105 results about "Modulation bandwidth" patented technology

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.

The invention provides an electro-optical modulator combining a slow light waveguide and a capacitive load type traveling wave. The electro-optical modulator comprises the slow light waveguide, a capacitive load type traveling wave electrode, a multi-mode interferometer, a mixed single-mode waveguide, a micro-ring structure and a micro-ring upper phase adjusting electrode. Capacitive load type traveling wave electrodes are arranged between and on the side edges of a pair of slow light waveguides which are arranged in parallel, the two ends of the slow light waveguides are connected to one end of a multimode interferometer through mixed single-mode waveguides respectively, the other end of the multimode interferometer is provided with two ports, one port is used for being connected with a micro-ring structure, and the other port is used for being connected with a micro-ring structure. The other port is used as the input end or the output end of the electro-optical modulator, and the two sides of the micro-ring structure are provided with micro-ring upper phase adjusting electrodes. The group refractive index and the working bandwidth of light can be regulated and controlled by adjusting the geometric parameters of the slow light waveguide, and low dispersion and high group refractive index can be realized in a wide optical bandwidth range; through a sectional capacitance load type slow wave electrode structure, the regulation and control of the microwave refractive index are realized, and the electro-optical modulation bandwidth is improved.

The embodiment of the invention relates to a semiconductor laser, a light emitting assembly and an optical module. The semiconductor laser comprises a resonant cavity structure, the resonant cavity structure comprises a resonant cavity, the resonant cavity is used for generating standing waves, and the resonant cavity is limited by a bottom reflector structure and a top reflector structure; a multi-quantum well structure is arranged in the resonant cavity, and the multi-quantum well structure is arranged at the wave crest position of the resonant cavity; the thickness of the resonant cavity is designed to be smaller than three-second lasing wavelength so as to improve the relaxation oscillation frequency of the semiconductor laser. By applying the scheme of the invention, the relaxation oscillation frequency can be improved, and the modulation bandwidth of the device is improved.

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.

The invention discloses a novel FMCW laser radar signal processing method based on a lightweight neural network. The novel FMCW laser radar signal processing method comprises the steps of performing data preprocessing on an acquired non-stationary FMCW laser radar intermediate frequency signal by using variational mode decomposition; calculating the characteristic quantity of each group of components as an index for evaluating component characteristics, establishing a composite criterion factor for component selection according to different weights of the index, and screening out the component with the maximum criterion factor; designing a lightweight long-short-term memory neural network to carry out multi-step prediction on the screened component signals; fFT and CFAR algorithms are used to carry out frequency spectrum estimation and target detection on LSTM multi-step prediction results, and target distance information is calculated through an FMCW laser radar detection principle. Aiming at the problem of low detection precision of the FMCW laser radar under limited laser frequency modulation bandwidth and limited data length, the target distance information is extracted with lower cost and higher efficiency, so that the FMCW laser radar system has larger equivalent bandwidth, better distance measurement resolution and higher signal-to-noise ratio.

Amplitude and phase 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 amplitude-amplitude (AM-AM) and amplitude-phase (AM-PM) errors 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 and AM-PM errors. As a result, it is possible to correct the AM-AM and AM-PM errors across the modulation bandwidth with reduced complexity to thereby improve efficiency and linearity of the wireless communication circuit.

The invention provides a laser chip and a preparation method thereof. The laser chip comprises a light emitting region and an electric absorption modulation region. The electric absorption modulation area comprises a substrate, an active layer, a waveguide layer and a modulation electrode. The waveguide layer comprises a ridge structure, a first ridge groove and a second ridge groove, wherein the first ridge groove and the second ridge groove are located on two sides of the ridge structure. A first filling medium is arranged in the first ridge groove, and a second filling medium is arranged in the second ridge groove. The first filling medium and the second filling medium are both low-dielectric-constant media. One end of the modulation electrode is arranged on the surface of the ridge structure, and the other end is arranged on the surface of the first filling medium, namely the first filling medium is arranged between the modulation electrode and the laser chip. In the invention, when the first ridge groove and the second ridge groove are respectively filled with the low dielectric constant medium, the parasitic capacitance introduced when the modulation electrode covers along the two sides of the ridge structure can be reduced, and the dielectric loss is reduced, so that the influence of parasitic parameters on the modulation bandwidth of the laser chip is reduced, and the modulation bandwidth of the laser chip is improved.

