Optical path detection alarm circuit for fiber laser

Abstract

The utility model relates to an optical path detection alarm circuit for a fiber laser. The optical path detection alarm circuit comprises a photoelectric detection circuit, a pulse shaping circuit, a first synthesis circuit and a second synthesis circuit, the photoelectric detection circuit receives and amplifies an optical signal output by the laser; the pulse shaping circuit receives a laser enable signal consistent with the optical signal in frequency, and outputs a shaping signal of a TTL level under the triggering of the laser enable signal; the first synthesis circuit performs NAND logic operation on the laser enable signal and the shaping signal and outputs a first synthesis signal; and the second synthesis circuit is used for carrying out OR logic operation on the first synthesis signal and the optical signal and outputting a constant TTL level detection signal. According to the utility model, when the laser outputs quasi-continuous laser or continuous laser, a path of constant TTL level detection signal can be generated, the applicability is strong, the occupied resources are few, the circuit can detect optical signals with any frequency and any duty ratio, and a guarantee is provided for the use safety of the laser.

Description

Technical Field

[0001] The utility model relates to the technical field of optical signal detection, in particular to an alarm circuit for optical path detection of optical fiber lasers. Background Art

[0002] Fiber lasers usually have two operating modes: quasi-continuous laser and continuous laser. In quasi-continuous laser mode, the laser outputs a series of short pulses with intervals between pulses. This mode is suitable for applications that require control of laser output intensity or rapid switching. It is common in applications that require precise control of time, such as laser radar, short-distance transmission in optical communications, and laser printing. In continuous mode, the laser outputs a continuous light signal without intervals or obvious pulses. This mode is suitable for applications that require stable and continuous output, such as medical lasers, long-distance optical communications, laser processing, and other high-power applications that require stable output.

[0003] At present, the circuits used for laser optical path detection are relatively complex and are not compatible with the two modes. For example, the Chinese patent application number CN201720606601.6 discloses a laser optical path detection circuit, which is used to detect whether the optical path in the laser can generate laser normally, but the circuit is not compatible with the two working modes of the laser, quasi-continuous and continuous laser, and when the laser frequency span is large, the period of the optical signal changes greatly, and the detection will not be timely.

[0004] Therefore, it is necessary to propose an optical path detection alarm circuit for fiber lasers, which can detect optical signals at any frequency regardless of whether the laser outputs quasi-continuous laser or continuous laser, and shut down the laser in time when an abnormality occurs in the laser optical path. Utility Model Content

[0005] In view of this, it is necessary to provide an optical path detection alarm circuit for fiber lasers to solve the technical problems that the existing optical path detection technology is not compatible with the quasi-continuous and continuous laser operating modes of the laser, and that detection is not timely when the laser frequency span is large and the period changes greatly.

[0006] In order to achieve the above technical purpose, the utility model adopts the following technical solutions:

[0007] The utility model provides an optical path detection alarm circuit for a fiber laser, comprising: a photoelectric detection circuit, a pulse shaping circuit, a first synthesis circuit and a second synthesis circuit; the output end of the photoelectric detection circuit is connected to the input end of the second synthesis circuit, the output end of the pulse shaping circuit is connected to the input end of the first synthesis circuit, and the output end of the first synthesis circuit is connected to the input end of the second synthesis circuit;

[0008] The photoelectric detection circuit is used to receive and amplify the optical signal output by the laser;

[0009] The pulse shaping circuit is used to receive a laser enable signal having a frequency consistent with the optical signal, and output a TTL level shaped signal under the triggering of the laser enable signal;

[0010] The first synthesis circuit is used to perform a non-AND logic operation on the laser enable signal and the shaping signal, and output a first synthesis signal;

[0011] The second synthesis circuit is used to perform an OR logic operation on the first synthesis signal and the optical signal, and output a constant TTL level detection signal.

[0012] Further, the shaping circuit includes a retriggerable monostable trigger, the input end of the retriggerable monostable trigger is connected to the enable signal sending end of the laser, and the output end is connected to the input end of the first synthesis circuit;

[0013] The retriggerable monostable trigger is used to detect the signal edge of the laser enable signal. When the signal edge of the enable signal is detected, a TTL level signal with a constant high level time is output, and the reverse signal of the TTL level signal is input into the first synthesis circuit as a shaping signal.

