Tracking Length and Differential-Wavefront-Sensing Signals from Quadrant Photodiodes in Heterodyne Interferometers with Digital Phase-Locked-Loop Readout

authored by: Gerhard Heinzel, Miguel Dovale Álvarez, Alvise Pizzella, Nils Brause, Juan José Esteban Delgado
Abstract: We propose a method to track signals from quadrant photodiodes (QPDs) in heterodyne laser interferometers that employ digital phase-locked loops for phase readout. Instead of separately tracking the four segments from the QPD and then combining the results into length and differential-wavefront-sensing signals, this method employs a set of coupled tracking loops that operate directly on the combined length and angular signals. The benefits are an increased signal-to-noise ratio in the loops and the possibility of adapting the loop bandwidths to the differing dynamical behavior of the signals being tracked, which now correspond to physically meaningful observables. We demonstrate an improvement of up to 6 dB over single-segment tracking, which makes this scheme an attractive solution for applications in precision intersatellite laser interferometry in ultralow light conditions.
Organisation(s): Institute of Gravitation Physics
QuantumFrontiers
External Organisation(s): Max Planck Institute for Gravitational Physics (Albert Einstein Institute)
Type: Article
Journal: Physical Review Applied
Volume: 14
ISSN: 2331-7019
Publication date: 06.11.2020
Publication status: Published
Peer reviewed: Yes
ASJC Scopus subject areas: Physics and Astronomy(all)
Electronic version(s): https://doi.org/10.48550/arXiv.2005.00003 (Access: Open)
https://doi.org/10.1103/PhysRevApplied.14.054013 (Access: Open)
https://doi.org/10.15488/10598 (Access: Open)

BibTeX

@article{badde958ad77423ca4fe33c0f4fa9a35,
title = "Tracking Length and Differential-Wavefront-Sensing Signals from Quadrant Photodiodes in Heterodyne Interferometers with Digital Phase-Locked-Loop Readout",
abstract = "We propose a method to track signals from quadrant photodiodes (QPDs) in heterodyne laser interferometers that employ digital phase-locked loops for phase readout. Instead of separately tracking the four segments from the QPD and then combining the results into length and differential-wavefront-sensing signals, this method employs a set of coupled tracking loops that operate directly on the combined length and angular signals. The benefits are an increased signal-to-noise ratio in the loops and the possibility of adapting the loop bandwidths to the differing dynamical behavior of the signals being tracked, which now correspond to physically meaningful observables. We demonstrate an improvement of up to 6 dB over single-segment tracking, which makes this scheme an attractive solution for applications in precision intersatellite laser interferometry in ultralow light conditions. ",
author = "Gerhard Heinzel and {\'A}lvarez, {Miguel Dovale} and Alvise Pizzella and Nils Brause and Delgado, {Juan Jos{\'e} Esteban}",
note = "Funding information: The authors acknowledge the support of the German Space Agency, DLR (Grant No. FKZ 50OQ1801); Clusters of Excellence “QuantumFrontiers: Light and Matter at the Quantum Frontier: Foundations and Applications in Metrology” (EXC-2123, Project No. 390837967), and PhoenixD: “Photonics, Optics, and Engineering–Innovation Across Disciplines” (EXC-2122, Project No. 390833453).",
year = "2020",
month = nov,
day = "6",
doi = "10.48550/arXiv.2005.00003",
language = "English",
volume = "14",
journal = "Physical Review Applied",
issn = "2331-7019",
publisher = "American Physical Society",
number = "5",
}