604 results about "Photon detector" patented technology

The invention relates to the technical field of optical fiber monitoring and maintenance, and discloses an optical fiber monitoring method, device and equipment, a storage medium and a computer program product, and the method comprises the steps: enabling pulse light of a preset period to be coupled into a to-be-detected low-loss optical fiber based on an optical fiber amplifier and a variable optical attenuator, and generating a backward scattering light signal; converting the backward scattering light signal into an electric pulse signal by using a single-photon detector, and counting the electric pulse signal by using a preset period as a period through a synchronous clock to obtain a counting result; adjusting the power of the variable optical attenuator according to a counting result, and drawing a target signal curve of the to-be-measured low-loss optical fiber based on an adjustment result; and analyzing the target signal curve to obtain a monitoring result of the to-be-measured low-loss optical fiber. The power is dynamically adjusted in different measurement sections, and the multi-section measurement results are superposed, so that the dynamic range of the single-photon optical time domain reflectometer is remarkably expanded, and the loss and dead pixels of the low-loss optical fiber can be reflected more comprehensively and accurately.

The present invention discloses a single-photon detector refrigeration control method and system that is adaptive to temperature and TEC performance changes. The method limits the maximum operating voltage of TEC, monitors the TEC operating voltage and refrigeration temperature in real time, and automatically adjusts the target temperature and APD working bias voltage according to the monitoring results, effectively ensuring that the single-photon detector can still work stably when the working environment temperature is too high or the TEC performance is degraded. At the same time, when the ambient temperature is allowed to return to the normal temperature range, the TEC's refrigeration target temperature can be restored to the initial refrigeration target temperature and the APD's working bias voltage can be adjusted synchronously, so that the performance indicators of the single-photon detector, such as the detection efficiency, dark count rate, and after-pulse probability, will be synchronously restored to normal. In this way, the service life of TEC and single-photon detector equipment can be effectively improved, and the environmental adaptability of the single-photon detector can be improved.

The invention provides a scanning-type single-photon laser radar system based on phase regulation, and the system employs a reflection-type liquid crystal spatial light modulator to carry out the phase regulation of a laser beam, and achieves the long-distance fixed-point focusing through the modulation of laser wavefront. And echo signal detection is carried out by using a single-photon detector. Before the reflection type liquid crystal spatial light modulator is used for carrying out phase regulation and control on a laser beam, the laser beam is divided into reference light and detection light through the light splitting module, and then the divergence angle of the laser beam is reduced through the beam expanding module; after phase regulation and control, scanning of a laser beam in a target area is controlled through a reflector and a two-dimensional scanning galvanometer.

The invention discloses a single-photon laser radar imaging system and method for underwater target detection, and belongs to the technical field of detection imaging. The imaging system comprises an optical system and a control system, and the optical system comprises a transmitting unit, a receiving unit, a single-photon detector and a scanning unit. An optical path of the optical system adopts a transmitting-receiving combined optical path structure, the transmitting unit transmits an optical signal, the scanning unit receives the transmitted optical signal and a control signal and reflects an echo optical signal, the echo optical signal generated by the optical signal transmitted by the transmitting unit is received by the receiving unit, the echo optical signal is converged to the single-photon detector, and the single-photon detector is used for detecting the single-photon. The single-photon detector performs photoelectric conversion; the control system comprises an FPGA control board, and the FPGA control board is connected with a communication module, a gating signal module and a scanning signal module. The system is compact in structure and reasonable in design, detection of weak optical signals can be realized by using a reasonable optical path structure and the single-photon detector, and the farthest detection distance is increased.

The invention provides a single photon pulse laser radar target detection method and system. The method comprises the following steps: modulating pulse emission time delay by adopting a pseudo-random number function to obtain a pulse laser emission time sequence; a precise time-to-digital converter is adopted to collect output signals of the single-photon detector, the arrival time of photons is recorded, and an echo photon time sequence is obtained; the method comprises the following steps: intercepting echo photon time subsequences in a pulse laser emission time sequence according to a fixed length sequence, delaying the echo photon time subsequences in combination with an echo photon time sequence delay amount to obtain a delay subsequence, and carrying out matching counting on the delay subsequence and the echo photon time sequence to obtain a matching counting number; continuously adjusting delay to obtain a matching function; and performing threshold detection on the matching function, and calculating a target distance by taking an echo photon time subsequence delay amount corresponding to the threshold detection as pulse round-trip flight time. According to the invention, the problem of fixed pulse repetition frequency ranging ambiguity is solved.

