Quantum coder and decoder of phase modulated polarizing state and its application method

A phase modulator and quantum coding technology, which is applied in photonic quantum communication, instruments, electromagnetic wave transmission systems, etc., can solve the problems of incompensability, high bit error rate, and half efficiency, etc., achieve high-precision polarization compensation, and reduce bit errors rate effect

Inactive Publication Date: 2004-02-25
SOUTH CHINA NORMAL UNIVERSITY
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Problems solved by technology

[0003] The BB84 protocol usually adopts the phase modulation encoding method, that is, two identical Mach-Zehnder interferometers are used as the encoder and decoder. The bit error rate of this encoding method is mainly determined by the interference contrast ratio of the Mach-Zehnder interferometer in addition to the electrical noise. decision, and the contrast of the reference is determined by the coherence of light, because the coherence of light is inevitably destroyed in the process of modulation and transmission, and once the coherence is destroyed, it cannot be compensated, so the bit error of this coding method relatively high rate
[0004] Although the BB84 protocol can also be implemented using four non-orthogonal linear polarization states or a four-state encoding method of two linear polarizations plus two circular polarization states, there is still no breakthrough in technology.
[0005] The B92 protocol usually has two methods of phase modulation and polarization modulation. The phase modulation coding method is basically the s

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  • Quantum coder and decoder of phase modulated polarizing state and its application method
  • Quantum coder and decoder of phase modulated polarizing state and its application method
  • Quantum coder and decoder of phase modulated polarizing state and its application method

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Example Embodiment

[0031] Example 1: Using a four-state quantum encoder and decoder for quantum secure communication of the BB84 protocol

[0032] For the first time, we have realized the quantum secure communication of the BB84 protocol with the 4-state encoding method of "two linear polarization states plus two circular polarization states" experimentally. The light path is like image 3 As shown, the method is as follows: Alice uses a four-state quantum encoder to randomly prepare four non-orthogonal polarization state photons, and transmits them to Bob through an optical fiber, and Bob uses a four-state quantum decoder to randomly generate four sets of non-orthogonal polarization state measurements Based on the detection of the four non-orthogonal polarization state photons sent by Alice, when the photon is detected, Bob sends the used measurement basis to Alice through the common channel, and Alice tells Bob which measurement basis is correct, and then Alice Keep the corresponding bits when the...

Example Embodiment

[0033] Embodiment 2: A six-state quantum encoder and decoder are used for quantum secure communication of six-state encoding.

[0034] We used the six-state encoding method for six-state quantum secure communication for the first time. Figure 5 As shown, Alice uses a six-state quantum encoder to randomly prepare six non-orthogonal polarization state photons, and transmits them to Bob through an optical fiber. Bob uses a six-state quantum decoder to randomly generate six non-orthogonal polarization state measurement basis. The six non-orthogonal polarization state photons sent by Alice are detected. When the photon is detected, Bob sends the used measurement basis to Alice through the common channel. Alice tells Bob which measurement basis is correct, and then Alice and Bob keep it When the measurement base is consistent, the corresponding bits are discarded, and other data is discarded. Bob will publish some bits for Alice to confirm whether there are errors. Finally, after Alice ...

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Abstract

The present invention relates to a quantum coder and decoder with phase modulated polarization state and their application method in the quantum secure communication. Four-state quantum coder or decoder is formed from a phase-polarization controller and a ture random generator, and can implement quantum secure communication using "two linear polarization states and two circular polarization states" four-state coded BB84 protocol; and six-state quantum coder or decoder is formed from two phase-polarization controllers and a synchronous trigger, and can implement six-state coded quantum secure communication.

Description

technical field [0001] The invention relates to special equipment for quantum secure communication in the communication field and an application method thereof, in particular to a quantum encoder and decoder for phase modulation polarization state and an application method for quantum secure communication. Background technique [0002] In the existing quantum secure communication technology, there are three types of protocols such as BB84 protocol, B92 protocol and E91 protocol, and three coding methods such as two-state coding, four-state coding and six-state coding. The BB84 protocol belongs to the four-state coding method, while the B92 protocol and the E91 protocol belong to the two-state coding method. The efficiency of the four-state coding method is relatively high, while the efficiency of the two-state coding method is halved. [0003] The BB84 protocol usually adopts the phase modulation encoding method, that is, two identical Mach-Zehnder ...

Claims

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Application Information

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IPC IPC(8): G02F1/00H04B10/70H04K1/00H04L9/08
Inventor 唐志列廖常俊刘颂豪
Owner SOUTH CHINA NORMAL UNIVERSITY
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