29 results about "Intensity modulation" patented technology

A waveguide is coupled at both ends to a microring (MRR) modulator in order to form a Mach-Zehnder interferometer out of the resulting unit. The coupled waveguide can be modulated independently from the MRR modulator itself with either an in-resonance photoconductive heater or a geometrically suitable PN junction. During modulation with an applied voltage to the coupler, an independent modulation can be applied to the MRR in order to compensate for wavelength shifting. Ideal lengths for the coupler are identified, as well as a spiral configuration to reduce the coupler's footprint on a photonic integrated circuit. The resulting device has reduced cross-talk between channels of a cascaded MRR system. A second coupler can be coupled to each MRR symmetrically so as to reduce insertion losses, allowing for an increased weight range at the drop and through ports.

A driving device includes a pulse intensity modulation module, a pulse width modulation module, a pulse density modulation module, and a driving module. The pulse intensity modulation module receives an image processing signal related to a pixel and generates a pulse intensity according to the image processing signal. The pulse width modulation module receives the image processing signal and generates a pulse width according to the image processing signal. The pulse density modulation module receives the image processing signal and generates a pulse density according to the image processing signal. The driving module receives the pulse intensity, the pulse width, and the pulse density and generates a driving signal to the pixel according to the pulse intensity, the pulse width, and the pulse density.

The present application discloses a fiber optic sensor and a measurement method, apparatus, and storage medium. By performing, based on the microwave signal, intensity modulation on the optical signal, then inputting the modulated optical signal into the fiber optic containing the weak reflection grating array, a reflected signal is obtained. Thereafter by performing dispersion compensation on the amplified partial reflected signal, and based on the dispersion-compensated reflected signal and the non-dispersion-compensated reflected signal, the change amounts respectively corresponding to positions in the fiber optic containing the weak reflection grating array are determined.

This invention proposes a method for fabricating three-dimensional photonic crystals based on the standing wave effect, comprising: ultrasonically cleaning a silicon substrate; spin-coating photoresist onto the cleaned silicon substrate surface, followed by a pre-baking process to form a resist layer on the silicon substrate surface; performing a first exposure on the resist layer using a dual-beam laser interferometry system to form horizontal interference fringes within the resist layer, while the incident light interferes with the reflected light from the silicon substrate to generate a vertical standing wave effect; keeping the silicon substrate unchanged, rotating the sample around a vertical axis, and performing a second exposure using the same parameters to form a second set of interference fringes in the horizontal direction, which superimposes with the first exposure to form a two-dimensional periodic light intensity distribution, while the vertical standing wave effect superimposes to enhance the intensity modulation depth.

This invention discloses a fiber optic deformation sensor and deformation measurement method based on Sagnac interferometry. The sensor includes a Sagnac interferometer optical path and a photoelectric conversion module. The Sagnac interferometer optical path includes a sensing fiber loop, which includes at least one segment of polarization-maintaining fiber. The polarization-maintaining fiber has an axially stretchable elastic helical structure. The interference light intensity output by the Sagnac interferometer optical path changes monotonically with the axial stretch of the polarization-maintaining fiber. The photoelectric conversion module receives the interference light intensity and converts it into an electrical signal. This invention achieves wide-range deformation measurement while maintaining high sensitivity by setting the polarization-maintaining fiber as an axially stretchable elastic helical structure. It uses an intensity modulation method to directly convert the signal into an electrical signal through a photodetector, eliminating the need for a spectrometer, significantly reducing system cost. Furthermore, the structure is simple and easy to fabricate, making it widely applicable to various high-precision, large-deformation real-time monitoring scenarios.

