The invention discloses a phase compensation implementation method of a continuous variable quantum key distribution system A sender performs Gaussian modulation on initial continuous key data by using the coherent state and then sends the modulated signals to a receiver through an optical fiber channel; and the receiver performs preprocessing, error corrosion and confidentiality enhancement on the acquired initial continuous key data by using an algorithm based on orthogonal basis expansion so as to acquire the final security key According to the method, the practical use of the continuous variable quantum cryptography is prompted, and environmental interference and human attack affected by the quantum signals in the quantum communication process can also be effectively suppressed

Polarization compensation implementation method of continuous variable quantum key distribution system

The invention provides a high-speed continuous variable quantum key distribution system and a bit frame synchronization method thereof. The bit frame synchronization method comprises the following steps: Step one, a sender generates a set of special data used as a synchronous frame; Step two, the sender sends a coherent state to a receiver through a quantum channel; Step three, the receiver uses a balance homodyne detector to measure the displacement component of the coherent state; Step four, the receiver selects an appropriate alternate voltage determining threshold and a frame synchronization segment determining threshold to determine the synchronous frame according to structure information of the special data acquired through a classical channel in Step one; and Step five, synchronization fails if the receiver does not search the synchronous frame in the specified time, and the receiver needs to adjust the value of the alternate voltage determining threshold and the value of the frame synchronization segment determining threshold and reestablishes communication. According to the invention, the interference of external environmental factors to synchronization signals in the process of quantum key distribution can be effectively overcome, and synchronization between both sides of communication can be realized.

High-speed continuous variable quantum key distribution system and bit frame synchronization method thereof

The invention provides a quantum random number generator based on an amplified vacuum state. The quantum random number generator comprises an optical path module and a circuit module. The output end of the optical path module is connected with the input end of the circuit module. The optical path module comprises a laser, a beam splitter, a balanced homodyne detector, a vacuum state generator and a light amplifier. The output end of the vacuum state generator is connected with the input end of the light amplifier. The output end of the light amplifier is connected with one input end of the beam splitter. The output end of the laser is connected with another input end of the beam splitter. The output end of the beam splitter is connected with the input end of the balanced homodyne detector. The invention further provides a corresponding method. The generator generates the quantum random number through the measured and amplified vacuum state, a pseudo noise code and original ratio specific mode is used for error removal treatment, and therefore a true random number which is higher in production speed and better in randomness is produced.

Quantum random number generator based on amplified vacuum state

The invention discloses a monitoring method for a continuous-variable quantum key distribution system. The method is used for monitoring a quantum channel between a sender and a receiver of the continuous-variable quantum key distribution system. The receiver comprises a balanced homodyne detector. The balanced homodyne detector comprises a 50:50 BS and an AM. According to the non-ideality of relevance between the transmittance and the wave length of the 50:50 BS of the balanced homodyne detector, two kinds of de-noising light are introduced besides spurious signal light and spurious local oscillation light, and therefore the extra noise caused by acquiring and resending behaviors of a monitor is eliminated.

Monitoring method for continuous-variable quantum key distribution system

The invention discloses a quantum key distribution system and method based on time-slot mixed active polarization compensation The quantum key distribution system comprises a transmitting terminal, an optical signal generation module, a polarization modulator, a synchronous signal generator, a wavelength division multiplexing module, a wavelength division multiplexing solution module, a synchronous signal receiver, a polarization demodulator, a signal detection module and a receiving terminal According to the quantum key distribution system and method, adopted reference light pulse signals and quantum pulse signals have the same wavelength, the magnitude of single pulse energy of the reference light pulse signals is far larger than the magnitude of single pulse energy of the quantum pulse signals, and the magnitude can be detected through a photoelectric detector The reference light pulses do not need to be accumulated repeatedly to calculate sums when the detection is carried out, and the polarization compensation rate can be greatly promoted After the active polarization compensation, and different polarization codes are detected based on a unified polarization detection device, so the quantity of SPAD can be reduced An optical switch is utilized to carry out switchover on a detection light path, the phenomenon that the strong reference light pulse signals directly impact the SPAD, and therefore communication quality of quantum signals can be guaranteed

Quantum key distribution system and method based on time-slot mixed active polarization compensation

The invention discloses a continuous variable quantum key distribution system and a synchronous realization method thereof. The continuous quantum key distribution system consists of a light path part and a circuit control part, wherein the light path part mainly consists of a laser, an attenuator, a beam splitter, a polarization controller, am amplitude controller, a phase controller and a coupler. A control part is a transmission end controller module and consists of a true random key generator, an analog voltage output and a trigger clock output. The synchronous method comprises a bit synchronizing step and a frame synchronizing step. The invention provides a completely novel synchronous realization scheme based on properties of continuous variable quantum in an optical fiber, the practical orientation of the continuous variable quantum key distribution system is promoted, and the interference that the continuous variable quantum on the synchronous realization in the optical communication process also can be effectively overcome.

Continuous variable quantum key distribution system and synchronous realization method thereof

The invention relates to a continuous variable quantum key distribution system and a phase compensation method thereof The method comprises the following steps that: a sending end determines to send a phase compensation frame and determines a value of frequency A in an insertion signal of the phase compensation frame; the sending end sends the phase compensation frame and receives (A-1) signal frames; a receiving end samples an output signal of a coherent detector and extracts the phase compensation frame; the receiving end calculates a voltage value to be compensated according to the phase compensation frame, compensates the compensated voltage value to (A-1) key frame phases through a second phase modulator to eliminate environment and system noises and stores compensated (A-1) key frames into an original key file; the receiving end receives the subsequent phase compensation frame, extracts the phase compensation frame, and repeatedly performs the operation; and the sending end sends an interrupt transmission signal, and after receiving the interrupt transmission signal, the receiving end stops receiving, so key distribution is finished The invention has the advantages of low bit error rate and reliable communication

Shen Zeyuan

Papers

Continuous variable quantum key distribution system and synchronous realization method thereof

Continuous variable quantum key distribution system and phase compensation method thereof