Investigation on an ultra-compact 1\times 2 polymer electro-optic switch using cross-coupling 2N+1 vertical-turning serial-coupled microrings

Generic model and thorough investigation are proposed for a novel $1\times 2$ 1 × 2 polymer electro-optic (EO) switch based on one-group $2N+1$ 2 N + 1 vertical-turning serial-coupled microrings. For realizing boxlike flat spectrum as well as low crosstalk and insertion loss, resonance order and coupling gaps are optimized. The MRR switches with $N \ge 1$ N ≥ 1 reveal favorable boxlike spectrum as when compared with the simple device with only one microring ( $N = 0$ N = 0 ). For obtaining $<-30\,\text{ dB }$ < - 30 dB crosstalk under through-state, the dependency of switching voltage on $N$ N is determined as $7.19 \times \text{ exp }(-N/0.72) + 1.72\,(\text{ V })$ 7.19 × exp ( - N / 0.72 ) + 1.72 ( V ) . Under the operation voltages of 0 V (drop state) and the predicted switching voltages (through state), the device performances are analyzed, and $1 \le N \le 10$ 1 ≤ N ≤ 10 is required for dropping the insertion loss (drop state) below 10 dB. The crosstalk of the ten devices ( $N = 1-10$ N = 1 - 10 ) are $< -19.5\,\text{ dB }$ < - 19.5 dB under drop state and $< -28.7\,\text{ dB }$ < - 28.7 dB under through state, and the insertion losses of the devices ( $N = 1-10$ N = 1 - 10 ) are $< 9.715\,\text{ dB }$ < 9.715 dB under drop state and $< 1.573\,\text{ dB }$ < 1.573 dB under through state. The device also has ultra-compact footprint size of only 0.33–1.06 mm, which is only 1/10–1/3 of those of our previously reported polymer EO switches based on directional coupler or Mach–Zehnder interferometer structures. Therefore, the proposed device is capable of highly integration onto optical networks-on-chip.