Simulation of a localized surface-plasmon-resonance-based fiber optic temperature sensor.

A fiber optic temperature sensor based on localized surface plasmon resonance of spherical gold nanoparticles embedded in a dielectric layer around the unclad core of a small portion of the fiber has been analyzed. Simulations have been carried out for a number of dielectric materials that show considerable changes in their refractive indices due to a change in the temperature in addition to having refractive indices higher than that of the fiber core. The analysis is based on the spectral interrogation method. The surface plasmons in metal nanoparticles have been excited by the light refracted through the core and the dielectric interface. The sensitivity of the sensor has been determined for each dielectric material used, and it is found to be the maximum for CdGeP(2) as a sensing medium. The temperature sensing range of the present sensor is also wide because the melting points of the metal and the fiber core, as well as the sensing medium, are large. The proposed fiber optic temperature sensor is compact, light weight, and highly sensitive with a wide temperature sensing range.