Optical modules, optical detection and range determination, and terminals.

Abstract

Invention details;

Description

Optical modules, lidar and terminals

[0001] This application claims priority to the Chinese patent application filed with the State Intellectual Property Office of China on October 10, 2023, with application number 202311306196.2 and application name “Optical module, lidar and terminal”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of detection technology, and in particular to optical modules, laser radars and terminals. Background Art

[0003] With the development of information technology and computer vision, detection technology has made rapid progress. A wide variety of detection devices have brought great convenience to people's lives and travel. Detection devices can be thought of as the "eyes" that perceive the environment. These include visual sensors such as cameras and radar sensors such as millimeter-wave radar, laser radar, and ultrasonic radar. Among them, laser radar (light detection and ranging, or Lidar) boasts high resolution, excellent detection performance, and strong concealment. It plays a crucial role in environmental perception and has been widely used in the field of intelligent driving, contributing to the further development of intelligent driving technology. Coherent laser radar uses frequency-modulated light as a transmitting signal for target detection. It processes the local oscillation (LO) of the transmitted signal and the return signal to obtain relevant information about the target. The laser carrier of a coherent laser radar is often modulated in a certain pattern, causing the frequency to vary over time. This pattern can be sawtooth, triangular, or sinusoidal. A laser radar whose frequency of the emitted light beam changes linearly is called a frequency modulated continuous wave (FMCW) laser radar. It combines laser linear frequency sweep ranging technology and scanning imaging technology, has unique speed detection advantages, and is widely used in intelligent driving scenarios.

[0004] The laser radar includes a transmitting end and a receiving end, and because it needs to transmit and receive lasers, a variety of optical components need to be set up inside it to process the light beam. Especially for FMCW laser radar, coherent components (such as the optical path for transmitting LO, the return signal and the mixing components of LO, etc.) are required to support coherent detection. Laser radar is often carried on a mobile terminal. If the laser radar is large, it will take up a large space, which may affect the aesthetics of the mobile terminal and the user's riding comfort. In some solutions, the overall volume of the laser radar is increased by reducing the optical path length of the laser radar and using small optical components. However, this method often reduces the diameter of the light beam emitted by the laser radar, so that the light spot formed by the emitted light beam is relatively small, resulting in a decrease in the detection performance of the laser radar.

[0005] How to reduce the size of the laser radar without reducing its detection performance is a hot issue being studied by technicians in this field.

[0006] Summary of the Invention

[0007] The embodiments of the present application provide an optical module, a laser radar, and a terminal, which can reduce the volume of the detection device without reducing the detection performance of the laser radar.

[0008] In a first aspect, embodiments of the present application provide an optical module comprising N transmitting ports, N receiving ports, a beam processing module, and a beam expansion module, where N is an integer greater than or equal to 0. The N transmitting ports are configured to transmit N transmitting beams, and the N receiving ports are configured to receive return beams from the N transmitting beams. The beam processing module is configured to transmit the N transmitting beams to the beam expansion module, and to deflect and propagate the N return beams from the beam expansion module to the N receiving ports. The beam expansion module is configured to expand the N transmitting beams.

[0009] Among them, the N return beams are the return beams of the N emission beams, and the N emission beams passing through the beam processing module and the N return beams from the beam expansion module are coaxial beams.

[0010] An embodiment of the present application proposes an optical module comprising a two-stage optical system, wherein the beam processing module is a first-stage optical system and the beam expansion module is a second-stage optical system. The first-stage optical system is used to achieve the coaxiality of the emitted light beam and the return light beam, and to deflect the return light beam so that the return light beam can be received by the receiving port. The second-stage optical system is used to amplify the emitted light beam (i.e., expand the beam), thereby increasing the diameter of the emitted light beam to meet the requirements of light output collimation and receiving aperture. Furthermore, since the optical path is reversible, the emitted light beam is expanded by passing through the beam expansion module, and the return light beam can be contracted after passing through the beam expansion module in the reverse direction of the optical path of the emitted light beam.

