371 results about "Heterodyne" patented technology

The invention belongs to the technical field of industrial measurement, and discloses a pump machine metal shell size detection method based on image analysis, which comprises the following steps: synchronously acquiring image data of a pump machine metal shell in a visible light wave band and a near-infrared wave band; the contrast ratio of image data is optimized through a dynamic exposure control technology, and a high-dynamic-range multispectral image is obtained; three-dimensional geometric information of the pump machine metal shell is obtained, registration fusion is carried out on the three-dimensional geometric information and the high-dynamic-range multispectral image, a dense three-dimensional point cloud model with multispectral textures is constructed, and a multi-frequency heterodyne algorithm is adopted to process a high-reflection area in the dense three-dimensional point cloud model; the method comprises the following steps: collecting a multi-angle reflection image of a pump machine metal shell by rotating a linear polarizer, calculating a Stokes vector to extract a diffuse reflection component, carrying out diffuse reflection component constraint and brightness suppression on a high-reflection area based on a CIE-Lab color space, and outputting a dense three-dimensional point cloud model after texture enhancement; and the size detection precision of the pump machine metal shell is improved.

The invention relates to the technical field of laser ranging, in particular to a double-optical-comb hybrid ranging device which comprises a signal detection optical path system and a signal demodulation optical path system. Wherein the signal detection optical path system comprises a first optical frequency comb, a first optical isolator, a first optical collimator, a first beam splitter prism, a reference mirror, a Faraday rotator, a convergence mirror and a target reflector; the signal demodulation optical path system comprises a second optical frequency comb, a second optical isolator, a second optical collimator, a half-wave plate, a second beam splitter prism, a third beam splitter prism, a first polarization controller, a first photoelectric detector, a reflector, a polarization beam splitter prism, a second polarization controller and a second photoelectric detector. A third polarization controller; and a third photoelectric detector. According to the invention, three ranging technologies of asynchronous optical sampling ranging, multi-heterodyne interference ranging and synthetic wavelength ranging are fused, and the problem that a large ranging range and high ranging precision cannot be simultaneously considered in the ranging process is solved.

The invention relates to a multi-degree-of-freedom motion synchronous measurement system and method based on time-space domain information fusion, which utilize a heterodyne interference phenomenon generated by a double-frequency light source to realize accurate measurement of displacement and angle by analyzing phase change of an interference signal generated by interaction of a measurement grating and a reference grating. The system comprises a double-frequency light source, an optical element, a measuring grating, a reference grating and a photoelectric detector, and the photoelectric detector comprises an array detector and a common photoelectric detector and is used for receiving interference light signals of different diffraction orders. The processing device at least comprises an angle measuring module. The angle module is used for resolving by fusing phase spatial-temporal characteristics and light spot displacement of signals on the array detector; a displacement module can be further included, calculation is carried out through the phase change of heterodyne interference signals on the detector along with time, and finally synchronous measurement of six-degree-of-freedom motion parameters can be achieved. The system has the advantages of being accurate, compact in size, high in light source efficiency and the like, and is suitable for multiple fields of photoetching machine wafer table positioning, ultra-precision machine tool machining and the like.

The invention belongs to the technical field of computer vision and optical measurement, and discloses a three-dimensional reconstruction method and device based on multi-frequency fringe synchronous optimization and a medium, and the method comprises the following steps: based on a monocular structured light system, projecting a plurality of groups of sine fringe images with different frequencies to the surface of an object to be measured through a projector, and carrying out the stepping of a plurality of phases, acquiring a corresponding image sequence by using a camera; using a structured light phase shift method to obtain a relative phase value of a pixel point; obtaining an initial absolute phase value and modulation intensity based on a structured light phase shift method and a multi-frequency heterodyne method; and carrying out joint optimization on the absolute phase and modulation intensity parameters of the multi-frequency fringes through a Gaussian-Newton iteration method. According to the method, the anti-noise capability and the reconstruction precision are improved, a parameter adjustment and threshold recovery mechanism is introduced in the optimization process, the convergence stability and abnormal value elimination are ensured, and the method is suitable for high-precision structured light application scenes such as industrial vision measurement and complex surface detection.

