Discrimination between strain and temperature by cascading single-mode thin-core diameter fibers

Area of Science:

• Photonics and Optical Sensing
• Fiber Optic Technology
• Interferometry

Background:

• Accurate simultaneous measurement of temperature and strain is crucial in various engineering applications.
• Existing fiber-optic sensors often face challenges in discriminating between these two parameters due to cross-sensitivity.

Purpose of the Study:

• To propose and experimentally demonstrate a simple fiber-optic sensor for simultaneous and independent measurement of temperature and strain.
• To leverage the differential responses of cascaded inter-modal interferometers (IMIs) for dual-parameter sensing.

Main Methods:

• Fabrication of a sensor head by cascading two sections of single-mode thin-core diameter fibers (TCFs).
• Utilizing two distinct IMIs within the TCFs, each exhibiting unique sensitivities to strain and temperature.
• Monitoring resonant wavelength shifts to differentiate between temperature and strain effects.

Main Results:

• The sensor achieved a strain resolution of 37.41 με and a temperature resolution of 0.732 °C.
• Sensing sensitivities were measured as -1.03 pm/με for strain and 30.74 pm/°C for temperature.
• Experimental validation was performed within a strain range of 0-1333.3 με and a temperature range of 26.9 °C to 61.7 °C.

Conclusions:

• The proposed fiber-optic sensor effectively discriminates between temperature and strain using cascaded IMIs.
• The sensor offers advantages of easy fabrication, low cost, and high sensitivity.
• This technology shows significant potential for dual-parameter measurement applications.