Book contents
- Laser and Fiber Optic Gas Absorption Spectroscopy
- Laser and Fiber Optic Gas Absorption Spectroscopy
- Copyright page
- Dedication
- Contents
- Preface
- 1 Absorption Spectroscopy of Gases
- 2 DFB Lasers for Near-IR Spectroscopy
- 3 Wavelength Modulation Spectroscopy with DFB Lasers
- 4 Photoacoustic Spectroscopy with DFB Sources
- 5 Design and Application of DFB Laser Systems and Optical Fibre Networks for Near-IR Gas Spectroscopy
- 6 Principles of Fibre Amplifiers and Lasers for Near-IR Spectroscopy
- 7 Applications of Fibre Amplifiers and Lasers in Spectroscopy
- 8 Mid-IR Systems and the Future of Gas Absorption Spectroscopy
- Index
- References
3 - Wavelength Modulation Spectroscopy with DFB Lasers
Published online by Cambridge University Press: 07 April 2021
Book contents
- Laser and Fiber Optic Gas Absorption Spectroscopy
- Laser and Fiber Optic Gas Absorption Spectroscopy
- Copyright page
- Dedication
- Contents
- Preface
- 1 Absorption Spectroscopy of Gases
- 2 DFB Lasers for Near-IR Spectroscopy
- 3 Wavelength Modulation Spectroscopy with DFB Lasers
- 4 Photoacoustic Spectroscopy with DFB Sources
- 5 Design and Application of DFB Laser Systems and Optical Fibre Networks for Near-IR Gas Spectroscopy
- 6 Principles of Fibre Amplifiers and Lasers for Near-IR Spectroscopy
- 7 Applications of Fibre Amplifiers and Lasers in Spectroscopy
- 8 Mid-IR Systems and the Future of Gas Absorption Spectroscopy
- Index
- References
Summary
Based on Fourier analysis, a theoretical description is given of the harmonics arising from current modulation of a DFB laser with its wavelength scanned through a gas absorption line. It is shown that each harmonic consists of a primary component from the wavelength modulation and two secondary components arising from the mixing of the intensity and wavelength modulations, with additional components if the laser light-current characteristic is non-linear. The importance of the lock-in detection phase is discussed and the need for calibration-free, consistent operation in the face of possible drift of laser parameters with time or with aging. Two methods are examined for extraction of gas parameters, one based on the effect of gas absorption on the laser intensity modulation, with correction factors applied at high modulation indices, and the other based on measurement of the second harmonic signal normalised through the first harmonic. It is shown that both methods can give similar sensitivities, but the harmonic ratio method is much superior in noise performance at the expense of increased complexity in signal processing and uncertainty if the laser parameters are prone to drift.
Keywords
- Type
- Chapter
- Information
- Laser and Fiber Optic Gas Absorption Spectroscopy , pp. 53 - 84Publisher: Cambridge University PressPrint publication year: 2021
References
Silver, J. A., Frequency-modulation spectroscopy for trace species detection: theory and comparison among experimental methods, Appl. Opt., 31, (6), 707–717, 1992.CrossRefGoogle ScholarPubMed
Supplee, J. M., Whittaker, E. A. and Lenth, W., Theoretical description of frequency modulation and wavelength modulation spectroscopy, Appl. Opt., 33, (27), 6294–6302, 1994.CrossRefGoogle ScholarPubMed
Avetisov, V. G. and Kauranen, P., High-resolution absorption measurements by use of two-tone frequency-modulation spectroscopy with diode lasers, Appl. Opt., 36, (18), 4043–4054, 1997.CrossRefGoogle ScholarPubMed
Goldenstein, C. S., Spearrin, R. M., Jeffries, J. B. and Hanson, R. K., Infrared laser-absorption sensing for combustion gases, Prog. Energy Combust. Sci., 60, 132–176, 2016.Google Scholar
Kluczynski, P. and Axner, O., Theoretical description based on Fourier analysis of wavelength-modulation spectrometry in terms of analytical and background signals, Appl. Opt., 38, (27), 5803–5815, 1999.Google Scholar
Kluczynski, P., Lindberg, A. M. and Axner, O., Characterization of background signals in wavelength modulation spectrometry in terms of a Fourier based formalism, Appl. Opt., 40, (6), 770–782, 2001.Google Scholar
Schilt, S., Thevenaz, L. and Robert, P., Wavelength modulation spectroscopy: combined frequency and intensity laser modulation, Appl. Opt., 42, (33), 6728–6738, 2003.CrossRefGoogle ScholarPubMed
Stewart, G., Johnstone, W., Bain, J. R. P., Ruxton, K. and Duffin, K., Recovery of absolute gas absorption line shapes using tuneable diode laser spectroscopy with wavelength modulation – part 1: theoretical analysis, IEEE J. Lightwave Technol., 29, (6), 811–821, 2011.Google Scholar
Bain, J. R. P., Johnstone, W. , Ruxton, K., et al., Recovery of absolute gas absorption line shapes using tunable diode laser spectroscopy with wavelength modulation – part 2: experimental investigation, IEEE J. Lightwave Technol., 29, (7), 987–996, 2011.Google Scholar
