CN117848492A - Photodiode laser power detection method and device - Google Patents
Photodiode laser power detection method and device Download PDFInfo
- Publication number
- CN117848492A CN117848492A CN202311863008.6A CN202311863008A CN117848492A CN 117848492 A CN117848492 A CN 117848492A CN 202311863008 A CN202311863008 A CN 202311863008A CN 117848492 A CN117848492 A CN 117848492A
- Authority
- CN
- China
- Prior art keywords
- laser
- power
- photodiode
- calibrated
- characterization
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 238000001514 detection method Methods 0.000 title claims abstract description 56
- 238000005070 sampling Methods 0.000 claims abstract description 120
- 238000012512 characterization method Methods 0.000 claims abstract description 91
- 238000000034 method Methods 0.000 claims abstract description 51
- 230000000737 periodic effect Effects 0.000 claims abstract description 15
- 238000012544 monitoring process Methods 0.000 claims abstract description 13
- 238000004364 calculation method Methods 0.000 claims description 49
- 238000005259 measurement Methods 0.000 claims description 21
- 239000000919 ceramic Substances 0.000 claims description 16
- 238000002474 experimental method Methods 0.000 claims description 16
- 230000003287 optical effect Effects 0.000 claims description 14
- 238000012360 testing method Methods 0.000 claims description 9
- 230000008859 change Effects 0.000 claims description 8
- 230000002159 abnormal effect Effects 0.000 claims description 5
- 230000035484 reaction time Effects 0.000 claims description 5
- 238000012545 processing Methods 0.000 claims description 4
- 230000008878 coupling Effects 0.000 description 10
- 238000010168 coupling process Methods 0.000 description 10
- 238000005859 coupling reaction Methods 0.000 description 10
- 238000010586 diagram Methods 0.000 description 10
- 239000013307 optical fiber Substances 0.000 description 10
- 239000000523 sample Substances 0.000 description 6
- 230000005540 biological transmission Effects 0.000 description 5
- 230000008569 process Effects 0.000 description 5
- 230000009471 action Effects 0.000 description 4
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000000691 measurement method Methods 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 230000002441 reversible effect Effects 0.000 description 3
- 230000005856 abnormality Effects 0.000 description 2
- 230000002238 attenuated effect Effects 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 230000006870 function Effects 0.000 description 2
- 238000009434 installation Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000002834 transmittance Methods 0.000 description 2
- 238000012935 Averaging Methods 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 238000004659 sterilization and disinfection Methods 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Landscapes
- Photometry And Measurement Of Optical Pulse Characteristics (AREA)
Abstract
The invention relates to the field of laser power detection, in particular to a photodiode laser power detection method and device. Applied to a laser system, the method comprises the following steps: controlling a photodiode sampling circuit to perform periodic sampling to obtain characterization data, wherein the characterization data comprise characterization PWM mode laser pulse energy, characterization PWM mode laser pulse peak power and characterization CW mode laser pulse peak power; calculating to obtain laser average power according to the calibrated proportionality coefficient and the characterization data, wherein the calibrated proportionality coefficient is determined by the structure of the laser system, and the laser average power corresponding to the preset power is obtained to realize the detection of the laser power of the laser; and monitoring the output power of the laser system in real time according to the preset power of the laser system and the laser average power difference value.
Description
Technical Field
The invention relates to the field of laser power detection, in particular to a photodiode laser power detection method and device.
Background
The range of the existing laser average power detection instrument is very limited, generally two ranges are very few, three ranges can be switched, and low-power detection and high-power detection cannot be achieved.
At present, a part of optical laser average power detection instruments only can detect specific laser power, and detection of any laser average power cannot be realized.
Therefore, a reliable photodiode laser power detection method and device are lacked, so that the method and device can be widely applied to detection occasions with different laser average powers, and power detection guarantee is provided for more laser devices.
Disclosure of Invention
The invention aims to provide a photodiode laser power detection method and device, which are used for solving the problem that the method and device cannot be widely applied to detection occasions with different laser average powers at present and providing power detection guarantee for more laser devices.
The embodiment of the invention provides a photodiode laser power detection method, which is applied to a laser system and comprises the following steps: controlling a photodiode sampling circuit to perform periodic sampling to obtain first characterization data, wherein the first characterization data comprises characterization PWM mode laser pulse energy, characterization PWM mode laser pulse peak power and characterization CW mode laser pulse peak power; calculating to obtain laser average power according to a calibrated proportionality coefficient and the first characterization data, wherein the calibrated proportionality coefficient is determined by the structure of the laser system; and monitoring the output power of the laser system in real time according to the difference value between the preset power of the laser system and the average power of the laser.
Optionally, the calculating to obtain the average power of the laser according to the calibrated scaling factor and the first characterization data includes: based on PWM mode laser, according to a first calibrated proportionality coefficient, the pulse energy of the characterization PWM mode laser and the pulse frequency of the PWM mode laser, passing through the first laserAn average power calculation formula is used for calculating to obtain the first laser average power; the first laser average power calculation formula is: p (P) 1 ＝S pd1 ×K 1 ×f 1 The method comprises the steps of carrying out a first treatment on the surface of the Wherein P is 1 For the first laser average power, K 1 For the first calibrated scale factor, S pd1 To characterize the PWM mode laser pulse energy, f 1 Pulse frequency for the PWM mode laser;
calculating to obtain a second laser average power through a second laser average power calculation formula according to a second calibrated proportionality coefficient and the laser pulse peak power representing the PWM mode; the second laser average power calculation formula is: p (P) 2 ＝P 1 ′×K 2 The method comprises the steps of carrying out a first treatment on the surface of the Wherein P is 2 For the second laser average power, P 1 ' is the peak power, K of the laser pulse of the characterization PWM mode 2 And (5) the second calibrated scaling factor.
Optionally, the calculating to obtain the average power of the laser according to the calibrated scaling factor and the first characterization data further includes: calculating to obtain third laser average power according to a third calibrated proportionality coefficient and the peak power of the laser pulse representing the CW mode based on the CW mode laser through a third laser average power calculation formula; the third laser average power calculation formula is: p (P) 3 ＝P 2 ′×K 3 The method comprises the steps of carrying out a first treatment on the surface of the Wherein P is 1 For the third laser average power, P 2 ' is the peak power, K of the laser pulse of the characteristic CW mode 3 And (5) a scaling factor for the third calibration.
Optionally, the method further comprises:
according to the fixed values of resolution, total attenuation rate, main control chip reaction time and ADC chip sampling time, determining that the scaling factor with calibration is a fixed value; and/or determining that the scaling factor with the calibration is a fixed value according to the fixed values of the resolution and the total attenuation rate; the resolution is the incident light peak power of the photodiode corresponding to the unit voltage value of the photodiode sampling circuit, and the total attenuation rate is the ratio between the peak power value of laser before passing through the spectroscope and the incident light peak power of the photodiode;
controlling the photodiode sampling circuit to acquire second characterization data, wherein the second characterization data comprises characterization PWM mode laser experiment pulse energy, characterization PWM mode laser experiment pulse peak power and characterization CW mode laser experiment pulse peak power;
and obtaining the calibrated proportionality coefficient according to the ratio of the measured power of the laser system to the second characterization data, wherein the measured laser power of the laser system is measured by a thermopile type laser power meter.
