High-sensitivity, large dynamic range, auto-calibration methane optical sensor using a short confocal Fabry–Perot cavity

Dong, Lei; Yin, Wangbao; Ma, Weiguang; Zhang, Lei; Jia, Suotang

doi:10.1016/j.snb.2007.04.030

Cited by 25 publications

(13 citation statements)

References 33 publications

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“…In the WM-ATLAS case, the laser wavelength is also driven with a typical saw-tooth or triangular waveform, but this is also modulated with another faster signal waveform [ 4 , 5 ]. Usually, sensors based on the WM-ATLAS technique have a minimum detectable absorbance in the order of 10

; this is quite superior to that typically achieved by sensors based on DA-ATLAS, which is in the order of 10

[ 10 ]. For instance, the sensor based on WM-ATLAS designed by [ 6 ] was able to simultaneously detect CH

and H

S with a minimum detection limit of 1.1 ppm m and 15 ppm m, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…An example of a typical sensor based on DA-ATLAS is the one presented by [ 7 ], which can detect a minimum concentration of 0.2% of CH

. One disadvantage of WM-ATLAS sensors is that their highest detectable concentration typically lies within a narrow concentration range (<1%), while sensors based on DA-ATLAS usually have a larger dynamic range [ 10 ]. Furthermore, as in the ATLAS sensors, the laser line emission is tuned, therefore these will generate an output signal in the time domain.…”

Section: Introductionmentioning

confidence: 99%

“…For example, a relationship can be established between the concentration and one statistics feature of the signal generated by the sensor. Some commonly-used statistics features are the peak amplitude [ 14 ], the area under the curve [ 10 ] and the Root-Mean Square (RMS) [ 7 ]. These kinds of relationships are easy to compute, and therefore, the gas concentration can be determined straightforwardly.…”

Section: Introductionmentioning

confidence: 99%

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Tailored Algorithm for Sensitivity Enhancement of Gas Concentration Sensors Based on Tunable Laser Absorption Spectroscopy

Rodríguez

Guzmán-Chávez

Baeza-Serrato

2018

Sensors

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In this work, a novel tailored algorithm to enhance the overall sensitivity of gas concentration sensors based on the Direct Absorption Tunable Laser Absorption Spectroscopy (DA-ATLAS) method is presented. By using this algorithm, the sensor sensitivity can be custom-designed to be quasi constant over a much larger dynamic range compared with that obtained by typical methods based on a single statistics feature of the sensor signal output (peak amplitude, area under the curve, mean or RMS). Additionally, it is shown that with our algorithm, an optimal function can be tailored to get a quasi linear relationship between the concentration and some specific statistics features over a wider dynamic range. In order to test the viability of our algorithm, a basic C2H2 sensor based on DA-ATLAS was implemented, and its experimental measurements support the simulated results provided by our algorithm.

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; this is quite superior to that typically achieved by sensors based on DA-ATLAS, which is in the order of 10

[ 10 ]. For instance, the sensor based on WM-ATLAS designed by [ 6 ] was able to simultaneously detect CH

and H

S with a minimum detection limit of 1.1 ppm m and 15 ppm m, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…An example of a typical sensor based on DA-ATLAS is the one presented by [ 7 ], which can detect a minimum concentration of 0.2% of CH

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Tailored Algorithm for Sensitivity Enhancement of Gas Concentration Sensors Based on Tunable Laser Absorption Spectroscopy

Rodríguez

Guzmán-Chávez

Baeza-Serrato

2018

Sensors

View full text Add to dashboard Cite

show abstract

“…In Ref. [11], a methane sensor based on a short confocal Fabry-Perot cavity was realized. Although the sensor possesses high sensitivity and wide dynamic range, the Fabry-Perot cavity only increases the reaction length between the light and gas.…”

Section: Introductionmentioning

confidence: 99%

A Method for the Measurement of Methane Gas Based on Multi-beam Interferometry

Ye¹,

Li²

2013

Journal of the Optical Society of Korea

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A method for the measurement of the concentration of methane is experimentally demonstrated. The wavelength filter and gas cell are combined by using one Fabry-Perot etalon, which is filmed with the reflectivity of 96%. The optical broadband source is not only filtered to match the absorption wavelength of methane, but also absorbed by the methane in the same Fabry-Perot etalon. The concentration of the methane can be detected directly by measuring the transmission intensity. Compared with the conventional method, the proposed method possesses low costand high stability.

