Ultracompact, High-Speed Field-Effect Optical Modulators(Research Topic 4.2 Optoelectronics)
Abstract
The objective of this project is to develop ultracompact, high-speed, broad band field-effect optical modulators (FEOMs) based on conductive oxide as the active material. Two electro-absorption (EA) modulators are proposed: (1) nanoscale (<1µm), high-speed (>10Gb/s) EA plasmonic modulator; (2) wavelength-scale (1~2µm), high-speed (>10Gb/s) dielectric EA optical modulator based on the silicon-on-insulator (SOI) platform. Field effect in metal-oxide-semiconductor (MOS) capacitors plays a key role in field-effect transistors (FETs), the fundamental building blocks of modern digital integrated circuits. Recent works show that the field effect can also be used to make optical/plasmonic modulators. To enhance the impact of the field effect on light propagation, conductive oxide (COx) is introduced as the active material in a metal-insulator-COx (MIC) structure, where the optical properties of COx can be significantly altered by modulating-electric-field- induced charge. According to the bias polarity and strength, an MIC structure may work in two well-known modes, namely ÒdepletionÓ and ÒaccumulationÓ, which result in low attenuation (ON state) and high attenuation (OFF state), respectively, when the MIC structure is integrated in an optical or plasmonic waveguide. More recently, we demonstrated a field-effect EA plasmonic modulator with waveguide length only 800 nm, the smallest recorded dimension according to our knowledge. Preliminary results show that it has extinction ratio of 1.75 (2.43 dB) at 10 MHz and can potentially operate at high speed. The results reveal great opportunities for the development of a new generation of optical modulators based on the field effect. The effort of this project will be focused on the following tasks: (a) Application of the optimal fabrication of COx and novel high-k insulators in optical modulators (1-6 months). (b) Demonstration of high-speed and larger extinction ratio operation of the EA plasmonic modulator (7-12 months). (c) Application of the EA modulation technique in the SOI platform to develop silicon EA modulators (13-24 months). (d) Demonstration of ultracompact, high-speed silicon EA optical modulators (25-36 months). Success of the project will result in low-cost, CMOS-compatible, high-speed, broadband EA plasmonic modulator and dielectric EA optical modulator as small as transistors. The modulators to be developed may play key roles in future chip-to-chip (including 3D vertical chip-to-chip) optical interconnection, and on-chip nanoscale optical interconnection. Similar as their counterparts, FETs, these FEOMs may eventually become fundamental building blocks for photonic integration.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Dec 04, 2018
- Source ID
- W911NF1610357
Entities
People
- Karl Hirschman
Organizations
- Army Contracting Command
- Rochester Institute of Technology
- United States Army