Amplitude-assisted fitting demodulation for Sub-spatial-resolution field reconstruction in Raman distributed fiber...

Area of Science:

• Fiber Optic Sensing
• Temperature Measurement
• Signal Processing

Background:

• Conventional Raman distributed fiber optic sensing (RDTS) faces limitations in achieving high-precision measurements at sub-spatial scales due to its reliance on optical time-domain reflectance positioning.
• Existing methods struggle with accuracy in small spatial resolution zones, hindering detailed temperature profiling.

Purpose of the Study:

• To develop a high-precision temperature demodulation scheme for RDTS systems.
• To overcome the sub-spatial resolution limitations of conventional RDTS.
• To improve the accuracy of distributed temperature field reconstruction.

Main Methods:

• A novel amplitude-assisted fitting scheme is proposed.
• A three-dimensional mathematical model is constructed to establish a linear relationship between temperature and amplitude auxiliary parameters.
• The model is used to correct distorted temperature profiles and reconstruct the distributed temperature field.

Main Results:

• The method significantly increases temperature measurement accuracy in sub-spatial resolution zones.
• Experimental validation shows accuracy improved from 26 °C to 2.58 °C in a 50 cm zone over a 20 km sensing distance.
• The technique overcomes physical resolution limitations via signal processing without hardware changes.

Conclusions:

• The proposed amplitude-assisted fitting scheme offers a high-precision temperature demodulation solution for RDTS.
• This method provides a simple, engineerable approach to enhance RDTS performance, overcoming resolution limitations.
• It presents a new technical pathway for optimizing RDTS systems without complex algorithms or hardware modifications.