[0014] Furthermore, the retriggerable monostable trigger adopts a SN74LS123DRG4 chip.

[0015] Furthermore, the first synthesis circuit includes a NAND gate chip of model SN74LVC1G00DBVR.

[0016] Furthermore, the first pin of the NAND gate chip U28 is connected to the laser enable signal, the second pin is connected to the shaping signal, the third pin is connected to the digital ground, the fourth pin is output to the second synthesis circuit, and the fifth pin is connected to the DC power supply.

[0017] Furthermore, the second synthesis circuit includes an OR gate chip of model 74LV1G32GV.

[0018] Furthermore, the first pin of the OR gate chip U29 is connected to the amplified optical signal, the second pin is connected to the first synthetic signal, the third pin is connected to the digital ground, the fourth pin outputs the second synthetic signal through the resistor R128, and the fifth pin is connected to the DC power supply.

[0019] Further, the photoelectric detection circuit includes a voltage conversion circuit and an amplifier circuit; the output end of the voltage conversion circuit is connected to the power supply port of the amplifier circuit, the input end of the amplifier circuit is connected to the photodiode, and the output end is connected to the input end of the second synthesis circuit;

[0020] The voltage conversion circuit includes a voltage conversion chip, which is used to perform level conversion on an input first voltage and then output a second voltage, and input the second voltage into the amplifier circuit to provide a reference voltage for the amplifier circuit;

[0021] The amplifying circuit includes a photodiode for receiving an optical signal output by a laser, and also includes an operational amplifier for amplifying the optical signal.

[0022] Furthermore, the model of the voltage conversion chip is LM2662MX / NOPB.

[0023] Furthermore, the operational amplifier has a model of OPA197ID.

[0024] Compared with the prior art, the beneficial effects of the utility model include: receiving and amplifying the optical signal output by the laser through the photoelectric detection circuit to ensure the intensity of the optical signal, providing a basis for real-time monitoring of the working state of the laser; adjusting the laser enable signal through the pulse shaping circuit, outputting a TTL level shaping signal, facilitating subsequent circuit logic operations, performing a non-AND logic operation on the laser enable signal and the shaping signal through the first synthesis circuit and outputting a first synthesis signal, performing an OR operation on the first synthesis signal and the optical signal through the second synthesis circuit, and finally outputting a constant TTL level detection signal to the single-chip microcomputer to detect the working state of the laser.

[0025] This circuit can detect the working status of lasers with different output modes. No matter whether the laser outputs quasi-continuous laser or continuous laser, it can be processed by this circuit into a constant TTL level detection signal. The working status of the laser can be judged according to the detection signal. Therefore, only one IO port resource of the microcontroller is needed to realize abnormal detection under various output states. In addition, this circuit can detect optical signals of any frequency and any duty cycle. The signal has strong applicability and can timely judge whether there is an abnormality in the laser optical path to avoid more serious burning of the laser. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A structural framework diagram of an embodiment of an optical fiber laser optical path detection alarm circuit provided by the utility model;

[0027] Figure 2 A circuit structure diagram of an embodiment of a photoelectric detection circuit provided by the utility model;

[0028] Figure 3 A circuit structure diagram of an embodiment of a shaping circuit provided by the utility model;

[0029] Figure 4A circuit structure diagram of an embodiment of a first synthesis circuit provided by the utility model;

[0030] Figure 5 A circuit structure diagram of an embodiment of a second synthesis circuit provided by the utility model;

[0031] Figure 6 A signal timing diagram of a signal waveform embodiment provided by the present invention. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present application and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0033] In the description of the present application, “plurality” means two or more than two, unless otherwise clearly and specifically defined.

