100 results about "Wavelength modulation" patented technology

The invention relates to the field of optical detection, in particular to a spectrum confocal displacement measuring system and method based on wavelength modulation, and the measuring system comprises a tunable laser, a dichroscope, a dispersion lens, a pinhole, a photodiode and a modulator. The tunable laser is used for outputting laser; the modulator is used for calculating a wavelength modulation function of the tunable laser according to a nonlinear relationship between the wavelength of the dispersion lens and the axial focusing position, and performing nonlinear modulation on the output wavelength of the tunable laser through the wavelength modulation function; the change rate of the output wavelength of the tunable laser adapts to the axial resolution of the dispersion lens; the dichroscope is used for reflecting and transmitting the light beam; the dispersion lens is used for dispersing the light beam and focusing the light beam to different positions of the sample; the photodiode is used for receiving each beam of reflected light reflected by the sample and converting an optical signal into an electric signal; the pinhole is used for suppressing defocused light. According to the invention, the measurement precision and the stability of measurement results can be improved.

The invention discloses a multi-gas synchronous detection device and method based on dual-frequency wavelength modulation and demodulation, and relates to the field of gas detection, the device comprises a light source module, a photoacoustic signal detection module and a data processing module; wherein the light source module outputs an excitation light beam and irradiates the excitation light beam into a gas chamber of the photoacoustic signal detection module; the excitation light beam is a light beam modulated by a sawtooth wave signal and two sine waves with different frequencies; the photoacoustic signal detection module receives photoacoustic signals generated after each gas to be detected in the gas chamber interacts with the excitation light beam and converts the photoacoustic signals into piezoelectric signals; and the data processing module performs secondary harmonic demodulation on the piezoelectric signal to obtain demodulated secondary harmonic data, and further inverts the concentration of the gas to be detected. According to the invention, two sine wave signals with different frequencies are superposed on the basis of a sawtooth wave signal, the frequency distribution of a modulation signal is expanded, and the concentration of gas adjacent to various absorption lines can be accurately detected at the same time.

The invention discloses a laser gas detection method and system for leakage inspection of a hydrogen-doped natural gas pipeline. Comprising a master control MCU, a signal generation module, a first laser driving temperature control module, a second laser driving temperature control module, a first semiconductor laser, a second semiconductor laser, a wavelength division multiplexer, a standard gas cell, a multi-reflection gas cell, a first photoelectric detection amplifier, a second photoelectric detection amplifier and a digital gas pressure intensity temperature sensor, the device comprises an orthogonal phase-locked amplification demodulation module, an OLED display screen, a vacuum pump, a drying tube, a handheld sampling tube and a porous gas diffusion probe. A laser absorption spectrum technology of time division multiplexing and wavelength modulation is adopted, and a specific implementation mode is that a semiconductor laser with narrow linewidth and adjustable wavelength is utilized, and non-interference accurate detection of methane and hydrogen in leakage inspection of the hydrogen-doped natural gas pipeline is realized through a high-precision time division multiplexing wavelength modulation spectrum absorption detection technology.

The invention discloses a saturated spectrum processing method for wide-range detection of an absorption spectrum of a tunable diode, and relates to the technical field of spectrum gas detection. According to the saturated spectrum processing method for wide-range detection of the absorption spectrum of the tunable diode, an effective spectrum signal is obtained by performing denoising and baseline correction on an original absorption spectrum signal, a plurality of spectrum characteristic parameters are extracted to calculate a saturated quantized value, and a complete absorption spectrum line contour is reconstructed by adopting a spectrum reconstruction algorithm according to the quantized value, so that the wide-range detection of the absorption spectrum of the tunable diode is realized. The method comprises the following steps of: constructing a saturation quantitative evaluation system, a layered self-adaptive spectrum reconstruction strategy, a dual-mode detection fusion mechanism and a working condition compensation model, calculating weights of an absorption spectrum and a wavelength modulation spectrum through an S-type function, correcting a preliminary concentration value by combining environment temperature, pressure and a compensation model, and outputting an accurate final gas concentration. Without additional hardware, wide-range high-precision gas detection is realized, and environmental interference and saturation influence are eliminated.

