Strain sensor based on gourd-shaped single-mode-multimode-single-mode hybrid optical fibre structure

Area of Science:

• Photonics and Optical Sensing
• Fiber Optic Sensors
• Interferometry

Background:

• Fiber-optic sensors offer high sensitivity and immunity to electromagnetic interference.
• Fabry-Perot interferometers (FPIs) are widely used for sensing applications.
• Developing compact and highly sensitive FPI-based sensors remains an active research area.

Purpose of the Study:

• To design and experimentally validate a novel fiber-optic strain sensor.
• To investigate the strain sensing performance of a gourd-shaped multimode fiber (MMF) structure.
• To explore the cross-sensitivity of the sensor to temperature and humidity.

Main Methods:

• Fabrication of a gourd-shaped joint using an electrical arc method to fuse two single-mode fibers (SMFs) with an MMF.
• Formation of a Fabry-Perot cavity within the multimode inter-fiber section.
• Experimental characterization of strain, temperature, and humidity sensing capabilities.

Main Results:

• The gourd-shaped FPI sensor demonstrated a high strain sensitivity of -2.60 pm/με.
• The sensor operated effectively over a strain range of 0-1000 με.
• Initial investigations into temperature and humidity cross-sensitivity were conducted.

Conclusions:

• The proposed gourd-shaped MMF-based FPI sensor is a viable and highly sensitive platform for strain measurement.
• The fabrication method is effective in creating a robust sensing structure.
• Further research is needed to fully understand and mitigate cross-sensitivities for practical applications.