The development of integrated photonics is limited by bulky and inefficient photonic component compared to their electronic counterparts due to weak light-matter interactions. As the key devices that determine the performance of integrated photonic circuits, electro-optical (EO) modulators are inherently built on the basis of enhancing light-matter interactions. Current EO modulators often deploy conventional materials with poor EO properties, or ring resonator structure with narrow bandwidth and thermal instability, so their dimensions and performance have nearly reached their physical limits. Future integrated photonic interconnects require EO modulators to be ultra-compact, ultra-fast, cost-effective and able to work over a broad bandwidth. The key to achieving this goal is to identify an efficient and low-cost active material. Meanwhile, novel waveguides and platforms need to be explored to significantly enhance light-active medium interaction. As widely investigated novel materials, graphene and conductive oxide (COx) have shown remarkable EO properties. The objective of this dissertation is to realize enhanced light-matter interaction based on these two novel materials and waveguiding platforms, and further develop ultra-compact, ultra-fast EO modulators for future photonic integrated circuits. The first part of this dissertation covers the theory of EO modulation mechanisms, several types of EO materials including graphene and COx, as well as fabrication techniques. The second part demonstrates greatly enhanced light absorption based on mono-/multi-layer graphene. The third part proposes the theoretical study of nanoscale EA modulators based on ENZ-slot waveguide. The fourth part explores the field effect within a MOS-like structure, and verifies the ENZ behavior of COx. The fifth part experimentally demonstrates both plasmonic and dielectric configurations for ultra-compact and ultra-fast EA modulators. The final part summarizes the work presented in this dissertation and also discusses some future work for photonic applications.

Library of Congress Subject Headings

Integrated optics--Materials; Electrooptical devices; Light absorption

Publication Date


Document Type


Student Type


Degree Name

Microsystems Engineering (Ph.D.)

Department, Program, or Center

Microsystems Engineering (KGCOE)


Stefan F Preble

Advisor/Committee Member

Bruce W Smith

Advisor/Committee Member

Karl D. Hirschman


RIT – Main Campus

Plan Codes