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

verfasst von
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.

Organisationseinheit(en)
Institut für Gravitationsphysik
QuantumFrontiers
Externe Organisation(en)
Max-Planck-Institut für Gravitationsphysik (Albert-Einstein-Institut)
Typ
Artikel
Journal
Physical Review Applied
Band
14
ISSN
2331-7019
Publikationsdatum
06.11.2020
Publikationsstatus
Veröffentlicht
Peer-reviewed
Ja
ASJC Scopus Sachgebiete
Physik und Astronomie (insg.)
Elektronische Version(en)
https://doi.org/10.48550/arXiv.2005.00003 (Zugang: Offen)
https://doi.org/10.1103/PhysRevApplied.14.054013 (Zugang: Offen)
https://doi.org/10.15488/10598 (Zugang: Offen)