90 results about "Laser linewidth" patented technology

The invention discloses an anti-interference target laser ray extraction method. The method comprises the following steps of S1, performing Gaussian filtering processing on an image; s2, determining possible starting and ending position points of the target laser ray: the starting and ending position points of the target laser ray are respectively b and b1, the difference value of two adjacent pixel gray values is diffval, and the determination method of b and b1 is as follows: the determination method of b: b-a < = diffval and c-b > = diffval; the determination method of b1 is as follows: b1-a1 is greater than or equal to-diffval, and b1-c1 is less than or equal to-diffval; wherein a and c are two adjacent points on the two sides of b in the width direction of the laser line respectively, and a1 and c1 are two adjacent points on the two sides of b1 in the width direction of the laser line respectively; s3, setting the line width of a target laser line; s4, extracting the center point of the target laser ray: extracting the center of the laser ray by using a gray gravity center method; s5, extracting a target laser ray; the method can be applied to the 3D laser contourgraph to extract correct laser rays under the condition of interference, and serious loss of industrial production caused by inaccurate extraction of the laser rays is avoided. According to the invention, the laser line extraction precision is improved.

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 laser linewidth is an important parameter for characterizing the coherence properties of a single-frequency laser. The disclosure of this patent document provides techniques for characterizing laser spectral linewidths of single-frequency lasers in form of analytical formula in connection with the use of one or more Sigmoid functions of observation time by including various physical origins affecting the laser linewidths in addition to the natural linewidth caused by the spontaneous emission or quantum noise that can be described with an analytical expression known as the Schawlow-Townes-Henry formula. The disclosed methods for characterizing the laser linewidth caused by various factors in analytical formula can be advantageously used in various applications including designing an optical interferometer based sensing device using coherent laser light from a single-frequency laser.

The invention relates to the technical field of laser line width adjustment, and discloses an excimer laser and a line width narrowing module thereof, and the line width narrowing module comprises a housing, an accommodating cavity is formed in the housing, and the housing is provided with a light through hole for light to enter the accommodating cavity; the prism is arranged in the accommodating cavity and right faces the light through hole; the optical grating is also arranged in the accommodating cavity, and the light through hole, the prism and the optical grating are sequentially arranged in the incident direction of the light; and the blowing mechanism comprises a plurality of gas flow uniformizing devices arranged on one side of the prism and one side of the grating, and the gas flow uniformizing devices conduct blowing towards the prism and the grating. Water molecules and other factors causing optical component degradation can be effectively isolated, and the service life of the optical component is prolonged; and a large amount of heat is taken away through convection heat dissipation, so that the heat dissipation of the light-passing surface is better, the phenomenon of thermal instability is more difficult to occur, and the stability of excimer laser wavelength screening is more easily ensured.

The invention discloses an integrated optical signal receiver and method, particularly relates to the field of optical communication, is used for solving the problem of video stream transmission quality reduction caused by optical signal distortion in a low optical signal-to-noise ratio environment, and aims to eliminate cross coupling caused by a birefringence effect by constructing a dynamic polarization state transfer matrix. Generating a clear independent polarization state electric signal sequence; time-frequency domain processing is carried out on the electric signal sequences, linear phase noise caused by laser linewidth and phase deviation caused by an optical fiber nonlinear effect are compensated, and signals with higher phase accuracy are output; then, the signals are mapped to a four-dimensional constellation space, a clustering method is used for generating an adaptive judgment boundary, symbol judgment is optimized, and the anti-noise capability is improved; through cooperative work of an inner loop and an outer loop, system parameters are dynamically adjusted according to signal characteristics, and processing stability and adaptability are enhanced. And finally, performing soft decision decoding on the signal, improving the decoding accuracy in combination with phase residual correction, and outputting a reconstructed video data stream.

