Frequency stabilization of distributed-feedback laser diodes at 1572 nm for lidar measurements of atmospheric carbon dioxide

Kenji Numata; Jeffrey R Chen; Stewart T Wu; James B Abshire; Michael A Krainak

doi:10.1364/AO.50.001047

Frequency stabilization of distributed-feedback laser diodes at 1572 nm for lidar measurements of atmospheric carbon dioxide

Appl Opt. 2011 Mar 1;50(7):1047-56. doi: 10.1364/AO.50.001047.

Authors

Kenji Numata¹, Jeffrey R Chen, Stewart T Wu, James B Abshire, Michael A Krainak

Affiliation

¹ Department of Astronomy, University of Maryland, College Park, Maryland 20742, USA. kenji.numata@nasa.gov

PMID: 21364729
DOI: 10.1364/AO.50.001047

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.