24 results about "Homodyne detection" patented technology

The invention provides a passive laser gyroscope based on a light force induced transparency effect and a measurement method thereof, the passive laser gyroscope comprises a frequency stabilized laser light source, a signal modulation input device, a balance homodyne detection device, an annular optical resonant cavity and a signal detection and feedback device, wherein a reflection cavity mirror with a photomechanical resonance structure characteristic is integrated in the annular optical resonant cavity; according to the passive laser gyroscope, a narrow transparent window modulated by a mechanical damping rate is generated on an annular optical resonant cavity of the passive laser gyroscope by utilizing a light force induced transparency effect and a light-mechanical coupling effect, so that the quality factor of the annular optical resonant cavity is improved, and the measurement sensitivity of the passive laser gyroscope is enhanced.

The present disclosure relates to a system and a method of performing Gaussian boson sampling via time multiplexing correlation of squeezed vacuum states for quantum information experiments. One embodiment relates to a method for performing Gaussian boson sampling comprising the steps of—generating a set of pulsed pairs of squeezed vacuum states,—performing time 2024 / 038212 multiplexed correlation of multiple of such pairs of squeezed vacuum states,—measuring, via a homodyne detection, a state from the pairs of generated squeezed vacuum states,—feed-forwarding the homodyne result of the measured states to a displacement unit,—performing displacement operations on the remaining state from the pairs of generated squeezed vacuum states, and—counting the states output from the displacement unit.

An entanglement-assisted multistatic quantum radar detection technique employs the integrated entangled source shared among multiple transmitters and performing transmit side optical phase conjugation. EA receivers are based on classical homodyne detection schemes. The EA multistatic radar detection technique is evaluated against bistatic radar EA detection scheme and various coherent states-based quantum detection schemes (the optimum quantum detector. Helstrom threshold detector, and random phase optimum quantum detector). The EA multistatic target detection probability is significantly better than that of corresponding bistatic radar EA detection techniques. coherent states-based quantum detection techniques. and the classical radar detection schemes. When both scattered signal photon channels and idler channels are noisy and lossy, the scheme significantly outperforms the EA bistatic radar scheme.

A quantum random number generation (QRNG) system includes a single-photon or equivalent single-photon light source; a beam splitter arranged to direct output from the light source to a first homodyne detector having a first local oscillator and a second homodyne detector having a second local oscillator; and a signal control and processing unit. The signal control and processing unit is configured to: vary phases of the first and second local oscillators; receive a plurality of measurements of output from the first and second homodyne detectors, the plurality of measurements dependent on intensity of the light source and the phases of the first and second local oscillators; determine from the plurality of measurements whether a CHSH inequality is satisfied; and output one or more random numbers in dependence on whether the CHSH inequality is satisfied.

This invention provides a large-scale, high-precision optical Ising computer that can significantly increase the number of spins, achieve optimal binary bifurcation for the problem to be solved using an arbitrary nonlinear function, and converge stably and quickly. [Solution] The system includes a pulse light source 1, an optical fiber loop 3 into which optical pulses from the pulse light source 1 are introduced, an erbium-doped optical fiber amplifier 4 provided within the optical fiber loop 3, a homodyne detection circuit 5 for detecting optical pulses from the optical fiber loop 3, a matrix-nonlinear calculation circuit 6 for digitally calculating an interaction function and a nonlinear function for binary branching for the optical pulses detected by the homodyne detection circuit 5, and an AM optical modulator 2 which receives the optical pulses from the pulse light source 1 and the information obtained from the digital calculations of the matrix-nonlinear calculation circuit 6, modulates the input optical pulses, and then injects them into the optical fiber loop 3.

The atom magnetometer based on homodyne and differential detection is provided for the first time, detection light is divided into signal light and reference light through a 1 * 2 polarization-maintaining optical fiber coupler, and the signal light enters a gas chamber and interacts with polarized alkali metal atoms to induce magnetic field information; the reference light is subjected to high-frequency phase modulation and then subjected to homodyne coherent frequency mixing with the signal light to generate orthogonal phase signals, magnetic field information is extracted from the two paths of orthogonal signals through a homodyne and differential fusion detection mechanism, response signals are improved, low-frequency noise is suppressed, and the measurement precision, signal response and low-frequency sensitivity of the atom magnetometer are improved. Compared with a traditional single differential detection method, the phase sensitivity characteristic of homodyne detection and the common-mode noise suppression capability of differential detection are innovatively combined, and enhancement and high-fidelity extraction of detection signals and suppression of low-frequency noise are achieved through coherent demodulation and differential processing of double-path polarization modulation signals.