The invention discloses a narrow-linewidth double-frequency laser generation method, and belongs to the technical field of microwave photons. Two paths of optical signals generated by two semiconductor lasers with different wavelengths are injected into the same optical microcavity, the two paths of optical signals enter a self-injection locking state in different modes of the optical microcavity, and the optical microcavity can output narrow-linewidth double-frequency laser. The invention further discloses a narrow-linewidth double-frequency laser generating device and a photo-production microwave method and device. Two double-frequency lasers with different frequencies are locked on one optical microcavity through an original double-self-injection locking technology, the problem of phase noise of a double-frequency light source is effectively solved while the linewidth of the input laser is narrowed, common-mode noise caused by mode difference of the two lasers in a locking state is eliminated, and the dual-frequency light source has the advantages of being simple in structure and convenient to operate. And the traditional servo locking technology is not needed, so that the complexity of the system is simplified.

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 invention provides a laser linewidth measurement method and device based on digital decoherence, and is suitable for the technical field of laser linewidth analysis, and the method comprises the steps: dividing a to-be-measured laser source into first delay light and first reference light; performing digital de-coherence at least based on the first delay light and the first reference light to determine the frequency noise power spectral density of a to-be-measured laser corresponding to the to-be-measured laser source; and determining the laser line width of the to-be-measured laser according to the frequency noise power spectral density. The frequency noise power spectral density used for determining the laser line width is determined through digital decoherence, it is not required that the to-be-measured laser source and the auxiliary laser source have the same center wavelength, a complex physical optical fiber link is not needed so that introduction of a large amount of environmental noise can be avoided, and the flexibility, universality and precision of laser line width measurement can be improved.

The invention relates to a self-adaptive CKF phase noise compensation method in a coherent light OFDM system. The method comprises the following steps of: estimating a phase noise value of each OFDM symbol at a signal receiving end through known pilot frequency information, performing first phase noise fitting by using a second-order Hermite interpolation function, performing pre-judgment and secondary symbol partitioning on a compensated signal, performing second phase noise fitting by using an updated second-order Hermite interpolation function, and performing phase noise fitting on the compensated signal. And finally, the residual phase noise is suppressed by using the characteristics that the adaptive CKF can adaptively update the process noise and reduce the estimation error. Simulation results show that the method can effectively compensate CPE and ICI phase noise, meanwhile, the tolerance of the CO-OFDM system to the laser line width is also improved, and the performance of the system is improved.

The invention provides a start key type soliton micro-comb multi-line multiplexing system and a control method, and the system comprises a first soliton micro-comb generation and control module, a second soliton micro-comb generation and control module, a distance measurement module, a gas spectrum analysis module, a communication module and a processing module. The first soliton micro-comb generation and control module and the second soliton micro-comb generation and control module respectively generate a first soliton optical frequency comb and a second soliton optical frequency comb; the distance measurement module, the gas spectral analysis module and the communication module respectively output distance measurement data, gas spectral analysis data, a modulation signal and a local oscillation signal based on the first soliton optical frequency comb and the second soliton optical frequency comb; and the processing module receives the distance measurement data, the gas spectral analysis data, the modulation signal and the local oscillation signal and outputs a distance measurement result, a gas spectral analysis result and a modulation result. The system is simple in structure and operation, narrow in laser line width and excellent in performance, has no special requirements on the environment, and has reliability and robustness.

The invention relates to a narrow linewidth laser linewidth detection system based on spectrum reconstruction. The narrow linewidth laser linewidth detection system comprises a beam expanding collimation unit, an N-step etalon frequency discrimination unit, a beam splitting focusing unit, N point detectors and a multi-channel acquisition and data processing unit. The beam expanding and collimating unit is used for carrying out light beam collimation on incident measured laser, the N-step etalon frequency discrimination unit comprises N F-P cavities which are spliced into a multi-step etalon with a circular clear aperture, and the F-P cavities are used for respectively gating different spectral ranges of the measured laser and outputting parallel light with different energies. The beam splitting and focusing unit focuses the parallel light output by the N F-P cavities to the light sensing surfaces of the N point detectors respectively, and electric signals are formed through photoelectric conversion. And the multi-channel acquisition and data processing unit obtains a power measured value IM of each point detector, and calculates a power theoretical calculation value IjM of the N point detectors at the same time, thereby obtaining a line width value sigma of the measured single-frequency narrow-line-width laser. According to the invention, the problem that the 3dB bandwidth is difficult to directly read due to insufficient distinguishing capability of the existing frequency discriminator is solved.

