CN117724071A

CN117724071A - Laser radar system

Info

Publication number: CN117724071A
Application number: CN202311786310.6A
Authority: CN
Inventors: 周广柱; 朱瑞; 丁越峰; 张轲
Original assignee: Saili Technology Suzhou Co ltd
Current assignee: Saili Technology Suzhou Co ltd
Priority date: 2023-12-22
Filing date: 2023-12-22
Publication date: 2024-03-19

Abstract

The present invention provides a lidar system comprising: a light source generating module for providing a laser signal; the optical path conversion module is integrated on the silicon optical chip and is used for generating and transmitting a laser emission signal and converting a received returned laser echo signal into beat current; the signal processing module processes the beat current to obtain radar detection information of the detected object; the control module supplies power to and controls the light source generation module, the light path conversion module and the signal processing module. The optical path conversion module with the largest volume and higher cost is integrated on the silicon optical chip, so that the volume of the laser radar system is effectively reduced, and the manufacturing cost can be reduced to a certain extent; meanwhile, after the optical path conversion module is integrated on the silicon optical chip, the precision of each device is higher, and the device is not easy to wear, so that the reliability of the laser radar system can be effectively improved, and the problems of large volume, high cost and lower reliability of the existing laser radar system are solved.

Description

Laser radar system

Technical Field

The invention relates to the technical field of laser radars, in particular to a laser radar system.

Background

The laser beam has the characteristics of high directivity, strong coherence and good monochromaticity, so that the laser radar can realize long-distance high-resolution detection, and therefore, the laser radar is widely applied to scenes such as military, remote sensing, intelligent driving and the like.

Existing lidars generally construct an ambient 3D point cloud by actively scanning a laser beam, i.e. by reflected signals at different spatial locations. In order to realize active scanning of laser beams, the existing laser radar generally performs laser radar scanning based on mechanical rotation type or semi-solid type (such as a rotating mirror and a vibrating mirror), and the scheme not only ensures that the laser radar system has large volume, large size and high manufacturing and maintenance cost, but also has lower reliability due to factors such as precision and abrasion of mechanical parts.

In addition, since the signal emitted by the existing laser radar is generally linearly polarized light, when the emitted signal (linearly polarized light) is reflected and scattered by the target object, the echo signal contains two orthogonally polarized lights, and only the echo signal with the same polarization as the local oscillation light can generate effective output after mixing, so that most of the laser radar systems currently only receive the information of one polarized echo signal or only process the echo signal with one polarized signal, so that the amplitude of the coherent received signal is lower, and the maximum detection distance of the laser radar system is limited.

Disclosure of Invention

The invention aims to provide a laser radar system which at least solves the problems of large volume, high cost and low reliability of the existing laser radar system.

In order to solve the above technical problems, the present invention provides a lidar system, comprising:

the light source generation module is used for providing a laser signal;

the optical path conversion module is integrated on a silicon optical chip and is used for converting a laser signal to generate and send a laser emission signal, receiving a returned laser echo signal and converting the laser echo signal into beat current;

the signal processing module is used for processing the beat frequency current to obtain radar detection information of the detected object;

the control module is used for supplying power to the light source generation module, the light path conversion module and the signal processing module and controlling the light source generation module, the light path conversion module and the signal processing module.

Optionally, in the laser radar system, the light source generating module includes a laser and an optical amplifier; the laser is used for providing a laser beam with a wavelength adjustment range of more than 100 nm; the optical amplifier is used for amplifying the energy of the laser beam emitted by the laser to provide a laser signal.

Optionally, in the lidar system, the optical path conversion module includes a coupling unit, a beam splitting unit, a calibration unit, a signal transceiver unit, and a beam combining detection unit; the coupling unit is used for receiving the laser signal and coupling the laser signal; the beam splitting unit is used for splitting the coupled laser signals into at least three paths, one path is input to the calibration unit, the rest is input to the beam combining detection unit as local oscillation light, and the rest is input to the signal receiving and transmitting unit; the calibration unit is used for calibrating the frequency modulation nonlinearity of the laser signal; the signal receiving and transmitting unit is used for sending laser emission signals and receiving returned laser echo signals; the beam combination detection unit is used for processing the local oscillation light and the laser echo signal to obtain beat frequency current.

