Improvement in temperature sensitivity of FBG by coating of different materials

This paper presents the simulation results of coated Fiber Bragg Grating (FBG) as temperature sensor. As we know that bare FBG cannot be used as temperature sensor because they are made of silica and the thermal expansion coefficient of silica is very less. Hence bare FBG is less sensitive to temperature variation. To enhance the temperature sensitivity of the FBG sensor different types of materials are coated on FBGs whose thermal expansion coefficients are greater than that of silica. In this simulation Lead, Indium, Copper, Aluminium, and PMMA are coated on FBG and the simulation results are compared with the previous experimental work for the temperature range 50 K – 300 K. PMMA coated FBG sensor showed best sensitivity value among above coating materials.