102 results about "Longitudinal mode" patented technology

The invention provides a quasi-continuous thulium-doped fiber laser capable of synchronously suppressing relaxation oscillation and self-pulse, relates to the technical field of fiber laser, and is used for simultaneously realizing suppression of a self-pulse effect and a relaxation oscillation peak. Comprising a continuous driving module, a pulse driving module, a semiconductor laser pumping source, a high-reflectivity fiber bragg grating, a low-reflectivity fiber bragg grating, a beam combiner, a thulium-doped gain fiber, a passive fiber, a cladding pumping stripper and a laser output port, the continuous pump light and the pulse pump light are respectively driven by the continuous driving module and the pulse driving module to output continuous pump light and pulse pump light; the high-reflectivity fiber bragg grating and the low-reflectivity fiber bragg grating form a resonant cavity structure, the thulium-doped gain fiber serves as a gain medium of the thulium-doped fiber laser and absorbs pump light to generate population inversion, laser oscillation is formed by combining the resonant cavity of the laser, relaxation oscillation suppression is achieved, and meanwhile longitudinal mode distribution of the laser is effectively disrupted.

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 semiconductor lasers, in particular to a multi-wavelength semiconductor laser. Comprising a semiconductor PN junction, and an inclined array waveguide region, a beam splitting MMI structure, a gain array waveguide, a beam combining MMI structure and a super-symmetric waveguide array which are sequentially arranged on the surface of the semiconductor PN junction in the longitudinal mode light beam transmission direction; the inclined array waveguide region comprises Bragg reflection gratings and inclined array waveguides, the Bragg reflection gratings are arranged on ridge surfaces of inlet ends of the inclined array waveguides, cavity lengths of waveguides in the inclined array waveguides are different, and the Bragg reflection gratings are parallel; seed sources output by the inclined array waveguide region are injected into the beam splitting MMI structure, and the seed sources are uniformly distributed and coupled into each waveguide of the gain array waveguide; the gain array waveguide is a parallel waveguide; the super-symmetric waveguide array is used for providing further gain to a fundamental mode and loss to a high-order mode. The antenna has the advantages of simple preparation, high gain, high single-mode performance, small size and high integration.

The invention discloses a device for generating Mach-Zehnder interference, a photo-thermal spectrum gas sensing device based on the device and a detection method, and belongs to the technical field of laser spectrum gas sensing. The interference device sequentially comprises an optical frequency comb and a first light beam splitter on a light transmission path; a movable arm reflector group is arranged on the light path of one light beam B in the two light beams split by the first light beam splitter, the path of the light beam B is changed through the movable arm reflector group, the light beam B intersects with the light path of the other light beam C, and a beam combiner is arranged at the intersection; the movable arm reflector group is connected with a driving mechanism, the driving mechanism is used for driving the movable arm reflector group to do linear motion, and the track of the linear motion is parallel to the straight line where the light beam B is located. The interference device does not need to use a local oscillator optical comb and a signal optical comb to carry out multi-heterodyne interference, can directly use the moving speed of a movable arm reflector group in a Mach-Zehnder interference structure to calculate a down-conversion factor, and maps each longitudinal mode of the signal optical comb in an optical frequency to a radio frequency component one by one.

The invention discloses a laser device mode hopping detection method, and relates to the technical field of laser detection. Comprising the following steps: a to-be-tested laser emits an optical signal, and the optical signal of the laser is converted into an electric signal; and analyzing the frequency spectrum of the electric signal, and determining whether the laser generates mode hopping or not by judging whether a cross relaxation signal caused by double longitudinal modes exists in the frequency spectrum or not. The laser mode hopping detection method provided by the invention is simple in structure, can realize mode hopping real-time monitoring only through the photoelectric detector and the spectrum analyzer, and is low in cost and convenient to deploy; an interferometer or a delay fiber is not needed in the detection process, the anti-interference capability is high, and mode hopping is visually judged through frequency spectrum changes.

Provided in the present application is a laser longitudinal mode measurement device, comprising a filtering module (20) for filtering laser, a tuning module (30) for at least adjusting the bandpass position of the filtering module, and a detection module (40) for detecting laser. Laser from a laser device (10) is filtered by the filtering module and then output, and is transmitted to the detection module for measurement. A filtering module is provided, such that single-longitudinal-mode laser can be obtained after laser is filtered by the filtering module; a tuning module adjusts the bandpass position of the filtering module, such that the frequency range of the laser can be sequentially scanned; and by means of a detection module, the number of longitudinal modes can be obtained, thereby filling the gap where the number of longitudinal modes of laser cannot be measured, and thus making accurate measurement of the number of longitudinal modes of the laser possible.

