Remote methane sensor using raman amplified open path TDLS

D.M. Mitchell, K. Duffin, W. Johnstone

Research output: Contribution to conferencePaper

11 Citations (Scopus)


Reported here is a long-range optical methane sensor designed with the purpose of enabling more efficient leak monitoring of natural gas pipelines, oil rigs and gas containers including ships. Combining sensitive Wavelength Modulation Spectroscopy (WMS) and a high power Raman amplifier system, the sensor launches a high power 1650.95nm signal at an inspection
site at a distance of around 100m and analyses the backscatter via a large Fresnel lens to detect methane concentrations of 100ppm in a 1m gas cloud up to 100%. The work comprises the design and testing of a low-noise high-power fibre Raman amplifier system as a remote methane sensing source. Seeded by a single-mode 1650.95nm laser (DFB), upon which the WMS modulation is applied, the Raman amplifier produces a highpower, narrow-band methane sensing signal. Key to the system’s competitive advantage is its low cost, small size, low weight, high reliability and superior performance when compared
to bulk long-range airborne systems. This results from designing a fibre based system that is constructed entirely from standard communications fibre and components. Lab trials at 11m have been conducted and show by extrapolation that a 1m cloud of methane at a concentration of 100ppm can be detected with a signal to noise ratio of 3:1 at a range of >100m.
Original languageEnglish
Number of pages1
Publication statusPublished - Jul 2009
Event7th International Conference on Tunable Diode Laser Spectroscopy - Zermatt, Switzerland
Duration: 13 Jul 200917 Jul 2009


Conference7th International Conference on Tunable Diode Laser Spectroscopy
CityZermatt, Switzerland


  • optical methane sensor
  • wavelength modulation spectroscopy
  • raman amplifier
  • yunable diode laser spectroscopy


Dive into the research topics of 'Remote methane sensor using raman amplified open path TDLS'. Together they form a unique fingerprint.

Cite this