Optionally, in the lidar system, the beam splitting unit includes a first-stage beam splitter, a second-stage beam splitter, and a third-stage beam splitter; the first-order beam splitter is connected with the optical path of the coupling unit so as to split the coupled laser signals into two paths; the second-stage beam splitter is connected with the first-stage beam splitter in a light path so as to divide one path of laser sub-signal split by the first-stage beam splitter into two paths, wherein one path of the laser sub-signal is directly connected with the light path of the calibration unit, and the other path of the laser sub-signal is connected with the light path of the calibration unit through an optical waveguide delay line; the three-stage beam splitter is connected with the optical path of the first-stage beam splitter so as to divide the other path of laser sub-signals split by the first-stage beam splitter into two paths, wherein one path of laser sub-signals is used as local oscillation light to be input to the beam combination detection unit, and the other path of laser sub-signals are input to the signal receiving and transmitting unit.

Optionally, in the lidar system, the three-stage optical splitter includes a plurality of sub-optical splitters connected in a hierarchy, each sub-optical splitter splits an optical signal received from a previous hierarchy into two paths, one path is used as local oscillation light and input to the beam combination detection unit, and the other path is used as local oscillation light and input to the signal transceiver unit.

Optionally, in the laser radar system, the signal transceiver unit includes an auto-collimation transmitting module and a receiving module; the self-collimation transmitting module comprises a beam splitter, a phase modulator and a transmitting antenna, so as to modulate a laser signal to obtain a laser transmitting signal and transmit the laser transmitting signal; the receiving module is used for receiving the returned laser echo signals and dividing the laser echo signals into x polarized light and y polarized light.

Optionally, in the laser radar system, the receiving module includes a first optical phased array and a second optical phased array; the first optical phased array is used for receiving the x-polarized light and inputting the received x-polarized light to the beam combination detection unit; the second optical phased array is used for receiving y polarized light and inputting the received y polarized light to the beam combination detection unit through the polarization rotator and the phase tuner.

Optionally, in the lidar system, the receiving module includes a grating antenna and a polarizing beam splitter; the grating antenna is used for receiving the laser echo signals; the polarization beam splitter is used for dividing the laser echo signal into x polarized light and y polarized light, and the x polarized light is directly input to the beam combination detection unit; the y polarized light is input to the beam combination detection unit through a polarization rotator and a waveguide delay line.

Optionally, in the lidar system, the number of the receiving modules is multiple, and the multiple receiving modules are all configured to receive the returned laser echo signals and divide the laser echo signals into x-polarized light and y-polarized light; the number of the beam combination detection units is consistent with that of the receiving modules, and the beam combination detection units are in one-to-one correspondence with the receiving modules so as to receive the local oscillation light and the x-polarized light and the y-polarized light output by the receiving modules.

Optionally, in the laser radar system, the beam combining detection unit includes a beam combiner, an optical mixer, and a balance detector; the beam combiner is used for combining the x polarized light in the laser echo signal and the y polarized light subjected to rotation and phase compensation to obtain combined polarized light; the optical mixer is used for carrying out mixing modulation on the local oscillation light and the polarized light after beam combination so as to obtain a mixing signal; the balance detector is used for generating beat current according to the mixing signal.

Optionally, in the lidar system, the signal processing module includes a conversion unit and a processing unit; the conversion unit is used for amplifying the beat frequency current and converting the beat frequency current into beat frequency voltage; the processing unit is used for processing the beat frequency voltage to obtain radar detection information of the detected object.

The laser radar system provided by the invention comprises: the light source generation module is used for providing a laser signal; the optical path conversion module is integrated on a silicon optical chip and is used for converting a laser signal to generate and send a laser emission signal, receiving a returned laser echo signal and converting the laser echo signal into beat current; the signal processing module is used for processing the beat frequency current to obtain radar detection information of the detected object; the control module is used for supplying power to the light source generation module, the light path conversion module and the signal processing module and controlling the light source generation module, the light path conversion module and the signal processing module. The optical path conversion module with the largest volume and higher cost is integrated on the silicon optical chip, so that the volume of the laser radar system is effectively reduced, and the manufacturing cost can be reduced to a certain extent; meanwhile, after the optical path conversion module is integrated on the silicon optical chip, the precision of each device is higher, and the device is not easy to wear, so that the reliability of the laser radar system can be effectively improved, and the problems of large volume, high cost and lower reliability of the existing laser radar system are solved.

