Frequency-modulated continuous-wave laser nonlinear correction compensation device and lidar apparatus

Abstract

The application belongs to the technical field of laser radar, and particularly relates to a frequency-modulated continuous wave laser nonlinear correction compensation device and a laser radar equipment. The frequency-modulated continuous wave laser nonlinear correction compensation device comprises a laser, a laser driver circuit, an optoelectronic conversion circuit, a frequency multiplication circuit, a signal comparison circuit and a modulation circuit. The output current of the laser driver circuit is controlled through the optoelectronic conversion circuit, the frequency multiplication circuit, the signal comparison circuit and the modulation circuit, so that the driving current of the laser is negatively fed back and adjusted, the linearity of the output frequency of the laser is improved, the ranging device realizes ranging and speed measurement according to the negatively fed back and adjusted light signal, and the ranging precision and accuracy are improved.

Description

Technical Field

[0001] This invention belongs to the field of lidar technology, and particularly relates to a frequency-modulated continuous wave laser nonlinear correction and compensation device and lidar equipment. Background Technology

[0002] Frequency-modulated continuous wave (FM-CW) laser ranging can achieve high-precision ranging measurements and has a very promising future in lidar ranging and velocity measurement. Typical FM-CW lasers use linear frequency modulation, such as triangular wave frequency modulation. However, since lasers are nonlinear devices, their frequency changes exhibit a nonlinear response under linear drive signals, making them difficult to use for ranging. Therefore, the industry commonly uses pre-calibration signals to drive lasers. These pre-calibration signals are nonlinear drive signals obtained through multiple experiments based on linear drive signals (such as triangular wave signals), enabling the frequency of the laser's output optical signal to approach linearity.

[0003] While using a pre-calibration signal can greatly improve the nonlinear output of a laser, the pre-calibration signal is a fixed modulation signal obtained through multiple experiments. On the one hand, the fitting method and the number of times have a great impact on the accuracy. On the other hand, the pre-calibration signal cannot be changed in real time to adapt to different environments. For example, when the ambient temperature changes, the response characteristics of the laser and the circuit will change, which will lead to a deterioration in the linearity of the laser output optical signal. Moreover, the same pre-calibration signal cannot adapt to the differences between different lasers. However, it is obviously impractical to customize a pre-calibration signal for each laser individually. Summary of the Invention

[0004] The purpose of this invention is to provide a frequency-modulated continuous wave laser nonlinear correction and compensation device, which aims to adaptively adjust the magnitude of the laser's driving current, thereby improving the linearity of the laser output and enhancing the accuracy and precision of laser ranging.

[0005] A first aspect of this invention provides a frequency-modulated continuous wave laser nonlinear correction and compensation device, comprising: A laser that emits an optical signal when triggered by a driving current; A driving circuit is used to output a driving current of a corresponding magnitude to the laser when triggered by a triangular wave modulation signal; A photoelectric conversion circuit is used to perform photoelectric conversion on the optical signal emitted by the laser and output a first electrical signal whose frequency is positively correlated with the frequency of the optical signal. A frequency multiplier circuit is used to multiply the frequency of the electrical signal output by the photoelectric conversion circuit to output a second electrical signal, the frequency of which is greater than the frequency of the first electrical signal. A signal comparison circuit is used to compare the second electrical signal output by the frequency multiplier circuit with a preset reference electrical signal, and output a scaling signal whose magnitude is negatively correlated with the frequency magnitude of the second electrical signal. The modulation circuit is used to modulate the pre-correction signal according to the scaling signal output by the signal comparison circuit, and output a triangular wave modulation signal to the laser driving circuit to perform negative feedback adjustment on the driving current output by the laser driving circuit, so as to adjust the linearity of the optical signal output by the laser.

