Controlled Lattice-Hardening for Exceptionally Stable and Highly Efficient Organic Electro-Optic (EO) Materials toward Next Generation Optical Switches

Organic electro-optic (OEO) materials can effectively encode or decode an optical carrier wave with a high-speed electronic data signal. They provide very high modulation efficiency for the development of the next generation optical interconnects with large bandwidth, low power consumption, and cost-effective integration to address the issue of the dramatically increasing data rates. To facilitate the device fabrication, it is highly desirable to implement the well-established semiconductor processes of microelectronics to photonics devices. When applying these processes to photonic devices, the main challenge lies in the thermal stability of both the chemical composition and poling-induced acentric order of EO lattices. In addition to excellent longterm thermal stability at elevated temperatures (80-100 °C), satisfactory short-period stability at a temperature range greater than 250 °C is required. Thus, this dissertation is devoted to the research of seeking OEO materials with remarkable thermal stability and large EO coefficients as a valid near-term solution in chip-to-chip optical interconnects for tera-scale (terabits per second) computing. Herein, a very effective molecular engineering approach of reinforced site isolation has been systematically developed to increase thermal stability of highly polarizable dipolar chromophores. With this novel approach, we succeeded in prolonging the thermal and temporal alignment stability of organic EO materials up to 250 °C with large r33 values (>100 pm/V at the wavelengths of 1310 nm). The success of these material developments has inspired the exploration of new device concepts to take full advantage of organic EO materials with large r33 values.