This application discloses an optical fiber detection device, an optical line terminal, and a method for identifying events, belonging to the field of optical communication technology. In the optical fiber detection device, a light source outputs an optical signal to a modulation module. An encoded pulse generation module outputs encoded pulses to the modulation module. The modulation module performs phase modulation and intensity modulation on optical signal segments within different time periods of the optical signal according to the encoded pulses, obtaining and outputting optical pulse signals to the optical fiber, causing the optical fiber to output a return signal. The light source also outputs an optical signal to a photodetector module. The photodetector module acquires and outputs an electrical signal to a processing module based on the optical signal and the return signal. The electrical signal includes electrical signal segments within different time periods corresponding to the optical signal segments. The processing module performs phase demodulation and intensity demodulation on the electrical signal segments within different time periods, obtaining an event signal used to identify events occurring in the optical fiber. This application can achieve accurate event identification, covering various event identification scenarios.

A coherent detection method, apparatus, and system are disclosed. The method may include: receiving an intensity-modulated optical signal transmitted by a transmitting end, where the intensity-modulated optical signal is obtained by intensity modulation performed by the transmitting end on an original signal; performing phase modulation on a local oscillator optical signal to obtain a phase-modulated local oscillator optical signal; and mixing the intensity-modulated optical signal and the phase-modulated local oscillator optical signal, and then performing photoelectric detection, analog-to-digital conversion, and digital signal receiving processing in sequence to recover the original signal.

An electrical signal measurement device (2A) is provided with: a signal conversion unit (30) for intensity-modulating measurement light on the basis of a time-waveform electrical signal to be measured, and outputting the signal as an optical signal corresponding to the electrical signal; a waveform measurement unit (40) that measures the time waveform of the optical signal; and a waveform analysis unit (52) that finds the time waveform of the electrical signal on the basis of the measurement result of the optical signal. The waveform measurement unit (40) includes a streak tube (42) including a photoelectric surface to which an optical signal is input, a scanning electrode, and a fluorescent surface, an imaging element (44) that captures a fluorescent image generated on the fluorescent surface and outputs a waveform image, and an input optical system (41) that inputs the optical signal to the photoelectric surface, and the waveform analysis unit (52) obtains a temporal waveform of an electric signal on the basis of the waveform image. The input optical system (41) inputs the optical signal into the photoelectric surface as a linear optical image extending in a direction intersecting the scanning direction. Therefore, the electric signal measuring device and the measuring method can measure the time waveform of the electric signal at high speed.

A method and system for optical communication with simultaneous transmission of bits of information and distribution of cryptographic key bits using laser beam intensity modulation in a transmitter and using direct detection in a receiver. A laser beam of a specific optical carrier wavelength is modulated according to a common set of modulation symbols encoding simultaneously information bits and cryptographic key bits, symbols differing in at least one parameter selected from the group with light intensity and time delay, wherein the symbols used to encode different key bits differ in light intensity.

The application provides a radio frequency comb generator, a preparation method and a signal generation method, and belongs to the technical field of radio frequency microwave signal sources.The application comprises a silicon substrate, an insulating layer arranged on the silicon substrate, a resonant cavity formed in the insulating layer, a gate electrode arranged at the bottom of the resonant cavity, a source electrode and a drain electrode arranged on both sides of the resonant cavity, a two-dimensional material diaphragm bridged between the source electrode and the drain electrode and suspended above the resonant cavity, an electric parameter excitation circuit connected with the gate electrode and used for applying a direct current bias voltage and an alternating current pumping voltage between the gate electrode and the two-dimensional material diaphragm, and a light direct driving unit used for applying intensity modulation laser to the two-dimensional material diaphragm.The application realizes the cooperative work of electric parameter excitation and light direct driving, has the advantages of low power consumption, large comb tooth spacing, strong adjustability, easy on-chip integration and the like, and can be widely applied to multiple fields.

This invention relates to the field of differential wavefront sensing angle technology, and particularly to a method for estimating and compensating for lateral offset in differential wavefront sensing angles. The method includes: independently modulating the reference beam and the measurement beam with sinusoidal intensity, enabling the two beams to carry different frequency signatures, thus achieving power decoupling in the interference signals; incident on a four-quadrant photodetector and interfering, acquiring and processing the interference electrical signals to obtain four digital test signals; executing three independent signal processing branches in parallel on the four digital test signals to calculate the lateral offset of the reference beam and the measurement beam, as well as the pitch and yaw angle observations including pseudo-differential phase errors; constructing pseudo-differential phase components, and subtracting these components from the pitch and yaw angle observations in real time to compensate for and suppress lateral offset errors. The advantages are: real-time extraction of the amplitude of the two interferometric beams based on intensity modulation and estimation of lateral offset, effectively suppressing errors and improving angle measurement accuracy.

