7 results about "Homodyne detection" patented technology

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.

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 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 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 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 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 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.