Photoelectric detection circuit and laser

Abstract

The utility model discloses a photoelectric detection circuit and a laser. The photoelectric detection circuit comprises a current detection circuit, an optical path detection circuit and a controller. The current detection circuit is respectively connected with a photoelectric detection probe in the laser and the controller, and the light path detection circuit is connected with the photoelectric detection probe and the controller; the current detection circuit is used for detecting the detection current of the photoelectric detection probe, comparing the detection current with a threshold current and transmitting a current comparison result to the controller; and the light path detection circuit is used for collecting the output voltage detected by the photoelectric detection probe, comparing the output voltage with a threshold voltage and transmitting a voltage comparison result to the controller. According to the photoelectric detection circuit provided by the utility model, an optical signal is converted into a voltage signal through the photoelectric detection probe, the voltage detected by the optical path detection circuit is compared with a threshold voltage, the current detected by the current detection circuit is compared with a threshold current, and the controller judges the state of an optical path according to the comparison result.

Description

Technical Field

[0001] The utility model relates to the technical field of optical detection, and particularly relates to a photoelectric detection circuit and a laser. Background Art

[0002] At present, the internal optical path of a picosecond laser is a pure optical scheme, that is, there is no optical path detection. Since the optical system of the laser is a light-emitting diode (Laser Diode, LD) pump source (seed source) + xenon lamp amplification structure, during the light output process, the light intensities at each level are different. Among them, the seed light is the weakest, and the light energy after being amplified by the xenon lamp is the strongest. However, when the entire system is running, each path of light lacks a photoelectric signal detection device, so that during the test process, the optical signals at each node cannot be collected in real time, and thus the state of the optical path cannot be monitored. Summary of the Utility Model

[0003] The main object of the utility model is to propose a photoelectric detection circuit and a laser, aiming to solve the problem that the optical signals at each node cannot be collected in real time, and thus the state of the optical path cannot be monitored.

[0004] To achieve the above object, the photoelectric detection circuit proposed by the utility model includes: a current detection circuit, an optical path detection circuit, and a controller;

[0005] The current detection circuit is respectively connected to a photoelectric detection probe in the laser and the controller, and the optical path detection circuit is respectively connected to the photoelectric detection probe and the controller;

[0006] The current detection circuit is used to detect the detection current of the photoelectric detection probe, compare the detection current with a threshold current, and transmit the current comparison result to the controller;

[0007] The optical path detection circuit is used to collect the output voltage detected by the photoelectric detection probe, compare the output voltage with a threshold voltage, and transmit the voltage comparison result to the controller;

[0008] The controller is used to determine the output state of the laser according to the current comparison result and the voltage comparison result.

[0009] In an embodiment, the optical path detection circuit includes: an upper limit detection circuit and a lower limit detection circuit. Among them, the photoelectric detection probe includes a first photoelectric detection probe and a second photoelectric detection probe. The first photoelectric detection probe is located on the optical path where the light has undergone amplification processing, and the second photoelectric detection probe is located on the optical path where the light has not undergone amplification processing;

[0010] The upper limit detection circuit is respectively connected to the controller and the first photoelectric detection probe, and the lower limit detection circuit is respectively connected to the controller and the second photoelectric detection probe;

[0011] The upper limit detection circuit is configured to collect the upper limit output voltage of the first photoelectric detection probe, compare the upper limit output voltage with the upper limit threshold voltage, and transmit the upper limit voltage comparison result to the controller;

[0012] The lower limit detection circuit is configured to collect the lower limit output voltage of the second photoelectric detection probe, compare the lower limit output voltage with the lower limit threshold voltage, and transmit the lower limit voltage comparison result to the controller.

[0013] In one embodiment, the upper limit detection circuit includes: an upper limit amplification circuit and an upper limit comparison circuit, wherein,

[0014] The upper limit amplification circuit is respectively connected to the first photoelectric detection probe and the upper limit comparison circuit, and the upper limit comparison circuit is respectively connected to the upper limit amplification circuit and the controller;

[0015] The upper limit amplification circuit is configured to collect the upper limit output voltage of the second photoelectric detection probe, amplify the upper limit output voltage to obtain an upper limit amplified voltage, and transmit the upper limit amplified voltage to the upper limit comparison circuit;

[0016] The upper limit comparison circuit is configured to receive the upper limit amplified voltage, compare the upper limit amplified voltage with the upper limit threshold voltage, and transmit the upper limit voltage comparison result to the controller.

[0017] In one embodiment, the upper limit amplification circuit includes: a first operational amplifier, a second operational amplifier, a first capacitor, a second capacitor, a third capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, and a first potentiometer;

[0018] The negative input terminal of the first operational amplifier is respectively connected to the first photoelectric detection probe, the first capacitor and the first resistor. The positive input terminal of the first operational amplifier is connected to the second resistor. The positive power supply terminal of the first operational amplifier is respectively connected to the third resistor and the second capacitor. The output terminal of the first operational amplifier is respectively connected to the other end of the first resistor, the other end of the first capacitor, the fourth resistor and the fixed pin of the first potentiometer. The other end of the fourth resistor is connected to the positive input terminal of the second operational amplifier and the fifth resistor. The sliding pin of the first potentiometer is connected to the third capacitor. The other end of the second resistor, the other end of the second capacitor, the other end of the third capacitor, the other end of the first potentiometer's fixed pin and the negative power supply terminal of the first operational amplifier are grounded. The other end of the third resistor is connected to the first power supply. The negative input terminal of the second operational amplifier is respectively connected to the sixth resistor and the seventh resistor. The output terminal of the second operational amplifier is respectively connected to the upper limit comparison circuit and the other end of the seventh resistor. The other end of the fifth resistor and the other end of the sixth resistor are grounded.

[0019] In one embodiment, the upper limit comparison circuit includes: an eighth resistor, a fourth capacitor, a fifth capacitor and a third operational amplifier;

[0020] One end of the eighth resistor is connected to the upper limit amplification circuit. The other end of the eighth resistor is connected to the fourth capacitor and the positive input terminal of the third operational amplifier. The negative input terminal of the third operational amplifier is respectively connected to the fifth capacitor and the controller. The output terminal of the third operational amplifier is connected to the controller. The other end of the fourth capacitor and the other end of the fifth capacitor are grounded.

