590 results about "Lasing wavelength" patented technology

The invention belongs to the technical field of side slope monitoring, and particularly discloses and provides a side slope deformation three-dimensional monitoring system based on fusion laser ranging, which comprises a deformation rule analysis module, a monitoring switching judgment module, an environment monitoring module, a side slope deformation analysis terminal and a deformation risk processing terminal. According to the invention, by identifying abnormal characteristics such as slope change overlimit, automatically capturing potential high-risk areas such as acceleration abrupt change areas and triggering monitoring setting dynamic updating, the problem of coverage blind areas of fixed monitoring areas is effectively solved, adaptive tracking monitoring of slope high-risk points is realized, and the method is suitable for large-scale popularization and application. Meanwhile, a multi-dimensional slope deformation risk assessment mechanism is constructed by performing fusion processing on a past environment tracking log and a three-dimensional coordinate sequence and setting a deformation risk compensation weight, the limitation of traditional single-point monitoring is broken through, and the slope deformation risk assessment mechanism is established by collecting the humidity of a slope area in real time and selecting laser wavelength. And the interference of environmental noise on three-dimensional coordinate data acquisition is reduced.

The invention relates to a method and a system for detecting the concentration of trace methane by locking the position of an absorption peak, and belongs to the technical field of laser gas detection. Modulated laser output by a laser is divided into two paths, one path enters a reference light path, the other path firstly passes through a gas absorption cell and then enters an actual detection light path, and methane gas with known concentration is sealed in the reference light path; demodulating a modulation signal output by the actual detection light path, and calculating to obtain a trace methane gas concentration value; and demodulating the modulation signal output by the reference light path to obtain a second harmonic signal, comparing the amplitude of the second harmonic signal with the amplitude of a harmonic signal corresponding to a preset methane absorption peak to generate a wavelength shift error signal, and adjusting the driving parameter of the laser through a feedback mechanism to generate a wavelength shift error signal. The output power and wavelength drift of the laser are monitored in real time, and it is ensured that the laser wavelength is always locked within the methane absorption peak range. According to the invention, high-precision and high-stability trace methane concentration detection can be realized.

The invention discloses a method and a device for inhibiting laser wavelength temperature drift, relates to laser wavelength measurement and laser frequency stabilization, and belongs to the field of atomic physics and quantum optics. The device comprises a laser output light unit, a high-precision wavemeter monitoring unit and a temperature drift feedback control unit. And measuring a wavelength drift coefficient a of environment temperature T environment-laser wavelength lambda. Measuring a set temperature Tset-laser wavelength lambda and a wavelength control coefficient b; and according to the measured coefficients a and b, calculating to obtain a temperature gradient compensation coefficient c (c = a / b). When the laser works normally, the T environment is collected in real time, and the set temperature Tset of the laser is changed according to the temperature gradient compensation coefficient c and the T environment, so that the laser wavelength temperature drift is inhibited. According to the invention, active suppression of laser wavelength temperature drift is realized by regulating and controlling a temperature gradient compensation coefficient. The device has the advantages of being simple in structure, high in wavelength drift suppression capability, low in energy loss and the like.

The invention provides a tunable micro-nano laser based on a perovskite phase change material and a preparation method thereof, and belongs to the technical field of micro-nano photoelectron, the tunable micro-nano laser comprises a substrate, and a distributed Bragg reflector, a gain dielectric layer and a reflector which are sequentially arranged on the substrate from bottom to top; wherein the gain medium is a perovskite material with a crystal phase transition characteristic. The substrate is made of a material which is transparent or low in loss to pump light and emitted light; the distributed Bragg reflector is formed by alternately arranging high-refractive-index layers and low-refractive-index layers; the gain dielectric layer is a perovskite thin film layer with a crystal phase transition characteristic, and a perovskite material has a spectrum tuning function in the laser resonant cavity; the reflecting mirror is composed of a metal film. According to the invention, the perovskite material is used as a gain medium and a phase change material at the same time, the wide-range tuning of laser wavelength is realized, and the tuning range can reach several nanometers or even wider; the energy utilization efficiency can be improved, the stability is high, and the method is suitable for various types of tunable micro-nano laser applications.

