Integrated hybrid Raman/fiber Bragg grating interrogation scheme for distributed temperature and point dynamic strain...

Area of Science:

• Fiber Optic Sensing
• Integrated Photonics
• Distributed Sensing

Background:

• Traditional fiber optic sensing often relies on separate systems for distributed and point measurements.
• Integrating different sensing modalities can enhance efficiency and reduce system complexity.
• Accurate simultaneous measurement of temperature and dynamic strain is crucial in many industrial applications.

Purpose of the Study:

• To propose and demonstrate an integrated hybrid optical fiber sensing technique.
• To combine distributed Raman-based temperature sensing with fiber Bragg grating (FBG)-based dynamic strain measurements.
• To achieve simultaneous, high-resolution, and temperature-independent strain measurements alongside distributed temperature sensing.

Main Methods:

• Utilized a common optical source/receiver block for a highly integrated system.
• Employed multimode fiber for distributed temperature sensing.
• Used pairs of partially spectrally overlapped fiber Bragg gratings (FBGs) for temperature-independent discrete strain measurements.

Main Results:

• Achieved a dynamic strain resolution of 7.8 nε/√Hz over a 1700 με range.
• Demonstrated a distributed temperature resolution of 1°C at a 20 km distance.
• Reported a spatial resolution of 2.7 m for temperature sensing.

Conclusions:

• The proposed integrated hybrid optical fiber sensing technique is feasible and efficient.
• The system successfully combines distributed temperature and discrete strain sensing with high performance.
• This approach offers a versatile solution for simultaneous environmental monitoring and structural health assessment.