The invention relates to the technical field of optical fiber lasers, and provides a middle-infrared band large-range accurate tunable optical fiber laser light source which adopts a large-range tunable 1 [mu] m laser pumping source to obtain ultra-wideband middle-infrared laser output larger than 1000 nm. Comprising a 1 [mu] m wave band tunable pulse seed source, an optical fiber amplifier module, an optical fiber end cap, an end cap coupling device, a hollow-core optical fiber and a small gas cavity, and the 1 [mu] m wave band tunable pulse seed source is a nanosecond pulse laser with the tuning range covering 1024-1080 nm. Based on the direct tuning of the pumping source of the 1 [mu] m wave band, the accurate tuning of the wavelength of the laser of 3 [mu] m-4 [mu] m is directly realized, the tuning is convenient, and a seed source does not need to be added. The pumping source at the 1 [mu] m waveband can obtain high-power laser output more easily, the damage threshold of the hollow-core optical fiber is high, and the mid-infrared output power can be effectively improved. The line width of the gas Raman laser is narrower, and the dispersion of the hollow-core optical fiber is small, so that the output mid-infrared laser has the characteristic of narrow line width.

A surface inspection system can be provided with a laser spot size or a laser line width that is selectable based on a measurable aspect of the objects under test that project upward or downward from a surface under test. The larger laser spot size or line width can be selected to cover a larger area of the surface under test at a time, which can increase scanning speed over the surface under test and enhance system measurement throughput.

The invention relates to the technical field of sensing, and discloses a demodulator chip with a phase noise compensation function and an optical fiber sound wave sensing system, and the demodulator chip comprises an optical port module, a first polarization filter, a beam splitter module, a modulator, a coherent receiving module and a phase noise extraction module. The optical port module is used for acquiring an incident laser signal, outputting probe light, acquiring scattered light and coupling with the delay optical fiber; the first polarization filter is connected with the optical port module; the beam splitter module is connected with the first polarization filter; the beam splitter module is connected with the optical port module through the modulator; the coherent receiving module is connected with the beam splitter module; the coherent receiving module is connected with the optical port module; the beam splitter module is connected with the phase noise extraction module, and the phase noise extraction module is connected to the delay optical fiber; the phase noise extraction module is used for extracting phase noise through a delay self-coherence mode; the requirement for the laser line width can be lowered, and the sensing performance under the same laser line width level is improved.

This invention provides a self-heterodyne detection system capable of stably and over long periods of time measuring broadband laser linewidths. [Solution] The present invention discloses a self-heterodyne detection system. The system may include a frequency comb light source that generates light, a photodetector that detects the light, an electrical spectrum analyzer connected to the photodetector that analyzes the frequency and wavelength of the light using the detection signal of the photodetector, an interferometer including an input coupler provided between the frequency comb light source and the photodetector to receive the light, a branch waveguide branched by the input coupler, and an output coupler connected to the branch waveguide, and a programmable filter provided in the branch waveguide to select the peak wavelength of the light.

The invention discloses a printing method for modulating the line width through double lasers, and belongs to the technical field of 3D printing. The method comprises the following steps that two sets of long-strip-shaped laser beams are set, and the scanning widths of the two sets of long-strip-shaped laser beams are both D; the to-be-printed pattern is divided into a plurality of printing blocks, and the width of the printing blocks is not larger than D; and when each printing block is printed, the sum of the power of the two sets of long-strip-shaped laser beams is modulated to be equal to the power needed by metal melting, the two sets of long-strip-shaped laser beams conduct synchronous scanning in the length direction of the printing blocks, and in the scanning process, according to the actual line width d of the current printing position, the laser overlapping area of the two sets of long-strip-shaped laser beams is adjusted, the width of the overlapping area is the same as the actual line width d at the current position, and the position of the overlapping area is overlapped with the position of the current to-be-printed part. According to the invention, thickness modulation can be carried out at microsecond-level time in the printing process, and when the same line is scanned, the size of the line width can be changed at will according to a printing pattern, so that the printing efficiency is improved.