The invention belongs to the related technical field of sensors, and provides a multi-parameter integrated acquisition optical fiber sensor and a monitoring system thereof in order to solve the problem that high-precision monitoring of a static signal and a dynamic signal is difficult to consider by an existing sensor at the same time, a sensing cavity is sequentially divided into a static signal sensing area and a dynamic signal sensing area in the axial direction; the static signal sensing area adopts a multi-core fiber, fiber gratings are respectively engraved on the multi-core fiber, and the wavelength demodulation of the static signal is realized through the central wavelength drift distance of the fiber gratings; the dynamic signal sensing area is provided with a dynamic signal sensing unit, the dynamic signal sensing unit comprises F-P air microcavities formed between the dynamic signal sensing unit and the end faces of all fiber cores of the multi-core optical fiber, and intensity demodulation of dynamic signals is achieved through cavity length changes of the F-P air microcavities. According to the invention, a wavelength modulation and intensity modulation parallel composite demodulation mechanism is adopted, and decoupling acquisition of static strain, temperature and dynamic vibration is realized in a single sensor.

The invention discloses a temperature-pressure-resistant vibration methane carbon isotope detection system for oil and gas logging, which belongs to the technical field of oil and gas logging and comprises a gas sample pretreatment module, an optical sensing module, a driving and temperature control module and a core control and algorithm module. The core control module is realized by an FPGA (Field Programmable Gate Array) and is integrated with a self-adaptive multi-resolution scanning and compressed sensing reconstruction algorithm. The method comprises the following steps: performing current segmented scanning and wavelength modulation on the laser; light path anti-vibration coupling is realized through closed-loop control of the MEMS galvanometer; acquiring sparse sampling spectrum data; reconstructing a high-resolution spectrum by using compressed sensing; and inversing CH4 and CH4 concentrations by adopting Voigt linear fitting, and calculating a delta C value. The precision, the speed and the long-term stability of methane carbon isotope detection in a logging site temperature-pressure vibration coupling disturbance environment are remarkably improved.

The invention provides an unattended operation method and system based on the Internet of Things technology, and the method comprises the steps: carrying out the multi-band scanning of a target substance through a tunable laser spectrum device of a distributed laser detection node, generating an original spectrum signal, carrying out the dynamic wavelength modulation and adaptive noise filtering processing, and carrying out the detection of the original spectrum signal. And matching and outputting a preliminary recognition result in combination with the dangerous substance feature library. And performing confidence evaluation and correction on the result by using a local federal learning model, generating a parameter update quantity through correlation analysis, and uploading the parameter update quantity to a central server. And dynamically updating a local model and laser scanning parameters based on the issued federal global model parameter weight distribution, and realizing accurate identification of the dangerous substances. According to the invention, the accuracy of dangerous substance identification and the self-adaptive capability of the system are improved.

Provided are an electro-optical device, a laser device, and an electro-optical dual-comb generator. The electro-optical device includes a waveguide configured to generate a dispersive wave of which a center wavelength is different from a center wavelength of the incident wave of the waveguide, and a wavelength modulator disposed along the waveguide and configured to absorb the incident wave propagating through the waveguide, wherein, as the wavelength modulator absorbs the incident wave, the center wavelength of the dispersive wave changes.