Optionally, the obtaining the calibrated scaling factor according to the ratio of the measured power of the laser system to the second characterization data includes: based on PWM mode laser, obtaining a first calibrated proportionality coefficient according to a first laser actual measurement power, the characterization PWM mode experimental laser pulse energy and the PWM mode laser experimental pulse frequency by a first calibrated proportionality coefficient calculation formula; the first calibrated scaling factor calculation formula is:wherein K is 1 For a first calibrated scale factor, P 4 For the first laser measured power, S pd2 Experimental laser pulse energy, f, for the characterization of PWM mode 2 Experimental pulse frequency for the PWM mode laser;
obtaining a second calibrated proportional coefficient according to the second laser actual measurement power and the pulse peak power of the laser experiment of the characterization PWM mode through a second calibrated proportional coefficient calculation formula; the calculation formula of the scaling factor of the second calibration is as follows:wherein K is 2 For the second calibrated scale factor, P 5 For the second laser measured power, P 3 ' is the peak power of the laser experimental pulse of the characterization PWM mode.
Optionally, the laser system is based on the fact that the laser system is used for the laser Measuring the ratio of the power to the second characterization data to obtain the calibrated scaling factor, and further comprising: based on the CW mode laser, obtaining a third calibrated proportionality coefficient according to the third laser actual measurement power and the peak power of the laser experimental pulse of the characteristic CW mode through a third calibrated proportionality coefficient calculation formula; the calculation formula of the scaling factor of the third calibration is as follows:wherein K is 3 For the third calibrated scale factor, P 6 For the third laser measured power, P 4 ' is the peak power of the laser experimental pulse characterizing the CW mode.
Optionally, the method further comprises: and re-determining the calibrated scale factor by changing the resolution and/or the total attenuation rate, wherein the re-determining of the calibrated scale factor realizes the range change of the laser power detected by the photodiode.
Optionally, the monitoring the output power of the laser system in real time according to the difference between the preset power of the laser system and the average power of the laser includes: calculating the absolute value of the difference value between the average laser power and the preset power; if the absolute value exceeds the preset value, the laser system is abnormal, and alarm processing is carried out.
Compared with the prior art, the photodiode laser power detection method provided by the invention has the beneficial effects that:
according to the photodiode laser power detection method provided by the embodiment of the invention, the photodiode sampling circuit is controlled to perform periodic sampling to obtain first characterization data, wherein the first characterization data comprise characterization PWM mode laser pulse energy, characterization PWM mode laser pulse peak power and characterization CW mode laser pulse peak power, so that the acquisition of laser information data is realized; calculating to obtain the average power of the laser according to the calibrated proportionality coefficient and the first characterization data, wherein the calibrated proportionality coefficient is determined by the structure of the laser system, and the average power corresponding to the preset power is obtained, so that the detection of any laser power of the laser is realized; and monitoring the output power of the laser system in real time according to the preset power of the laser system and the laser average power difference value so as to realize the detection occasion widely applied to different laser average powers and provide power detection guarantee for more laser devices.
The embodiment of the invention also provides a device for detecting the laser power of the photodiode, which is applied to the laser system and is used for the method for detecting the laser power of the photodiode, and the device comprises the following steps: spectroscope: for splitting the laser of the laser system into two beams; the first laser beam is transmitted to the rear light path module, and the second laser beam is used for detecting the laser power of the photodiode; ceramic sheet: the second laser beam is used for being changed into diffuse light to be transmitted to the photodiode, and the total attenuation rate of the photodiode sampling circuit to the second laser beam can be changed; photodiode sampling circuit: for converting the incident diffuse light peak power of the photodiode into a voltage value signal; and the control module is used for: the sampling circuit is used for controlling the photodiode sampling circuit to perform periodic sampling to obtain a sampling measured value, wherein the sampling measured value is a voltage value; the calculation module: for calculating an average power of the laser light from the sampled measurements.
Optionally, the photodiode sampling circuit includes: a photodiode for converting an optical signal into an electrical signal; the control module includes: the main control chip is used for sending out a periodic sampling control instruction, and the ADC chip is used for converting the voltage value signal of the photodiode sampling circuit into a digital signal.
The photodiode laser power detection device provided by the invention has the beneficial effects that: the same technical effects as those of the above-mentioned photodiode laser power detection method can be achieved, and in order to avoid repetition, the description is omitted here.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view of a photodiode according to an embodiment of the present invention;
FIG. 2 is a schematic view of a diffuse reflection light path according to an embodiment of the present invention;
FIG. 3 is a schematic view of a transmission path in an embodiment of the present invention;
FIG. 4 is a schematic diagram of a laser mode according to an embodiment of the present invention;
FIG. 5 is a schematic flow chart of a method for detecting laser power of a photodiode according to an embodiment of the present invention;
FIG. 6 is a schematic diagram showing the relationship between the response time of the controller and the sampling time of the ADC chip according to the embodiment of the present invention;
FIG. 7 is a schematic diagram of sampling according to an embodiment of the present invention;
FIG. 8 is a schematic diagram of a laser power detection device of a photodiode according to an embodiment of the present invention;
description of the drawings:
1-a laser light source; 2-a medical optical fiber; 3-optical fiber quick connector; 4-a collimating lens;
5-spectroscope; 6-a rear light path; 7-a photodiode;
8-metal sheets; 9-a first ceramic sheet; 10-a second ceramic sheet;
a-PWM mode laser; B-CW mode laser;
51-a main control chip; 52-ADC chip; 53-laser.
Detailed Description
In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings.
Currently, there are three methods for measuring laser power/energy: the first is a direct measurement method adopting a light-heat conversion mode for signal acquisition, wherein a laser power probe/energy probe of the method is an absorber coated with thermoelectric materials, the thermoelectric materials absorb laser energy and convert the laser energy into heat, so that the temperature change of the probe generates current, and the current is converted into a voltage signal through a sheet annular resistor and is transmitted; the second is an indirect measurement method adopting a photoelectric conversion mode for signal acquisition, wherein a photoelectric probe is selected to convert a laser signal into a current signal, and then the current signal is converted into a voltage signal in direct proportion to the input laser power/energy, so that the energy measurement is completed; the third is an indirect measurement method adopting a light-pressure conversion mode for signal acquisition, the method obtains a light pressure value generated by laser through calculating by detecting the micro-displacement generated by the laser striking the mirror surface of the balance, and finally obtains the average power of the incident laser through calculation.