The invention provides a non-power-cut test method for mutual inductance parameters of a power transmission line under excitation of different-frequency signals and a related device, and solves the problems of difficulty in accompanying stop and high safety risk of adjacent lines. The method comprises the following steps: selecting one circuit in the same corridor for power failure, connecting the head end with an induced electricity suppression device, and performing three-phase short-circuit grounding at the tail end; injecting a different-frequency sinusoidal current of 45-55Hz into the power failure line; the synchronous measurement device collects head and tail voltage and current of a running line based on a satellite synchronous clock; extracting pilot frequency signals through two-stage notch filtering and Fourier transform; and different-frequency zero-sequence self-impedance and mutual impedance are calculated and converted into power-frequency impedance. According to the invention, accurate test without power failure can be realized, and safety and power supply reliability are guaranteed.

The invention discloses a cultural relic restoration decision-making method and system based on computer three-dimensional modeling, and relates to the technical field of cultural relic restoration, and the method comprises the following steps: building a unified time baseline, generating a phase reference field, introducing a double-frequency comb interference structure to reconstruct a humidity refraction field, locking a zero-phase anchor point, and forming an initial constraint condition of a scanning path; under an initial constraint condition, an airflow phase gradient is obtained by adopting a Schlenn pilot frequency chromatography method, a nonlinear diffraction nucleus is calculated, and a refraction residual spectrum is output for modeling correction. According to the method, humidity disturbance is recognized through interference measurement and chromatography, real-time compensation is achieved in combination with phase sheath and humidity control, the crack and material characteristics are fused through neural field modeling, the solidification process is played back in combination with a mineralization mechanism, and the three-dimensional modeling precision and the restoration decision scientificity are improved.

A high-resolution phase detection method and system based on a plane grating laser interferometer. The method uses a dual-frequency interferometer to measure the displacement, and the measurement signal processing comprises an integral part and a decimal portion, a phase equation set of a displacement measurement signal is constructed according to a measurement optical path principle of a heterodyne plane grating laser interferometer; a non-linear equation set for which the unknowns are instantaneous phase, interval phase and signal amplitude is established; and the equation sets above are solved by using the least squares method, so as to realize phase discrimination, thereby realizing precise displacement measurement. The method can solve the problems in the traditional time measurement-based phase detection technology, such as low measurement accuracy, and failing to satisfy small measuring range measurement. The measurement method can be applied to systems such as precision manufacturing equipment and lithography machine.

The invention relates to the technical field of optical imaging, and discloses a single-pixel color imaging system based on multi-wavelength radio frequency marking. The system comprises a light source module used for generating three laser beams with three optical primary colors; the radio frequency driving module is used for generating a radio frequency complex frequency signal; the light path adjusting module is used for performing heterodyne interference processing on the three laser beams according to the radio frequency complex frequency signal, respectively forming a light spot array and a reference light source and then combining the beams, and generating a combined beam to be incident on a measured target; each laser beam corresponds to one group of sub light spot arrays; sub light spot arrays with aligned spatial positions exist among the three groups of sub light spot arrays; the detected target detection module is used for collecting light data generated after a detected target reflects the combined light beam; and the image inversion module is used for performing image inversion processing on the optical data to generate a true color image of the measured target. According to the system, the light spot array of multi-wavelength laser incidence can be registered in the spatial position.

A zero-optical-path-difference double-frequency heterodyne grating ruler comprises a light source, a signal detecting and processing system, a polarization splitting prism, a first quarter-wave plate, a rectangular prism, a second quarter-wave plate, a third quarter-wave plate, a total reflection mirror, a long-strip prism, a reference grating and a 45-degree-placed polaroid. The two measuring light paths of the system always keep zero optical path difference, so that the measuring precision can be ensured, and the environmental stability of the system is also remarkably improved. And a high-precision and high-robustness measurement scheme is provided for precision equipment such as a photoetching machine and a precision motion platform.