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.

The application discloses a kind of ice layer parameter inversion system and method based on photoacoustic effect inversion, it is related to marine acoustic technology field, realize non-contact, high efficiency, end to end, high accuracy, physically interpretable detection sea ice parameter, solve the problems of poor real-time in prior art, artificial dependence, complex calculation, the system includes: laser excitation module, for emitting intensity modulated laser to the measured area of sea ice surface;Signal acquisition module is used to receive the target sound wave associated with the time-frequency characteristics of laser;The target sound wave is generated by the photoacoustic effect of the measured area irradiated by laser;Data processing module is used to restore the ice layer parameter of the measured area based on the target sound wave according to the preset inversion process.

This invention discloses an optimization device and method for laser spot edge diffraction, relating to the field of optical instrument technology. The optimization device includes two sets of guiding mechanisms, two sets of driving mechanisms, and two sets of aperture pairs. Each aperture pair includes two opposing aperture plates, the edges of which are used to define the light transmission boundary and have a serrated structure. The driving mechanisms drive the two aperture plates in the same set to move synchronously in opposite directions along the guiding direction. The positions of the two aperture pairs are independently controlled to combine and form different light transmission boundaries. In the optimization method, the positions of the two aperture pairs are adjusted according to the edge morphology of the laser beam to be optimized, and the laser beam is made to pass through the target light transmission boundary for edge intensity modulation. Through the technical solution of this invention, the edge diffraction caused by traditional straight-edge apertures is reduced, and the edge smoothness of the laser beam, the flexibility of light transmission boundary adjustment, the adaptability to different spot morphologies, the shaping consistency, and the processing stability are improved.

The application provides a high-precision laser ranging system and method based on differential signal demodulation, comprising a laser, a first optical circulator, a second optical circulator, a two-port Mach-Zehnder modulator, an optical lens, a mirror, an RF circuit board, a PC and a differential signal processing system; the laser signal is subjected to first intensity modulation by the two-port Mach-Zehnder modulator, and the first modulated laser signal is transmitted to the optical lens; after being irradiated by the mirror, the laser signal is folded back to the optical lens, and then enters the two-port Mach-Zehnder modulator again through the second port of the optical lens to be subjected to second modulation, thereby obtaining a differential signal; the differential signal enters the differential signal processing system to be analyzed, thereby obtaining a single-end signal; based on the single-end signal, an optical intensity extreme value is obtained, and a distance to be measured is calculated. The technical scheme of the application improves the ranging precision, and an absolute distance result with high precision is obtained.

The present application discloses a fiber optic sensor and a measurement method, apparatus, and storage medium. By performing, based on the microwave signal, intensity modulation on the optical signal, then inputting the modulated optical signal into the fiber optic containing the weak reflection grating array, a reflected signal is obtained. Thereafter by performing dispersion compensation on the amplified partial reflected signal, and based on the dispersion-compensated reflected signal and the non-dispersion-compensated reflected signal, the change amounts respectively corresponding to positions in the fiber optic containing the weak reflection grating array are determined.

This invention discloses a device and method for self-testing and calibration coefficient correction of a radiation pyrometer system, relating to the field of radiation temperature measurement technology. The device comprises a broadband light source, an intensity modulation unit, a first multimode fiber, a return light unit, a second multimode fiber, and a multichannel radiation pyrometer. The return light unit shares the second multimode fiber with the object under test, ensuring that the transmission path of the return light monitoring signal is consistent with that of the radiation signal under test. The method includes system self-testing and calibration coefficient correction: Transmission link loss is calculated by comparing the return light amplitude of the reference and actual states, achieving system status self-testing and abnormal channel location; initial calibration coefficients are calculated based on standard temperature source measurements combined with Planck's radiation law, and then the transmission loss factor is calculated through changes in the return light signal amplitude to dynamically correct the calibration coefficients; finally, the spectral radiance is calculated using the corrected coefficients, and the impact temperature to be measured is obtained through least squares fitting. This invention enables rapid system self-testing and dynamic coefficient correction.

