplitude and phase fluctuations on the input laser array elements. Calculations and power handling measurements suggest that this approach can scale to both high channel counts and high powers.
authors.affiliation: Northrop Grumman Space Technology, One Space Park, R1-1196, Redondo Beach, California 90278, USA.
authors.forename: Eric C
authors.initials: EC
authors.lastname: Cheung
authors.forename: James G
authors.initials: JG
authors.lastname: Ho
authors.forename: Gregory D
authors.initials: GD
authors.lastname: Goodno
authors.forename: Robert R
authors.initials: RR
authors.lastname: Rice
authors.forename: Josh
authors.initials: J
authors.lastname: Rothenberg
authors.forename: Peter
authors.initials: P
authors.lastname: Thielen
authors.forename: Mark
authors.initials: M
authors.lastname: Weber
authors.forename: Michael
authors.initials: M
authors.lastname: Wickham