The invention provides a single-photon avalanche diode and a single-photon detector, and relates to the technical field of semiconductor photoelectric detection, and the single-photon avalanche diode comprises a plurality of avalanche diode units. The avalanche diode units are sequentially stacked in the propagation direction of incident light to be detected. Each avalanche diode unit is provided with an electric field control module which is used for independently adjusting the bias electric field of each avalanche diode unit. In the propagation direction of the incident light, the avalanche diode unit of the next stage is used for absorbing the remaining photons which are not absorbed by the avalanche diode unit of the previous stage and generating carriers, so that avalanche current is formed. The light absorption wavelength ranges of adjacent avalanche diode units are at least partially overlapped. The single-photon avalanche diode solves the problem that the existing single-photon avalanche diode cannot balance high detection efficiency and low dark current, and achieves the purpose of improving the detection efficiency of a single-photon detector on the premise of not increasing the dark current.

The invention relates to a quantum computer, which comprises a sample (21) with paramagnetic centres, preferably in the form of NV centres (22), and a pumping radiation source (1). The pumping radiation source (1) irradiates, by means of an optical system, the paramagnetic centres and / or NV centres (22) with pumping radiation (54) of a pumping radiation wavelength (λpmp) over a first optical partial path. The optical system detects the fluorescent radiation (33) of the paramagnetic centres (22) and guides the fluorescent radiation (33) to a photodetector (50) and / or a single-photon detector (50) over a second optical partial path. The first optical partial path differs from the second optical partial path at least in some portions. The photodetector (50) and / or the single-photon detector (50) convert the fluorescent signal of the fluorescent radiation (33) of the paramagnetic centres (22) into at least one measurement signal and / or at least one measurement value. The quantum computer uses this at least one measurement signal and / or this at least one measurement value to carry out a quantum operation. The device is characterised in that the quantum computer has an optical spatial filter in the second optical partial path.

The invention relates to an optical time domain reflectometer and a control method of the optical time domain reflectometer, and relates to the technical field of photoelectricity. The optical time domain reflectometer OTDR comprises a single photon detector, and the OTDR is used for being connected with an optical fiber to be measured; the OTDR is further used for sending a plurality of detection signals to the optical fiber to be detected in sequence and receiving a plurality of detection echo signals from the optical fiber to be detected in sequence, and the detection echo signals are used for indicating the transmission state of the same section of transmission area in the optical fiber to be detected; performing amplitude reduction processing on each detection echo signal at a certain time interval to obtain a processed detection echo signal; the positions, corresponding to the same section of transmission area, of the signal sections subjected to amplitude reduction processing in the different processed detection echo signals are not completely the same; each processed detection echo signal is subjected to photoelectric conversion based on the single-photon detector to obtain a first electric signal, a first OTDR oscillogram is output based on the multiple first electric signals, and the first OTDR oscillogram is used for indicating the transmission state of the same section of transmission area. Therefore, the problem of OTDR curve distortion can be solved.

The invention relates to the field of computational imaging, in particular to a computational imaging method of a crossed strip-shaped anode single-photon detector, which comprises the following steps of: screening effective data through full-view-field illumination, and calculating an average output signal amplitude of each anode strip and a total average output signal amplitude of all anode strips to obtain a correction factor; the method comprises the following steps of: correcting an original output signal of each anode strip by adopting a correction factor during target imaging, performing effective signal data screening on the corrected original output signal, substituting effective signal data into a Gaussian algorithm to calculate an incidence position coordinate, mapping the incidence position coordinate to a mapping matrix, and stretching the incidence position coordinate to a 256 gray level for display. According to the calculation imaging method provided by the invention, the fixed mode noise can be suppressed, the imaging resolution is improved, and the image distortion is reduced.

The invention relates to the field of LED display screen defect detection, in particular to an LED display screen defect rapid detection method. The method specifically comprises the steps that polarization entangled photon pairs are generated through a first detection assembly, the photon pair coincidence counting rate is measured through an HOM interferometer and a single-photon detector in a second detection assembly, and a photon pair anomaly distribution diagram is generated; establishing a correlation model of the photon pair coincidence counting rate and the electronic state density, and analyzing internal defects of the display screen; an integrated high-speed CMOS camera and a multiband LED annular light source are adopted to collect four-channel image data, and features are extracted to generate an image data abnormal probability graph; and finally, integrating a quantum optical measurement result and an image analysis result through coordinate mapping, judging a final defect area and type based on a decision tree rule, and covering various defect types such as material internal defects, surface reflection abnormity and color unevenness. According to the method, the efficiency and the accuracy of LED display screen defect detection are remarkably improved.

