Spectrometer power calibration apparatus and method
By integrating modules such as lasers into the spectrometer, automated power calibration is achieved, solving the problems of complexity and inconvenience in existing spectrometer calibration systems. This improves the efficiency and accuracy of power calibration for spectrometers and is suitable for regular maintenance of spectrometers.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA ELECTRONIS TECH INSTR CO LTD
- Filing Date
- 2023-04-17
- Publication Date
- 2026-06-12
AI Technical Summary
Existing spectrometer power calibration systems are complex and inconvenient to move, the calibration process is cumbersome, and the calibration coefficients become inapplicable after long-term use, requiring return to the factory for repair, resulting in low efficiency and reduced accuracy.
A power calibration device integrated into a spectrometer was designed, including a laser, an adjustable optical attenuator, a beam splitter, an optical switch, a drive circuit, a power adjustment module, a power monitoring module, and a calibration coefficient calculation module. This device enables automated power calibration. The calibration coefficient is calculated by fitting a cubic polynomial, and considering the influence of wavelength deviation, an error curve is introduced for secondary calibration.
It enables periodic automated power calibration of the spectrometer, simplifies the calibration process, improves power accuracy, reduces errors, and ensures the power accuracy and continuity of the spectrometer during long-term use.
Smart Images
Figure CN116358702B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of spectrometer calibration technology, and in particular to a spectrometer power calibration device and method. Background Technology
[0002] A spectroscope is a scientific instrument that decomposes complex light into spectral lines. It consists of prisms or diffraction gratings and measures the light reflected from the surface of an object. Its working principle involves separating the light beam emitted from a light source according to different wavelengths, measuring the intensity of the spectral lines using various photoelectric detection devices, and obtaining a spectral curve. Based on this spectral curve, parameters such as chromaticity coordinates, color temperature, color rendering index, luminous flux, and radiant flux are calculated. However, due to the influence of multiple factors such as the diffraction efficiency of the grating, the quantum efficiency of the detector, and the reflection or transmission efficiency of the lenses, the relationship between the voltage value of the spectral curve and the incident light power obtained by simple function calculations has a certain error. That is, the calculation of the incident light power value based on the voltage value of the obtained spectral curve has a significant error. Therefore, it is necessary to calibrate the spectroscope power to ensure that the incident light power value measured by the spectroscope is consistent with the incident light power value measured using a standard optical power meter, thus guaranteeing the accuracy of the incident light power during spectroscope testing.
[0003] In the prior art, Chinese Patent Application No. CN201510731548.8 discloses a vacuum ultraviolet imaging spectrometer calibration device, including a vacuum ultraviolet light source for generating ultraviolet light of different wavelengths, a vacuum ultraviolet light processing module for splitting and homogenizing the ultraviolet light, a vacuum ultraviolet target module for providing a feature target, converting the ultraviolet light into ultraviolet light with corresponding characteristics, and sending it to a standard ultraviolet imaging spectrometer or a calibrated ultraviolet imaging spectrometer, a standard ultraviolet imaging spectrometer for receiving the ultraviolet light output from the target module and outputting standard light radiation power, and a control module for receiving the standard light radiation power and the light radiation power output from the calibrated ultraviolet imaging spectrometer and outputting calibration results, thereby realizing the calibration of the vacuum ultraviolet imaging spectrometer before launch and ensuring the normal operation of the vacuum ultraviolet imaging spectrometer on the space station; Chinese Patent Application No. CN201610248470.9 discloses a light The spectrometer and its calibration method include an incident optical unit, an incident slit, a dispersion unit for dispersing incident light, an array detector for receiving the dispersed light, and a wideband detector. The wideband detector receives the zero-order beam formed by diffraction by the dispersion unit. By placing a color filter matching the V(λ) curve in front of the photoelectric conversion element of the wideband detector, the linearity of the array detector is corrected using the photometric information measured by the wideband detector, and the absolute radiance to be measured is obtained. The spectral mismatch is corrected using the relative spectral power distribution measured by the array detector, thereby improving the photometric measurement accuracy. The paper "Research on Relative Spectral Power Response Test Technology of Multispectral Imaging Spectrometer" discloses a power response calibration method and test device for a visible to near-infrared imaging spectrometer. The imaging spectrometer is directly calibrated using a standard light source with a known spectral power distribution, and the spectral power response is directly given based on the output signal of each pixel.