The invention provides a laser linewidth measurement system and method based on a short optical fiber circulation self-heterodyne method, and can be applied to the technical field of laser measurement. The system comprises a to-be-measured laser used for outputting a to-be-measured laser signal; the Y-shaped single-mode optical fiber beam splitter is used for dividing a laser signal to be measured into two paths; the acousto-optic modulator is used for moving the frequency of one path of laser signal to be measured by a fixed amount and outputting a first optical signal; the optical fiber cyclic delay loop is used for circularly delaying the other path of laser signal to be measured and outputting a second optical signal; the Y-type single-mode optical fiber coupler is used for carrying out interference on the first optical signal and the second optical signal and outputting a third optical signal; the adjustable optical fiber attenuator is used for attenuating the third optical signal to the response range of the photoelectric detector and outputting a fourth optical signal; the photoelectric detector is used for converting the fourth optical signal into an electric signal; and the signal processing module is used for obtaining the line width of the to-be-measured laser according to the electric signal. Interference signals of different orders can be sampled and analyzed at the same time.

Disclosed is an optical feedback cavity ring-down spectroscopy system without phase control. The system comprises: a light source module, used for generating a laser of a predetermined wavelength; an optical feedback module, used for feeding back a part of the laser generated by the light source module into the light source module, and generating strong feedback or moderate feedback, so as to narrow the line width of the laser; an optical cavity module, used for increasing the effective action distance between the laser and a target detection substance, and exciting an optical cavity ring-down signal by means of achieving resonance between the laser and an optical cavity; a trigger light-cutting module, used to instantaneously cut off incident light of the optical cavity module to facilitate detection; a detection module, used to detect a transmitted optical signal outputted by the optical cavity module, convert the transmitted optical signal into a voltage signal, to be used as an optical cavity ring-down signal; and a data acquisition module, used to acquire the optical cavity ring-down signal outputted by the detection module, and perform exponential fitting on the optical cavity ring-down signal to obtain a ring-down 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 relates to a kind of multi-channel short delay optical fiber laser linewidth measurement methods, the laser to be measured is divided into multiple channels by coupler after passing through optical isolator, wherein the first group of optical signals are frequency-shifted by acousto-optic modulator, the remaining optical signals are coupled with the first group of frequency-shifted optical signals after passing through different lengths of short delay optical fiber, converted into optical signals after input to photodetector, finally output to oscilloscope or spectrum analyzer to extract the power difference of power spectrum first-order envelope peak and second-order envelope peak, and finally the linewidth parameter of the laser to be measured is obtained by correlation processing. The application can effectively reduce the length of delay optical fiber, reduce the sensitivity of the system to environmental vibration interference by 100 times, and the multi-channel information collection of different lengths of delay optical fiber can obtain the average level of the laser linewidth output in a time period and under a working state at one time, which is beneficial to eliminate the accidental error influence in linewidth measurement.

A method for determining a target displacement amount. The method comprises: receiving a sample image collected in real time (S302); determining a target linewidth difference between a laser linewidth in the sample image and a target linewidth threshold value (S304), wherein the target linewidth threshold value is a laser linewidth value collected by a laser detection device at a focusing position; on the basis of a preset relationship between a linewidth difference and a displacement amount, determining a target displacement amount which corresponds to the target linewidth difference (S306), wherein the relationship between the linewidth difference and the displacement amount is obtained by means of fitting, in a data fitting manner, a laser linewidth difference and a displacement interval corresponding to the laser linewidth difference, and the data fitting manner is a data fitting manner corresponding to an original laser form of the laser detection device; and on the basis of the target displacement amount, moving to the focusing position (S308). The efficiency and precision for determining a target displacement amount can be improved on the basis of a known relationship between a laser linewidth and a displacement amount. Further provided are an apparatus for determining a target displacement amount, and a laser detection device, a storage medium and a computer program product.

