438 results about "External cavity" patented technology

The invention relates to the technical field of semiconductor lasers, in particular to a laser based on a bimetallic Bragg grating and a top surface HR reflecting film, which comprises a gain chip, a first high-reflection HR film is plated on the left end surface of the gain chip, and a first anti-reflection AR film is plated on the right end surface of the gain chip. A metal Bragg grating waveguide is arranged on the right side of the gain chip, the right end face of the gain chip and the left end face of the metal Bragg grating waveguide are aligned and attached to form an outer cavity structure, and the left end face of the metal Bragg grating waveguide is plated with a second anti-reflection AR film. The right end face of the metal Bragg grating waveguide is plated with a third anti-reflection AR film. Performance test is carried out on the laser provided by the invention, and test results show that the line width is 0.6 kHz, the SMSR is 63dB, and the threshold current is 22mA, thereby verifying the effectiveness of the laser provided by the invention.

The invention relates to the technical field of semiconductor lasers, in particular to a laser based on a bimetallic Bragg grating and a top SiO2 waveguide layer, which comprises a gain chip, the left end face of the gain chip is plated with a first high-reflection HR film, and the right end face of the gain chip is plated with a first anti-reflection AR film; a metal Bragg grating waveguide is arranged on the right side of the gain chip, the right end face of the gain chip and the left end face of the metal Bragg grating waveguide are aligned and attached to form an outer cavity structure, and the left end face of the metal Bragg grating waveguide is plated with a second anti-reflection AR film. The right end face of the metal Bragg grating waveguide is plated with a third anti-reflection AR film. According to the invention, a temperature change test is carried out, and the wavelength drift is controlled to be + / -0.002 nm in a range of-40 DEG C to 85 DEG C; performance test results show that the line width is 0.6 kHz, the SMSR is 65 dB, and the threshold current is 22 mA.

The invention discloses an external cavity tunable laser linewidth compression system for realizing wavelength phase locking based on mutual injection of gain chips. The external cavity tunable laser linewidth compression system comprises a red light semiconductor laser main gain chip, a first collimation optical system, a blazed grating, a tuning rotating mirror, a reflector, a power supply driving system and a double-path feedback amplification system, the double-path feedback amplification system comprises a first secondary gain chip, a second secondary gain chip, a second collimation optical system, a third collimation optical system and a polarization-free beam splitter prism; and the red light semiconductor laser main gain chip, the first secondary gain chip and the second secondary gain chip are all connected with the power supply driving system. Therefore, the technical problems of low output infrared light power, poor stability and narrow mode-hopping-free tuning range in the prior art are solved, and high-power, narrow-linewidth, high-stability and large-range mode-hopping-free continuous tuning red light output can be realized.

The invention relates to a semiconductor laser, in particular to a silicon-based hybrid integrated external cavity narrow-linewidth laser, which is used for solving the problems of poor integration, insufficient stability, high cost and the like in the existing narrow-linewidth laser technology. The silicon-based hybrid integrated external cavity narrow linewidth laser comprises a semiconductor gain chip, a silicon-based grating and a conical optical fiber. Wherein the semiconductor gain chip is coupled with the incident end face of the grating outer cavity, and the emergent end face of the grating outer cavity is directly coupled with the tapered fiber. By utilizing the grating outer cavity, the photon service life is prolonged, the output line width is narrowed, and the device has the advantages of being narrow in output line width, high in output power, high in process stability, small in size, integrated and the like.