Systems and methods include acquisition of an anatomical image of an object, acquisition of molecular imaging data of the object at the plurality of photon detectors, reconstruction of a functional image based on the molecular imaging data, input of the anatomical image and the functional image to a trained neural network to generate a second functional image, and presentation of the second functional image.

The invention discloses a single-photon three-dimensional imaging system based on double-optical-wedge scanning and a registration method. According to the single-photon three-dimensional imaging system based on double-optical-wedge scanning, multi-beam emission illumination based on Dammann gratings is adopted, so that the energy utilization efficiency can be effectively improved, and the detection distance is increased; by adopting the area array single-photon detector, high-sensitivity detection of extremely weak long-distance target reflected light signals can be realized; an imaging view field can be expanded under the condition that image rotation is not introduced by adopting a double-optical-wedge scanning mode; internal reflection can be effectively inhibited and a close-range detection blind area can be eliminated by adopting sub-aperture common-path coupling; a prior-based rapid reconstruction algorithm is adopted, so that the three-dimensional image reconstruction speed of double-optical-wedge scanning can be effectively improved; by adopting an off-axis focal plane method, high-efficiency coupling registration of emitting laser beams and receiving the field of view of the area array detector can be realized.

The invention discloses a signal synchronization method and system based on a free space quantum key distribution system, and belongs to the technical field of key transmission. A high-power synchronous laser is adopted as a synchronous light source, a preset frame identification head is adopted to modulate a synchronous light signal, the modulated synchronous light signal serves as reference light and is sent to a receiving end, then synchronous coding is conducted on the synchronous signal received by a synchronous detector of the receiving end, and position information of the synchronous signal is generated and sent to a single photon detector of the receiving end; and performing sequence correspondence on the quantum signal received by the single-photon detector at the receiving end and the synchronizing signal according to the position information to finish signal synchronization. Frame synchronization is achieved through the synchronous laser, bit synchronization is achieved through synchronous coding and sequence correspondence, interference of an atmospheric channel can be effectively resisted, and the bit error rate of the system is reduced.

The invention discloses an infrared dual-band single-photon laser radar imaging system, and belongs to the field of laser radar detection. The system comprises an infrared dual-band light source, a beam splitter, a first delay line, a light splitting module, a transceiver module, a frequency up-conversion module, a photoelectric detector, a single-photon detector, a signal acquisition module and a signal processing module. The infrared dual-band light source generates near-infrared and intermediate-infrared pulse laser; near-infrared laser is used for near-infrared detection, frequency up-conversion pumping and initial signals after passing through a beam splitter, intermediate-infrared laser is used for intermediate-infrared detection, intermediate-infrared detection signal echoes are subjected to time domain gating and frequency up-conversion by near-infrared pumping signals and then injected into a single-photon detector together with near-infrared detection signal echoes through time division multiplexing, and the intermediate-infrared detection signal echoes and the near-infrared detection signal echoes are subjected to frequency up-conversion. And detection imaging is realized through signal acquisition and processing. According to the invention, the weak target detection imaging capability of the single-photon laser radar in environments of gas, strong background noise and the like can be improved, and the multi-band sensing capability of the radar on target characteristics is improved.

The invention discloses a single-photon non-vision-field target tracking system based on an unmanned aerial vehicle platform, which belongs to the field of non-vision-field imaging and is characterized in that a laser is connected with a scanning galvanometer assembly through a first nanosecond optical path switch and an optical fiber circulator to form an emission optical path for emitting laser pulses to relay reflecting surfaces corresponding to four predetermined positioning points; the scanning galvanometer assembly is connected with the photon detector through the collimating optical fiber, the optical fiber circulator and the second nanosecond optical path switch to form a receiving optical path capable of receiving echo photons; the main control module is electrically connected with the laser, the first nanosecond light path switch, the second nanosecond light path switch, the scanning galvanometer assembly, the photon detector, the time-to-digital converter and the high-frequency inertial measurement unit respectively, and can control each component to perform laser ranging, double-window gating, single-photon detection, inertial measurement unit sampling and timing according to a unified time sequence; and the three-dimensional coordinates of the current non-vision target are calculated by using the distance measurement data through an ellipsoid intersection solution method, so that non-vision target tracking is realized.

