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By using poled-polymer/silicon slot waveguides in the active region and employing the Pockels effect of the poled-polymer, we propose a kind of Mach–Zehnder interferometer (MZI) electro-optic (EO) switch operated at 1550 nm. Dependencies of switching characteristics versus the slot waveguide parameters are investigated, including EO overlap integral, power ratio confined in the slot, and voltage-length product. Given the dimension of the silicon strip of 190 × 300 nm, as the slot width varies within 50–100 nm, the switching voltage can be as low as 1.0 V with only 0.17–0.35 mm active region length, and the whole device length is only about 770–950 μm. For the switch with 50 nm slot width, the insertion loss is about 4.42 dB under both operation states, and the crosstalk under cross-state and that under bar-state are about −48.2 and −65.3 dB, respectively. An impressive advantage of this switching structure lies that the voltage-length product (0.17–0.35 V mm) is at least 19–40 times smaller than that of the traditional polymer MZI EO switch (6.69 V mm). Compared with our previously reported two kinds of MZI or microring resonator assisted MZI EO switches, this switch does exhibit some superior characteristics, including low switching voltage, compact device size and small wavelength dependency, due to the use of slot waveguides in the MZI EO region.

Universal structure and thorough analysis were proposed for a kind of polymer optical switch using N-th order microring resonator side-coupled Mach–Zehnder interferometer (MRR-SC-MZI). Formulation and expression of output power, insertion loss and crosstalk were derived, and detailed design and optimization were carried out. Analytical results indicate that all devices for N≥1 can perform normal switching function, and 8≥N≥2 is preferred for dropping the driving voltage below 5 V. For the seven MRR-SC-MZI EO switches (N=2–8) whose cross-state voltages are within 0–2.32 V, their bar-state voltages are within 0.96–4.83 V and their insertion losses are within 0.35–0.85 dB at bar state, whereas those within 0.14–1.70 dB at cross state; their crosstalk are within −20.79 to −31.11 dB at bar state, whereas those are within −13.86 to −20.36 dB at cross state; their 3-dB electrical bandwidths are within 18.5–28.0 GHz, and 3-dB optical bandwidths for the two output ports are within 18.1–40.0 GHz and 32.0~55 GHz, respectively. Comparison indicates that the driving voltages of the proposed MRR-SC-MZI switching devices are 10–250 times smaller than those of the traditional MZI EO switches with the same EO region length, device length and structural parameters. Therefore, due to small footprint size and low driving voltage, this switching configuration can be densely integrated onto optoelectronic chips.

Universal structure and thorough analysis are proposed for a kind of (2N + 1)th order polymer microring resonator Mach–Zehnder interferometer (MRR-MZI) electro-optic (EO) switch. Formulas and expressions of output power, insertion loss and crosstalk are derived, and detailed design and optimization are carried out. Analytical results indicate that, besides the first-order MRR-MZI EO switch (N = 0), other devices for N ≥ 1 can all perform normal switching function, and 5 ≥ N ≥ 2 is preferred for dropping the crosstalk below −10 dB. For the four MRR EO switches (N = 2–5), their switching voltages are 0.99, 0.73, 0.57 and 0.47 V, respectively; their insertion losses are within the range of 1.15–2.26 dB at bar state, whereas those are within the range of 1.95–2.42 dB at cross state; their crosstalks are within the range of 11.04–17.82 dB at bar state, whereas those are within the range of 10.34–12.51 dB at cross state. Compared with the traditional MZI EO switch, the voltage–length product (0.21 V mm) of this switching element is decreased by ~111.7 times under the same waveguide parameters. Therefore, due to small footprint size and extremely low switching voltage, this switching configuration can be densely integrated onto optoelectronic chips.

A novel 1×2 polymer electro-optic (EO) switch based on seven vertical-turning serial-coupled microrings is proposed for dropping crosstalk and obtaining flat boxlike spectrum. The device structure, theory and formulation are presented, and the microring resonance order and coupling gaps are optimized. The switching voltage of the device for obtaining crosstalk lower than −30 dB under through state is decided to be about 1.86 V. Under the operation voltages of 0 V (drop state) and 1.86 V (through state), the switching performance is characterized, and the output spectrum is analyzed. The calculation results show that the crosstalk at through state and that at drop state are −30.2 dB and −53.2 dB, respectively, while the insertion losses are 0.86 dB and 3.18 dB, respectively. Owning to the seven serial-coupled microrings resonance structure, the proposed switch reveals the favorable boxlike spectrum compared with the simple device with only one microring, and thus the crosstalk under drop state is improved from −26.8 dB to −53.2 dB. Due to the low crosstalk, this device can be used in optical networks-on-chip for signal switching and routing.

Based on different basic routing elements, device architectures and design schemes of three kinds of four-port optical routers with the same routing function are studied. First, the structural parameters of the routing elements including cross-coupling one microring resonator (CCO-MRR), cross-coupling two microring resonators (CCT-MRR) and parallel-coupling one microring resonator (PCO-MRR), are optimized for single-mode transmission, low optical loss and phase-match between microring waveguide and channel waveguide. Then, detailed routing topologies of the three routers are presented, and a thorough comparison among them is made on their routing performances. The used MRR numbers of the CCO-MRR-based and PCO-MRR-based routers (four rings) are half of that of the CCT-MRR-based router (eight rings); the PCO-MRR-based router depicts the minimum insertion loss (0.02–0.6 dB); the CCT-MRR-based router reveals the minimum crosstalk (