[0006] In one possible implementation, the frequency multiplier circuit includes: The circuit comprises a first frequency and phase detector, a first loop filter, and a voltage-controlled oscillator (VCO). The input of the first frequency and phase detector is connected to the output of the photoelectric conversion circuit. The output of the first frequency and phase detector is connected to the input of the first loop filter. The output of the first loop filter is connected to the input of the VCO. The output of the VCO is connected to the inputs of the first frequency and phase detector and the signal comparison circuit.

[0007] In one possible implementation, the modulation circuit includes: A pre-correction signal generation circuit is used to output the pre-correction signal; The multiplication circuit is used to multiply the pre-correction signal output by the pre-correction signal generation circuit and the scaling signal output by the signal comparison circuit, and output the triangular wave modulation signal to the laser driving circuit.

[0008] In one possible implementation, the modulation circuit further includes: A filter circuit is connected to the signal comparison circuit and the multiplication circuit respectively, and the filter circuit is used to filter the scaling signal.

[0009] In one possible implementation, the photoelectric conversion circuit includes: A first beam splitter for beam splitting output, wherein the first beam splitter is used to receive the optical signal emitted by the laser and split it out through two output terminals; A delay fiber for signal delay output, wherein the first end of the delay fiber is connected to the first output end of the first beam splitter; A balanced detector for photoelectric conversion, wherein the first input terminal of the balanced detector is connected to the second output terminal of the first beam splitter, the second input terminal of the balanced detector is connected to the second end of the delay fiber, and the output terminal of the balanced detector constitutes the signal output terminal of the photoelectric conversion circuit.

[0010] In one possible implementation, the photoelectric conversion circuit further includes: An optical mixer for frequency mixing, wherein the first input terminal of the optical mixer is connected to the second output terminal of the first beam splitter, the second input terminal of the optical mixer is connected to the second end of the delay fiber, the output terminal of the optical mixer is connected to the input terminal of the balanced detector, and the output terminal of the balanced detector constitutes the signal output terminal of the photoelectric conversion circuit.

[0011] In one possible implementation, the frequency-modulated continuous wave laser nonlinear correction and compensation device further includes: A second beam splitter is connected to the laser and the photoelectric conversion circuit respectively. The second beam splitter splits the light signal emitted by the laser and outputs it to the photoelectric conversion circuit and the ranging device respectively.

[0012] In one possible implementation, the signal comparison circuit includes: Active crystal oscillator; A second frequency and phase detector is connected to the frequency multiplier circuit, the active crystal oscillator, and the modulation circuit, respectively.

[0013] Secondly, this application provides a lidar device, including the frequency-modulated continuous wave laser nonlinear correction and compensation device described in the first aspect or any optional embodiment of the first aspect.

[0014] In one possible implementation, the lidar device further includes a ranging device, which is connected to the frequency-modulated continuous wave laser nonlinear correction and compensation device.

[0015] The beneficial effects of this invention compared to existing technologies are as follows: The aforementioned frequency-modulated continuous wave laser nonlinear correction and compensation device uses a photoelectric conversion circuit, a signal comparison circuit, a frequency multiplication circuit, and a modulation circuit to control the output current of the laser drive circuit, thereby achieving negative feedback adjustment of the laser drive current to adjust the linearity of the frequency of the laser output optical signal, resulting in a more optimized linearity. This enables the ranging device to perform ranging and velocity measurements based on the negative feedback-adjusted optical signal, thus improving the accuracy and precision of laser ranging. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of a first structure of the frequency-modulated continuous wave laser nonlinear correction and compensation device provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of a second structure of the frequency-modulated continuous wave laser nonlinear correction and compensation device provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of a third structure of the frequency-modulated continuous wave laser nonlinear correction and compensation device provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of the fourth structure of the frequency-modulated continuous wave laser nonlinear correction and compensation device provided in the embodiments of the present invention; Figure 5 This is a schematic diagram of the fifth structure of the frequency-modulated continuous wave laser nonlinear correction and compensation device provided in the embodiments of the present invention; Figure 6 This is a schematic diagram of the sixth structure of the frequency-modulated continuous wave laser nonlinear correction and compensation device provided in the embodiments of the present invention; Figure 7 This is a schematic diagram of the seventh structure of the frequency-modulated continuous wave laser nonlinear correction and compensation device provided in the embodiments of the present invention; Figure 8 This is a schematic diagram of the eighth structure of the frequency-modulated continuous wave laser nonlinear correction and compensation device provided in the embodiments of the present invention; Figure 9 This is a schematic diagram of the structure of a lidar device provided in an embodiment of the present invention. Detailed Implementation

[0017] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present invention and are not intended to limit the present invention.