An optical fiber characteristics measurement apparatus includes a first optical splitter that splits modulated light into pump light and reference light, a second optical splitter that causes the pump light to be incident on a fiber under test from one end and extracts Brillouin scattered light generated within the fiber under test, an adjuster that changes frequency of at least one of the reference light and pump light to a plurality of frequencies, and a calculator that measures characteristics of the fiber under test based on a second harmonic component among frequency components of a signal yielded by homodyne detection of interference light between the Brillouin scattered light and the reference light at each frequency, the second harmonic component having a frequency that is two times the modulation frequency of the modulated light.

The present disclosure discloses a method and a system for generating verifiable quantum random numbers. The present disclosure uses continuous variable systems and homodyne detection to produce verifiable quantum random numbers. A plurality of analog to digital converter circuits are used to generate sequences of random number, which can be verified for violation of a Bell-CHSH inequality. The Bell-CHSH inequality is used to ensure true quantum nature of the generated random numbers.

The application provides an optical phase measurement method based on phase-sensitive non-Hermitian four-wave mixing, comprising generating a phase-sensitive non-Hermitian four-wave mixing process; detecting signal light and idler light emitted in the four-wave mixing process to obtain measurement results of a type-1 entanglement criterion and a type-2 entanglement criterion, and using the measurement results of the type-1 entanglement criterion and the type-2 entanglement criterion to realize measurement of an optical phase. The application uses a principle mechanism of the phase-sensitive non-Hermitian four-wave mixing process, and through non-Hermitian characteristics and optical phase sensitivity of the phase-sensitive non-Hermitian four-wave mixing process, measurement of a type-1 entanglement criterion is used to realize high-sensitivity optical phase measurement, and the application has the advantages of high robustness and higher sensitivity. The optical phase measurement method based on the phase-sensitive non-Hermitian four-wave mixing process has the advantage of high feasibility in realizing high-sensitivity optical phase measurement in combination with existing homodyne detection technology.

The application discloses a microwave continuous variable quantum key distribution method and system, and relates to the technical field of quantum key distribution. The method comprises the following steps: a transmitting end performs Gaussian modulation on a coherent state of a microwave frequency, and couples the Gaussian modulation coherent state into a free space quantum channel; a receiving end performs homodyne detection on the received Gaussian modulation coherent state, and obtains a canonical component; the receiving end broadcasts a detection basis of each Gaussian modulation coherent state on an authenticated classical channel, the transmitting end retains the canonical component corresponding to the same detection basis as the receiving end, and determines N pairs of original keys according to the retained canonical component and the canonical component obtained by the receiving end; then, the N pairs of original keys are segmented into small blocks with a fixed size, and an isolation forest algorithm is used to remove abnormal small blocks in all the small blocks; and finally, both communication parties perform a post-processing protocol on the remaining small blocks through the classical channel, and obtain a secure key. The method solves the problem of short communication distance of microwave CV-QKD in the prior art.

A system has a firewall ingress node carrying network traffic. An attack injector creates a network attack flow on the firewall ingress node and thereby forms with the network traffic a composite firewall input signal on the firewall ingress node. A firewall egress node carries a response signal corresponding to the composite firewall input signal. A network monitor is connected to the firewall ingress node and the firewall egress node. The network monitor includes a homodyne detector to multiply the response signal by an oscillating driver signal to form a product that is integrated over time to form a homodyne detector response signal that is larger when the homodyne detector response signal has some component with the same frequency as the oscillating driver signal.

The application belongs to the technical field of optical precision measurement, and discloses a kind of light beam displacement measurement method and device based on optical resonant cavity mode selection enhancement, device includes: laser light source system, spatial mode selection system and balanced homodyne detection system;Laser light source system is used to produce high purity HG 00 Mode as the first probe light field and HG 10 Mode as local light field;First probe light field is obtained after the reflection of second probe light field and is incident to spatial mode selection system after being measured surface reflection;Spatial mode selection system adopts optical resonant cavity to be resonant locked to carrier light field, to filter out the carrier component in second probe light field, and the purified light field is incident balanced homodyne detection system, balanced homodyne detection system is used for the homodyne detection of second probe light field and HG 10 Mode local light field, obtains displacement signal.The application can reduce the influence of carrier light field on measurement noise, improve the precision of light beam displacement measurement.

The application provides a quantum key distribution system based on multi-classification learning detection and an implementation method thereof, comprising a sending end Alice, a receiving end Bob and a post-processing program module based on multi-classification learning; the sending end Alice modulates a quantum signal by using a Gaussian modulation method, and sends the modulated quantum signal to the receiving end Bob through a quantum channel; the receiving end Bob is a quantum key receiving end Bob, uses a homodyne detector to measure the received quantum signal, uses a power meter to measure the intensity of the local oscillator, uses a clock circuit to provide a clock signal, and finally sends the quantum signal data to the post-processing program module based on multi-classification learning through a classical quantum channel; the post-processing program module based on multi-classification learning analyzes and processes the quantum signal data to generate a final secure key. The application can detect various quantum hacker attacks on the continuous variable quantum key distribution system, thereby enhancing the security of the continuous variable quantum key distribution system under Gaussian modulation.