[0011] On the one hand, since the diameters of the emitted light beam before passing through the beam expansion module and the return light beam after passing through the beam expansion module are relatively small, the size of the light beam processing module can also be designed to be relatively small, thereby reducing the overall volume of the light beam module. Moreover, when the size of the light beam is relatively small, the process tolerance angle of the optical components for achieving coaxiality is also relatively high, and the engineering implementation is less difficult. On the other hand, the aperture of the second-stage optical system is relatively large, which can meet the needs of large-diameter light emission and light collection, and ensure detection performance. Moreover, since the first-stage optical system has achieved coaxial transmission and reception, the emitted light beam and the return light beam can share the same set of second-stage optical systems, which can further reduce the overall volume of the optical module. In summary, when the optical module is applied to a detection device, the overall size of the detection device can be significantly reduced, thereby enhancing the application value of the detection device.

[0012] In conjunction with the first aspect, in one possible implementation of the first aspect, N transmit ports and N receive ports can be integrated into the same module. In some solutions, the N transmit ports and N receive ports are implemented using an optical fiber array or a waveguide chip. For example, the N transmit ports and N receive ports can be provided on one end face of the waveguide chip.

[0013] Furthermore, the N transmitting ports and the N receiving ports may be arranged along the first direction. Alternatively, when N>1, the N receiving ports may be arranged along the first direction on the end face of the module, and the N transmitting ports and the N receiving ports may be arranged on the same end face or on different end faces.

[0014] Since FMCW requires mixing the LO corresponding to the transmitted light beam and the return light beam, by integrating N transmitting ports and N receiving ports on the same module, the device integration level of the detection device based on FMCW technology can be greatly improved, and the size of the entire device can be further reduced.

[0015] In conjunction with the first aspect, in another possible implementation of the first aspect, the N transmit ports and the N receive ports may be integrated into different modules. Furthermore, when N>1, the N receive ports may be arranged along a first direction on an end face of the module. In this case, the N transmit ports and the N receive ports may be provided on the same end face or on different end faces.

[0016] In combination with the first aspect, in another possible implementation of the first aspect, the beam processing module includes a polarization beam splitter PBS and a quarter wave plate (QWP), and the QWP is arranged on the optical path between the PBS and the beam expansion module.

[0017] Among them, N transmitted light beams are transmitted through the PBS and QWP to the beam expansion module, and N return light beams from the beam expansion module are transmitted through the QWP to the PBS.

[0018] In this way, the transmitted light beam and the returned light beam are separated based on the PBS and the wave plate, coaxial transmission and reception are achieved, and the beam loss in the coaxial process is significantly reduced.

[0019] Alternatively, the QWP can be replaced by two eighth-wave plates, or a QWP plus a half-wave plate (HWP).

[0020] In combination with the first aspect, in another possible implementation of the first aspect, the beam processing module further includes an HWP, and the HWP is arranged on the optical path between the PBS and the N receiving ports. On the one hand, the polarization direction of the N return beams can be adjusted by the HWP, and the polarization direction of the return beam can be made the same as that of the emitted beam in combination with the QWP. In particular, when the transmitting port and the receiving port are implemented by a waveguide chip (or optical fiber array), when the waveguide (or optical fiber) maintains polarization in a certain polarization direction, the combination of the HWP and the QWP can make the polarization direction of the return beam the same as that of the emitted beam, and further make the return beam and the polarization maintaining direction of the waveguide the same, which is beneficial to reduce the loss caused by the transmission of the return beam in the waveguide (or optical fiber) and improve the detection performance. On the other hand, the combination of the HWP and the QWP has an achromatic dispersion effect in certain scenarios, which can further improve the detection accuracy.

[0021] In conjunction with the first aspect, in another possible implementation of the first aspect, the PBS is configured to transmit a light beam having a first polarization direction and reflect a light beam having a second polarization direction. The first polarization direction is perpendicular to the second polarization direction. Specifically, the PBS can transmit light having a polarization direction parallel to that of the PBS (referred to as P-polarized light, i.e., a light beam having the first polarization direction), and reflect (or block) light having a polarization direction perpendicular to that of the PBS (referred to as S-polarized light, i.e., a light beam having the second polarization direction).