[0018] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0019] A first aspect of the present invention provides a frequency-modulated continuous wave laser nonlinear correction and compensation device 100.

[0020] like Figure 1 As shown, in this embodiment, the frequency-modulated continuous wave laser nonlinear correction and compensation device 100 includes: Laser 10, which is triggered by driving current to emit optical signals; The laser driving circuit 20 is used to output a driving current of a corresponding magnitude to the laser 10 when triggered by a triangular wave modulation signal. The photoelectric conversion circuit 30 is used to perform photoelectric conversion on the optical signal emitted by the laser 10 and output a first electrical signal whose frequency is positively correlated with the frequency of the optical signal. The frequency multiplier circuit 40 is used to multiply the frequency of the first electrical signal output by the photoelectric conversion circuit 30 and output a second electrical signal, the frequency of which is greater than the frequency of the first electrical signal. The signal comparison circuit 50 is used to compare the second electrical signal output by the frequency multiplier circuit 40 with the preset reference electrical signal, and output a scaling signal whose magnitude is negatively correlated with the frequency magnitude of the second electrical signal. The modulation circuit 60 is used to modulate the pre-correction signal according to the scaling signal output by the signal comparison circuit 50, and output a triangular wave modulation signal to the laser driver circuit 20 to perform negative feedback adjustment on the drive current output by the laser driver circuit 20, so as to adjust the linearity of the frequency of the optical signal output by the laser.

[0021] In this embodiment, after the frequency-modulated continuous wave laser nonlinear correction and compensation device 100 is initially powered on, it quickly enters an initial steady state. The laser drive circuit 20 outputs an initial drive current to drive the laser 10 to operate, and the laser 10 emits an optical signal. The optical signal is input to the photoelectric conversion circuit 30 through an optical fiber, where it undergoes a positive proportional photoelectric conversion, meaning that the frequency of the first electrical signal output by the conversion is positively correlated with the frequency of the optical signal emitted by the laser 10. Then, the first electrical signal is frequency-multiplied by the frequency multiplier circuit 40 to obtain a frequency-amplified second electrical signal. For example, if the frequency of the first electrical signal obtained after photoelectric conversion is 20MHz, after processing by the frequency multiplier circuit 40, a second electrical signal of 100MHz is obtained.

[0022] Next, the second electrical signal is output to the signal comparison circuit 50 for signal comparison. The preset reference electrical signal in the signal comparison circuit 50 is a fixed-frequency electrical signal. The frequency of the preset reference signal corresponds to the beat frequency of the ideal linear frequency modulated light after a fixed delay, which can be determined by the length of the time-delay fiber. The signal comparison circuit 50 compares the second electrical signal with the reference signal and outputs a scaling signal that is negatively correlated with the frequency of the second electrical signal. The modulation circuit 60 then multiplies this scaling signal with a pre-correction signal to perform real-time feedback adjustment of the pre-correction signal. This results in the triangular wave modulation signal received by the laser driver circuit 20 being a negatively feedback-adjusted triangular wave modulation signal, and outputs a corresponding negatively feedback-adjusted drive current to the laser 10, making the optical signal output by the laser 10 more linear.

[0023] Meanwhile, when faced with different lasers 10, or when the same laser 10 exhibits different nonlinear responses at different frequencies under different environments, the scaling factor signal is adaptively calculated through negative feedback adjustment, thereby adjusting the size of the laser drive circuit 20 in real time to make the output optical signal of the laser more linear. Thus, the ranging device 200 uses the modulated optical signal to achieve laser ranging and velocity measurement, improving the accuracy and precision of laser ranging.