[0004] In the above-mentioned prior art, (1) the test system built with external light source, optical attenuator, optical power meter, etc. is used for calibration. The test system is complex and large in size, extremely inconvenient to transport, and requires manual calibration, which is complicated and inefficient; (2) the existing power calibration method is usually only calibrated when the spectrometer leaves the factory. When the spectrometer has been used for a long time, the measured power value changes and the power calibration coefficient is no longer applicable. It needs to be returned to the factory for repair and recalibration, which is time-consuming and laborious. Summary of the Invention
[0005] To address the shortcomings of the prior art, this invention provides a spectrometer power calibration device and method. The power calibration device can be integrated into the spectrometer to enable regular maintenance and power calibration of the spectrometer, ensuring the power accuracy of the spectrometer during long-term use; it achieves automated power calibration, reduces the complexity of power calibration, simplifies the power calibration process, and results in more accurate power values of the calibrated spectrometer.
[0006] In a first aspect, this disclosure provides a spectrometer power calibration device, comprising: a laser, an adjustable optical attenuator, a beam splitter, an optical switch, a drive circuit, a power adjustment module, a power monitoring module, and a calibration coefficient calculation module;
[0007] The power adjustment module controls the drive circuit and the adjustable optical attenuator. It drives the laser to generate monochromatic light by controlling the drive circuit and adjusts the attenuation value of the monochromatic light generated by the laser by controlling the adjustable optical attenuator. The beam splitter splits the input monochromatic light into two beams: a reference beam and a calibration beam. The reference beam enters the power monitoring module, which acquires the reference power value of the reference beam. The calibration beam enters the spectrometer through the second channel of the optical switch. The calibration coefficient calculation module calculates the power calibration coefficient based on the reference power value of the reference beam and the acquired power value of the spectrometer calibration beam.
[0008] A further technical solution is that the operation process of the spectrometer power calibration device includes:
[0009] The laser, acting as a reference light source, generates monochromatic light for power calibration under the drive of the driving circuit. The monochromatic light passes through an adjustable optical attenuator and then enters a beam splitter, splitting into a reference beam and a calibration beam. The reference beam enters the power monitoring module to obtain the reference power value of the reference beam. The calibration beam enters the spectrometer's beam splitting module through the second channel of the optical switch. After being split by the beam splitting module, it is incident on the detector for photoelectric conversion. Then, the electrical signal is acquired by the data acquisition module, and the power value is obtained through the FPGA. The calibration coefficient calculation module calculates the power calibration coefficient based on the reference power value of the reference beam and the power value of the calibration beam.
[0010] The spectrometer consists of a spectrometer, ...
[0011] A further technical solution also includes: a calibration coefficient storage module, which stores the power calibration coefficients calculated by the calibration coefficient calculation module, and also stores the original response rate curve and wavelength deviation curve.
[0012] Secondly, this disclosure provides a spectrometer power calibration method, implemented based on the aforementioned spectrometer power calibration device, comprising:
[0013] Step 1: Turn on the laser's drive circuit and set the initial calibration power value P0 of the initial setting to the maximum power value P through the power adjustment module. max Monochromatic light of corresponding power is generated by a laser;
[0014] Step 2: The adjustable optical attenuator adjusts the input monochromatic light power value by setting the attenuation value. The adjusted monochromatic light is split into two beams, a reference beam and a calibration beam, by the beam splitter. The power monitoring module is turned on to monitor the reference light power value and determine whether the reference light power value meets the judgment condition. If it does, proceed to the next step.
[0015] Step 3: The calibration light enters the spectrometer's dispersive module through the second channel of the optical switch. The dispersive module begins scanning. After being dispersed, the calibration light is incident on the detector surface. The data acquisition module and FPGA generate a spectral curve. Based on the spectral curve, a peak search algorithm is used to locate the peak wavelength position, and then the voltage value at the peak is determined.