[0021] In one embodiment, the lower limit detection circuit includes: a lower limit amplification circuit and a lower limit calibration comparison circuit, where

[0022] The lower limit amplification circuit is respectively connected to the second photoelectric detection probe and the lower limit calibration comparison circuit. The lower limit calibration comparison circuit is respectively connected to the lower limit calibration circuit and the controller;

[0023] The lower limit amplification circuit is configured to collect the lower limit output voltage of the second photoelectric detection probe, amplify the upper limit output voltage to obtain a lower limit amplified voltage, and transmit the lower limit amplified voltage to the lower limit calibration comparison circuit;

[0024] The lower limit calibration comparison circuit is configured to receive the lower limit amplified voltage, linearly calibrate the lower limit amplified voltage to obtain a lower limit calibrated voltage, compare the lower limit calibrated voltage with a lower limit threshold voltage, and transmit the lower limit voltage comparison result to the controller.

[0025] In one embodiment, the lower limit amplification circuit includes: a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a fourth operational amplifier, a fifth operational amplifier, and a second potentiometer;

[0026] The negative input terminal of the fourth operational amplifier is respectively connected to the second photoelectric detection probe, the fixed pin of the second potentiometer, the ninth resistor, and the sixth capacitor. The positive input terminal of the fourth operational amplifier is connected to the tenth resistor. The positive power supply terminal of the fourth operational amplifier is respectively connected to the eleventh resistor and the seventh capacitor. The other end of the eleventh resistor is connected to a first power supply. The output terminal of the fourth operational amplifier is respectively connected to the other end of the ninth resistor, the other end of the sixth capacitor, the other fixed pin of the second potentiometer, the sliding pin of the second potentiometer, and the twelfth resistor. The other end of the twelfth resistor is respectively connected to the positive input terminal of the fifth operational amplifier, the thirteenth resistor, and the eighth capacitor. The other end of the eighth capacitor, the other end of the seventh capacitor, and the other end of the tenth resistor are grounded. The negative input terminal of the fifth operational amplifier is respectively connected to the fourteenth resistor and the fifteenth resistor. The output terminal of the fifth operational amplifier is connected to the other end of the fifteenth resistor and the lower limit calibration comparison circuit. The other end of the thirteenth resistor and the other end of the fourteenth resistor are grounded.

[0027] In one embodiment, the lower limit calibration comparison circuit includes: a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a ninth capacitor, a sixth operational amplifier, a third potentiometer, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a seventh operational amplifier, and a MOS transistor;

[0028] One end of the sixteenth resistor is connected to the lower limit amplifying circuit, and the other end of the sixteenth resistor is connected to the ninth capacitor and the positive input terminal of the sixth operational amplifier. The negative input terminal of the sixth operational amplifier is connected to the sliding pin of the third potentiometer. The output terminal of the sixth operational amplifier is connected to the seventeenth resistor, and the other end of the seventeenth resistor is connected to the eighteenth resistor and the fixed pin of the third potentiometer. The other end of the eighteenth resistor is connected to the nineteenth resistor and the other fixed pin of the third potentiometer. The other ends of the nineteenth resistor and the ninth capacitor are grounded. The twentieth resistor is connected to the twenty-first resistor and the positive input terminal of the seventh operational amplifier, and the other end of the twentieth resistor is connected to the output terminal of the sixth operational amplifier. The negative input terminal of the seventh operational amplifier is connected to the controller. The output terminal of the seventh operational amplifier is connected to the twenty-second resistor and the gate of the MOS transistor. The drain of the MOS transistor is connected to the controller and the twenty-third resistor. The other end of the twenty-third resistor is connected to the second power supply. The other end of the twenty-second resistor, the source of the MOS transistor, and the other end of the twenty-first resistor are grounded.

[0029] In one embodiment, the current detection circuit includes: a twenty-fourth resistor, an eighth operational amplifier, and a diode.

[0030] The twenty-fourth resistor is connected to the second photodetector probe, and the other end of the twenty-fourth resistor is connected to the positive input terminal of the eighth operational amplifier. The negative input terminal of the eighth operational amplifier is connected to the controller. The output terminal of the eighth operational amplifier is connected to the positive electrode of the diode, and the negative electrode of the diode is connected to the controller.

[0031] The present invention also provides a laser, which includes the photodetector circuit as described above.

[0032] The technical solution of the present utility model's optoelectronic detection circuit includes: a current detection circuit, an optical path detection circuit, and a controller; the current detection circuit is respectively connected to the optoelectronic detection probe in the laser and the controller, and the optical path detection circuit is respectively connected to the optoelectronic detection probe and the controller; the current detection circuit is used to detect the detection current of the optoelectronic detection probe, compare the detection current with the threshold current, and transmit the current comparison result to the controller; the optical path detection circuit is used to collect the output voltage of the optoelectronic detection probe, compare the output voltage with the threshold voltage, and transmit the voltage comparison result to the controller; the controller is used to determine the output state of the laser according to the current comparison result and the voltage comparison result. The optoelectronic detection circuit provided by the present utility model converts the optical signal into a voltage signal through the optoelectronic detection probe. The optical path detection circuit detects the voltage of the optoelectronic detection probe and compares it with the threshold voltage. The current detection circuit detects the current of the optoelectronic detection probe and compares it with the threshold current. The controller combines the comparison results of the optical path detection circuit and the current detection circuit to judge the optical path state. Description of the Drawings

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on the structures shown in these drawings.

[0034] Figure 1 It is a schematic block diagram of an embodiment of the optoelectronic detection circuit provided by the present utility model;

[0035] Figure 2 It is a schematic structural diagram of the first embodiment of the optoelectronic detection circuit provided by the present utility model;

[0036] Figure 3 It is a schematic structural diagram of the second embodiment of the optoelectronic detection circuit provided by the present utility model;

[0037] Figure 4 It is a schematic structural diagram of the third embodiment of the optoelectronic detection circuit provided by the present utility model;

[0038] Figure 5 It is a schematic structural diagram of an embodiment of the optoelectronic detection circuit provided by the present utility model.

[0039] Explanation of the Reference Numerals in the Drawings:

[0040]

[0041]

[0042] The realization, functional features and advantages of the present utility model will be further described in conjunction with the embodiments and with reference to the accompanying drawings. Specific embodiments

[0043] It should be understood that the specific embodiments described herein are merely used to explain the present utility model and are not used to limit the present utility model.

