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55 results about "Modulation bandwidth" patented technology

Modulation Bandwidth. The Modulation Bandwidth is defined as the maximum rate of change in the output frequency that can be attained using the Control Voltage of a VCXO.

Distributed feedback laser with double-layer grating structure

The invention provides a distributed feedback laser with a double-layer grating structure, and relates to the technical field of lasers, the laser forms an InGaAlAs multi-quantum well active region, an upper sampling grating layer and a lower phase shift grating layer on an n-type InP substrate in sequence, the upper grating layer is designed based on a reconstruction equivalent chirp technology, and the lower phase shift grating layer is designed based on a reconstruction equivalent chirp technology. Two sections of asymmetric modulation areas with sampling periods linearly gradually changing in opposite directions are arranged in the axial direction of the resonant cavity, and the lower grating layer is a quarter-wave phase shift grating matched with the period of the upper seed grating. Through the synergistic effect of equivalent phase modulation and phase shift generated by the double-layer grating, the photon density distribution in the cavity can be improved, the longitudinal space hole burning effect can be weakened, the sensitivity to end face phase fluctuation can be reduced, high single-mode power and large modulation bandwidth can be realized in a wide temperature range, and the double-layer grating is suitable for a high-speed optical communication and coarse wavelength division multiplexing transmission system.
Owner:XINCHEN SEMICON (SUZHOU) CO LTD

Semiconductor Laser and Two-Channel Laser Array

A semiconductor laser includes a distributed feedback (DFB) region including an active layer and a uniform grating and two distributed Bragg reflector (DBR) region including an core layer and a uniform grating and optically coupled to respective ends of the DFB region and lengths of the DFB region and the DBR regions in a waveguide direction are set so that a photon-photon resonance frequency is in a range from 40 GHz to 50 GHz when an operating temperature is between 25 degrees and 75 degrees. The semiconductor laser optimizes a PPR effect and enables maximizing a modulation bandwidth.
Owner:NT T INC

Multi-physics co-simulation method and device for high-speed silicon-based electro-optical modulator

The embodiment of the invention provides a multi-physical field collaborative simulation method and device for a high-speed silicon-based electro-optical modulator, and the method comprises the steps: building a physical model of the electro-optical modulator, carrying out the simulation under different bias voltage and temperature conditions, solving a Poisson equation, a carrier continuity equation and a drift diffusion transport equation, and obtaining the corresponding carrier concentration distribution; performing small-signal simulation analysis on the model to obtain corresponding PN junction electrical characteristic parameters; performing waveguide optical mode simulation on the model to obtain corresponding electric field mode distribution and effective refractive index, and calculating the effective refractive index and absorption coefficient change of the waveguide; constructing a traveling wave electrode model, simulating the traveling wave electrode model to solve an S parameter of a traveling wave electrode, and determining a distribution parameter of the no-load traveling wave microstrip line; a load traveling wave transmission line model is constructed in combination with PN junction electrical characteristic parameters, and based on the model, the frequency response characteristics and the modulation bandwidth of the electro-optical modulator at different temperatures are determined, so that the accuracy of a simulation result can be improved.
Owner:CASIC DEFENSE TECH RES & TEST CENT

Frequency modulated continuous wave laser radar signal generation method, frequency modulated continuous wave laser radar signal detection method and frequency modulated continuous wave laser radar signal generation system