The invention discloses a high-sensitivity miniaturized HOx free radical accurate measurement device and method, and relates to the technical field of atmospheric environment detection and automatic control, and the device is composed of a free radical generation and removal device, a light source module, longitudinal HOx double cavities, a gas distribution module and a collection and control system. The free radical generation and removal device can generate HOx free radicals or remove OH free radicals; the light source module can emit laser which enables OH free radicals to generate fluorescence and transmit the laser into the longitudinal HOx double-cavity; the longitudinal HOx double cavities are used for exciting OH free radicals to generate a large amount of fluorescence and collecting and converting the fluorescence into electric signals; the gas distribution module is used for injecting gas in the device and maintaining the flowing state of gas flow; and the control and acquisition system is used for controlling automatic operation and data acquisition and processing of the device. The device has the advantages of being high in detection sensitivity, small in size and capable of rapidly obtaining and removing OH free radical measurement interference, rapid calibration of similar concentration can be conducted on the actual HOx concentration in the actual measurement environment, accurate spectrum determination can be conducted on the laser wavelength, and therefore high-sensitivity accurate measurement of HOx free radicals is achieved.

The invention discloses an electronic device parasitic parameter network analysis method based on point cloud deep learning and a related device, and the method comprises the steps: obtaining physical characteristic data in a laser-induced quartz material process, and the physical characteristic data comprises laser wavelength, pulse width, photon energy and material characteristics; and inputting the physical characteristic data into the trained neural network model, and predicting the damage threshold of the laser-induced quartz material. According to the machine learning method fusing physical information, unification of data efficiency and physical consistency is achieved, prediction precision and model expandability are remarkably improved, and the method is used for accurately predicting the damage threshold value of the quartz material under the specific laser condition, so that the laser processing technology is optimized, and the processing precision and efficiency of the quartz material are improved.

The invention discloses a 2 [mu] m nanosecond pulse fiber laser and a time domain waveform adjustment method thereof. The laser comprises a seed source module and an amplification module connected with the seed source module. The seed source module comprises a first high-reflectivity fiber bragg grating, an acoustic optical modulator, a first beam combiner, a first thulium-doped fiber, a 2 * 2 coupler and a second high-reflectivity fiber bragg grating which are connected in sequence, as well as a driving source connected with the acoustic optical modulator and a first pumping source connected with the first beam combiner; the amplification module comprises an online isolator, a second beam combiner, a second thulium-doped optical fiber and an output jumper which are connected in sequence, and a second pumping source connected with the second beam combiner; the rising edge time and the starting time of the acousto-optic modulator are subjected to parameter setting through a human-computer interface of the driving source; the wavelengths of lasers output by the first pumping source and the second pumping source are both 793 nanometers. According to the invention, the multi-peak phenomenon of the Q-switched pulse laser of the 2um waveband can be conveniently and effectively eliminated, the performance of the laser is improved, and the application requirements of low cost and mass production are met.

The invention provides a monitoring device for simultaneously monitoring multiple pollutants in a water environment based on an echo wall mode liquid crystal microcavity and a control method thereof, and belongs to the technical field of optical microsensing. Cholesteric liquid crystal solution doped with fluorescent dye DCM is injected into liquid to be detected through a conical capillary microtube to form a plurality of liquid microsphere cavities; the fluorescent dye DCM in the liquid crystal microspheres emits fluorescence under the excitation of 532 nm laser pulse, high-quality echo wall mode laser emission is generated under the limiting action of the microcavity, and a spectrograph is used for recording a laser spectrum; when the concentration of pollutants in a water environment slightly changes, the change of the refractive index of the liquid crystal causes the change of the wavelength of the laser, so that the spectrum drifts, and high-sensitivity sensing is realized; the invention designs a real-time, quantitative and visual water environment pollutant detection sensor which has a wide application prospect in the field of water environment protection.

The invention discloses an ultrahigh resolution interferometer measurement method and system based on a phase shift gauge block, and the method comprises the steps: placing an ultrahigh resolution interferometer and a preset phase gauge block in a heat preservation box, and introducing two kinds of frequency stabilization laser into the heat preservation box through a single-mode optical fiber; obtaining interference fringe data by adopting a five-step phase shift method, and adjusting the interference fringe data according to the laser wavelength to obtain adjusted data; acquiring environmental data containing the preset phasor block in the heat preservation box, and correcting the adjustment data by eliminating change influence based on the environmental data to obtain corrected data; determining the length of the preset phasor block according to the decimal number of the interference fringes and the integer series of the interference fringes under different wavelengths through a multi-wavelength decimal superposition method, obtaining the measurement data of the Korotkoff interferometer, carrying out the adaptive compensation of the phase shifter, correcting the length according to the uncertainty of the measurement data, and obtaining the phase of the Korotkoff interferometer. The output is a measurement result.