[0044] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0045] It should be noted that if there are directional indications (such as up, down, left, right, front, back,...) involved in the embodiments of the present utility model, the directional indications are only used to explain the relative positional relationship and movement conditions between components in a specific posture. If the specific posture changes, the directional indications will also change accordingly.

[0046] In addition, if there are descriptions such as "first", "second", etc. involved in the embodiments of the present utility model, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one such feature. In addition, if "and / or" or "and / or" appears throughout the text, its meaning includes three parallel solutions. Taking "A and / or B" as an example, it includes solution A, solution B, or a solution where A and B are satisfied simultaneously. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.

[0047] Currently, the internal optical path of picosecond lasers is a pure optical solution, that is, there is no optical path detection. Since the optical system of the laser is an LD seed source (seed source) + xenon lamp amplification structure, during the light output process, the light intensities at each stage are different. Among them, the seed light (the light emitted by the seed source) is the weakest, and the light energy after being amplified by the xenon lamp is the strongest. However, when the entire system is running, each path of light lacks a photoelectric signal detection device, making it impossible to collect the optical signals at each node in real time during the test, and thus unable to monitor the state of the optical path.

[0048] Due to the relatively complex optical path inside the laser, it brings certain difficulties to optical detection. For picosecond lasers, which are pulsed lasers, only the light at some internal nodes of each laser needs to be collected to achieve the purpose of monitoring optical signals. According to the optical structure of the currently used laser, referring to Figure 5 , the path of the optical path is that the light is emitted from the seed source, filtered by the isolator, amplified by the xenon lamp, and then passes through the YAG crystal to change the wavelength of the light, and reaches the treatment window through the reflection of the mirror. At this time, photodiode (Photo-Diode, PD) photodetector probes 100 are placed at the positions of the LD seed source, the output end of the isolator, after the xenon lamp amplification, and the mirror respectively. Among them, for the light amplified by the xenon lamp, a large-sensitivity PD can be used for detection, and small-sensitivity PDs are used for detection at other positions. The PD signals are amplified and transmitted to the controller (Field Programmable Gate Array, FPGA) through the signal acquisition board for processing. Therefore, when the optical path at a certain point in the laser system is abnormal, the corresponding photosensitive PD can quickly detect the light intensity at this time. After comparison and judgment by the controller 400 and the threshold of the upper computer, the abnormal point of the optical path can be quickly located and real-time alarm can be realized, which improves the reliability of the laser system to a certain extent and protects the laser and personal safety.

[0049] The present utility model proposes an optoelectronic detection circuit.

[0050] Please refer to Figure 1 , in an embodiment of the present utility model, the optoelectronic detection circuit includes: a current detection circuit 300, an optical path detection circuit 200, and a controller 400; the current detection circuit is respectively connected to the photodetector probe 100 inside the laser and the controller 400, and the optical path detection circuit 200 is respectively connected to the photodetector probe 100 and the controller 400; the current detection circuit 300 is used to detect the detection current of the photodetector probe, compare the detection current with the threshold current, and transmit the current comparison result to the controller; the optical path detection circuit 200 is used to collect the output voltage of the photodetector probe, compare the output voltage with the threshold voltage, and transmit the voltage comparison result to the controller; the controller 400 is used to determine the output state of the laser according to the current comparison result and the voltage comparison result. The optoelectronic detection circuit provided by the present utility model converts the optical signal into a voltage signal through the photodetector probe. The optical path detection circuit detects the voltage of the photodetector probe and compares it with the threshold voltage, and the current detection circuit detects the current of the photodetector probe and compares it with the threshold current. The controller combines the comparison results of the optical path detection circuit and the current detection circuit to judge the optical path state.

[0051] It should be noted that the photoelectric detection probe 100 is a photodetector. A photodetector is a PN junction with an externally applied reverse bias voltage. When incident light acts, stimulated absorption occurs to generate photo-generated electron-hole pairs. These electron-hole pairs form a drift current under the action of the built-in electric field in the depletion layer. At the same time, some electron-hole pairs on both sides of the depletion layer enter the depletion layer due to diffusion motion and form a diffusion current under the action of the electric field. The sum of these two parts of the current is the photo-generated current. Photodetectors include photomultiplier tubes (PMT), photodiodes (PD), avalanche photodiodes (APD), and silicon photomultipliers (MPPC / SiPM), etc. In this application, the photoelectric detection probe 100 takes the photodiode (PD) as an example.

[0052] Optionally, the controller 400 is a master control device that controls the start, speed regulation, braking, and reverse of a motor by changing the wiring of the main circuit or control circuit and changing the resistance value in the circuit in a predetermined order. It consists of a program counter, an instruction register, an instruction decoder, a timing generator, and an operation controller. It is the "decision-making body" that issues commands, that is, it completes the coordination and command of the operation of the entire computer system. The controller includes an MCU chip, a PAL chip, an FPGA chip, etc. Considering cost in this application, it may be implemented through ARM, but for lasers, it has no advantage in terms of speed. Using an FPGA can perform high-speed processing on weak photoelectric signals and meet the optical path detection requirements of current product applications. Therefore, the controller 400 in this application preferentially selects an FPGA.

[0053] The present utility model connects the optical path detection circuit and the current detection circuit as a judgment condition for whether the optical path of the entire laser system is operating normally. The current detection circuit and the optical path detection circuit form an AND gate relationship in the judgment logic, that is, after a certain time after the current detection signal is triggered, if the signal of the optical path detection circuit is also triggered, then it can be used as a true photoelectric detection judgment at this time.

[0054] In this embodiment, the photodiode PD of the photoelectric detection probe 100 detects the optical signal in the laser. The stronger the optical signal, the higher the voltage of the photodiode PD. By detecting the voltage value of the PD photoelectric detection probe 100, the intensity of the optical signal at the place detected by the PD photoelectric detection probe can be judged. The optical path detection circuit 200 detects the voltage of the PD photoelectric detection probe as the detection voltage. The detection voltage can be compared with the threshold voltage to determine whether the detected optical signal is within the working range required by the laser, and the voltage comparison result is transmitted to the controller 400. The detection current detected by the current detection circuit is compared with the threshold current, and the current comparison result is transmitted to the controller 400. The controller 400 combines the current comparison result and the voltage comparison result to determine whether to adjust the light output intensity of the LD seed source + xenon lamp amplification structure of the laser.

