Few-mode fiber multi-parameter sensor with distributed temperature and strain discrimination.

Area of Science:

• Optics and Photonics
• Fiber Optic Sensing
• Materials Science

Background:

• Distributed optical fiber sensors are crucial for real-time monitoring.
• Few-mode fibers (FMFs) offer potential for multi-parameter sensing.
• Distinguishing temperature and strain effects in optical fibers remains a challenge.

Purpose of the Study:

• To develop and demonstrate a multi-parameter optical-fiber sensor for simultaneous distributed temperature and strain measurement.
• To utilize the unique properties of few-mode fibers for enhanced sensing capabilities.
• To achieve accurate discrimination between temperature and strain using Brillouin frequency shift analysis.

Main Methods:

• A few-mode fiber (FMF) was employed as the sensing medium.
• A pump and probe signal were launched into specific linearly polarized modes within the FMF.
• Brillouin frequency shift (BFS) was monitored in the LP(01) and LP(11) modes.
• Temperature and strain coefficients of BFS were analyzed for discrimination.

Main Results:

• Successful discrimination between temperature and strain was demonstrated.
• The sensor achieved an accuracy of 1.2°C for temperature measurement.
• The sensor achieved an accuracy of 21.9 με for strain measurement.

Conclusions:

• The proposed FMF-based sensor effectively enables simultaneous distributed measurement of temperature and strain.
• Analysis of BFS in different fiber modes provides a robust method for parameter discrimination.
• This technology holds promise for advanced structural health monitoring and environmental sensing applications.