Capacitance-Free Integrated Circuit Interconnects

A compact high speed logic gate is proposed that will switch with a speed under 10 psecs with a power-time product of less than 7 fJ. The electrical power should be less than 1 mA at 1.5 Volts. Unlike all-electronic logic, this opto-electronic logic gate's speed and power will remain fast and low, even when incorporated in large integrated optical circuits with thousands of external connections. Very Large Scale Integrated Optics (VLSIO), capable of over 50,000 high speed logic gates per square centimeter, has been created from a new class of Ultra High Confinement (UHC) waveguides to work with this logic gate. This Phase I proposes to create an electronic logic function with an infrared integrated optical input. The infrared signal output will be through a previously developed modulator, to be integrated post Phase I. The Phase I logic device will consist of a room temperature intersubband photodetector at 10 micrometer wavelengths for input coupled to a resonant tunneling diode for logic function. The device is created with a Ge waveguide on GaAs quantum wells. This waveguide device will be evaluated for speed, power, voltage, logic function, and integration with the modulator developed previously.