The invention belongs to the technical field of optical engineering, and discloses a dispersion-based one-way optical fiber communication and distributed sensing depth fusion positioning method and system, a terminal and a storage medium, and the method comprises the steps: inputting optical signals with different wavelengths into corresponding modulators, enabling the modulated optical signals to enter the same optical fiber through a wavelength division multiplexer, and enabling the optical signals to enter the same optical fiber; transmitting to a receiving end in a one-way transmission mode; extracting an optical phase of an optical signal in the receiving end based on an autocorrelation technology, and analyzing a range-resolved vibration signal, a vibration amplitude and a vibration frequency; and calculating the time difference of the vibration signal according to the distance resolution vibration signal, the vibration amplitude and the vibration frequency, and calculating the position of vibration according to the time difference. According to the invention, the forward transmission continuous wave light is used for replacing weak backward scattering light, so that an ultra-long sensing distance is realized, and vibration positioning can be realized without an ultra-narrow laser line width by adopting self-coherent demodulation, so that the cost is reduced, and the positioning mode is simplified.

The utility model discloses a laser line width measuring device based on a short optical fiber, relates to the technical field of delayed self-heterodyne measurement, and aims to solve the problem that a laser line width measuring result is inaccurate due to the existence of 1 / f frequency noise in the conventional delayed self-heterodyne technology. In the device, laser to be measured is divided into two laser beams through the first coupler, one laser beam enters the acousto-optic modulator, the other laser beam enters the gear-adjustable short optical fiber delay line device, and the laser emitted from the acousto-optic modulator and the laser emitted from the gear-adjustable short optical fiber delay line device are combined through the second coupler and then are transmitted to the second coupler. And the high-speed photoelectric detector is used for detecting, and detection data is sent to the electric spectrum analyzer. The shift-adjustable short optical fiber delay line device has a plurality of shifts, different shifts correspond to delay optical fibers with different lengths, 1 / f frequency noise can be effectively avoided, the laser line width measurement precision is improved, the laser line width measurement range is expanded, and the shift-adjustable short optical fiber delay line device is suitable for measurement of lasers with various line widths.

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, a grating optical waveguide substrate, an 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 grating optical waveguide substrate.

The utility model provides a frequency-doubled laser linewidth narrowing device. The device comprises a pumping module and a laser resonant cavity, the pumping module is used for providing linearly polarized light in a specific polarization direction to a light path; the laser resonant cavity is internally provided with a gain medium, at least one birefringence optical filter and a frequency doubling crystal which are sequentially arranged along an optical path, and the at least one birefringence optical filter is inserted into the optical path at a Brewster angle; wherein the linearly polarized light is focused in the gain medium, the central wavelength of the linearly polarized light is the same as the absorption peak wavelength of the gain medium, and the polarization direction of the linearly polarized light is the same as the maximum absorption direction of the gain medium. According to the invention, the birefringence optical filter (group) inserted into the laser resonant cavity can be specifically adjusted, so that narrow-band filtering can be conveniently and quickly realized in various intracavity frequency doubling lasers, and compared with the prior art, the introduced power loss is relatively small.

The present invention belongs to the field of artificial intelligence, and relates to a method, device, computer device and storage medium for extracting the center point of a laser line. The method includes: obtaining a laser line picture; analyzing the frequency domain property and edge property of the laser picture; extracting high-frequency components from the frequency domain image as high-frequency features, extracting edge points from the edge detection result as edge features, using the extracted high-frequency features and edge features as inputs to construct a segmentation model, applying the trained segmentation model to segment the original laser line picture, binarizing the segmentation result to obtain a mask picture containing only the laser line; obtaining laser line width information according to the mask picture; using KMEANS to analyze the region division of the laser line width information and performing threshold segmentation to obtain the optimal demarcation point of the laser line width. It enhances the fineness and robustness of extracting the center point of the laser line; improves the accuracy and adaptability.