The invention discloses a portable Raman spectrum measuring device for petroleum heavy metal ion detection, which belongs to the technical field of petroleum exploitation and processing, and comprises a light source module, a wavelength modulation module, an excitation light path module, a confocal detection module, an imaging module, a data processing module, an image processing module, an automatic focusing module and a portable shell, the fiber bragg grating can accurately adjust the excitation wavelength, and the influence of wavelength deviation on the detection precision is reduced; the contrast ratio and the sensitivity of Raman signals can be effectively improved through multi-wavelength excitation and differential signal processing and a displacement excitation Raman differential spectrum technology; the device provided by the invention can effectively improve the portability, accuracy and experimental efficiency of Raman spectrum detection, is suitable for crude oil pollution detection requirements in oil exploitation and processing processes, and has a wide application prospect.

The invention provides a photoacoustic gas measurement method and a photoacoustic gas measurement system based on a series sensibilization technology, and relates to the technical field of optical gas sensing. The first-stage light absorption enhancement structure is used for carrying out maximum photoacoustic conversion on target gas to generate an initial photoacoustic pressure signal, the second-stage acoustic resonance structure is introduced to carry out resonance amplification on sound waves with specific frequency, a tandem cascade sensibilization framework of light absorption enhancement and acoustic resonance amplification is constructed, and through mutual verification analysis, the sensitivity of the target gas is improved. Calculating coherence outside preset noise analysis frequency band data, identifying and inhibiting common-mode noise interference caused by environment vibration and the like, generating feedback control parameters while calculating final gas concentration, adaptively adjusting intensity modulation frequency and wavelength modulation depth, and realizing high-precision and high-precision measurement. The measurement reliability, the dynamic range and the adaptive capacity of the system under complex working conditions are improved, and multiplier-level breakthrough of the sensitivity of the system and collaborative optimization of the performance are achieved.

The invention discloses a wavelength modulation spectral signal denoising method based on an unsupervised auto-encoder. The method comprises the following steps: step 1, constructing a WMS harmonic signal data set; step 2, training an HA-CAE denoising network model; 3, the HA-CAE denoising network model is evaluated and optimized, and an optimal HA-CAE denoising network model is obtained; and step 4, integrating the optimal HA-CAE denoising network model to a sensor system to realize real-time denoising processing of the signal. According to the method, a targeted data set and an improved HA-CAE denoising network model are constructed, three attention mechanisms are fused to accurately capture signal local details, time sequence association and global channel characteristics, non-stationary mixed noise characteristics are adapted, the denoising effect is improved, the generalization ability and the real-time processing ability of the model are guaranteed, and the method is suitable for popularization and application. The method is suitable for wavelength modulation spectrum signal processing in various complex scenes such as industrial leakage monitoring and atmospheric environment detection.

The invention belongs to the technical field of intelligent optical fiber devices, and particularly relates to an optical fiber memristor of a minimum neural network, and the memristor comprises a probe optical module which emits low-power continuous probe light; the erasing pulse module emits multi-wavelength regulation and control pulse light, and the multi-wavelength regulation and control pulse light and the low-power continuous probe light are combined to form erasing pulse light; erasing pulse light is input into the two ends of the single-mode optical fiber memristor module respectively; the photoelectric detection module is coupled with the single-mode optical fiber memristor module and monitors the state and the output signal of the single-mode optical fiber memristor module in real time. According to the optical fiber memristor designed in the invention, a bidirectional pulse light regulation and control mode is utilized, so that non-volatile storage with higher storage capacity can be realized; the minimum neural network is constructed through an all-optical means, training and operation of optical multiplication can be achieved, and compared with a traditional electrical means, the operation speed is higher, and energy consumption is smaller.

