Method to synthesize polynomial current waveforms and intensity compensation functions for DFB lasers in digital sweep integration gas analyzers

Abstract

With analysis methods using digital sweep integration of the absorbance function, linear current ramps can produce non-linear laser intensity and wavenumber functions from distributed feedback lasers. These non-linear functions produce offset and gain errors in mole fraction estimates on tunable diode laser gas analyzers. A method is described to synthesize polynomial current waveforms and laser intensity compensation functions to give linear wavenumber functions and to minimize the offset error. Quantitative and qualitative results are presented to evaluate reduction in mole fraction errors. © 2002 Elsevier Science B.V. All rights reserved.