The invention relates to the technical field of light quantum metering, in particular to a multifunctional standard single photon source generation and calibration device and a use method, and the device comprises a pumping laser light source, a nonlinear crystal, a signal optical filter, a beam splitter, a temperature control module, an idler frequency optical filter, a control module, a single photon detector group, a beam splitter, a multi-channel coincidence counter, and an optical switch. The pumping laser light source pumps the nonlinear crystal to generate two paths of single photon output of signal light and idler frequency light, the two paths of single photon output are filtered by the filter and then divided into multiple paths by the beam splitter, and standard single photons are directly output or the paths of the signal light or the idler frequency light are controlled by the optical switch to enter the single photon detector group for detection. External input single photons are controlled by the optical switch to enter the single-photon detector group for detection, and a count value of the single-photon detector group is accessed to the multichannel coincidence counter to record data. A pump light stable power system and a multi-path beam splitting coincidence counting system are introduced into a light path, so that standard single photon output with known brightness and g (2) (0) value can be realized.

The invention discloses a ranging communication fusion miniaturized system and method based on single photon detection. The system adopts a time division multiplexing common-path structure, and a ranging pulse sequence and a communication pulse sequence are sequentially transmitted in the same detection period to form a PPM modulation laser pulse chain. A single-photon detector is adopted to receive signals, background light interference is suppressed by combining a narrow-band filter and a time gating technology, and the type and boundary of a pulse sequence are identified through a signal demodulation and discrimination module. When the distance measurement pulse sequence is identified, the distance measurement path realizes distance measurement based on the round-trip time of the distance measurement pulse in the period; when a communication pulse sequence is identified, the communication path demodulates the PPM communication data. The method effectively decouples the contradiction between the distance measurement fuzzy and the communication rate, supports communication pulse high repetition frequency modulation while realizing non-fuzzy distance measurement, improves the distance measurement precision and the communication rate, and is suitable for free space communication, mobile robot platforms and other application scenes.

The invention discloses a side slope displacement monitoring method and device based on quantum single photons and a medium, and belongs to the technical field of displacement monitoring. Rectangular light pulses are emitted periodically, echo detection is completed by using a single photon detector, a photon counting time sequence is constructed, wavelet denoising and reconstruction processing is performed on the photon counting time sequence, main peak position offset, energy change and form distortion are extracted to match multiple types of feature vectors, and feature fusion and resolving are performed through a multi-source feature fusion BP neural network. And finally outputting a high-precision slope displacement result. According to the method, the quantum single-photon detection technology is combined with the wavelet denoising and neural network fusion algorithm, noise interference is effectively suppressed, the displacement feature extraction precision is improved, and the method is suitable for high-precision and long-distance slope micro-deformation real-time monitoring.

According to the single-photon laser multispectral polarization detection method and system under underwater turbulence disturbance provided by the invention, pulse laser is emitted to a target after being scanned, and weak echoes of the pulse laser are received by a double-photon detector and a single-photon detector after being subjected to spectral filtering and spatial polarization beam splitting. A time correlation single photon counting technology is adopted, time, polarization and wavelength information of each photon is recorded synchronously, and a multi-dimensional data set is generated in combination with a scanning angle. After turbulence noise is suppressed through preprocessing, target distance information is extracted to generate a three-dimensional point cloud, and the polarization degree and the depolarization ratio of each pixel point are calculated; and finally, geometric, polarization and spectral data are fused, a high-precision three-dimensional terrain and polarization image is generated, and accurate target identification in a complex underwater environment is realized. According to the invention, a set of multi-dimensional information sensing system capable of carrying out long-distance, high-resolution and high-precision classification and identification on a target in a complex underwater environment with strong attenuation, strong noise and strong turbulence disturbance is constructed.

The invention discloses a zero-dead-time single photon counting system based on time division multiplexing, and belongs to the technical field of laser radars. The system comprises an optical multiplexer, N detection channels, N delay modules, a shift register and a counting circuit, according to a time division multiplexing mechanism, a time axis is divided into a plurality of independent time slots, and in different time slots, incident signal light is input into different detection channels according to a preset sequence, so that zero-dead-time single photon counting is realized. According to the invention, the dead time problem of a traditional single-photon detector is solved, the photon counting pulse and the dark current pulse are effectively distinguished through a multi-parameter pulse discrimination technology, the signal-to-noise ratio of the system is significantly improved, and a reliable solution is provided for application scenes requiring high-sensitivity detection, such as laser radar and quantum communication.