Drawings

Fig. 1 is a block diagram of a laser radar system according to the present embodiment;

fig. 2 is a schematic diagram of a specific structure of a first lidar system according to the present embodiment;

fig. 3 is a schematic diagram of a specific structure of a second lidar system according to the present embodiment;

fig. 4 is a schematic structural diagram of a third lidar system according to the present embodiment.

Detailed Description

The lidar system according to the invention is described in further detail below with reference to the drawings and to specific embodiments. It should be noted that the drawings are in a very simplified form and are all to a non-precise scale, merely for convenience and clarity in aiding in the description of embodiments of the invention. Furthermore, the structures shown in the drawings are often part of actual structures. In particular, the drawings are shown with different emphasis instead being placed upon illustrating the various embodiments.

It is noted that "first", "second", etc. in the description and claims of the present invention and the accompanying drawings are used to distinguish similar objects so as to describe embodiments of the present invention, and not to describe a specific order or sequence, it should be understood that the structures so used may be interchanged under appropriate circumstances. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The silicon optical chip is a carrier for information transmission or data operation by using light waves, and generally relies on integrated optics or silicon-based optoelectronics to transmit guided-mode optical signals through medium optical waveguides, so that modulation, transmission, demodulation and the like of optical signals and electric signals are integrated on the same substrate or chip. Photonic integrated circuits and optical interconnects exhibit lower transmission loss, wider transmission bandwidth, smaller time delay, and stronger electromagnetic interference resistance than electronic integrated circuits or electrical interconnect technologies; in addition, optical interconnects may also increase the communication capacity within the transmission medium by using multiple multiplexing modes (e.g., wavelength division multiplexing WDM, mode division multiplexing MDM, etc.).

Based on this, the present embodiment provides a lidar system, as shown in fig. 1, including: the light source generation module is used for providing a laser signal; the optical path conversion module is integrated on a silicon optical chip and is used for converting a laser signal to generate and send a laser emission signal, receiving a returned laser echo signal and converting the laser echo signal into beat current; the signal processing module is used for processing the beat frequency current to obtain radar detection information of the detected object; the control module is used for supplying power to the light source generation module, the light path conversion module and the signal processing module and controlling the light source generation module, the light path conversion module and the signal processing module.

According to the laser radar system provided by the embodiment, the optical path conversion module with the largest volume and higher cost is integrated on the silicon optical chip, so that the volume of the laser radar system is effectively reduced, and the manufacturing cost can be reduced to a certain extent; meanwhile, after the optical path conversion module is integrated on the silicon optical chip, the precision of each device is higher, and the device is not easy to wear, so that the reliability of the laser radar system can be effectively improved, and the problems of large volume, high cost and lower reliability of the existing laser radar system are solved.

Specifically, in this embodiment, the light source generating module includes a laser and an optical amplifier; the laser is used for providing a laser beam with a wavelength adjustment range of more than 100 nm; the optical amplifier is used for amplifying the energy of the laser beam emitted by the laser to provide a laser signal, wherein the laser signal is a coherent frequency modulation signal. In practical applications, the laser may specifically output laser with a center wavelength of 1550nm, and of course, in other practical applications, lasers with other working wavelengths may also be selected, which is not limited in this application.

In practical application, when the laser radar is an FMCW (Frequency-modulated continuous-wave) laser radar, the laser may be a broadband tunable narrow linewidth laser, so as to effectively improve performance of the laser radar system. And the optical amplifier may be an EDFA erbium doped fiber amplifier or an SOA semiconductor optical amplifier. In addition, the light source generating module can be connected with the light path conversion module on the silicon optical chip in a fiber or lens packaging mode. Of course, with the development of technology, the light source generating module may also be integrated on a silicon photo chip.

Further, in this embodiment, the optical path conversion module includes a coupling unit, a beam splitting unit, a calibration unit, a signal transceiver unit, and a beam combination detection unit; the coupling unit is used for receiving the laser signal and coupling the laser signal; the beam splitting unit is used for splitting the coupled laser signals into at least three paths, one path is input to the calibration unit, the rest is input to the beam combining detection unit as local oscillation light, and the rest is input to the signal receiving and transmitting unit; the calibration unit is used for calibrating the frequency modulation nonlinearity of the laser signal; the signal receiving and transmitting unit is used for sending laser emission signals and receiving returned laser echo signals; the beam combination detection unit is used for processing the local oscillation light and the laser echo signal to obtain beat frequency current.

