title: Efficient, high-brightness wavelength-beam-combined commercial off-the-shelf diode stacks achieved by use of a wavelength-chirped volume Bragg grating.
abstract: We report a method of scaling the spatial brightness from commercial off-the-shelf diode laser stacks through wavelength beam combining, by use of a linearly wavelength-chirped volume Bragg grating (VBG). Using a three-bar commercial stack of broad-area lasers and a VBG, we demonstrate 89.5 W cw of beam-combined output with a beam-combining efficiency of 75%. The output beam has a propagation factor M2 approximately 26 on the slow axis and M2 approximately 21 on the fast axis. This corresponds to a brightness of approximately 20 MW/cm2 sr. To our knowledge, this is the highest brightness broad-area diode laser system. We achieve 81% coupling efficiency into a 100 microm, 0.22 N.A. fiber.
authors.affiliation: MIT Lincoln Laboratory, Lexington, Massachusetts 02420, USA. bchann@LL.mit.edu
authors.forename: B
authors.initials: B
authors.lastname: Chann
authors.forename: A K
authors.initials: AK
authors.lastname: Goyal
authors.forename: T Y
authors.initials: TY
authors.lastname: Fan
authors.forename: A
authors.initials: A
authors.lastname: Sanchez-Rubio
authors.forename: B L
authors.initials: BL
authors.lastname: Volodin
authors.forename: V S
authors.initials: VS
authors.lastname: Ban