Comparative study of coupling to symmetric and antisymmetric cladding modes in long-period fiber gratings

Abstract

ABSTRACTWe analyse the influence of coupling to symmetric and antisymmetric cladding modes in arc-induced Long-Period Fiber Gratings for temperature and strain sensing. The origin of this difference in energy coupling is related to the fabrication process of these gratings and depends on the electric arc discharge conditions, which modulates the refractive index and geometry of the optical fiber. Finally, results demonstrate the performance of different cladding modes excited in arc-induced LPFGs to temperature and strain applications and, in addition, indicate which coupling might be appropriate to certain sensing applications.