The application belongs to the technical field of secret communication, and discloses a chipped quantum key distribution system, wherein a sending end comprises an encoding chip of a strength modulation module and an adjustable attenuation module; the strength modulation module is used for chopping an optical pulse signal into two sub-pulses with a time difference of T, and respectively performing intensity modulation on the two sub-pulses to generate a signal state and a decoy state of a time-phase encoding quantum state; the adjustable attenuation module is used for attenuating the time-phase encoding quantum state to a single-photon level; and a receiving end comprises a decoding chip; the decoding chip comprises a quadrature polarization delay module, and a delay difference of TM and TE polarization modes is T. Compared with the prior art, the application can realize time-phase encoding, and reduce the complexity of the sending end by respectively performing intensity modulation on two sub-pulses after chopping an optical pulse into the two sub-pulses; the decoding chip adopts a passive basis selection and a non-equal arm interferometer with a symmetrical structure, and simultaneously realizes polarization-independent receiving and decoding, thereby improving the stability of the system.

The semiconductor light-receiving element (110) disclosed herein comprises: an InP substrate (1); an n-type semiconductor layer (2a) formed on the InP substrate (1); an electron transit layer (3) formed on the n-type semiconductor layer (2a) and constructed of a digital alloy; an n-type electric field mitigation layer (12) formed on the electron transit layer (3); a multiplication layer (13) formed on the n-type electric field mitigation layer (12); a p-type electric field mitigation layer (14) formed on the multiplication layer (13); and a light-absorbing layer (5) formed on the p-type electric field mitigation layer (14).

A waveguide coupled cavity structure configured to exhibit Fano resonance, such as asymmetric Fano resonance or symmetric Fano resonance (inverse Lorentz resonance), is used in an optical receiver or method for directly detecting a coherent optical signal by converting phase modulation of the coherent optical signal into intensity modulation of the optical signal. The waveguide coupled cavity structure is designed such that a transmission spectrum of the Fano resonance overlaps a spectrum of the modulated coherent optical signal to suppress transmission of at least one sideband of the modulated coherent optical signal through the structure, the sideband suppression being asymmetric with respect to a carrier frequency of the modulated coherent optical signal. The invention can be used to directly detect more advanced coherent modulation formats, such as quadrature phase shift keying (QPSK) signals and high order quadrature amplitude modulation (n-QAM) signals.

The application discloses a kind of based on multi-channel diffraction grating ultrafast laser intensity modulation method and system, method includes: placing optical element according to optical path design, alignment optical axis, adjust the output direction of ultrafast laser and system main optical axis coincide, complete preliminary calibration.Laser is split by blazed grating, focused to each channel electro-optic modulator by microlens array;8 independent electric modulation signals are generated synchronously, and after loading, the intensity modulation of multi-channel sub-beam is completed, and then synthesized by confocal aspherical mirror to eliminate aberration.When the modulation contrast is less than 30dB, based on fast and slow deviation grading mechanism: high-frequency dynamic deviation is compensated by real-time voltage correction optical path, low-frequency slow change deviation is compensated by temperature control refractive index and fine adjustment grating angle to reduce crosstalk, until standard is reached.Finally, linkage control mechanism is established, and parameters are monitored and dynamically adjusted in real time.Modulation speed, precision and stability are improved.

In one aspect, the disclosure relates to a method for correcting distortions or aberrations in a multi-photon microscopy image, the method including at least: (a) illuminating the sample; (b) imaging the illuminated sample with an imaging device having one or more detection elements that receive a signal from the sample; and (c) processing the image using a scattering correction and a phase correction. The phase correction can be a low-order deformable mirror adaptive optics correction with a hardware component and a software component. In some aspects, a spatial light modulator can be employed as a low-order phase correcting device. The scattering correction can be intensity scattering correction, phase scattering correction, or both, and can be performed with a high-order digital micromirror device with binary intensity modulation or a phase or intensity high-order spatial light modulator device. Also disclosed are methods of imaging complex tissue in living subjects.

