5364results about "Laser details" patented technology

Tailored doping of barrier layers enables balancing of the radiative recombination among the multiple-quantum-wells in III-Nitride light-emitting diodes. This tailored doping enables more symmetric carrier transport and uniform carrier distribution which help to reduce electron leakage and thus reduce the efficiency droop in high-power III-Nitride LEDs. Mitigation of the efficiency droop in III-Nitride LEDs may enable the pervasive market penetration of solid-state-lighting technologies in high-power lighting and illumination.

A pest control system is disclosed comprising an optical, computational, and monitoring subsystem, optionally mounted on a mobile platform. The optical system may include a neutralizing laser or multi-wavelength light source, discovery and detail cameras (optionally stereo), a beam-steering mechanism, tunable focus, and optional thermal or depth sensors. The processor, such as a GPU or FPGA, identifies insect or biological targets, adjusts laser focus by depth, and controls beam activation. A monitoring system verifies safety by detecting humans or other non-target entities using environmental and thermal cameras; if detected, laser firing is inhibited. The mobile platform may use wheels, propellers, tracks, or cables, with GPS and data links for remote control. A visible light pre-flash may induce a blink reflex before firing. In some embodiments, a scouting drone transmits target coordinates to the neutralization unit, enabling coordinated, efficient, and safe laser-based pest control.

The invention discloses a temperature control and noise reduction method for an analog optical module, and relates to the technical field of data processing. The method comprises the following steps: collecting and preprocessing an original temperature signal, environment temperature time sequence data and an optical wavelength original detection value of an optical module; improving the LSTM model, constructing a junction temperature dynamic prediction model, and outputting prediction data; a pre-trained BP neural network is utilized to calculate the temperature compensation amount according to the real-time wavelength offset, and a PPO reinforcement learning algorithm is adopted to optimize with the temperature stability, the wavelength offset and the TEC power consumption as multiple targets to obtain an optimal PID parameter mapping table; and finally, predicting, compensating and optimizing parameters are fused, and control output for driving the TEC is generated through a multi-mode intelligent decision. The problems of insufficient control precision and response lag are effectively solved, cooperative high-precision control over the junction temperature and the emission wavelength of the laser is achieved, transmission noise is remarkably reduced, and meanwhile system energy consumption and the self-adaptive capacity are considered.

The invention relates to a light spot uniformity optimization method and system for a high-precision VCSEL device, and the method comprises the following steps: carrying out the light field collection of a light-emitting surface of the VCSEL device, obtaining the intensity distribution of original light spots, analyzing the non-uniformity of each light-emitting unit, and extracting the non-uniformity characteristics of the light spots. And carrying out deviation cause analysis based on the characteristics, and identifying device structure deviation parameters. According to the method, an etching process is optimized, a corrected oxidized aperture configuration scheme is obtained, near-field light field simulation is carried out by adopting a finite difference time domain method, and optimized light field distribution is verified and predicted. And finally, adaptive compensation design is carried out on the Bragg reflector structure based on a prediction result, light field regulation and control are realized, target light spot uniformity distribution is finally obtained, and the problem that systematic analysis and feedback control on non-uniformity causes of a light emitting unit layer in a device are lacked in the prior art is solved. And local bright spots or dark areas are caused.

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 discloses a laser frequency stabilization system based on Faraday anomalous dispersion atomic filtering, which is used for carrying out frequency stabilization on phase modulation multi-sideband laser, and comprises a frequency doubling laser unit which is configured to comprise a fundamental frequency seed light source, an electro-optical modulator, a fundamental frequency amplifier and a frequency doubling crystal; the light splitting module unit is configured to split the frequency doubling light into a main output light path and a monitoring light path; the atomic optical rotation filter is located on the monitoring light path and is configured to maintain the purity of the frequency-stabilized laser spectrum through purification treatment under the control of the axial magnetic field and the temperature; the frequency stabilization unit is configured to be a frequency stabilization light path and a servo system, and the frequency stabilization light path is used for obtaining laser frequency information and generating an error signal; the servo system is used for controlling the frequency of the fundamental frequency seed light source according to the error signal feedback. According to the laser frequency stabilization system provided by the invention, the spectrum purification and frequency stabilization precision can be improved, so that high-frequency stability locking is realized.