The invention discloses a method for inverting marine primary productivity based on airborne dual-wavelength laser radar remote sensing data, and the method comprises the steps: building a dual-wavelength high-precision water optical characteristic inversion model based on the airborne dual-wavelength laser radar remote sensing data, and obtaining a high-precision marine phytoplankton absorption coefficient vertical section; and inverting the marine primary productivity vertical section distribution coupled with the high-precision phytoplankton absorption coefficient. According to the invention, one laser wavelength is suitable for detecting an offshore sea area, the other laser wavelength is suitable for detecting an open sea area, and the dual-wavelength ocean laser radar improves the maximum detection depth of near and open seas and the inversion precision of the primary productivity vertical section distribution of a typical sea area. And the ocean carbon cycle space-time evolution precision and the observation capability in the aspect of ocean upper-layer energy conversion are further improved.

The invention discloses a nanometer length metering system and method based on chromium atom transition frequency, and belongs to the field of nanometer length metering, the nanometer length metering system comprises a physical wavelength reference and a working standard substance, the physical wavelength reference is a 425.55 nm laser wavelength locked to a chromium atom (7S3-> 7P4) transition spectral line, and the working standard substance is a laser wavelength locked to a chromium atom (7S3-> 7P4) transition spectral line. The working standard substance is chromium self-tracing series gratings prepared by using an atomic photoetching method, grating periods are traced to a physical wavelength reference, and the chromium self-tracing series gratings comprise a one-dimensional chromium self-tracing grating and a two-dimensional chromium self-tracing grating. According to the nanometer length metering system based on the chromium atom transition frequency, the chromium atom transition frequency, which is a natural constant, is materialized to the chromium self-traceability grating in a laser convergence atom deposition manner, so that the grating has independent traceability and ultrahigh accuracy and consistency at the same time.

The invention relates to the technical field of optical instruments, and discloses a visible-ultraviolet dual-wavelength microscope objective and an optical system.The visible-ultraviolet dual-wavelength microscope objective comprises a first lens set with positive focal power and a second lens set with negative focal power which are sequentially arranged from the object plane to the image plane of the microscope objective in the optical axis direction of the microscope objective; the second lens group comprises a front group with negative focal power, a middle group with positive focal power and a rear group with positive focal power; the microscope objective also comprises an aperture diaphragm; the aperture diaphragm is positioned between the two adjacent lenses in the middle group; according to the microscope objective, through reasonable matching of the positive focal power and the negative focal power, the influence of chromatic aberration under a wide-spectrum light source is effectively reduced, the high numerical aperture and the large view field characteristic are kept, and the microscope objective can adapt to the wide-spectrum ultraviolet laser wavelength.

The present invention belongs to the technical field of graphite oxide reduction, and discloses a graphene reduced by graphene oxide, a graphene film and a preparation method thereof. The method comprises the following steps: dispersing graphene oxide in a mixed solution of triethylene glycol to form a graphene oxide dispersion, irradiating with a laser wavelength of 1000 to 1100 nm, washing and drying after the irradiation to obtain graphene. The present invention combines a laser with a wavelength of 1064 nm with a dispersion based on triethylene glycol, which can provide extremely high transient energy for reactants, thereby promoting a deprotonation process and a reduction process, and the prepared graphene is completely reduced, has a large size and few defects.

A photonic assembly, a laser setup having the photonic assembly and a method for performing frequency-modulated continuous-wave light detection and ranging using the laser setup are disclosed. The photonic assembly has an active photonic chip, a photonic modulator chip, and a tuning arrangement having a modulation element having a thickness of 10 micrometers or less. The active photonic chip and the photonic modulator chip are optically coupled such, that injection radiation at an optical feedback wavelength is generated, which defines at least one optical lasing wavelength at which the optical radiation is emitted by the active photonic chip. The modulation element is arranged such, that an actuation of the modulation element tunes the optical feedback wavelength via the Pockels effect, such, that a tuning of the optical feedback wavelength entails a tuning of the optical lasing wavelength.

