Sending end for realizing encoding of six polarization states, encoding method and quantum communication system

Abstract

The invention discloses a sending end for realizing encoding of six polarization states, a coding method and a quantum communication system. The present invention relates to the sending terminal for the quantum communication system, an encoding method, and the quantum communication system, which enable encoding of four polarization states, such as H and V, commonly used in the preparation of a BB84 protocol to be achieved with a minimum number of optical elements and in a most stable manner, and also enable encoding of two other polarization states, such as H and V, to be prepared.

Description

technical field [0001] The invention relates to the field of quantum secure communication, in particular to a sending end, an encoding method and a quantum communication system for realizing encoding of six polarization states. Background technique [0002] Quantum key distribution technology can generate completely consistent and unconditionally secure keys between the two parties in communication, so it has received widespread attention. Since the proposal of the BB84 scheme in 1984, various theoretical schemes have been perfected day by day, and the technical realization has gradually matured and moved towards practical application. In quantum communication systems, encoding qubits using the polarization information of quantum states is one of the most mainstream schemes. In polarization-encoded quantum communication, it is usually necessary to transmit four quantum states with different polarizations, and there are mainly two ways to realize them. One is a multi-laser ...

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Problems solved by technology

[0006] However, two 4-state encoders are required in this six-state quantum encoder, and multiple modulation devices are required. The optical path is relatively complicated, and the overall cost is greatly increased due to the complexity of the device.

On the other hand, in this encoder, a single-mode fiber is used to connect the two interferometers, so a polarization controller ( figure 1 10) in the code to accurately control the polarization state, which greatly reduces the stability of the system and is easily affected by environmental temperature changes or vibrations

In addition, due to the use of multiple devices in the encoder, the system size is difficult to reduce and the integration level is poor

[0007] CN 201811496007.1 patent application discloses a quantum secure communication optical path, but it is used to realize the preparation of six quantum states in the time phase state, and the optical path also has a complex structure, requires multiple modulation devices, and the system volume is difficult reduction, poor integration, etc., and cannot be used to prepare 6 kinds of polarization quantum states

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