51 results about "Wavelength modulation" patented 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 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.

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 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.

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.

The present invention provides a pulsed light generation apparatus and a pulsed light generation method capable of generating amplified pulsed light over a wide wavelength range. [Solution] The pulsed light generation device 1A comprises an oscillator (oscillator) 2 that oscillates pulsed light as seed light L0, a fiber amplifier (broadbanding unit) 3 that broadens the spectrum of the seed light L0 oscillated by the oscillator 2, a soliton shift fiber (wavelength modulation unit) 7 that modulates the wavelength of the seed light L0 whose spectrum has been broadened by the fiber amplifier 3 using soliton self-frequency shift to generate soliton waves LS and dispersed waves LD originating from the seed light L0, and a parametric amplification unit 12 that parametrically amplifies relatively long-wavelength pulsed light using relatively short-wavelength pulsed light among the soliton waves LS, dispersed waves LD, seed light L0, and their harmonics.

The invention relates to an optical fiber interferometer absolute displacement demodulation system and method based on gas absorption spectrum reference, and the system comprises a laser assembly which comprises a laser device and a first coupler; the detection light path assembly comprises a sensing head, an optical circulator and a first photoelectric detector, the sensing head is used for measuring displacement, the sensing head and the first photoelectric detector are both connected with the optical circulator, and the laser is connected with the optical circulator; the first reference light path assembly comprises a second photoelectric detector, and the laser is connected with the second photoelectric detector; the second reference light path assembly comprises a third photoelectric detector and a gas absorption cell, and the laser, the first coupler, the gas absorption cell and the third photoelectric detector are connected in sequence; and a data processing control assembly. According to the invention, the high-precision absolute displacement is measured remotely by using the optical fiber interferometer referenced by the gas absorption spectrum without being influenced by the wavelength stability, the wavelength modulation efficiency, the initialization phase difference and the like of the laser.

This invention discloses a method for measuring gas velocity in absorption spectra by constructing and matching absorption peak image features. The method includes: performing multiple phase-shift downsampling on a detected wavelength-modulated laser signal; reconstructing the multiple phase-shift sequences to obtain a two-dimensional grayscale image matrix containing the direct absorption spectrum profile; sharpening the two-dimensional grayscale image matrix extracted from the laser signal where the flow field velocity is zero to obtain an image template characterizing the absorption peak position; matching the position of the image template from the two-dimensional grayscale images obtained from laser detection signals in two directions within the flow field under test, based on the absorption peak position image template, to determine the offset of the absorption peak positions in the two directions; and calculating the airflow velocity using the absorption peak offsets in the two detection directions. This invention improves the accuracy of solving the absorption spectrum frequency shift at different optical depths, thereby improving the velocity measurement accuracy in complex flow fields with varying operating conditions.

This application provides a gas detection system and method based on near-infrared wavelength modulation and mid-infrared pulsed laser synergy, relating to the fields of spectroscopic gas detection and industrial flue gas monitoring. In industrial sites such as biomass power plants, hazardous waste incineration plants, and aluminum smelters, the flue gas generated in their flues has complex compositions. Traditional chemical detection methods are insufficient to meet real-time requirements, while other optical detection methods, such as Fourier transform infrared spectroscopy and ultraviolet differential spectroscopy, suffer from high costs and difficulty in avoiding water vapor interference. To address this, a system and method for detecting the concentration of gaseous pollutants in industrial flue gas based on near-infrared wavelength modulation and mid-infrared pulsed laser synergy is proposed. This system combines near-infrared wavelength modulation spectroscopy with mid-infrared pulsed direct absorption spectroscopy, employing multiple near-infrared tunable continuous lasers and mid-infrared tunable pulsed lasers. It utilizes time-division multiplexing and polling modes, combined with a common optical path design, to achieve real-time online monitoring of the concentration of various gaseous pollutants, ultimately significantly reducing the overall system cost.

An anti-interference ultra-high time-resolution laser diagnostic method and device, belonging to the field of laser diagnostic technology, utilizes an ultra-high-speed wavelength modulation device with a GHz bandwidth to achieve GHz-level wavelength modulation of the laser output light, thereby improving the time resolution of laser diagnostics from the existing hundreds of kHz level to the GHz level, reaching the nanosecond level of detection. It can accurately capture the rapid evolution process of combustion and explosion flow fields at the nanosecond to microsecond scale, filling the technological gap in ultra-high-speed detection of nanosecond-level combustion and explosion flow fields. By mixing and filtering to extract multiple harmonic signals and performing ratio normalization processing on the harmonic signals, the influence of various interference factors such as light intensity fluctuations, radiation background, particle / droplet extinction, and signal scattering attenuation is fundamentally eliminated, obtaining a stable absorption characteristic signal independent of light intensity changes. This solves the problems of signal submersion and spectral distortion in traditional optical measurements in strongly disturbed combustion and explosion environments, and can work stably in extremely complex combustion and explosion flow fields.