[0016] Step 4: After the scan is completed, determine whether the reference optical power value of the current gear is equal to the minimum power value. If not, repeat steps 2 to 4 until the condition is met. If so, the calibration coefficient calculation module obtains the reference optical power value and test voltage value of each gear and calculates the power calibration coefficient.
[0017] In a further technical solution, the determination condition for step 2 is:
[0018] The power adjustment module adjusts the power according to the test reference optical power value P. i and the power setting value P of the current gear s Make a judgment if the test reference optical power value P i Equal to power setpoint P s If the result is positive, proceed to the next step; otherwise, control the adjustable optical attenuator to adjust the monochromatic light power value by an attenuation value α until the test reference light power value P is reached. i Ultimately equal to the power setpoint P s .
[0019] In a further technical solution, step 3 involves repeating the scan multiple times to obtain the peak value V searched after the j-th scan. ij The voltage value V at the peak of the i-th gear is obtained by averaging. i , where j = 1, 2, 3, ..., M, i = 1, 2, 3, ..., N.
[0020] In a further technical solution, in step 4, the reference optical power value P of the i-th level is determined. i Is it equal to the minimum power value P? min If not, then repeat steps 2 to 4 in a loop, and calculate the voltage value V at the peak value of the i-th gear corresponding to the reference optical power value of the (i+1)-th gear. i+1 Conversely, the calibration coefficient calculation module obtains the reference optical power value and test voltage value for each of the N ranges (i.e., the power monitoring module, the spectrometer's data acquisition module, and the FPGA) to calculate the power calibration coefficient.
[0021] Further technical solutions include calculating the power calibration coefficient, including:
[0022] The calibration power values P of N levels i With the test voltage value V i The power calibration coefficient is calculated by performing a cubic polynomial fit using the calibration coefficient calculation module.
[0023] Further technical solutions include: performing secondary calibration based on the calculated spectral power across the entire wavelength range.
[0024] A further technical solution, the secondary calibration includes:
[0025] The error curve δ(λ) of the introduced wavelength is used to calculate the displayed power value P of the entire spectrum from the power value at the current test wavelength point. D (λ), the formula is:
[0026] P D (λ)=f[λ+δ(λ)]*{a*V(λ) 3 +b*V(λ) 2 +c*V(λ)+d};
[0027] Where a, b, c, and d are power calibration coefficients, V(λ) is the test voltage value at wavelength λ, and the error curve δ(λ) is obtained from the error after fitting during wavelength calibration.
[0028] The above one or more technical solutions have the following beneficial effects:
[0029] 1. This invention provides a spectrometer power calibration device, which consists of a drive circuit, a DFB laser, an adjustable optical attenuator, a beam splitter, an optical switch, a power adjustment module, a power monitoring module, a calibration coefficient calculation module, and a calibration coefficient storage module. Each module is small in size and light in weight, and can be integrated inside the spectrometer. It can be used for the regular maintenance and power calibration of the spectrometer, ensuring the power accuracy of the spectrometer during long-term use.
[0030] 2. In this invention, the power adjustment module combined with the power monitoring module can adjust the laser driving voltage and the attenuation value of the adjustable optical attenuator, and can automatically calibrate the power values at different levels, reducing the complexity of power calibration and simplifying the power calibration process.
[0031] 3. This invention provides a method for power calibration of a spectrometer. The power calibration coefficients a, b, c, and d are calculated by cubic polynomial fitting, which can reduce the error between the test value and the actual value and improve the power linearity index of the entire spectrometer. At the same time, the influence of wavelength deviation is considered when calculating the spectral power, and a wavelength error function is introduced, which can effectively eliminate the deviation in spectral power calculation caused by wavelength deviation. Since the fitting curve itself is continuous, there is no power gap phenomenon, which can improve the linearity of spectral power and ensure the continuity of power.
[0032] 4. In this invention, the optical switch is switched to the first channel during testing and to the second channel during calibration. The test light and calibration light do not interfere with each other, enabling automated power calibration. Attached Figure Description
[0033] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.
