Measurement technique for methane concentration by wavelength scanning of a distributed-feedback laser

Wang, H.; Wang, Q.; Chang, Jun; Zhang, X.; Zhang, S.; Ni, Jiasheng

doi:10.1134/s11490-008-4025-z

Cited by 17 publications

(11 citation statements)

References 6 publications

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“…As conventionally practiced for the near-and mid-IR diode laser sensors, subtraction or division is the most widely used method during normalization processing [12][13][14]. In contrast, the designed optical fiber H 2 O sensing system in our research adopts a shot-noise-level-performance noise canceller, called the balanced ratiometric detector (BRD) technique.…”

Section: A Water Vapor Measurement Inside Optical Componentsmentioning

confidence: 99%

Measurement and analysis of water vapor inside optical components for optical fiber H₂O sensing system

Wang

Chang

Song³

et al. 2013

Appl. Opt.

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Water vapor existing inside internal end-face gaps of optical components of an optical fiber H2O sensing system makes it possible to influence the measurement accuracy and stability. The influence principle has been briefly analyzed based on the structure of three main optical components: a distributed feedback laser diode (DFB-LD), a collimator, and a photoelectric diode (PD). With application of a differential technique, the influence of water vapor inside the DFB-LD can be removed. With reasonable recombination of the collimator and the PD in a dual-beam detection system, the influence of water vapor inside the collimator and the PD's end-face gaps has been suppressed from more than 1.57×10(-3) to as low as -2.175×10(-5) in absorbance. After H2O isolation processing water vapor inside the end-face gaps of the DFB-LD, the collimator, and the PD can be utilized as a reference to design a simple but feasible H2O sensor. As a result, good linearity with an R2 of 0.9964 has been realized in a concentration range of 39-2110 ppm during an application test, and a long-term test of the designed H2O sensor against the S8000 with a difference of 10 ppm has been achieved.

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Section: A Water Vapor Measurement Inside Optical Componentsmentioning

confidence: 99%

Measurement and analysis of water vapor inside optical components for optical fiber H₂O sensing system

Wang

Chang

Song³

et al. 2013

Appl. Opt.

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“…where P v is the partial pressure of water vapor, and P ws is the saturation water vapor pressure. In this optical absorption humidity sensor, the presence of water vapor is determined according to the Beer-Lambert law by which the amount of water vapor is related to the power output [8] as…”

Section: Principlementioning

confidence: 99%

Optical humidity sensor based on air guided photonic crystal fiber

et al. 2012

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We proposed a novel relative humidity (RH) sensor based on the air guided photonic crystal fiber (AGPCF) using the direct absorption spectroscopic method in this paper. The wavelength scanning around the water vapor absorption peak around 1368.59 nm was realized by injecting the saw-tooth modulated current to a distributed-feedback laser diode. A reference signal was used as a zero absorption baseline and to help reduce the interference from the distributed-feedback laser source and probed region. The humidity level was determined by the normalized voltage difference between the reference signal and sensor signal at the peak of water vapor absorption. We demonstrated that a length of 5-cm AGPCF with a fixed small air gap between the single mode fiber (SMF) and hollow core fiber as an opening achieved a humidity detection resolution of around 0.2% RH over the range 0 to 90% RH which did not require the use of any hygroscopic coating material.

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“…On-line methane gas monitoring is generally desired in these projects. Several techniques have been developed to monitor the concentration of methane gas [1][2][3][4][5][6][7]. During the last decade there has been a great deal of interest in the development of optical gas sensors using the near-IR absorption lines of gas [8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Multi-Channel Optical Fiber Methane Monitoring System Based on Laser Absorption Spectroscopy

Zhao

Wei

et al. 2012

2012 Asia-Pacific Power and Energy Engineering Conference

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A multi-channel optical fiber methane monitoring system is researched for detecting the concentration of methane gas. In this system, distributed feedback laser is employed as light source. The narrow absorption line of the laser could effectively eliminates the cross sensitivity to moisture, ethane or other gases. Since the sensor head is made without any active electrical components, it is intrinsically safe when used in the hazard environment such as coal mines. The results show that the monitoring system has a great application in the comprehensive utilization of coalmine methane and ventilation air methane.

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Measurement technique for methane concentration by wavelength scanning of a distributed-feedback laser

Cited by 17 publications

References 6 publications

Measurement and analysis of water vapor inside optical components for optical fiber H₂O sensing system

Measurement and analysis of water vapor inside optical components for optical fiber H₂O sensing system

Optical humidity sensor based on air guided photonic crystal fiber

Multi-Channel Optical Fiber Methane Monitoring System Based on Laser Absorption Spectroscopy

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Measurement technique for methane concentration by wavelength scanning of a distributed-feedback laser

Cited by 17 publications

References 6 publications

Measurement and analysis of water vapor inside optical components for optical fiber H2O sensing system

Measurement and analysis of water vapor inside optical components for optical fiber H2O sensing system

Optical humidity sensor based on air guided photonic crystal fiber

Multi-Channel Optical Fiber Methane Monitoring System Based on Laser Absorption Spectroscopy

Contact Info

Product

Resources

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Measurement and analysis of water vapor inside optical components for optical fiber H₂O sensing system

Measurement and analysis of water vapor inside optical components for optical fiber H₂O sensing system