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.

A multimode voltage tracker circuit is provided. The multimode voltage tracker circuit is configured to generate a modulated voltage for amplifying a radio frequency (RF) signal, and the RF signal can be modulated in a wide modulation bandwidth range. In one non-limiting example, the multimode voltage tracker circuit can be configured to operate in a low modulation bandwidth (LMB) mode to generate an average power tracking (APT) modulated voltage for amplifying the RF signal when the RF signal is modulated in a lower modulation bandwidth (e.g., <50KHz). Thus, the multimode voltage tracker circuit can be suitable for supporting lower bandwidth communications in Internet of Things (IoT) networks with improved efficiency, stability, and performance.

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.

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.

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.

The present invention discloses a semiconductor laser comprising: an N-face electrode; an N-type substrate disposed on the N-face electrode; and a whispering gallery microcavity disposed on the N-type substrate. The whispering gallery microcavity has an octagonal cross-section, comprising a plurality of first curved sides and at least one second curved side. The arc chords of the first and second curved sides are equal, while the arc lengths of adjacent first and second curved sides are unequal, thereby forming two independent sets of fully reflected quadrilateral optical paths within the whispering gallery microcavity. By adjusting the curvature of the curved sides of the whispering gallery microcavity, the wavelength spacing and lasing intensity of the two sets of modes can be further adjusted, significantly increasing the direct modulation bandwidth of the semiconductor laser while maintaining a side mode suppression ratio greater than 30dB.

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.

The present invention discloses a high-efficiency, ultra-wideband, low-insertion-loss Mach-Zehnder modulator, which belongs to the fields of microwave photonics, optoelectronic modulators, and high-efficiency optoelectronic conversion. The present invention comprises a SiO2 substrate, on which are disposed dual-parallel Mach-Zehnder modulators, each with a pattern spot converter at either end. Based on the process technology of lithium niobate thin film modulators, the present invention optimizes the pattern spot conversion waveguide structure, achieves low insertion loss, and increases the modulation bandwidth through dual-parallel modulators. The present invention can effectively improve the linearity and operating bandwidth of microwave photonic links, meeting the widespread application requirements of broadband satellite communications and high-frequency RF front-ends in various fields.

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.

The invention discloses a ZigBee backscattering method and system, electronic equipment and a storage medium, and relates to the technical field of backscattering communication. The method comprises the following steps: acquiring an excitation source signal; the excitation source signal comprises a plurality of uncontrolled environment signals; setting a phase shift symbol and a label modulation phase shift; and optimizing a modulation bandwidth based on the phase shift symbol, dividing the excitation source signal based on the tag modulation phase shift, determining a writable resource block and a non-writable resource block, and generating a ZigBee chip sequence according to the writable resource block. According to the invention, the uncontrolled environment signal is used as excitation, the generated ZigBee signal can be demodulated by a single commercial device through the backscattering label, and the universal deployment requirement in practical application is met.

The application discloses an optical module, comprising a silicon optical chip, the silicon optical chip comprising a silicon substrate, an optical coupler arranged on the silicon substrate, first and second input waveguides connected with the optical coupler, first and second coupling waveguides, a PN type doped region connected with the first and second coupling waveguides, a Ge absorption region connected with the PN type doped region, and a metal electrode arranged on the silicon substrate, the first coupling waveguide is connected with the first input waveguide, the second coupling waveguide is connected with the second input waveguide, the thickness size of the first and second coupling waveguides is smaller than that of the first and second input waveguides; the PN type doped region is arranged on the first and second coupling waveguides, the Ge absorption region is arranged above the PN doped region, the Ge absorption region is used for absorbing optical signals and converting the optical signals into electrical signals; the metal electrode is in contact with the PN type doped region and is used for transmitting the electrical signals. The application simultaneously realizes high modulation bandwidth and high optical responsivity through a special waveguide structure and a Ge detector design.

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.

