Anti-Interference High Speed Modulation Decoder for Quantum Key Distribution

Quantum key distribution is gradually moving towards network applications. It is important to improve the performance of quantum key distribution systems such as photonic integration for compact systems, the stability resistant to environmental disturbance, high key rate, and high efficiency. In this letter, we propose an orthogonal-polarizations-exchange reflector Michelson interferometer model to solve quantum channel disturbance caused by environment. Based on this model, we design a Sagnac-reflector Michelson interferometer decoder, and verify the performance of the decoder by constructing an interference system. The interference fringe visibility is greater than 98% for all four coding phases in 625MHz. The results show that the decoder can resist environmental interference and support high speed modulation frequency. In addition, the anti-interference decoder without magneto-optical device is suitable for the realization of photonic integration, which is the development trend of the next generation quantum communication devices.