Quantum-enhanced receiver for quadrature phase shift keying using conjugated homodyne detection

Abstract Coherent detection (homodyne detection/heterodyne detection) and single photon are commonly applied in classical communication quantum communication/receiver respectively. In this paper, we firstly propose a quantum-enhanced receiver based on conjugated homodyne detection, which is consisted of two balanced detectors, for discrimination among quadrature-phase-modulated weak coherent states. Our part works as counter every single-shot measurement during the process feedback, could help our surpass standard limit when an optimized threshold τ from 0.05 to 0.3 selected. Moreover, proposed with detectors can obtain same low error probability conventional receivers (with its superconducting nanowire detectors’ efficiency 60% pulse separation $M=8$ M = 8 70% $M=12$ 12 under adaptive feedback countermeasures.) Meanwhile, scheme gains incomparable advantages room-temperature working condition cost due application detectors. As far concerned, first time explore performance commercial And analysis paper may pave way reduce make it more adaptable long-distance optical systems.