CN-122016260-A - Laser linewidth measuring device and method

CN122016260ACN 122016260 ACN122016260 ACN 122016260ACN-122016260-A

Abstract

The application provides a device and a method for measuring the linewidth of a laser, which can be applied to the technical field of laser. The measuring device comprises a filter, a detector and a processor, wherein the filter is configured to have a tunable transmission center wavelength, so that the variation of the transmission center wavelength covers the linewidth of a laser to be measured, the filter filters output laser of the laser to be measured, the transmission spectrum of the filter has a preset linewidth and the preset linewidth, the output spectrum of the laser has a preset linewidth, the detector is configured to detect the filtered laser to obtain power of the output laser transmitted through the filter at different transmission center wavelengths, the processor is configured to fit each transmission center wavelength and the power corresponding to each transmission center wavelength based on the preset linewidth to generate a power spectrum, and the linewidth of the output spectrum of the laser to be measured is determined based on the linewidth of the power spectrum and the preset linewidth of the transmission spectrum.

Inventors

ZHANG CHEN
PAN JIANWEI
LI YANG
LI CHENGLIN
HAN LIYING
QIU BOYANG
REN JIGANG
YIN JUAN
LIAO SHENGKAI
PENG CHENGZHI

Assignees

合肥国家实验室
中国科学技术大学

Dates

Publication Date: 20260512
Application Date: 20260413

Claims (10)

1. A measuring device for a linewidth of a laser, the measuring device comprising: A filter configured to have a transmission center wavelength that can be tuned such that a variation of the transmission center wavelength covers a linewidth of a laser to be measured, filtering an output laser of the laser to be measured, wherein a transmission spectrum of the filter has a predetermined linewidth and a predetermined linewidth, and an output spectrum of the laser to be measured has the predetermined linewidth; the detector is configured to detect the filtered laser to obtain the power of the output laser transmitted through the filter under different transmission center wavelengths; A processor configured to: Fitting each transmission center wavelength and power corresponding to each transmission center wavelength based on the preset line type to generate a power spectrum; and determining the line width of the output spectrum of the laser to be tested based on the line width of the power spectrum and the preset line width of the transmission spectrum.
2. The measurement device of claim 1, wherein the predetermined line shape comprises a lorentz line shape, the line width is characterized by a full width at half maximum, and the processor is configured to: Fitting each transmission center wavelength and power corresponding to each transmission center wavelength based on the Lorentz line type to generate a Lorentz power spectrum; And subtracting the full width half maximum of the transmission spectrum from the full width half maximum of the Lorentz power spectrum to obtain the full width half maximum of the output spectrum of the laser to be tested.
3. The measurement device of claim 1, wherein the predetermined line shape comprises a gaussian line shape, the line width is characterized by a full width at half maximum, the processor configured to: fitting each transmission center wavelength and the power corresponding to each transmission center wavelength based on Gaussian line type to generate Gaussian power spectrum; And obtaining the square root of the difference between the square of the full width half maximum of the Gaussian power spectrum and the square of the full width half maximum of the transmission spectrum, and obtaining the full width half maximum of the output spectrum of the laser to be tested.
4. A measurement device according to any one of claims 1 to 3, wherein the parameters of the filter comprise tuning parameters, the filter being configured to: and adjusting the tuning parameter to adjust the value of the transmission center wavelength so that the variation of the transmission center wavelength covers the linewidth of the laser to be tested, and filtering the output laser of the laser to be tested.
5. The measurement device of claim 4, wherein the tuning parameter comprises temperature.
6. The measurement device of claim 1, wherein the predetermined linewidth of the transmission spectrum of the filter is smaller than the linewidth of the output spectrum of the laser under test.
7. A method for measuring linewidth of a laser, the method comprising: Tuning the transmission center wavelength of a filter so that the variation of the transmission center wavelength covers the linewidth of the laser to be tested, and filtering the output laser of the laser to be tested, wherein the transmission spectrum of the filter has a preset linewidth and the output spectrum of the laser to be tested has the preset linewidth; detecting the filtered laser by using a detector to obtain the power of the output laser transmitted through the filter under different transmission center wavelengths; Fitting each transmission center wavelength and power corresponding to each transmission center wavelength based on the preset line type to generate a power spectrum; and determining the line width of the output spectrum of the laser to be tested based on the line width of the power spectrum and the preset line width of the transmission spectrum.
8. The method of measuring according to claim 7, wherein the predetermined line type comprises a lorentz line type; Fitting each transmission center wavelength and the power corresponding to each transmission center wavelength based on the predetermined line shape to generate a power spectrum, including: Fitting each transmission center wavelength and power corresponding to each transmission center wavelength based on the Lorentz line type to generate a Lorentz power spectrum; the determining the line width of the output spectrum of the laser to be measured based on the line width of the power spectrum and the predetermined line width of the transmission spectrum includes: And subtracting the full width half maximum of the transmission spectrum from the full width half maximum of the Lorentz power spectrum to obtain the full width half maximum of the output spectrum of the laser to be tested.
9. The measurement method according to claim 7, wherein the predetermined line shape includes a Gaussian line shape; Fitting each of the transmitted center wavelengths and the power corresponding to each of the transmitted center wavelengths based on the predetermined line shape, to generate a power spectrum, including: fitting each transmission center wavelength and the power corresponding to each transmission center wavelength based on Gaussian line type to generate Gaussian power spectrum; the determining the line width of the output spectrum of the laser to be measured based on the line width of the power spectrum and the predetermined line width of the transmission spectrum includes: And obtaining the square root of the difference between the square of the full width half maximum of the Gaussian power spectrum and the square of the full width half maximum of the transmission spectrum, and obtaining the full width half maximum of the output spectrum of the laser to be tested.
10. The measurement method of claim 7, wherein the parameters of the filter include tuning parameters; the tunable transmission center wavelength of the filter is tuned, so that the variation of the transmission center wavelength covers the linewidth of the laser to be tested, and the filtering of the output laser of the laser to be tested comprises the following steps: and adjusting the tuning parameter to adjust the value of the transmission center wavelength so that the variation of the transmission center wavelength covers the linewidth of the laser to be tested, and filtering the output laser of the laser to be tested.