The invention discloses a frequency-modulated continuous wave laser radar signal generation method, a frequency-modulated continuous wave laser radar signal detection method and a frequency-modulated continuous wave laser radar signal detection system. The system comprises a transmitting end and a receiving end, wherein the transmitting end determines a frequency guard interval between a frequency-modulated continuous wave signal and zero frequency according to a modulation bandwidth of a radar signal and a line width of a transmitting laser; generating a frequency modulation continuous wave signal according to the frequency protection interval, modulating the frequency modulation continuous wave signal, generating radar detection signal light which is to be sent and contains residual carrier waves, performing power amplification on the radar detection signal light, and transmitting the radar detection signal light by using an optical lens; the receiving end receives the reflected signal light reflected by the target; filtering, beat frequency and coherent detection are carried out on the reflected signal light and the radar detection signal light to obtain an electric signal, and the electric signal is converted into a digital signal; performing electric domain filtering on the digital signal, and extracting a residual carrier and a beat frequency signal; performing phase noise compensation on the beat frequency signal based on the residual carrier to obtain a signal after phase recovery; and estimating the distance and the relative speed of the target based on the residual carrier and the phase-recovered signal.
Owner:PEKING UNIV

Power amplification system for high modulation bandwidth

A power amplification system is provided herein. In certain embodiments, the power amplification system comprises: a power amplifier configured to amplify an input radio frequency (RF) signal to generate an output RF signal when powered by a supply voltage and biased by a biasing signal; an envelope tracker configured to generate an envelope signal that changes in relation to an envelope of the input RF signal; a mode controller configured to set an envelope tracking (ET) mode of the power amplification system based on a modulation bandwidth of the input RF signal; a supply voltage controller configured to control the supply voltage based on the envelope signal when the ET mode is set to a first mode; and a bias controller configured to control the biasing signal based on the envelope signal when the operation mode is set to a second mode.
Owner:SKYWORKS SOLUTIONS INC

High-efficiency power amplifier with extended harmonic modulation bandwidth and modulation method thereof

This invention discloses a high-efficiency power amplifier with extended harmonic modulation bandwidth and its modulation method. A harmonic control circuit unit is added to the input terminal of the final stage die of the power amplifier. The extended harmonic control unit includes a second harmonic modulation circuit and a first parasitic element of the power amplifier back hole. The second parasitic element of the source back hole of the final stage transistor participates in modulation. Considering the parasitic effect of the power amplifier and the back hole at the source of the die, the harmonic modulation bandwidth is further widened by adjusting the harmonic control circuit unit, which effectively improves the working efficiency of the amplifier.
Owner:NO 55 INST CHINA ELECTRONIC SCI & TECHNOLOGYGROUP CO LTD

Electro-optical modulator and optical device

The present disclosure belongs to the technical field of optical communications. Provided are an electro-optical modulator and an optical device. The electro-optical modulator comprises a light source and a modulation structure. The modulation structure is located on an emergent light path of the light source; and the modulation structure comprises a modulation layer, a first electrode, a second electrode and an electric-field forming layer, wherein the first electrode, the second electrode and the electric-field forming layer are used for generating an electric field on the modulation layer so as to change the carrier concentration of the modulation layer. By means of the present disclosure, the electro-optical modulator uses the modulation structure to modulate, into pulsed light, continuous light emitted by the light source, so that the modulation bandwidth of the electro-optical modulator is not affected by parameters of the light source itself, and the modulation bandwidth of the electro-optical modulator can thus be improved.
Owner:HUAWEI TECH CO LTD

Bandwidth adaptation in a transmission circuit

Bandwidth adaptation in a transmission circuit is provided. The transmission circuit includes a power amplifier circuit that amplifies a radio frequency (RF) signal based on a modulated voltage, an envelope tracking integrated circuit (ETIC) that generates the modulated voltage based on a modulated target voltage, and a transceiver circuit that generates the RF signal and the modulated target voltage. The RF signal may have a wide modulation bandwidth but the ETIC may have a lower bandwidth limit, which can cause distortion in the modulated voltage and the RF signal. In this regard, the transceiver circuit is configured to generate the modulated target voltage in a lower bandwidth than the bandwidth limit when the modulation bandwidth of the RF signal exceeds the bandwidth limit of the ETIC. As such, the transmission circuit can process the RF signal across the wide modulation bandwidth without causing distortion in the RF signal.
Owner:QORVO US INC