The first method can be expressed as a method of adopting thermal stacking, forming heat by irradiating laser to a detection surface of the power meter, and then converting the heat into an analog electric signal again, thereby obtaining the power meter by sampling and calculating. The time period of the detection needs to be relatively long, typically on the order of seconds or more. In the third mode, the required light path and structure are very precise, and the requirements on temperature, humidity and vibration of the working environment are relatively high. The invention uses optics of the second method: the photodiode is combined with an integral accumulation summation algorithm, and in a pulse laser mode, only one pulse time is needed to be accumulated, so that the specific average power can be calculated, the time from the receiving of laser to the identification of the average power is very much faster than that of the first method, and whether the power is abnormal or not can be obtained through feedback calculation in time, so that damage is reduced in time; because the light path structure is relatively simple and small, the requirements on the use environment are greatly reduced compared with the third scheme. Especially, the laser light source is very suitable for laser medical appliance products.
Referring to the schematic structural diagram of the photodiode shown in fig. 1, the photodiode is an element capable of converting an optical signal into an electrical signal, when light irradiates on a photosurface of the photodiode and enters an intrinsic layer, photons carrying energy enter a PN junction, energy is transferred to bound electrons on covalent bonds, and the bound electrons break loose the covalent bonds after energy of the bound electrons increases to a certain degree, so that photo-generated carriers are formed, and electron hole pairs are generated. The carrier drifts under the action of the reverse voltage, so that the reverse current increases rapidly, and the increasing degree is proportional to the light intensity. By utilizing the characteristic of the photodiode, the real-time monitoring of the laser light intensity change can be realized by collecting, processing and monitoring the reverse current generated after the photodiode is irradiated by the incident light with different light intensities. According to the embodiment of the invention, the real-time monitoring display and the power deviation judgment of the laser power are realized by combining the light intensity change detected by the photodiode with the light path attenuation condition and the setting parameters of the laser light source.
Referring to the diffuse reflection optical path schematic diagram shown in fig. 2 and the transmission optical path schematic diagram shown in fig. 3, in a part of active medical devices, the medical optical fiber 2 is required to be used as a transmission medium of laser energy, so that the laser energy generated by the laser source 1 is transmitted to a focus position. Because of the special use environment and application scene of the active medical apparatus, the medical optical fiber 2 needs to be replaced frequently, or the medical optical fiber 2 needs to be detached from the medical apparatus body frequently for disinfection, so that the active medical apparatus is required to realize the rapid detachment and installation of the medical optical fiber 2, namely, the rapid detachment and connection of the medical optical fiber 2 and the coupling module. Based on the above characteristics, the laser output mode of the active medical device at the distal end of the medical optical fiber 2 adopts a coupling output mode. The coupling module is used for collimating and refocusing the laser output by the laser source 1, and is the last device before the laser energy enters the rear light path 6, so that any position or component before the space coupler is failed can cause the laser power to change, and the laser power change can be detected and fed back at the coupling module. Thus determining that the coupling module is a better laser power detection position. In the embodiment of the invention, the photodiode 7 is arranged on the coupling module to monitor the laser output power, and the alarm is given when the laser output power is abnormal. As shown in fig. 2, the coupling module includes: the optical fiber rapid connector 3, the collimating lens 4, the spectroscope 5, the rear light path 6, the photodiode 7, the metal sheet 8 and the first ceramic sheet 9, wherein the metal sheet 8 can be replaced by the ceramic sheet; as shown in fig. 3, the coupling module includes: the optical fiber rapid connector 3, the collimating lens 4, the spectroscope 5, the rear optical path 6, the photodiode 7 and the second ceramic wafer 10. The beam splitter 5 in the coupling module splits the collimated light into a small part, the small part is incident on the laser receiving surface of the photodiode, the photodiode 7 feeds back the characteristics of the incident light beam, and then the voltage value corresponding to the incident light peak power of the photodiode is obtained through the photodiode sampling circuit.
Referring to fig. 3, it is verified through experiments that, in combination with the testing effect and the difficulty of installation and debugging, preferably, an optical path as shown in fig. 3 is used, wherein the collimated probe beam split by the beam splitter 5 of the coupling module is transmitted by a second ceramic plate 10 with a transmittance of about 17% to form scattered light with disordered directions, and the photodiode 7 is located behind the second ceramic plate 10 to sample the received laser. With continued reference to fig. 3, the ratio of the beam splitter 5 and the transmittance of the second ceramic plate 10 in the coupler are fixed, and when the positional relationship between the photodiode 7 and the second ceramic plate 10 is determined, the proportion of the transmitted light that can be received by the light sensing surface of the photodiode 7 and that of the transmitted light that passes through the second ceramic plate 10 is also a relatively determined value. The relative position distance between the photodiode 7 and the second ceramic plate 10, the split ratio of the beam splitter 5, the attenuation ratio of the second ceramic plate 10, and the like are all used to attenuate the light intensity of the laser light irradiated to the detection surface of the photodiode 7. In laser beam transmission, the attenuation is directly reflected on the attenuation of pulse peak power, and L is used 1 Representing the coefficient between the peak power of the collimated beam before passing through the beam splitter 5 and the peak power of the incident light of the photodiode 7, representing the total attenuation rate, i.e. L 1 Is a fixed value. The formula can be obtained:
P P ＝P P1 ×L 1 ，
wherein P is P Peak power of incident light, P, for photodiode 7 P1 Is the peak power of the laser before passing through the beam splitter 5. Resolution D in photodiode sampling circuit P The resolution of the photodiode sampling circuit to the laser power, namely the incident light peak power of the photodiode 7 corresponding to the unit voltage value; due to resolution D P Is determined by the resistance value of the sampling resistor in the photodiode sampling circuit and inversely proportional to the resistance value of the sampling resistor, thus whenD when the resistance value of the sampling resistor is determined P Is also a constant value. The relation among the voltage value of the photodiode sampling circuit, the power resolution in the photodiode sampling circuit and the incident light peak power of the photodiode 7 satisfies the unitary first-order equation:
P P ＝PD×D p +b，
wherein PD is the voltage value of the photodiode sampling circuit, D P For power resolution, P in photodiode sampling circuit P The incident light peak power of the photodiode 7, b is the constant background noise of the photodiode 7; since the sampling noise of the ADC chip caused by the dark current in the photodiode 7 can be adjusted to be very small by adjusting the sampling circuit, it can be ignored, and the constant noise b value of the sampling value of the photodiode can be approximately obtained by removing:
P P ＝PD×D p 。
Referring to the laser mode schematic diagram shown in fig. 4, comprising: a pulse width modulation (PWM, pulse Width Modulation) mode laser a and a Continuous Wave (CW) mode laser B.
An embodiment of the present invention provides a method for detecting laser power of a photodiode, referring to a schematic flowchart of the method for detecting laser power of a photodiode shown in fig. 5, and the method is applied to a laser system, and includes:
s510, controlling a photodiode sampling circuit to perform periodic sampling to acquire first characterization data.
Wherein, the first characterization data includes characterization PWM mode laser pulse energy, characterization PWM mode laser pulse peak power, and characterization CW mode laser pulse peak power.
S520, calculating to obtain the laser average power according to the calibrated proportionality coefficient and the first characterization data.