The invention discloses an uninterrupted calibration method and device for a medium and low voltage current transformer and a medium. The method comprises the following steps: measuring a primary side original current signal of a to-be-measured current transformer by using a pre-prepared mobile calibration platform; injecting a reverse current with the same frequency as the injection current source of the current transformer to be detected into the current transformer to be detected, and counteracting a primary side original current signal of the current transformer to be detected; generating a pilot frequency current according to a pre-selected pilot frequency signal by using an injection current source, inputting the pilot frequency current to a primary side of the current transformer to be detected for pilot frequency current calibration, and collecting a secondary side output signal; performing error analysis on the to-be-detected current transformer based on the secondary side output signal, and determining an error analysis result; and adjusting the calibration parameters of the to-be-detected current transformer based on the error analysis result to perform pilot frequency current calibration again until the error analysis result meets a preset requirement, and completing calibration of the to-be-detected current transformer.

The invention discloses a planetary atmospheric trace gas spectrum telemetering and in-situ fusion detection system and method, and belongs to the technical field of deep space exploration. The detection system has a telemetering mode and an in-situ detection mode, and comprises a telescope module, a laser light source module, a heterodyne spectrum telemetering module, an in-situ absorption spectrum module, a gas sampling and enriching module and a signal acquisition, processing and control module. In the on-orbit stage, a heterodyne spectrum telemetering module is adopted, and a laser light source and sunlight signals are subjected to frequency mixing for atmospheric component telemetering; and after the detector enters an atmospheric descending section, the in-situ absorption spectrum module performs in-situ absorption spectrum measurement by utilizing the detection light of the same laser light source. By performing space-time fusion and joint inversion on the data acquired in the two modes, coherent detection from large-range general survey to fixed-point detailed survey is realized, the problems of load separation of telemetering and in-situ detection and difficulty in data fusion are solved, and the detection efficiency, the data consistency and the integration level of the system are greatly improved.

The invention discloses an SERF atomic gyro signal detection device and method based on an optical heterodyne method, and belongs to the technical field of atomic polarization stability control, after magnetic fields with x-axis frequency and y-axis frequency are applied to atoms in a sensitive unit air chamber, x-axis electron polarizability information under respective modulation frequencies comprises longitudinal polarizability information and longitudinal magnetic field information, and x-axis electron polarizability information and y-axis electron polarizability information under respective modulation frequencies comprise longitudinal polarizability information and longitudinal magnetic field information; the value of the longitudinal polarizability is obtained by resolving information contained in the two, and effective longitudinal polarizability closed-loop control is achieved through a liquid crystal phase delayer power stabilizing rate system. Based on the biaxial magnetic field modulation technology, interference of longitudinal magnetic field fluctuation on polarizability closed-loop control is effectively avoided, and effective polarizability in-situ closed-loop control is achieved.

The invention discloses a narrow linewidth laser frequency control device and method based on optical feedback discretization, and belongs to the technical field of laser control. In order to solve the problems of poor frequency stability and tuning range of an existing laser, a laser beam emitted by the laser is incident to an optical feedback assembly to generate front-cavity mirror transmission light; the optical heterodyne feedback adjusting assembly demodulates an electric signal corresponding to the transmission light of the cavity front mirror to obtain an error signal, and transmits the error signal to the high-voltage amplification control module end to control the PZT, so that the high-voltage amplification control module end controls the PZT according to the error signal to lock the laser frequency on the cavity mode frequency; and meanwhile, the laser controller changes the working current of the laser, so that the laser frequency is locked on each intrinsic cavity mode frequency of the optical resonant cavity, and a series of discrete wide-range stable locking frequencies are obtained under the control of the temperature control module.

