Resonance conditions of long-period gratings in temperature sensitive polymer ring optical fibers

Recently a novel optical fiber with a temperature sensitive polymer ring and long-period grating has been experimentally produced and studied. We present here results from a finite-element based simulation of such a structure. The numerically determined resonance conditions for varying temperature show similar behavior to previously reported experimental results. We predict for the first time, as far as the authors are aware, that it is possible for this type of fiber to exhibit dual resonance conditions and as a consequence suffer band rejection broadening.