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Applied Optics

Applied Optics


  • Vol. 40, Iss. 7 — Mar. 1, 2001
  • pp: 1011–1020

Multiplexing of optical fiber gas sensors with a frequency-modulated continuous-wave technique

H. B. Yu, W. Jin, H. L. Ho, K. C. Chan, C. C. Chan, M. S. Demokan, G. Stewart, B. Culshaw, and Y. B. Liao  »View Author Affiliations

Applied Optics, Vol. 40, Issue 7, pp. 1011-1020 (2001)

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We report on the use of a frequency-modulated continuous-wave technique for multiplexing optical fiber gas sensors. The sensor network is of a ladder topology and is interrogated by a tunable laser. The system performance in terms of detection sensitivity and cross talk between sensors was investigated and found to be limited by coherent mixing between signals from different channels. The system performance can be improved significantly by use of appropriate wavelength modulation–scanning coupled with low-pass filtering. Computer simulation shows that an array of 37 acetylene sensors with a detection accuracy of 2000 parts in 106 for each sensor may be realized. A two-sensor acetylene detection system was experimentally demonstrated that had a detection sensitivity of 165 parts in 106 for 2.5-cm gas cells (or a minimum detectable absorbance of 2.1 × 10-4) and a cross talk of -25 dB.

© 2001 Optical Society of America

OCIS Codes
(060.2370) Fiber optics and optical communications : Fiber optics sensors
(060.2630) Fiber optics and optical communications : Frequency modulation
(060.4230) Fiber optics and optical communications : Multiplexing
(300.1030) Spectroscopy : Absorption
(300.6340) Spectroscopy : Spectroscopy, infrared
(300.6380) Spectroscopy : Spectroscopy, modulation

Original Manuscript: May 19, 2000
Revised Manuscript: August 24, 2000
Published: March 1, 2001

H. B. Yu, W. Jin, H. L. Ho, K. C. Chan, C. C. Chan, M. S. Demokan, G. Stewart, B. Culshaw, and Y. B. Liao, "Multiplexing of optical fiber gas sensors with a frequency-modulated continuous-wave technique," Appl. Opt. 40, 1011-1020 (2001)

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  1. G. Stewart, “Fibre optic sensors,” in Sensor Technologies, Vol. 1 of Sensor Systems for Environmental Monitoring, M. Campbell, ed. (Chapman & Hall, London, 1997), Chap. 1, pp. 1–40.
  2. J. P. Dakin, C. A. Wade, D. Pinchbeck, J. S. Wykes, “A novel optical fibre methane sensor,” J. Opt. Sensors 2, 261–267 (1987).
  3. K. Chan, H. Ito, H. Inaba, T. Furuya, “10 km-long fiber optic remote sensing of CH4 gas by near infrared absorption,” Appl. Phys. B 38, 11–15 (1985). [CrossRef]
  4. D. M. Bruce, D. T. Cassidy, “Detection of oxygen using short external cavity GaAs semiconductor diode lasers,” Appl. Opt. 29, 1327–1332 (1990). [CrossRef] [PubMed]
  5. D. B. Oh, D. C. Hovde, “Wavelength-modulation detection of acetylene with near-infrared external-cavity diode laser,” Appl. Opt. 34, 7002–7005 (1995). [CrossRef] [PubMed]
  6. X. Zhu, D. T. Cassidy, “Electronic subtracter for trace-gas detection with InGaAsP diode laser,” Appl. Opt. 34, 8303–8308 (1995). [CrossRef] [PubMed]
  7. J. A. Silver, “Frequency-modulation spectroscopy for trace species detection: theory and comparison among experimental methods,” Appl. Opt. 31, 707–717 (1992). [CrossRef] [PubMed]
  8. D. S. Bomse, A. C. Stanton, J. A. Silver, “Frequency-modulation and wavelength modulation spectroscopies: comparison of experimental methods using a lead-salt diode laser,” Appl. Opt. 31, 718–731 (1992). [CrossRef] [PubMed]
  9. W. Jin, Y. Z. Xu, M. S. Demokan, G. Stewart, “Investigation of interferometric noise in fiber-optic gas sensors with use of wavelength modulation spectroscopy,” Appl. Opt. 36, 7239–7246 (1997). [CrossRef]
  10. J. Reid, D. Labrie, “Second-harmonic detection with tunable diode lasers—comparison of experiment and theory,” Appl. Phys. B 26, 203–210 (1981). [CrossRef]
  11. B. F. Ventrudo, D. T. Cassidy, “Operating characteristics of a tunable diode laser absorption spectrometer using short-external-cavity and DFB laser diodes,” Appl. Opt. 29, 5007–5013 (1990). [CrossRef] [PubMed]
  12. Y. Shimose, T. Okamoto, A. Maruyama, M. Aizawa, H. Nagai, “Remote sensing of methane gas by differential absorption measurement using a wavelength-tunable DFB LD,” IEEE Photon. Technol. Lett. 3, 86–87 (1991). [CrossRef]
  13. G. Stewart, C. Tandy, D. Moodie, M. A. Morante, F. Dong, “Design of a fiber optic multipoint sensor for gas detection,” Sensors Actuators B 51, 227–232 (1998). [CrossRef]
  14. W. Jin, “Performance analysis of a time-division-multiplexed fiber-optic gas-sensor array by wavelength modulation of a distributed-feedback laser,” Appl. Opt. 38, 5290–5297 (1999). [CrossRef]
  15. J. P. Dakin, “Multiplexed and distributed optical fiber sensors,” J. Phys. E 20, 954–967 (1987). [CrossRef]
  16. J. L. Brooks, B. Moslehi, B. Y. Kim, H. J. Shaw, “Time-domain addressing of remote fiber-optic interferometric sensor arrays,” J. Lightwave Technol. LT-5, 1014–1023 (1987). [CrossRef]
  17. P. K. C. Chan, W. Jin, J. M. Gong, M. S. Demokan, “Multiplexing of fiber Bragg grating sensors using an FMCW technique,” IEEE Photon. Technol. Lett. 11, 1470–1472 (1999). [CrossRef]
  18. P. K. C. Chan, “Multiplexing of fiber optic bragg grating sensors,” Ph.D. dissertation (Hong Kong Polytechnic University, Hong Kong, 2000).
  19. H. Riris, C. B. Carlisle, R. E. Warren, D. E. Cooper, “Signal-to-noise ratio enhancement in frequency-modulation spectrometers by digital signal processing,” Opt. Lett. 19, 144–146 (1994). [CrossRef] [PubMed]
  20. C. C. Chan, “Interrogation of fiber Bragg grating sensors with a tunable laser,” Ph.D. dissertation (Hong Kong Polytechnic University, Hong Kong, 2000).
  21. W. R. Philp, W. Jin, A. Mencaglia, G. Stewart, B. Culshaw, “Interferometric noise in frequency modulated optical gas sensors,” in Proceedings of Twenty-First Australian Conference on Optical Fibre Technology (Institute of Radio and Electronics Engineers Society, Milsons Point, Australia, 1986), pp. 185–188.

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