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 provides a near-infrared perovskite laser without an external cavity and a preparation method thereof. The preparation method of the near-infrared perovskite laser without the external cavity comprises the following steps: dropwise adding a perovskite precursor solution on a substrate; covering a flexible thin film on the substrate, so that the perovskite precursor solution is uniformly distributed between the substrate and the flexible thin film; after the substrate is subjected to standing treatment, the flexible thin film is removed, the perovskite gain dielectric layer is obtained, the flexible thin film is used for inducing the perovskite precursor solution to grow a microcrystalline structure in the process of forming the perovskite gain dielectric layer, and the microcrystalline structure is a resonant cavity of the perovskite gain dielectric layer. According to the preparation method provided by the invention, high-temperature treatment such as heating or thermal annealing is not needed, the preparation process is simple, the cost is low, large-area preparation of the near-infrared perovskite laser without an external resonant cavity can be realized, and adjustment of the emission peak of the laser can be realized by regulating and controlling the components of the perovskite gain material and preparation process parameters.

The embodiment of the invention provides a silicon carbide crystal growth furnace and a silicon carbide crystal growth method, the silicon carbide crystal growth method is applied to the silicon carbide crystal growth furnace, and relates to the technical field of silicon carbide crystal growth. The silicon carbide crystal growth furnace comprises a crucible, a first flow guide cover, a second flow guide cover and a filtering piece, the growth atmosphere in the crucible can flow upwards along an external cavity formed by the wall surface of the crucible and the second flow guide cover, and after reaching the top, the growth atmosphere flows downwards along the inner wall of the second flow guide cover and the outer wall of the first flow guide cover and finally enters a crystal growth cavity formed by the first flow guide cover and the second flow guide cover; and a filtering piece is arranged between the first flow guide cover and the second flow guide cover. Therefore, the speed of the growth atmosphere can be ensured to be relatively uniform, the concentration of the growth atmosphere is improved, and the growth quality of silicon carbide crystals is improved.

The invention provides a 2-micron high-order Poincare sphere vector vortex ultrafast laser polarization detection method, which comprises the following steps of: performing out-cavity and out-cavity beam splitting on 2-micron high-order Poincare sphere vector vortex ultrafast laser through a beam splitting module, directly detecting light intensity spatial distribution by one beam, and dynamically regulating and controlling the out-cavity of a polarization state by the other beam after the other beam enters a polarization regulation and control module; the computer communicates with the ESP32 development board to control the hollow rotary displacement table to change the forward included angle between the fast axis and the x axis of the vortex quarter-wave plate so as to change the polarization state of incident light; through the ultrafast laser polarization beam splitter, the polarization state of passing light is limited, and horizontal line polarized light perpendicular to a beam splitting surface passes through the ultrafast laser polarization beam splitter; dynamically detecting real-time data of light intensity which is dynamically adjusted outside the cavity through the polarization regulation and control module each time through a light intensity detection module; and the polarization analysis module receives regulation and control parameters of the polarization regulation and control module and light intensity parameters of the power detection module, analyzes the polarization state of a light beam input into the system, and completes 2-micron high-order Poincare sphere vector vortex ultrafast laser polarization detection.

The present disclosure is applicable to a field of laser radar technology and provides a resonance module, a silicon-based external cavity chip, a laser, and a laser radar. The resonance module includes multiple main resonators and at least one auxiliary resonator, both of the main resonators and the auxiliary resonator are tunable micro-ring resonators; the multiple main resonators are cascaded in sequence through a connecting module to form a cascaded structure, and a vernier effect can be formed between two adjacent main resonators; when an auxiliary resonator is provided for matching the main resonator, coupling of the main resonator and the auxiliary resonator that are provided in a matching manner expands a free spectrum range of the main resonator. The tunable range of lasers applied to the laser radar and improve the scanning angle of the laser radar can be expanded.

The invention belongs to the technical field of quantum precision measurement, and particularly discloses a frequency stabilization system and a frequency stabilization method for an external cavity semiconductor laser. The system comprises a saturated absorption spectrum module, a wavelet peak searching module, a modulation and demodulation module, a bias amplification module and a switch module, wherein the saturated absorption spectrum module outputs an electric signal of a saturated absorption spectrum; under the control of the frequency locking instruction, the wavelet peak searching module outputs a target bias voltage signal corresponding to the locking frequency based on the electric signal; the modulation and demodulation module performs signal modulation and demodulation based on the electric signal and a reference signal corresponding to the locking frequency to output a modulation signal and a demodulation signal; and the bias amplification module performs superposition and amplification processing on the modulation signal, the demodulation signal and the target bias voltage signal, and outputs a target superposition signal to a PZT modulation port of the laser, so that the output laser freely operates on the locking frequency. According to the invention, the laser is not liable to generate mode hopping in the frequency locking process, the whole frequency stabilization system is more stable, the structure is simple, and the cost is low.