The invention provides a patterned photonic crystal laser and a preparation method thereof, the laser comprises a substrate, and a first mask layer, a photonic crystal layer and a second mask layer which are sequentially deposited on the substrate, a light emitting area is etched in the central area of the second mask layer, and transparent conductive layers are deposited on the surface of the second mask layer and the light emitting area; a p-annular electrode is arranged on the surface of the transparent conductive layer on the second mask layer, and an n-annular electrode is arranged below the substrate; the photonic crystal layer is composed of a nanorod array and a polymer filled in gaps of nanorods; holes distributed in a patterned array are etched in the surface of the first mask layer, and nanorods are epitaxially grown in hole areas; the nanorod is formed by sequentially depositing a substrate contact layer, a first waveguide layer, a multi-quantum well layer, a second waveguide layer, a coating layer and a component gradient layer. According to the invention, through collaborative design optimization of all the layers, emission of laser with specific wavelength and preparation of a laser emitting laser with single longitudinal mode, narrow linewidth and stable wavelength are realized.

The invention relates to the technical field of data processing, in particular to a real-time data monitoring and early warning method for the growth process of a VCSEL epitaxial wafer, which comprises the following steps: acquiring the refractive index of a material used by the epitaxial wafer at the current moment in the growth process of the VCSEL epitaxial wafer by using MOCVD (Metal Organic Chemical Vapor Deposition) equipment; determining the growth rate of the epitaxial wafer at the current moment; determining the mutation degree of the growth rate of the epitaxial wafer at the current moment; determining the correction mutation degree of the growth rate of the epitaxial wafer at the current moment; determining an early warning threshold value at the current moment; and monitoring and early warning of real-time data in the growth process of the VCSEL epitaxial wafer are realized according to the corrected mutation degree and the early warning threshold value. According to the method, accurate inversion of the growth rate and intelligent identification of mutation are realized, abnormal and normal process changes are effectively distinguished, the early warning threshold is adaptively adjusted, the false alarm rate is reduced, and the accuracy and practicability of VCSEL epitaxial growth monitoring are improved.

The invention relates to a method for improving epitaxial growth quality of a tunnel junction cascade semiconductor laser. The invention innovatively provides a strain superlattice gradient repair technology. By designing a low-temperature low-speed nucleation-high-temperature high-speed epitaxy composite growth mode, a periodic superlattice buffer layer is introduced to a tunnel junction interface. Wherein lattice strain relaxation is achieved at the rate of 0.5-2 / s in the low-temperature stage, defect coverage is completed at the rate of 4-8 / s in the high-temperature stage, and dislocation line bending is terminated on a superlattice interface through thermodynamic regulation and control. Compared with the traditional process, the scheme can obviously improve the crystal quality, and does not increase the specific contact resistance of the tunnel junction interface.

The invention relates to the technical field of fiber laser rapid interlocking protection scheme design, in particular to a fiber laser rapid interlocking protection circuit, and aims to solve the problems of long protection delay and low reliability of an MOPA structure laser in an abnormal state. The circuit comprises an interlocking protection bus, an interlocking control circuit and a multi-stage interlocking switch circuit. When an abnormity occurs, the interlocking control circuit detects a signal and triggers the switch circuit to quickly respond through bus level change: the main amplification stage LD is immediately turned off by the main amplification interlocking switch circuit, and the pre-amplification stage LD is sequentially turned off after the pre-amplification interlocking switch circuit delays. Therefore, sub-millisecond protection is realized, the working time sequence of the laser is strictly followed, and damage expansion is avoided. The circuit is integrated in the laser without depending on an external system, so that the reliability is improved and the structure is simplified. The method is suitable for various fiber lasers, and effectively prevents burning failure.

The invention relates to the technical field of laser, and provides a laser system with a controllable pulse state and a control method thereof. The control method of the laser system with the controllable pulse state comprises the steps that under the conditions that the cavity length of an FP cavity is in an initial fit state and the air pressure in the FP cavity is standard air pressure, a pump light source is controlled to adjust the pump power according to a first set; in response to the fact that the target pulse interval is smaller than the initial pulse interval, the pump light source is controlled to keep the target power unchanged, the air pressure of the FP cavity is adjusted to be within the preset range, and the cavity length of the FP cavity is adjusted through a second set; determining a target cavity length; controlling the laser to be output in a first pulse state; and controlling the laser to output in a second pulse state. According to the control method, the controllably generated abnormal wave form with the high peak power is introduced according to the preset frame structure to serve as a physical layer disturbance or random segment, and the reliability and safety of system signal transmission are improved under the condition that data segment transmission is not affected.

