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Updated: Jun 17, 2026
10:42
Infrared Degenerate Four-wave Mixing with Upconversion Detection for Quantitative Gas Sensing
Published on: March 22, 2019
Coherence-multiplexed FMCW spectroscopy for long-distance multi-point gas sensing
Optics Letters
|June 15, 2026
Summary
We developed a novel long-range gas-sensing technique using coherence multiplexing with optical frequency-modulated continuous-wave (FMCW) spectroscopy. This method significantly extends sensing distances for distributed gas monitoring applications.
Area of Science:
- Optoelectronics
- Spectroscopy
- Environmental Monitoring
Background:
- Traditional spectroscopic gas sensing faces limitations in range and spatial resolution.
- Distributed sensing requires robust methods to overcome signal degradation over long distances.
Purpose of the Study:
- To develop a long-range, multi-point spectroscopic gas-sensing method.
- To enhance the sensing distance and spatial resolution of optical frequency-modulated continuous-wave (FMCW) spectroscopy.
Main Methods:
- Incorporation of coherence multiplexing into FMCW spectroscopy.
- Segmentation of the sensing region to suppress phase noise accumulation.
- Segment-by-segment adjustment of optical delay for optimal coherence matching.
Main Results:
- Demonstrated multi-point acetylene gas sensing over 11 km.
- Achieved a minimum detectable concentration of 0.94 ppm and spatial resolution of 0.46 m.
- Extended the sensing range by a factor of 60 compared to conventional methods.
Conclusions:
- The proposed coherence-multiplexed FMCW spectroscopy offers a low-cost, high-capacity solution for long-distance distributed gas monitoring.
- The system relaxes requirements on laser coherence, detection bandwidth, and computing power.
- Potential to multiplex thousands of sensors with sufficient optical power budget.
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