The invention belongs to the technical field of optical communication, and particularly relates to a narrow linewidth laser based on a cascaded micro-ring resonant cavity. The laser comprises a semiconductor laser inner cavity module, a gain chip module, a phase shifter, a cascade micro-ring resonant cavity module, a thermal tuning module and an outer cavity reflector. The gain chip is combined with an III-V group material at the top of the silicon waveguide through heterogeneous integration, and adopts an InAlGaAs quantum well to provide high gain; the phase shifter is used for matching the lasing wavelength with the resonant wavelength; the cascaded micro-ring resonant cavity is formed by cascading three micro-rings, and tuning of the laser is realized based on a vernier effect; the thermal tuning module is composed of three semi-annular metal strips and a straight waveguide-shaped metal strip. The outer cavity reflector module adopts a Sagnac ring structure; the laser inner cavity, the gain chip, the cascade micro-ring resonant cavity and the outer cavity reflector are directly connected through silicon waveguides. The laser has the characteristics of narrow linewidth and wide tuning range, is easy to highly integrate and interconnect, and has important application value.

The invention relates to a wavelength-switchable, semiconductor laser (10), for generating of laser light in the optical range between 1 μm and 100 μm, wherein the laser (10) comprises an external cavity (11) and at least the following components: a semiconductor optical amplifier (12), comprising an intra-cavity facet (121) facing towards; a first optical element (13) for collimating a laser beam exiting the intra-cavity facet (121) arranged at the intra-cavity facet (121) of the semiconductor optical amplifier (12); a transmissive, wavelength-adjustable interference filter (1), comprising at least i) a wavelength-adjustable Fabry-Perot filter (100) and ii) a Fabry-Perot etalon (110) comprising a first planar surface (111) and a second planar (112) surface, wherein the first and second surface (111, 112) of the etalon (110) are arranged opposite and plane-parallel to each other and delimit an etalon cavity (113); wherein the Fabry-Perot etalon (110) and the Fabry-Perot filter (100) are arranged in a row; wherein the interference filter (1) is arranged between the first optical element (13) and the beam splitter (14), and wherein the components are arranged such that laser light comprising a selected laser wavelength can stably resonate in the external cavity, wherein an on-axis, retro-reflecting beam splitter (14) is arranged at one end of the external cavity (11). Furthermore, the invention relates to a method for selecting a laser wavelength using the laser.

The invention relates to the technical field of optoelectronic devices, in particular to a laser based on two different gratings and a metal grating with a phase interval of lambda / 2, which comprises a gain chip, a gain chip optical waveguide, an optical waveguide substrate, an optical waveguide, an annular resonant optical waveguide and a metal BRAGG reflecting grating. A unique outer cavity structure is adopted, a traditional interlayer semiconductor grating is abandoned, a top metal grating is adopted, a traditional DFB sandwich type secondary epitaxy manufacturing process is greatly simplified and avoided, the production cost is reduced, particularly, the metal grating is divided into two parts with similar but different grating constants, and the phase positions of the two gratings are pulled by lambda / 2, so that the performance of the DFB is improved. According to the design, the side mode rejection ratio (SMSR) of laser beams can be effectively improved, the laser line width is compressed, a guarantee is provided for stable work of the laser in a high-performance application scene, and the grating reflection efficiency is effectively improved by combining a'mouth-to-mouth 'coupling butt joint mode of the gain chip and the optical waveguide substrate.