[0022] The QWP is used to change the polarization direction of the passing light beam. The polarization direction of the return light beam of the N emitted light beams after passing through the QWP is perpendicular to the polarization direction of the N emitted light beams. For example, the N emitted light beams transmitted by the PBS are P-polarized light, which is provided to the object space after passing through the QWP. The light beams returning from the object space (such as the N return light beams) can be S-polarized light after passing through the QWP again, and the S-polarized light is reflected after passing through the PBS. In this way, coaxial transmission and reception can be achieved, and the beam loss in the coaxial process can be significantly reduced.

[0023] Alternatively, in this embodiment, the QWP can be replaced by two eighth-wave plates. Alternatively, in this embodiment, the QWP can be replaced by one QWP plus one HWP.

[0024] In combination with the first aspect, in another possible implementation of the first aspect, the beam processing module further includes a folding mirror, which is used to deflect the beam passing through the PBS and propagate it to the N receiving ports. Furthermore, the HWP can be arranged between the PBS and the folding mirror.

[0025] In combination with the first aspect, in another possible implementation of the first aspect, the optical module further includes a scanning module. The scanning module is movable so as to emit and receive light beams at multiple angles.

[0026] Furthermore, the scanning module is used to scan the N emission light beams passing through the beam expansion module to the object space, and to propagate the return light beams of the N emission light beams from the object space to the beam expansion module.

[0027] In conjunction with the first aspect, in yet another possible implementation of the first aspect, N ≥ 2, the N return light beams after passing through the scanning module are arranged along the first direction, and the scanning direction of the scanning module is a second direction. The walk-off angle direction of each of the N return light beams is the second direction, and the second direction is different from the first direction.

[0028] Furthermore, the optical module further includes a spot transfer mechanism for transferring the walk-off angle of each of the N return beams to be aligned with the arrangement of the N return beams. Optionally, the spot transfer mechanism is disposed in the optical path between the scanning module and the N receiving ports. For example, if the beam processing module includes a PBS, the spot transfer mechanism can be disposed between the beam expansion module and the PBS, or between the PBS and the N receiving ports.

[0029] In the above implementation, N transmitted light beams are irradiated onto a scanner. After being scanned by the scanner at a certain angle onto a target in the object space, they are reflected by the target in the object space to produce corresponding return light beams. Because the scanner continuously scans, and there is a certain distance between the target in the object space and the scanner, when the return light beam returns and passes through the scanner, the scanner has already rotated a certain angle, causing the return light beam to no longer propagate along the original direction of the N return light beams, but instead has a certain deviation angle, namely the walkoff angle. It is not difficult to see that the angular direction of the walkoff angle is the same as the scanning direction of the scanning module. Since the N transmitted light beams form a linear array, during scanning, the scanning direction (or fast axis direction) of the scanning module is generally different from the arrangement direction of the N transmitted light beams, while the arrangement direction of the N return light beams is the same as the arrangement direction of the N transmitted light beams. Therefore, it is easy to conclude that the angular direction of the walkoff angle is different from the arrangement direction of the N transmitted light beams.

[0030] In the embodiment of the present application, the light spot transposition mechanism adjusts the direction of the walk-off angle to the arrangement direction of the N return beams. Since it is difficult to compensate for the walk-off angle of the N receiving ports in a direction perpendicular to the arrangement direction of the ports, after the walk-off angle is adjusted to the arrangement direction of the N return beams, the angular offset of the N return beams caused by the walk-off angle can be compensated by staggering them in the arrangement direction of the N receiving ports. This can help reduce signal loss caused by the walk-off angle and improve signal effectiveness.

[0031] In some cases, if the scanner is stationary, the return beams of the N transmitted beams will propagate along the optical path of the ideal return beam, and the walk-off angle is 0°. Therefore, in some cases, the scanner is active, and the offset angle (i.e., the walk-off angle) of the N return beams from the ideal return beam is a first angle (the first angle is greater than 0°). At this time, if the N receiving ports are set on the optical path of the ideal return beam, it will be difficult for the light spots of the N return beams to accurately enter the receiving ports, resulting in light spot loss. Therefore, the receiving ports are offset along the arrangement direction of the ports to compensate for the offset of the N return beams, so that the light spots of the N return beams can be closer to the effective receiving area of ​​the receiving port, or even coincide with the center of the receiving port. In this way, the N receiving ports can more accurately receive the N return beams, thereby improving the effectiveness of the received echo signals and improving the detection performance.

