Compact linearly uncoupled resonators for efficient spontaneous parametric downconversion via angular phase matching

TL;DR

This paper introduces a compact integrated platform with linearly uncoupled resonators and angular phase matching for efficient second-order nonlinear interactions, achieving high photon-pair generation rates and nearly uncorrelated biphoton states.

Contribution

It presents a novel architecture that confines phase control to a small device section, enhancing nonlinear interaction while reducing size and avoiding material-specific poling.

Findings

Photon-pair generation rate of 3.16 GHz/mW in CW regime

Nearly uncorrelated photon pairs with Schmidt number K=1.02

Applicable to various integrated $$ nonlinear platforms

Abstract

We report an integrated platform for efficient second-order nonlinear interactions based on linearly uncoupled resonators and angular phase matching. The proposed architecture confines phase control to a limited section of the device, maximizing field enhancement and effective nonlinear interaction length while simultaneously reducing the overall footprint. As an example we show the results for an AlGaAs-on-insulator structure demonstrating a photon-pair generation rate of 3.16 GHz/mW in the continuous-wave regime and 5.89 MHz under pulsed pumping. The generated biphoton state exhibits a Schmidt number K=1.02, indicating nearly uncorrelated photon pairs. The compact and reconfigurable nature of this approach, together with its independence from material-specific poling techniques, makes it applicable to a broad class of integrated $\chi_2$ nonlinear platforms.