A method for detecting the strength of parasitic feedback of a butt joint end face of a butt joint structure DFB laser chip

The application provides a method for detecting parasitic feedback intensity of a butt joint end face of a butt joint structure DFB laser chip, belongs to the technical field of semiconductor optoelectronic device manufacturing, and is used for solving the technical problem that the existing DFB laser chip provided with an end face butt joint structure generates parasitic light feedback at the butt joint end face, and influences spectral characteristics and modulation bandwidth; the application adopts a spectrometer to perform high-precision spectral testing on the DFB laser chip to obtain sampling data, analyzes and calculates the jitter state formed by the high and low light intensity of different wavelength points of the obtained test spectrum appearance, judges whether internal end face light feedback exists in the butt joint structure, analyzes the relative intensity of the end face feedback of the butt joint structure, and obtains the parasitic feedback intensity. The application can judge whether internal end face light feedback exists in the butt joint structure and analyze the relative intensity of the butt joint end face feedback, thereby providing an optimization direction and basis for end face butt joint process and optical waveguide design; and the application does not need to increase new testing equipment, and has good universality.
Owner:HENAN SHIJIA PHOTONS TECH

A radio frequency microwave amplifier with extended modulation bandwidth

The application provides a radio frequency microwave amplifier for expanding modulation bandwidth, and relates to the technical field of radio frequency microwave circuits.The amplifier comprises an active device current source end face parasitic capacitor, a first inductor, a first capacitor, a video bandwidth expansion circuit, an output circuit and a target load; the first end of the first inductor is connected with the first end of the active device current source end face parasitic capacitor and the first end of the output circuit respectively, and the second end of the first inductor is connected with the first end of the first capacitor and the first end of the video bandwidth expansion circuit respectively; the second end of the output circuit is connected with the target load; and the second end of the first capacitor is grounded.The application can effectively break through the limitation of traditional radio frequency microwave amplifiers in modulation bandwidth, so that the amplifier can process modulation signals in a wider frequency range, and meet the demand of modern communication systems for high-speed and large-capacity data transmission.
Owner:CHENGDU YUXI SEMICON TECH CO LTD

A space laser communication system based on pulsed light modulation and demodulation

This invention discloses a space laser communication system based on pulsed light modulation and demodulation, comprising: a transmitter and a receiver; the transmitter includes a pulsed light source, a driving modulation circuit unit, and a transmitting optical path; the pulsed light source carries pulsed signal light; the driving modulation circuit unit directly modulates the pulsed signal light; the transmitting optical path transmits the modulated pulsed signal light into space; the receiver includes a receiving optical path, an optical signal detection unit, and a signal demodulation unit; the receiving optical path receives the modulated pulsed signal light; the optical signal detection unit performs signal conversion and amplification on the modulated pulsed signal light; and the signal demodulation unit performs signal demodulation and data recovery on the modulated pulsed signal light. This invention utilizes a direct modulation pulsed light source, saving modulation bandwidth and reducing the complexity of signal modulation and demodulation at both the transmitter and receiver, making it suitable for constructing low-power and low-cost space laser communication systems.
Owner:NAVAL UNIV OF ENG PLA

Electro-optical modulator with low driving voltage and preparation method thereof

According to the electro-optical modulator with the low driving voltage and the preparation method of the electro-optical modulator, the modulation electrode is prepared by adopting the superconducting material instead of conventional metal, so that the ohmic loss of the modulation electrode can be eliminated in a low-temperature working environment, a microwave modulation signal can be transmitted with extremely low loss, the bandwidth of the electro-optical modulator is remarkably improved, and the performance of the electro-optical modulator is improved. Due to the characteristic of extremely low transmission loss of the superconducting modulation electrode, the interaction between the electrode and a light field is enhanced by adopting a longer electrode design on the premise of not introducing obvious signal attenuation, so that the half-wave voltage can be effectively reduced while the ultra-high modulation bandwidth of the electro-optical modulator can be maintained, and the performance of the electro-optical modulator is improved. Therefore, a millivolt-level weak electric signal can be efficiently responded, and a cross-temperature zone interconnection system with higher energy efficiency can be constructed; besides, by means of the formed high-quality electro-optical thin film layer, waveguide transmission loss is greatly reduced, photorefractive damage is avoided under high optical power, the reliability of the whole optical interconnection core device is remarkably improved, and the service life of the whole optical interconnection core device is remarkably prolonged.
Owner:SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI

Silicon-based millimeter-wave broadband compact dual-drive doherty power amplifier

The application relates to a silicon-based millimeter wave broadband compact double-drive high-efficiency Doherty power amplifier, belonging to the technical field of radio frequency integrated circuits, comprising an input quadrature coupler, a main and auxiliary two power amplifier paths and a broadband load modulation output network; wherein the power amplifier path adopts a differential common source and common gate unit with cross-coupling capacitance and a double-mode drive topology to improve the gain and efficiency of the millimeter wave frequency band; the output network adopts a slow wave transmission line structure combined with a cascade coupling line pair to realize broadband active load modulation and absorb transistor parasitic capacitance, and simultaneously optimize the chip area. Thus, the problem that the efficiency and bandwidth are difficult to be considered simultaneously due to the limited load modulation bandwidth and the decreased transistor gain of the traditional silicon-based millimeter wave Doherty power amplifier is solved.
Owner:XIDIAN UNIV

Multi-mode power management device

A multi-mode power management device is provided. In embodiments disclosed herein, the multi-mode power management device may be configured to operate in different power management modes across a wide modulation bandwidth range (e.g., 80 KHz to 200 MHz or more). The multi-mode power management device includes a power management integrated circuit (PMIC) and an envelope tracking integrated (ET) circuit (ETIC) implemented in a separate die. The PMIC is configured to generate a low frequency current and a low frequency voltage. The ETIC is configured to generate a pair of ET voltages. Depending on the power management mode, the multi-mode power management device may selectively output one or more of the ET voltage and the low frequency voltage to different stages (e.g., a driver stage and an output stage) of a power amplifier circuit, therefore, the optimal efficiency and linearity of the power amplifier circuit can be maintained across the wide modulation bandwidth range.
Owner:QORVO US INC

Frequency modulated continuous wave lidar system

PendingCN122307577AModulation bandwidthGain
This application provides a frequency-modulated continuous wave lidar system, comprising a programmable gain circuit and a laser. The programmable gain circuit includes a control module, a digital-to-analog converter module, and a programmable gain amplifier. The laser generates a detection beam. The control module generates a digital signal and controls the gain of the programmable gain amplifier according to the modulation bandwidth of the laser. The programmable gain amplifier, in response to the gain control of the control module, amplifies the analog signal to match the modulation bandwidth of the laser and uses the amplified analog signal as a modulation signal to modulate the detection beam. The modulated detection beam is emitted into the detection space. This application solves the problem of high resource requirements of the back-end receiving system in related technologies' frequency-modulated continuous wave lidar systems, thereby achieving optimal bandwidth modulation and ranging effects.
Owner:北京集光智研科技有限公司

DAS system based on multi-band linear sweep frequency pulse

The utility model discloses a DAS system based on multi-band linear sweep frequency pulses, and relates to the technical field of distributed sound wave sensing. The DAS system comprises a narrow linewidth laser, an optical fiber coupler, a phase modulator, an electro-optical modulator, an erbium-doped optical fiber amplifier, an optical fiber circulator, a dense wavelength division multiplexer, a photoelectric balance detector, a data acquisition card, an arbitrary waveform generator, a direct current source and the like. According to the system, the phase modulator is used for modulating constant-amplitude multi-frequency continuous light, the frequency number of light waves is related to the harmonic number of microwave modulation signals, the frequency interval is determined by the fundamental frequency of the microwave modulation signals, and the continuous light frequency can be flexibly modulated by adjusting the microwave modulation signals, and the modulation bandwidth is large; detected beat frequency signals are compressed into single-frequency signals through pulses, phase information of the single-frequency signals is demodulated, vibration signals along the sensing optical fiber can be detected, the spatial resolution of the system depends on the chirp frequency sweeping range, and the spatial resolution is high.
Owner:HARBIN INST OF TECH +1