Wherein the scaled scaling factor is determined by the configuration of the laser system.
And S530, monitoring the output power of the laser system in real time according to the difference value between the preset power of the laser system and the average power of the laser.
The preset power of the laser system is the set power when the laser works, the average laser power is the actual output power of the laser system, and the condition of the output power of the laser is monitored in real time according to the difference value between the preset power of the laser system and the average laser power.
Optionally, the monitoring the output power of the laser system in real time according to the preset power value of the laser system and the laser average power difference value includes: calculating the absolute value of the difference between the average laser power and the preset power; if the absolute value exceeds the preset value, the laser system is abnormal, and alarm processing is carried out.
According to the photodiode laser power detection method provided by the embodiment of the invention, the photodiode sampling circuit is controlled to perform periodic sampling to obtain first characterization data, wherein the first characterization data comprise characterization PWM mode laser pulse energy, characterization PWM mode laser pulse peak power and characterization CW mode laser pulse peak power, so that the acquisition of laser information data is realized; calculating to obtain the average power of the laser according to the calibrated proportionality coefficient and the first characterization data, wherein the calibrated proportionality coefficient is determined by the structure of the laser system, and the average power corresponding to the preset power is obtained, so that the detection of any laser power of the laser is realized; and monitoring the output power of the laser system in real time according to the preset power of the laser system and the laser average power difference value so as to realize the detection occasion widely applied to different laser average powers and provide power detection guarantee for more laser devices.
In the embodiment of the present invention, step S520 is as follows.
Optionally, the calculating to obtain the laser average power according to the calibrated scaling factor and the first characterization data includes: based on PWM mode laser, calculating to obtain a first laser average power through a first laser average power calculation formula according to a first calibrated proportionality coefficient, the characterization PWM mode laser pulse energy and the PWM mode laser pulse frequency;
the first laser average power calculation formula is as follows:
P 1 ＝S pd1 ×K 1 ×f 1 ；
wherein P is 1 For the first laser average power, K 1 For the first calibrated scale factor, S pd1 To characterize the PWM mode laser pulse energy, f 1 The pulse frequency of the PWM-mode laser is the pulse frequency.
Optionally, the calculating to obtain the laser average power according to the calibrated scaling factor and the first characterization data further includes: based on the PWM mode laser, calculating to obtain a second laser average power according to a second calibrated proportionality coefficient and the peak power of the laser pulse representing the PWM mode by a second laser average power calculation formula;
the calculation formula of the second laser average power is as follows:
P 2 ＝P 1 ′×K 2 ；
wherein P is 2 For the second laser average power, P 1 ' is the characterization of the peak power, K, of the PWM mode laser pulse 2 And the second calibrated scaling factor.
Optionally, the calculating to obtain the laser average power according to the calibrated scaling factor and the first characterization data further includes: calculating to obtain a third laser average power according to a third calibrated proportionality coefficient and the peak power of the laser pulse representing the CW mode based on the CW mode laser and a third laser average power calculation formula;
the calculation formula of the third laser average power is as follows:
P 3 ＝P 2 ′×K 3 ；
wherein P is 1 For the third laser average power, P 2 ' to characterize the peak power, K, of the CW mode laser pulse 3 And the third calibrated proportionality coefficient is obtained.
According to the embodiment of the invention, the laser power output by any preset power value of the laser can be detected through the calculation formula of the laser average power according to the calibrated proportionality coefficient and the first characterization data.
The method for detecting the laser power of the photodiode also comprises a calibrated coefficient determination method, and the method has the following implementation mode.
Optionally, the above method for detecting laser power of a photodiode further includes: according to the fixed values of resolution, total attenuation rate, main control chip reaction time and ADC chip sampling time, determining the proportionality coefficient with the calibration as a fixed value; or determining that the scaling factor with the calibration is a fixed value according to the fixed values of the resolution and the total attenuation rate. The resolution is the incident light peak power of the photodiode corresponding to the unit voltage value of the photodiode sampling circuit, namely the peak power value of the laser corresponding to the unit voltage value of the photodiode sampling circuit after attenuation, the total attenuation rate is the ratio between the peak power value of the laser before passing through the spectroscope and the incident light peak power of the photodiode, and the peak power value of the laser before passing through the spectroscope is the unattenuated power value of the laser power.
Controlling the photodiode sampling circuit to acquire second characterization data, wherein the second characterization data comprises characterization PWM mode laser experiment pulse energy, characterization PWM mode laser experiment pulse peak power and characterization CW mode laser experiment pulse peak power;
and obtaining the calibrated proportionality coefficient according to the ratio of the measured power of the laser system to the second characterization data, wherein the measured laser power of the laser system is measured by a thermopile type laser power meter.
Alternatively, the process may be carried out in a single-stage,
and obtaining the calibrated proportionality coefficient according to the ratio of the actually measured power of the laser system to the characterization value.
The laser actual measurement power of the laser system is measured by a thermopile type laser power meter.
Optionally, the obtaining the calibrated scaling factor according to the ratio of the measured power of the laser system to the characterization value includes: based on the PWM mode laser, obtaining the third calibrated proportionality coefficient according to the first laser actual measurement power, the second characterization PWM mode laser pulse energy and the second PWM mode laser pulse frequency through a first calibrated proportionality coefficient calculation formula;
the calculation formula of the scaling factor of the first calibration is as follows:
wherein K is 3 For a third calibrated scale factor, P 3 For the first laser measured power S pd2 For the second characterization of PWM mode laser pulse energy, f 2 The second PWM mode laser pulse frequency is the second PWM mode laser pulse frequency.
It should be noted that, referring to the schematic diagram of the transmission of the sampling signal of the controller chip shown in fig. 6; t is t 1 Communication time t when the main control chip 61 starts the ADC chip 62 to start sampling 0 ＝t 2 +t 3 : the ADC chip 62 detects the voltage value PD from the beginning n Signal to calculate voltage value PD n I.e. the sampling time t of the ADC chip 62 0 ，t 4 : is the voltage value PD of the ADC chip 62 n The time of signal transmission to the main control chip 61, so the time t1=t of the predetermined sampling period 1 +t 2 +t 3 +t 4 . The sampling time t of the ADC chip 62 needs to be considered within a preset sampling period 0 Thus the voltage value PD actually sampled n Is t after the start of the read sampling 0 Voltage value PD detected in time n And t 0 Regarding the performance of the ADC chip, the range is generally more than or equal to 0.09ns, the shorter the reaction time of the ADC chip is, the more complex the process is, and the more expensive the cost is, but the more accurate the sampling result is obtained by combining the photodiode power sampling method provided by the embodiment of the invention. Illustratively, the embodiment of the invention comprehensively considers the cost problem, selects an ADC chip with the sampling time of 3.7 mu s, and does not influence the sampling precision requirement. t is t 0 The sampling time is determined by the ADC chip, T1 is the reaction time of the main control chip, and the efficiency performance of the main control chip for reading the ADC chip is determined, so that after the main control chip and the ADC chip are selected, T1 and T 0 Is determined to determine L 2 ＝T1/t 0 ，L 2 Is a constant.