The invention discloses a distributed optical fiber two-dimensional vector sensing system and method, the system uses an acousto-optic modulator group and an optical circulator group to ask a plurality of fiber cores of a multi-core optical fiber in parallel, heterodyne coherent detection uses local oscillator light to improve the signal-to-noise ratio, and through the relation between the fiber core position difference and the direction angle of a two-dimensional sound wave in the aspect of algorithm, the two-dimensional sound wave direction angle is obtained. According to the space division multiplexing distributed optical fiber acoustic sensing system, a two-dimensional vector signal is accurately restored, the measurement vector angle range of the space division multiplexing distributed optical fiber acoustic sensing system for two-dimensional sound waves is 0-360 degrees, the vector sensing range is larger than 50 km and far exceeds that of an existing system, and the detection capacity of the distributed optical fiber acoustic sensing system is greatly improved.

The invention relates to a Rydberg atomic communication receiving system and method based on AT split peak value analysis, and belongs to the technical field of quantum communication. The system comprises a detection laser, a coupling laser, an AOM / EOM, a function generator, a high-frequency signal generator, a cesium atom gas chamber, a photoelectric detector, a lock-in amplifier, a data acquisition module and a microwave signal output module. The AOM / EOM modulates the frequency of the detection laser; the microwave signal output module generates an AM modulation microwave signal and transmits the AM modulation microwave signal to the cesium atom gas chamber, so that the target Rydberg state atoms generate an AT splitting effect to calibrate system parameters; the photoelectric detector and the lock-in amplifier obtain a first harmonic component based on the transmission light. During communication, the system is arranged in a microwave electric field received by communication, and the data acquisition and processing module outputs AM modulation microwave signals received by the recovered cesium atom gas chamber based on calibrated system parameters and phase locking. The method solves the problem of signal distortion existing in EIT-AT direct communication transmission and the problem of tedious operation of a heterodyne method.

The invention discloses a surface topography detection method and system based on double optical comb surface domain frequency sweeping, and relates to the technical field of surface topography detection. According to the method and the device, the frequency sweeping function of the double optical combs is realized by utilizing the area domain frequency sweeping, so that the double optical comb light source capable of realizing high-precision distance measurement can be applied to an interference light path to realize area array distance measurement. Therefore, double-optical-comb frequency sweeping is used for replacing traditional light source frequency sweeping, double-optical-comb multi-heterodyne interference is combined with surface domain frequency sweeping, the measurement precision of the longitudinal depth is greatly improved, then the precision of three-dimensional reconstruction based on the longitudinal depth is improved, the ultra-high resolution ratio which breaks through the micron level and reaches the sub-nanometer level is achieved, and actually, the measurement precision of the longitudinal depth is improved. The atomic-scale surface topography detection with the longitudinal resolution being less than or equal to 0.1 nm can be realized.

The invention belongs to the field of wave energy power generation, and discloses a pilot-frequency floater wave energy device array structure optimization method, which comprises the following steps of: giving an input wave energy spectrum frequency band reconstruction division strategy by combining the technical attributes of a wave energy device; based on an energy obtaining spectrum theory, deducing full-band equivalent energy capture of the device, and clarifying energy obtaining contribution of the device in the array in each band; the input sea wave spectrum is used as the target spectrum, array configuration design is carried out, the matching condition of floaters in the array is determined, the accurate matching of the output level of the array and resources is realized, and the development and utilization efficiency of the array is improved. According to the method, factors such as the mass, the resonance bandwidth, the inherent frequency and applied PTO damping of the floater are comprehensively considered, the relation of influence factors is established, pilot frequency floater wave energy devices meeting the requirements under specific sea area conditions are efficiently found in a simple and rapid means, an array composed of the pilot frequency floater wave energy devices can absorb incident wave energy in a full-band mode, and the wave energy efficiency is improved. And the utilization rate of the wave energy is greatly improved.