Improvements in and relating to Photonics An optical switch for receiving an optical signal from an optical signal source and for outputting the optical signal comprises an optical router configured for routing the optical signal conditional on the detection of a single photon. The optical router comprises and optical resonator, a first optical pathway part comprising the optical resonator, and a second optical pathway part. An optical input coupling part receives the optical signal for coupling the received optical signal into the first optical pathway part and into the second optical pathway part. An optical modulator coupled to a single-photon detector unit outputs a detection signal in response to the detection of a single photon. The optical modulator is configured, in response to the detection signal, to modulate the refractive index of the optical resonator to change an optical phase shift incurred by the optical signal upon passage through the optical resonator such that an optical interference results in a routing of the output optical signal to one of the first and second optical pathway parts selected conditional on the detection of a single photon.

The invention relates to the technical field of single-photon detection, in particular to a single-photon detector performance parameter measurement method, device and equipment and a storage medium, and the method comprises the steps: building a statistical histogram of time domain interval data, and building the statistical distribution characteristics of the photon counting rate and dark counting of a single-photon detector; the probability of no photon detection event in the duration of the optical pulse and the ideal probability of no dark pulse in a preset time window are defined based on the statistical distribution characteristics, and then the probability of generating a single photon signal by the periodic optical pulse is calculated based on the obtained parameters; and finally, determining a periodic statistical peak count value based on the statistical histogram and the probability of generating the single photon signal by the periodic light pulse, and calculating an average detection photon number and a dark count rate so as to obtain the dead zone time, so that information such as the average detection photon number, the dark count rate and the dead zone time of the single photon detector is simultaneously represented through one-time data acquisition, and the detection accuracy of the single photon detector is improved. The problems that in a traditional method, the data storage amount is large, and cost is high are solved.

The invention discloses a method for representing the detection efficiency of a sine-gated single-photon detector by using continuous light. The method comprises the following steps: collecting count values of the single-photon detector under different bias voltages; calculating an initial gate width, an initial average photon number and initial detection efficiency according to the initial over-bias voltage; increasing the bias voltage by a step value, calculating widths of different parts of gate pulse detection efficiency under the voltage, and calculating count values of the different parts; subtracting the count value measured under the bias voltage from the sum of the count values of all the parts to obtain a corrected count value, and calculating the detection efficiency; whether the bias voltage reaches a set maximum value or not is judged, if not, the bias voltage continues to be increased, and meanwhile the detection efficiency is corrected; and if the maximum value is reached, the detection efficiency obtained through processing is used as a final calibration value. The method can correct the detection efficiency when a continuous light source is used, and eliminates the influence of a plurality of voltage intervals, so as to calibrate the maximum detection efficiency of the detector.

The invention provides a silicon carbide single-photon detector and a preparation method thereof, and relates to the technical field of silicon carbide solar blind detection. The silicon carbide multiplication layer and the aluminum gallium nitrogen absorption layer of different material systems are sequentially grown on the silicon carbide substrate, and the side, far away from the silicon carbide substrate, of the aluminum gallium nitrogen absorption layer is the light incidence side, so that incident light firstly passes through the aluminum gallium nitrogen absorption layer and is excited to generate current carriers, and then the current carriers are multiplied by the multiplication layer to generate internal gain, so that the light emitting efficiency is improved. The detection sensitivity is improved. The forbidden bandwidth range of the aluminum gallium nitrogen absorption layer coincides with the photon energy range of the solar-blind wave band, so that the aluminum gallium nitrogen absorption layer only absorbs the solar-blind wave band and transmits the wave band outside the solar-blind wave band, absorption of photons outside the solar-blind wave band when a silicon carbide absorption layer is adopted is avoided, light filtering in a light filter mode is also avoided, and the detection responsivity is improved.

Quantum teleportation is essential for many quantum information technologies, including long-distance quantum networks. Using fiber-coupled devices, including state-of-the-art low-noise superconducting nanowire single-photon detectors and off-the-shelf optics, we achieve conditional quantum teleportation of time-bin qubits at the telecommunication wavelength of 1536.5 nm. We measure teleportation fidelities of ≥90% that are consistent with an analytical model of our system, which includes realistic imperfections. To demonstrate the compatibility of our setup with deployed quantum networks, we teleport qubits over 22 km of single-mode fiber while transmitting qubits over an additional 22 km of fiber. Our systems, which are compatible with emerging solid-state quantum devices, provide a realistic foundation for a high-fidelity quantum Internet with practical devices.

