# Coherent two-octave-spanning supercontinuum generation in lithium-niobate waveguides

## TL;DR

This paper reports the generation of a coherent supercontinuum spanning over two octaves in lithium-niobate waveguides, enabling direct detection of the carrier-envelope offset frequency with high signal-to-noise ratio.

## Contribution

It demonstrates for the first time a monolithic lithium-niobate waveguide producing a two-octave supercontinuum with integrated dispersion engineering for fCEO detection.

## Key findings

- Achieved over two octaves of bandwidth in a 0.5-cm waveguide.
- Enabled direct fCEO detection with 30-dB SNR.
- Utilized second- and third-order nonlinear effects for supercontinuum generation.

## Abstract

We demonstrate coherent supercontinuum generation (SCG) in a monolithically integrated lithium-niobate waveguide, under the presence of second- and third-order nonlinear effects. We achieve more than two octaves of optical bandwidth in a 0.5-cm-long waveguide with 100-picojoule-level pulses. Dispersion engineering of the waveguide allows for spectral overlap between the SCG and the second harmonic which enables direct detection of the carrier-envelope offset frequency fCEO using a single waveguide. We measure the fCEO of our femtosecond pump source with a 30-dB signal-to-noise ratio.