arXiv subjects

Alex Tourigny-Plante

Publications and source records attributed to Alex Tourigny-Plante.

5 recordsLinked to original sources

arXiv2022

Linear detection of 30 mW dual-comb interferograms

Detector nonlinearity 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, specific experimental conditions must be met to ensure that photodetector nonlinearity is 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 photodetector is characterized in terms of its impulse response to high intensity short pulses to exemplify the conditions. With 30 mW of continuous power on the detector, nonlinear spectral artifacts in dual-comb interferograms are at least 35 dB below the signal. A comparative spectroscopic measurement with a frequency swept laser shows that no systematic transmittance error can be attributed to nonlinearity.

physics.optics↗

arXiv2021

Correcting photodetector nonlinearity in dual-comb interferometry

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.

physics.ins-det↗

arXiv2021

Understanding photodetector nonlinearity in dual-comb interferometry

The impact of photodetector nonlinearity on dual-comb spectrometers is described and compared to that of Michelson-based Fourier transform spectrometers (FTS). The optical sampling occurring in the dual-comb approach, being the key difference with FTS, causes optical aliasing of the nonlinear spectral artifacts. Measured linear and nonlinear interferograms are presented to validate the model. Absorption lines of H$^{13}$CN are provided to understand the impact of nonlinearity on spectroscopic measurements.

physics.optics↗

arXiv2019

Dual-comb correction with spectrally broadened fiber lasers

The phase information provided by the beat note between frequency combs and two continuous-wave lasers is used to extrapolate the phase evolution of comb modes found in a spectral region obtained via nonlinear broadening. This thereafter enables using interferogram self-correction to fully retrieve the coherence of a dual-comb beat note between two independent fiber lasers. This approach allows to forego the $f - 2f$ self-referencing of both combs, which is a significant simplification. Broadband near-infrared methane spectroscopy has been conducted as a demonstration of the simplified system's preserved performance.

physics.optics↗

arXiv2019

An open and flexible digital phase-locked loop for optical metrology

This paper presents an open and flexible digital phase lock loop optimized for laser stabilization systems. It is implemented on a cheap and easily accessible FPGA-based digital electronics platform (Red Pitaya) running a customizable open-source firmware. A PC-based software interface allows controlling the platform and optimizing the loop parameters remotely. Several tools are included to allow measurement of quantities of interest smoothly and rapidly. To demonstrate the platform's capabilities, we built a fiber noise canceler over a $400$~m fiber link. Noise cancellation was achieved over a $30$~kHz bandwidth, a value limited mainly by the delays introduced by the actuator and by the round-trip propagation over the fiber link. We measured a total latency of $565$~ns for the platform itself, limiting the theoretically achievable control bandwidth to approximately 225 kHz.

eess.SP↗