Duffin, K., McGettrick, A. J., Johnstone, W., Stewart, G. and Moodie, D. G., Tunable diode laser spectroscopy with wavelength modulation: a calibration-free approach to the recovery of absolute gas absorption line-shapes, IEEE J. Lightwave Technol., 25, (10), 3114–3131, 2007.Google Scholar
McGettrick, A. J., Duffin, K., Johnstone, W., Stewart, G. and Moodie, D. G., Tunable diode laser spectroscopy with wavelength modulation: a phasor decomposition method for calibration free measurements of gas concentration and pressure, IEEE J. Lightwave Technol., 26, (4), 432–440, 2008.Google Scholar
Johnstone, W., McGettrick, A. J., Duffin, K., Cheung, A. and Stewart, G., Tunable diode laser spectroscopy for industrial process applications: system characterisation in conventional and new approaches, IEEE Sens. J., 8, (7), 1079–1088, 2008.Google Scholar
Ruxton, K., Chakraborty, A. L., Johnstone, W., et al., Tunable diode laser spectroscopy with wavelength modulation: elimination of residual amplitude modulation in a phasor decomposition approach, Sens. Actuators, B: Chem., 150, (1), 367–375, 2010.Google Scholar
Upadhyay, A. and Chakraborty, A. L., Residual amplitude modulation method implemented at the phase quadrature frequency of a 1650nm laser diode for line shape recovery of methane, IEEE Sens. J., 15, (2), 1153–1160, 2015.Google Scholar
Benoy, T., Lengden, M., Stewart, G. and Johnstone, W., Recovery of absorption line-shapes with correction for the wavelength modulation characteristics of DFB lasers, IEEE Photon., 8, (3), 2016.Google Scholar
Chakraborty, A. L., Ruxton, K., Johnstone, W., Lengden, M. and Duffin, K., Elimination of residual amplitude modulation in tuneable diode laser wavelength modulation spectroscopy using an optical fiber delay line, Opt. Express, 17, (12), 9602–9607, 2009.Google Scholar
Chakraborty, A. L., Ruxton, K. and Johnstone, W., Influence of the wavelength-dependence of fiber couplers on the background signal in wavelength modulation spectroscopy with RAM nulling, Opt. Express, 18, (1), 267–280, 2010.Google Scholar
Chakraborty, A. L., Ruxton, K., Johnstone, W., Suppression of intensity modulation contributions to signals in second harmonic wavelength modulation spectroscopy, Opt. Lett., 35, (14), 2400–2402, 2010.CrossRefGoogle ScholarPubMed
Hobbs, P. C., Ultra-sensitive laser measurements without tears, Appl. Opt., 36, (4), 903–920, 1997.Google Scholar
Bain, J. R. P., Lengden, M., Stewart, G. and Johnstone, W., Recovery of absolute absorption line shapes in tunable diode laser spectroscopy using external amplitude modulation with balanced detection, IEEE Sens. J., 16, (3), 675–680, 2016.Google Scholar
Li, H., Rieker, G. B., Liu, X., Jeffries, J. B. and Hanson, R. K., Extension of wavelength modulation spectroscopy to large modulation depth for diode laser absorption measurements in high-pressure gases, Appl. Opt., 45, (5), 1052–1061, 2006.Google Scholar
Rieker, G. B., Jeffries, J. B. and Hanson, R. K., Calibration-free wavelength-modulation spectroscopy for measurements of gas temperature and concentration in harsh environments, Appl. Opt., 48, (29), 5546–5560, 2009.CrossRefGoogle ScholarPubMed
Sun, K., Chao, X., Sur, R., et al., Analysis of calibration-free wavelength-scanned wavelength modulation spectroscopy for practical gas sensing using tunable diode lasers, Meas. Sci. Technol., 24, (12), 125203–125214, 2013.Google Scholar
Goldenstein, C. S., Strand, C. L., Schultz, I. A., et al., Fitting of calibration-free scanned-wavelength-modulation spectroscopy spectra for determination of gas properties and absorption lineshapes, Appl. Opt., 53, (3), 356–367, 2014.Google Scholar
Goldenstein, C. S., Thesis: Wavelength-modulation spectroscopy for determination of gas properties in hostile environments, 2014. [Online]. Available: https://purl.stanford.edu/fg346yx4996 (accessed April 2020)Google Scholar
Benoy, T., Wilson, D., Lengden, M., et al., Measurement of CO2 concentration and temperature in an aero-engine exhaust plume using wavelength modulation spectroscopy, IEEE Sens. J., 17, (19), 6409–6417, 2017.Google Scholar
Upadhyay, A. and Chakraborty, A. L., Calibration-free 2f WMS with in situ real-time laser characterization and 2f RAM nulling, Opt. Lett., 40, (17), 4086–4089, 2015.Google Scholar
Upadhyay, A., Wilson, D., Lengden, M., et al., Calibration-free WMS using a cw-DFB-QCL, a VCSEL, and an edge-emitting DFB laser with in-situ real-time laser parameter characterization, IEEE Photon., 9, (2), 6801217, 2017.Google Scholar
Upadhyay, A., Lengden, M., Wilson, D., et al., A new RAM normalized 1f -WMS technique for the measurement of gas parameters in harsh environments and a comparison with 2f⁄1f, IEE Photon., 10, (6), 6804611, 2018.Google Scholar