Electro-optic frequency comb-empowered precise measurement of the dynamic frequency of a laser

TL;DR

This paper introduces a novel integrated lithium niobate electro-optic frequency comb technique that enables ultra-precise, high-speed tracking of frequency-modulated lasers, significantly advancing applications in spectroscopy, LiDAR, and fundamental measurements.

Contribution

The work demonstrates a new integrated electro-optic frequency comb with wide tunability and high bandwidth, achieving unprecedented frequency tracking speed for frequency-modulated lasers.

Findings

Achieved frequency tracking with a chirp rate of 2×10^18 Hz/s.

Enabled precise measurement of laser frequency with severe mode hops.

Potential to improve ranging resolution and acquisition rate.

Abstract

Frequency-modulated lasers (FMLs) are widely used in spectroscopy, biology, and LiDAR. The performance of these applications highly depends on the fast and precise tracking of the FMLs' absolute frequency, which remains a challenge. Here we demonstrate integrated lithium niobate electro-optic frequency combs with arbitrarily tunable repetition rates and a 29.45-nm bandwidth, enabling precise tracking of the absolute frequency of an FML with a chirp rate as high as $2\times10^{18}\,\mathrm{Hz/s}$, which is over three orders of magnitude above the state of the art. This method enables frequency-modulated continuous-wave ranging using an FML with severe mode hops, unlocking great potential for improving the ranging resolution and acquisition rate. Our method lays the foundation for FML-based high-precision measurements of frequency, distance, and time, leading to profound implications in fundamental science and engineering applications.