Tunable diode and fibre laser spectroscopy in the near-IR for measurement of gas parameters

George Stewart, Walter Johnstone, Norhana Arsad, Kevin Duffin

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Citations (Scopus)

Abstract

There has been much research performed in recent years on tunable diode laser spectroscopy for detection of gases such as methane, carbon dioxide, acetylene, etc., which possess near-IR absorption lines. To attain adequate sensitivity with weak near-IR lines, wavelength modulation spectroscopy with phase-sensitive detection is normally employed. However injection current modulation of diode lasers produces both wavelength and amplitude modulation, with a phase shift dependent on the modulation frequency. This results in residual amplitude modulation on the output and in distortion of the harmonic signals derived from the absorption line. These are important issues for calibration and where it is desired to accurately recover the line-shape function in order to make simultaneous measurements of gas concentration, pressure or temperature in industrial applications. Here we discuss how calibration-free measurements may be obtained with diode lasers and explore the implications for fibre laser based systems for spectroscopy which conventionally employ thermal or piezoelectric tuning of the wavelength. In particular, we consider modulation techniques which may be applied to ring fibre lasers which use un-pumped erbium fibre as a saturable absorber to prevent mode-hopping or to DFB fibre lasers which use a short cavity with a Bragg grating to ensure single mode operation.

Original languageEnglish
Title of host publicationProceedings of SPIE - The International Society for Optical Engineering
Volume7003
DOIs
Publication statusPublished - 2008
Externally publishedYes
EventOptical Sensors 2008 - Strasbourg
Duration: 7 Apr 200810 Apr 2008

Other

OtherOptical Sensors 2008
CityStrasbourg
Period7/4/0810/4/08

Fingerprint

Laser spectroscopy
Fiber lasers
laser spectroscopy
fiber lasers
Semiconductor lasers
Amplitude modulation
semiconductor lasers
Modulation
modulation
Wavelength
Gases
gases
Spectroscopy
Calibration
Saturable absorbers
Bragg gratings
Ring lasers
Distributed feedback lasers
Erbium
wavelengths

Keywords

  • DFB lasers
  • Diode laser spectroscopy
  • Fibre lasers
  • Fibre sensors
  • Gas sensors
  • Wavelength modulation spectroscopy

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

Cite this

Stewart, G., Johnstone, W., Arsad, N., & Duffin, K. (2008). Tunable diode and fibre laser spectroscopy in the near-IR for measurement of gas parameters. In Proceedings of SPIE - The International Society for Optical Engineering (Vol. 7003). [700319] https://doi.org/10.1117/12.779976

Tunable diode and fibre laser spectroscopy in the near-IR for measurement of gas parameters. / Stewart, George; Johnstone, Walter; Arsad, Norhana; Duffin, Kevin.

Proceedings of SPIE - The International Society for Optical Engineering. Vol. 7003 2008. 700319.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Stewart, G, Johnstone, W, Arsad, N & Duffin, K 2008, Tunable diode and fibre laser spectroscopy in the near-IR for measurement of gas parameters. in Proceedings of SPIE - The International Society for Optical Engineering. vol. 7003, 700319, Optical Sensors 2008, Strasbourg, 7/4/08. https://doi.org/10.1117/12.779976
Stewart G, Johnstone W, Arsad N, Duffin K. Tunable diode and fibre laser spectroscopy in the near-IR for measurement of gas parameters. In Proceedings of SPIE - The International Society for Optical Engineering. Vol. 7003. 2008. 700319 https://doi.org/10.1117/12.779976
Stewart, George ; Johnstone, Walter ; Arsad, Norhana ; Duffin, Kevin. / Tunable diode and fibre laser spectroscopy in the near-IR for measurement of gas parameters. Proceedings of SPIE - The International Society for Optical Engineering. Vol. 7003 2008.
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