A high-speed light emitting diode underwater wireless optical communication system and method

The application provides a high-speed light-emitting diode underwater wireless optical communication system and method, and belongs to the technical field of underwater optical communication; a transmitting end comprises successively connected adaptive coding module, 16QAM mapping module, OFDM modulation module, digital-analog conversion module and LED array light source module; a receiving end comprises successively connected photoelectric detection module, signal processing module of integrated post-equalization circuit, analog-digital conversion module, digital filter module, OFDM demodulation module, phase estimation module, 16QAM demapping module and Viterbi decoding module; the application provides a high-speed LED underwater wireless optical communication system and method based on 16-order quadrature amplitude modulation-quadrature frequency division multiplexing and hardware equalization, adopts hardware equalization to effectively expand the modulation bandwidth of the LED light source, significantly improves the transmission performance of high-frequency signals, and sufficiently utilizes the frequency spectrum resources through high-order modulation, and significantly improves the data transmission rate of the system.
Owner:OCEAN UNIV OF CHINA

Electro-optic modulator, method of making and modulation test system therefor

The application discloses an electro-optical modulator, a preparation method thereof and a modulation test system, and relates to the technical field of optical communication. The electro-optical modulator comprises a field effect transistor and a micro-nano optical fiber. The field effect transistor comprises a silicon substrate, a dielectric layer, a heterojunction and an electrode layer which are sequentially stacked. The electrode layer comprises a source electrode and a drain electrode which are arranged at two ends of the heterojunction respectively. The micro-nano optical fiber comprises an input optical fiber, a first tapered transition optical fiber, a middle optical fiber, a second tapered transition optical fiber and an output optical fiber which are sequentially connected. The middle optical fiber has a fiber micro-ring with a ring structure, and the fiber micro-ring is arranged on the heterojunction. The electro-optical modulator is a full-fiber electro-optical modulator, and the coupling mode is simple. The electro-optical modulator replaces traditional section coupling or grating coupling with fiber-fiber light field coupling, thereby avoiding the problem of mode field matching. Evenly, the electro-optical modulator can realize plug-and-play, near-zero coupling loss optical interconnection and optical modulation. The electro-optical modulator has the advantages of fast modulation speed, low cost, high modulation bandwidth and the like.
Owner:SHENZHEN UNIV +1

LED modulation bandwidth fast test system and test method

The application discloses a kind of LED modulation bandwidth fast test system, including direct-current power supply;Biaser;Laser, for exciting LED sample to emit light, realize the transformation of optical signal-electrical signal-optical signal;Transmission component, for focusing overall light;Optical filter, for excluding the influence of laser on LED light emission;Photoelectric detector, detect the light signal emitted by LED, and change into electrical signal output;Vector network analyzer, analyze two-port signal to draw frequency response curve, so as to obtain the modulation bandwidth of LED.The application can realize the function of testing the communication performance of LED without packaging, and can realize the function of measuring the modulation bandwidth of multiple LEDs simultaneously by laser scanning.Using the device of the application can realize fast measurement, and optical excitation can achieve the effect of zero damage to LED sample.
Owner:NANJING UNIV