The invention discloses an on-chip time-frequency transmission system and method based on an octave optical comb and an electro-optical modulation optical comb, and the method comprises the steps: constructing a chip-based optical reference cavity through the technologies of vacuum optical cement, photoresist backflow and the like, and achieving an on-chip ultra-stable laser through a phase modulator and a reflection separation optical path; an on-chip laser source pumping micro-ring resonant cavity is utilized to generate an octave optical frequency comb, frequency multiplication is carried out on the on-chip laser source pumping micro-ring resonant cavity and an additional laser source to realize detection and locking of carrier envelope offset frequency (fceo), frequency beating is carried out on the on-chip laser source pumping micro-ring resonant cavity and the on-chip ultra-stable laser device to realize frequency beating (fbeam) locking, and the laser source is utilized to generate an electro-optical modulation optical frequency comb through a circulating phase modulator to realize frequency beating and locking of the on-chip ultra-stable laser device. And the optical time frequency is locked with the locked octave optical comb, is sent to a far end after polarization control and light amplification, and simultaneously receives an electro-optical modulation optical comb at the far end and performs linear light sampling, so that the transmission of the optical time frequency is realized. The optical fiber or space optical link time-frequency transmission device can realize optical fiber or space optical link time-frequency transmission, and has the advantages of low overall noise, high transmission precision, compact structure, small size, low power consumption and the like.

The invention discloses a low-divergence-angle narrow-linewidth high-power semiconductor laser. Relates to the technical field of semiconductor lasers, in particular to a low-divergence-angle narrow-linewidth high-power semiconductor laser. According to the invention, the parabolic waveguide structure is etched in the light field expansion area, and the metal reflector is introduced to realize a novel light field expansion and metal reflector integrated structure, and the transverse divergence angle of a laser mode is reduced through the expansion structure at the tail end of the waveguide. The laser comprises a laser gain area, a light field expansion area and a spectrum purification area at the tail of the light field expansion area. The laser gain region, the light field expansion region and the spectrum purification region at the tail part of the light field expansion region are made of the same laser epitaxial material in the longitudinal direction, the laser gain region is adjacent to the light field expansion region along the horizontal light emitting direction, and the light field expansion region is adjacent to the spectrum purification region at the tail part of the light field expansion region along the horizontal light emitting direction; the longitudinal direction is the direction from the substrate to the contact layer.

The invention provides a tunable laser source output wavelength adjusting device and method, and the method comprises the steps: starting a tunable laser source, carrying out the preheating, and resetting a motor motion unit; acquiring an initial light-emitting wavelength based on a pre-stored relation curve between the light-emitting wavelength of the laser source and the position of the motor; controlling the output wavelength of the laser source through the coarse tuning parameter of the motor motion unit, traversing the tunable output range of the tunable laser source, and collecting the wavelength position of the reflection peak value of the fiber bragg grating and the corresponding optical power value; according to the reflection peak wavelength position, through voltage regulation and control of stacked piezoelectric ceramics, step scanning is carried out according to a target wavelength, and a laser source output wavelength is dynamically adjusted to obtain a fine scanning wavelength; and judging whether the deviation between the fine scanning wavelength and the target wavelength meets the preset precision or not, if so, locking the output wavelength, otherwise, repeatedly regulating and controlling until the conditions are met. According to the invention, traditional current-wavelength dependence is broken through, and wavelength demodulation is realized through electromechanical collaborative calibration and two-stage scanning.

The invention relates to the technical field of chip preparation, and provides a chip based on an annular photonic crystal and a preparation method thereof. The preparation method comprises the following steps: growing a nucleating layer on a substrate; growing a superlattice structure on one side, away from the substrate, of the nucleating layer; sequentially growing an n-type coating layer, an n-type waveguide layer, a quantum well and a p-type electron blocking layer on one side, deviating from the nucleating layer, of the superlattice structure; etching a plurality of annular cavities on the p-type electron barrier layer to form an annular photonic crystal; growing a p-type extension contact layer on one side, deviating from the quantum well, of the p-type electron blocking layer; and carrying out in-situ annealing treatment. According to the preparation method, the directivity of the photonic band gap can be effectively adjusted, uniform light waves in all directions on the side face can be formed, so that leakage of laser from a non-light-emitting area on the side face is restrained, the light emitting efficiency is improved, the annular photonic crystals are periodically distributed, and the light beam quality is effectively guaranteed.