[0055] Figure 2 It is the circuit diagram of the first embodiment of the optoelectronic detection circuit proposed by the embodiment of the present utility model.

[0056] The optical path detection circuit includes: an upper limit detection circuit and a lower limit detection circuit. Among them, the optoelectronic detection probe 100 includes a first optoelectronic detection probe 110 and a second optoelectronic detection probe 120. The first optoelectronic detection probe 110 is located on the optical path after the light is amplified, and the second optoelectronic detection probe 120 is located on the optical path where the light is not amplified. The upper limit detection circuit is respectively connected to the controller and the first optoelectronic detection probe 110, and the lower limit detection circuit is respectively connected to the controller and the second optoelectronic detection probe 120. The upper limit detection circuit is used to collect the upper limit output voltage of the first optoelectronic detection probe 110, compare the upper limit output voltage with the upper limit threshold voltage, and transmit the upper limit voltage comparison result to the controller. The lower limit detection circuit is used to collect the lower limit output voltage of the second optoelectronic detection probe 120, compare the lower limit output voltage with the lower limit threshold voltage, and transmit the lower limit voltage comparison result to the controller.

[0057] It should be noted that after the light is amplified by the xenon lamp, its energy becomes larger, and the voltage generated by the corresponding optoelectronic detection probe 100 after being irradiated is relatively high. When the light is emitted from the seed source and is not amplified by the xenon lamp and directly irradiates the optoelectronic detection probe 100, the voltage corresponding to the optoelectronic detection probe 100 after being irradiated is relatively low at this time. In a specific embodiment, the energy of the laser before amplification is less than 100 mJ (millijoule), and the voltage corresponding to it after being irradiated by the optoelectronic detection probe 100 is less than or equal to 2.5 V. When the light is further amplified by the xenon lamp, its energy can be as high as 20 J (joule), and when it irradiates the optoelectronic detection probe 100 again, the corresponding voltage can reach 10 V. The level difference between the two is relatively large. Therefore, if the same optical path detection circuit is used to judge whether the voltages of the two meet the preset standards, there will be a relatively large error. Therefore, when lasers with different energies are irradiated on the optoelectronic detection probe 100, different detection circuits and different types of optoelectronic detection probes are used to determine the output state of the laser on the corresponding optical path. In other specific embodiments, the voltages corresponding to the optoelectronic detection probes located before and after the light amplification may be different from those in the above embodiments, but in the same embodiment, the voltage values corresponding to the same type of optoelectronic detection probes before and after the light amplification must have a difference of several times or even more than 20 times.

[0058] It should be noted that Figure 2 is the upper limit detection circuit, Figure 3It is a lower limit detection circuit. The first photoelectric detection probe 110 is a large photosensitive PD, and the second photoelectric detection probe 120 is a small photosensitive PD. Among them, the large photosensitive PD is installed at the output ends of the second and third amplification stages of the xenon lamp at the strong light node and at the output mirror of the light outlet, and the small photosensitive PD is installed at the output end of the laser diode (LD) seed source at the weak light node and at the output end of the isolator.

[0059] It can be understood that taking the example of before and after the amplification of the xenon lamp inside the laser, the light intensity after the amplification of the xenon lamp is very high, and a large photosensitive PD needs to be placed for detection to check whether the light intensity after the amplification of the xenon lamp exceeds the light intensity required for the normal operation of the laser. At the same time, the upper limit detection circuit is connected to the large photosensitive PD. The upper limit detection circuit is used to detect whether the optical signal after the amplification of the xenon lamp is too strong. When the optical signal after the amplification of the xenon lamp is too strong, the large photosensitive PD converts the optical signal into an electrical signal. As the optical signal increases, the voltage detected by the upper limit detection circuit increases. When it exceeds the upper limit threshold voltage, the upper limit detection circuit transmits the upper limit voltage comparison result to the controller. The controller receives the voltage comparison result and judges that the optical signal after the amplification of the xenon lamp is abnormally strong, and then adjusts the intensity of the xenon lamp to weaken the optical signal.

[0060] The upper limit detection circuit includes: an upper limit amplification circuit 211 and an upper limit comparison circuit 212. Among them, the upper limit amplification circuit 211 is respectively connected to the first photoelectric detection probe 110 and the upper limit comparison circuit 212, and the upper limit comparison circuit 212 is respectively connected to the upper limit amplification circuit 211 and the controller 400; the upper limit amplification circuit 211 is used to collect the upper limit output voltage of the first photoelectric detection probe 110, amplify the upper limit output voltage to obtain an upper limit amplified voltage, and transmit the upper limit amplified voltage to the upper limit comparison circuit; the upper limit comparison circuit 212 is used to receive the upper limit amplified voltage, compare the upper limit amplified voltage with the upper limit threshold voltage, and transmit the upper limit voltage comparison result to the controller.

[0061] It should be noted that the voltage detected by the first photoelectric detection probe 110 is very small and needs to be amplified. The upper limit amplified voltage obtained by amplifying the upper limit output voltage through the upper limit amplification circuit 211 is compared with the upper limit threshold voltage. When the upper limit amplified voltage is greater than the upper limit threshold voltage, the controller judges that the light intensity at the large photosensitive PD is too strong and needs to adjust the optical signal output of the laser. When the upper limit amplified voltage is less than the upper limit threshold voltage, the controller 400 judges that the light intensity at the large photosensitive PD is normal, and the large photosensitive PD continues to detect the light intensity.

[0062] The upper limit amplification circuit 211 includes: a first operational amplifier A1, a second operational amplifier A2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and a first potentiometer B1; the negative input terminal of the first operational amplifier is respectively connected to the first photodetector probe 110, the first capacitor, and the first resistor, the positive input terminal of the first operational amplifier is connected to the second resistor, the positive power supply terminal of the first operational amplifier is respectively connected to the third resistor and the second capacitor, the output terminal of the first operational amplifier is respectively connected to the other end of the first resistor, the other end of the first capacitor, the fourth resistor, and the fixed pin of the first potentiometer, the other end of the fourth resistor is connected to the positive input terminal of the second operational amplifier and the fifth resistor, the sliding pin of the first potentiometer is connected to the third capacitor, the other end of the second resistor, the other end of the second capacitor, the other end of the third capacitor, the other fixed pin of the first potentiometer, and the negative power supply terminal of the first operational amplifier are grounded, the other end of the third resistor is connected to the first power supply VCC1, the negative input terminal of the second operational amplifier is respectively connected to the sixth resistor R6 and the seventh resistor R7, the output terminal of the second operational amplifier is respectively connected to the upper limit comparison circuit and the other end of the seventh resistor, and the other ends of the fifth resistor and the sixth resistor are grounded.