The coupling unit is an end face coupler or an angle coupler, so that high-efficiency coupling of laser signals is realized. In practical applications, a silicon optical end-face coupler may be selected. A silicon optical end-face coupler is a device used for optical fiber communication and integrated optoelectronic chips. In a silicon optical end-face coupler, two optical fibers or optoelectronic chips are brought close to each other and held in a certain relative position. When an optical signal is transferred from one optical fiber or chip to another, the optical signal can be coupled between two adjacent optical structures through close contact, and the coupling phenomenon can enable the optical signal transmission to be more efficient, so that the communication performance is improved.

And, in this embodiment, as shown in fig. 2, the light splitting unit includes a primary light splitter, a secondary light splitter, and a tertiary light splitter; the first-order beam splitter is connected with the optical path of the coupling unit so as to split the coupled laser signals into two paths; the second-stage beam splitter is connected with the first-stage beam splitter in a light path so as to divide one path of laser sub-signal split by the first-stage beam splitter into two paths, wherein one path of the laser sub-signal is directly connected with the light path of the calibration unit, and the other path of the laser sub-signal is connected with the light path of the calibration unit through an optical waveguide delay line; the three-stage beam splitter is connected with the optical path of the first-stage beam splitter so as to divide the other path of laser sub-signals split by the first-stage beam splitter into two paths, wherein one path of laser sub-signals is used as local oscillation light to be input to the beam combination detection unit, and the other path of laser sub-signals are input to the signal receiving and transmitting unit.

In the practical application process, the first-stage beam splitter, the second-stage beam splitter and the third-stage beam splitter can be formed by beam splitting prisms, and of course, the beam splitting prism can also be realized by using optical components with other beam splitting functions.

Preferably, the energy of the two light paths separated by each level of beam splitter can be set according to practical situations, for example, in the three levels of beam splitters, one path of energy used as local oscillation light can be 10%, and the other 90% of energy is input to the signal receiving and transmitting unit, so that the laser emission signal sent by the laser radar system is ensured to have enough intensity to reach the surface of the detected object. The above examples are only to illustrate one possible implementation of the energy distribution, and in practical applications, the energy distribution of each path after splitting of each stage of the splitter needs to be set according to practical situations, which is not limited in this application.

Further, in this embodiment, as shown in fig. 2, the calibration unit includes an optical mixer and a balance detector; two paths of laser sub-signals separated by the two-stage optical splitter enter an optical mixer and then are subjected to mixing tuning so as to obtain a mixed signal; the balance detector generates beat current by using the mixing signal and inputs the beat current to the signal processing module. The calibration unit provided by the embodiment is a nonlinear calibration unit, and can provide a triangular wave frequency modulation signal with almost ideal linearity, so that the detection precision of a laser radar system can be effectively improved. In practical applications, the optical mixer may be a 2×2 mixer.

In this embodiment, the signal transceiver unit includes an auto-collimation transmitting module and a receiving module; the self-collimation transmitting module comprises a beam splitter, a phase modulator and a transmitting antenna, so as to modulate a laser signal to obtain a laser transmitting signal and transmit the laser transmitting signal; the receiving module is used for receiving the returned laser echo signals and dividing the laser echo signals into x polarized light (corresponding to TE modes in the waveguide) and y polarized light (corresponding to TM modes in the waveguide).

In practical application, the auto-collimation transmitting module is an OPA (Optical phased array ) auto-collimation transmitting module, and comprises a beam splitter, a phase modulator and a transmitting antenna. The OPA realizes free space high-directivity beam in a far-field interference mode by integrating a large number of transmitting optical antennas on a silicon optical chip, so that the OPA has the characteristic of auto-collimation; in addition, the OPA can regulate and control the phase of each transmitting antenna in the array in an electric control mode, so that the scanning of transmitting beams is realized, the mechanical parts of the system are completely eliminated, meanwhile, the problem of walk-off effect in a rotating mirror scanning system is avoided, and the method is a pure solid scheme, and therefore the reliability of a laser radar system is effectively improved.

The OPA auto-collimation transmitting module provided by the embodiment reasonably regulates and controls the wave front phase of each channel through controlling the channel voltage, and can realize beam auto-collimation and scanning. By changing the input wavelength, free space two-dimensional beam scanning can be achieved using the dispersive properties of the grating.

In a specific embodiment, the beam splitter may be set to N stages, corresponding to 2 ^N A phase modulator, and a transmitting antenna disposed after each phase modulator.