The present application relates to an external cavity narrow linewidth laser assembly, comprising: a substrate, to which a gain chip for emitting laser light is fixedly connected; a first light-transmitting reflector and a second light-transmitting reflector, spaced in sequence and located in the direction of the laser emitting end of the gain chip, are also connected to the substrate; the first light-transmitting reflector is spaced apart from the gain chip and together form a first external optical resonant cavity; the second light-transmitting reflector is spaced apart from the first light-transmitting reflector and together with the gain chip form a second external optical resonant cavity. The first and second external optical resonant cavities of the external cavity narrow linewidth laser assembly of the present application significantly increase the resonant cavity length within the limited tube shell space. The longer the resonant cavity length, the longer the coherent light length, and thus the narrower the linewidth, achieving higher performance while maintaining a low cost.

The invention discloses a multi-wavelength laser based on a vertical gain cavity, and belongs to the field of semiconductor lasers. Comprising a vertical emission array chip and a silicon-based external cavity chip, the vertical emission array chip is mainly characterized in that light is vertical to the surface of the chip and emits light, the vertical emission array chip comprises at least two vertical emission devices serving as an optical vertical gain area, and the silicon-based external cavity chip comprises a coupler, a phase modulation area, a light reflector, a wavelength division multiplexer and an output area. Mode selection is carried out through the light reflector, light feedback of different wavelengths is achieved, a laser resonant cavity is formed by the light reflector and the vertical emission array chip, and work of multiple single wavelengths is achieved; and finally, wave combination is carried out through a wavelength division multiplexer to form the multi-wavelength laser. The device is high in integration level, good in stability, simple in process and low in cost, and the technical effects of ultra-multiple channels, ultra-narrow linewidth, large output optical power and large-area integration can be achieved at the same time.

A substrate processing apparatus includes an inner chamber formed by an upper portion and a lower portion, a substrate support to support a substrate within the upper portion of the inner chamber, a plasma system to provide the inner chamber with plasma species from the top side of the inner chamber, and an outer chamber surrounding the upper portion of the inner chamber. The lower portion of the inner chamber extends to the outside of the outer chamber and remains uncovered by the outer chamber.

The invention relates to the technical field of semiconductor lasers, in particular to a laser based on a bimetallic Bragg grating and a top surface HR reflecting film, which comprises a gain chip, a first high-reflection HR film is plated on the left end surface of the gain chip, and a first anti-reflection AR film is plated on the right end surface of the gain chip. A metal Bragg grating waveguide is arranged on the right side of the gain chip, an annular resonance optical waveguide is arranged on the front side of the ridge optical waveguide, the right end face of the gain chip and the left end face of the metal Bragg grating waveguide are aligned and attached to form an outer cavity structure, and the left end face of the metal Bragg grating waveguide is plated with a second anti-reflection AR film. The right end face of the metal Bragg grating waveguide is plated with a third anti-reflection AR film. Performance test is carried out on the laser provided by the invention, and test results show that the line width is 0.6 kHz, the SMSR is 63dB, and the threshold current is 22mA, thereby verifying the effectiveness of the laser provided by the invention.

The invention discloses a light modulation sound absorption superstructure which comprises at least one sound absorption back cavity, the sound absorption back cavity comprises an inner cavity and at least one outer cavity which is arranged on the outer side of the inner cavity and is annularly arranged, a cavity division partition plate is arranged between the inner cavity and the outer cavity, and at least two cavity division doors are arranged in the outer cavity and divide the outer cavity into at least two unequal cavity channels. The cavity division partition plate and the cavity division door each comprise a flexible light response driver and a rigid panel which are fixedly connected, a micro-perforated hole is formed in the area, corresponding to the inner cavity, of the upper cover, and the area, corresponding to the outer cavity, of the upper cover is of a transparent structure. According to the invention, the light-driven flexible light response driver is used as a driver, the inner cavity and the outer cavity are arranged, and the driver controls the conduction or separation of the inner cavity and the outer cavity and controls the opening and closing of the unequally divided outer cavities, so that the sound wave equivalent path can be changed, and the sound absorption frequency band of the sound absorber back cavity can be adjusted; and the large-range non-contact adjustment of the sound absorption performance is realized.