[0024] The preset reference electrical signal can be generated internally by the signal comparison circuit 50 or obtained from an external corresponding signal source; the specific method of acquisition is not limited.

[0025] The laser 10 can be of different types, such as FP (Fabry-perot) laser 10, DFB (Distributed Feedback Laser) laser 10, etc. Optionally, the laser 10 is a DFB laser 10. The DFB laser 10 can maintain single-mode characteristics even when modulated at high speed and can be used for long-distance transmission.

[0026] The laser driving circuit 20 can use a corresponding current source circuit, and the specific structure is not limited.

[0027] The photoelectric conversion circuit 30 can be constructed using a corresponding optical path structure, such as a balanced detector 33, an optical mixer, etc., and the specific structure is not limited.

[0028] In one example, such as Figure 2 As shown, optionally, the photoelectric conversion circuit 30 may include: The first beam splitter 31 is used to receive the optical signal output by the laser 10 and split it through two output terminals for output. The delay fiber 32 is used for signal delay output, and the first end of the delay fiber 32 is connected to the first output end of the first beam splitter 31. The balanced detector 33 is used for photoelectric conversion. The first input terminal of the balanced detector 33 is connected to the second output terminal of the first beam splitter 31. The second input terminal of the balanced detector 33 is connected to the second end of the delay fiber 32. The output terminal of the balanced detector 33 constitutes the signal output terminal of the photoelectric conversion circuit 30.

[0029] In this embodiment, the optical signal output from the laser 10, after passing through the first beam splitter 31, is delayed via the delay fiber 32 and input to the first input terminal of the balanced detector 33, while the other is directly input to the second input terminal of the balanced detector 33. The balanced detector 33 converts the two input optical signals into coherent light and outputs a differential current signal to the frequency multiplier circuit 40. The output current of the balanced detector 33 changes with the frequency of the laser 10, meaning its output current has a corresponding optical curve to the frequency of the laser 10. The balanced detector 33 is an unbalanced Mach-Zehnder interferometer.

[0030] In another example, based on Figure 2 ,like Figure 3 As shown, optionally, the photoelectric conversion circuit 30 may further include: The optical mixer 34 is used for frequency mixing. The first input terminal of the optical mixer 34 is connected to the second output terminal of the first beam splitter 31. The second input terminal of the optical mixer 34 is connected to the second end of the delay fiber 32. The output terminal of the optical mixer 34 is connected to the input terminal of the balanced detector 33. The output terminal of the balanced detector 33 constitutes the signal output terminal of the photoelectric conversion circuit 30.

[0031] In this embodiment, the optical mixer 34 is used to superimpose two optical signals to generate two beat frequency signals with a phase difference of 180 degrees. The low-frequency component of the beat frequency signal is converted into an electrical signal by the balanced detector 33 to suppress common-mode noise.

[0032] In this embodiment, the frequency multiplier circuit 40 can be a phase-locked loop (PLL) circuit or a delay-locked loop (DLL).

[0033] For example, such as Figure 4 As shown, taking a PLL circuit as an example, the frequency multiplier circuit 40 may include a first frequency and phase detector 41, a first loop filter 42, and a voltage-controlled oscillator 43.

[0034] The input terminal of the first frequency and phase detector 41 is connected to the output of the photoelectric conversion circuit 30. The output terminal of the first frequency and phase detector 41 is connected to the input terminal of the first loop filter 42. The output terminal of the first loop filter 42 is connected to the input terminal of the voltage-controlled oscillator (VCO) 43. The output terminal of the voltage-controlled oscillator 43 is connected to the input terminals of the first frequency and phase detector 41 and the signal comparison circuit 50.

