Quantum Optical Integrated Sensing and Communication with Homodyne BPSK Detection

TL;DR

This paper introduces a quantum optical sensing and communication scheme using homodyne BPSK detection that jointly optimizes data transmission and phase estimation over a Gaussian channel, demonstrating a trade-off between reliability and sensing accuracy.

Contribution

It presents a novel integrated quantum sensing and communication method with an iterative algorithm for joint detection and phase estimation in a phase-insensitive Gaussian channel.

Findings

Effective joint detection and estimation demonstrated

Trade-off between communication and sensing accuracy quantified

Algorithm outperforms traditional separate approaches

Abstract

In this letter, we propose a quantum integrated sensing and communication scheme for a quantum optical link using binary phase-shift keying modulation and homodyne detection. The link operates over a phase-insensitive Gaussian channel with an unknown deterministic phase rotation, where the homodyne receiver jointly carries out symbol detection and phase estimation. We formulate a design problem that minimizes the bit-error rate subject to a Fisher information-based constraint on estimation accuracy. To solve it, we develop an iterative algorithm composed of an inner expectation-maximization loop for joint detection and estimation and an outer loop that adaptively retunes the local oscillator phase. Numerical results confirm the effectiveness of the proposed approach and demonstrate a fundamental trade-off between communication reliability and sensing accuracy.