Entangled-photon pairs are an essential resource for quantum information technologies. Chip-scale sources of entangled pairs have been integrated with various photonic platforms, including silicon, nitrides, indium phosphide, and lithium niobate, but each has fundamental limitations that restrict the photon-pair brightness and quality, including weak optical nonlinearity or high waveguide loss. Here, we demonstrate a novel, ultra-low-loss AlGaAs-on-insulator platform capable of generating time-energy entangled photons in a Q>1 million microring resonator with nearly 1,000-fold improvement in brightness compared to existing sources. The waveguide-integrated source exhibits an internal generation rate greater than 20×109 pairs sec−1 mW−2, emits near 1550 nm, produces heralded single photons with >99% purity, and violates Bell's inequality by more than 40 standard deviations with visibility >97%. Combined with the high optical nonlinearity and optical gain of AlGaAs for active component integration, these are all essential features for a scalable quantum photonic platform.
@article{arxiv.2009.13462,
title = {Ultra-bright entangled-photon pair generation from an AlGaAs-on-insulator microring resonator},
author = {Trevor J. Steiner and Joshua E. Castro and Lin Chang and Quynh Dang and Weiqiang Xie and Justin Norman and John E. Bowers and Galan Moody},
journal= {arXiv preprint arXiv:2009.13462},
year = {2021}
}