Thin Photonic Power Converters Designs with Back Reflector Operating at a 1310 nm Wavelength

Abstract

We designed and simulated thin yet highly efficient single-junction monochromatic photonic power converters (PPCs) operating at 1310 nm. The PPCs are composed of absorber layers of InAlGaAs lattice-matched to InP. To enhance light absorption within a thin device, we employed an inverted design suitable for substrate removal and integration of a metallic back reflector (BR). Two BR designs are proposed with flat (FBR) and textured (TBR) surfaces, and the structures are optimized to support absorption resonances at 1310 nm. Fabry-Perot and guided mode resonances lead to strong, near complete absorption at the target wavelength without antireflection coating. Opto-electrical simulations demonstrated that 6 and 12 times thinner absorbing layers for FBR and TBR structures, respectively, can preserve short-circuit current density ( $J_{\text{sc}}$ ) and fill factor (FF), and improve open-circuit voltage ( $V_{\text{oc}}$ ) and power conversion efficiency (PCE) relative to conventional designs. A simulated PCE of 48% was obtained under normal-incidence laser illumination at 1310 nm for these thin devices. These lightweight and efficient PPCs are suitable for power over fiber and free-space power beaming applications.