Sensitivity analysis of a fiber ring resonator based on an air-core photonic-bandgap fiber

The fiber ring resonator (FRR) is the core sensing element in a resonator fiber optic gyroscope (R-FOG), and its sensitivity determines the performance of the R-FOG. This paper presents an in-depth analysis of the sensitivity of the FRR which is made of an air-core photonic-bandgap fiber (PBF), in which the characteristics of the FRR using PBF are compared with that of an FRR using a conventional single mode fiber. When using PBF instead of conventional fiber, it is found that the resonance curve is changed, and the sensitivity of the FRR is decreased a little when a narrow spectral linewidth laser is used. However, the degree of the decrease in sensitivity is not big enough to deny the advantages of PBF in improving the performance of the R-FOG considering that PBF is much better than conventional fiber in reducing the drift. Also, the optimal parameters of the directional coupler for sensitivity are discussed. It is found that the optimal intensity coupling coefficient when using PBF is nearly two times larger than that when using conventional fiber, and the optimal coupler intensity loss when using PBF is smaller than that when using conventional fiber. (C) 2010 Elsevier Inc. All rights reserved.