[0063] It should be noted that the voltage of the first power supply VCC1 is 5V, the voltage of the second power supply VCC2 is 3.3V. The specific models of the first operational amplifier A1 and the second operational amplifier A2 can be set according to the actual detection requirements of the circuit. PD_UP is the upper limit output voltage of the first photodetector probe 110. The specific model of the first potentiometer B1 can be set according to the actual detection requirements of the circuit. The data is stored separately in the EEPROM and is not easily lost.

[0064] It can be understood that PD_UP is amplified by the first operational amplifier A1 to obtain a first-stage amplified voltage UP_OUT1, and the first-stage amplified voltage UP_OUT1 is amplified by the second operational amplifier A2 to obtain an upper limit amplified voltage UP_OUT2. UP_OUT2 = (1 + R7 / R6)UP_OUT1. The upper limit amplified voltage UP_OUT2 is output to the upper limit comparison circuit 212.

[0065] The upper limit comparison circuit 212 includes: an eighth resistor R8, a fourth capacitor C4, a fifth capacitor C5, and a third operational amplifier A3; one end of the eighth resistor is connected to the upper limit amplification circuit, the other end of the eighth resistor is connected to the fourth capacitor and the positive input terminal of the third operational amplifier, the negative input terminal of the third operational amplifier is respectively connected to the fifth capacitor and the controller, the output terminal of the third operational amplifier is connected to the controller, and the other ends of the fourth capacitor and the fifth capacitor are grounded.

[0066] It should be noted that SET_UP is the upper limit voltage threshold, and the upper limit threshold voltage SET_UP can be set by connecting to the controller or can also be set by connecting to a digital-to-analog converter.

[0067] It can be understood that the third operational amplifier A3 compares the upper limit amplified voltage UP_OUT2 with the upper limit voltage threshold SET_UP and transmits the comparison result to the controller 400. When the upper limit amplified voltage UP_OUT2 is greater than the upper limit threshold voltage SET_UP, the controller 400 receives a high level, and the controller 400 determines that the light intensity at the large photosensitive PD is too strong and needs to adjust the optical signal output of the laser. When the upper limit amplified voltage UP_OUT2 is less than the upper limit threshold voltage SET_UP, the controller 400 receives a low level, and the controller 400 determines that the light intensity at the large photosensitive PD is normal, and the large photosensitive PD continues to detect the light intensity.

[0068] Optionally, the resistor, as a circuit protection component, divides the power supply voltage into different levels to meet the working requirements of different circuit components, and can be replaced by iron wire and copper wire. The capacitor is used for filtering and voltage stabilization.

[0069] In this embodiment, the first photoelectric detection probe 110 is a large photosensitive PD. The large photosensitive PD converts the optical signal into an upper limit output voltage PD_UP. The upper limit output voltage PD_UP collected in real time by the upper limit amplification circuit 211 is used as the input signal of the first operational amplifier A1. After being amplified by the first operational amplifier A1, a primary amplified voltage UP_OUT1 is obtained. It is adjusted by connecting to the output terminal of the first operational amplifier A1 through the first potentiometer B1. The data is stored separately in the EEPROM and is not easily lost. The primary amplified voltage UP_OUT1 is amplified by the second operational amplifier A2 to obtain an upper limit amplified voltage UP_OUT2. The upper limit amplified voltage UP_OUT2 is output to the third operational amplifier A3 to be compared with the upper limit threshold voltage SET_UP and then output to the controller 400.

[0070] As Figure 3 shown, it is the circuit structure diagram of the second embodiment of the photoelectric detection circuit proposed by the embodiment of the present invention.

[0071] Based on the above first embodiment, the second embodiment of the optoelectronic detection circuit of the present invention is proposed.

[0072] It can be understood that the optical path detection circuit 200 further includes a lower limit detection circuit. Figure 3 The lower limit detection circuit is provided, and the second optoelectronic detection probe 120 is a small photosensitive PD, and the small photosensitive PD is installed at the output end of the weak light node laser LD seed source and the output end of the isolator.

[0073] It should be noted that taking the output end of the isolator as an example, the light intensity at the output end of the isolator inside the laser is weak, so a small photosensitive PD is needed to detect the optical signal. The small photosensitive PD is used to check the optical signal at the output end of the isolator. The small photosensitive PD is connected to the lower limit detection circuit, and the small photosensitive PD converts the optical signal at the output end of the isolator into a lower limit output voltage and transmits it to the lower limit detection circuit. The lower limit detection circuit is used to compare the lower limit output voltage with the lower limit threshold voltage and transmit the comparison result to the controller. When the lower limit output voltage is greater than the lower limit threshold voltage, the controller 400 determines that the optical signal at the output end of the isolator is normal. When the lower limit output voltage is less than the lower limit threshold voltage, the controller 400 determines that the optical signal at the output end of the isolator is abnormally dark.

[0074] The lower limit detection circuit includes: a lower limit amplification circuit 221 and a lower limit calibration comparison circuit 222. Among them, the lower limit amplification circuit 221 is respectively connected to the second optoelectronic detection probe 120 and the lower limit calibration comparison circuit 222, and the lower limit calibration comparison circuit is respectively connected to the lower limit calibration comparison circuit and the controller 400; the lower limit amplification circuit 221 is used to collect the lower limit output voltage of the second optoelectronic detection probe 120, amplify the upper limit output voltage to obtain a lower limit amplified voltage, and transmit the lower limit amplified voltage to the lower limit calibration comparison circuit; the lower limit calibration comparison circuit 222 is used to receive the lower limit amplified voltage, perform linear calibration on the lower limit amplified voltage to obtain a lower limit calibrated voltage, compare the lower limit calibrated voltage with the lower limit threshold voltage, and transmit the lower limit voltage comparison result to the controller.

