Narrowband and high-rate entangled photon-pair generation from a high-Q silicon microring resonator

TL;DR

This paper reports the development of a high-Q silicon microring resonator that efficiently generates entangled photon pairs with narrow bandwidth and high rate, suitable for quantum communication applications.

Contribution

The study demonstrates optimized silicon microring resonators with suppressed sidewall scattering achieving an intrinsic Q-factor of 1.26 million and high photon-pair generation rates in CMOS-compatible fabrication.

Findings

Achieved an intrinsic Q-factor of 1.26×10^6.

Generated photon pairs at a rate of 9.19 MHz.

Confirmed high-quality entanglement with 98% visibility.

Abstract

Entangled photon-pair sources are indispensable building blocks of quantum information processing technologies. Among the available approaches, on-chip microresonators are particularly promising owing to their resonant enhancement, CMOS-compatible fabrication, and wafer-scale integration capabilities. In this study, we optimized the structure of silicon microring resonators to suppress sidewall scattering. As a result, we achieved an intrinsic Q-factor of 1.26$\times$10$^6$ using only standard fabrication processes. The high-Q resonator enabled a brightness coefficient of 3.9$\times$10$^9$ Hz/GHz/mW$^2$, with a maximum brightness of 22.0 MHz/GHz and a maximum photon-pair generation rate of 9.19 MHz. Furthermore, Franson-type two-photon interference exhibited a visibility of 98.0$\pm$0.2%, confirming time-energy entanglement. These results show that narrow bandwidth and high generation rate can be achieved simultaneously in CMOS-compatible silicon photonic sources, advancing their use in quantum repeaters.