A semiconductor laser element capable of achieving a single or nearly single longitudinal mode of an oscillation wavelength is provided. A semiconductor laser element includes a nitride semiconductor laminate including a first end surface, a second end surface, and an optical waveguide. The nitride semiconductor laminate includes a first n-side nitride semiconductor layer, a second n-side nitride semiconductor layer, an active layer, and a p-side nitride semiconductor layer. The first n-side nitride semiconductor layer includes a diffraction grating region provided with a periodic structure in which a refractive index changes periodically along a resonance direction of the optical waveguide, and a non-diffraction grating region located between the diffraction grating region and the first end surface and not provided with the periodic structure.wherein the active layer includes an n-side well layer and an n-side barrier layer, wherein the second n-side nitride semiconductor layer is a nitride semiconductor layer containing In and Ga, and wherein a thickness of the second n-side nitride semiconductor layer is greater than a thickness of the n-side barrier layer.,

The invention discloses a laser acceleration tabulation method, which belongs to the technical field of optical fiber sensing and signal processing, is used for constructing a laser wavelength current lookup table, and comprises the following steps of: initializing a laser, configuring five paths of current to carry out two-dimensional nested cyclic scanning, and measuring the central wavelength and side mode rejection ratio of an optical signal. Constructing a central wavelength sequence and dividing a continuous longitudinal mode region; constructing a theoretical sampling grid and a theoretical sampling point set, calculating the number of actual sampling points by using a Gaussian distribution rule, and constructing a sparse measurement training data set; and constructing and training a K singular value decomposition model, and inputting the to-be-detected target wavelength list into the trained K singular value decomposition model to obtain a wavelength current lookup table. According to the method, the K singular value decomposition algorithm is fused into the laser wavelength current lookup table construction process, so that the time cost is reduced, the measurement load is reduced, the deployment flexibility is enhanced, and the construction efficiency of the laser wavelength current lookup table is greatly improved.

The invention relates to the technical field of solid lasers, and particularly provides a narrow-linewidth tunable dual-wavelength laser output system based on data driving, which comprises a pumping source, a resonant cavity, a data acquisition unit and a data receiving and driving device, a single gain medium, two F-P etalon and an F-P angle regulator are arranged in the resonant cavity, the inclination angles of the two F-P etalon are adjusted through an F-P angle adjuster so as to perform longitudinal mode selection and wavelength tuning on the output laser of the resonant cavity; a neural network screening model is arranged in the data receiving and driving device, the neural network screening model is used for learning the mapping relation between intracavity parameters and output laser optical parameters, and dual-wavelength simultaneous locking and line width prediction are achieved through dual-etalon collaborative mode selection and data driving of the neural network screening model. According to the invention, the complexity of the system is greatly simplified, and dual-wavelength, narrow-linewidth, high-stability, repeatable and automatic laser output regulation and control which cannot be achieved by a traditional architecture are realized functionally.

The invention provides a pipeline long-distance guided wave detection system and a detection method thereof, and relates to the technical field of guided wave detection. Torsional mode signals and longitudinal mode signals reflected by guided waves in a target pipeline are collected; the frequency dispersion characteristic of the torsional mode signal is corrected, and the echo characteristic of the torsional mode is determined through the amplitude difference and the phase offset of the corrected torsional mode signal in the circumferential sensor array; compensating the axial symmetry vibration amplitude in the longitudinal modal signal through the attenuation coefficient of the axial propagation of the guided wave in the pipeline structure body and the correlation constraint of the intensity of the guided wave between the axially adjacent sensors, and extracting the echo characteristics of the longitudinal modal; multi-mode guided wave cooperative detection is conducted on the target pipeline according to the echo features of the torsional mode and the longitudinal mode, the defect echo features of the target pipeline are obtained, the defect position of the inner wall of the target pipeline is positioned based on the defect echo features, multi-mode guided wave cooperative detection can be achieved, and therefore the pipeline defect detection precision is improved.

