Interrogation of SMS for measuring of temperature and strain using half-etched FBG with enhanced sensitivity

In this paper, a method for interrogation of Fibre Bragg Grating (FBG) and single mode-multimode-single mode (SMS) fiber for simultaneous measurement of temperature and strain using is proposed and demonstrated. A half etched FBG is deployed in the optical circuitry for sensitivity enhancement. The sensor exhibits the temperature and strain sensitivity of 20.2 pm/°C and 1.91 pm/μe over the range of 20-200 °C and 100-2020 μe respectively. The resolution for temperature and strain measurement is ±0.5 °C and ±12 μe. The experimental results show that the sensor is able to measure strain and temperature simultaneously by sensitivity matrix with additional advantages such as simple structure, compact size, ease of fabrication, and low cost.