Linear dual-comb interferometry at high power levels

Philippe Guay, Mathieu Walsh, Alex Tourigny-Plante, Jerome Genest

Research output: Contribution to journalArticlepeer-review


Detector non-linearity is an important factor limiting the maximal power and hence the signal-to-noise ratio (SNR) in dual-comb interferometry. To increase the SNR without overwhelming averaging time, photodetector non-linearity must be properly handled for high input power. Detectors exhibiting nonlinear behavior can produce linear dual-comb interferograms if the area of the detector’s impulse response does not saturate and if the overlap between successive time-varying impulse responses is properly managed. Here, a high bandwidth non-amplified balanced photodetector is characterized in terms of its impulse response to high intensity short pulses to exemplify the conditions. With a 23.5 mW average power on each detector in a balanced pair, nonlinear spectral artifacts are at least 40 dB below the spectral baseline. Absorption lines of carbon dioxide are measured to reveal lines discrepancies smaller than 0.1% with HITRAN. A spectral shape independent formulation for the dual-comb figure of merit is proposed, reaching here 7.2 × 107 Hz1/2 limited by laser relative intensity noise, but corresponding to an ideal, shot-noise limited, figure of merit for an equivalent 0.85 mW average power per comb.
Original languageEnglish (US)
Pages (from-to)4393-4404
Number of pages12
JournalOptics Express
Issue number3
StatePublished - Jan 23 2023
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2023-03-03
Acknowledged KAUST grant number(s): OSR-CRG2019-4046
Acknowledgements: Natural Sciences and Engineering Research Council of Canada; Fonds de recherche du Québec – Nature et technologies; King Abdullah University of Science and Technology (# OSR-CRG2019-4046). The authors thank David Plusquellic and Adam J. Fleisher at NIST for lending the CO2 gas cell.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics


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