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Updated: Jun 25, 2026
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Fiber Optic Distributed Sensors for High-resolution Temperature Field Mapping
Published on: November 7, 2016
Few-mode fiber based Raman distributed temperature sensing
Optics Express
|April 7, 2017
Summary
A new few-mode fiber (FMF) based Raman distributed temperature sensor (RDTS) extends sensing distance and improves signal-to-noise ratio (SNR). The quasi-single mode FMF allows higher pump power and mitigates differential mode group delay for enhanced temperature resolution.
Area of Science:
- Fiber optics
- Sensing technology
- Optical physics
Background:
- Raman distributed temperature sensing (RDTS) systems typically use standard single-mode fiber (SSMF).
- Multimode fiber (MMF) based RDTS systems suffer from differential mode group delay (DMGD), limiting performance.
- Enhancing signal-to-noise ratio (SNR) and extending sensing distance are key challenges in RDTS.
Purpose of the Study:
- To propose and demonstrate a few-mode fiber (FMF) based RDTS for extended sensing distance and improved SNR.
- To investigate the benefits of quasi-single mode (QSM) operation in FMFs for RDTS.
- To evaluate the performance and measurement uncertainty of FMF-based RDTS compared to SSMF.
Main Methods:
- Theoretical analysis of QSM operated FMFs considering geometric and optical parameters.
- Experimental demonstration using a 2-mode and a 4-mode FMF, compared with SSMF.
- Utilizing conventional RDTS hardware with a 30-ns, 1550nm pump pulse.
Main Results:
- The 2-mode FMF based RDTS demonstrated superior performance in longer distance measurements compared to SSMF and 4-mode FMF.
- Temperature resolutions of 10°C (SSMF), 7°C (4-mode FMF), and 6°C (2-mode FMF) were achieved at 20km distance.
- A 4°C improvement in temperature resolution was obtained using the 2-mode FMF over SSMF at the fiber end (3m spatial resolution, 80s measuring time).
Conclusions:
- Few-mode fibers, particularly 2-mode FMFs, offer significant advantages for Raman distributed temperature sensing.
- QSM operation in FMFs enhances SNR and extends sensing range by allowing higher pump power and mitigating DMGD.
- Fabrication imperfections and splicing losses in multi-mode FMFs can impact performance, making 2-mode FMFs a practical choice for enhanced RDTS.
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