[0035] Using a PLL circuit as the frequency multiplier circuit 40 provides a more flexible adjustment range. For example, the frequency of the first electrical signal can be multiplied by 3 to 5 times. A 20MHz first electrical signal can be multiplied to 60MHz to 100MHz.

[0036] The signal comparison circuit 50 can employ a corresponding frequency comparison circuit and signal generation circuit, for example, including a second frequency and phase detector 52, a frequency detector, etc. Optionally, such as... Figure 5 As shown, the signal comparison circuit 50 may include: There is a reference signal generation circuit 51; A second frequency and phase detector 52 is connected to the frequency multiplication circuit 40, the reference signal generation circuit 51, and the modulation circuit 60, respectively.

[0037] Specifically, the reference signal generation circuit 51 can be an active crystal oscillator or a PLL circuit, etc.

[0038] For example, taking an active crystal oscillator as an example, the crystal frequency is calculated as follows: Assuming the crystal oscillator frequency is Fc, the delay duration of the delay fiber is t, the frequency modulation bandwidth is B, and the frequency modulation period is T, then we have B = (Fc*T) / 2t.

[0039] Under ideal linearity conditions, the frequency of the beat frequency signal (i.e., optical signal) output by the laser remains constant within the modulation period, which is the crystal oscillator frequency. Therefore, the frequency difference between the beat frequency signal and the crystal oscillator signal (i.e., the preset reference signal) reflects the deviation between the frequency modulation linearity and the ideal linearity of the laser.

[0040] In this embodiment, the reference signal generation circuit 51 generates a preset reference electrical signal at a preset frequency, and the second frequency and phase detector 52 generates a scaling signal that is proportional to the frequency difference between the preset reference electrical signal and the second electrical signal output by the frequency multiplier circuit 40. The second frequency and phase detector 52 corrects the difference between the two input signals in the loop to achieve frequency locking.

[0041] In one example, such as Figure 6 As shown, the modulation circuit 60 may include: The pre-calibration signal generation circuit 61 is used to output the pre-calibration signal; The multiplication circuit 62 is used to multiply the pre-correction signal output by the pre-correction signal generation circuit 61 and the scaling signal output by the signal comparison circuit 50, and output a triangular wave modulated signal to the laser drive circuit.

[0042] The pre-correction signal generation circuit 61 can be a corresponding signal source circuit. The multiplication circuit 62 can be a multiplier, transistor, or other structure, and the specific structure is not limited.

[0043] Optional, such as Figure 7 As shown, the modulation circuit 60 also includes: The filter circuit 63 is connected to the signal comparison circuit 50 and the multiplication circuit 62 respectively. The filter circuit 63 is used to filter the scaling signal to filter out the noise generated therein, thereby outputting a filtered scaling signal to the multiplication circuit 62. This ensures that the multiplication circuit 62 obtains an accurate scaling signal, reduces circuit oscillation, and improves the accuracy of feedback regulation.

[0044] For example, the filter circuit 63 can adopt different filter structures. For instance, the filter circuit 63 can be a passive filter or an active filter.

[0045] It is worth noting that the filtering bandwidth setting of the filtering circuit 63 is related to the second frequency and phase detector 52 in the signal comparison circuit 50. If the filtering bandwidth is set too small, the filtering circuit 63 will pass low frequencies and block high frequencies, meaning only very low-frequency electrical signals can pass through, resulting in slow adjustment capability. Therefore, in this embodiment, the frequency of the first electrical signal is amplified by the frequency multiplier circuit 40, allowing the second frequency and phase detector 52 in the signal comparison circuit 50, which receives the second electrical signal, to be set to a larger frequency. This allows for a larger filtering bandwidth, enabling the filtering circuit 63 to adjust the optical signals at more points within a fixed time, greatly improving the negative feedback adjustment speed.