The invention relates to a fringe projection high-reflection surface phase unwrapping method based on frequency reuse. The fringe projection high-reflection surface phase unwrapping method comprises the steps of collecting a multi-frequency fringe image and dividing the multi-frequency fringe image into an overexposure area and a non-overexposure area, solving a wrapped phase in the non-overexposure area by adopting a generalized phase shift method, obtaining an initial unwrapping phase based on a multi-frequency heterodyne algorithm, and performing block filtering and interpolation processing to obtain a fringe projection high-reflection surface phase unwrapping phase. A continuous unwrapped phase containing a high-reflection area is obtained, a complementary Gray code consistent with a wrapped phase period is constructed in combination with a multi-threshold constraint and is used for correcting the stripe level of an overexposure area, brightness attenuation design is further carried out on low and medium frequency stripes, frequency reuse is achieved, and the high-reflection area is obtained. Obtaining an unwrapped phase of an overexposure point in a non-high-frequency stripe and mapping the unwrapped phase to a high frequency; the method comprises the following steps of: extracting and fusing a wrapped phase by adopting one-dimensional Fourier and Hilbert transform for areas with overexposure of each frequency, and selecting and inhibiting spectrum leakage through a complete period, so that effective correction of the wrapped phase and stripe level of an overexposure point is realized, and a reliable unwrapped phase is obtained.

The invention discloses a laser Doppler heterodyne noninvasive blood glucose concentration measuring device and method, and belongs to the technical field of medical detection. Comprising a laser generating module which comprises a laser, and a first 1 / 2 wave plate and a polarization splitting prism which are sequentially connected with the laser; and the interference light path module is connected to the two sides of the polarization splitting prism respectively and comprises a first optical fiber coupler connected with the polarization splitting prism, and a second 1 / 2 wave plate and a second optical fiber coupler which are sequentially connected with the other side of the polarization splitting prism. The device has the advantages that noninvasive detection can be achieved, blood sampling wounds are avoided, and the comfort level of a patient is improved; the measurement precision is high, and the blood glucose value can be quickly and accurately obtained by using heterodyne interference and frequency shift technologies.

In a general aspect, a magnetic resonance system performs magnetic resonance measurements. In some examples, a magnetic resonance system includes a data processing device and a superheterodyne spectrometer system. The data processing device generates digital intermediate frequency (IF) signal information based on the pulse profile. The digital IF signal information is configured to suppress a mirror sideband in the magnetic resonance control signal. The superheterodyne spectrometer generates a magnetic resonance control signal based on the digital IF signal information.

The invention provides a double-circuit line mutual inductance online monitoring system based on a distributed sensor. The system comprises a distributed intelligent sensing node cluster module, a data processing module, an energy and communication module, a dynamic pilot frequency excitation control module and a mutual inductance parameter monitoring module. The distributed intelligent sensing node cluster module deploys one intelligent sensing node every 500 meters along the double-circuit line and is used for collecting mechanical data, environmental data and pilot frequency excitation response data of the double-circuit line in real time; the data processing module is used for receiving the original data transmitted by the distributed intelligent sensing node cluster module and preprocessing the original data; the energy and communication module is used for providing a power supply and a data transmission channel for each module; the dynamic pilot frequency excitation control module is used for dynamically adjusting a pilot frequency excitation signal according to the power frequency interference intensity; and the mutual inductance parameter monitoring module is used for constructing a line electromagnetic-mechanical coupling simulation model and calculating mutual inductance parameters of the double-circuit line.

Disclosed is a structured light three-dimensional measurement method based on joint multi-frequency heterodyne and time-gated overlapping coding strategy. Specifically, fringe images modulated by a target surface are firstly collected and processed to obtain corresponding wrapped phase maps according to the phase-shifting method. Then, the wrapped phase maps are re-organized following the time-gated overlapping coding strategy, and further proceeded to obtain corresponding multi-frequency heterodyne unwrapped phase maps. With the unwrapped phase maps, a corresponding three-dimensional point cloud can be derived with the calibration parameters. The present application uses multi-frequency heterodyne method for phase unwrapping, promising high stability of phase-unwrapping and high measurement accuracy. Furthermore, the temporal correlation among the fringe images is fully exploited by the proposed time-gated overlapping coding strategy to further improve the measurement accuracy. Besides, only a few sinusoidal fringe images need to be used to complete one single measurement, highly promoting the measuring speed.