[0034] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0035] The utility model provides an alarm circuit for optical fiber laser light path detection. Figure 1 , Figure 1 The structural framework diagram of the optical path detection alarm circuit for a fiber laser provided in this embodiment includes: a photoelectric detection circuit 101, a pulse shaping circuit 102, a first synthesis circuit 103 and a second synthesis circuit 104; the output end of the photoelectric detection circuit 101 is connected to the input end of the second synthesis circuit 104, the output end of the pulse shaping circuit 102 is connected to the input end of the first synthesis circuit 103, and the output end of the first synthesis circuit 103 is connected to the input end of the second synthesis circuit 104;

[0036] The photoelectric detection circuit 101 is used to receive and amplify the optical signal output by the laser;

[0037] The pulse shaping circuit 102 is used to receive a laser enable signal having a frequency consistent with the optical signal, and output a TTL level shaped signal under the triggering of the laser enable signal;

[0038] The first synthesis circuit 103 is used to perform a non-AND logic operation on the laser enable signal and the shaping signal, and output a first synthesis signal;

[0039] The second synthesis circuit 104 is used to perform an OR logic operation on the first synthesis signal and the optical signal, and output a constant TTL level detection signal.

[0040] The circuit of this embodiment receives and amplifies the optical signal output by the laser through the photoelectric detection circuit to ensure the intensity of the optical signal, providing a basis for real-time monitoring of the working state of the laser; adjusts the laser enable signal through the pulse shaping circuit, outputs a TTL level shaping signal, and facilitates subsequent circuit logic operations; performs a non-AND logic operation on the laser enable signal and the shaping signal through the first synthesis circuit and outputs a first synthesis signal; performs an OR operation on the first synthesis signal and the optical signal through the second synthesis circuit, and finally outputs a constant TTL level detection signal to the single-chip microcomputer to detect the working state of the laser.

[0041] This circuit can detect the working state of lasers with different output modes. No matter whether the laser outputs quasi-continuous laser or continuous laser, it can be processed by this circuit into a constant TTL level detection signal. Based on this detection signal, the working state of the laser can be judged. Therefore, only one IO port resource of the single-chip microcomputer is needed to realize abnormal detection under various output states. In addition, the circuit of the utility model can also detect optical signals of any frequency and any duty cycle (0.8%-99.6%). For example, for optical signals with a large range of cycles between 1Hz-2.5KHz output by the laser, this circuit can detect each optical signal at any frequency, so as to timely judge whether there is an abnormality in the laser optical path and protect the laser.

[0042] As a preferred embodiment, the photoelectric detection circuit includes a voltage conversion circuit and an amplifier circuit; the output end of the voltage conversion circuit is connected to the power supply port of the amplifier circuit, the input end of the amplifier circuit is connected to the photodiode, and the output end is connected to the input end of the second synthesis circuit;

[0043] The voltage conversion circuit includes a voltage conversion chip, which is used to perform level conversion on an input first voltage and then output a second voltage, and input the second voltage into the amplifier circuit to provide a reference voltage for the amplifier circuit;

[0044] The amplifying circuit includes a photodiode for receiving an optical signal output by a laser, and also includes an operational amplifier chip for amplifying the optical signal.

[0045] Specifically, a photodiode is placed at the output end of the laser. When the laser emits a light signal, the light shines on the photodiode to generate a current. The current intensity is proportional to the light intensity of the laser. By measuring the magnitude of the current, the laser signal can be indirectly detected.

[0046] As a preferred embodiment, the model of the voltage conversion chip is LM2662MX / NOPB.

[0047] As a preferred embodiment, the operational amplifier is of model OPA197IDR.

[0048] like Figure 2 As shown, Figure 2 A specific photoelectric detection circuit structure diagram is shown. Pins 1, 5, and 8 of the operational amplifier U19 are suspended, and resistor R80 and capacitor C43 are connected in parallel between pins 2 and 6. Pin 2 is connected to the positive electrode of the photodiode (the photodiode is soldered at -IN_1), and the negative electrode of the photodiode is connected to the digital ground. Pin 3 of U19 is connected to the digital ground, pin 4 is connected to the -5V power supply, pin 7 is connected to the +5V power supply, and pin 6 is the output end, which is connected to the first synthesis circuit through R113. When the laser is working, the photodiode is driven by the operational amplifier U19, the current signal of the diode is amplified, and the amplified light signal PD_1 is output.

[0049] The voltage conversion chip U20 is used to convert the +5V voltage into -5V voltage, providing a reference voltage for the operational amplifier U19. The 1st and 7th pins of U20 are suspended, the 2nd pin is connected to the 4th pin through the capacitor C48, the 3rd and 6th pins are connected to the digital ground, the 8th pin is connected to the +5V power supply, and the 5th pin is the output terminal, outputting a -5V voltage to the 4th pin of U19, i.e. the V- port.