Preferably, the phase modulator is a phase shifter based on a thermo-optical or electro-optical effect, and the transmitting antenna is in the form of a long-wave waveguide grating antenna, so that the accuracy of signal phase shifting and the intensity of signal transmission are ensured.

In the lidar system shown in fig. 2, the receiving module includes a first optical phased array and a second optical phased array; the first optical phased array is used for receiving the x-polarized light and inputting the received x-polarized light to the beam combination detection unit; the second optical phased array is used for receiving y polarized light and inputting the received y polarized light to the beam combination detection unit through the polarization rotator and the phase tuner. In this way, the y polarized light is converted into x polarized light after passing through the polarization rotator, and then the phase tuner is used for compensating the phase difference generated by the space between the y polarized light and the x polarized light and the transmission on the chip, so that the polarization of the y polarized light is consistent with that of the x polarized light.

Preferably, the first optical phased array and the second optical phased array need to perform beam pointing control through the control module so as to receive echo signals in a specific direction, and receiving efficiency is improved.

It should be noted that, after the laser emission signal is reflected and scattered by the probe, due to the depolarization effect of the object, the laser echo signal has two orthogonal polarizations, that is, the laser echo signal contains x-polarized light and y-polarized light. Because the prior art only acquires x polarized light, the energy of y polarized light is wasted, so that the intensity of the x polarized light is poor, and the signal-to-noise ratio and the accuracy of a laser radar system are low; the method and the device not only acquire the x polarized light, but also acquire the y polarized light, convert the y polarized light into the x polarized light by carrying out polarization rotation and phase compensation on the y polarized light, and effectively improve the intensity of the x polarized light by beam combination, thereby effectively improving the signal-to-noise ratio of a laser radar system and further improving the precision of the laser radar system.

Still further, in this embodiment, the beam combining detection unit includes a beam combiner, an optical mixer, and a balance detector; the beam combiner is used for combining the x polarized light in the laser echo signal and the y polarized light subjected to rotation and phase compensation to obtain combined polarized light; the optical mixer is used for carrying out mixing modulation on the local oscillation light and the polarized light after beam combination so as to obtain a mixing signal; the balance detector is used for generating beat current according to the mixing signal. Therefore, after the polarization rotator and the phase tuner are tuned, y polarized light is converted into x polarized light, and the two are combined by the beam combiner, so that the signal intensity of the x polarized light can be effectively improved; and the polarization of the local oscillation light is consistent with that of the x polarization light, so that after the local oscillation light and the polarization light after beam combination enter the optical mixer together, the signal intensity can be further improved, an optical signal can be converted into a mixing signal through the optical mixer, and finally beat frequency current is generated according to the mixing signal through the balance detector.

And, in this embodiment, the signal processing module includes a conversion unit and a processing unit; the conversion unit is used for amplifying the beat frequency current and converting the beat frequency current into beat frequency voltage; the processing unit is used for processing the beat frequency voltage to obtain radar detection information of the detected object, wherein the radar detection information comprises distance information, instantaneous speed information and the like of the detected object.

In practical application, the conversion unit can be a TIA (transimpedance amplifier), and the TIA is utilized to convert the beat current into the beat voltage, so that the high-frequency voltage conversion circuit has high conversion rate, simple circuit structure and low power consumption, and in addition, the high-frequency conversion performance can be obtained. And the processing unit can be a DSP (digital signal processor), and the DSP is a special microprocessor chip, so that the energy efficiency is better, and the energy consumption can be effectively reduced.

As a variation of the lidar system shown in fig. 2, as shown in fig. 3, in the lidar system, the receiving module includes a grating antenna and a Polarizing Beam Splitter (PBS); the grating antenna is used for receiving the laser echo signals; the polarization beam splitter is used for dividing the laser echo signal into x polarized light and y polarized light, and the x polarized light is directly input to the beam combination detection unit; the y polarized light is input to the beam combination detection unit through a polarization rotator and a waveguide delay line. In this way, the laser echo signal is completely received through the grating antenna, then the laser echo signal is divided into x polarized light and y polarized light by the polarization beam splitter, then the y polarized light is converted into x polarized light by the polarization rotator, and finally, as the same receiving antenna (grating antenna) is adopted, no phase difference is generated when two orthogonal polarized signals propagate in free space, only the phase difference generated by transmission of the y polarized light after polarization rotation and the x polarized light directly received by the grating antenna is compensated by the on-chip optical waveguide delay line, so that the polarization of the y polarized light is consistent with that of the x polarized light.

