Theoretical Comparison of Low- and High-splitting Ratio Resonators

There are two possible topologies to fabricate fiber optic resonators which contain a single, low-loss coupler. The first resonators reported in the literature were of the spliceless design and required a high splitting ratio coupler; they are denoted as a cross-coupled fiber resonator (CFR). The development of low-loss splicing technology enabled rings to be constructed from low splitting ratio couplers, which have been referred to as direct coupled resonators (DFR) in the literature. In this paper, DFR and CFR will be theoretically compared, using a matrix formalism implemented in MathematicaTM. Effects of a non optimum splitting ratio, differential normal mode losses, polarization cross-coupling, and backscatter will be examined. An optimum RFOG topology is suggested by this analysis. Presented at SPIE Photonics East Volume 2070, Pages 283-292 Boston 7-11 September 1993