We present what is to our knowledge the first near-infrared diode-laser-based absorption spectrometer that is suitable for simultaneous <i>in situ</i> measurement of carbon monoxide, water vapor, and temperature in the combustion chamber (20-m diameter, 13-m path length) of a 600-MW lignite-fired power plant. A fiber-coupled distributed-feedback diode-laser module at 1.56 μm served for CO detection, and a Fabry-Perot diode laser at 813 nm was used to determine H<sub>2</sub>O concentrations and temperature from multiline water spectra. Despite severe light losses (transmission, <10<sup>−3</sup>) and strong background radiation we achieved a resolution of 1.9 × 10<sup>−4</sup> (1ς) fractional absorption, equivalent to 200 parts in 10<sup>6</sup> by volume of CO (at 1450 K, 10<sup>5</sup> Pa) with 30-s averaging time.
© 2003 Optical Society of America
(120.0120) Instrumentation, measurement, and metrology : Instrumentation, measurement, and metrology
(120.1740) Instrumentation, measurement, and metrology : Combustion diagnostics
(140.0140) Lasers and laser optics : Lasers and laser optics
(140.2020) Lasers and laser optics : Diode lasers
Holger Teichert, Thomas Fernholz, and Volker Ebert, "Simultaneous In Situ Measurement of CO, H2O, and Gas Temperatures in a Full-Sized Coal-Fired Power Plant by Near-Infrared Diode Lasers," Appl. Opt. 42, 2043-2051 (2003)