Year: 2026
Type: preprint
Abstract: Hadamard-coded optical receivers typically rely on stable interference conditions, which can motivate active optical phase control. We investigate a fixed, intensity-only decoder that embeds four populated modes in an eight-mode interferometer and provides six complementary trigonometric observables through simultaneous power measurements. An analytic transition decoder uses the resulting sign-change patterns without continuous optical phase stabilization. The receiver's intensity-to-observable map is inverted exactly, and an identifiability analysis characterizes exceptional phase configurations and conditional noise sensitivity. An ideal, equal-photon-budget comparison with conventional four-port Hadamard decoding illustrates the potential value of the additional outputs without implying an unconditional advantage. Measurements on programmable photonic processors give 96.19% accuracy for the analytical decoding experiment; a complementary machine-learning analysis reports 98.31% on a held-out experimental trace. These results demonstrate an intensity-only, phase-aware approach to differential Hadamard decoding under the tested conditions, while larger codebooks and hardware-level energy benefits remain topics for future investigation.
Source: arXiv (Cornell University)
Authors: Elmas, Gökhan, Litvin, Igor A, Nötzel, Janis
Institution: Technical University of Munich
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1062995055, Verbundprojekt: Quantenkommunikation für Internet-of-Things-Netzwerke - QUIET -, G177143538, Verbundprojekt: Quanten Drahtloses Campusnetzwerk - QD-CamNetz - , Teilvorhaben: TP-Boche: Quantenklassische Verbindungen, TP-Deppe: Quantenklassischen Verbindungsschicht Protokolle, TP-Nötzel: Quantenklassiche Simulations/Emulations-Plattform, Verbundprojekt: Digitale Transformation und Souveränität künftiger Kommunikationsnetze - 6G-life -, Teilvorhaben: Grundlagen und Systemlösungen für Post Shannon Kommunikation, In-Network Computing, eingebettete Sicherheit und Resilienz, G3690431148, G5519890835, Verbundprojekt: Quantum Physical Layer Service Integration - QuaPhySI -, Teilvorhaben: Netzkonzepte und Theoretische Grundlagen, G6984449769, G7472567491, Verbundprojekt: Quantum Secure Transmission, Authentication, Resilience & Sensing - Q-STARS -
OpenAlex ID: W7223206171