[0034] Figure 1 This is a schematic diagram of the spectrometer power calibration device according to Embodiment 1 of the present invention;
[0035] Figure 2 This is a flowchart of the spectrometer power calibration method described in Embodiment 2 of the present invention;
[0036] Figure 3 This is a power offset diagram caused by wavelength deviation in Embodiment 2 of the present invention;
[0037] Figure 4 This is a power offset diagram caused by the adjusted wavelength deviation in Embodiment 2 of the present invention. Detailed Implementation
[0038] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.
[0039] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.
[0040] Example 1
[0041] To address the problems existing in the background art and enable the spectrometer to maintain high power accuracy during testing and after prolonged use, this embodiment provides a spectrometer power calibration device, such as... Figure 1 As shown, the system includes: a laser, an adjustable optical attenuator, a beam splitter, an optical switch, a driving circuit, a power adjustment module, a power monitoring module, and a calibration coefficient calculation module. In this embodiment, a DFB (Distributed Feedback Laser) laser is used as the reference light source. The power adjustment module controls the driving circuit and the adjustable optical attenuator. The driving circuit drives the DFB laser to generate monochromatic light, and the attenuation value of the monochromatic light generated by the DFB laser is adjusted by controlling the optical attenuator, i.e., adjusting the DFB laser driving voltage and the attenuation value of the adjustable optical attenuator. This achieves automatic calibration of the monochromatic light power value at different levels, realizing the control of the generated monochromatic light power. A 50:50 beam splitter is used to divide the input monochromatic light into two beams: 50% reference light and 50% calibration light. The power monitoring module is used to obtain the reference power value of the reference light, and the calibration coefficient calculation module is used to calculate the power calibration coefficient based on the reference power value of the reference light and the obtained calibration light power value.
[0042] The working principle of the spectrometer power calibration device is as follows: A DFB laser, acting as a reference light source, generates monochromatic light for power calibration under the drive of the driving circuit. The monochromatic light passes through an adjustable optical attenuator and then enters a 50:50 beam splitter, splitting into two beams: a 50% reference beam and a 50% calibration beam. The reference beam enters the power monitoring module, which is used to obtain the reference power value of the reference beam, which is the actual optical power. In this embodiment, a 1×2 optical switch is used. When the 1×2 optical switch is switched to the second channel, the calibration beam enters the spectrometer's beam splitting module through the second channel of the 1×2 optical switch. After being split by the beam splitting module, the beam is incident on the detector for photoelectric conversion, converting the optical signal into an analog electrical signal. The analog electrical signal is then acquired by the data acquisition module and converted into a digital electrical signal. A spectral curve is then formed by the FPGA (Field-Programmable Gate Array). The power value of the calibration beam is obtained based on the spectral curve (the voltage value of the calibration beam can also be obtained here). The calibration coefficient calculation module calculates the power calibration coefficient based on the reference power value of the reference beam and the power value of the calibration beam. The aforementioned spectrometer consists of a spectrometer composed of a spectrometer module, a detector, a data acquisition module, and an FPGA.
[0043] Considering that wavelength shift will also lead to errors in spectral power calculation, the power calibration device proposed in this embodiment also includes a calibration coefficient storage module. This calibration coefficient storage module is used to store the power calibration coefficients calculated by the calibration coefficient calculation module, and also stores the original response rate curve and wavelength deviation curve. When testing the power of the light under test using a spectrometer, the 1×2 optical switch is switched to the first channel. The light under test enters the beam splitting module through the input optical interface and the first channel of the 1×2 optical switch. After diffraction and beam splitting, it passes through the detector. The data acquisition module collects the photoelectric signal under test and extracts the power calibration coefficient from the calibration coefficient storage module, thereby calculating the calibrated power value of the light under test.
[0044] The power calibration device described in this embodiment consists of a drive circuit, a DFB laser, an adjustable optical attenuator, a 50:50 beam splitter, a 1×2 optical switch, a power adjustment module, a power monitoring module, a calibration coefficient calculation module, and a calibration coefficient storage module. Each module is small in size and light in weight, and can be integrated into the spectrometer. It can be used for the regular maintenance and power calibration of the spectrometer, ensuring the power accuracy of the spectrometer during long-term use.