A novel traveling wave switch modulator

The present application relates to direct modulation and sub-terahertz-terahertz communication technology field, especially to a kind of novel traveling wave switch modulator, including input end and output end waveguide, main transmission line of sub-terahertz signal transmission, intermediate frequency feed circuit, two resonant coupling traveling wave switch unit.Schottky diode is combined with microstrip line, to form a kind of double-resonant dynamic coupling unit, coupling unit uses Z-shaped matching structure, utilize intermediate frequency voltage signal to control the electron transport of diode, change the coupling strength on traveling wave switch, so as to realize the amplitude modulation of sub-terahertz wave.In the realization of high-speed amplitude modulation, the insertion loss is low, the on-off ratio is large, and the working performance is good;And the present application is simple in structure, in the case of using only two dynamic structure units, 25.4dB on-off ratio is obtained at zero phase difference point.By adjusting control voltage, high-speed modulation can be realized, and the phase difference is only 3.66 degrees in the whole control voltage conversion process, with higher modulation bandwidth.
Owner:YANGTZE DELTA REGION INST OF UNIV OF ELECTRONICS SCI & TECH OF CHINE (HUZHOU)

Terahertz dual-band radar transceiver and radar system

The embodiment of the invention provides a terahertz dual-band radar transceiver and a radar system, and belongs to the technical field of communication. The transceiver comprises a terahertz voltage-controlled oscillator (VCO), a buffer amplifier, a double-harmonic generator and a terahertz double-frequency on-chip antenna which are connected in sequence. The method is characterized in that a single radio frequency link and an antenna are adopted to realize dual-band operation: in a transmitting mode, after a high-frequency signal generated by a VCO is amplified, a dual-harmonic generator generates a dual-band signal containing a fundamental frequency and a second harmonic, and the dual-band signal is radiated through the antenna; in the receiving mode, the double-harmonic generator is multiplexed as a frequency mixer, and echo signals received by the antenna are down-converted into intermediate-frequency signals to be output. According to the invention, the amplitude of the dual-frequency signal is balanced through the controllable asymmetric bias design, and the modulation bandwidth is equivalently expanded through the digital domain synthesis intermediate frequency signal. The problems that a traditional dual-frequency system is large in chip area and high in cost and a single-frequency system is low in resolution are solved, and the system has the advantages of being high in integration level, low in cost and high in resolution.
Owner:SOUTH CHINA UNIV OF TECH

Trigger based null data packet transmission method and related apparatus

A trigger based null data packet transmission method and a related apparatus are provided, which relate to wireless communication, and are applied to a wireless local area network supporting an 802.11be standard. The method includes: receiving, by an EHT station, an NFRP trigger frame; determining whether a resource for scheduling the EHT station is in an EHT modulation bandwidth or an HE modulation bandwidth based on information in the NFRP trigger frame; and sending an EHT TB NDP if the resource is in the EHT modulation bandwidth; or sending an HE TB NDP if the resource is in the HE modulation bandwidth, where the NFRP trigger frame includes a first user information field, and is used to schedule the EHT station to send the HE TB NDP in the HE modulation bandwidth and send the EHT TB NDP in the EHT modulation bandwidth.
Owner:HUAWEI TECH CO LTD

An FP cavity electro-optic modulator array usable in a multi-wavelength channel transmitter

The application discloses an FP cavity electro-optic modulator array which can be used for a multi-wavelength channel transmitter. The modulator array is mainly formed by sequentially connecting N modulator units; a single modulator unit comprises a 2*2 Fabry-Perot cavity structure, a substrate and a pair of modulation electrodes, the 2*2 Fabry-Perot cavity structure and the modulation electrodes are arranged on the upper surface of the substrate, the two modulation electrodes are symmetrically distributed on the two sides of the 2*2 Fabry-Perot cavity structure, the multiplexing end of a first mode demultiplexer is connected with the input end of an anti-symmetrical multimode waveguide grating, the two anti-symmetrical multimode waveguide gratings are connected through an intermediate waveguide, and the output end of the other anti-symmetrical multimode waveguide grating is connected with the multiplexing end of the first mode demultiplexer. The application has the advantages of compact structure, excellent electro-optic modulation performance of the modulator unit, large modulation bandwidth, flexible cascade mode, can be used for the multi-wavelength channel transmitter, and is suitable for being applied to large-capacity optical communication, optical calculation and the like.
Owner:ZHEJIANG UNIV

