Characteristics of ultra-compact polymer modulators based on silicon photonic crystal ring resonators

Ultra-compact polymer modulators were proposed and simulated, based on the hybrid integration of functional polymer materials with Si based photonic-crystal ring resonators (PCRRs). The simulations were carried out on device characteristics with an effective ring radius of 2.3 µm and tunable polymer index from 1.785 to 1.805. Investigating the loss, the cavity quality factor Q, and the free spectral range of such PCRRs, we found a 0.02 dB intrinsic loss that is independent of diameter, unlike the loss that varies inversely with diameter in microstrip resonators. Close to 100% drop efficiency at the drop channel of 1557.5 nm was obtained by design with a high spectral selectivity of Q greater than 1319 in the single-ring PCRR-based add-drop filters with ring radius of 1.2 µm.