[0050] As a preferred embodiment, the shaping circuit includes a retriggerable monostable trigger, the input end of the retriggerable monostable trigger is connected to the enable signal sending end of the laser, and the output end is connected to the input end of the first synthesis circuit;

[0051] The retriggerable monostable trigger is used to detect the signal edge of the laser enable signal. When the signal edge of the enable signal is detected, a TTL level signal with a constant high level time is output, and the reverse signal of the TTL level signal is input into the first synthesis circuit as a shaping signal.

[0052] As a preferred embodiment, the retriggerable monostable trigger adopts a SN74LS123DRG4 chip.

[0053] like Figure 3 As shown, Figure 3A specific shaping circuit structure diagram is shown. The second pin of the re-triggerable monostable trigger U30 is connected to the laser enable signal sending end through capacitor C87 to receive the laser enable signal. The third and 16th pins are connected to the +5V power supply. The 1st, 8th and 14th pins are connected to the digital ground. The 5th to 7th pins and the 9th to 13th pins are not used. The 15th pin is connected to the +5V power supply through a resistor R125. The 4th pin outputs a TTL level signal / Q with a constant high level time (the / Q signal is the inverse signal of the Q signal at the 13th pin). Among them, the laser enable signal has the same frequency as the optical signal.

[0054] At the frequency of 1-2500Hz, U30 sets the high level time of signal Q to about 54us through C86 (100nF) and R125 (1.5K). The third pin of U30 is high level and the first pin is low level. At this time, U30 is triggered by the rising edge of the second pin, and the second pin is the laser enable signal. Then when the rising edge of the enable signal is detected, the high level of the Q signal is 54us, and the fourth pin inputs the / Q signal into the first synthesis circuit of U28. Here, the high level constant time of the Q signal can be adjusted according to the time interval between the enable signal and the photoelectric detection signal.

[0055] As a preferred embodiment, the first synthesis circuit includes a NAND gate chip of model SN74LVC1G00DBVR.

[0056] like Figure 4 As shown, as a preferred embodiment, the first pin of the NAND gate chip U28 is connected to the laser enable signal, the second pin is connected to the shaping signal, the third pin is connected to the digital ground, the fourth pin outputs the first synthetic signal, and the fifth pin is connected to the DC power supply.

[0057] As a preferred embodiment, the second synthesis circuit includes an OR gate chip of model 74LV1G32GV.

[0058] like Figure 5 As shown, as a preferred embodiment, the first pin of the OR gate chip U29 is connected to the amplified optical signal, the second pin is connected to the first synthetic signal, the third pin is connected to the digital ground, the fourth pin outputs the second synthetic signal through the resistor R128, and the fifth pin is connected to the DC power supply.

[0059] Through the above circuit settings, the laser working state detection is realized when the laser is in different laser output modes. Specifically:

[0060] like Figure 6 As shown, Figure 6The timing diagram of each signal when the circuit is working is shown. When the laser is in quasi-continuous mode output, the laser enable signal EN (frequency is consistent with the optical signal) is input into the retriggerable monostable trigger to obtain a high-level time-constant Q signal, and the shaping circuit outputs the reverse signal / Q of the Q signal; the first synthesis circuit synthesizes the / Q signal and the laser enable signal EN into a signal CS through a NAND gate chip (SN74LVC1G00DBVR), and the second synthesis circuit synthesizes the CS signal and the optical signal PD_1 amplified by the photoelectric detection circuit into PD_SAM. When the PD_1 signal is normal, the PD_SAM signal is always high. Figure 6 The red box in the figure shows the situation when the PD_1 optical signal is abnormal. At this time, the PD_SAM signal will become a low level, and the signal is transmitted to the microcontroller to issue a laser alarm.

[0061] When the laser is in continuous mode output, the signal received by the photodetection diode is a continuous signal; at this time, the synthesized signal after conversion by the circuit is still at a high level.

[0062] Outputting the synthesized signal to the single-chip microcomputer can enable one I / O port of the single-chip microcomputer to read the photoelectric detection signal under two light emission modes and make a judgment, which effectively protects the laser and saves the resources of the single-chip microcomputer.

