Simultaneous measurement of current and temperature by using an all-fiber interferometric cost-effective and non-destructive sensing scheme

A single-mode single fiber Mach-Zehnder interferometer is fabricated and employed for simultaneous measurement of temperature and direct current flowing through the resistor without disturbing the electronic circuit. The all-fiber interferometric sensing scheme is completely non-destructive, cost-effective and relies on change in heat induced fringe pattern of the Mach-Zehnder interferometer placed near the direct current carrying power resistor. The values of the sum of the modal thermo-optic coefficient and thermal expansion coefficient and other thermal properties of the optical fiber are also estimated. The optical and electrical methods proposed herein are found to be repeatable and provides stable results. The scheme predicts reasonable accurate values of the temperature and direct current with the root mean square errors of 0.45 and 0.00084, respectively.