Preferably, in order to obtain a wider beam with a flatter profile, in this embodiment, the grating antenna has a smaller radiation aperture, and typically the 3-dB beam width of the grating antenna needs to cover the scanning range of the auto-collimation emission module. In target detection, the probe may be considered a lambertian reflector that scatters incident energy into the angular region of 2π range, so that when the beam width of a single grating antenna is sufficiently wide, it is able to receive laser echo signals from incident in a wide range of angles.

Further, in order to improve the signal-to-noise ratio and the maximum detection distance of the laser radar system, and expand the number of channels of the received signal, so as to expand the receiving field of view range of the receiving end and improve the detection confidence, in this embodiment, as shown in fig. 4, the number of the receiving modules is multiple, and the multiple receiving modules are all used for receiving the returned laser echo signal, and divide the laser echo signal into x polarized light and y polarized light; the number of the beam combination detection units is consistent with that of the receiving modules, and the beam combination detection units are in one-to-one correspondence with the receiving modules so as to receive the local oscillation light and the x-polarized light and the y-polarized light output by the receiving modules.

In the lidar system shown in fig. 4, a scheme of matching the grating antenna shown in fig. 3 with the polarization beam splitter is adopted by the multiple receiving modules. In other implementations, the multiple receiving modules may also adopt the schemes of the first optical phased array and the second optical phased array shown in fig. 2; or, the schemes of fig. 2 and fig. 3 may be combined, that is, a part of the receiving modules adopt a receiving module formed by the first optical phased array and the second optical phased array shown in fig. 2, and the rest part adopts a receiving module which adopts the grating antenna shown in fig. 3 and matches with the receiving module of the polarization beam splitter. The scheme of the receiving module specifically adopted by the method is not limited in this application, and the number of the receiving modules can be set according to actual conditions.

Preferably, when the plurality of receiving modules adopt the grating antennas shown in fig. 3 in combination with the receiving modules of the polarization beam splitter, the spacing between the grating antennas can be set larger, so as to provide a wider receiving field of view.

In order to provide corresponding local oscillation light for the beam combination detection units corresponding to the plurality of receiving modules, in this embodiment, the three-stage beam splitter includes a plurality of sub-beam splitters connected in a hierarchy, each sub-beam splitter splits an optical signal received from a previous hierarchy into two paths, one path is used as the local oscillation light to be input to the beam combination detection unit, and the other path is used as the local oscillation light to be input to the signal receiving and transmitting unit. The number of the sub-optical splitters is consistent with that of the receiving modules and corresponds to that of the receiving modules one by one, so that local oscillation light split by the current sub-optical splitters is input to the corresponding beam combination detection units.

In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the difference from other embodiments, so that the same similar parts of each embodiment are referred to each other.

The laser radar system provided in this embodiment includes: the light source generation module is used for providing a laser signal; the optical path conversion module is integrated on a silicon optical chip and is used for converting a laser signal to generate and send a laser emission signal, receiving a returned laser echo signal and converting the laser echo signal into beat current; the signal processing module is used for processing the beat frequency current to obtain radar detection information of the detected object; the control module is used for supplying power to the light source generation module, the light path conversion module and the signal processing module and controlling the light source generation module, the light path conversion module and the signal processing module. The optical path conversion module with the largest volume and higher cost is integrated on the silicon optical chip, so that the volume of the laser radar system is effectively reduced, and the manufacturing cost can be reduced to a certain extent; meanwhile, after the optical path conversion module is integrated on the silicon optical chip, the precision of each device is higher, and the device is not easy to wear, so that the reliability of the laser radar system can be effectively improved, and the problems of large volume, high cost and lower reliability of the existing laser radar system are solved.

The above description is only illustrative of the preferred embodiments of the present invention and is not intended to limit the scope of the present invention, and any alterations and modifications made by those skilled in the art based on the above disclosure shall fall within the scope of the appended claims.

Claims

1. A lidar system, comprising:

the light source generation module is used for providing a laser signal;

2. The lidar system of claim 1, wherein the light source generation module comprises a laser and an optical amplifier; the laser is used for providing a laser beam with a wavelength adjustment range of more than 100 nm; the optical amplifier is used for amplifying the energy of the laser beam emitted by the laser to provide a laser signal.

