Simulation-based comparison of noise effects in wavelength modulation spectroscopy and direct absorption TDLAS
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A simulative investigation of noise effects in wavelength modulation spectroscopy (WMS) and direct absorption diode laser absorption spectroscopy is presented. Special attention is paid to the impact of quantization noise of the analog-to-digital conversion (ADC) of the photodetector signal in the two detection schemes with the goal of estimating the necessary ADC resolution for each technique. With laser relative intensity noise (RIN), photodetector shot noise and thermal amplifier noise included, the strategies used for noise reduction in direct and wavelength modulation spectroscopy are compared by simulating two respective systems. Results show that because of the combined effects of dithering by RIN and signal averaging, the resolutions required for the direct absorption setup are only slightly higher than for the WMS setup. Only for small contributions of RIN an increase in resolution will significantly improve signal quality in the direct scheme.
KeywordsShot Noise Quantization Noise Direct Absorption Scanning Frequency Relative Intensity Noise
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- 10.L. Schuchman, IEEE Trans. Instrum. Meas. 12, 162 (1964) Google Scholar
- 16.U. Platt, J. Stutz, Differential Optical Absorption Spectroscopy: Principles and Applications (Springer, Berlin, 2007) Google Scholar
- 18.M. Johnson, Photodetection and Measurement (McGraw-Hill, New York, 2003) Google Scholar
- 20.D. Derickson, Fiber Optic Test and Measurement (Prentice Hall, Upper Saddle River, 1998) Google Scholar
- 21.K. Petermann, Laser Diode Modulation and Noise (Kluwer Academic, Dordrecht, 1991) Google Scholar
- 22.E. Milotti, arXiv:physics/0204033 (2002)
- 25.G.B. Clayton, S. Winder, G. Clayton, Operational Amplifiers (Newnes, Oxford, 2003) Google Scholar
- 26.S. Franco, Design with Operational Amplifiers and Analog Integrated Circuits (McGraw-Hill, New York, 2002) Google Scholar