Optical Communication and Energy Conversion for Small-Footprint Edge Computing

Abstract

Advancement in microelectronics technology enables autonomous edge computing platforms in the size of a dust mote, bringing efficient and low cost artificial intelligence computing close to end users. The key components of these edge computers include (i) communication devices to talk to nearby host computers and (ii) power sources to convert energy to on-chip electrical power. As RF communication and power converters suffer from low efficiency with reduced antenna size, optical devices can provide much higher efficiency in sub-centimeter footprint. As there is limited energy storage inside the small footprint of edge computers, we developed power-saving light-emitting-diodes (LEDs) with high efficiency at ultra-low current and voltage, by improving the quantum well interface quality and increase the radiative radiation rate at low injection current. The device exhibits close to unity internal quantum efficiency at a current density orders of magnitude lower than conventional LEDs. Wireless communication is demonstrated at these conditions. We also investigated dust-sized III-V photovoltaic (PV) cells grown on Si and Silicon-on-insulator substrate, considering surface passivation and crystallographic defects. We demonstrated high power density micro-PVs on Si substrate that can be heterogeneously integrated using wafer-level-packaging with other chiplets. (i) N. Li et al. Nat. Photonics 13, 588–592 (ii) N. Li et al. Advanced Mat. to be published