The invention provides a laser de-bonding method and device, electronic equipment and a storage medium. The method comprises the following steps: determining a de-bonding area on a semiconductor substrate to be de-bonded; wherein the de-bonding area is made of an inorganic material; selecting laser parameters of a pulse laser; wherein the pulse laser comprises any one of a nanosecond laser, a picosecond laser and a femtosecond laser, and the laser parameters comprise laser wavelength and laser pulse width and frequency; and controlling the pulse laser to irradiate the de-bonding area according to the laser parameters. According to the laser de-bonding method, a nanosecond laser, a picosecond laser or a femtosecond laser is adopted to irradiate a de-bonding area on a to-be-de-bonded device, so that de-bonding treatment is carried out on the de-bonding area, and the de-bonding efficiency of taking an inorganic material as a to-be-de-bonded material is improved.

The invention discloses a calibration-free measurement device and method based on wavelength locked cavity ring-down spectroscopy, and the method comprises the steps: S1, carrying out the frequency modulation of laser wavelengths through an electro-optical modulator driven by a radio frequency signal, and obtaining laser of three wavelengths; s2, when the lasers with the three wavelengths enter the optical resonant cavity, turn-off control is carried out on the lasers with the three wavelengths, and a ring-down curve of e index attenuation is obtained; s3, carrying out ring-down signal fitting processing on the ring-down curves of the three wavelengths to obtain ring-down time data at the three wavelengths; and S4, converting the ring-down time data at the three wavelengths into absorption coefficient data at the three wavelengths, and comparing the absorption coefficient data with spectral parameters of absorption lines in a database to obtain the concentration of the gas to be measured so as to realize calibration-free gas measurement. According to the invention, the gas measurement rate is greatly improved, and the complexity and measurement cost of the system are reduced.

The invention relates to the technical field of ultrasonic sensors, and discloses an optical fiber end face integrated micro-cavity sonic sensor which comprises a seven-core optical fiber, two light propagation waveguides, a coupling waveguide, a supporting assembly, a micro disc, a light emitter and a photoelectric detector, the two light propagation waveguides are arranged on the end face of the seven-core optical fiber, the coupling waveguide is arranged between the two light propagation waveguides, and the supporting assembly is arranged on the end face of the seven-core optical fiber. A supporting assembly is arranged on the end face of the seven-core optical fiber, a micro disc is arranged on the top of the supporting assembly, and the first fiber core and the second fiber core are connected with an external light emitter and an external photoelectric detector respectively. The wavelength of the laser output by the light emitter is locked at the linear slope of the micro-disk harmonic peak, the radius and the effective refractive index of the micro-disk are changed through the action of ultrasonic waves on the micro-disk and vibration, the harmonic peak drifts and the intensity of the output laser is changed, and then the ultrasonic waves are detected; compared with the prior art, ultrasonic waves are detected through a micro-disk resonance and laser sideband locking method, and the problem of electromagnetic interference can be effectively avoided by utilizing the optical principle.

The invention relates to the technical field of lasers, in particular to a multi-wavelength laser structure which comprises a heat sink capable of rotating along a rotating shaft, and the rotating shaft is perpendicular to the top face of the heat sink. The wavelengths corresponding to the gain chips in the plurality of gain chips are different, and the plurality of gain chips are annularly arranged on the top surface of the heat sink around the rotating shaft; the output coupling mirror is positioned on one side, far away from the heat sink, of the plurality of gain chips, and the output coupling mirror is matched with the gain chip opposite to the output coupling mirror to form a laser resonant cavity so as to realize laser output; wherein the heat sink rotates along the rotating shaft to switch the gain chips right opposite to the output coupling mirror, when different gain chips are matched with the output coupling mirror, the wavelengths of the lasers output by the multi-wavelength laser structure are different, and the multi-wavelength laser structure at least facilitates the switching of the wavelengths of the output lasers and the simultaneous output of the lasers of multiple wavelengths by adopting a single laser.

The invention discloses a photoacoustic spectrum identification method based on a gas photoacoustic effect. The method comprises the following steps: S1, introducing a multi-component gas mixture into a closed photoacoustic cell; s2, based on the absorption characteristics of different gases, selecting corresponding laser wavelengths to irradiate the gas mixture in the photoacoustic cell; s3, collecting and recording a photoacoustic signal generated by the gas mixture through a high-sensitivity photoacoustic detector; s4, processing and separating the collected photoacoustic signals by using a multivariate analysis algorithm; s5, based on a separation result, identifying and quantifying the concentration of each component gas; according to the photoacoustic spectrum identification method based on the gas photoacoustic effect, separation and identification of signals are achieved, the problem that the equipment cost is greatly increased due to complexity of a light source is avoided, the application field of the photoacoustic spectrum technology is widened, and the method is suitable for popularization and application. The problem that separation is difficult due to overlapping of photoacoustic signals of different gases in multi-component gas mixture detection in the prior art is solved.

