Strain and temperature sensor using few-mode fiber, designing guidelines and results

Strain and temperature sensing based on mode interference in a few-mode fiber is analyzed theoretically and experimentally. The effect of using different mode combinations is explored. A fiber guiding four LP modes is investigated as an example. Good agreement between modeling and experimental results is found for strain sensor. We demonstrate the sensors feasibility by measuring strain ranging from 0 mm to 16 mm with a sensitivity of 3.43 nm/mm and measuring temperature ranging from 30 °C to 100 °C with a sensitivity of 4.8 pm/°C.