[0045] Example 2
[0046] Based on the above embodiments, this embodiment provides a spectrometer power calibration method, such as... Figure 2 As shown, it includes:
[0047] Step S1: Calibrate the spectrometer power. First, switch the 1×2 optical switch to the second channel, turn on the drive circuit of the DFB laser in the power calibration device, and set the initial calibration power value P0 of the initial setting to the maximum power value P through the power adjustment module. max The DFB laser is driven by a driving circuit to generate the initial calibration power value P0 for the initial setting. max Monochromatic light;
[0048] Step S2: Monochromatic light is input to an adjustable optical attenuator. The power adjustment module controls the adjustable optical attenuator to adjust the monochromatic light power value by an attenuation value α. The adjusted monochromatic light is split into two beams, a reference beam and a calibration beam, by a 50:50 beam splitter. The power monitoring module is then activated to monitor the reference beam power value P. i Where i = 1, 2, 3, ..., N, and N represents the number of power levels (the power level refers to the power value level; for example, each 10dB increase or decrease in power value constitutes one level). The power adjustment module adjusts the power based on the test reference optical power value P. i and the power setting value P of the current gear s Make a judgment if the test reference optical power value P i Equal to power setpoint P sIf the result is positive, proceed to the next step; otherwise, control the adjustable optical attenuator to adjust the monochromatic light power value by an attenuation value α until the test reference light power value P is reached. i Ultimately equal to the power setpoint P s ;
[0049] Specifically, each power setting has a corresponding power setting value. Taking the first setting as an example, monochromatic light is input to an adjustable optical attenuator. The power adjustment module controls the adjustable optical attenuator to adjust the monochromatic light power value by an attenuation value α. The adjusted monochromatic light is split into two beams, a reference beam and a calibration beam, by a 50:50 beam splitter. The power monitoring module is activated to monitor the reference light power value P1 = P0 - α. The power adjustment module adjusts the power based on the test reference light power value P1 and the power setting value P0 of the first setting. s1 Make a judgment; if the test reference optical power value P1 is equal to the power setting value P s1 If the result is positive, proceed to the next step; otherwise, control the adjustable optical attenuator to adjust the monochromatic light power value by an attenuation value α until the test reference light power value P1 finally equals the power setting value P. s1 ;
[0050] Step S3: Switch the 1×2 optical switch to the second channel. The calibration light enters the spectrometer's beam splitter module through the second channel of the 1×2 optical switch. The beam splitter module starts scanning. After the calibration light enters the beam splitter module through the second channel of the 1×2 optical switch, it is incident on the detector surface. The detector performs photoelectric conversion, converting the optical signal into an analog electrical signal. The analog electrical signal is then acquired by the data acquisition module and converted into a digital electrical signal. The analog electrical signal is then transmitted to the FPGA to form a spectral curve. Based on the spectral curve, a peak search algorithm is used to locate the peak wavelength position.
[0051] Step S4: Repeat the scan multiple times to obtain the peak value V searched after the j-th (j=1,2,3,…,M) scan. ij The voltage value V at the peak of the i-th gear is obtained by averaging. i It can be expressed by formula (1), that is:
[0052]
[0053] Step S5: After the repeated scan is completed, determine the reference optical power value P of the i-th position. i Is it equal to the minimum power value P? min If not, proceed with steps S2 to S5 above to obtain the voltage value V at the peak value of the i-th gear corresponding to the reference optical power value of the (i+1)-th gear. i+1Where α is the set attenuation value; conversely, the calibration coefficient calculation module obtains the reference optical power value (i.e., calibration power value) and voltage value for each of the N ranges through the power monitoring module, the spectrometer's data acquisition module, and the FPGA, and calculates the power calibration coefficient.
[0054] Specifically, the calibration power values P of N levels are... i With the test voltage value V i (i=1,2,3,…,N), the power calibration coefficients a, b, c, d are calculated by performing cubic polynomial fitting according to the following formula (2) through the calibration coefficient calculation module.
[0055] P = a * V 3 +b*V 2 +c*V+d (2)
[0056] Furthermore, considering the power values at other wavelengths across the entire spectral range, the above formula (2) can be transformed into formula (3), namely:
[0057] P(λ)=a*V(λ) 3 +b*V(λ) 2 +c*V(λ)+d (3)
[0058] Where λ represents wavelength.
