In order to characterize electro-optic polymer modulators, a full-vectorial finite-difference mode solver has been developed to solve Maxwell's equation for an optical waveguide, and a finite-element method has been employed to analyze a microwave electrode. A systematic and detailed discussion has been presented to describe and design a modulator about performance parameters: $V_{\pi}L,\Delta fL, N_{m}, \alpha_{c}$, and $z_{c}$ with all the necessary design parameters: optical waveguide (width and height), electrode (width and height), and thickness of cladding layer. We can see that most of the results are interesting, even very different from general opinions, for example, one can observe that $V_{\pi}L$ is not always reduced with an increased width of optical waveguide. These will be helpful for an optimized design of a modulator.

Optical waveguides on three material platforms of silicon-on-insulator (SOI), amorphous silicon (a-Si:H) and silicon nitride are analyzed for realization of an optical compact link compatible with CMOS technology. The three material properties are presented. The optical components on the three potential material platforms are put together for a comparison, in which, straight, bent waveguides, and multimode-interference beam splitters for an optical link are designed, fabricated, and measured. The comparison results of simulation and measurement show that a-Si:H has a similar performances with SOI material but lower cost and good feasibility of photonic integration on silicon.

In order to improve the coupling coefficient between a bus waveguide and a bent waveguide of an ultracompact microring to obtain the critical coupling, a design using a bent bus waveguide with reduced width is provided to maintain a better phase matching and increase the coupling. A full vectorial finite difference model, specifically suited for high index contrast and smaller size waveguides, for example, a waveguide in the silicon-on-insulator (SOI) technology, is developed. As a validation, the straight and bent waveguides are simulated using this model, whose results are compared with the results deduced from the measurement results of the ultracompact ring resonators in SOI technology. Also, the model solver is performed to simulate the design, and an experiment is implemented to testify the design.

A novel process to control light through the coupling modulation by surface acoustic wave (SAW) is presented in an optical micro resonator. An optical waveguide modulator of a racetrack resonator on silicon-on-insulator (SOI) technology is took as an example to explore the mechanism. A finite-difference time-domain (FDTD) is developed to simulate the acousto-optical (AO) modulator using the mechanism. An analytical method is presented to verify our proposal. The results show that the process can work well as an optical modulator by SAW.

In this paper, we develop an analytical model of an integrated acousto-optical (AO) device with arms modulated by a single surface acoustic wave beam. A comparison between one-arm and two-arm modulation is presented, which shows that two-arm modulation can significantly enhance modulation efficiency by an optimized design. A detailed analysis of the influence of static phase difference on the behavior of the AO devices has been provided, and some interesting results have been obtained. These will be helpful for an optimized design of AO devices for different functionalities.