Realization of Ultrathin GaAs Photonic Power Converters with Rear-Side Metal Grating on Full 4” Wafers

Photonic power converters (PPCs) attract more and more attention as they enable galvanically isolated optical power transmission. In many power by light applications, conversion efficiency is the key metric for PPCs. A remarkable efficiency of 68.9% was recently achieved by utilizing Fabry-Perot resonances in a GaAs PPC. In this work, we extend this idea of leveraging optical resonance towards strong grating coupled guided mode resonances. A proof of concept is demonstrated by ultrathin GaAs PPCs with an absorber thickness of 160 nm with nanostructured photonic reflectors. Reference ultrathin devices on substrate and with planar mirror show close-to-bandgap EQE of 13% and 20%, respectively, while guided modes resonances yield an EQE of 45% at 840 nm for devices with photonic mirror. Devices were realized on full 4-inch wafers, using processes compatible with industrial manufacturing.