[0059] Step S6: After calibration, during actual testing, switch the 1×2 optical switch to the first channel. The light to be tested enters the beam splitting module through the input optical interface and the first channel of the 1×2 optical switch. After diffraction and beam splitting, it passes through the detector. The data acquisition module collects the photoelectric signal to be tested and extracts the power calibration coefficients a, b, c, and d from the calibration coefficient storage module. Then, the calibrated power value of the light to be tested is calculated, reducing the error between the test value and the actual value, thereby improving the linearity of the spectral power.
[0060] Furthermore, a secondary calibration is performed based on the calculated spectral power across the entire wavelength range.
[0061] Specifically, P D (λ0) is the calibrated display output value of the calculated power value P(λ), which can be expressed by formula (4):
[0062] P D (λ)=f(λ)*P(λ) (4)
[0063] Where f(λ) is the normalized responsivity curve based on the power value P(λ0) at λ0. This responsivity curve is the original curve obtained after the spectrometer's factory test, stored in memory, and retrieved during power calibration. The responsivity curve is obtained by testing a standard broadband light source using a standard spectrometer, resulting in the standard spectral curve P. B (λ), and then using the spectrometer of this embodiment to test a standard broadband light source, the obtained spectrum curve P′ is obtained. B If (λ), then the response rate curve is f(λ) = P B (λ) / P′ B (λ).
[0064] Theoretically, f(λ0) = 1; however, wavelength shifts can introduce errors in spectral power calculations, such as... Figure 3 As shown, if λ0′ is taken as λ0, that is, f(λ0′) is taken as f(λ0), then the display power value P at other wavelengths is calculated. D (λ) may contain errors.
[0065] Therefore, in order to eliminate the influence of wavelength deviation, it is necessary to perform secondary calibration on the power value calculated based on the power calibration coefficient and the test voltage value. This requires modifying the above formula (4). In this embodiment, for example... Figure 4 As shown, the original response rate curve is shifted, introducing a wavelength error curve δ(λ). The error curve δ(λ) is obtained from the fitting error during wavelength calibration, and the full-spectrum display power value P is calculated from the power value at the current test wavelength point. D (λ), expressed by formula (5):
[0066] P D (λ)=f[λ+δ(λ)]*P(λ) (5)
[0067] Combining the above formulas (3) and (5), we obtain the final power calculation formula (6):
[0068] P D (λ)=f[λ+δ(λ)]*{a*V(λ) 3 +b*V(λ) 2 +c*V(λ)+d} (6)
[0069] The error curve δ(λ) is obtained from the error after fitting during wavelength calibration. Specifically, the spectrometer is calibrated for wavelength before power calibration using a standard light source. The characteristic spectral wavelength of the standard light source is λ. B After calibration, the measured wavelength is λ, then the error curve is δ(λ)=λ-λ B .
[0070] Next, the data acquisition module of the spectrometer inputs the light to be measured, extracts the calibration coefficients a, b, c, d, as well as the original response rate curve f(λ) and wavelength deviation curve δ(λ) from the calibration coefficient storage module, and combines them with the acquired voltage value V(λ) to calculate the final power value P according to the above formula (6). D (λ). The power value obtained according to formula (6) can reduce the error between the test value and the actual value, thereby improving the linearity of the spectral power; at the same time, the fitting curve itself is continuous and there is no power gap phenomenon, which can ensure the continuity of power. Moreover, this embodiment eliminates the deviation of spectral power caused by wavelength shift through the above scheme, ensuring that the final obtained power value is more accurate.
[0071] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.
[0072] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
[0073] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.