See the sampling schematic diagram shown in FIG. 7, where t 0 The time for converting the analog signal into the digital signal by the ADC chip is the time for reading the digital signal of the ADC chip by the main control chip, namely the preset sampling period. In the time T1, the voltage value sampled by the main control chip is exactly T 0 And the ADC chip samples the digital signal in time. The main control board calculates the area of the read voltage value within T1 time, and then sums the calculated area values each time, namely adds up the calculated area values, so as to approximately obtain the area S of the whole laser pulse t_pd The area S of the laser pulse is calculated in the embodiment of the invention t_pd The difference between the laser pulse area and the actual laser pulse area is very different from the actual laser pulse area by a large magnitude, so that the difference error is negligible, and the laser pulse area S t_pd The expression of (2) is:
wherein T is the period sampling duration, T1 is the preset sampling period, and T 0 For ADC chip sampling time, L 2 The ratio of the preset sampling period to the sampling time of the ADC chip is a constant PD n For the voltage value obtained by sampling the nth photodiode sampling circuit in the t time,is n t in t time 0 The sum of the voltage values obtained by time sampling is marked asSubstitution into formula (1-1) yields:
S t_pd ＝S pd ×t 0 ×L 2 ，
wherein S is pd Is the main control board calculates the voltage value PD output by the ADC chip to the main control chip n And the sum of the pulse energy and the average power of the PWM mode laser is taken as an important parameter to participate in the algorithm of the pulse energy and the average power of the PWM mode laser.
Because of tContaining n in the room 1 (n 1 T/T1) T1, so the energy E of a single laser pulse of the photodiode photosurface T1 Can be divided into n integrals of energy over time t. Because the energy is equal to the incident light peak power of the photodiode times time, the energy equation for a single T1 time is:
E T1_n ＝P T1_n ×T1， (1-2)
wherein E is T1_n P is the energy in a single T1 time T1_n The peak power of the incident light of the photodiode is obtained by multiplying the voltage value by the resolution of the photodiode sampling circuit, wherein the peak power of the incident light of the photodiode is equal to the voltage value:
P T1_n ＝PD n ×D P ， (1-3)
wherein D is P Since the resolution of the photodiode sampling circuit is the same, the n-th energy value E in t time can be obtained by substituting the formula (1-3) into the formula (1-2) T1_n The expression of (2) is:
E T1_n ＝PD n ×D P ×T1， (1-4)
the laser is attenuated and then irradiates on the photodiode, and the energy E irradiated on the photodiode in the time t is combined with the formula (1-4) t Can be expressed as:
and because of T1/T 0 ＝L 2 It can be obtained by combining the formulas (1-5):
and due to D P 、t 0 、L 2 Is a constant value, and is obtained by the formula (1-6):
in addition, the pulse energy formula in the time T1 before laser attenuation is as follows:
E P1_n ＝P PT1_n ×T1， (1-8)
wherein E is P1_n Pulse energy before laser attenuation, P PT1_n Pulse power before laser attenuation.
And due to L 1 The total attenuation rate is the relation formula of the incident light peak power of the photodiode and the pulse peak power before attenuation is known as follows:
P T1_n ＝P PT1_n ×L 1 ， (1-9)
substituting the formula (1-9) into the formula (1-8) can obtain the pulse energy before laser attenuation:
wherein P is PT1_n For the peak power of laser before attenuation, due toIs the integral value of the peak power of each T1 in the T time, which is equivalent to the integral value of the peak power of each moment in the T time, i.e. the energy E irradiated to the photodiode in the T time t Thereby, can obtain:
substituting the formula (1-7) into the formula (1-10) can obtain:
marking the aboveSubstituting into the formula (1-11) to obtain the formula:
the above (1-12) represents the laser pulse energy before being attenuated by the spectroscope and the integral S of the photodiode sampling value in t pd There is a relationship of coefficient K. Because of D P 、t 0 、L 2 L and 1 is determined by a detection tool, so D P 、t 0 、L 2 L and 1 are all constant values, soTo characterize the PWM mode laser pulse energy, mark +.>The K value is also a constant value, and is a calibrated proportionality coefficient; furthermore, based on the above method, S pd The pulse width modulation method is applicable to PWM mode laser waveforms with arbitrary pulse width.
Since the laser average power is equal to the single pulse energy times the frequency, i.e. p=e×f. According to formulas (1-12), K 1 Expression of (2) and S pd The expression of the average power of the laser before attenuation can be obtained as follows:
P＝E P1 ×f＝K 1 ×S pd ×f，
wherein P is the average power of the laser before attenuation, f is the repetition frequency, and K is used as the reference 1 Derives the laser power before attenuation and the integral S of sampling value in t time pd The relation of (2) is:
the above (1-13) is the integral S of the sampling value of the photodiode in the time period of the laser average power, the repetition frequency and the repetition frequency before attenuation pd The coefficient K existing between 1 Relationship.
Optionally, the obtaining the calibrated scaling factor according to the ratio of the measured power of the laser system to the second characterization data further includes: based on the PWM mode laser, obtaining a second calibrated proportionality coefficient according to the second laser actual measurement power and the pulse peak power of the laser experiment representing the PWM mode through a second calibrated proportionality coefficient calculation formula;
The calculation formula of the scaling factor of the second calibration is as follows:
wherein K is 2 For the second calibrated scale factor, P 5 For the second laser measured power, P' 3 Pulse peak power was tested for the above-described characterization PWM mode laser.
Since the PWM mode laser beam is L 1 For the total attenuation rate, T1 is the period sampling duration of the photodiode sampling circuit, and it can be known that the relation formula of the incident light peak power and the pulse power before attenuation of the photodiode in a single T1 time is:
P T1 ＝P PT1 ×L 1 ， (2-1)
wherein P is T1 Peak power of incident light, P, for photodiode PT1 Pulse power before laser attenuation.