The invention discloses a device for generating Mach-Zehnder interference, a photo-thermal spectrum gas sensing device based on the device and a detection method, and belongs to the technical field of laser spectrum gas sensing. The interference device sequentially comprises an optical frequency comb and a first light beam splitter on a light transmission path; a movable arm reflector group is arranged on the light path of one light beam B in the two light beams split by the first light beam splitter, the path of the light beam B is changed through the movable arm reflector group, the light beam B intersects with the light path of the other light beam C, and a beam combiner is arranged at the intersection; the movable arm reflector group is connected with a driving mechanism, the driving mechanism is used for driving the movable arm reflector group to do linear motion, and the track of the linear motion is parallel to the straight line where the light beam B is located. The interference device does not need to use a local oscillator optical comb and a signal optical comb to carry out multi-heterodyne interference, can directly use the moving speed of a movable arm reflector group in a Mach-Zehnder interference structure to calculate a down-conversion factor, and maps each longitudinal mode of the signal optical comb in an optical frequency to a radio frequency component one by one.

A method and apparatus for an angle meter cooperatively using two or more non-contact distance meters for measuring distances to a surface along substantially parallel lines. The measured distances are used for estimating or calculating the angle to the surface and the distance to the surface. The distance meters may use optical means, where a visible or non-visible light or laser beam is emitted and received, acoustical means, where an audible or ultrasound sound is emitted and received, or an electro-magnetic scheme, where radar beam is transmitted and received. The distances may be estimated using a Time-of-Flight (TOF), homodyne or heterodyne phase detection schemes. The distance meters may share the same correlator, signal conditioning circuits, or the same sensor. Two or more angle meters may be used defining parallel or perpendicular measurement planes, for measuring angles between surfaces, and for estimating physical dimensions such as length, area or volume.

The invention discloses a distributed sound wave sensing device based on PDH frequency locking and a demodulation method. The distributed sound wave sensing device comprises a narrow linewidth laser, a first optical fiber coupler, a heterodyne phase sensitive optical time domain reflectometer and a frequency stabilization feedback module. The frequency stabilization feedback module comprises a frequency stabilization modulation and demodulation module, a reference cavity and a server; the frequency stabilization modulation and demodulation module comprises an electro-optical modulator or an acousto-optical modulator, a photoelectric detector, a multiplier and a low-pass filter; the first path of light enters a reference cavity for resonance after being modulated by an electro-optical modulator or an acousto-optical modulator, a resonance signal enters a photoelectric detector through cavity reflection, and a signal output by the photoelectric detector is subjected to signal demodulation by a multiplier and a low-pass filter and then is used as feedback to be input into a server for proportional-integral processing; the laser is fed back and output to a modulation interface of the narrow-linewidth laser, and frequency compensation is performed on the laser, so that the laser is locked on the reference cavity; according to the invention, through frequency stabilization and homologous modulation and demodulation, line width and phase drift of the laser can be suppressed at the same time.

The invention discloses a color Gray code coding auxiliary phase unwrapping method and an applied three-dimensional imaging method and system, and belongs to the technical field of three-dimensional imaging. The method comprises the following steps: constructing two groups of colored sine stripe patterns with different frequencies, projecting a scene to be detected, and capturing the two groups of stripe patterns; converting the stripe pattern from an RGB format into an HSV format, extracting a hue channel and performing Gray code decoding; extracting a hue channel from the RGB-format fringes to perform intensity normalization processing, then filling the hue channel into a single-channel image, calculating a wrapped phase by using a phase shift formula, then calculating heterodyne phases of fringe patterns with different frequencies through a multi-frequency heterodyne method, and performing first unwrapping on the wrapped phase; and unfolding the phase diagram which is unfolded for the first time in an auxiliary manner by utilizing a Gray code decoding order, thereby obtaining a final absolute phase. Gray codes are coded and embedded into different channels of two groups of patterns, so that the number of required patterns is remarkably reduced, and the measurement efficiency is effectively improved.