The invention provides a control method and system of a reconfigurable optical phased array device. The control system comprises an MEMS micromirror array, a silicon-based waveguide array, a mode switching device and a controller, and the controller is configured to configure laser output parameters including a central wavelength, a tuning range and single longitudinal mode output control information, initialize the phase shifter position of each array element of the optical phased array, and control the phase shifter position of each array element of the optical phased array. Setting an initial deflection angle of the MEMS micromirror array and initializing a working state of the mode switching device; and receiving target scene information and judging whether the target scene information is changed or not, if so, generating a control instruction according to the target scene information, and controlling the optical phased array device according to the control instruction. The high integration of the optical system is realized by utilizing the high integration characteristic of the silicon-based optical chip and combining the design of the MEMS micromirror array and the mode switching device, and the overall performance and efficiency of the system are improved.

The invention provides a tunable external cavity laser chip and a preparation method thereof, and relates to the technical field of lasers, the chip comprises a planar optical waveguide loop and a gain chip; a narrow-band transmission peak of a micro-ring resonator and an interference passband of a multi-channel interference module are preliminarily aligned through a phase shifter array and a first micro-ring phase shifter in a planar optical waveguide loop, and selection of a lasing working point is completed; and the common phase shifter and the second micro-ring phase shifter are used for cooperative driving, laser frequency sweeping is carried out on the basis of preliminary alignment, and accurate alignment of a narrow-band transmission peak and an external cavity longitudinal mode is maintained in the whole frequency sweeping process. Through cooperative driving of the common phase shifter and the micro-ring phase shifter, the sweep frequency bandwidth of the laser is increased, and frequent mode hopping of output laser in the tuning process is avoided; meanwhile, the periodic alignment reflection phenomenon in a reflection spectrum is avoided, the utilization rate of the gain interval of the semiconductor gain chip is greatly improved, and a larger tuning range is obtained under the condition that the quality of light beams is kept unchanged.

The invention discloses a wavelength tunable laser. The wavelength tunable laser comprises a base station; the resonant cavity is arranged on the base station; the gain medium is arranged on the base station and is positioned in the resonant cavity, so that the pump light forms oscillation light propagating in the resonant cavity when entering the gain medium, and the oscillation light forms output light of the tunable laser; the mode selecting part is arranged on the base station, is positioned on a propagation path of the oscillating light and is used for selecting light with corresponding wavelength from the oscillating light to form single longitudinal mode output light; and the first temperature control device is connected with the base station and is used for controlling the temperature of the base station to change the length of the resonant cavity so as to adjust the wavelength of the single longitudinal mode output light. The resonant cavity, the gain medium and the mode selection part are all arranged on the base station, the temperature of the base station is adjusted, the base station deforms due to the thermal expansion and cold contraction property, the length of the resonant cavity is changed, the oscillation light propagation optical path in the resonant cavity is changed, single longitudinal mode wavelength tuning of the wavelength tunable laser can be achieved, the structure is simple, and cost is low. And the tuning operation is relatively simple.

The embodiment of the invention provides a complex special-shaped structure three-dimensional stress inversion method based on ultrasonic characteristic guided waves, and the method comprises the steps: obtaining first ultrasonic characteristic guided waves corresponding to a plurality of characteristic guided wave modes of a detected special-shaped structure in a detection process, the multiple characteristic guided wave modes comprise at least two of a longitudinal mode, a torsional mode and a bending mode; according to the first ultrasonic characteristic guided waves corresponding to the multiple characteristic guided wave modes, first group velocities corresponding to the multiple characteristic guided wave modes of the detected special-shaped structure are calculated, and a first group velocity matrix is obtained; and inputting the first group velocity matrix into a pre-trained physical information neural network model to obtain the current stress information of the detected special-shaped structure, through the scheme of the embodiment of the invention, the stress information of the special-shaped structure can be calculated through the pre-trained physical information neural network model, and the accuracy of the stress information of the detected special-shaped structure is improved. And high-efficiency and high-precision nondestructive stress measurement is achieved.

The utility model discloses a wavelength tunable 2 [mu] m single longitudinal mode all-solid-state pulse laser, which belongs to the technical field of lasers, and comprises a pumping source, the output end of the pumping source is provided with a 1: 2 optical coupling system, the output end of the 1: 2 optical coupling system is provided with an input mirror, the output end of the input mirror is provided with a Tm: YAP crystal, and the Tm: YAP crystal is used for generating 2 [mu] m laser; the output end of the Tm: YAP crystal is provided with an acousto-optic modulator, the output end of the acousto-optic modulator is provided with an etalon, the output end of the etalon is provided with a birefringence filter, and the output end of the birefringence filter is provided with an output mirror. The wavelength tunable 2 [mu] m single longitudinal mode all-solid-state pulse laser is simple in structure, can stably generate 2 [mu] m laser, provides a wider wavelength tuning range and more direct tuning, and realizes narrower spectral width at the same time.