In addition, t is the period sampling duration, and the t time comprises n 2 (n 2 T/T1) T1, and the voltage value of the photodiode, the power resolution in the photodiode sampling circuit, and the incident light peak power of the photodiode satisfy the relation of the unitary first-order equation, it can be known that:
P T1 ＝PD n ×D P +b，
wherein PD n D is the voltage value obtained by the nth photodiode sampling circuit in the time T in the time T1 P For the resolution of the photodiode sampling circuit, b is the constant background noise of the photodiode, and the background noise can be approximately obtained after the background noise is removed:
P T1 ＝PD n ×D P ， (2-2)
calculation of all PDs within t time n Average value of (c) may be obtained:
PD in t time n Average value P 1 The product of the resolution of the photodiode sampling circuit represents the average peak power of the incident light of the photodiode over time t, i.e. P 1 ×D P The average peak power of the incident light of the photodiode in time is equal to the incident light peak power of the photodiode at any moment in time T in the embodiment of the present invention, and the incident light peak power of the photodiode in any time T1 in time T can be replaced, so that the formula (2-3) is substituted into (2-2) to obtain:
P T1 ＝P″ 1 ×D P ， (2-4)
from the formula (2-1) and the formula (2-4), it is possible to obtain:
the relation between the optical power before attenuation and the voltage value obtained by periodic sampling of the photodiode sampling circuit can be deduced from the formula (2-5) as follows:
because of D in the formula (2-6) P And L is equal to 1 Is determined by a detection tool, so D P And L is equal to 1 Are all constant values, so P PT1 With P 1 There is a definite ratio between them, so P 1 To characterize the laser pulse power of PWM mode, i.e. to characterize the peak power P 'of the laser pulse of PWM mode' 1 And characterization of PWM mode laser experiment pulse peak power P' 3 . And due to D P And L is equal to 1 Is determined by a detection toolAre all constant values, so the marksThen K is 2 The constant value is a calibrated proportionality coefficient between a voltage value and a laser power value in a PWM mode, and the voltage value is a sampling value of a photodiode sampling circuit; furthermore, deriving, P', based on the above formula 1 The pulse width is longer, the fluctuation error of the peak value of the laser stable waveform section of the PWM mode is within the allowable error range, for example, the pulse width lasts more than 10ms, the fluctuation error of the laser stable peak value of the PWM mode is within +/-5% of the fluctuation error of the average peak value of the laser, and at the moment P' 1 The method is suitable for representing the peak power of the PWM mode laser pulse.
Optionally, the obtaining the calibrated scaling factor according to the ratio of the measured power of the laser system to the characterization value further includes: based on the CW mode laser, obtaining a third calibrated proportionality coefficient according to the third laser actual measurement power and the peak power of the laser experiment pulse of the characteristic CW mode through a third calibrated proportionality coefficient calculation formula;
the calculation formula of the scaling factor of the second calibration is as follows:
wherein K is 3 For the third calibrated scale factor, P 6 For the third laser measured power, P' 4 Pulse peak power was tested for the above-described characterization CW mode laser.
It should be noted that, as shown in fig. 4, the CW mode laser is a pulse with an infinitely long pulse width from the beginning of the laser emission to the end of the laser emission, and the average power is approximately equal to the peak power, so the sampling algorithm for calculating the pulse waveform area to characterize the pulse energy is no longer applicable. Based on CW mode laser, due to L 1 The total attenuation rate is the relation formula of the incident light power and the light power before attenuation of the photodiode is known as follows:
P P ＝P P1 ×L 1 ， (3-1)
wherein P is P Is the incident light power of the photodiode, P P1 For the optical power before attenuation.
In addition, the relation between the voltage value of the photodiode, the power resolution in the sampling circuit and the incident light peak power of the photodiode can be known:
P P ＝PD l ×D P +b，
wherein PD l For the first voltage value obtained by periodic sampling according to the preset time interval, D P The resolution of the photodiode sampling circuit can be approximately obtained by removing the background noise:
P P ＝PD l ×D P ， (3-2)
from the formula (3-1) and the formula (3-2), it is possible to obtain:
the relation between the laser power before attenuation and the voltage value obtained by periodic sampling of the photodiode sampling circuit can be deduced as follows:
because of D in the formula (3-4) P And L is equal to 1 Is determined by the detection tool, so that D is equal to D P And L is equal to 1 Is of a constant value, so P P1 With PD l There is a definite ratio between, thus PD l (l=1, 2 3·· are all characterized CW the peak power of the mode laser pulse, i.e. characterizing peak power P 'of CW mode laser pulses in embodiments of the invention' 2 And characterization of CW mode laser experiment pulse peak power P' 4 . Because of D P And L is equal to 1 The detection tool determines that the detection tools are constant values, so the detection tool marks the marksThen K is 3 The constant value is a scaling factor of calibration between a voltage value and a laser power value in a CW mode, and the voltage value is a sampling value of a photodiode sampling circuit.
Optionally, the above method for detecting laser power of a photodiode further includes: and the calibrated scale factor is redetermined by changing the resolution or the total attenuation rate so as to realize the range change of the laser power detected by the photodiode.
It should be noted that, according to the above calculation formula of the average laser power, the range of the detected laser power can be changed only by changing the calibrated proportionality coefficient, and the coefficient is related to the relative position of the laser attenuation sheet and the device in the optical path, and under the condition of fixing the relative position of the device in the optical path, the embodiment of the invention can realize the purpose of changing the range only by changing different ceramic sheets. The attenuation coefficients of the attenuation sheets of different models to laser are different, and the attenuation coefficients can be obtained through early test statistics.
On the basis of the foregoing embodiments, the embodiments of the present invention provide an example of performing laser power detection in a PWM laser mode based on the foregoing photodiode laser power detection method, which may specifically be performed with reference to the following steps:
step 1: and determining the scaling factor of the calibration of the PWM mode laser through experimental tests.
The pulse energy and the repetition frequency of the PWM mode laser are set, the power is measured by an external thermopile type power meter, the laser pulse energy is represented by the actual measurement of the photodiode sampling circuit, and the calibrated proportionality coefficient is calculated by the first calibrated proportionality coefficient calculation formula.
Specifically, the experimental test results are shown in table 1, and comprise 5 elements: setting pulse energy, setting repetition frequency, measuring power by a power meter, representing laser pulse energy by actual measurement, and calculating to obtain a calibrated proportionality coefficient. Removing the maximum value and minimum value of the scaling factor K, and averaging to obtain a concentrated value 2.2725 ×10 -7 About equal to 2.27×10 -7 . From the above experimental test data, it can be verified that the explanation is indeedHas a proportionality coefficient K reflecting the actual single laser pulse energy and the sampling integral value S of the chip PD pd Relationship between them. The single pulse energy determines S pd The calculated integral area value, therefore, 3 set pulse energies are selected from the above table 1, and the "measured characteristic laser pulse energy S" in the respective parameter tables thereof pd "should be equal. For example, as in the last table above, the monopulse energy e=0.2j, the actual measurement S in the table pd Should be approximately equal to the average value 900628, but because of the measured value of the power meter, there is an error in human eye recognition, S pd There may also be errors in the sampled values, resulting in some error in the calculated coefficient K.
TABLE 1
Step 2: and calculating the average power of the PWM mode laser according to the calibrated proportionality coefficient.
Illustratively, the average power of the PWM-mode laser is calculated by a first laser average power calculation formula in combination with the calibrated scaling factor measured in step 1, after characterizing the laser pulse energy by the photodiode sampling circuit.
Specifically, the measurement results are shown in table 2, and contain 6 elements: setting pulse energy, a calibrated proportion coefficient, setting a repetition frequency, measuring average power by a power meter, representing laser pulse energy, and calculating to obtain average power and error; scaling factor K calibrated using the above experimental data 1 ＝2.27×10 -7 Randomly selecting single pulse energy of 0.2J and 0.6J under different frequencies, and using a photodiode laser power detection system to test and statistically characterize laser pulse energy S pd Values and average power.
