Analysis of four-port optical fiber ring and loop resonators usinga 3×3 fiber coupler and degenerate two-wave mixing

A theoretical analysis of four-port optical fiber ring and loop resonators using a 3×3 fiber directional coupler and degenerate two-wave mixing is presented. Expressions for the circulating (resonant) and output fields and intensities, as well as resonance conditions for two slightly different configurations of the loop resonator and for the ring resonator are obtained. It is found that the use of the degenerate two-wave mixing greatly improves the characteristics of these resonators. For example, the crosstalk of the ring or loop resonators when used as a wavelength division demultiplexer can be significantly deduced