The invention relates to a multi-path high-stability narrow-linewidth external cavity semiconductor laser and application thereof, and belongs to the technical field of lasers. The laser comprises two groups of external cavity light paths, Z-block beam combiners, partial reflectors and isolators, the two groups of external cavity light paths are arranged side by side, and the Z-block beam combiners, the partial reflectors and the isolators are sequentially arranged on the light emitting sides of the two groups of external cavity light paths; the external cavity optical path comprises a gain chip, a collimating lens, a polarization analyzer A, a polarization beam splitter, an F-P etalon and a narrow-band-pass filter which are sequentially arranged along the optical path. The polarization analyzer and the polarization beam splitter are arranged in the external cavity light path, main polarized light is kept to resonate in the external cavity light path, the polarization suppression ratio of the external cavity light path is improved, non-dominant mode noise is suppressed, and the line width is reduced; the mode jump risk is reduced, the device life is prolonged, and the power stability is improved; the beam quality is improved; and the polarization dependent loss in a light path is reduced.

The invention discloses an inner cavity of atomic layer deposition equipment and double-chamber atomic layer deposition equipment, relates to the technical field of semiconductors, and aims to solve the problem that in an inner cavity of existing atomic layer deposition equipment, gas is difficult to fully diffuse, so that the uniformity of thin film deposition is poor. The inner cavity of the atomic layer deposition equipment comprises an inner cavity main body, the inner cavity main body is arranged in the atomic layer deposition equipment, an annular groove is formed in the top surface of the inner cavity main body along the center of the top surface of the inner cavity main body, and a source inlet and an extraction opening which are communicated with an outer cavity are formed in the annular groove; the top of the inner cavity body is divided into a substrate bearing portion and an annular gas distribution portion by the annular groove, the annular gas distribution portion is composed of the annular groove, a source inlet, a gas extraction opening and a gas uniformizing cover plate covering the annular groove, and the gas uniformizing cover plate is provided with a gas uniformizing hole array. And the gas-phase precursor injected from the source inlet in the annular groove is diffused to the substrate bearing part through the gas homogenizing hole array.

The invention discloses an output wavelength closed-loop adjustment method and system based on a negative feedback adjustment device, and relates to the field of external cavity quantum cascade lasers. According to the output wavelength closed-loop adjusting method, during the working period of the external cavity wide-spectrum tuning laser, the real-time light spot position is calculated through a negative feedback adjusting device, the real-time light spot position is matched with the light spot position in a calibration data table to obtain the corresponding laser wavelength, and the output wavelength is adjusted by comparing the laser wavelength with the target laser wavelength. Determining a voltage adjustment value, controlling the current working voltage of the galvanometer driver to be increased or decreased according to the voltage adjustment value, and circulating the process until the laser wavelength output by the resonant cavity is stabilized in the target laser wavelength or an allowable error range thereof; accurate control over the rotating angle of the galvanometer is achieved, and repeatability and accuracy of the output wavelength are improved.

The invention provides a picosecond pulse source based on a harmonic self-mode-locking semiconductor surface emitting laser, which comprises an optical pumping assembly and a V-cavity resonant cavity assembly, and is characterized in that the optical pumping assembly comprises a semiconductor bar laser and a collimating focusing lens optical coupling assembly, and the V-cavity resonant cavity assembly comprises a microcavity gain structure and an outer cavity structure; pump laser emitted by the semiconductor bar laser is focused and coupled through the collimating focusing lens optical coupling assembly, then light spots are output, the light spots are absorbed and gained through the microcavity gain structure, and resonance laser is output through feedback resonance of the outer cavity structure. And when the resonant laser in the external cavity structure is matched with the light spot, the external cavity structure outputs a mode-locked pulse after spatio-temporal dynamics calculation and adjustment. The picosecond pulse source realizes harmonic mode-locked pulse output with hundred picosecond pulse width and hundred MHz repetition frequency.