The invention discloses a gas spectrum transparent transmission light path system for hydrogen and hydride, which relates to the technical field of spectral analysis and comprises a wide-spectrum light source module, a multi-pass optical path pool, a film lithium niobate modulation module, a two-dimensional material enhanced micro-ring resonant filter, a Fourier transform infrared spectrometer, a data processing terminal and a polarization controller. The wide-spectrum light source module is used for generating wide-spectrum light signals covering hydrogen and hydride characteristic absorption wavebands; according to the invention, the wide-spectrum light source module covers hydrogen and hydride characteristic absorption in different wavebands, simultaneous detection of multiple components is realized in combination with the wide tuning range of the two-dimensional material enhanced micro-ring resonant filter, wavelength modulation is carried out by utilizing the thin-film lithium niobate modulation module, adjacent absorption peaks are accurately distinguished in cooperation with the transmission bandwidth of the micro-ring filter, and the detection accuracy is improved. In addition, the action path is prolonged through the multi-pass optical path pool, and the detection sensitivity of weak absorption signals is enhanced in combination with pressure control and the corrosion-resistant gas chamber.

The invention discloses a mixed gas concentration prediction method and device based on wavelength modulation, and the method comprises the steps: setting the concentration ranges of two gases of a training set and a test set of a deep residual network model according to an absorption coefficient ratio, and carrying out the segmented matching and step size gradual change of a data set, thereby obtaining the training set and the test set; all second harmonic peak values in the concentration range are locked to the same value, normalization coefficients corresponding to all second harmonic signals are obtained, and then a normalized training set and a normalized test set are obtained; using the normalized training set to train a deep residual network model; the trained deep residual network model is tested through the normalized test set; the model can accurately predict any concentration, including two gases exceeding the concentration range of a training set. According to the wavelength modulation technology, the half-width of the second harmonic extracted by the lock-in amplifier is much narrower than the half-width of the absorption spectrum, so that the overlapping interference of multiple spectral lines of the mixed gas can be effectively avoided.

A method of identifying substances, such as atmospheric and greenhouse gases, comprises emitting modulated radiation of different wavelengths towards a target area, wherein the radiation is modulated using respective modulation codes for a predetermined number n of wavelength bands that correspond to a range across an absorption spectrum for the substance, and analyzing the spectrum of radiation from the target area to identify the gas in the target area. The spectrum is analyzed using a time correlation of the emitted modulated radiation and the detected radiation. The radiation is modulated using respective modulation codes for the different wavelengths, and the modulation codes may be modified by insertion of a gap between each bit of the modulation code, the gap having a duration of at least n-1 bits.

A method for auto-tuning an optical transponder that is coupled to an optical terminal comprises: cycling through wavelengths in sequence by, for each wavelength: modulating the wavelength to convey a wavelength identifier of the wavelength, to produce a modulated wavelength that conveys the wavelength identifier; transmitting the modulated wavelength from the optical terminal through an optical demultiplexer that is configured to pass wavelengths to output ports of the optical demultiplexer; waiting to detect a response wavelength, transmitted by the optical transponder, which matches the wavelength; and determining, based on whether the response wavelength is detected, whether to repeat cycling using a next wavelength because the optical transponder is not tuned or to stop cycling because the optical transponder is tuned.

The utility model discloses an overhead line system image acquisition device capable of resisting sunlight interference, which belongs to the technical field of railway overhead line system detection, and comprises a modulation laser light source for emitting a specific wavelength modulation light pulse of a non-sunlight main energy wave band, and cameras respectively arranged on two sides of the modulation laser light source, and a narrow-band optical filter which is matched with the modulation laser light source and can pass through optical signals with specific wavelengths is additionally arranged on the camera. A narrow-band optical filter is additionally arranged on a device (namely a camera) for acquiring an image, so that only an optical signal with a specific wavelength can enter the camera through the narrow-band optical filter, and the optical signal with the specific wavelength is an optical signal of a non-sunlight main energy wave band; therefore, based on the additional arrangement of the narrow-band optical filter, the image acquired by the camera can be prevented from being interfered by light in a strong sunlight environment.

According to an aspect there is provided an apparatus for Raman light detection, said apparatus comprising: an illumination unit, configured to provide a wavelength modulation for generating and outputting wavelength modulated laser light towards a sample for inducing generation of Raman scattered light from the sample; a wavelength filter for filtering the Raman scattered light; and a light detector, configured to receive the Raman scattered light filtered by the wavelength filter and to provide an instantaneous response signal dependent on an intensity of the received Raman scattered light.

