Ultra-High-Contrast and Tunable-Bandwidth Filter Using Cascaded High-Order Silicon Microring Filters

High-contrast optical filtering is demonstrated using cascaded silicon microrings. We report an experimental measurement of a record 100 dB pass-band to stop-band contrast, tunable 12–125 GHz passband full-width at half-maximum, band-center insertion loss ripple${<}{3}~{\rm dB}$, and a group delay ripple${<}{5}~{\rm ps}$, using transverse electric polarized light.