39 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.

The present disclosure belongs to the field of photoacoustic signal detection, and specifically relates to a quantum-enhanced all-optical photoacoustic signal detection device and method. The problem of low sensitivity of photoacoustic signals based on interference measurement is solved, and high-sensitivity detection of photoacoustic signals generated by living organisms including human bodies can be achieved. A degenerate optical parametric oscillator based on a first-type phase matching crystals is used for preparing a vacuum squeezed state light field, a coherent control technology is used for locking the squeezed angle to obtain the quadrature phase vacuum squeezed state, the prepared quadrature phase vacuum squeezed state light field is injected into the vacuum channel of a Michelson interferometer, and a balanced homodyne detection mode is used for achieving detection of the quantum-enhanced photoacoustic signals.

A system and method are provided for entanglement assisted quantum sensing. An entangled source generates entangle photon pairs that include a signal photon and an idler photon. The signal photon is modulated and transmitted to a target. In the monostatic configuration, the idler photon stays at the radar, where the idler photon passes through a quantum memory or delay line and an optical phase-conjugate module. The radar return signal includes signal photons that have interacted with the target (e.g., reflected from the target). The received signal photons are detected using balanced homodyne detection by beating the received signal photons against the phase-conjugate idler photons, which function as a local oscillator. The target is detected using a cross-correlation between the electrical signal from the homodyne balanced detector and the modulation pattern used to modulate the signal photons.

A planar optical waveguide device which has improved resistance to optical loss and improved stability of the entire system of balanced homodyne detection is realized. An embodiment is an optical waveguide device for measurement of squeezed light using balanced homodyne detection, including an amplifier circuit that is connected to a signal light input port for inputting the squeezed light and performs phase-sensitive amplification, and a multiplexing / demultiplexing circuit that is connected to a local oscillator optical input port and an output of the amplifier circuit, has local oscillator light and the amplified squeezed light incident on the circuit, and outputs the light interfering with each other to two output ports.

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 invention discloses a measurement method and system for quantum weak signal detection, and relates to the quantum precision measurement and quantum topology technology, and the method comprises the steps: constructing a dual-mode non-reciprocal SSH lattice model based on a waveguide; measuring an extremely weak optical signal at the position of a cell m, coupling the cell m with an optical fiber, driving laser to enter and couple to a waveguide SSH lattice through the optical fiber, and measuring a reflected signal at a port of the optical fiber; adjusting the specifications of the waveguide units to optimize coupling strength parameters among the waveguide units so as to obtain detection signals with increased single photon signal-to-noise ratio indexes; and at a specified moment, starting the driving laser, and adjusting the phase of the driving laser and the homodyne detection phase to measure the signal-to-noise ratio of the single photon. The invention provides a system scheme for improving the detection sensitivity of local weak signals in an exponential level.

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.

A method of linearizing an output of an interferometer includes: obtaining an optical signal from a laser at an input of the interferometer; converting, with a first photodiode connected to an optical through-port of the interferometer and a second photodiode connected to an optical cross-port of the interferometer, a detected optical intensity of the optical signal at the optical through-port and the optical cross-port into two photocurrents using self-homodyne detection; providing the two photocurrents to a logarithmic ratio amplifier to determine a logarithmic ratio of the two photocurrents; processing the logarithmic ratio by scaling the logarithmic ratio and introducing a DC output offset voltage to provide an output voltage; and compensating for the DC output offset voltage using a differential buffer amplifier connected to the output of the logarithmic ratio amplifier to provide a DC output voltage that corresponds to a linearized output of the interferometer.

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 present invention provides a self-balanced quantum random number generator based on vacuum fluctuation measurement and a usage method, comprising: a laser, a vacuum state generator, a homodyne detection module, a weak signal amplifier, an analog-to-digital converter, an entropy evaluation module, and a post-processing module; the homodyne detection module includes a beam splitter, a photodetector, an adjustable optical attenuator, and a subtractor; the output end of the laser is connected to one input end of the beam splitter; the output end of the vacuum state generator is connected to the other input end of the beam splitter; the output end of the beam splitter is connected to the input end of the adjustable optical attenuator; the output end of the adjustable optical attenuator is connected to the input end of the photodetector; the output end of the photodetector is connected to the subtractor; the weak signal amplifier, the analog-to-digital converter, the entropy evaluation module, and the post-processing module are connected in sequence; the input end of the weak signal amplifier is connected to the output end of the subtractor. The present invention can obtain quantum random numbers with higher randomness and effectively remove the DC bias in the random numbers.

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.