The embodiment of the invention provides a semiconductor package, a semiconductor device and a manufacturing method thereof. In one embodiment, a semiconductor package may include a photonic integrated circuit (PIC) die having a wavelength modulator and a heating element thermally coupled to the wavelength modulator. The semiconductor package may also include an interconnect structure on the PIC die, wherein the interconnect structure may include a plurality of conductive features and voids. The void overlaps the heating element and the wavelength modulator from a plan view. The semiconductor package may also include a plurality of conductive connectors over the interconnect structure and electrically connected to the plurality of conductive features.

The utility model discloses portable equipment for detecting hydrogen sulfide gas in odor by using a photoacoustic spectrometry, which relates to the technical field of trace gas detection equipment and comprises a detection box main body, and a rotating shaft is mounted on the outer wall of the detection box main body. Through the arrangement of the first-stage filter, the second-stage filter, the laser, the laser modulator, the sound catcher and the PLC assembly, odor is filtered through the first-stage filter and the second-stage filter, pure hydrogen sulfide gas is obtained, then the wavelength of laser emitted by the laser is modulated into a preset wavelength through the laser modulator, and the hydrogen sulfide gas is filtered through the sound catcher. Then the modulated laser is guided into the hydrogen sulfide gas, hydrogen sulfide gas molecules are transited to an excited state, the hydrogen sulfide gas molecules vibrate and produce sound in the detection box main body, sound signals of the hydrogen sulfide gas molecules are captured through the sound capture device, the sound signals are processed through the PLC assembly, and the concentration of the trace hydrogen sulfide gas in the sample gas is rapidly calculated through the amplitude of the sound signals. The hydrogen sulfide gas concentration detection efficiency is improved.

This invention belongs to the field of sensor technology. To address the challenge of existing sensors simultaneously achieving high-precision monitoring of both static and dynamic signals, this invention proposes a multi-parameter integrated fiber optic sensor and its monitoring system. The sensing cavity is divided axially into a static signal sensing area and a dynamic signal sensing area. The static signal sensing area utilizes multi-core optical fibers, each etched with a fiber grating. Wavelength demodulation of the static signal is achieved by adjusting the center wavelength shift of the fiber gratings. The dynamic signal sensing area includes a dynamic signal sensing unit, which comprises an F-P air microcavity formed between the end faces of the multi-core optical fibers. Intensity demodulation of the dynamic signal is achieved by varying the length of the F-P air microcavity. This invention employs a composite demodulation mechanism combining wavelength modulation and intensity modulation, achieving decoupled acquisition of static strain, temperature, and dynamic vibration within a single sensor.

This application discloses a quantum sensing-based lidar gas telemetry system and method. The system includes a DFB laser, a laser temperature control module, a laser current drive module, an acousto-optic modulator, a coaxial optical path for transmission and reception, an SPD single-photon detector, an amplifier circuit module, and an MCU. The temperature control module modulates the wavelength of the DFB laser, the current drive module modulates the power, and the acousto-optic modulator modulates the pulse amplitude, giving the output laser triple modulation characteristics of wavelength scanning modulation, current-gated modulation, and pulse amplitude modulation at different time scales. The modulated laser is emitted into the target space and the diffuse reflection echo is received, where the SPD single-photon detector counts single photons. The MCU performs time counting based on the counting signal to determine the target distance and performs absorption demodulation during wavelength scanning. Based on Beer-Lambert's law, the gas path integral concentration is inverted to achieve synchronous measurement of gas concentration and target distance.

In one embodiment, a semiconductor package can include a photonic integrated circuit (PIC) die comprising a wavelength modulator and a heating element thermally coupled to the wavelength modulator. The semiconductor package can also include an interconnect structure on the PIC die, wherein the interconnect structure can comprise multiple conductive structural elements and a void. In a top view, the void overlaps the heating element and the wavelength modulator. The package can further include multiple conductive connectors above the interconnect structure, which are electrically connected to the multiple conductive structural elements.

