Single Mode Optical Fiber based Refractive Index Sensor using Etched Cladding

The use of optical fiber for sensor applications is a topic of current interest. We report the fabrication of etched single mode optical fiber based refractive index sensor. Experiments are performed to determine the etch rate of fiber in buffered hydrofluoric acid, which can be high or low depending upon the temperature at which etching is carried out. Controlled wet etching of fiber cladding is performed using these measurements and etched fiber region is tested for refractive index sensing application. We report significant optical power change in fiber sensor at 1550 nm wavelength, in the presence of IPAsolution and also the sugar solution with varying concentration.