The present application relates to the technical field of image processing, and discloses a physical guiding low-light image enhancement method based on joint modeling of illumination and exposure, wherein a low-light image to be processed is input into an illumination and exposure prediction module to perform feature extraction and generate a local illumination map, and a global exposure factor is derived based on the local illumination map; the low-light image to be processed, the local illumination map and the global exposure factor are input into a double condition adaptive enhancement module, intensity modulation is performed in combination with the global exposure factor, spatially guided interactive operation is performed in combination with the local illumination map, and an enhanced image is output after feature reconstruction; in the model training stage, a normal light reference image is acquired, reconstruction loss and structural consistency loss are calculated, exposure consistency loss is calculated for the global exposure factor, and an overall loss function is constructed to drive an optimizer to jointly optimize network parameters. The present application realizes adaptive calibration of local space and global brightness, effectively suppresses image noise while recovering dark details.

This disclosure relates to non-destructive estimation of coating layer thickness based on sweep frequency photo acoustic guided wave technique. Coating of a substrate / surface protects it from wear, corrosion and serves the cosmetic aspect, hence making coating technology is an essential part industrial process. The existing techniques for coating thickness determination are either destructive or requires a prior knowledge of the refractive index of the surface under investigation or use of sophisticated instrumentation, complicated procedure and harmful radiation during industrial deployment. The disclosure utilizes an intensity modulated Continuous Wave (CW) laser diode to excite a sample thus, making the technique a partially contact based method. Further a calibration curve is plotted by determining a frequency spectrum and resonance frequency. The calibration curve is used for estimation of a coating layer thickness.

This invention relates to the field of semiconductor electrical measurement technology, and particularly to a carrier-trap resolution measurement system and method based on axial magnetic field modulation. The system includes a light source and intensity modulation unit, an optical microscope / confocal unit, an axial magnetic field modulation device, a control unit, an electrical measurement unit, and a data acquisition and digital phase-locked loop unit. The axial magnetic field modulation device employs a symmetrical permanent magnet ring and a vertical light-transmitting barrel structure, combined with a soft magnetic permeability modulation wheel, to form a stable alternating axial magnetic field perpendicular to the sample, with the optical path coaxially incident vertically. The method includes sample clamping and alignment, parameter initialization, synchronous acquisition of longitudinal resistance signals and transverse Hall signals, spectrum confirmation, digital phase-locked loop analysis, and multi-external parameter scanning output. The advantages are: reducing mechanical vibration and optical path interference by rotating the soft magnetic permeability modulation wheel, thus improving signal stability; and achieving weak Hall signal extraction by combining phase-locked loop detection, efficiently separating carrier and trap responses.

The semiconductor inspection apparatus (1A) includes: an inspection optical system (11) that irradiates a semiconductor device (D) with a probe light and outputs reflected light; an optical measurement unit (20) that detects the reflected light and outputs an electrical signal showing the time waveform of its intensity changing over time; a signal conversion unit (30) that modulates the intensity of the measurement light based on the electrical signal and outputs an optical signal corresponding to the electrical signal; a waveform measurement unit (40) that measures the time waveform of the optical signal; and a waveform analysis unit (52) that calculates the time waveform of the electrical signal based on the measurement result of the optical signal. The waveform measurement unit (40) has: a stripe tube including a photoelectric surface, a scanning electrode, and a fluorescent surface that includes an input optical signal; and an imaging element that captures a fluorescent image generated on the fluorescent surface and outputs a waveform image; the waveform analysis unit (52) calculates the time waveform of the electrical signal based on the waveform image. Thus, a semiconductor inspection apparatus and inspection method capable of high-speed measurement of the time change of the intensity of reflected light when a probe light is irradiated onto a semiconductor device are realized.