High-modulation-bandwidth high-heat-dissipation mini deep ultraviolet LED and preparation method thereof

The application provides a high-modulation-bandwidth high-heat-dissipation MINI deep ultraviolet LED and a preparation method thereof. The LED comprises, in sequence, a buffer layer, a distributed Bragg reflector structure, an epitaxial structure, a p-type electrode and a filling metal layer, which are sequentially grown on a substrate. The substrate is thinned and etched to form a plurality of columnar through holes. The filling metal layer has a platform and a plurality of metal columns distributed on the platform. The metal columns are located in the columnar through holes. The distributed Bragg reflector structure is used to increase the light emission efficiency. The lattice-matched multi-quantum well layer is used to effectively reduce the quantum confinement Stark effect, increase the internal quantum efficiency, and greatly improve the reliability and stability of the product. The device obtained by the preparation method has higher crystal quality, more uniform light emission, better heat dissipation performance, smaller time constant and smaller carrier lifetime due to the small size of the device, improved modulation bandwidth, and enhanced application in solar-blind ultraviolet communication.
Owner:SOUTH CHINA NORMAL UNIV

A high-speed external modulation laser chip and a preparation method thereof

The application relates to the field of optical communication, in particular to a high-speed external modulation laser chip and a preparation method, the chip comprising a modulator module and a laser module on the same substrate and the same first cladding layer, the laser module comprising a first confinement layer, a first multiple quantum well structure and a second confinement layer; the modulator module comprising a third confinement layer, a second multiple quantum well structure and a fourth confinement layer; the first confinement layer is butted with the third confinement layer, the first multiple quantum well structure is butted with the second multiple quantum well structure, and the second confinement layer is butted with the fourth confinement layer; a diffusion barrier layer is buried around the first multiple quantum well structure and the second multiple quantum well structure. The diffusion barrier layer is buried around the multiple quantum well structure of the chip, the diffusion barrier layer can effectively prevent the diffusion of Zn, reduce the leakage current, and improve the modulation bandwidth of the chip.
Owner:ACCELINK TECHNOLOGIES CO LTD

A dynamic absolute distance measurement method based on sinusoidal frequency modulation interference

The application relates to a dynamic absolute distance measurement method based on sinusoidal frequency modulation interference and relates to the field of laser radar phase demodulation technology. The application is aimed at solving the problems of low precision and limited measurement range of the existing absolute distance measurement method. The dynamic absolute distance measurement method based on sinusoidal frequency modulation interference comprises the following steps: inputting light signals emitted by a sweep frequency light source into a first coupler, so that the light signals are divided into two light signals; inputting the two light signals into a measurement interferometer and an auxiliary interferometer respectively; compensating the asymmetry of output signals by using an ellipse fitting algorithm; extracting the phases of the measurement interferometer and the auxiliary interferometer signals with high precision by using an inverse tangent and unwrapping operation; filtering the phase of the measurement interferometer; directly calculating the relative displacement of a target by using the low-frequency part; calculating the envelope of the signal by using the high-frequency part; calculating the envelope of the phase of the auxiliary interferometer; and finally calculating the absolute distance of the target by taking the ratio of the two envelopes and eliminating the influence of modulation bandwidth fluctuation.
Owner:HARBIN INST OF TECH

Low-complexity amplitude error correction in a wireless communication circuit

Low-complexity amplitude and phase (AM-PM) error correction in a transceiver circuit is provided. In embodiments disclosed herein, a transceiver circuit is configured to equalize an input vector to thereby correct an AM-AM error across a modulation bandwidth of the wireless communication circuit. Unlike conventional methods where complicated memory digital predistortion (mDPD) coefficients must be defined and calibrated for each modulation frequency within the modulation bandwidth, the transceiver circuit is configured herein to eliminate modulation frequency dependency of the AM-AM error. As a result, it is possible to correct the AM-AM error across the modulation bandwidth with reduced complexity to thereby improve efficiency and linearity of the wireless communication circuit.
Owner:QORVO US INC