The application discloses a wavelength modulation surface plasmon resonance imaging sensing method, which generates multiple groups of illumination spectra by controlling a light-emitting diode, processes the spectra into p-polarized light, excites a sensing chip to generate surface plasmon resonance through prism coupling, collects corresponding reflected light intensity images by using a CMOS camera, and reconstructs surface plasmon resonance reflection spectra of each pixel on the sensing chip by using a smooth constraint reconstruction algorithm according to intensity observation values of the pixel in all images and corresponding illumination spectrum data, so as to further extract a phase signal and generate a spatially resolved phase image. The phase signal and the imaging scheme realize high-sensitivity and high-throughput sensing performance. The method realizes low-cost, high-signal-to-noise ratio and high-throughput sensing imaging.

The application provides a single-photon multi-wavelength imaging system and method based on a physical driving model, and belongs to the technical field of single-pixel multi-wavelength imaging; the application solves the problems of being easily affected by noise and poor imaging quality of existing single-photon multi-wavelength imaging schemes in extreme environments; the application comprises a multi-wavelength modulation illumination module, a spatial modulation coding module and a detection imaging module; the multi-wavelength modulation illumination module uses signal light with different modulation repetition frequencies to illuminate a color target object and scatter the color target object to the spatial modulation coding module; the spatial modulation coding module spatially encodes the color target object and transmits the color target object to the detection imaging module; the detection imaging module captures the modulation signal light and transmits the modulation signal light to a computer; a physical driving model program is prewritten in the computer; the physical driving model comprises a measurement value denoising module and a physical driving image reconstruction module; and finally, a high-quality color target object reconstruction image is obtained; the application is applied to photon imaging.

The invention discloses a structure and a method for wavelength modulation longitudinal polarization confocal vortex generation and topological charge, and belongs to the technical field of scattered field regulation and control of a surface plasmon field, and the structure comprises a plurality of bowknot type slit element atoms which are etched on a substrate and have the same shape and size, and a circular grating, the bowknot type element atoms are uniformly arranged on the circular contour according to different rotation angles theta and share the same circle center with the circular grating. The structure constructed by the invention can realize generation, disappearance and topological charge of wavelength-controlled non-double-wave longitudinal polarization confocal vortex light spots, and can realize confocal of dual-wavelength longitudinal polarization hollow light spots. Based on the above properties, the device can be applied to a hybrid multi-wavelength far field system.

The application provides a measurement method for reconstructing time-varying absorption based on fixed-point wavelength modulation technology, which comprises the following steps: applying a high-frequency sinusoidal scanning signal to a laser, wherein the scanning frequency is f m ; the wave number response of the laser has a nonlinear relationship with the current, and the nonlinear fitting of discrete wave numbers obtains a continuously changing wave number function v(t); the Beer-Lambert law is used to express the absorption rate α v (t) of the laser by the absorption medium; the Fourier transform and the lock-in filtering extraction are performed on α v (t) to extract the harmonic waves of the absorption rate function with time; the wave number information of the dynamic harmonic waves at any time is supplemented by numerically solving the inverse function of the wave number function at the rising edge or the falling edge, so that the absorption rate at each time is reconstructed, and the calibration-free measurement is realized. The absorption rate reconstructed by the application has a higher signal-to-noise ratio and does not reduce the time resolution of the spectrum.

A first circuit sends electrical data. The electrical data is sent to a vertical-cavity surface-emitting laser (VCSEL). A wavelength of the VCSEL is modulated. The modulating includes emitting, by the VCSEL, a wavelength-modulated beam (WMB). The WMB is based on the electrical data that was sent. The modulating can be based on injecting current into the VCSEL. The modulating can be based on VCSEL chirp. The WMB is coupled optically to an optical medium. The optical medium comprises a waveguide or a fiberoptic cable. The coupling optically is accomplished using a grating coupler, a mirror, or an off-axis diffractive lens. The optical medium is further coupled to a wavelength-dependent optical element (WDOE). The WDOE decodes the WMB into the electrical data that was sent. The electrical data is delivered to a second circuit.