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“…Engeln et al, 1996;Romanini et al, 1997) and noise-immune cavity-enhanced optical-heterodyne molecular spectroscopy (NICE-OHMS) (Ye et al, 1998) are among two of the most promising resonant system configurations. Even though high sensitivities have been demonstrated with these systems (Paldus and Kachanov, 2005;He et al, 2014;Giel Berden et al, 2000;Dong et al, 2007;Orr and He, 2011;He et al, 2010), resonant cells are not suitable to this particular application due to their sensitivity to vibration, high resonant cavity cost, and the complexities associated with coupling light out of the cavity with optical fibers (Huang and Lehmann, 2010;He et al, 2014).…”

Section: Advancements In Tdlasmentioning

confidence: 99%

Design of an Optical Fiber-Coupled Sensor for Ambient Methane Measurement

Schoonbaert¹

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A tunable diode laser system was developed for remote monitoring of ambient methane using fiber optically connected all-optical sensor heads. Experiments were performed to quantitatively evaluate the influence of selected system hardware and software configurations, with the further goal of enabling measurements of ambient methane concentrations over an intrinsically-safe fiber optic network at sufficient precision and sensitivity to detect unknown fugitive emission sources. The designed system could switch between the sweep integration (SI) and wavelength modulation spectroscopy (WMS) detection methods, which inferred the methane volume mixing ratio from an absorption or second-harmonic (2f) feature respectively. Signals controlling the laser injection current were optimized to balance trade-offs between measurement precision and system sensitivity, and fiber optic components were thermally stabilized to reduce system drift. Starting from this base system, experiments were performed to evaluate the effectiveness of theory-based and experimental calibration methods, software and dual laser approaches to estimating the absorption-free intensity, different signal processing approaches to suppress effects of residual amplitude modulation (RAM) of the laser output intensity, and methods to reduce system drift. Tests also considered effects of varying fiber lengths between the central laser control hardware and the remotely located optical sensor heads. Finally, long-term stability was evaluated by quantifying bias (drift) and precision uncertainty in tests up to 16 months after initial calibration. The best measurement performance was achieved using the WMS method with thermally stabilized optical components within the central control hardware combined with a theory-based calibration, automated daily calibration supported by concurrent softwarebased estimation of the absorption-free intensity, and pair-wise averaging of the 2f feature maxima in each sweep period to suppress effects of RAM. At an averaging time of 1 s and methane concentrations between 1.0 and 50 ppm v , the system implementing the 2f-WMS method surpassed the methane volume mixing ratio measurement targets with a precision of 1.6 ppm v (absorbance of 6.57×10 -7 cm -1 ) and lower detection limit (LDL) of 1.5 ppm v (6.13×10 -7 cm -1 ). In achieving these values, thermal stabilization was responsible for a 93% reduction in the precision uncertainty; adding the concurrent software-based absorption-free intensity estimate netted a further reduction of 73%; and implementing RAM suppression via pair-wise averaging of the resolved 2f features within each sweep period technique allowed a further reduction of 9%.3

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High-sensitivity, large dynamic range, auto-calibration methane optical sensor using a short confocal Fabry–Perot cavity

Cited by 25 publications

References 33 publications

Tailored Algorithm for Sensitivity Enhancement of Gas Concentration Sensors Based on Tunable Laser Absorption Spectroscopy

Tailored Algorithm for Sensitivity Enhancement of Gas Concentration Sensors Based on Tunable Laser Absorption Spectroscopy

A Method for the Measurement of Methane Gas Based on Multi-beam Interferometry

Design of an Optical Fiber-Coupled Sensor for Ambient Methane Measurement

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