[0032] In combination with the first aspect, in another possible implementation of the first aspect, the light spot transposition mechanism includes a stepped reflector, which includes N reflective surfaces arranged in a stepped manner along the arrangement direction of the N return light beams, and each reflective surface is used to reflect one light beam.

[0033] In combination with the first aspect, in another possible implementation of the first aspect, the light spot transposition mechanism includes a first stepped reflector and a second stepped reflector, wherein:

[0034] The first stepped reflector includes N first reflective surfaces arranged in a stepped manner. The first stepped reflector includes N second reflective surfaces arranged in a stepped manner, the N first reflective surfaces are opposite to the N second reflective surfaces one by one, and the second stepped reflector is used to reflect the emitted light of the first group of stepped reflectors again.

[0035] In combination with the first aspect, in yet another possible implementation of the first aspect, each of the N first reflection surfaces is configured to fold one of the N return light beams and propagate the beam to one of the N second reflection surfaces. Each of the N second reflection surfaces is configured to fold one of the N return light beams so that a walk-off angle of the one return light beam is along an arrangement direction of the N return light beams.

[0036] In combination with the first aspect, in another possible implementation of the first aspect, the N first reflection surfaces are not parallel to the walk-off angle directions of the N return light beams. Further, the N second emission surfaces are not parallel to the walk-off angle directions of the N return light beams.

[0037] Exemplarily, non-parallel includes perpendicular.

[0038] In combination with the first aspect, in another possible implementation of the first aspect, the angle between the N first reflecting surfaces and the bottom surface of the first stepped reflector is 45°, and the angle between the N second reflecting surfaces and the bottom surface of the second stepped reflector is 45°.

[0039] In combination with the first aspect, in another possible implementation of the first aspect, an angle between the N first reflecting surfaces and the bottom surface of the first stepped reflector is 45°;

[0040] The included angles between the N second reflecting surfaces and the bottom surface of the first stepped reflecting mirror gradually increase from the step center of the second stepped reflecting mirror along both sides of the step of the second stepped reflecting mirror.

[0041] In combination with the first aspect, in another possible implementation of the first aspect, the light spot transposition mechanism is a prism, and the N first reflection surfaces and the N second reflection surfaces are realized by coating a reflection film in the prism.

[0042] In combination with the first aspect, in another possible implementation of the first aspect, the first stepped reflector includes a first substrate and N first reflectors, the N first reflectors are attached to the first substrate, and each first reflector includes a first reflective surface;

[0043] The second stepped reflector includes a second substrate and N second reflectors. The N second reflectors are attached to the second substrate, and each second reflector includes a first reflective surface.

[0044] In combination with the first aspect, in another possible implementation of the first aspect, the beam expansion module includes a first lens group and a second lens group, and the first lens group and the second lens group have a common focal plane.

[0045] In combination with the first aspect, in another possible implementation of the first aspect, the light spot transfer mechanism is disposed between the first lens group and the second lens group.

[0046] In combination with the first aspect, in another possible implementation of the first aspect, the first lens group includes N lenses, and each lens of the N lenses is used to pass one return light beam among the N return light beams.

[0047] In combination with the first aspect, in another possible implementation of the first aspect, the optical module further includes a transmitting lens group and a receiving lens group, the transmitting lens group is arranged between the N transmitting ports and the beam expansion module, and the receiving lens group is arranged between the N receiving ports and the beam expansion module;

[0048] N transmitting ports, transmitting lens groups, N receiving ports, receiving lens groups and beam processing components are packaged as a first optical component, and the beam expansion module is packaged as a second optical component. The first optical component and the second optical component are provided with light-transmitting windows, which are used to pass N transmitting light beams and N return light beams.

[0049] In combination with the first aspect, in another possible implementation of the first aspect, the N transmitting ports and the N receiving ports are waveguide ports of a waveguide chip.

[0050] In combination with the first aspect, in another possible implementation of the first aspect, the N emission light beams are FMCW lasers.