It should be noted that, the error value in table 2 is the error between the calculated average power and the measured average power of the external thermopile type power meter, and the error value is smaller than 5%, so that the method for detecting the laser power of the photodiode can replace the method for detecting the laser power of the external thermopile type power meter.
TABLE 2
Step 3: the average power of the PWM mode laser is monitored in real time.
Specifically, the average power of the laser light actually output needs to be within ±20% of the set average power. And (3) calculating the average power of the PWM laser by utilizing the step (2), comparing the average power with the set average power of the laser, and alarming if the average power exceeds +/-20% of the set average power, wherein the set average power is the product of the set pulse energy and the set repetition frequency.
When the method is needed to be described, before the average power of the PWM mode laser is monitored in real time, the actual measurement average power of the power meter can be consistent with the set power through the correction of the internal work ratio of the laser, namely, the calculation of the average power of the laser is consistent with the actual running power of the laser.
On the basis of the foregoing embodiments, the present invention provides an example of performing laser power detection in CW laser mode based on the foregoing photodiode laser power detection method, which may be specifically performed with reference to the following steps:
step 1: and determining the scaling factor of the calibration of the CW mode laser through experimental tests.
Illustratively, after setting the average power of the CW mode laser, the power is measured by an external thermopile type power meter, the laser pulse energy is represented by the measurement by a photodiode sampling circuit, and the calibrated scaling factor is calculated by the second calibrated scaling factor calculation formula. The measurement results are shown in table 3, and include 4 elements: the CW mode sets the average power, the measured average power of the power meter, the scaling factor characterizing the laser power and the calibration.
TABLE 3 Table 3
Step 2: and calculating the average power of the CW mode laser according to the calibrated scaling factor.
The average power of the CW mode laser is calculated by the second laser average power calculation formula by measuring and characterizing the average power of the laser by the photodiode sampling circuit and combining the calibrated scaling factor measured in the step 1. The test results are shown in table 4, and comprise 6 elements: the CW mode is used for setting average power, actually measured average power of a power meter, representing laser power, calibrated proportion coefficient and error, the error value in the table 4 is the error of the calculated average power and the actually measured average power of an external thermopile type power meter, and the error value is smaller than 8% and is corrected, so that the photodiode laser power detection method can replace the external thermopile type power meter to detect laser power.
TABLE 4 Table 4
Step 3: the average power of the CW mode laser is monitored in real time.
The power abnormality warning function is illustratively realized by comparing the calculated fifth column of average power values with the first column of set power values and setting warning constraints. It should be noted here that the premise of using the power abnormality warning function is that the power correction of the laser light source is very accurate, i.e., the deviation of the output power from the set power is small, such as the first column and the second column should be the same as possible.
Specifically, the calculated average power value can be displayed on a screen display interface in real time, and the dynamic monitoring of the output laser power of the active medical equipment can be realized by setting a proper refresh rate. The average power of the laser actually output needs to be within + -20% of the set average power. And (3) calculating the average power of the CW laser by utilizing the step (2), comparing the average power with the set average power of the laser, and alarming if the average power exceeds +/-20% of the set average power.
The embodiment of the invention provides a photodiode laser power detection device, which is applied to a laser system and is used for realizing the photodiode laser power detection method, and the device comprises the following steps: beam splitter 802: the laser system is used for dividing laser into two beams; the first laser beam is transmitted to the rear light path module, and the second laser beam is used for detecting the laser power of the photodiode; ceramic wafer 804: the second laser beam is converted into diffuse light to be transmitted to the photodiode, and the total attenuation rate of the photodiode sampling circuit to the second laser beam can be changed; photodiode sampling circuit 806: for converting the incident diffuse light peak power of the photodiode into a voltage value signal; control module 808: the sampling circuit is used for controlling the photodiode sampling circuit to perform periodic sampling to obtain a sampling measured value, wherein the sampling measured value is a voltage value; the calculation module 810: for calculating the average power of the laser light based on the sampled measurements.
Optionally, the photodiode sampling circuit 806 includes: a photodiode 8062, wherein the photodiode 8062 is used for converting an optical signal into an electrical signal;
the control module 808 includes: the main control chip 8082 and the ADC chip 8084, wherein the main control chip 8082 is used for sending out a periodic sampling control instruction, and the ADC chip 8084 is used for converting the voltage value signal of the photodiode sampling circuit into a digital signal.
Of course, it will be appreciated by those skilled in the art that implementing all or part of the above-described methods in the embodiments may be implemented by a computer level to instruct a control device, where the program may be stored in a computer readable storage medium, and the program may include the above-described methods in the embodiments when executed, where the storage medium may be a memory, a magnetic disk, an optical disk, or the like.
Finally, it is further noted that relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises the element.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other.
Although the present invention is disclosed above, the present invention is not limited thereto. Various changes and modifications may be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be assessed accordingly to that of the appended claims.
Claims (10)
1. A method of photodiode laser power detection, for use in a laser system, the method comprising:
controlling a photodiode sampling circuit to perform periodic sampling to obtain first characterization data, wherein the first characterization data comprises characterization PWM mode laser pulse energy, characterization PWM mode laser pulse peak power and characterization CW mode laser pulse peak power;
calculating to obtain laser average power according to a calibrated proportionality coefficient and the first characterization data, wherein the calibrated proportionality coefficient is determined by the structure of the laser system;
and monitoring the output power of the laser system in real time according to the difference value between the preset power of the laser system and the average power of the laser.
2. The method of claim 1, wherein calculating the laser average power according to the calibrated scaling factor and the first characterization data comprises:
based on PWM mode laser, calculating to obtain first laser average power through a first laser average power calculation formula according to a first calibrated proportionality coefficient, the characterization PWM mode laser pulse energy and the PWM mode laser pulse frequency;
the first laser average power calculation formula is:
P 1 ＝S pd1 ×K 1 ×f 1 ；
wherein P is 1 For the first laser average power, K 1 For the first calibrated scale factor, S pd1 To characterize the PWM mode laser pulse energy, f 1 Pulse frequency for the PWM mode laser;
calculating to obtain a second laser average power through a second laser average power calculation formula according to a second calibrated proportionality coefficient and the laser pulse peak power representing the PWM mode;
the second laser average power calculation formula is:
P 2 ＝P 1 ′ ×K 2 ；
wherein P is 2 For the second laser average power, P 1 ′ For the characterization of the peak power, K, of the PWM mode laser pulses 2 And (5) the second calibrated scaling factor.
3. The method of claim 1, wherein the calculating the laser average power according to the calibrated scaling factor and the first characterization data, further comprises:
Calculating to obtain third laser average power according to a third calibrated proportionality coefficient and the peak power of the laser pulse representing the CW mode based on the CW mode laser through a third laser average power calculation formula;
the third laser average power calculation formula is:
P 3 ＝P 2 ′ ×K 3 ；
wherein P is 1 For the third laser average power, P 2 ′ For the characterization of CW mode laser pulse peak power, K 3 And (5) a scaling factor for the third calibration.