The application discloses a narrow-linewidth laser external cavity coupling system and method based on linewidth test feedback, adopts a self-feedback mechanism to perform external cavity coupling, wherein through optical power real-time feedback, the laser can be ensured to be in the best working state when measuring the linewidth, so that the accuracy of the linewidth measurement can be improved, and reliable data can be provided for subsequent external cavity position adjustment; after the linewidth measurement is completed, the external cavity clamp displacement table can be controlled to adjust the position of the external cavity of the narrow-linewidth laser according to the linewidth, until the linewidth of the laser output by the external cavity reaches a preset target, and the best coupling position of the external cavity can be determined; thus, the application comprehensively considers the optical power and the laser linewidth to perform external cavity coupling, can ensure that the actual performance meets the design index, ensures the parameter consistency, and the whole process is fully automated, without the intervention of personnel, effectively avoiding the subjective influence of the operator, so that the process stability and the production efficiency are improved.

The invention relates to the technical field of laser, and provides a wide-tuning narrow-linewidth mid-infrared light parameter laser generation device, which comprises a pump laser oscillation cavity and an optical parameter laser oscillation cavity, and is characterized in that the pump laser oscillation cavity is used for generating pump laser; the pumping laser oscillation cavity comprises a pumping laser gain module, a pulse modulation module, a line width narrowing module, an optical isolation module, a first reflecting mirror and at least two second reflecting mirrors; the optical parametric laser oscillation cavity comprises an optical parametric oscillation nonlinear crystal module, a line width narrowing module, a first reflecting mirror and at least two third reflecting mirrors, the pumping laser oscillation cavity and the optical parameter laser oscillation cavity are both annular cavities and are nested with each other. The annular pump laser oscillation cavity and the optical parameter laser oscillation cavity are nested with each other, and high-stability simultaneous narrowing control of the pump laser line width and the wide tuning optical parameter signal laser line width is realized by using the same line width narrowing module, so that the requirement of wide tuning narrow line width intermediate infrared idler frequency light stable output is met.

The present invention discloses a gas Raman detection device based on a semiconductor laser self-locked enhancement cavity, belonging to the field of gas detection. The device comprises a laser unit, a laser linewidth narrowing unit, a self-locked enhancement cavity unit, and a Raman scattered light collection unit. A mode-matching lens is used to tilt the laser beam emitted by the semiconductor laser into an enhanced external cavity. The laser beam is then repeatedly reflected within a confocal spherical mirror cavity formed by a first spherical reflector M1 and a second spherical reflector M2. Part of the laser light is emitted from the external cavity and returns to the semiconductor laser, forming optical feedback, causing the semiconductor laser and the enhanced external cavity to resonate in frequency. The device eliminates the need for enhanced cavity length feedback, resulting in a simple and stable optical path layout, which can simultaneously reduce optical path complexity and device cost. The device boasts an external cavity laser power of tens of watts, and the laser linewidth narrowed by the laser linewidth narrowing unit enables the Raman signal spectrum to have higher resolution and intensity.

This invention discloses a method and apparatus for detecting the linewidth of a narrow-linewidth laser. The method includes acquiring data information pre-collected using a data acquisition card; preprocessing the data information using a cumulative averaging algorithm; performing a fast Fourier transform on the preprocessed time-domain data information; processing the data using a moving average algorithm; fitting the moving averaged data using an L-M algorithm; and detecting the linewidth of the fitted data using a time-delayed self-heterodyne method to calculate the laser linewidth data. This invention uses a time-delayed fiber beat frequency method to measure the linewidth of a narrow-linewidth laser, which greatly enhances the accuracy of laser linewidth measurement while reducing the number of components used. This method uses a data acquisition card for data acquisition, fast Fourier transform for analysis and processing, and moving average and L-M algorithms for data processing, reducing costs while accurately detecting narrower laser linewidths.