[0051] In a second aspect, an embodiment of the present application further provides an optical module, the optical module including a beam transceiver module and a light spot transposition mechanism;

[0052] The beam transceiver module includes N transmitting ports and N receiving ports, and the N transmitting ports and the N receiving ports are cross-arranged along the end face of the beam transceiver module, where N is an integer greater than 1.

[0053] The N transmitting ports are used to transmit N transmitting light beams, and the N receiving ports are used to receive N return light beams, where the N return light beams are return beams of the N transmitting light beams. A spot transposition mechanism is disposed in the optical path of the N transmitting light beams and the N return light beams. The N transmitting light beams after passing through the spot transposition mechanism are used to scan the object space in a second direction. The N return light beams before passing through the spot transposition mechanism have a walk-off angle direction in a second direction. The N return light beams are arranged along a first direction, which is different from the first direction. The spot transposition mechanism is used to fold the walk-off angle direction of each of the N return light beams to be aligned with the arrangement direction of the N return light beams and provide the direction to the N receiving ports.

[0054] In conjunction with the second aspect, in a possible implementation of the second aspect, the light spot transposition mechanism includes a first stepped reflector and a second stepped reflector, wherein:

[0055] The first stepped reflector includes N first reflective surfaces arranged in a stepped manner.

[0056] The first stepped reflector includes N second reflective surfaces arranged in a stepped manner, the N first reflective surfaces are opposite to the N second reflective surfaces one by one, and the second stepped reflector is used to reflect the emergent light of the first group of stepped reflectors again.

[0057] In combination with the second aspect, in another possible implementation of the second aspect, each of the N first reflection surfaces is used to fold one of the N return light beams and propagate it to one of the N second reflection surfaces.

[0058] Each of the N second reflection surfaces is used to fold one of the N return light beams so that the walk-off angle direction of the one return light beam is along the arrangement direction of the N return light beams.

[0059] In combination with the second aspect, in another possible implementation of the second aspect, the angle between the N first reflecting surfaces and the bottom surface of the first stepped reflector is 45°, and the angle between the N second reflecting surfaces and the bottom surface of the second stepped reflector is 45°.

[0060] In combination with the second aspect, in another possible implementation of the second aspect, an angle between the N first reflection surfaces and the bottom surface of the first stepped reflector is 45°.

[0061] The included angles between the N second reflecting surfaces and the bottom surface of the first stepped reflecting mirror gradually increase from the step center of the second stepped reflecting mirror along both sides of the step of the second stepped reflecting mirror.

[0062] In combination with the second aspect, in another possible implementation of the second aspect, the light spot transposition mechanism is a prism, and the N first reflection surfaces and the N second reflection surfaces are realized by coating a reflection film in the prism.

[0063] In combination with the second aspect, in another possible implementation of the second aspect, the first stepped reflector includes a first substrate and N first reflectors, the N first reflectors are attached to the first substrate, and each first reflector includes a first reflective surface.

[0064] The second stepped reflector includes a second substrate and N second reflectors. The N second reflectors are attached to the second substrate, and each second reflector includes a first reflective surface.

[0065] In combination with the second aspect, in another possible implementation of the second aspect, the optical module further includes a beam expansion module, which is used to expand the N transmitted light beams and shrink the N return light beams.

[0066] In combination with the second aspect, in another possible implementation of the second aspect, the beam expansion module includes a first lens group and a second lens group, the first lens group and the second lens group have a common focal plane, and the first lens group is arranged on the optical path between the spot device structure and the second lens group.

[0067] In conjunction with the second aspect, in another possible implementation of the second aspect, the beam expansion module includes a first lens group and a second lens group, the first lens group and the second lens group having a common focal plane. Furthermore, the light spot transfer mechanism is disposed on the optical path between the first lens group and the second lens group.

[0068] In combination with the second aspect, in another possible implementation of the second aspect, the first lens group includes N lenses, and each lens of the N lenses is used to pass one of the N return light beams.

[0069] In combination with the second aspect, in another possible implementation of the second aspect, the optical module further includes a transmitting lens group and a receiving lens group, the transmitting lens group is arranged between the N transmitting ports and the beam expansion module, and the receiving lens group is arranged between the N receiving ports and the beam expansion module.