The embodiment of the invention provides a laser wavelength rapid locking and power modulation method based on feed-forward compensation, and relates to the technical field of laser wavelength modulation technologies. The method comprises the following steps: monitoring state information of a laser in parallel; generating a compensation signal based on the state information; performing fusion distribution processing on the compensation signal to obtain a composite control signal; and adjusting the wavelength of the laser based on the composite control signal. According to the invention, the problem of low laser modulation precision is solved, and the effect of improving the laser modulation precision is further achieved.

The application discloses a kind of based on surface plasmon's imaging sensing method, equipment and storage medium, by obtaining the surface plasmon interference image corresponding to the medium to be measured, based on surface plasmon interference image, the interference characteristic value corresponding to the medium to be measured is obtained, such as surface plasmon interference fringe period value and / or interference maximum spacing;Based on the preset relationship model of the corresponding relationship between the interference characteristic value and the refractive index of medium and interference characteristic parameter, the refractive index of the medium to be measured is determined, so as to realize the refractive index detection of the medium to be measured, it is favorable to improve wavelength modulation surface plasmon resonance sensing efficiency.

The application discloses a coaxial laser-ultrasonic forging printing device and a detection method, and belongs to the field of additive manufacturing technology. The device comprises a femtosecond laser, a light splitting module, a frequency-wavelength modulation unit, a time sequence-polarization control unit, a common optical path scanning module, a echo signal extraction module and a central controller. The femtosecond laser emits original wavelength laser, which is divided into an excitation beam and a detection beam by the light splitting module; the frequency-wavelength modulation unit applies a heterodyne frequency shift to the excitation beam and converts it into a frequency-doubled wavelength, so that the ultrasonic wave is excited while the impact printing layer is impacted; the time sequence-polarization control unit makes the detection beam adjustable delay to avoid the impact noise window and separates the return light path; the common optical path scanning module combines the two beams and directs the workpiece through the same galvanometer, so that the excitation point and the detection point are coincided; the echo signal extraction module extracts the ultrasonic echo signal through optical distortion-filtering and heterodyne demodulation; and the central controller analyzes defects according to the echo signal and automatically adjusts the printing parameters of the next layer. The application solves the problems of existing technology, such as integration difficulty, noise interference, weak signal and no closed-loop regulation.

The invention discloses a three-dimensional object morphology measurement method based on a Newton-like ring, and relates to the technical field of phase shift interference measurement. The method comprises the following steps: constructing a conical lens Newton ring-like model by using a conical lens and plate glass; single-color fringe patterns with different wavelengths are obtained by using incident light with different wavelengths; the air film thickness is used for calculating the optical path difference to obtain the phase change, the wavelength modulation phase shift technology is used for controlling the phase deviation by changing the wavelength of the incident light, the interference light intensity of the incident light with different wavelengths is obtained, and the phase change controlled by wavelength modulation is obtained by using the interference light intensity of the incident light with different wavelengths and the corresponding phase deviation; and calculating the object plane modulation phase of the measured object based on the phase change difference before and after the measured object is placed, and obtaining the object contour information of the measured object. According to the method, phase shift is modulated by adjusting the wavelength of incident light, vibration interference and step length calibration errors caused by mechanical phase shift can be directly avoided, and control is simple.

The present application relates to a kind of multispectral-based structured light measurement system and method, including projection system, imaging system, control and operation board card and PC machine, control and operation board card are connected with projection system and imaging system control respectively, and control and operation board card are connected with PC machine control, projection system is used to project the structured light image with coding.The present application utilizes structured light projection device to project to the measured object, by the wavelength modulation of illumination light, can project multiple different waveband structured light image respectively, then fuse these different waveband coding structured light to decode calculation when decoding calculation, can improve the adaptability of 3D structured light detection, reduce the influence of the color, material and surface roughness of the measured object on 3D detection precision, reduce noise and interference.

The application relates to a photoacoustic spectrum detection method and system with laser wavelength deviation detection, and the method comprises the following steps: calibrating a Fabry-Perot etalon; controlling the cavity temperature of the calibrated Fabry-Perot etalon through double-loop temperature control and a PID control algorithm until the cavity temperature change reaches a threshold value within a preset time; coupling the Fabry-Perot etalon with completed temperature control with a photoacoustic signal source; detecting and collecting a photoacoustic signal through a photoelectric detector, and denoising the photoacoustic signal through a second-harmonic wavelength modulation method; and reconstructing the denoised photoacoustic signal based on compressed sensing and a two-step iterative shrinkage method. Through the combination of temperature control, wavelength tuning and the compressed sensing method, the application reduces the noise of the photoacoustic signal and improves the accuracy and sensitivity of photoacoustic signal detection.