Four-state quantum encoder and decoder for phase modulation polarization encoding and quantum key distribution system

Abstract

The invention discloses a four-state quantum encoder and decoder for phase modulation polarization encoding and a quantum key distribution system. The encoder and the decoder have intrinsic stability, namely, the working stability is not influenced by the external environment or connecting optical fibers which can be common mono-mode optical fibers. The quantum encoder and decoder can be applied to the field of quantum key distribution, the whole system comprises a transmitting end and a receiving end, and the transmitting end and the receiving end are connected through a quantum channel to complete the key distribution process. The quantum encoder and decoder can achieve BB84 protocol four-state quantum key encoding and decoding with intrinsic stability. The common mono-mode optical fibers can be used as all the connecting optical fibers without using polarization-maintaining optical fibers, and interference with the phase drift and polarization change of the system from the external environment has no influence on the encoding or decoding process at all.

Description

technical field

[0001] The invention relates to the field of quantum communication, in particular to an inherently stable phase modulation polarization coding four-state quantum encoder and decoder and a quantum key distribution system. Background technique

[0002] In quantum secure communication technology, the most commonly used encoding methods are phase encoding and polarization encoding. In the past, polarization encoding usually uses two linear polarization states of photons to encode, that is, electro-optic crystals or Pockels cells are used to encode the linear polarization states of photons, but the half-wave voltage of electro-optic crystals or Pockels cells is very high (several thousand volts). , it is very inconvenient to use, and it is difficult to achieve high-speed encoding. However, if two mutually perpendicular linearly polarized lights are used to synthesize, the final polarized light is determined by the phase difference between the two mutually perpend...

Images