Performance enhancement of optical sensors using long period fiber grating

Abstract

In recent years, long period fiber grating (LPFG) has been demonstrated as the most important fiber-optic device for numerous sensing applications. Various characteristics of LPFG make it attractive in the measurement of temperature, strain, bending radius, external index of refraction etc. This proposed work explores the feasibility of utilizing LPFG for temperature and strain sensitivity enhancement. Basically, the shift in resonant wavelength of LPFG depends on thermo-optic and strain-optic effect. By enhancing these effects using optimization of thermo-optic and strain-optic parameters, both resonant wavelength shift and sensitivity can be increased. Using this concept sensitivity of 19.32nm/oc for temperature range 25oc to 140oc and sensitivity of 53.2pm/με for strain range 0με to 38000με is achieved in this work.