[0070] N transmitting ports, transmitting lens groups, N receiving ports, receiving lens groups and beam processing components are packaged as a first optical component, and the beam expansion module is packaged as a second optical component. The first optical component and the second optical component are provided with light-transmitting windows, which are used to pass N transmitting light beams and N return light beams.

[0071] In combination with the second aspect, in another possible implementation of the second aspect, the N transmitting ports and the N receiving ports are waveguide ports of a waveguide chip.

[0072] In combination with the second aspect, in another possible implementation of the second aspect, the N emission light beams are FMCW lasers.

[0073] In a third aspect, an embodiment of the present application provides a laser radar, which includes the optical module described in any one of the first aspects, or the laser radar includes the optical module described in any one of the second aspects.

[0074] In a possible implementation of the third aspect, the laser radar further includes a light source, for example, a laser.

[0075] In another possible implementation of the third aspect, the laser radar further includes a detector configured to obtain an electrical signal based on the light beam.

[0076] In a fourth aspect, an embodiment of the present application provides a terminal, which includes the optical module of any one of the first aspect, or the optical module of any one of the second aspect, or the laser radar of any one of the third aspect.

[0077] Optionally, the terminal can be an intelligent terminal or transportation tool such as a vehicle, a drone, or a robot. Of course, the terminal can also be replaced by industrial equipment, entertainment and leisure equipment, etc. Intelligent terminals include mobile phones, tablet computers, laptops, smart bracelets, smart watches, or smart glasses. Transportation tools include vehicles, ships, aircraft, or logistics robots. Industrial equipment includes industrial robots and robotic arms. Leisure and entertainment equipment includes virtual reality (VR) equipment, mixed reality (MR) equipment, massage chairs, or 4D cinema cabins. This application does not impose strict restrictions on the devices to which the electrical connector can be applied. BRIEF DESCRIPTION OF THE DRAWINGS

[0078] The following is a brief introduction to the drawings required for describing the embodiments.

[0079] FIG1 is a schematic structural diagram of a detection device based on an off-axis architecture provided in an embodiment of the present application;

[0080] FIG2 is a schematic structural diagram of a detection device based on a coaxial architecture provided in an embodiment of the present application;

[0081] FIG3 is a schematic diagram of an optical module provided in an embodiment of the present application;

[0082] FIG4A is a schematic diagram of a waveguide chip provided in an embodiment of the present application;

[0083] FIG4B is a schematic diagram of an optical path design of a waveguide chip provided in an embodiment of the present application;

[0084] FIG5 is a schematic diagram of another waveguide chip provided in an embodiment of the present application;

[0085] FIG6 is a schematic diagram of another waveguide chip provided in an embodiment of the present application;

[0086] FIG7 is a schematic diagram of another optical module provided in an embodiment of the present application;

[0087] FIG8 is a schematic diagram of another optical module provided in an embodiment of the present application;

[0088] FIG9 is a schematic diagram of two beam expansion modules provided in an embodiment of the present application;

[0089] FIG10 is a schematic structural diagram of another optical module provided in an embodiment of the present application;

[0090] FIG11 is a schematic structural diagram of another optical module provided in an embodiment of the present application;

[0091] FIG12 is a schematic diagram of a walk-off angle provided in an embodiment of the present application;

[0092] FIG13 is a schematic diagram of another walk-off angle provided in an embodiment of the present application;

[0093] FIG14 is a schematic structural diagram of another optical module provided by the present application;

[0094] FIG15 is a schematic diagram of a light spot transposition effect provided by an embodiment of the present application;

[0095] FIG16A is a schematic structural diagram of a stepped reflector provided in an embodiment of the present application;

[0096] FIG16B is a schematic structural diagram of another stepped reflector provided in an embodiment of the present application;

[0097] FIG16C is a schematic structural diagram of another stepped reflector provided in an embodiment of the present application;

[0098] FIG17A is a schematic structural diagram of another light spot transposition mechanism provided in an embodiment of the present application;

[0099] FIG17B is a schematic structural diagram of another light spot transposition mechanism provided in an embodiment of the present application;

[0100] FIG17C is a schematic structural diagram of another light spot transposition mechanism provided in an embodiment of the present application;

[0101] FIG18 is a schematic structural diagram of a transceiver integrated module provided in an embodiment of the present application;