Provided are an electro-optical device, a laser device, and an electro-optical dual-comb generator. The electro-optical device includes a waveguide configured to generate a dispersive wave of which a center wavelength is different from a center wavelength of the incident wave of the waveguide, and a wavelength modulator disposed along the waveguide and configured to absorb the incident wave propagating through the waveguide, wherein, as the wavelength modulator absorbs the incident wave, the center wavelength of the dispersive wave changes.

The invention discloses an SAR (Synthetic Aperture Radar) signal acceleration processing method and device based on a photon planar waveguide chip, and belongs to the technical field of photoelectron technology and signal processing. The method comprises the following steps: generating a to-be-processed SAR echo signal by a signal generator, and modulating the to-be-processed SAR echo signal to coherent laser sources with different wavelengths through a plurality of intensity modulators to obtain a multi-wavelength modulation signal; combining the multi-wavelength modulation signals into a single-beam optical signal, and adjusting the polarization direction to obtain a polarization-optimized modulation optical signal; and the modulated optical signal is input into the photon planar waveguide chip, and the optical signal output by the photon planar waveguide chip is coupled to the detector array through the on-chip end face coupler array to complete conversion of the photoelectric signal. The acceleration chip is small in size and high in integration level, and the number of processing channels of the network can be greatly increased.

The present invention discloses a system and method for detecting the absolute linear density of a grating, belonging to the field of optical detection technology. By adding the functions of incident light wavelength modulation and wavelength monitoring, different diffraction angles at the same position of the grating are obtained by adjusting the wavelength of the incident light, thereby determining the absolute linear density at that position. Without changing the wavelength of the incident light, the relative detection accuracy of the LTP for the grating linear density is dN / N=5×10 ‑7 The present invention can achieve absolute detection of each position by only changing the wavelength of the incident light once, thus ensuring detection efficiency. After theoretical analysis and actual testing, the present invention has achieved an absolute detection accuracy of grating line density of dN / N=1×10 ‑6 .

The invention provides an image quality analysis method and device based on circular truncated cone geometric constraint and negative feedback regulation and control. The method comprises the steps that S1, the vertical axis chromatic aberration, the axial chromatic aberration and the wave chromatic aberration of a multi-conjugate catadioptric zoom system are acquired; s2, solving the wave aberration of the multi-conjugate catadioptric zoom system after wavelength modulation; s3, determining the position of a characteristic aberration node according to the wave aberration, and calculating the diameter of an RMS light spot near a central view field; and S4, carrying out negative feedback regulation and control on the node position of the characteristic aberration by using the geometric constraint of a circular truncated cone, taking the abbe number of the material as a variable in a vertical-axis chromatic aberration and axial chromatic aberration correction mode so as to inhibit the influence of chromatic aberration, and comprehensively analyzing the imaging quality of the multi-conjugate catadioptric zoom system. The image quality comprehensive analysis method is suitable for image quality comprehensive analysis of a multi-conjugate refraction and reflection type zoom system, and particularly has a wide application prospect in a refraction and reflection type zoom optical system which realizes a high-performance zoom function and relatively wide spectral imaging through a deformation device.

This invention provides a method for fast laser wavelength locking and power modulation based on feedforward compensation, relating to the technical field of laser wavelength modulation technology. The method includes: parallel monitoring of laser state information; generating a compensation signal based on the state information; fusing and allocating the compensation signal to obtain a composite control signal; and adjusting the laser wavelength based on the composite control signal. This invention solves the problem of low laser modulation accuracy, thereby improving laser modulation accuracy.