# Ultra-low loss integrated visible photonics using thin-film lithium niobate

## TL;DR

This paper presents an ultra-low loss integrated visible photonics platform using thin-film lithium niobate, enabling high-quality resonators and high-speed modulators for applications in quantum science and optical technologies.

## Contribution

The work introduces a novel integrated visible photonics platform with record-low propagation loss and high-Q resonators based on thin-film lithium niobate, expanding capabilities in the visible spectrum.

## Key findings

- Propagation loss of 6 dB/m at 637 nm
- Intrinsic quality factor of 11 million for microring resonators
- Electro-optic bandwidth of 10 GHz for on-chip modulators

## Abstract

Integrated photonics is a powerful platform that can improve the performance and stability of optical systems, while providing low-cost, small-footprint and scalable alternatives to implementations based on free-space optics. While great progress has been made on the development of low-loss integrated photonics platforms at telecom wavelengths, visible wavelength range has received less attention. Yet, many applications utilize visible or near-visible light, including those in optical imaging, optogenetics, and quantum science and technology. Here we demonstrate an ultra-low loss integrated visible photonics platform based on thin film lithium niobate on insulator. Our waveguides feature ultra-low propagation loss of 6 dB/m, while our microring resonators have an intrinsic quality factor of 11 million, both measured at 637 nm wavelength. Additionally, we demonstrate an on-chip visible intensity modulator with an electro-optic bandwidth of 10 GHz, limited by the detector used. The ultra-low loss devices demonstrated in this work, together with the strong second- and third-order nonlinearities in lithium niobate, open up new opportunities for creating novel passive, and active devices for frequency metrology and quantum information processing in the visible spectrum range.