We report standoff open path atmospheric CO2 monitoring with a field deployable, turn key system including a continuous wave (CW) distributed feedback (DFB) laser and an erbium. doped fiber amplifier (EDFA) at 1.5-mum. A sensitivity of 28-ppm was achieved over 1.5-km of open air with 200-pW of received power, a 10s acquisition time. and a peak absorption cross section of 8x10(-23). This sensitivity corresponds to an error in fractional absorbance of 8x10(-3). Closed cell lab sensitivities are better than 3000ppm*m, an error in fractional absorbance of 5x10(-4). These results have been achieved using space qualified laser components, un-cooled InGaAs detectors, and off the shelf electronics in a rugged all fiber architecture.
A number of gases present in the atmosphere play roles of interest to various parties. These are CO2 for its impact on understanding of global sources and sinks of Carbon, CH4 and H2O and their importance for global climate change, HCl and its importance in chemical processes. A space-borne sensor using multiple-wavelength Laser Absorption Spectroscopy (LAS) and mature CW fiber telecom lasers can address the critical questions concerning present and future patterns in these gases. The sensor identified above was designed from the outset using Taguchi Robust design techniques because of the need to adjust to varying science measurement requirements and technology capability as well as achieving optimum performance for optimum cost. The results describe a sensor with a SNR of 150 with a power aperture product of 3.92 watts-m(2) on the absorption line is sufficient to meet the science requirements of 0.5% accuracy for determining the column density of CO2.
Get PDF Email Share Share with Facebook Tweet This Post on reddit Share with LinkedIn Add to CiteULike Add to Mendeley Add to BibSonomy Get Citation Copy Citation Text W. Sharp, M. Dobbs, J. Zimmerman, and M. C. Abrams, "Optimization of a differential absorption LIDAR using parameter design," in Optical Remote Sensing, A. Sawchuk, ed., Vol. 52 of OSA Trends in Optics and Photonics (Optica Publishing Group, 2001), paper OThA1. Export Citation BibTex Endnote (RIS) HTML Plain Text Citation alert Save article
