Abstract
Quantum networking continues to encode information in polarization states due to ease and precision. The variable environmental polarization transformations induced by deployed fiber need correction for deployed quantum networking. Here, we present a method for automatic polarization compensation (APC) and demonstrate its performance on a metropolitan quantum network. Designing an APC involves many design decisions as indicated by the diversity of previous solutions in the literature. Our design leverages heterodyne detection of wavelength-multiplexed dim classical references for continuous high-bandwidth polarization measurements used by newly developed multi-axis (non-)linear control algorithm(s) for complete polarization channel stabilization with no downtime. This enables continuous relatively high-bandwidth correction without significant added noise from classical reference signals. We demonstrate the performance of our APC using a variety of classical and quantum characterizations. Finally, we use C-band and L-band APC versions to demonstrate continuous high-fidelity entanglement distribution on a metropolitan quantum network with an average relative fidelity of 0.94 ± 0.03 for over 30 hrs.
| Original language | English |
|---|---|
| Pages (from-to) | 47589-47619 |
| Number of pages | 31 |
| Journal | Optics Express |
| Volume | 32 |
| Issue number | 26 |
| DOIs | |
| State | Published - Dec 16 2024 |
Funding
U.S. Department of Energy (DE-AC05-00OR22725); Oak Ridge National Laboratory (Laboratory Directed Research and Development); Advanced Scientific Computing Research (ERKJ432); University of Tennessee at Chattanooga (Quantum Initiative). J. C. C. led the project and demonstration design, as well as devised, constructed, and tested the APC, and also led the results, analysis, and paper composition. M. A. developed the entanglement source, tomography systems, and upgraded time-tagger hardware, as well as helping with results, analysis, and paper composition. K. R. provided experimental assistance during the Chattanooga testing and demonstration. T. L. facilitated laboratory usage for the Chattanooga testing and demonstration and assisted with paper composition. M. K. provided helpful managerial oversight and assisted with paper composition. Most of this work was performed at Oak Ridge National Laboratory, operated by UT-Battelle for the U.S. Department of Energy under contract no. DE-AC05-00OR22725. J.C. and M. A. acknowledge research sponsored by the Laboratory Directed Research and Development Program of Oak Ridge National Laboratory, managed by UT-Battelle, LLC, for the U. S. Department of Energy. J.C. acknowledge the polarization characterization hardware development sponsored by U.S. Department of Energy, Office of Science, Advanced Scientific Computing Research, under the Performance integrated quantum scalable internet program (Field Work Proposal ERKJ432). T.L. and K.R. acknowledge the support of the UTC Quantum Initiative in contributing to this work.