The invention provides a narrow-linewidth high-power output external cavity semiconductor laser, and relates to the technical field of laser. The narrow-linewidth high-power output external cavity semiconductor laser comprises a packaging shell, a gain chip, a collimating lens assembly, an etalon assembly, a volume Bragg grating and a laser output assembly, a cavity is formed in the packaging shell, and the gain chip, the collimating lens assembly, the etalon assembly and the volume Bragg grating are all arranged in the cavity. A volume Bragg grating is adopted as a mode selection feedback element, and a single longitudinal mode can be selected in combination with a gain curve; the etalon assembly is arranged on the laser light path between the collimating lens assembly and the volume Bragg grating, the etalon assembly can improve the Q value of the laser resonant cavity and compress the laser line width, the laser line width can reach the kHz magnitude, the output power can reach tens of mW, and the whole laser has the advantages of being compact in structure, high in stability and high in environmental adaptability.

The application provides a semiconductor structure and a preparation method thereof and a semiconductor laser, and relates to the field of lasers. The semiconductor structure comprises a substrate, a first waveguide layer, a resonant structure and a second waveguide layer; the first waveguide layer is arranged on the surface of the substrate along the thickness direction; the resonant structure comprises an active region, an input layer and an output layer; the active region, the input layer and the output layer are arranged on the side of the first waveguide layer away from the substrate; in a plane parallel to the plane in which the substrate is located, the input layer and the output layer are located on the two sides of the active region, and the output layer is arranged obliquely; in the direction away from the substrate, the output layer is away from the input layer; the second waveguide layer is arranged on the side of the resonant structure away from the surface of the first waveguide layer, and the second waveguide layer is connected with the resonant structure. The application can reduce the possibility of interference effect between reflected light and the light field in the FP cavity, make the longitudinal mode output of the semiconductor structure more stable, and improve the spectral purity of the semiconductor structure.

The invention belongs to the technical field of optics, and particularly relates to a device and method for preparing a preset grafting perfect vector vortex light generator. According to the invention, laser output by a single longitudinal mode laser passes through a beam expanding lens barrel and a polarization beam splitter and then is divided into crop light and reference light; object light passes through a space phase encoding module, a first half-wave plate, a Q-wave plate and a Fourier plane filtering module and then interferes with reference light passing through a reflector, a second half-wave plate and a fan-shaped diaphragm in a photo-induced anisotropic medium, and a spliced hologram is recorded through two times of exposure; and the medium is read by using p polarized light meeting the Bragg condition, so that the grafting perfect vector vortex light of the preset Pancharatnam topological charge and the polarization order can be reconstructed. The system is compact in structure, low in cost and high in integration degree.

The utility model discloses a multi-channel multi-wavelength semiconductor laser light source device for optical I / O. A parallel multi-wavelength semiconductor DFB laser array prepared based on REC technology, a beam splitting / routing device under different material systems and an optical fiber array FA are connected through optical coupling components, and a large number of laser channels are integrated. The parallel multi-wavelength semiconductor DFB laser array prepared on the basis of the REC technology is good in single longitudinal mode stability and accurate in wavelength control, the stability and improvement of the performance of a data transmission system are facilitated, the PWB waveguide coupling mode can be adopted, integration of a large number of laser channels can be achieved more easily, and the integration efficiency is improved. The size of the device is further reduced, and the device has better mechanical reliability.

The invention discloses a metasurface grating waveguide based on a silicon carbide substrate and an enhanced display system, and belongs to the technical field of optoelectronic device manufacturing, and the key points of the technical scheme are that the metasurface grating waveguide comprises a tunable light source, a spatial light modulator, a metasurface grating waveguide, an imaging device and a processing device, modulating the phase distribution of the light to obtain a light beam carrying image information; the processing device is used for adjusting the wavelength of light emitted by the tunable light source and the length of an optical resonant cavity according to the current temperature, and the optical resonant cavity is located in the tunable light source; the metasurface grating waveguide comprises a silicon carbide substrate and is used for conducting a light beam emitted by the focusing lens to the pupil expander so that the pupil expander can output image information to human eyes, the length of the outer cavity is adjusted firstly so that the longitudinal mode frequency can be aligned with the gain peak corresponding to the target wavelength, then the current is adjusted so that the wavelength can reach the target wavelength, and therefore image information can be obtained. The problem of uneven final imaging brightness can be solved while mode hopping is avoided.

