Linear dual-comb interferometry at high power levels

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

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

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
Volume31
Issue number3
DOIs
StatePublished - Jan 23 2023
Externally publishedYes

ASJC Scopus subject areas

  • Atomic and Molecular Physics, and Optics

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