Claims
1. A spectrometer power calibration device, characterized in that, include: DFB laser, tunable optical attenuator, 50:50 beam splitter, 1×2 optical switch, drive circuit, power adjustment module, power monitoring module, calibration coefficient calculation module, and calibration coefficient storage module; The power adjustment module is used to control the driving circuit and the adjustable light attenuator. It drives the DFB laser, which serves as a reference light source, to generate monochromatic light for power calibration by controlling the driving circuit. It adjusts the attenuation value of the monochromatic light generated by the DFB laser by controlling the adjustable light attenuator. The 50:50 beam splitter is used to split the input monochromatic light into two beams: a reference beam and a calibration beam. The reference beam enters the power monitoring module, which is used to obtain the reference power value of the reference beam. The calibration light enters the spectrometer's beam splitting module through the second channel of a 1×2 optical switch. After being split by the beam splitting module, it is incident on the detector for photoelectric conversion. The electrical signal is then acquired by the data acquisition module, and the power value is obtained through the FPGA. The calibration coefficient calculation module calculates the power calibration coefficient based on the reference power value of the reference light and the power value of the calibration light. The calibration coefficient storage module is used to store the power calibration coefficients calculated by the calibration coefficient calculation module, and also stores the original response rate curve and wavelength deviation curve. The calculation of the power calibration coefficient includes: performing a cubic polynomial fit between the calibration power values Pi of N ranges and the test voltage values Vi through the calibration coefficient calculation module to calculate the power calibration coefficient. Secondary calibration is performed based on the calculated spectral power across the entire wavelength range; The secondary calibration comprises introducing an error curve δ(λ) of the wavelength, and calculating the display power value P of the full spectrum segment from the power value of the current test wavelength point D (λ), and the formula is: ； Where f(λ) is the normalized response rate curve based on the power value at λ, a, b, c, and d are power calibration coefficients, V(λ) is the test voltage value at wavelength λ, and the error curve δ(λ) is obtained from the error after fitting during wavelength calibration.
2. The spectrometer power calibration device as described in claim 1, characterized in that, The spectrometer consists of a spectrometer, ...
3. A method for calibrating the power of a spectrometer, applied to a spectrometer power calibration device as described in any one of claims 1-2, characterized in that, Includes the following steps: Step 1: Turn on the drive circuit of the DFB laser, set the initial calibration power value P0 of the initial setting to the maximum power value Pmax through the power adjustment module, and generate monochromatic light of the corresponding power through the DFB laser. Step 2: The adjustable optical attenuator adjusts the input monochromatic light power value according to the set attenuation value. The adjusted monochromatic light is split into two beams, a reference beam and a calibration beam, by a 50:50 beam splitter. The power monitoring module is turned on to monitor the reference light power value and determine whether the reference light power value meets the judgment condition. If it does, proceed to the next step. Step 3: The calibration light enters the spectrometer's spectral dispersive module through the second channel of the 1×2 optical switch. The spectral dispersive module begins scanning. After being dispersed, the calibration light is incident on the detector surface. The data acquisition module and FPGA generate a spectral curve. Based on the spectral curve, a peak search algorithm is used to locate the peak wavelength position, and then the voltage value at the peak is determined. Step 4: After the scan is completed, determine whether the reference optical power value of the current gear is equal to the minimum power value. If not, repeat steps 2 to 4 until the condition is met. If so, the calibration coefficient calculation module obtains the reference optical power value and test voltage value of each gear and calculates the power calibration coefficient.
4. The spectrometer power calibration method as described in claim 3, characterized in that, The determination condition in step 2 is: The power adjustment module makes a judgment based on the test reference light power value Pi and the power setting value Ps of the current gear. If the test reference light power value Pi is equal to the power setting value Ps, the next step is performed. Otherwise, the adjustable light attenuator is controlled to adjust the monochromatic light power value by an attenuation value α until the test reference light power value Pi finally equals the power setting value Ps.
5. The spectrometer power calibration method as described in claim 3, characterized in that, In step 3, the scan is repeated multiple times to obtain the peak value Vij searched after the j-th scan. The voltage value Vi at the peak value of the i-th gear is obtained by averaging, where j=1,2,3,…,M and i=1,2,3,…,N.
6. The spectrometer power calibration method as described in claim 3, characterized in that, In step 4, it is determined whether the reference optical power value Pi of the i-th gear is equal to the minimum power value Pmin. If not, steps 2 to 4 are repeated in a loop. The voltage value Vi+1 at the peak of the i-th gear corresponding to the reference optical power value of the (i+1)-th gear is calculated. Otherwise, the calibration coefficient calculation module obtains the reference optical power value and test voltage value of each gear (i.e., N gears) through the power monitoring module, the data acquisition module of the spectrometer, and the FPGA, and calculates the power calibration coefficient.