The present disclosure relates to a system and method for performing Gaussian boson sampling by time-multiple 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 pulse pairs of squeezed vacuum states, performing time-multiple correlation of a plurality of such pairs of squeezed vacuum states, measuring states from the generated pairs of squeezed vacuum states by homodyne detection, feeding forward the homodyne results of the measured states to a displacement unit, performing a displacement operation on remaining states from the generated pairs of squeezed vacuum states, and counting the states output from the displacement unit.

To contribute to reducing the amount of calculation required for fitting processing performed on an interference signal of signal light and reference light in optical communication.SOLUTION: A relative phase difference compensation device according to the present disclosure separates signal light and reference light from an optical signal, generates inverse function data indicating the inverse function of a specific function indicated by an interference output signal generated by homodyne detection to modulate the separated reference light, combines the separated signal light and modulated reference light, separates a polarization component of the signal light and a polarization component of the reference light from the combined signal light and reference light, performs homodyne detection on the separated polarization component of the signal light and the polarization component of the reference light to generate an interference output signal, estimates the relative phase difference between the signal light and the reference light based on the generated interference output signal, and generates offset value data that cancels out the relative phase difference between the signal light and the reference light based on the estimated relative phase difference between the signal light and the reference light.SELECTED DRAWING: Figure 4

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 invention discloses a high-Q-value light force sensing device based on a silicon nitride film, and belongs to the technical field of quantum sensing and quantum optics. The low-noise coherent light system outputs probe light and Local light; probe light is injected into the pressure sensor system; the pressure sensing system is positioned in the vacuum system; the pressure sensing system extracts probe light of the modulation signal with the fixed frequency and injects the probe light into the balance zero beat detection system, Local light is also injected into the balance zero beat detection system, and the modulation signal with the fixed frequency is read; the balance zero beat detection system is electrically connected to the high-precision auxiliary locking loop system; then connecting to a Local light phase controller to adjust the phase of the Local light; the balance zero beat detection system is electrically connected to the quality factor evaluation system; according to the invention, under the condition of ensuring a relatively high quality factor, the characteristic of small cavity volume is still ensured, and the cavity length of the film cavity is adjustable, so that a light field can be effectively enhanced, and improvement of the sensitivity of light force sensing is facilitated.

The invention discloses a vacuum-state quantum random entropy source chip and a random number sequence generation method, and belongs to the technical field of vacuum-state quantum random entropy sources and quantum integrated chips. A monolithic integrated chip of a light source, a beam splitter module and a balanced homodyne detection module is designed, the beam splitter module is formed by connecting multiple stages of beam riffles in series, each beam riffle comprises a first port, a second port and two output ends, the first port of the first-stage beam riffle receives local oscillator laser emitted by the light source, and the second port of the second-stage beam riffle receives local oscillator laser emitted by the balanced homodyne detection module. The second port of each level of light beam riffle inputs a vacuum state, and split laser carrying a vacuum state signal output by the output end of each light beam riffle is used as an input signal of the first port of the next level of light beam riffle; in use, the multi-channel quantum random number sequence can be generated by starting the light source. The system can meet the application requirements of small size, low cost, stable performance and high reliability, has the advantages of high confidentiality, high speed, multiple channels, high integration and the like, and can meet more application scenes.

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.

An analog-digital conversion method according to the present invention is a method for converting an optical analog signal into an electrical digital signal, the method including: performing at least one of affine transformation with first reference light and homodyne detection with a detection axis of second reference light on the optical analog signal; converting the optical analog signal subject to transformation or detection into an electrical analog signal by photoelectric conversion; and converting the electrical analog signal into an electrical digital signal by thresholding.

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.

A high-efficiency information extraction method and measurement system based on Rydberg atom low-frequency detection. This extraction method is based on the avoidance of background noise by coherent detection technology, uses Rydberg atoms to convert the modulation of low-frequency electromagnetic fields into quantum coherent phase changes, and adopts homodyne detection and heterodyne detection to accurately extract the amplitude and phase information of the low-frequency electromagnetic field, significantly improving the measurement sensitivity of weak low-frequency electromagnetic fields.

A system and method are provided for entanglement assisted quantum sensing. An entangled source generates entangle photon pairs that include a signal photon and an idler photon. The signal photon is modulated and transmitted to a target. In the monostatic configuration, the idler photon stays at the radar, where the idler photon passes through a quantum memory or delay line and an optical phase-conjugate module. The radar return signal includes signal photons that have interacted with the target (e.g., reflected from the target). The received signal photons are detected using balanced homodyne detection by beating the received signal photons against the phase-conjugate idler photons, which function as a local oscillator. The target is detected using a cross-correlation between the electrical signal from the homodyne balanced detector and the modulation pattern used to modulate the signal photons.

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.