# Self-corrected chip-based dual-comb spectrometer

## TL;DR

This paper introduces a compact, chip-based dual-comb spectrometer with a novel self-correction algorithm that simplifies operation and achieves high-resolution molecular spectra without external references.

## Contribution

The work presents the first integration of two passively mode-locked waveguide lasers on a single chip with a self-correction method for stable dual-comb spectroscopy.

## Key findings

- Achieved high mutual stability of free-running frequency combs.
- Developed a self-correction algorithm using ambiguity functions.
- Demonstrated high-resolution molecular spectrum over 20 nm.

## Abstract

We present a dual-comb spectrometer based on two passively mode-locked waveguide lasers integrated in a single Er-doped ZBLAN chip. This original design yields two free-running frequency combs having a high level of mutual stability. We developed in parallel a self-correction algorithm that compensates residual relative fluctuations and yields mode-resolved spectra without the help of any reference laser or control system. Fluctuations are extracted directly from the interferograms using the concept of ambiguity function, which leads to a significant simplification of the instrument that will greatly ease its widespread adoption. Comparison with a correction algorithm relying on a single-frequency laser indicates discrepancies of only 50 attoseconds on optical timings. The capacities of this instrument are finally demonstrated with the acquisition of a high-resolution molecular spectrum covering 20 nm. This new chip-based multi-laser platform is ideal for the development of high-repetition-rate, compact and fieldable comb spectrometers in the near- and mid-infrared.