[0075] It can be understood that the voltage of the small photosensitive PD of the second optoelectronic detection probe 120 is very small and needs to be amplified. And because the optical signal is too weak, the small photosensitive PD may detect inaccurately, so calibration is also required. The lower limit amplified voltage is divided and followed as the actual voltage. This voltage is related to the corresponding linear power and energy, that is, the lower limit calibrated voltage. According to the comparison between the lower limit calibrated voltage and the lower limit threshold voltage, it is output to the controller 400 for judgment. When the lower limit calibrated voltage is greater than the lower limit threshold voltage, the controller 400 determines that the optical signal at the output end of the isolator is normal. When the lower limit calibrated voltage is less than the lower limit threshold voltage, the controller 400 determines that the optical signal at the output end of the isolator is abnormal.

[0076] It should be noted that when the controller 400 determines that the optical signal at the output end of the isolator is abnormal, it is also necessary to combine the current detection circuit to determine whether to adjust the light source at the output end of the isolator.

[0077] The lower limit amplification circuit includes: a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a fourteenth resistor R14, a fifteenth resistor R15, a sixth capacitor C6, a seventh capacitor C7, an eighth capacitor C8, a fourth operational amplifier A4, a fifth operational amplifier A5, and a second potentiometer B2; the negative input terminal of the fourth operational amplifier A4 is respectively connected to the second photodetector probe 120, the fixed pin of the second potentiometer B2, the ninth resistor R9, and the sixth capacitor C6, the positive input terminal of the fourth operational amplifier A4 is connected to the tenth resistor R10, the positive power supply of the fourth operational amplifier A4 is respectively connected to the eleventh resistor R11 and the seventh capacitor C7, the other end of the eleventh resistor R11 is connected to the first power supply VCC1, the output terminal of the fourth operational amplifier is respectively connected to the other end of the ninth resistor, the other end of the sixth capacitor, the other fixed pin of the second potentiometer B2, the sliding pin of the second potentiometer, and the twelfth resistor R12, the other end of the twelfth resistor R12 is respectively connected to the positive input terminal of the fifth operational amplifier A5, the thirteenth resistor R13, and the eighth capacitor C8, the other end of the eighth capacitor, the other end of the seventh capacitor C7, and the other end of the tenth resistor R10 are grounded, the negative input terminal of the fifth operational amplifier A5 is respectively connected to the fourteenth resistor and the fifteenth resistor, the output terminal of the fifth operational amplifier is connected to the other end of the fifteenth resistor R15 and the lower limit calibration comparison circuit 222, and the other end of the thirteenth resistor and the other end of the fourteenth resistor R14 are grounded.

[0078] It should be noted that PD_DOWN is the lower limit output voltage of the small photosensitive PD.

[0079] It can be understood that the lower limit output voltage PD_DOWN is amplified by the fourth operational amplifier A4 to obtain a first-stage lower limit amplified voltage OUT1_DOWN, and the first-stage lower limit amplified voltage OUT1_DOWN is amplified by the fifth operational amplifier A5 to obtain a lower limit amplified voltage OUT2_DOWN. OUT2_DOWN = OUT1_DOWN(1 + R15 / R14). The lower limit amplified voltage OUT2_DOWN is transmitted to the lower limit calibration comparison circuit.

[0080] The lower limit calibration comparison circuit includes: the sixteenth resistor R16, the seventeenth resistor R17, the eighteenth resistor R18, the nineteenth resistor R19, the ninth capacitor C9, the sixth operational amplifier A6, the third potentiometer B3, the twentieth resistor R20, the twenty-first resistor R21, the twenty-second resistor R22, the twenty-third resistor R23, the seventh operational amplifier A7, and the MOS transistor Q1; one end of the sixteenth resistor R16 is connected to the lower limit amplification circuit, the other end of the sixteenth resistor R16 is connected to the ninth capacitor and the positive input terminal of the sixth operational amplifier, the negative input terminal of the sixth operational amplifier is connected to the sliding pin of the third potentiometer, the output terminal of the sixth operational amplifier is connected to the seventeenth resistor R17, the other end of the seventeenth resistor R17 is connected to the eighteenth resistor and the fixed pin of the third potentiometer, the other end of the eighteenth resistor R18 is connected to the nineteenth resistor R19 and the other fixed pin of the third potentiometer B3, and the other ends of the nineteenth resistor and the ninth capacitor are grounded; the twentieth resistor is connected to the twenty-first resistor R21 and the positive input terminal of the seventh operational amplifier A7, the other end of the twentieth resistor R20 is connected to the output terminal of the sixth operational amplifier, the negative input terminal of the seventh operational amplifier A7 is connected to the controller, the output terminal of the seventh operational amplifier is connected to the twenty-second resistor R22 and the gate of the MOS transistor Q1, the drain of the MOS transistor Q1 is connected to the controller and the twenty-third resistor R23, the other end of the twenty-third resistor R23 is connected to the second power supply VCC2, and the other ends of the twenty-second resistor R22, the source of the MOS transistor Q1, and the twenty-first resistor R21 are grounded.

[0081] It can be understood that the MOS transistor is an NMOS transistor, and SET_DOWN is the lower limit threshold voltage.

[0082] It should be noted that the lower limit amplified voltage OUT2_DOWN is divided and followed by the sixth operational amplifier A6 to be stabilized at the lower limit calibration voltage. Because the optical signal at the output end of the isolator is too weak, the lower limit output voltage detected by the small photosensitive PD is unstable, and the amplified lower limit amplified voltage OUT2_DOWN is also unstable, and there may be phenomena such as sometimes high, sometimes low, sometimes present, and sometimes absent. The sixth operational amplifier calibrates the lower limit amplified voltage OUT2_DOWN to the lower limit calibration voltage, and the seventh operational amplifier A7 compares the lower limit calibration voltage with the lower limit threshold voltage. When the lower limit calibration voltage is greater than the lower limit threshold voltage, the seventh operational amplifier outputs a high voltage, the MOS transistor Q1 conducts, the controller receives a low level, and the controller 400 determines that the optical signal at the output end of the isolator is normal; when the lower limit calibration voltage is less than the lower limit threshold voltage, the seventh operational amplifier A7 outputs a low voltage, the MOS transistor Q1 is cut off, the controller 400 receives a high level, and the controller 400 determines that the optical signal at the output end of the isolator is abnormal.

[0083] Optionally, the lower threshold voltage SET_DOWN can be set by connecting to a controller or a digital-to-analog converter.