Optical amplification system

Title: Optical Amplification System The invention relates to an optical amplification system (100), comprising: a semiconductor optical amplifier (1) configured to allow, under predetermined operating conditions, the appearance of amplitude gain ripples (deltaG) greater than 1 dB, in particular greater than 2 dB or 3 dB, the optical amplifier being configured to amplify a probe signal to at least one wavelength chosen within a period of the gain ripple to allow a modulation bandwidth of the probe signal by the optical amplifier that is greater than or equal to 5 GHz, in particular being substantially equal to 10 GHz. Figure for the abstract: Fig. 1
Owner:LAIR LIQUIDE SA POUR LETUDE & LEXPLOITATION DES PROCEDES GEORGES CLAUDE +1

Mach-Zehnder modulator based on silicon carbide substrate and preparation method thereof

The invention provides a Mach-Zehnder modulator based on a silicon carbide substrate and a preparation method of the Mach-Zehnder modulator. An isolation layer, a waveguide material layer, a Mach-Zehnder structure, a distributed traveling wave electrode and an upper cladding are sequentially formed on the silicon carbide substrate; by utilizing the characteristics that the silicon carbide substrate has low dielectric loss and a dielectric constant capable of being matched with the optical group refractive index in a high-frequency band and optimizing parameters of the distributed traveling wave electrode, the loss of a microwave signal in transmission can be remarkably reduced, and accurate matching of the microwave phase refractive index and the optical group refractive index can be realized; in addition, the heat conductivity coefficient of the silicon carbide substrate is far higher than that of a substrate material such as silicon, so that heat generated by working of a device can be effectively dissipated, interference of a heat effect on modulation performance is avoided, and further, the modulation bandwidth and the modulation efficiency of the Mach-Zehnder modulator are improved. According to the preparation process, the process stability and repeatability are remarkably improved, and feasibility is provided for large-scale integrated manufacturing of devices.
Owner:SHANGHAI INST OF MICROSYSTEM & INFORMATION TECH CHINESE ACAD OF SCI

A broadband and efficient acousto-optic modulator in shear wave mode and a preparation method thereof

The application discloses a wideband and high-efficiency acousto-optic modulator in a shear wave mode and a preparation method thereof, and relates to the technical field of integrated optics. The acousto-optic modulator comprises, from bottom to top, a silicon substrate, a silicon dioxide layer and a lithium niobate-chalcogenide glass hetero layer. The lithium niobate-chalcogenide glass hetero layer comprises a lithium niobate thin film, a chalcogenide optical waveguide, an interdigital transducer and a reflection grating which are hetero-integrated on the lithium niobate thin film. The reflection gratings are symmetrically arranged about the interdigital transducer, and an oblique included angle is formed between the interdigital transducer and the chalcogenide optical waveguide. The acousto-optic modulator comprehensively utilizes the excellent acousto-optic characteristics of chalcogenide glass materials, the outstanding piezoelectric effect of the lithium niobate thin film and the oblique included angle arrangement of the interdigital transducer relative to the optical waveguide. The mechanical deformation of the horizontal shear wave in the acoustic aperture direction is fully utilized, the reflection grating is used for the enhancement of the acoustic wave, the Q value of the acoustic wave resonant cavity is improved, the modulation bandwidth is improved, and the problem of low acousto-optic modulation efficiency is solved.
Owner:INTERNATIONAL INSTITUTE FOR INNOVATIVE DESIGN & INTELLIGENT MANUFACTURING OF TIANJIN UNIVERSITY-ZHEJIANG +1