The invention relates to the technical field of photon detection imaging, in particular to a deep learning-based crossed strip-shaped anode single-photon detector imaging method, which comprises the following steps of: enabling incident photons to enter a crossed strip-shaped anode single-photon detector to obtain charge signals on a crossed strip-shaped anode in the detector; sampling the charge signal; inputting the obtained sampling data into a trained decoding network model to obtain a predicted position of an incident photon; establishing an imaging matrix, mapping the obtained prediction position into the imaging matrix, and performing interval division on the mapped imaging matrix; and carrying out gray value mapping on the number of photons in the divided intervals to obtain an imaging result. According to the invention, the neural network model is introduced to carry out computational imaging, so that the imaging quality of the cross strip-shaped anode single-photon detector is improved.

The invention discloses a quantum key distribution system based on PZT phase modulation and a PZT phase correction method. The method specifically comprises the following steps: determining expected working voltages of a first PZT and a second PZT; dynamically adjusting the working voltage of the first PZT based on the current detection error rate of the first zero-beat single-photon detector SPD or the second zero-beat single-photon detector SPD and the deviation distance between the current working voltage of the first PZT and the expected working voltage; and dynamically adjusting the working voltage of the second PZT based on the detection error rate of the third zero-beat single-photon detector SPD or the fourth zero-beat single-photon detector SPD and the deviation distance between the current working voltage and the expected working voltage of the second PZT. The PZT is used as the phase modulator, phase modulation is performed on light quantum, passive decoding is performed according to the response of the detector, the phase modulator does not need to participate in modulation, high-speed quantum random number resources of 2bit / photon are reduced, and the practical application cost and difficulty of the high-speed quantum key distribution system are greatly reduced.

The invention discloses a quantum random number generation device, a chip and a quantum random number generation method, and belongs to the technical field of random number generation. The device comprises: a light source for emitting a photon stream to an optical waveguide; the optical waveguide is used for attenuating the number of photons of the photon flow and outputting the photons to the photon detector; the photon detector is used for receiving the photons output by the optical waveguide, generating pulse signals based on the arrival time of the photons and sending the pulse signals to the data processing equipment; and the data processing equipment is used for generating the quantum random number according to the pulse signal. By utilizing the optical characteristics of the optical waveguide, the number of photons reaching the photon detector after the photon flow passes through the optical waveguide is reduced, compared with the mode of attenuating the number of photons through a free space optical path and optical element combination, the size of the optical waveguide is smaller, and the optical waveguide is more suitable for being integrated with a silicon chip; therefore, the occupied space of the quantum entropy source can be reduced, and the miniaturization and chip development of the quantum random number generator is promoted.

The invention provides a linear optical quantum amplifier based on coding in time modes, which comprises a first photon detector and a second photon detector in two time modes, and an input end beam splitter, a first beam splitter, a second beam splitter and an output end beam splitter, the first photon detector is used for detecting photons appearing in a first time window of the upper path, and the second photon detector is used for detecting photons appearing in a second time window of the lower path; the input end beam splitter and the output end beam splitter completely transmit photons emitted in a first time window and completely reflect photons emitted in a second time window at the same time, the first beam splitter completely reflects the photons emitted in the first time window and reflects the photons emitted in the second time window with the reflectivity of gamma, and the second beam splitter completely reflects the photons emitted in the second time window with the reflectivity of gamma. And the first beam splitter completely reflects the incident photons in the first time window and transmits the incident photons in the second time window by a transmission coefficient of 1-gamma, the second beam splitter completely reflects the incident photons in the second time window and reflects the incident photons in the first window by a reflectivity of gamma, and the first beam splitter transmits the incident photons in the first time window by a transmission coefficient of 1-gamma. The method is more concise, easy to operate and better in amplification effect, and a large number of sub-state amplification protocols are achieved.

A quantum key distribution system is provided, including: a sending terminal, a measurement terminal, a receiving terminal, and at least one polarization controller. The sending terminal is configured to generate a quantum optical signal and receive a detection result. The measurement terminal includes a beam splitter and two single-photon detectors, the beam splitter is configured to generate two measurement optical signals based on the quantum optical signal, and the two single-photon detectors are configured to generate the detection result. The receiving terminal is configured to receive the detection result. The at least one polarization controller is provided in the sending terminal, the measurement terminal or the receiving terminal, and performs a polarization processing on the quantum optical signal or the detection result using a target transmittance matrix determined based on the detection result, so as to obtain a polarized quantum optical signal or a polarized detection result.