Robust generation of orbital-angular-momentum–entangled biphotons in twisted nonlinear-waveguide arrays

Abstract

We describe the generation of photon pairs entangled in optical angular momentum through spontaneous four-wave mixing in circular arrays of nonlinear waveguides. We show that the incorporation of the array twist along the waveguides can enable robust generation even in the presence of defects and inhomogeneities. We present analytical results and numerical simulations based on coupled-mode equations for the classical pump field and a discrete Schrödinger equation for the biphoton wave function. Show more