Correcting photodetector nonlinearity in dual-comb interferometry

TL;DR

This paper presents an iterative algorithm to correct photodetector nonlinearity in dual-comb spectroscopy, significantly improving signal-to-noise ratio and measurement accuracy by reducing spectral artifacts and saturation errors.

Contribution

It introduces a novel iterative correction method adapted from classical spectrometry techniques to address nonlinearity in dual-comb detection systems.

Findings

Enhanced signal-to-noise ratio in dual-comb measurements.

Effective correction of detector saturation effects.

Validation with H$^{12}$CN lines showing residuals limited by noise.

Abstract

Photodetector nonlinearity, the main limiting factor in terms of optical power in the detection chain, is corrected to improve the signal-to-noise ratio of a short-time measurement in dual-comb spectroscopy. An iterative correction algorithm minimizing out-of-band spectral artifacts based on nonlinearity correction methods used in classical Fourier-transform spectrometers is presented. The exactitude of the nonlinearity correction is validated using a low power linear measurement. Spectroscopic lines of H$^{12}$CN are provided and the error caused by the saturation of the detector is corrected yielding residuals limited by the measurement noise.