Fiber optic temperature and strain sensor using dual Mach-Zehnder interferometers

Area of Science:

• Photonics
• Optical Sensing
• Fiber Optics

Background:

• Accurate simultaneous measurement of temperature and strain is crucial in many engineering applications.
• Existing fiber optic sensors often face limitations in resolution or fabrication complexity.

Purpose of the Study:

• To propose and experimentally validate a novel fiber optic sensor capable of simultaneous temperature and strain measurement.
• To demonstrate the sensor's performance using dual Mach-Zehnder interferometers (MZIs).

Main Methods:

• Fabrication of dual MZIs by fusion splicing a thin-core fiber and a small-cladding polarization-maintaining fiber between single-mode fibers with core offset.
• Utilizing the distinct responses of the two MZIs to temperature and strain.
• Experimental validation by selecting two resonant dips in the transmission spectrum to construct a measurement matrix.

Main Results:

• The proposed sensor achieved a maximum temperature sensitivity of 66.67 pm/°C and a maximum strain sensitivity of -2.0 pm/µε.
• Demonstrated minimum discriminated temperature and strain values of 0.20°C and 0.71 µε for one MZI, and 0.33°C and 0.69 µε for the other.
• Successful simultaneous measurement of temperature and strain was experimentally validated.

Conclusions:

• The developed dual MZI fiber optic sensor enables accurate and simultaneous measurement of temperature and strain.
• The sensor exhibits excellent sensitivity and resolution, making it suitable for practical applications.
• Ease of fabrication, low cost, and good resolution present promising application prospects for this sensor technology.