title: Frequency stabilization of distributed-feedback laser diodes at 1572 nm for lidar measurements of atmospheric carbon dioxide.
abstract: We demonstrate a wavelength-locked laser source that rapidly steps through six wavelengths distributed across a 1572.335 nm carbon dioxide (CO(2)) absorption line to allow precise measurements of atmospheric CO(2) absorption. A distributed-feedback laser diode (DFB-LD) was frequency-locked to the CO(2) line center by using a frequency modulation technique, limiting its peak-to-peak frequency drift to 0.3 MHz at 0.8 s averaging time over 72 hours. Four online DFB-LDs were then offset locked to this laser using phase-locked loops, retaining virtually the same absolute frequency stability. These online and two offline DFB-LDs were subsequently amplitude switched and combined. This produced a precise wavelength-stepped laser pulse train, to be amplified for CO(2) measurements.
authors.affiliation: Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA. kenji.numata@nasa.gov
authors.forename: Kenji
authors.initials: K
authors.lastname: Numata
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Chen
authors.forename: Stewart T
authors.initials: ST
authors.lastname: Wu
authors.forename: James B
authors.initials: JB
authors.lastname: Abshire
authors.forename: Michael A
authors.initials: MA
authors.lastname: Krainak