Anti-Interference High-Speed Modulation Decoder for Quantum Key Distribution

Quantum key distribution is increasingly transitioning toward network applications, necessitating advancements in system performance, including photonic integration for compact designs, enhanced stability against environmental disturbances, higher key rates, and improved efficiency. In this letter, we propose an orthogonal polarization exchange reflector Michelson interferometer model to address quantum channel disturbances caused by environmental factors. Based on this model, we designed a Sagnac reflector-Michelson interferometer decoder and verified its performance through an interference system. The interference fringe visibility exceeded 98% across all four coding phases at 625 MHz. These results indicate that the decoder effectively mitigates environmental interference while supporting high-speed modulation frequencies. In addition, the proposed anti-interference decoder, which does not rely on magneto-optical devices, is well-suited for photonic integration, aligning with the development trajectory for next-generation quantum communication devices.