The application discloses a self-evaluation quantum random number generation system and method based on heterodyne detection, which comprises the following steps: a heterodyne detection-based method is used to simultaneously extract two corresponding orthogonal component fluctuations of a quantum state as an entropy source of a random number generator; original data of a two-component measurement are randomly extracted based on a synchronous clock to reconstruct a quantum state phase space distribution in real time, so that the safety of the entropy source is comprehensively evaluated, and then the evaluation result is fed back to a hardware hash post-processing link, the size of a Toeplitz matrix constructed in an FPGA is adjusted in real time, and the real-time safety of the generated quantum random number is ensured; meanwhile, on the basis of simultaneously extracting two orthogonal component quantum fluctuations of a quantum state as an entropy source, multiple high-frequency quantum sideband modes in a balanced homodyne detection bandwidth are extracted as sub-entropy sources in parallel for the two orthogonal components, so that the quantum random number generation rate is doubled in a double-parallel quantum entropy source extraction mode.

The application relates to an electrically controlled phase-shifting device for quantum homodyne detection and a phase shift regulation method thereof, which comprises a first beam splitter, a first interference arm, a second interference arm and a second beam splitter; inputted signal light is split into two beams of signal light by the first beam splitter, one beam of signal light passes through the first interference arm to obtain signal light subjected to phase shift / frequency shift, and the other beam of signal light passes through the second interference arm to obtain signal light not subjected to phase shift / frequency shift; the signal light subjected to phase shift / frequency shift and the signal light not subjected to phase shift / frequency shift are respectively inputted into the second beam splitter and then split into two beams of output light; the frequency difference Delta f s of the signal light generated by the first interference arm is adjusted to regulate the optical phase shift of the electrically controlled phase-shifting device; and the frequency shift amount of the acousto-optic crystal is controlled by the driving frequency, and the fine frequency regulation capability of a digital frequency synthesizer is combined to realize high-precision frequency control of the optical phase shift amount.

The present disclosure includes a reception apparatus performing homodyne detection of a first beam transmitted from a transmission apparatus by using a second beam transmitted from the transmission apparatus and having an optical intensity higher than the first beam, and detecting a peak position, which is a timing at which there is a local maximum or a local minimum in an amplitude of a signal obtained by the homodyne detection.

The application provides a low-noise angular rate sensor based on a squeezed light field injection, wherein a laser light source is used to generate a squeezed light field, a coherent light field and a local light field through an optical path structure; the squeezed light field and the coherent light field are coupled to form a mixed light field, and then a Sagnac effect is generated in a corresponding optical path structure, so that a light field carrying rotation speed and squeezed angle offset information is formed; the local light field is used for balanced homodyne detection together with the light field, and mixed information in the form of an electric signal is obtained; the mixed information is output to a rotation speed information and a squeezed angle control signal through a squeezed angle matching system; and the squeezed angle control signal is used for controlling a squeezed angle of the squeezed light field. The squeezed light field is injected into a vacuum end of a fiber optic gyroscope coupler, so that the limit of shot noise can be broken, the performance of the fiber optic gyroscope is optimized, and the squeezed angle can be matched with the working state of the fiber optic gyroscope in real time through a squeezed angle adjusting system, so that the fiber optic gyroscope can output a low-noise signal in real time during working, and the precision of the fiber optic gyroscope is further improved.

The application discloses a spectrum analyzer and a spectrum detection method based on homodyne detection. The spectrum analyzer comprises a tunable laser, two 50:50 beam splitters, a fixed phase modulation module, a controller, a data processing module and two homodyne detection modules. The laser beam output by the tunable laser is a local oscillation light. The two 50:50 beam splitters correspondingly split a to-be-detected light and the laser beam. A group of to-be-detected split light beams and a group of laser light pulses are directly input into one homodyne detection module. Another group of to-be-detected split light beams and a group of laser light pulses modulated by the fixed phase modulation module are input into another homodyne detection module. The fixed phase modulation module makes the phase difference between the input laser light pulses and the output laser light pulses be pi / 2 or 3pi / 2. The two groups of homodyne detection modules respectively coherently detect the laser light pulses and the to-be-detected split light beams input thereon and amplify the detection signals. Finally, the to-be-detected light intensity corresponding to each tunable laser beam wavelength is obtained.

