Analysis and design of box-like filters based on 3×2 microring resonator arrays

This paper theoretically investigates spectral characteristics of the 3×2 microring resonator array, with its analytical model developed firstly. Simulation results show that the case of the ring-bus coupling coefficient smaller than the ring-ring coupling coefficient is suitable for box-like filters. After design principles are given, the optimization process are carried out by evaluating the side lobe rejection ratio, the passband ripple rejection ratio and the roll-off coefficient of the passband edge. The FWHM of the designed box-like filter can be adjustable in a flexible range.