title: Dispersion-compensated wavelength beam combining of quantum-cascade-laser arrays.
abstract: A multiwavelength array of distributed feedback (DFB) quantum cascade lasers (QCLs) that spans λ = 8.28 to 9.62 μm is wavelength beam combined (WBC) using both single-grating and dual-grating designs. WBC with a single grating results in a pointing error of 3-times the beam divergence for a single laser and arises from the nonlinear dispersion of the grating. By adding a second grating to compensate for the nonlinear dispersion, the pointing error is reduced to only 13% of the beam divergence for a single laser. A transceiver based on the dual-grating-WBC QCL was used to measure the transmittance of a polymer sheet placed between itself and a retroreflector over a round-trip distance of 70 meters.
authors.affiliation: MIT Lincoln Laboratory, Lexington, Massachusetts 02420, USA. agoyal@ll.mit.edu
authors.forename: Anish K
authors.initials: AK
authors.lastname: Goyal
authors.forename: Melissa
authors.initials: M
authors.lastname: Spencer
authors.forename: Oleg
authors.initials: O
authors.lastname: Shatrovoy
authors.forename: Benjamin G
authors.initials: BG
authors.lastname: Lee
authors.forename: Laurent
authors.initials: L
authors.lastname: Diehl
authors.forename: Christian
authors.initials: C
authors.lastname: Pfluegl
authors.forename: Antonio
authors.initials: A
authors.lastname: Sanchez
authors.forename: Federico
authors.initials: F
authors.lastname: Capasso
mesh_terms: D016477:Artifacts; D003198:Computer Simulation; D017076:Computer-Aided Design; D004867:Equipment Design; D019544:Equipment Failure Analysis; D007834:Lasers; D008027:Light; D008962:Models, Theoretical; D010783:Photometry / Q000295:instrumentation*; D012031:Refractometry / Q000295:instrumentation*; D012542:Scattering, Radiation