[0046] In this embodiment, the frequency of the first electrical signal is amplified by setting a frequency multiplier circuit 40. In this embodiment, the output current of the laser drive circuit 20 is controlled by using a photoelectric conversion circuit 30, a frequency multiplication circuit 40, a signal comparison circuit 50, and a modulation circuit 60, thereby achieving negative feedback adjustment of the drive current of the laser 10 and linearizing the output frequency of the laser 10. This ensures that the ranging device 200 can perform ranging and speed measurement based on the light signal after negative feedback adjustment, and improves the ranging accuracy and precision.

[0047] In one embodiment, such as Figure 8 As shown, optionally, the frequency-modulated continuous wave laser nonlinear correction and compensation device 100 further includes: The second beam splitter 70 is connected to the laser 10 and the photoelectric conversion circuit 30 respectively. The second beam splitter 70 splits the linear frequency modulated light signal currently emitted by the laser 10 and outputs it to the photoelectric conversion circuit 30 and the ranging device 200 respectively.

[0048] In this embodiment, the ranging device 200 acquires the light signal output by the laser 10 through the second beam splitter 70, and determines the distance and speed of the object to be measured based on the light signal adjusted by negative feedback, thereby achieving accurate ranging. For example, the light signal output by the laser 10 will hit the surface of the object to be measured, generating a reflected light signal. The ranging device 200 acquires the reflected light signal reflected by the object to be measured through the laser receiving component, and determines the distance and speed of the object to be measured based on the frequency difference between the emission and reception of the light signal, thereby realizing the lidar ranging function. The type of the ranging device 200 is not limited, and it can be composed of components such as optical receiving elements, photoelectric converters, power amplifiers, and controllers.

[0049] The optical paths between the laser 10, the first beam splitter 31, the second beam splitter 70, the delay fiber 32, the optical mixer 34, and the balanced detector 33 are connected by optical fibers.

[0050] Based on the above-described frequency-modulated continuous wave laser nonlinear correction and compensation device 100, this application also provides a lidar device, which includes the frequency-modulated continuous wave laser nonlinear correction and compensation device 100 as described in any of the above embodiments.

[0051] In this embodiment, the lidar device uses a frequency-modulated continuous wave laser nonlinear correction and compensation device 100 to achieve negative feedback adjustment of the driving current of the laser 10, linearizing the output frequency of the laser 10, so that the ranging device 200 can perform ranging and speed measurement based on the light signal after negative feedback adjustment, and improve the ranging accuracy and precision.

[0052] The ranging device 200 can be installed inside the lidar equipment or separately; optionally, for example... Figure 9 As shown, the lidar device also includes a ranging device 200, which is connected to the frequency-modulated continuous wave laser nonlinear correction and compensation device 100. The ranging device 200 performs laser ranging and velocity measurement based on the optical signal output by the frequency-modulated continuous wave laser nonlinear correction and compensation device 100 to achieve accurate ranging.

[0053] The above-described embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be included within the protection scope of the present invention.

Claims

1. A frequency-modulated continuous wave laser nonlinear correction and compensation device, characterized in that, include: A laser that emits an optical signal when triggered by a driving current; A driving circuit is used to output a driving current of a corresponding magnitude to the laser when triggered by a triangular wave modulation signal; A photoelectric conversion circuit is used to perform photoelectric conversion on the optical signal emitted by the laser and output a first electrical signal whose frequency is positively correlated with the frequency of the optical signal. A frequency multiplier circuit is used to multiply the frequency of the electrical signal output by the photoelectric conversion circuit to output a second electrical signal, the frequency of which is greater than the frequency of the first electrical signal. A signal comparison circuit is used to compare the second electrical signal output by the frequency multiplier circuit with a preset reference electrical signal, and output a scaling signal whose magnitude is negatively correlated with the frequency magnitude of the second electrical signal; wherein, the preset reference electrical signal is a fixed frequency electrical signal, and the frequency magnitude of the preset reference electrical signal corresponds to the beat frequency of an ideal linear frequency modulated light after a fixed delay. The modulation circuit is used to multiply the scaling signal output by the signal comparison circuit with the pre-correction signal to perform real-time feedback adjustment of the pre-correction signal, and output a triangular wave modulation signal to the driving circuit to perform negative feedback adjustment of the driving current output by the driving circuit, so as to adjust the linearity of the frequency of the laser output optical signal.

