Generic design and analysis of an ultra-compact polymer electro-optic switch using two-group 2N+1 vertical-turning serial-coupled microrings

Universal model and investigation are proposed for a novel 2×2 polymer electro-optic (EO) switch based on two-group 2N+1 vertical-turning series-coupled microrings. For realizing boxlike spectrum (drop port) as well as low crosstalk and insertion loss, resonance order and coupling gaps are optimized. The microring resonator (MRR) switches with N≥1 reveal favorable boxlike flat spectrum as when compared with the simple device with only one microring (N=0), and 1≤N≤5 is required for obtaining <∼5 dB insertion loss under cross state (U=0 V). For the five MRR switches (N=1-5), the free-spectrum range (FSR) is ∼12 nm (∼1500 GHz), the switching voltage is about 4.0 V, their crosstalk are <−51 dB under cross state and <−28.2 dB under bar state, and their insertion losses are <5.12 dB under cross state and <0.24 dB under bar state. The devices also have ultra-compact footprint size of 0.325-0.652 mm, which is only 1/10-1/5 of those of our previously reported polymer EO switches based on directional coupler (DC) or Mach-Zehnder interferometer (MZI) structures. Consequently, the proposed switching element can be highly integrated onto optoelectronic chips for constructing large switching arrays.