The present application relates to a kind of microwave measurement high sensitivity readout system of Rydberg atom pumping system, belong to microwave measurement technical field.The system utilizes the technical means of optical amplification, combines balanced homodyne detection and balanced heterodyne detection technology, by controlling the frequency of local oscillator light I and local oscillator light III, the sensitivity of microwave measurement system is improved and the readout of phase information is realized, greatly simplifies the engineering difficulty and control difficulty of system, provides new technical method for the measurement of high sensitivity microwave signal and the readout of microwave signal phase information.

The application discloses a kind of quantum secure direct communication methods based on one-time one secret mode, belong to quantum communication technical field, including the following steps: Bob prepares a batch of coherent state and sends to Alice through quantum channel, Alice will received coherent state be divided into two groups, to one group is executed homodyne detection, and detection result is sent to Bob, and Bob carries out safety detection according to the first effective information quantity;Alice encodes coherent state according to secret information, and sends to Bob after encoding, Bob randomly selects one coherent state and executes homodyne detection, and result is sent to Alice, and Alice carries out safety detection according to the second effective information quantity;Bob executes homodyne detection to the rest of coherent state and calculates threshold value, and demodulation is obtained secret information;The application uses continuous variable quantum state, easy to produce and detect, small in transmission process loss, high security, can be compatible with standard telecommunication technology.

The invention provides a low-noise angular rate sensor based on compression state light field injection. The low-noise angular rate sensor is characterized in that a laser light source is used to generate a compression light field, a coherent state light field and a local light field through a light path structure; after the compression light field and the coherent state light field are coupled to form a mixed light field, a Sagnac effect is generated in a corresponding light path structure, a light field carrying rotation speed and compression angle deviation information is formed, and the light field and a local light field jointly carry out balanced zero beat detection to obtain mixed information in an electric signal form; the mixed information outputs rotating speed information and a compression angle control signal through a compression angle matching system; wherein the compression angle control signal controls the compression angle of the compressed light. The compressed light field is injected into the vacuum end of the coupler of the fiber-optic gyroscope, the shot noise limit can be broken through, the performance of the fiber-optic gyroscope can be optimized, the compression angle can be matched with the working state of the fiber-optic gyroscope in real time through the compression angle adjusting system, the fiber-optic gyroscope outputs low-noise signals in real time during working, and the system is simple in structure and convenient to operate. The precision of the fiber-optic gyroscope is further improved.

The present application belongs to the field of quantum technology, and discloses a quantum illumination method based on a non-Gaussian two-mode entangled state in the field of quantum illumination, which comprises preparing a non-Gaussian two-mode entangled state, dividing it into two modes of light, one of which is signal mode light and the other is idle frequency mode light, emitting the signal mode light to the area of a potential target, directly emitting the idle frequency mode light to a measurement end, and finally measuring the reflected mode light of the potential target area and the idle frequency mode light at a receiver. The measurement scheme used in the present application uses double homodyne detection measurement. The present application has the following important advantages: 1. By improving the input state to a non-Gaussian two-mode entangled state, the value of quantum Fisher information can be effectively improved; 2. By using double homodyne detectors at the measurement end, the signal-to-noise ratio in the quantum illumination system can be effectively improved and error propagation can be reduced.

The application discloses a CVQKD system based on integrated microcavity optical frequency comb, which comprises a sending end, an interference end and a receiving end. The sending end generates optical frequency comb by using an integrated microcavity, modulates entangled photon pairs, sends part of signal light and idler light to the receiving end, performs homodyne detection on the other part of signal light and idler light, records the raw code value, performs classical communication with the receiving end, sends the encrypted message, and processes the key. The interference end generates interference to the communication. The receiving end generates optical frequency comb by using an integrated microcavity, modulates entangled photon pairs, receives the idler light and signal light from the sending end, performs homodyne detection, records the raw code value, performs classical communication with the sending end, decrypts the received message, and processes the key. The application further provides an optical path implementation method of the CVQKD system based on the integrated microcavity optical frequency comb. The application solves the problems of low entanglement degree, high complexity and high power consumption of the existing entangled state continuous variable quantum key distribution system.

Disclosed herein is a homodyne detector (200) comprising a first beam splitter (202) and a second beam splitter (204) optically coupled with each other via at least an optical modulator (210). The first beam splitter (202) is configured to receive an optical signal and a reference optical signal as input and generate a first optical beam and a second optical beam based on the optical signal and the reference optical signal. The second beam splitter (204) is configured to receive at least the first optical beam through the optical modulator (210). The homodyne detector (200) comprises a control circuit (212) coupled to an output end of an amplifier (110) of the homodyne detector (200) and the optical modulator (210). The control circuit (212) is configured to balance one or more imbalances in the homodyne detector (200) by controlling the first optical beam passing through the optical modulator (210) based on an output signal of the amplifier (110).