The invention discloses a miniaturized adjustment-free ultra-narrow linewidth composite filtering external cavity semiconductor laser, which belongs to the field of semiconductor lasers and is sequentially provided with a gain chip, an aspherical lens, a first FP etalon, a second FP etalon, an interference filter, a partial reflector, an optical isolator and a polarization maintaining optical fiber collimator. Wherein the first FP etalon and the second FP etalon are superposed in a non-coaxial mode to form a free spectral range difference, a longitudinal mode interval difference is generated through a Vernier effect, and a longitudinal mode interval generated by the Vernier effect is controlled by adjusting a dip angle difference between the first FP etalon and the second FP etalon. Through machining precision, optical coupling optimization and an automatic assembly technology, the problems of wide tuning bandwidth, ultra-narrow linewidth, multi-dimensional performance collaboration and environmental adaptability are synchronously solved.

The utility model relates to the technical field of optics, and provides an optical sensor which comprises a laser light source, a filtering device used for filtering laser, a sensing device used for sensing external factors and a measuring device at least used for measuring the number of longitudinal modes of the laser. The measuring device is arranged on an output path of the filtering device; laser of the laser light source is output after being filtered by the filtering device, and is transmitted to the measuring device for measurement; a filtering device, a sensing device and a measuring device are arranged, environmental factors are sensed through the sensing device, the filtering device is influenced, the band-pass position and / or the band-pass width of the filtering device are / is changed, and then the longitudinal mode number and / or the longitudinal mode position of laser output after passing through the filtering device are / is influenced. The measurement module is used for measuring changes of the number and / or the position of longitudinal modes in laser, so that measurement and monitoring of tiny changes of external factors can be achieved, the measurement precision is high, and the application field is wide.

The application is suitable for the technical field of optical coupling, and provides a non-contact displacement control system and a displacement control method. The system comprises a displacement platform, a spectrometer and a control device, and is applied to displacement control of a light source emitting end and a first port of an optical fiber to be optically coupled. The displacement platform is used for fixing the first port of the optical fiber, the spectrometer is used for connecting a second port of the optical fiber, and the control device is connected with the spectrometer and the displacement platform respectively. The light source emitting end and the first port of the optical fiber form an optical cavity. The spectrometer detects and sends a longitudinal mode spacing of the optical cavity to the control device based on a light signal emitted by the light source emitting end. The control device controls the displacement platform to drive the first port of the optical fiber to move based on the longitudinal mode spacing, and adjusts a distance between the first port of the optical fiber and the light source emitting end. The application can accurately control micron-level displacement changes while ensuring that a contact measurement surface is not damaged or contaminated.

The invention provides a control method and device of a pulse laser and the pulse laser, and belongs to the technical field of lasers, and the method comprises the steps: controlling the linear loss in a resonant cavity to be at a first loss level through a linear loss modulator before a pulse is established, maintaining the first loss level for a preset time, and enabling the interior of the resonant cavity to establish preliminary oscillation light; the longitudinal mode selector is used for screening out a target longitudinal mode from the preliminary oscillation light; and utilizing the linear loss modulator to control the linear loss in the resonant cavity to be at a second loss level so as to drive the target longitudinal mode to be quickly amplified in the resonant cavity, thereby forming and outputting pulse laser. According to the invention, the first loss level is forcibly maintained for a period of time before the pulse is generated, and the precise screening of the target longitudinal mode is completed in the initial oscillation light circulation of the long period of time by using the longitudinal mode selector, so that the problem of frequency drift between pulses in the pulse laser is effectively solved.

The application discloses a laser radar, which comprises a narrow-line-width multi-longitudinal-mode pulse laser, a photoelectric detector, a perforated mirror beam receiving system, a high-resolution narrow-line-width light splitting device and a plurality of single-photon detectors. The output beam of the narrow-line-width multi-longitudinal-mode pulse laser is emitted through the perforated mirror, and the photoelectric detector serves as a local signal. The echo signal photons reflected by a target are received through the receiving system, and are subjected to angle selection and spectral matching filtering through the light splitting device, and finally subjected to logical AND gate operation through the plurality of single-photon detectors, so that the final signal is simultaneously input into a time-correlation single-photon counter. The working performance of the photon counting laser radar in a strong noise environment is effectively improved, the false alarm probability of the laser radar is greatly reduced under the condition of ensuring the detection probability, the grating combined with the plurality of detectors can greatly reduce the background noise, the signal-to-noise ratio of the echo signal is greatly improved, and the detection capability of the laser radar is improved.

