Generalised analysis of double-coupler doubly-resonant optical circuit

A generalised analysis of doubly-resonant ring resonators using a double-coupler structure with optical feedback paths, in which lightwaves travelling in opposite directions are coupled with reverse-wave feedback optical waves, is described. The double-coupler doubly-resonant optical circuits are shown to exhibit unique resonant characteristics, with the resonance degeneration coincidentally leading to a significantly sharp optical pass or depleted band for narrow bandpass or notch filtering respectively. Pole and zero patterns of the transmitted and reflected output transfer functions are used to analyse the resonance and interference of the resonator. Thus tunable and switchable optical resonators are proposed