The invention provides a high-power external cavity tunable quantum cascade laser output module. The high-power external cavity tunable quantum cascade laser output module comprises a first lens, a first half-wave plate and a first mid-infrared grid polaroid which are sequentially arranged along a light path of a first laser; a second lens, a second half-wave plate, a second mid-infrared grid polarizer and a third half-wave plate are sequentially arranged along the light path of the second laser; emergent light of the first mid-infrared grid polaroid and the third half-wave plate is converged on different surfaces of the third mid-infrared grid polaroid, the first blazed grating is arranged on a reflection light path of the first mid-infrared grid polaroid, and the second blazed grating is arranged on a reflection light path of the second mid-infrared grid polaroid. According to the invention, the problems of wavelength locking and low polarization beam combination efficiency caused by insufficient polarization state of the quantum cascade laser can be effectively solved, narrow linewidth output and wavelength tuning of the quantum cascade laser can be realized, and even high-power dual-wavelength tunable output can be realized through polarization beam combination structure expansion.

The invention relates to the technical field of lasers, in particular to a narrow-linewidth frequency conversion laser which comprises a DFB laser, a first end of the DFB laser is used for outputting initial fundamental frequency light; the lithium niobate outer cavity comprises a spot size converter, a transmission waveguide provided with a phase shift part, a first multi-mode interference coupler, upper and lower speech channel micro-rings, a second multi-mode interference coupler and a periodically poled waveguide which are connected in sequence, and the upper and lower speech channel micro-rings and a Bragg grating of the DFB laser form a resonant cavity; the upper and lower speech channel micro-rings reflect a part of the received light back to the DFB laser to realize self-injection locking and output the other part of the received light to the second multimode interference coupler, the fundamental frequency light passes through the periodically polarized waveguide to realize frequency conversion, and the output end of the periodically polarized waveguide outputs frequency-doubled light; the lithium niobate outer cavity further comprises two comb-shaped electrodes which are symmetrically arranged on the two sides of the periodically poled waveguide. The performance of the narrow-linewidth frequency conversion laser can be improved at least.

A lithium niobate (LN) external cavity includes a Vernier mirror structure which includes two or more microresonators where: one or more or all of the Vernier microresonators are tuned by the electro-optic Pockels effect of LN, with tuning electrodes integrated with the resonators, and one of the Vernier microresonators could be tuned by the thermo-optic effect, with a local heater integrated with the resonator. One or more or all of the Vernier microresonators include a section or the whole resonator that is periodically poled to achieve quasi-phase matching for nonlinear frequency conversion directly inside the laser cavity. The lithium niobate (LN) external cavity also includes a phase shifter whose phase is tuned by the electro-optic Pockels effect of LN. A Sagnac loop mirror is placed at the end of the device to function as the output end mirror of the laser cavity.

The invention relates to a double-grating external cavity spectrum beam combining device. The device comprises a semiconductor laser array light source, a fast axis collimating mirror, a slow axis collimating mirror, an optical path compensation device, a diffraction grating pair, a collimating lens and an output coupling mirror which are arranged in sequence. The optical path compensation device comprises a plurality of optical path compensation assemblies, and the optical path compensation assemblies are in one-to-one correspondence with sub light beams in the array light beams. An optical path compensation assembly is installed in an independent optical path transmission path of each sub-beam of the array beam, the outer cavity length and the beam combining efficiency of each sub-beam are changed through the optical path compensation assemblies, and specifically, the optical path of each sub-beam can be increased through the design that a reflection assembly installation platform drives a reflection assembly to move upwards, so that the beam combining efficiency is improved. Therefore, the length of the outer cavity is increased, the beam combining efficiency is improved, and the stability and precision of the system can be improved. And finally, the cylindrical lens can compensate optical errors introduced in a light beam transmission process, so that each sub-light beam is ensured to have good wavefront uniformity and phase consistency.