[0084] In this embodiment, the lower output voltage collected in real time by the small photosensitive PD serves as the input signal of the fourth operational amplifier A4. The second potentiometer B2 is connected across the two ends of the fourth operational amplifier A4, that is, the input and output ends are adjusted. Its output is amplified by the subsequent fifth operational amplifier A5 to obtain the lower amplified voltage as the non-inverting input of the next-stage sixth operational amplifier A6. The inverting input voltage is set through the third potentiometer B3. Then, the lower amplified voltage is divided and followed to serve as the actual voltage of PD_Down. This voltage is related to the corresponding linear power and energy, that is, the lower calibration voltage. This value is compared with the lower voltage threshold and output to the controller 400 for judgment.

[0085] As Figure 4 shown, the circuit structure diagram of the third embodiment of the photoelectric detection circuit proposed in the embodiment of the present invention.

[0086] Based on the above second embodiment, the third embodiment of the photoelectric detection circuit of the present invention is proposed.

[0087] The current detection circuit includes: a twenty-fourth resistor R24, an eighth operational amplifier A8, and a diode Q2; the twenty-fourth resistor R24 is connected to the second photoelectric detection probe 120, the other end of the twenty-fourth resistor R24 is connected to the positive input end of the eighth operational amplifier A8, the negative input end of the eighth operational amplifier is connected to the controller 400, the output end of the eighth operational amplifier A8 is connected to the positive electrode of the diode Q2, and the negative electrode of the diode Q2 is connected to the controller.

[0088] It can be understood that the second photoelectric detection probe 120 is a small photosensitive PD, and the diode Q2 is used to prevent the current from flowing back to the controller. OC_SET is the threshold current.

[0089] Optionally, the threshold current OC_SET can be set by connecting to a digital-to-analog converter or by the controller.

[0090] It should be noted that the current detection circuit 300 detects the current of the small photosensitive PD. When the detected current is greater than the threshold current OC_SET, the eighth operational amplifier A8 outputs a high level, and the controller determines that the optical signal received by the small photosensitive PD is normal; when the detected current is less than the threshold current OC_SET, the eighth operational amplifier A8 outputs a low level, and the controller determines that the small photosensitive PD is operating abnormally. After a certain time after the current detection signal is triggered, if the lower limit detection circuit signal is also triggered, and the controller 400 receives the high level signal output by the lower limit detection circuit, then at this time, it can be used as a true photoelectric detection judgment, and the controller determines that the light intensity at the output end of the isolator is too weak, and the brightness of the LD seed source needs to be adjusted.

[0091] In this embodiment, the lower limit detection circuit is connected to the current detection circuit. After a certain time after the current detection circuit signal is triggered, if the signal of the lower limit detection circuit is also triggered, then at this time, it can be determined that the light intensity output by the small photosensitive PD is too weak, and the light source inside the laser needs to be adjusted. Because the light intensity at the small photosensitive PD is too weak, the small photosensitive PD may be unable to detect or detect incorrectly. The present invention adds a current detection circuit on the basis of the photoelectric detection circuit, making the lower limit detection at the small photosensitive PD more accurate.

[0092] It should be noted that in this article, the term "including", "comprising" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or system including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or system. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or system including that element.

[0093] The present invention also proposes a laser, which includes a photoelectric detection circuit. The specific structure of the photoelectric detection circuit refers to the above embodiment. Since this laser adopts all the technical solutions of the above all embodiments, it has at least all the beneficial effects brought by the technical solutions of the above embodiments, and will not be elaborated here one by one.

[0094] The above is only an exemplary embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent structural transformation made under the technical concept of the present invention by using the content of the specification and drawings of the present invention, or directly / indirectly applied in other related technical fields, is included in the patent protection scope of the present invention.

Claims

1. A photoelectric detection circuit, characterized in that: The photoelectric detection circuit includes: a current detection circuit, an optical path detection circuit and a controller; The current detection circuit is respectively connected to the photoelectric detection probe in the laser and the controller, and the optical path detection circuit is respectively connected to the photoelectric detection probe and the controller; The current detection circuit is used to detect the detection current of the photoelectric detection probe, compare the detection current with the threshold current, and transmit the current comparison result to the controller; The optical path detection circuit is used to collect the output voltage detected by the photoelectric detection probe, compare the output voltage with a threshold voltage, and transmit the voltage comparison result to the controller; The controller is used to determine the output state of the laser according to the current comparison result and the voltage comparison result.

2. The photoelectric detection circuit according to claim 1, characterized in that: The optical path detection circuit includes: an upper limit detection circuit and a lower limit detection circuit, wherein the photoelectric detection probe includes a first photoelectric detection probe and a second photoelectric detection probe, the first photoelectric detection probe is located on the optical path after the light is amplified, and the second photoelectric detection probe is located on the optical path before the light is amplified; The upper limit detection circuit is connected to the controller and the first photoelectric detection probe respectively, and the lower limit detection circuit is connected to the controller and the second photoelectric detection probe respectively; The upper limit detection circuit is used to collect the upper limit output voltage of the first photoelectric detection probe, compare the upper limit output voltage with the upper limit threshold voltage, and transmit the upper limit voltage comparison result to the controller; The lower limit detection circuit is used to collect the lower limit output voltage of the second photoelectric detection probe, compare the lower limit output voltage with the lower limit threshold voltage, and transmit the lower limit voltage comparison result to the controller.

3. The photoelectric detection circuit according to claim 2, characterized in that: The upper limit detection circuit includes: an upper limit amplification circuit and an upper limit comparison circuit, wherein: The upper limit amplification circuit is respectively connected to the first photoelectric detection probe and the upper limit comparison circuit, and the upper limit comparison circuit is respectively connected to the upper limit amplification circuit and the controller; The upper limit amplification circuit is used to collect the upper limit output voltage of the first photoelectric detection probe, amplify the upper limit output voltage to obtain an upper limit amplified voltage, and transmit the upper limit amplified voltage to the upper limit comparison circuit; The upper limit comparison circuit is used to receive the upper limit amplified voltage, compare the upper limit amplified voltage with an upper limit threshold voltage, and transmit the upper limit voltage comparison result to the controller.

