Phase tracking for sub-shot-noise-limited receivers

Phase trackingNonconventional receivers for phase-coherent states based on non-Gaussian measurements such as photon counting surpass the sensitivity limits of shot-noise-limited coherent receivers, the quantum noise limit (QNL). These non-Gaussian receivers can have a significant impact in future coherent communication technologies.

However, random phase changes in realistic communication channels, such as optical fibers, present serious challenges for extracting the information encoded in coherent states.

While there are methods for correcting random phase noise with conventional heterodyne detection, phase tracking for non-Gaussian receivers surpassing the QNL is still an open problem.

Here we demonstrate phase tracking for non-Gaussian receivers to correct for time-varying phase noise while allowing for decoding beyond the QNL.
The phase-tracking method performs real-time parameter estimation and correction of phase drifts using the data from the non-Gaussian discrimination measurement, without relying on phase reference pilot fields.

This method enables non-Gaussian receivers to achieve higher sensitivities and rates of information transfer than ideal coherent receivers in realistic channels with time-varying phase noise.

This demonstration makes sub-QNL receivers a more robust, feasible, and practical quantum technology for classical and quantum communications.

See the article

Posted in Becerra Group News, CQuIC publications.
Francisco Elohim Becerra

About the Author:

Dr. Francisco Elohim Becerra received his M.S. in 2005 and his Ph.D. in 2009 in Physics at the Centro de Investigaciones y Estudios Avanzados, Mexico. He performed his Ph.D. research at the Joint Quantum Institute (JQI) at the University of Maryland in the area of quantum optics with atomic ensembles. He was a postdoctoral researcher at the National Institute of Standards and Technology (NIST), Gaithersburg, MD, from 2010 to 2013 performing research in quantum measurements and nonconventional detection methods. In 2013, he joined the Department of Physics and Astronomy at the University of New Mexico (UNM) as an Assistant Professor. His current research involves quantum measurements of light for efficient communications, and quantum optics and atom-photon interfaces for long distance quantum communication.