Description

Laser linewidth measuring device and method Technical Field At least one embodiment of the application relates to the technical field of lasers, in particular to a device and a method for measuring the linewidth of a laser. Background The laser is a device capable of generating high-coherence, monochromaticity and collimation light beams based on the stimulated radiation principle, and is widely applied to various fields such as optical communication, spectrum analysis, optical measurement, quantum information, laser radar, biomedical imaging and the like. With the advanced application of laser technology in the above fields, high performance lasers have become an indispensable core device for various fields. The comprehensive performance of the laser is scientifically evaluated, the system characterization is carried out through a plurality of parameters, the linewidth of the laser is a core index for measuring the spectral purity and the coherence characteristic of the laser, the accurate measurement of the index is realized, and the method plays an important role in improving the performance of the laser. However, the method for measuring the linewidth of the laser in the prior art has various disadvantages, such as complex device and limited application range. Disclosure of Invention According to a first aspect of the present application, there is provided a measuring apparatus for a laser linewidth, the measuring apparatus including a filter configured to have a transmission center wavelength capable of tuning so that a variation of the transmission center wavelength covers a linewidth of a laser to be measured, filtering an output laser of the laser to be measured, wherein a transmission spectrum of the filter has a predetermined linewidth and a predetermined linewidth, and an output spectrum of the laser to be measured has the predetermined linewidth, a detector configured to detect the filtered laser to obtain powers of the output laser transmitted through the filter at different transmission center wavelengths, and a processor configured to fit each of the transmission center wavelengths and powers corresponding to each of the transmission center wavelengths based on the predetermined linewidth, generating a power spectrum, and determining a linewidth of the output spectrum of the laser to be measured based on the linewidth of the power spectrum and the predetermined linewidth of the transmission spectrum. According to the embodiment of the application, the preset line type comprises a Lorentz line type, the line width is represented by a full width at half maximum, the processor is configured to fit each transmission center wavelength and power corresponding to each transmission center wavelength based on the Lorentz line type to generate a Lorentz power spectrum, and the full width at half maximum of the Lorentz power spectrum is subtracted from the full width at half maximum of the transmission spectrum to obtain the full width at half maximum of the output spectrum of the laser to be tested. According to an embodiment of the application, the predetermined line shape comprises a Gaussian line shape, the line width is represented by a full width at half maximum, the processor is configured to fit each of the transmission center wavelengths and the power corresponding to each of the transmission center wavelengths based on the Gaussian line shape to generate a Gaussian power spectrum, and square root of the difference between the square of the full width at half maximum of the Gaussian power spectrum and the square of the full width at half maximum of the transmission spectrum is obtained to obtain the full width at half maximum of the output spectrum of the laser to be tested. According to the embodiment of the application, the parameters of the filter comprise tuning parameters, and the filter is configured to adjust the value of the transmission center wavelength by adjusting the tuning parameters so that the variation of the transmission center wavelength covers the line width of the laser to be tested and filter the output laser of the laser to be tested. According to an embodiment of the application, the tuning parameter comprises temperature. According to an embodiment of the present application, the predetermined line width of the transmission spectrum of the filter is smaller than the line width of the output spectrum of the laser to be measured. The second aspect of the application provides a method for measuring the linewidth of a laser, which comprises the steps of tuning the transmission center wavelength of a filter so that the change amount of the transmission center wavelength covers the linewidth of the laser to be measured, filtering output laser of the laser to be measured, wherein the transmission spectrum of the filter has a preset linewidth and the preset linewidth, the output spectrum of the laser to be measured has the preset linewidth, detecting the filtered laser by a det