Analytical Investigation of Phase Detuning Induced Transparency in Multi-Ring Cascaded Filters

We propose a novel control strategy that introduces a transparent off-state in cascaded multistage filtering structures based on MicroRing Resonator elements. These are fundamental elements in integrated photonics and represent a widespread filtering solution, especially in higher-order structures, which allows the synthesis of high-performance filters. We showcase the effect that thermal control can have in such configurations to enable a transparent bar-state, suppressing the main resonant peaks. This effect is analyzed by assuming phase control over the rings compatible with the traditional thermal calibration setup implemented on such devices.