4. The photodiode laser power detection method of claim 1, wherein the method further comprises:
according to the fixed values of resolution, total attenuation rate, main control chip reaction time and ADC chip sampling time, determining that the scaling factor with calibration is a fixed value; and/or determining that the scaling factor with the calibration is a fixed value according to the fixed values of the resolution and the total attenuation rate; the resolution is the incident light peak power of the photodiode corresponding to the unit voltage value of the photodiode sampling circuit, and the total attenuation rate is the ratio between the peak power value of laser before passing through the spectroscope and the incident light peak power of the photodiode;
controlling the photodiode sampling circuit to acquire second characterization data, wherein the second characterization data comprises characterization PWM mode laser experiment pulse energy, characterization PWM mode laser experiment pulse peak power and characterization CW mode laser experiment pulse peak power;
And obtaining the calibrated proportionality coefficient according to the ratio of the measured power of the laser system to the second characterization data, wherein the measured laser power of the laser system is measured by a thermopile type laser power meter.
5. The method of claim 2 or 4, wherein the obtaining the scaled scaling factor based on a ratio of the measured power of the laser system to the second characterization data comprises:
based on PWM mode laser, obtaining a first calibrated proportionality coefficient according to a first laser actual measurement power, the characterization PWM mode experimental laser pulse energy and the PWM mode laser experimental pulse frequency by a first calibrated proportionality coefficient calculation formula;
the first calibrated scaling factor calculation formula is:wherein K is 1 For a first calibrated scale factor, P 4 For the first laser measured power, S pd2 Experimental laser pulse energy, f, for the characterization of PWM mode 2 Experimental pulse frequency for the PWM mode laser;
obtaining a second calibrated proportional coefficient according to the second laser actual measurement power and the pulse peak power of the laser experiment of the characterization PWM mode through a second calibrated proportional coefficient calculation formula;
The calculation formula of the scaling factor of the second calibration is as follows:
wherein K is 2 For the second calibrated scale factor, P 5 For the second laser measured power, P 3 ′ And (5) testing pulse peak power for the laser in the characterization PWM mode.
6. The method of claim 3 or 4, wherein the obtaining the scaled scaling factor according to a ratio of the measured power of the laser system to the second characterization data further comprises:
based on the CW mode laser, obtaining a third calibrated proportionality coefficient according to the third laser actual measurement power and the peak power of the laser experimental pulse of the characteristic CW mode through a third calibrated proportionality coefficient calculation formula;
the calculation formula of the scaling factor of the third calibration is as follows:
wherein K is 3 For the third calibrated scale factor, P 6 For the third laser measured power, P 4 ′ Pulse peak power was tested for the characterized CW mode laser.
7. The photodiode laser power detection method of claim 1, wherein the method further comprises:
and re-determining the calibrated scale factor by changing the resolution and/or the total attenuation rate, wherein the re-determining of the calibrated scale factor realizes the range change of the laser power detected by the photodiode.
8. The method of claim 1, wherein the monitoring the output power of the laser system in real time according to the difference between the preset power of the laser system and the average power of the laser comprises:
calculating the absolute value of the difference value between the average laser power and the preset power; if the absolute value exceeds the preset value, the laser system is abnormal, and alarm processing is carried out.
9. A photodiode laser power detection device, applied to the laser system, for implementing the power detection method of any one of claims 1 to 8, the device comprising:
spectroscope: for splitting the laser of the laser system into two beams; the first laser beam is transmitted to the rear light path module, and the second laser beam is used for detecting the laser power of the photodiode;
ceramic sheet: the second laser beam is used for being changed into diffuse light to be transmitted to the photodiode, and the total attenuation rate of the photodiode sampling circuit to the second laser beam can be changed;
photodiode sampling circuit: for converting the incident diffuse light peak power of the photodiode into a voltage value signal;
And the control module is used for: the sampling circuit is used for controlling the photodiode sampling circuit to perform periodic sampling to obtain a sampling measured value, wherein the sampling measured value is a voltage value;
the calculation module: for calculating an average power of the laser light from the sampled measurements.
10. The photodiode laser power detection apparatus of claim 9, wherein the photodiode sampling circuit comprises: a photodiode for converting an optical signal into an electrical signal;
the control module includes: the main control chip is used for sending out a periodic sampling control instruction, and the ADC chip is used for converting the voltage value signal of the photodiode sampling circuit into a digital signal.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311863008.6A CN117848492A (en) | 2023-12-29 | 2023-12-29 | Photodiode laser power detection method and device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311863008.6A CN117848492A (en) | 2023-12-29 | 2023-12-29 | Photodiode laser power detection method and device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117848492A true CN117848492A (en) | 2024-04-09 |
Family
ID=90528391
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311863008.6A Pending CN117848492A (en) | 2023-12-29 | 2023-12-29 | Photodiode laser power detection method and device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117848492A (en) |
-
2023
- 2023-12-29 CN CN202311863008.6A patent/CN117848492A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| JP2008002815A (en) | Wavelength variable pulse light generator, and optical tomographic measuring instrument using the same | |
| CN101267766A (en) | Apparatus, system and method of controlling and monitoring the energy of a laser | |
| CN105387933A (en) | Broadband Brewster window adjusting device and method | |
| CN109738064B (en) | Pulse power measuring method of pulse laser | |
| TW201944055A (en) | Carrier lifespan measurement method and carrier lifespan measurement device | |
| JP2006343325A (en) | Device and method for measuring thermophysical property | |
| JP2017067613A (en) | Inspection device and inspection method | |
| CN117848492A (en) | Photodiode laser power detection method and device | |
| KR102038862B1 (en) | Quantum effciency measuring instrument and method for photovoltaic detectors on individual laser pulses | |
| EP3206226B1 (en) | Analysis system and analysis method | |
| TWI479119B (en) | Optical measuring device and optical measuring method | |
| CN117705273A (en) | Photodiode detection laser power sampling method and system | |
| JP7331732B2 (en) | How to evaluate avalanche photodiodes | |
| WO2021059825A1 (en) | Laser processing monitoring method, and laser processing monitoring device | |
| CN108267799A (en) | A kind of high-precision infrared detector time constant tests system and method | |
| US11175249B2 (en) | Physical property value measurement device, physical property value measurement method, and recording medium | |
| JP5608722B2 (en) | Inspection device and method for adjusting inspection device | |
| JP2019145552A (en) | Concentration measuring method and concentration measuring apparatus | |
| KR101579558B1 (en) | Apparatus for sensing laser | |
| JPH06294777A (en) | Measuring method for ultrasonic vibration | |
| CN114812850B (en) | Ultrafast temperature measuring device and method for opaque object based on femtosecond laser | |
| Phethaw et al. | Determination of laser power linearity of thermopile monitor detector used in CO 2 laser calibration system | |
| JP2011209295A (en) | Apparatus and method for measuring thermophysical property | |
| JPH06201488A (en) | Temperature distribution detector | |
| JP2525980B2 (en) | Optical fiber type temperature distribution measuring device |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |