Investigation of practical application for QAM hybrid receiver

TL;DR

This paper introduces a hybrid quantum receiver for 16-QAM states that combines homodyne detection and displacement measurement, outperforming the standard quantum limit and showing promise for practical quantum communication applications.

Contribution

The paper proposes a novel hybrid receiver design for QAM states that improves discrimination performance over existing methods using a two-step measurement process.

Findings

Outperforms the standard quantum limit for 16-QAM

Reduces the need for many codeword partitions

Uses on-off detectors effectively

Abstract

We present a quantum receiver for quadrature amplitude modulation (QAM) coherent states discrimination with homodyne-displacement hybrid structure. Our strategy is to carry out two successive measurements on parts of the quantum states. The homodyne result of the first measurement reveals partial information about the state and is forward to a displacement receiver, which finally identifies the input state by using feedback to adjust a reference field. Numerical simulation results show that for 16-QAM, the hybrid receiver could outperform the standard quantum limit (SQL) with a reduced number of codeword interval partitions and on-off detectors, which shows great potential toward implementing the practical application.