Enhanced Nonlinear Frequency Conversion Bandwidth through Birefringence induced Mode Hybridization

TL;DR

This paper presents a broadband nonlinear frequency conversion technique using mode hybridization in lithium niobate micro-resonators, enabling efficient quantum information transfer and multiplexing on integrated photonic chips.

Contribution

It introduces a novel mode-hybridization approach in thin film lithium niobate for broadband second harmonic generation with simultaneous quasi-phase and group velocity matching.

Findings

Achieved 13 nm 3-dB bandwidth in SHG

Demonstrated broadband frequency conversion for ultra-short pulses

Enabled potential for on-chip quantum light sources

Abstract

On-chip quantum information network requires qubit transfer between different wavelengths while preserving quantum coherence and entanglement, which needs broadband up-conversion available. Herein, we demonstrate a mode-hybridization based broadband nonlinear frequency conversion on X-cut thin film lithium niobate. With the spontaneous quasi-phase matching and quasi groupvelocity matching being simultaneously satisfied, broadband second harmonic generation with a 3-dB bandwidth up to 13 nm has been achieved in a micro-racetrack resonator. The same mechanism can work on the frequency conversion of the ultra-short pulse in the bent waveguide structure. This work will be beneficial to on-chip tunable frequency conversion and quantum light source generation on integrated photonic platforms, and further enable on-chip large-capacity multiplexing, multichannel optical information processing, and large quantum information networks.