The invention provides a system and a method for measuring insertion loss and return loss of a multi-core optical fiber link based on an OFDR (Optical Frequency Domain Reflectometer), and belongs to the field of optical fiber link diagnosis and measurement. The system is composed of a multi-wavelength laser, three wavelength division multiplexers, two couplers, N circulators, a photoelectric detector, a data acquisition card, a to-be-measured link and an upper computer, the multi-wavelength laser outputs laser with N wavelengths, the wavelength division multiplexers multiplex signals and then divide the signals into signal light and reference light through a first coupler, the signal light is used for being output to the to-be-measured link, and the reference light is used for being output to the to-be-measured link. A mixing signal formed by the reflected light of the to-be-measured link and the reference light interferes in the photoelectric detector, a coherent mixing signal containing the insertion loss and return loss information of the to-be-measured link is measured, and the insertion loss and return loss of each node of the to-be-measured link can be calculated by analyzing the coherent mixing signal. By using the OFDR technology, the full-range measurement from the starting point to the ending point of the optical fiber is realized, so that the OFDR can comprehensively diagnose the health state of the optical fiber link.

The invention discloses a multidimensional communication sensing system integrating an optical transmission network and BOTDR / DAS distributed sensing, and relates to the technical field of optical fiber communication and optical fiber sensing. The system comprises an OTN transmission subsystem, an optical fiber link and a BOTDR / DAS fusion sensing subsystem. Wherein the OTN transmission subsystem is used for realizing high-capacity data transmission through an optical fiber link; and the BOTDR / DAS fusion sensing subsystem is used for realizing strain, temperature and vibration distributed measurement of an optical fiber link through a Brillouin scattering and Rayleigh backscattering mechanism. According to the system, a double-self-heterodyne demodulation architecture and a reverse wavelength division multiplexing mechanism are adopted, cooperative demodulation and high-isolation transmission of BOTDR and DAS signals are achieved under the common-fiber condition, and high-speed communication and distributed temperature, strain and vibration synchronous monitoring within the 100 km range can be achieved. According to the method, a technical foundation can be laid for realizing physical layer intelligentization of the in-service power OTN.

The invention relates to the technical field of space photoelectric detection, in particular to a digital weak light phase-locked control system and method based on phase readout, and the system comprises a laser interference and photoelectric conversion structure, a phase tracking readout module and a weak light phase-locked control module which are connected with one another. The laser interference and photoelectric conversion structure is used for generating a laser heterodyne interference signal based on the local laser and the weak laser, converting the laser heterodyne interference signal into an electric signal and inputting the electric signal to the phase tracking reading module; the phase tracking read-out module is used for tracking the phase of the laser heterodyne interference signal through the electric signal, calculating phase error information and inputting the phase error information to the weak light phase-locked control module; and the weak light phase lock control module is used for controlling the frequency of the local laser based on the phase error information and locking the local laser to the phase of the weak light laser. According to the invention, rapid, high-precision and long-time automatic phase locking under the extremely weak light condition is realized.

The invention relates to a reduced-size FMCW lidar imager system. The imager system comprises an optical source 10 for a coherent, continuous and frequency-modulated primary signal Sp in order to illuminate the scene 2; an optical collection element 41 configured to collect a backscattered signal Sret,c; a photodetector 50 intended to receive a heterodyne signal Sh associated with the collected signal Sret,c; and a processing unit 60 configured to determine the distance zsc from the scene based on a beat frequency of the heterodyne signal sh. It is configured to fully direct the primary signal Sp to the scene 2. It additionally comprises a reflector 42 configured to reflect a portion Spr,nc, called uncollected signal Sret,nc, of the backscattered signal Sret, not collected by the optical collection element 41, in the direction of the scene 2.