https://doi.org/10.1140/epjqt/s40507-023-00169-y
Research
Quantum-enhanced receiver for quadrature phase shift keying using conjugated homodyne detection
Information and Communication College, National University of Defense Technology, Wuhan, China
Received:
4
December
2022
Accepted:
18
April
2023
Published online:
2
May
2023
Coherent detection (homodyne detection/heterodyne detection) and single photon detection are commonly applied in classical communication and quantum communication/receiver respectively. In this paper, we firstly propose a quantum-enhanced receiver based on conjugated homodyne detection, which is consisted of two classical balanced homodyne detectors, for discrimination among quadrature-phase-modulated weak coherent states. Our detection part works as a photon counter in every single-shot measurement during the process of detection and feedback, which could help our quantum-enhanced receiver surpass the standard quantum limit when an optimized detection threshold τ from 0.05 to 0.3 is selected. Moreover, our proposed quantum-enhanced receiver with conjugated homodyne detectors can obtain the same low error probability as conventional quantum-enhanced receivers (with its superconducting nanowire single photon detectors’ detection efficiency 60% for pulse separation 
and 70% for 
under the same adaptive feedback countermeasures.) Meanwhile, our scheme of the quantum-enhanced receiver gains its incomparable advantages on room-temperature working condition and low cost due to the application of conjugated homodyne detectors. As far as we concerned, this is the first time to explore the performance of the quantum-enhanced receiver with commercial homodyne detectors. And the analysis in this paper may pave the way to reduce the cost of the quantum-enhanced receiver and make it more adaptable for long-distance optical communication systems.
Key words: Quantum-enhanced receiver / Conjugated homodyne detector / QPSK coherent states discrimination
© The Author(s) 2023
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