A chip-scale mode-locked laser including a cavity including a gain medium for amplifying signal electromagnetic radiation (signal) through stimulated emission, the signal comprising a signal wavelength; and a passive or active mode-locking device to enforce pulse formation in the laser. The mode-locking device includes a thin-film waveguide having a thickness on the order of the signal wavelength so as to confine and guide the signal along the thin-film waveguide, and a material comprising a second-order nonlinear susceptibility to enable active or passive mode-locking of the signal. The mode-locking device leads to generation of pulses of the signal outputted from the mode-locked laser.

The invention provides a well drilling anti-interference communication system based on a VCSEL (Vertical Cavity Surface Emitting Laser), the VCSEL and a manufacturing method thereof, and the manufacturing method comprises the following steps: calculating the light field intensity distribution of a high-order transverse mode through an intrinsic mode expansion method and a Laguerre-Gaussian model based on the epitaxial structure parameters of a laser; determining a target area which begins to perform downward annular etching on the surface of the p-DBR layer, wherein the target area coincides with a light field intensity peak area of the high-order transverse mode; performing annular etching in the target area to form an annular groove, and etching at least seven pairs of p-DBR layers inwards in the groove; the communication system comprises a signal transmitting end arranged on the derrick side, and the signal transmitting end is provided with the vertical cavity surface emitting laser; the p-DBR region of the vertical cavity surface emitting laser is provided with an annular etching structure; the graded-index fluorinated plastic optical fiber is used as a transmission medium and is connected with the derrick side and the logging room side; and the optical signal receiving end is arranged at the logging room side and is used for receiving and converting the optical signal into an electric signal.

A self-calibrating driver circuit (100, 300, 400, 500, 700) for a laser diode is disclosed. The circuit comprises a configurable current source (105, 305, 405, 505), a current mirror (115, 315, 415) configured to mirror a current from the configurable current source to a first transistor (120, 320, 420, 520, 720) and to a second transistor (125, 325, 425, 725), and a control circuit (140, 340, 440). The control circuit is configured to monitor a current through the first transistor at a first time, and to configure the current source based on the current through the first transistor to provide a desired current to the second transistor for driving the laser diode at a subsequent second time. A radiation-emitting device comprising one or more of the self-calibrating driver circuits and at least one radiation-emitting element is also disclosed.

Performance evaluation and structural optimization methods for a high-power semiconductor laser chip, and a performance evaluation system for a high-power semiconductor laser chip. The performance evaluation method for a high-power semiconductor laser chip comprises: providing a window on an N-side electrode of a chip to be tested (step 1); keeping the chip in an operating state (step 2); allowing a quantum well active region of the chip to generate spontaneous emission, so that the spontaneous emission is imaged outside the chip (step 3); acquiring, by means of a spectrograph, a spectrum of the spontaneous emission outside the chip and obtaining a two-dimensional distribution of a quantum well temperature of the chip in the operating state; and acquiring, by means of a CCD camera, an image of the spontaneous emission imaging outside the chip and obtaining a two-dimensional distribution of charge carriers in the quantum well of the chip in the operating state (step 4). According to the performance evaluation and structural optimization methods for a high-power semiconductor laser chip, the distributions of the temperature and the charge carrier concentration in the quantum well of the chip to be tested in the operating state in which the resolution is freely adjusted can be obtained. Operations of the methods are convenient, and implementation is simple and easy, thereby efficiently improving the accuracy of an evaluation result.

A hybrid silicon photonic integrated circuit (48) for an FMCW LIDAR device (14), comprises a first SOI substrate (70) having a trench (80), a first optical waveguide (76) monolithically formed on or in the first SOI substrate (70) and abutting the trench (80), and a heterogeneously integrated laser chip (50) received upside down in the trench (80). A free-space coupler (36) is monolithically formed on or in the first SOI substrate (70), connected to the laser chip (50) via the first optical waveguide (76) and emits the light generated by the laser chip (50) into free space. A detector (32) is detects a superposition of reflected light, which was emitted by the free-space coupler (36) and reflected at an object (12) to which a range shall be measured, and reference light, which was not reflected at the object (12).

