On-chip $\chi^{(2)}$ microring optical parametric oscillator

TL;DR

This paper demonstrates a low-threshold, tunable on-chip optical parametric oscillator using aluminum nitride microring resonators, achieving high efficiency and broad bandwidth for potential quantum and sensing applications.

Contribution

It introduces a highly efficient, low-threshold, chip-integrated $ ext{chi}^{(2)}$ microring OPO with broad tunability and high output, advancing integrated nonlinear optics.

Findings

Achieved milliwatt-level output power with 17% efficiency.

Demonstrated broadband tunability over 180 nm in the C band.

Enabled low-threshold parametric oscillation in integrated photonics.

Abstract

Optical parametric oscillators (OPOs) have been widely used for decades as tunable, narrow linewidth, and coherent light sources for reaching long wavelengths and are attractive for applications such as quantum random number generation and Ising machines. To date, waveguide-based OPOs have suffered from relatively high thresholds on the order of hundreds of milliwatts. With the advance in integrated photonic techniques demonstrated by high-efficiency second harmonic generation in aluminum nitride (AlN) photonic microring resonators, highly compact and nanophotonic implementation of parametric oscillation is feasible. Here, we employ phase-matched AlN microring resonators to demonstrate low-threshold parametric oscillation in the telecom infrared band with an on-chip efficiency up to 17% and milliwatt-level output power. A broad phase-matching window is observed, enabling tunable generation of signal and idler pairs over a 180 nm bandwidth across the C band. This result establishes an important milestone in integrated nonlinear optics and paves the way towards chip-based quantum light sources and tunable, coherent radiation for spectroscopy and chemical sensing.