The embodiment of the invention relates to the field of antenna calibration, in particular to an antenna gain calibration system and method based on Rydberg atoms, and the system comprises a frequency stabilization module of a detection light source, a light path module, a microwave module, a signal detection module and a darkroom. A frequency stabilization module of the detection light source is used for stabilizing the laser wavelength of a semiconductor laser in a light path module, so that the laser wavelength is suitable for detection light of a Rydberg electromagnetically induced transparency (EIT) system; the light path module is used for generating coupling light and detection light; the coupling light and the detection light are oppositely emitted in an alkali metal atom gas chamber in the darkroom, alkali metal atoms in the alkali metal atom gas chamber are excited to be in a Rydberg state through two-stage excitation, and an EIT signal window needed by an experiment is obtained; the microwave module is used for generating and transmitting a microwave signal to control a microwave electric field in an experiment, and the microwave electric field influences an EIT signal; the signal detection module is used for converting the detection light into an electric signal, and the electric signal is collected through an oscilloscope in the signal detection module so as to be analyzed.

The invention discloses an automobile part location degree measuring method and device, a product and a storage medium, and relates to the field of electrical digital data processing.The method comprises the steps that three-dimensional contour coordinates of a plastic surface layer are determined based on surface reflected light intensity data, and the optical path difference of laser from the plastic surface to a metal insert is calculated according to internal refracted light intensity data; calculating the depth position of the metal insert according to the optical path difference and the refractive index of the plastic material; determining the spatial position relation of the metal insert structure relative to the plastic surface layer by combining the three-dimensional contour coordinate and the depth position; calculating an actual assembly deviation value between the spatial position relation and the standard assembly position; when the actual assembly deviation value is greater than a preset first threshold value, selecting a preset laser wavelength combination according to the actual assembly deviation value; and scanning the automobile part according to the preset laser wavelength combination to obtain a location degree measurement result. By implementing the method, the measurement precision of the metal insert in the automobile part can be improved.

The invention discloses an intelligent visual detection system for a high-precision printed circuit board, and relates to the technical field of precision optical detection.The intelligent visual detection system comprises the steps that based on a printed circuit board substrate with a quantum dot mark layer attached to the surface, confocal scanning is conducted through laser wavelength, and an original image data set is generated; performing multispectral feature analysis on the original image data set, capturing focus offset rules of light rays with different wavelengths, and generating a wavelength-focus mapping relation compensation instruction set; according to the compensation instruction set of the wavelength-focus mapping relation, an imaging light path is adjusted in real time, and a high-fidelity fusion image is generated; and analyzing optical signal feature changes in the high-fidelity fusion image, identifying an abnormal region, extracting microdefect features, and generating a detection report containing the defect features. According to the invention, through uniform dispersion of the quantum dot modified ink in the inert atmosphere and a plasma substrate activation process, molecular-level combination of the solder mask layer and the fluorescent marking material is realized.

The invention belongs to the technical field of optical beauty, and discloses a medical beauty device with an LED light source and a body beauty system based on phototherapy, and the method comprises the steps: collecting multi-source data for fusion, and generating a skin health map through an ICP registration algorithm; based on the skin health map, segmenting a high-tolerance area and a blood vessel dense area; distributing laser wavelength, energy density and cooling parameters for each area; the dynamic thresholds are adjusted in real time in a self-adaptive mode through the dynamic thresholds; determining and dividing risk grades through multi-parameter fusion, triggering a grading response mechanism, and generating dynamic energy configuration parameters and a safety control strategy; based on the three-dimensional point cloud coordinates and spatial constraint conditions, dynamically adjusting laser path planning through a path re-planning algorithm, and generating a phototherapy execution log; generating a curative effect evaluation report based on the phototherapy execution log, and constructing a photoaging risk map; and updating the energy rule base through a reinforcement learning algorithm, and determining parameters of a threshold value and a weight coefficient of a registration algorithm to form closed-loop optimization.