An electronic device includes an N-way Doherty power amplifier with an amplifier input and an amplifier output, wherein N is an integer larger than or equal to two, a number of transformers for the Doherty output network, wherein the number of transformers is N-l; and a high-speed adaptive biasing circuit. A transmit / receive front-end module that integrates the N-way Doherty amplifier with a low-noise amplifier and a transmit / receive switch, occupying a compact area.

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.

An envelope tracking (ET) integrated circuit (ETIC) is provided. The ETIC is configured to generate an ET voltage for amplifying a radio frequency (RF) signal modulated for communication in multiple time intervals. In embodiments disclosed herein, the ETIC is self-contained to generate an ET target voltage based on a power envelope of the RF signal and to generate the ET voltage based on the ET target voltage. Given that the RF signal may be modulated at a very high modulation bandwidth, the ETIC can be configured to modify the ET target voltage in each of the time intervals to thereby cause the ET voltage to be adapted on a per time interval basis. As a result, the ET voltage can better track the power envelope of the RF signal in each of the time intervals to help improve operating efficiency of a power amplifier apparatus that employs the ETIC.

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.

A kind of based on Aulter-Townes effect and phase change material's cascade double-ring silicon light modulator structure, including a single-mode bus waveguide and two ring waveguides;Phase change material is integrated on the surface of ring waveguide to adjust the initial resonant wavelength of two micro-rings;PN junction is integrated in ring waveguide, and phase modulation to light is realized by carrier injection.Aulter-Townes effect is utilized to make micro-ring transmission spectrum form two split supermodes, and the extinction ratio corresponding to two supermodes is changed by adjusting the resonant wavelength of double micro-rings;Meanwhile, cascade double micro-ring structure can realize large modulation bandwidth, and meet the demand of high-speed transmission.Micro-ring waveguide deposits phase change material, and the resonant wavelength tuning has non-volatility, compared with traditional thermal tuning mode, can greatly reduce the regulation power consumption.The application overcomes the technical bottleneck of existing silicon light modulator, and can meet the practical application demand of high-extinction-ratio high-speed modulator in optical interconnection, optical communication and optical computing fields.

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.

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.

The invention provides a high-passband composite electro-optical modulator. The high-passband composite electro-optical modulator comprises a substrate, a buffer layer arranged on the substrate, an electro-optical material layer arranged on the buffer layer, an electrode layer arranged on the electro-optical material layer and a covering layer which is arranged on the electro-optical material layer and wraps the electrode layer. Wherein the electro-optical material layer comprises an electro-optical substrate arranged on the buffer layer and an electro-optical modulation layer integrally formed with the electro-optical substrate on the surface of the electro-optical substrate, and the electro-optical modulation layer comprises at least one grating coupling structure and an embedded strip-shaped waveguide arranged at an interval with the grating coupling structure; the electrode layer comprises two electrode plates which are arranged at intervals, and the two electrode plates are arranged on the electro-optical substrate and are distributed in a mirror symmetry mode relative to the central axis of the embedded strip-shaped waveguide. According to the high-passband composite electro-optical modulator provided by the invention, the high-efficiency coupling advantage of the grating, the low transmission loss characteristic of the embedded strip-shaped waveguide and the precise electric field regulation and control capability of the electrode layer are integrated, so that the transmission loss is reduced, and meanwhile, the modulation bandwidth is widened and the modulation depth is improved.

The invention discloses a semiconductor device structure which comprises a substrate and an epitaxial structure formed on the substrate through single epitaxy. The epitaxial structure comprises a P-type doped layer located at a bottom layer, an intrinsic doped layer comprising a multi-quantum well structure and an N-type doped layer located at a top layer which grow in sequence, and further comprises a continuous optical waveguide structure manufactured on the epitaxial structure. The first electro-absorption light modulator and the second electro-absorption light modulator are manufactured on the basis of the partial region of the optical waveguide. The double-section high-speed electro-absorption modulator suitable for differential driving is realized through an electrical isolation method based on ion implantation, and under the condition that the total length of active modulation is fixed, compared with a common single-section electro-absorption light modulator driven at a single end, the effective RC constant of the device can be reduced by half so as to improve the electro-optical modulation bandwidth, and the power consumption of the device is reduced. Therefore, a higher-speed optical transmission scene can be supported.

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.

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.