[0063] This circuit can detect the working status of lasers with different output modes. No matter whether the laser outputs quasi-continuous laser or continuous laser, it can be processed by this circuit into a constant TTL level detection signal. The working status of the laser can be judged according to the detection signal. Therefore, only one IO port resource of the microcontroller is needed to realize abnormal detection under various output states. In addition, this circuit can detect optical signals of any frequency and any duty cycle. The signal has strong applicability and can timely judge whether there is an abnormality in the laser optical path to avoid more serious burning of the laser.

[0064] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with the technical field within the technical scope disclosed in the present invention should be included in the protection scope of the present invention.

Claims

1. A fiber laser optical path detection alarm circuit, characterized in that: include: A photoelectric detection circuit, a pulse shaping circuit, a first synthesis circuit and a second synthesis circuit; The output end of the photoelectric detection circuit is connected to the input end of the second synthesis circuit, the output end of the pulse shaping circuit is connected to the input end of the first synthesis circuit, and the output end of the first synthesis circuit is connected to the input end of the second synthesis circuit; The photoelectric detection circuit is used to receive and amplify the optical signal output by the laser; The pulse shaping circuit is used to receive a laser enable signal having a frequency consistent with the optical signal, and output a TTL level shaped signal under the triggering of the laser enable signal; The first synthesis circuit is used to perform a non-AND logic operation on the laser enable signal and the shaping signal, and output a first synthesis signal; The second synthesis circuit is used to perform an OR logic operation on the first synthesis signal and the optical signal, and output a constant TTL level detection signal.

2. The optical path detection alarm circuit for a fiber laser according to claim 1, characterized in that: The shaping circuit comprises a retriggerable monostable trigger, the input end of the retriggerable monostable trigger is connected to the enable signal sending end of the laser, and the output end is connected to the input end of the first synthesis circuit; The retriggerable monostable trigger is used to detect the signal edge of the laser enable signal. When the signal edge of the enable signal is detected, a TTL level signal with a constant high level time is output, and the reverse signal of the TTL level signal is input into the first synthesis circuit as a shaping signal.

3. The optical path detection alarm circuit for a fiber laser according to claim 2, characterized in that: The retriggerable monostable trigger adopts the SN74LS123DRG4 chip.

4. The optical path detection alarm circuit for a fiber laser according to claim 1, characterized in that: The first synthesis circuit includes a NAND gate chip of model SN74LVC1G00DBVR.

5. The optical path detection alarm circuit for fiber laser according to claim 4, characterized in that: The first pin of the NAND gate chip U28 is connected to the laser enable signal, the second pin is connected to the shaping signal, the third pin is connected to the digital ground, the fourth pin is output to the second synthesis circuit, and the fifth pin is connected to the DC power supply.

6. The optical path detection alarm circuit for a fiber laser according to claim 1, characterized in that: The second synthesis circuit includes an OR gate chip of model 74LV1G32GV.

7. The optical path detection alarm circuit for a fiber laser according to claim 6, characterized in that: The first pin of the OR gate chip U29 is connected to the amplified optical signal, the second pin is connected to the first synthetic signal, the third pin is connected to the digital ground, the fourth pin outputs the second synthetic signal through the resistor R128, and the fifth pin is connected to the DC power supply.

8. The optical path detection alarm circuit for a fiber laser according to claim 1, characterized in that: The photoelectric detection circuit includes a voltage conversion circuit and an amplifier circuit; the output end of the voltage conversion circuit is connected to the power supply port of the amplifier circuit, the input end of the amplifier circuit is connected to the photodiode, and the output end is connected to the input end of the second synthesis circuit; The voltage conversion circuit includes a voltage conversion chip, which is used to perform level conversion on an input first voltage and then output a second voltage, and input the second voltage into the amplifier circuit to provide a reference voltage for the amplifier circuit; The amplifying circuit includes a photodiode for receiving an optical signal output by a laser, and also includes an operational amplifier for amplifying the optical signal.

9. The optical path detection alarm circuit for fiber laser according to claim 8, characterized in that: The model of the voltage conversion chip is LM2662MX / NOPB.

10. The optical path detection alarm circuit for a fiber laser according to claim 8, characterized in that: The model of the operational amplifier is OPA197ID.

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