The application discloses a super surface grating waveguide based on a silicon carbide substrate and an enhanced display system, and belongs to the technical field of optoelectronic device manufacturing, and the technical scheme is characterized by comprising a tunable light source, a spatial light modulator, a super surface grating waveguide, an imaging device and a processing device, the spatial light modulator is used for receiving light emitted by the tunable light source, modulating the phase distribution of the light, and obtaining a light beam carrying image information; the processing device is used for adjusting the wavelength of the light emitted by the tunable light source and the length of an optical resonant cavity according to the current temperature, the optical resonant cavity is located in the tunable light source; the super surface grating waveguide comprises a silicon carbide substrate and is used for conducting the light beam emitted by a focusing lens to a pupil expander, so that the pupil expander outputs image information to a human eye, and the application can avoid mode jumping and solve the problem of uneven final imaging brightness by adjusting the length of an external cavity first, aligning the gain peak corresponding to the target wavelength of the longitudinal mode frequency, and then adjusting the current to make the wavelength reach the target wavelength.

This invention relates to the field of solid-state laser technology, specifically providing a data-driven narrow-linewidth tunable dual-wavelength laser output system. The system includes a pump source, a resonant cavity, a data acquisition unit, and a data receiver and driver. The resonant cavity contains a single gain medium, two F-P etalons, and an F-P angle adjuster. The tilt angle of the two F-P etalons is adjusted by the F-P angle adjuster to perform longitudinal mode selection and wavelength tuning of the output laser. The data receiver and driver incorporate a neural network screening model. This model learns the mapping relationship between intracavity parameters and output laser optical parameters, utilizing the dual etalons for collaborative mode selection. The data-driven approach of the neural network screening model achieves simultaneous dual-wavelength locking and linewidth prediction. This invention significantly simplifies system complexity and functionally achieves dual-wavelength, narrow-linewidth, high-stability, repeatable, and automated laser output control, which is impossible with traditional architectures.

This invention provides a single longitudinal mode fiber laser based on a linear main cavity combined with a traveling wave auxiliary cavity, relating to the technical field of laser equipment. The laser includes: a first reflecting device, a gain medium, a composite sub-cavity, a second reflecting device, and a pump source. The composite sub-cavity includes a first circulator, a second circulator, a first beam splitter, and a second beam splitter. The first circulator and the second circulator are connected to the resonant cavity. The first circulator is connected to both the first beam splitter and the second beam splitter, and the transmission direction of the optical paths connecting the first circulator to both the first and second beam splitters is unidirectional. The second circulator is connected to both the first and second beam splitters, and the transmission direction of the optical paths connecting the second circulator to both the first and second beam splitters is unidirectional. A unidirectional circulating optical path is formed between the first and second beam splitters.

A high-speed directly modulated semiconductor laser device and a preparation method therefor. The semiconductor laser device includes an optical waveguide and an optical grating, which is formed by means of a one-step etching process, wherein the optical grating includes a first optical grating portion and a second optical grating portion, which are arranged side by side. The first optical grating portion and the second optical grating portion can effectively control a lasing wavelength and a photon-photon resonance frequency, and generate a load mismatch resonance effect, such that a relatively high yield can be realized while effectively improving the modulation bandwidth of the directly modulated semiconductor laser device, and an FP cavity is prevented from being formed from the reflection of front and rear end faces of the laser device, and thus multi-longitudinal-mode oscillation generated by the laser device at a high temperature or low temperature is prevented.

An optical cavity array includes a plurality of mirrors that form an optical cavity, a first lens system located within the optical cavity, and a second lens system located within the optical cavity. The first lens system has a first output facing a first mirror of the plurality of mirrors and a second output facing a second mirror of the plurality of mirrors. The second lens system has a second input facing the first input and a second output facing the second mirror. The first and second lens systems are configured such that the optical cavity supports longitudinal modes that are transversely non-degenerate, forming spatially separated waists that lie along a focal plane that is axially located between the first and second inputs. When the longitudinal modes are excited, the waists may be used as an array of optical dipole traps.