The invention relates to the technical field of lasers, in particular to a multi-chip vertical external cavity surface emitting laser which comprises a chip set, a first prism, a second prism and an output coupling mirror which are sequentially arranged along a preset central axis. The chipset comprises N gain chips, and the N gain chips output N sub light beams; the N sub-beams pass through the first prism, the sub-beams emitted from the first prism converge towards a preset central axis, the sub-beams are incident to the second prism before convergence and are combined into a resonant beam through the second prism, the resonant beam resonates in a resonant cavity formed by the output coupling mirror and the chip set, and the output coupling mirror and the chip set form a resonant cavity; the output laser is emitted from the output coupling mirror; wherein N is greater than 1. The invention is beneficial for solving the problems that the power of a single chip is limited, the beam combining efficiency is low, only incoherent beam combining can be realized, and a multi-chip beam combining structure is complex.

The invention discloses a semiconductor narrow linewidth laser temperature cycle test system and a test method thereof, which belong to the field of laser communication and eliminate errors caused by system loss to optical power measurement through optical power calibration compensation coefficients. The variable-temperature adjustment is controllable, the wavelength of the laser is efficiently tuned, and various indexes are measured. The device mainly comprises a plurality of drivers and a high-low temperature test box, to-be-tested laser parts of a plurality of tested lasers are placed in the high-low temperature test box, and other parts of the tested lasers are located outside the high-low temperature test box so as to avoid the influence of equipment temperature drift on measurement; the plurality of drivers are respectively and correspondingly connected with the plurality of tested lasers, optical chip driving current and TEC closed-loop temperature control are provided for the tested lasers, wavelength tuning of the lasers is realized through the TEC closed-loop temperature control system, and temperature sensors are arranged at the tested lasers in the high and low temperature test box. The invention is mainly used for the semiconductor narrow linewidth laser temperature cycle test system.

The invention relates to the technical field of semiconductor lasers, in particular to a vertical-cavity surface-emitting semiconductor laser and a manufacturing method thereof.The vertical-cavity surface-emitting semiconductor laser comprises a substrate, an N-type DBR layer, an active region, an oxide layer, a P-type DBR layer, a P contact layer and a P metal layer which are sequentially arranged from bottom to top, oxidation holes are formed in the oxide layer, a carbon displacement modulation structure layer is arranged in the P contact layer, and the P metal layer is arranged in the N-type DBR layer. The lower end of the carbon displacement modulation structure layer is located in the P-type DBR layer, the carbon displacement modulation structure layer is right opposite to the oxidation hole, and the material of the carbon displacement modulation structure layer is GaAs doped with carbon atoms. The high-frequency characteristic, single-mode performance, ultra-long service life, wide-temperature work and extreme environment resistance which are difficult to reach by a traditional pure oxidation limiting scheme and a traditional diffusion technology and oxidation limiting VCSEL scheme are achieved through cooperation of precise control of the SEG technology and the ultra-low diffusion characteristic of carbon.

The invention relates to the technical field of semiconductor lasers, in particular to an ultra-narrow linewidth wavelength-adjustable external cavity laser based on a planar metal grating, which comprises a gain chip, and the left end face and the right end face of the gain chip are respectively plated with a high reflection film and a first antireflection film; a planar metal grating waveguide is arranged on the right side of the gain chip, the right end face of the gain chip is aligned and attached to the left end face of the planar metal grating waveguide, and a second antireflection film and a third antireflection film are plated on the left end face and the right end face of the planar metal grating waveguide respectively; the planar metal grating waveguide comprises a grating waveguide substrate, a ridge optical waveguide is arranged on the upper portion of the grating waveguide substrate, an annular resonance optical waveguide is arranged on the front side of the ridge optical waveguide, a planar metal grating is arranged on the upper portion of the ridge optical waveguide, and a top covering layer is arranged on the upper portion of the planar metal grating. Through the centimeter-level metal grating and the low-loss coupling structure, light beam quality with 3dB line width less than 700Hz and M2 less than 0.9 is realized.

The invention relates to the technical field of semiconductors, in particular to a semiconductor laser and a processing method thereof.The semiconductor laser comprises a mounting frame, a bottom plate, a top plate, an electrode plate and a plurality of laser stacking assemblies, and each laser stacking assembly comprises a first laser unit and a second laser unit; the first laser unit comprises a first laser body, a first supporting plate and a first bottom plate; the second laser unit comprises a second laser body, a second supporting plate and a second top plate, the second supporting plate is provided with a second liquid inlet and a second flow passing channel, the second liquid inlet is communicated with the first liquid outlet, the second top plate is fixed to the top of the second supporting plate, a second liquid outlet is formed, and the second liquid outlet and the first liquid inlet are located on the same axis. A plurality of laser stacking assemblies can be connected in sequence, heat dissipation is carried out in a series connection mode, and therefore the heat dissipation capacity of the laser stacking assemblies is greatly improved.