3. The lidar system according to claim 1, wherein the optical path conversion module comprises a coupling unit, a beam splitting unit, a calibration unit, a signal transceiving unit, and a beam combining detection unit; the coupling unit is used for receiving the laser signal and coupling the laser signal; the beam splitting unit is used for splitting the coupled laser signals into at least three paths, one path is input to the calibration unit, the rest is input to the beam combining detection unit as local oscillation light, and the rest is input to the signal receiving and transmitting unit; the calibration unit is used for calibrating the frequency modulation nonlinearity of the laser signal; the signal receiving and transmitting unit is used for sending laser emission signals and receiving returned laser echo signals; the beam combination detection unit is used for processing the local oscillation light and the laser echo signal to obtain beat frequency current.

4. The lidar system according to claim 3, wherein the spectroscopic unit comprises a primary spectroscopic unit, a secondary spectroscopic unit, and a tertiary spectroscopic unit; the first-order beam splitter is connected with the optical path of the coupling unit so as to split the coupled laser signals into two paths; the second-stage beam splitter is connected with the first-stage beam splitter in a light path so as to divide one path of laser sub-signal split by the first-stage beam splitter into two paths, wherein one path of the laser sub-signal is directly connected with the light path of the calibration unit, and the other path of the laser sub-signal is connected with the light path of the calibration unit through an optical waveguide delay line; the three-stage beam splitter is connected with the optical path of the first-stage beam splitter so as to divide the other path of laser sub-signals split by the first-stage beam splitter into two paths, wherein one path of laser sub-signals is used as local oscillation light to be input to the beam combination detection unit, and the other path of laser sub-signals are input to the signal receiving and transmitting unit.

5. The lidar system of claim 4, wherein the three-stage optical splitter comprises a plurality of sub-optical splitters connected in a hierarchy, each of the sub-optical splitters splits an optical signal received from a previous hierarchy into two paths, one path being input as local oscillation light to the beam combining detection unit, and the other path being input to the signal transceiving unit.

6. The lidar system according to claim 3, wherein the signal transceiving unit comprises an auto-collimation transmitting module and a receiving module; the self-collimation transmitting module comprises a beam splitter, a phase modulator and a transmitting antenna, so as to modulate a laser signal to obtain a laser transmitting signal and transmit the laser transmitting signal; the receiving module is used for receiving the returned laser echo signals and dividing the laser echo signals into x polarized light and y polarized light.

7. The lidar system of claim 6, wherein the receive module comprises a first optical phased array and a second optical phased array; the first optical phased array is used for receiving the x-polarized light and inputting the received x-polarized light to the beam combination detection unit; the second optical phased array is used for receiving y polarized light and inputting the received y polarized light to the beam combination detection unit through the polarization rotator and the phase tuner.

8. The lidar system of claim 6, wherein the receive module comprises a grating antenna and a polarizing beam splitter; the grating antenna is used for receiving the laser echo signals; the polarization beam splitter is used for dividing the laser echo signal into x polarized light and y polarized light, and the x polarized light is directly input to the beam combination detection unit; the y polarized light is input to the beam combination detection unit through a polarization rotator and a waveguide delay line.

9. The lidar system of claim 6, wherein the number of receiving modules is a plurality, wherein each of the plurality of receiving modules is configured to receive the returned laser echo signal and split the laser echo signal into x-polarized light and y-polarized light; the number of the beam combination detection units is consistent with that of the receiving modules, and the beam combination detection units are in one-to-one correspondence with the receiving modules so as to receive the local oscillation light and the x-polarized light and the y-polarized light output by the receiving modules.

10. The lidar system according to claim 3, wherein the beam combining detection unit comprises a beam combiner, an optical mixer, and a balance detector; the beam combiner is used for combining the x polarized light in the laser echo signal and the y polarized light subjected to rotation and phase compensation to obtain combined polarized light; the optical mixer is used for carrying out mixing modulation on the local oscillation light and the polarized light after beam combination so as to obtain a mixing signal; the balance detector is used for generating beat current according to the mixing signal.

11. The lidar system of claim 1, wherein the signal processing module comprises a conversion unit and a processing unit; the conversion unit is used for amplifying the beat frequency current and converting the beat frequency current into beat frequency voltage; the processing unit is used for processing the beat frequency voltage to obtain radar detection information of the detected object.