The invention relates to an energy-level-controllable small laser irradiation grafting and crosslinking system and an application method thereof, and belongs to the technical field of material processing and modification. The system is composed of an adjustable laser source, a focusing optical system, a laser energy regulation and control module, a machining platform, a chemical reaction auxiliary module, a real-time monitoring and feedback system and an intelligent control system, laser wavelength, power and pulse width can be accurately controlled, and micron-level machining precision is achieved. Compared with a traditional chemical grafting method, a thermal induction crosslinking method and a plasma treatment method, the method has the remarkable advantages of non-contact processing, low energy consumption, high precision, environmental friendliness and the like. The system supports efficient grafting and crosslinking of various materials (such as polymers, metals and ceramics), the processing efficiency and the material performance are remarkably improved, and an innovative solution is provided for material functionalization and green manufacturing.

The grating layer of a surface emitting laser is divided into a first grating region and a second grating region along a horizontal direction. The second grating region is located at a middle area of the grating layer, while the first grating region is located in an outer peripheral area of the grating layer. Each of the first and second grating regions comprises a plurality of micro-grating structures. The grating period of the micro-grating structures in the first grating region is in accordance with the following mathematical formula:⋀=m⁢λ2*neff;in addition, the grating period of the micro-grating structures in the second grating region is in accordance with the following mathematical formula:⋀=o⁢λ2*neff.Wherein, ∧ is the length of grating period, λ is the wavelength of the laser light, neff is the equivalent refractive index of semiconductor waveguide, m=1, and o=2. The first grating region is a first-order grating region, and the second grating region is a second-order grating region, so as to form a hybrid grating structure in the grating layer. The surface emitting laser emits laser light perpendicularly from a light-emitting surface defined by the second grating region.

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 utility model discloses an optical feedback type formaldehyde detection device which comprises a semiconductor laser, an absorption cell is mounted at the output end of the semiconductor laser, and a piezoelectric ceramic crystal is mounted on one side of the absorption cell; a photodiode and a laser diode are arranged in the semiconductor laser, and the output end of the laser diode is connected to the input end of the photodiode through an optical signal; the output end of the photodiode is provided with a Fourier transform module; the input end of the laser diode is provided with a driving module; a formaldehyde sampling pump is arranged at the input end of the absorption tank; the input end of the piezoelectric ceramic crystal is provided with a control module. The device adopts the length change of piezoelectric ceramics to modulate the light wave phase, forms carrier waves absorbed by formaldehyde gas, and has the advantage of reducing the detection difficulty; the laser device adopted by the device is a single longitudinal mode semiconductor laser device, laser wavelength can be finely adjusted according to a formaldehyde gas absorption wave band, and the device has the advantage of high sensitivity.

An optical source is described. This optical source may include a semiconductor laser chip and a silicon-photonics chip that provide an optical cavity. The semiconductor laser chip may provide gain at multiple lasing wavelengths in a band of wavelengths. Moreover, the silicon-photonics chip may adjust a size of an optical signal proximate to an interface between the semiconductor laser chip and the silicon-photonics chip. Furthermore, by adjusting a phase of a phase shifter and resonance frequencies of a micro-ring resonator in the silicon-photonics chip, a center frequency of a passband of the micro-ring resonator may be matched to a non-zero integer multiple of a cavity-mode spacing. This may allow the optical source to mode-lock the lasing wavelengths of the optical source by suppressing unwanted lasing wavelengths and re-enforcing the lasing wavelengths. In some embodiments, a free-spectral range of the optical source may be between 100 GHz and 800 GHz.

According to the laser chip capable of inhibiting in-plane amplified spontaneous emission, the first inclined edge and the second inclined edge are designed, opposite edges parallel to the first cleavage edge and the second cleavage edge respectively are damaged, a first parasitic cavity and a second parasitic cavity existing in a natural cleavage laser chip are eliminated, and the laser chip can inhibit in-plane amplified spontaneous emission. Therefore, the formation of in-plane amplified spontaneous emission of the laser chip is remarkably inhibited, meaningless consumption of carriers in a laser emission layer in the laser chip is prevented, the luminous efficiency of the laser chip on laser wavelength can be improved, the light-light conversion efficiency of the laser from pump light to emission laser is improved, and the output power of the laser is finally improved. And secondly, due to the suppression of amplified spontaneous radiation in a laser chip plane and the improvement of the light-light conversion efficiency of the laser, the power consumption of the laser can be obviously reduced under the condition of certain output power, the operation cost of the laser is reduced to a certain extent, and the cost performance of the laser is improved.