The invention provides a semiconductor laser chip and a preparation method, and belongs to the technical field of semiconductor laser chip preparation, and the semiconductor laser chip comprises an N-surface metal, a substrate, an N-type limiting layer, an N-type waveguide layer, a tensile strain quantum well, a P-type waveguide layer, a P-type limiting layer, an ohmic contact layer, a SiO2 insulating layer, a first P-surface metal layer and a second P-surface metal layer which are sequentially arranged from bottom to top. Waveguide grooves are symmetrically formed in the two sides of the ohmic contact layer and penetrate through the ohmic contact layer, the bottoms of the grooves sink to the P-type limiting layer but do not exceed the P-type limiting layer, and a ridge waveguide is formed between the two grooves. The depth of the waveguide groove is of a stepped structure in the longitudinal direction, the depth of the area close to the cavity surface is increased to the N-type waveguide layer, the area completely covers the SiO2 insulating layer and the first layer of P-surface metal, but no second layer of P-surface metal exists, and the longitudinal stepped structure is formed. Through the design of the tensile strain quantum well and the stepped waveguide groove, cavity surface tensile strain release is realized, light absorption is reduced, and the reliability and the service life of the chip are improved.

The classical channel employs a transmit laser and classical modulator. The quantum channel employs a nonlinear medium and spontaneous parametric down conversion producing quantum entangled signal and idler photon pairs which are encoded. The classical and quantum channels are combined to define a propagated hybrid signal. The receiver splits the hybrid signal on basis of wavelength into classical and quantum channels. The quantum receiver employs optical parametric amplification, supplied with energy from a second harmonic generation device synchronized to the classical carrier wavelength. A photodetector and extracts a quantum message from the quantum signal.

The invention belongs to the technical field of radiation effect and radiation hardening of semiconductor devices and integrated circuits, and particularly relates to a single event effect laser simulation system based on Bessel beam shaping. A Bessel beam shaping and focusing module based on an axon lens is introduced and composed of the axon lens and two lenses, namely a single lens and a focusing lens, a Gaussian beam of an incident beam is shaped into a quasi-Bessel beam, and the quasi-Bessel beam is utilized to irradiate a semiconductor device to be detected. The axial distribution of the light beam is kept unchanged in a range of hundreds of microns, and the focusing breaking through the diffraction limit is realized in the radial distribution, so that the effect closer to the heavy ion charge deposition track is generated. The technology can solve the problem that a multilayer structure device, a thick sensitive region device and a wide forbidden band device are difficult to test through traditional laser simulation, and has important practical value for promoting laser simulation of the single event effect.

The invention belongs to the technical field of semiconductor device performance testing, and particularly relates to a VCSEL epitaxial wafer resistivity distribution measuring method and system, and the method comprises the steps: constructing a three-dimensional discretization model representing an epitaxial wafer and an unknown parameter vector containing the vertical resistivity, the top transverse resistivity and the substrate leakage junction nonlinear resistance; a physical response function is defined, the vector is iterated through a discrete point fitting algorithm, so that the total residual error between the analog voltage difference output by the function and the actually measured voltage value under the cross-order-of-magnitude current is minimum, and the real vertical resistivity is extracted from the optimal parameter vector; and obtaining the vertical resistivity of each point on the two-dimensional test point grid so as to generate a distribution diagram and carry out anomaly detection. According to the invention, the problem of measurement distortion caused by the leakage defect of the substrate is solved, and the measurement accuracy of the vertical resistivity is improved.

An optical comb generator receives light from at least two continuous wave laser sources, produces a different frequency comb from each laser source, and produces an output that it the simultaneous combination of the different frequency combs. The different frequency combs span different frequency bands, but at least partially overlap in frequency with an adjacent comb in a region of overlap. A spectral filter produces a filtered output that has at least one pair of tones from the region of overlap, the pair of tones comprising one tone from each of two adjacent combs. Feedback control based on the filtered output is applied to adjust the light entering the comb generator such that the frequencies and phases of the pair of tones from the region of overlap are aligned. In this way, the multiple different overlapping combs are stitched together to form a single seamless comb spanning a broader frequency range.