Measurements of CO, CO_2, OH, and H_2O in room-temperature and combustion gases by use of a broadly current-tuned multisection InGaAsP diode laser

Abstract

A new laser technology that achieves nearly 100-nm quasi-continuous tuning with only injection-current control in a four-section grating-coupler sampled-reflector laser was used to detect CO and CO(2) simultaneously in room-temperature gas mixtures. The same grating-coupler sampled-reflector laser was used to perform in situ measurements of CO, H(2)O, and OH in the exhaust gases of a CH(4)-air flame. This laser is being evaluated for inclusion in a multispecies combustion-emissions exhaust-analysis sensor, and its operational characteristics as they have an impact on gas sensing are described. Preliminary results suggest that this single laser can be used to replace multilaser sensor configurations for some combustion-emissions monitoring applications.

Multi-species sensing using multi-mode absorption spectroscopy with mid-infrared interband cascade lasers

“…This system provided a 5-ns pulsed output at up to 150 kHz, but with a relatively broad single-mode linewidth of 1.3 cm −1 [3]. Specialised architectures based on multi-section diodes and integrated devices based on distributed feedback, DFB, lasers for telecoms applications, have been implemented to allow several wavelengths to be emitted simultaneously for selected multi-species detection [4,5]. External cavity diode lasers, ECDLs, can extend the MHF of some systems but involve very tight mechanical tolerances on the cavity.…”

“…Previously, MUMAS has been demonstrated for the measurement of concentration, temperature and pressure of molecular oxygen using multi-mode near-IR diode lasers [18], the detection of C 2 H 2 [20], CO and CO 2 [21] using an Er:Yb:glass microlaser, as well as the simultaneous detection of C 2 H 2 , CH 4 and N 2 O in the 1.5 μm region [22]. Extension to the important mid-IR range between 3 and 4 μm was demonstrated using a difference frequency generation, DFG, system based on the Er:Yb:glass microlaser for the simultaneous detection of CH 4 and NH 3 [23].…”

“…Extension to the important mid-IR range between 3 and 4 μm was demonstrated using a difference frequency generation, DFG, system based on the Er:Yb:glass microlaser for the simultaneous detection of CH 4 and NH 3 [23]. More recently, MUMAS using a new generation of interband cascade lasers, ICLs, at 3.6 μm was demonstrated for simultaneous detection of CH 4 , C 2 H 2 and H 2 CO in a mixture [24].…”

Demonstration of Vernier effect tuning in tunable twin-guide laser diodes

“…They can be used to introduce new functionalities, like packet switching and wavelength conversion, and thereby make optical networks more flexible. Besides these telecommunications applications, tunable laser diodes are also highly attractive light sources for gas sensing applications [2] as well as for fibre Bragg grating (FBG) based sensor devices [3].…”

Multi-mode absorption spectroscopy using a quantum cascade laser for simultaneous detection of NO and H2O

“…A variety of broadband spectroscopy methods have been developed that allow detection of multiple species over a wide spectral range but not all are available in the mid-IR. These include use of multi-section diodes, broadband or wavelength agile light sources and correlation spectroscopic methods [6][7][8][9][10][11][12]. The wide bandwidth "frequency combs" available from mode-locked lasers has been exploited for broadband spectroscopy but usually involve complex laser systems and high resolution dispersion optics [13,14].…”