arXiv:2002.09275 · Frontiers in Optics

Programming the Kennedy Receiver for Capacity Maximization versus Minimizing One-shot Error Probability

Rahul Kumar Bhadani, Michael R. Grace, Ivan B. Djordjević, Jonathan M. Sprinkle, Saikat Guha

Published Jan 1, 2020• 1 citation

Abstract

We find the capacity attained by the Kennedy receiver for coherent-state BPSK when the symbol prior p and pre-detection displacement β are optimized. The optimal β is different than what minimizes error probability for single-shot BPSK state discrimination.

DOI: 10.1364/fio.2020.jm6b.29

Related papers

Atmospheric Turbulence-Aware Optimization of Generalized Kennedy Receivers for Coherent-State BPSK Quantum Communication

Md Ashraf Hossain Ifty, Rahul Bhadani

We investigate generalized Kennedy receivers for coherent-state BPSK communication over turbulent free-space optical channels. An ergodic mutual-information framework is developed to jointly optimize the receiver displacement and input prior probabilities under Gamma--Gamma fading.

quant-pharXiv:2609.05471Aug 24, 20260 citations

Optimized Squeezing Operation for Phase-Shift Keying Quantum State Discrimination

Rahul Kumar Bhadani, Ivan B. Djordjević

Many receiver designs have been studied in the past to discriminate Phase-Shift Keying (PSK) quantum states that are used to encode information before transmitting over the communication channel. Among many types of quantum states, there has been significant work on the use of coherent states for encoding information. Previous work has sought to improve the communication performance in terms of various metrics such as error probability of state discrimination and capacities by employing more complex quantum states such as squeezed-displaced states. One of the simplest receivers for state discrimination is the displacement receiver. However, our calculation demonstrates that when we use optimal parameters for a displacement receiver, squeezed-displaced states might not be necessary, and merely using coherent states suffice. We see no performance improvement in terms of probability of error of state discrimination as well as mutual information using displacement receivers when optimal squeezing parameters are used with squeezing operation on the transmitter side for BPSK and QPSK. In addition, we also study the receiver design scheme for QPSK modulation where squeezing is employed at the receiver side. We find that using squeezing operation on the receiver side just before detection provides an advantage in terms of increased mutual information for the low-photon regime compared to when no squeezing is used. For all other cases, squeezing offers no additional advantage.

IEEE AccessJan 1, 20221 citation

Constellation Optimization for Phase-Shift Keying Coherent States With Displacement Receiver to Maximize Mutual Information

Rahul Kumar Bhadani, Ivan B. Djordjević

An important problem in quantum information theory is finding the best possible capacity of the optical communication channel employing suitable codewords, receiver design, and constellation optimization techniques. In this paper, we derive an alternative channel capacity, CG, of phase-shift keying coherent state with a realizable displacement receiver by maximizing mutual information over symbol priors and pre-detection displacement. We find that CGis higher than the capacity achieved by maximizing mutual information over symbol prior but with zero displacement. The overall scheme demonstrates designing an improved, yet easy-to-implement receiver for better communication performance by tuning it at different photon number regime. Further, we present a comparative analysis of CGwith existing receiver designs. We extend our study to account for detector imperfections.imperfections.

IEEE AccessJan 1, 20207 citations

Demonstration of Near-Optimal Discrimination of Optical Coherent States

Christoffer Wittmann, Masahiro Takeoka, K. N. Cassemiro +3 more

The optimal discrimination of nonorthogonal quantum states with minimum error probability is a fundamental task in quantum measurement theory as well as an important primitive in optical communication. In this work, we propose and experimentally realize a new and simple quantum measurement strategy capable of discriminating two coherent states with smaller error probabilities than can be obtained using the standard measurement devices: the Kennedy receiver and the homodyne receiver.

arXiv:0809.4953Physical Review LettersNov 17, 2008123 citations

Optimal receiver for coherent signals

Сыч Денис Васильевич, Gerd Leuchs

We propose a practical receiver scheme for discriminating coherent signals with the error rate unconditionally below the standard quantum limit (or shot noise). For BPSK signals the error rate goes down to the Helstrom bound.

Conference on Lasers and Electro-OpticsJan 1, 20160 citations

Cut-off rate analysis of practical quantum receivers

Masahiro Takeoka, Kenji Tsujino, Masahide Sasaki

Quantum communication with binary nonorthogonal pure states and single-shot measurements are discussed in terms of reliability function and cut-off rate. It is shown that some of different measurement strategies simultaneously attain the maximum single-shot cut-off rate. We also apply these measurements to the BPSK optical coherent states and compare them with the homodyne detection. Numerical results show that even including realistic imperfections, it is possible to exceed the homodyne limited cut-off rate.

Journal of Modern OpticsAug 25, 20099 citations