The invention discloses a novel laser mode hopping compensation method. The method comprises the following steps that S1, a constraint bent groove for limiting a steel ball to move under KHz-level vibration is designed; s2, detecting a mode hopping phenomenon and parameters in laser output; s3, outputting a round-trip optical path adjustment amount and a curved groove Y-axis sinkage amount based on the mode hopping parameters obtained in the S2; s4, the corresponding position of the constraint bent groove designed in the S1 is polished and optimized based on the adjustment amount obtained in the S3; and S5, iteratively executing compensation until the laser output has no mode hopping. The invention is characterized by providing a novel mode-hopping compensation external cavity semiconductor laser system and a compensation method which are especially suitable for a TDLAS-WMS technology and can accurately sense the type and concentration of gas to be detected.

The invention relates to the technical field of laser marking, in particular to a laser engraving cutting machine host which comprises a base, a back plate, a back cover, a cover body and a laser module, the back plate is fixed to the base, two sets of protruding plates are formed on the back face of the back plate, middle plates are formed in the middles of the opposite sides of the two sets of protruding plates, and partition plates are fixed between the middle plates and the back plate; a hook plate is fixed on the partition plate and located in the inner cavity, a lifting block connected with the cover body slides in the outer cavity, a guide wheel is arranged on the top of the back plate, and the lifting block is connected with an extension spring. By means of the linkage design of the lifting block and the extension spring, the extension spring bypasses the guide wheel and is fixed to the hook plate, stable tension is formed, it is guaranteed that the cover body cannot rapidly fall off due to gravity in the lifting process, operation safety is improved, working efficiency is improved, an elastic clamping mechanism of the convex block, the reed and the concave block is automatically locked when the cover body is closed, and the cover body is not prone to falling off. And the stability and the safety of the equipment are further enhanced.

A sound instrument (1) with a housing (2) at the opposite longitudinal ends of which support surfaces (4) are formed for resting on a base (5), characterized in that the interior of the housing (2) is divided into three chambers, wherein two outer chambers (7) are provided, between which an inner chamber (8) is provided, that free-flowing filling material consisting of particles (10) can be stored in each outer chamber (7) and in which pressure equalization means are provided, that a partition (6) with a passage opening (9) is provided between each outer chamber (7) and the inner chamber (8), wherein the diameter of the passage opening (9) is adapted to the outer diameters of the particles (10), that prefabricated comb structures (12) forming modules are fixed to the inner sides of side walls of the housing (2), which are oriented transversely to the longitudinal direction of the housing (2).and that, with the housing (2) standing on a base (5) with one of the support surfaces (4), filling material from the upper outer chamber (7) trickles through the passage opening (9) and over the comb structures (12) towards the lower outer chamber (7).

The invention provides a broadband linear frequency modulation microwave source based on ultra-short external cavity modulation light feedback, and relates to the field of microwave photonics. Continuous light generated by the main semiconductor laser is injected into the slave laser after being adjusted, so that the slave laser works in a periodic oscillation state; the slave laser, the electro-absorption modulator and the reflector are integrated to form an ultra-short outer cavity, and the intensity of feedback light is regulated and controlled by an external signal source so as to realize linear scanning of cavity mode frequency. After beam splitting of light output from the laser, one path forms a long external cavity feedback stable signal through the adjustable optical fiber delay line, and the other path outputs a target signal after beat frequency of the photoelectric detector and filtering of the band-pass filter. A high-speed modulator and a high-frequency microwave source are not needed, the broadband advantage of a photonics scheme is reserved, the frequency sweeping bandwidth is further improved to 60 GHz or above, the center frequency and the frequency sweeping range are independently adjustable, the structure is simple, cost is low, integration is easy, and the device is suitable for scenes such as photoelectric radars.