2. The frequency-modulated continuous wave laser nonlinear correction and compensation device according to claim 1, characterized in that, The frequency multiplier circuit includes: The circuit comprises a first frequency and phase detector, a first loop filter, and a voltage-controlled oscillator (VCO). The input of the first frequency and phase detector is connected to the output of the photoelectric conversion circuit. The output of the first frequency and phase detector is connected to the input of the first loop filter. The output of the first loop filter is connected to the input of the VCO. The output of the VCO is connected to the inputs of the first frequency and phase detector and the signal comparison circuit.

3. The frequency-modulated continuous wave laser nonlinear correction and compensation device according to claim 1, characterized in that, The modulation circuit includes: A pre-correction signal generation circuit is used to output the pre-correction signal; The multiplication circuit is used to multiply the pre-correction signal output by the pre-correction signal generation circuit and the scaling signal output by the signal comparison circuit, and output the triangular wave modulation signal to the driving circuit.

4. The frequency-modulated continuous wave laser nonlinear correction and compensation device according to claim 3, characterized in that, The modulation circuit further includes: A filter circuit is connected to the signal comparison circuit and the multiplication circuit respectively, and the filter circuit is used to filter the scaling signal.

5. The frequency-modulated continuous wave laser nonlinear correction and compensation device according to claim 1, characterized in that, The photoelectric conversion circuit includes: A first beam splitter for beam splitting output, wherein the first beam splitter is used to receive the optical signal emitted by the laser and split it out through two output terminals; A delay fiber for signal delay output, wherein the first end of the delay fiber is connected to the first output end of the first beam splitter; A balanced detector for photoelectric conversion, wherein the first input terminal of the balanced detector is connected to the second output terminal of the first beam splitter, the second input terminal of the balanced detector is connected to the second end of the delay fiber, and the output terminal of the balanced detector constitutes the signal output terminal of the photoelectric conversion circuit.

6. The frequency-modulated continuous wave laser nonlinear correction and compensation device according to claim 1, characterized in that, The photoelectric conversion circuit includes: A first beam splitter for beam splitting output, wherein the first beam splitter is used to receive the optical signal emitted by the laser and split it out through two output terminals; A delay fiber for signal delay output, wherein the first end of the delay fiber is connected to the first output end of the first beam splitter; Balanced detectors used for photoelectric conversion; An optical mixer for frequency mixing, wherein the first input terminal of the optical mixer is connected to the second output terminal of the first beam splitter, the second input terminal of the optical mixer is connected to the second end of the delay fiber, the output terminal of the optical mixer is connected to the input terminal of the balanced detector, and the output terminal of the balanced detector constitutes the signal output terminal of the photoelectric conversion circuit.

7. The frequency-modulated continuous wave laser nonlinear correction and compensation device according to claim 1, characterized in that, The frequency-modulated continuous wave laser nonlinear correction and compensation device further includes: A second beam splitter is connected to the laser and the photoelectric conversion circuit respectively. The second beam splitter splits the light signal emitted by the laser and outputs it to the photoelectric conversion circuit and the ranging device respectively.

8. The frequency-modulated continuous wave laser nonlinear correction and compensation device according to claim 1, characterized in that, The signal comparison circuit includes: Active crystal oscillator; A second frequency and phase detector is connected to the frequency multiplier circuit, the active crystal oscillator, and the modulation circuit, respectively.

9. A lidar device, characterized in that, Includes the frequency-modulated continuous wave laser nonlinear correction and compensation device as described in any one of claims 1 to 8.

10. The lidar device according to claim 9, characterized in that, The lidar device also includes a ranging device, which is connected to the frequency-modulated continuous wave laser nonlinear correction and compensation device.

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