Toward 1% single-photon anharmonicity with periodically poled lithium niobate microring resonators

Juanjuan Lu,Chang-Ling Zou,Ming Li,Hong X Tang,Ayed Al Sayem

doi:10.1364/optica.403931

Abstract

The absence of the single-photon nonlinearity has been a major roadblock in developing quantum photonic circuits at optical frequencies. In this paper, we demonstrate a periodically poled thin film lithium niobate microring resonator (PPLNMR) that reaches 5,000,000%/W second-harmonic conversion efficiency—almost 20-fold enhancement over the state-of-the-art—by accessing its largest χ ( 2 ) tensor component d 33 via quasi-phase matching. The corresponding single-photon coupling rate g / 2 π is estimated to be 1.2 MHz, which is an important milestone as it approaches the dissipation rate κ / 2 π of best-available lithium niobate microresonators developed in the community. Using a figure of merit defined as g / κ , our device reaches a single-photon nonlinear anharmonicity approaching 1%. We show that, by further scaling of the device, it is possible to improve the single-photon anharmonicity to a regime where photon blockade effect can be manifested.

Highlights

Quantum photonic integrated circuits have received growing interests since such platforms offer the stability and integrability towards solid state quantum applications [1–6]
We describe a 20-fold enhancement over state-of-the-art devices in second harmonic generation (SHG) [23, 24] with the thin film periodically poled lithium niobate microring resonators (PPLNMRs) by leveraging its largest χ(2) tensor element d33 for quasi-phase matching
This exceptionally high nonlinearity translates to a vacuum photonphoton coupling strength g/2π of 1.2 MHz, which is an important milestone as it approaches the dissipation rate κ of best available Lithium niobate (LN) microresonators [25]

Summary

INTRODUCTION

Quantum photonic integrated circuits have received growing interests since such platforms offer the stability and integrability towards solid state quantum applications [1–6]. We describe a 20-fold enhancement over state-of-the-art devices in second harmonic generation (SHG) [23, 24] with the thin film periodically poled lithium niobate microring resonators (PPLNMRs) by leveraging its largest χ(2) tensor element d33 for quasi-phase matching. This exceptionally high nonlinearity translates to a vacuum photonphoton coupling strength g/2π of 1.2 MHz, which is an important milestone as it approaches the dissipation rate κ of best available LN microresonators [25]. The FOM indicates the number of quantum gate operations on single photons before significant fidelity loss due to the photon dissipation to environment

OPTIMIZATION OF COUPLING STRENGTH g

CHARACTERIZATION OF g

DISCUSSION AND OUTLOOK

CONCLUSION