Attenuation Based Passive Fiber Optic Sensor – Characterization of Refractive Index at Wide Range of Temperatures Using a Tunable Light Source
The study of refractive index is a topic of growing interest across the worlddue to their applications in numerous fields, ranging from consumer uses to the food, chemical, fragrant, military, medicine, beverages, bio-chemical, petro-chemical, pharmaceutical industries, etc. Many of the drawbacks found in conventional sensors were overcome by the use of optical fiber sensors operating at a new setof properties. The optical fiber sensors with their advantages such as low attenuation, light in weight, possibility of multiplexing, passive nature, immunity to EMI and RFI among others these sensors are alternative to electronic sensors. In the present work an evanescent wave absorption based fiber optic refractive index sensor operating at various wavelengths (630nm, 660nm, 820nm and 850nm) and at wide range of temperatures (10oC to 60oC) has been analyzed. The study of the sensor is taken up using two volatile liquid mixtures such as Toluene and Methanol as the liquid cladding in the region of sensing. By implementing the present sensor, the refractive index of any unknown liquid can be measured, whose value lies in the dynamic range between 1.305nD to 1.509nD, temperature range of 10oC to 60oC and using the various wavelengths of 630nm, 660nm, 820nm and 850nm.