4. The photoelectric detection circuit according to claim 3, characterized in that: The upper limit amplification circuit comprises: a first operational amplifier, a second operational amplifier, a first capacitor, a second capacitor, a third capacitor, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor and a first potentiometer; The negative input terminal of the first operational amplifier is respectively connected to the first photoelectric detection probe, the first capacitor and the first resistor, the positive input terminal of the first operational amplifier is connected to the second resistor, the positive power supply terminal of the first operational amplifier is respectively connected to the third resistor and the second capacitor, the output terminal of the first operational amplifier is respectively connected to the other end of the first resistor, the other end of the first capacitor, the fourth resistor and the fixed pin of the first potentiometer, the other end of the fourth resistor is connected to the positive input terminal of the second operational amplifier and the fifth resistor, the sliding pin of the first potentiometer is connected to the third capacitor, the other end of the second resistor, the other end of the second capacitor, the other end of the third capacitor, the other fixed pin of the first potentiometer and the negative power supply terminal of the first operational amplifier are grounded, the other end of the third resistor is connected to the first power supply, the negative input terminal of the second operational amplifier is respectively connected to the sixth resistor and the seventh resistor, the output terminal of the second operational amplifier is respectively connected to the upper limit comparison circuit and the other end of the seventh resistor, the other end of the fifth resistor and the other end of the sixth resistor are grounded.

5. The photoelectric detection circuit according to claim 3, characterized in that: The upper limit comparison circuit comprises: an eighth resistor, a fourth capacitor, a fifth capacitor and a third operational amplifier; One end of the eighth resistor is connected to the upper limit amplifier circuit, the other end of the eighth resistor is connected to the fourth capacitor and the positive input end of the third operational amplifier, the negative input end of the third operational amplifier is respectively connected to the fifth capacitor and the controller, the output end of the third operational amplifier is connected to the controller, and the other end of the fourth capacitor and the other end of the fifth capacitor are grounded.

6. The photoelectric detection circuit according to claim 2, characterized in that: The lower limit detection circuit includes: a lower limit amplification circuit and a lower limit calibration comparison circuit, wherein: The lower limit amplification circuit is respectively connected to the second photoelectric detection probe and the lower limit calibration comparison circuit, and the lower limit calibration comparison circuit is respectively connected to the lower limit calibration comparison circuit and the controller; The lower limit amplifier circuit is used to collect the lower limit output voltage of the second photoelectric detection probe, amplify the upper limit output voltage to obtain the lower limit amplified voltage, and transmit the lower limit amplified voltage to the lower limit calibration comparison circuit; The lower limit calibration comparison circuit is used to receive the lower limit amplified voltage, perform linear calibration on the lower limit amplified voltage to obtain a lower limit calibration voltage, compare the lower limit calibration voltage with a lower limit threshold voltage, and transmit the lower limit voltage comparison result to the controller.

7. The photoelectric detection circuit according to claim 6, characterized in that: The lower limit amplification circuit includes: a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a thirteenth resistor, a fourteenth resistor, a fifteenth resistor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a fourth operational amplifier, a fifth operational amplifier and a second potentiometer; The negative input terminal of the fourth operational amplifier is respectively connected to the second photoelectric detection probe, the fixed pin of the second potentiometer, the ninth resistor and the sixth capacitor, the positive input terminal of the fourth operational amplifier is connected to the tenth resistor, the positive power supply terminal of the fourth operational amplifier is respectively connected to the eleventh resistor and the seventh capacitor, the other end of the eleventh resistor is connected to the first power supply, the output terminal of the fourth operational amplifier is respectively connected to the other end of the ninth resistor, the other end of the sixth capacitor, the other fixed pin of the second potentiometer, the sliding pin of the second potentiometer and the twelfth resistor, the other end of the twelfth resistor is respectively connected to the positive input terminal of the fifth operational amplifier, the thirteenth resistor and the eighth capacitor, the other end of the eighth capacitor, the other end of the seventh capacitor and the other end of the tenth resistor are grounded, the negative input terminal of the fifth operational amplifier is respectively connected to the fourteenth resistor and the fifteenth resistor, the output terminal of the fifth operational amplifier is connected to the other end of the fifteenth resistor and the lower limit calibration comparison circuit, the other end of the thirteenth resistor and the other end of the fourteenth resistor are grounded.

8. The photoelectric detection circuit according to claim 6, characterized in that: The lower limit calibration comparison circuit includes: a sixteenth resistor, a seventeenth resistor, an eighteenth resistor, a nineteenth resistor, a ninth capacitor, a sixth operational amplifier, a third potentiometer, a twentieth resistor, a twenty-first resistor, a twenty-second resistor, a twenty-third resistor, a seventh operational amplifier and a MOS tube; One end of the sixteenth resistor is connected to the lower limit amplifier circuit, the other end of the sixteenth resistor is connected to the ninth capacitor and the positive input end of the sixth operational amplifier, the negative input end of the sixth operational amplifier is connected to the sliding pin of the third potentiometer, the output end of the sixth operational amplifier is connected to the seventeenth resistor, the other end of the seventeenth resistor is connected to the eighteenth resistor and the fixed pin of the third potentiometer, the other end of the eighteenth resistor is connected to the nineteenth resistor and another fixed pin of the third potentiometer, and the other end of the nineteenth resistor and the ninth capacitor is grounded; the twenty-first resistor is connected to the twenty-first resistor and the positive input end of the seventh operational amplifier, the other end of the twenty-first resistor is connected to the output end of the sixth operational amplifier, the negative input end of the seventh operational amplifier is connected to the controller, the output end of the seventh operational amplifier is connected to the twenty-second resistor and the gate of the MOS tube, the drain of the MOS tube is connected to the controller and the twenty-third resistor, the other end of the twenty-third resistor is connected to the second power supply, and the other end of the twenty-second resistor, the source of the MOS tube and the other end of the twenty-first resistor are grounded.

9. The photoelectric detection circuit according to claim 2, characterized in that: The current detection circuit comprises: a twenty-fourth resistor, an eighth operational amplifier and a diode; The twenty-fourth resistor is connected to the second photoelectric detection probe, the other end of the twenty-fourth resistor is connected to the positive input of the eighth operational amplifier, the negative input of the eighth operational amplifier is connected to the controller, the output of the eighth operational amplifier is connected to the anode of the diode, and the cathode of the diode is connected to the controller.

10. A laser, characterized in that: The laser comprises the photodetection circuit according to any one of claims 1 to 9.

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