[0102] FIG19 is a schematic structural diagram of another optical module provided in an embodiment of the present application;

[0103] FIG20 is a schematic structural diagram of another optical module provided in an embodiment of the present application;

[0104] FIG21 is a schematic structural diagram of another optical module provided in an embodiment of the present application;

[0105] FIG22 is a schematic diagram of an emission light path of another optical module provided in an embodiment of the present application;

[0106] FIG23 is a schematic structural diagram of an optical module using an off-axis architecture according to an embodiment of the present application;

[0107] FIG24 is a schematic structural diagram of another optical module adopting an off-axis architecture provided in an embodiment of the present application. DETAILED DESCRIPTION

[0108] In recent years, with the increasing demand for intelligent devices and the rapid development of detection technology, detection devices have been widely used in various fields. The detection device here includes a device that detects by emitting a light beam and receiving a light beam returned from the object space. Detection can be understood as obtaining relevant information about targets in the object space. Detection includes but is not limited to one or more detection methods such as target detection, distance measurement, speed measurement, angle measurement, target tracking, and image recognition. For example, the detection device can be a lidar, or a fusion detection device that integrates a lidar and a camera.

[0109] Among them, the detection method of the detection device can include a coherent detection method. Coherent detection technology refers to a method of extracting relevant information of the target based on a mixed signal of two signals (such as LO and return light beam). Since the transmitted light beam changes after being reflected by the target, coherent detection extracts the target information through this change. Coherent detection has advantages in sensitivity, target resolution, and anti-interference. In some schemes, by emitting a frequency modulated continuous wave, the speed of the target can be calculated based on the frequency change of the return light beam and the frequency change of the local oscillator signal of the transmitted light beam.

[0110] The following is an illustrative introduction to the architectures of two detection devices.

[0111] Please refer to Figure 1, which is a structural diagram of a detection device based on an off-axis architecture provided in an embodiment of the present application. The detection device 10 includes a transmitter 101 and a detector 102, and optionally further includes a transmitting optical system and a receiving optical system. Among them, the transmitter 101 can generate a transmission light beam, and the transmission light beam is transmitted to the object space through the transmitting optical system. The transmission light beam is reflected by the target in the object space to form a return light beam, and part of it can enter the receiving optical system and be transmitted to the detector 102. In Figure 1, the transmission light beam and the return light beam have different main optical axes, that is, the optical main axis of the transmission light beam is not collinear with the optical main axis of the return light beam that can be detected by the detector. Therefore, the field of view corresponding to the transmission light beam emitted by the transmitter and the field of view corresponding to the light beam that can be received by the detector are difficult to align.

[0112] Please refer to Figure 2, which is a structural diagram of a detection device based on a coaxial architecture provided in an embodiment of the present application. The detection device 20 includes a transmitter 201, a detector 202 and a coaxial element 203. Among them, the transmitter 201 can generate an emission light beam, and the emission light beam is transmitted to the object space through the emission optical system and the coaxial element 203. The emission light beam is reflected by the target in the object space to form a return light beam, and the return light beam also passes through the coaxial optical element to enter the receiving optical system and is transmitted to the detector 202. In Figure 2, the emission light beam and the return light beam have the same main optical axis, that is, the optical main axis of the emission light beam is collinear with the optical main axis of the return light beam that can be detected by the detector.

[0113] As can be seen from Figures 1 and 2, the detection device needs to emit and return light beams, so a variety of optical elements need to be set up inside to process the light beams. With the user's requirements for the aesthetics, comfort and stability of the terminal, the detection device is increasingly moving towards miniaturization and integration. How to reduce the overall size of the detection device is a hot issue being studied by those skilled in the art. The embodiments of the present application provide an optical module, a laser radar and a terminal to reduce the volume of the detection device without reducing the detection performance of the detection device. The solution of the present application is introduced below.

[0114] Please refer to Figure 3, which is a schematic diagram of an optical module provided in an embodiment of the present application. The optical module 30 includes a transmitting port 301, a receiving port 302, a beam processing module 303 and a beam expansion module 304.

[0115] The number of transmitting ports 301 can be one or more. When the number of transmitting ports is one, one transmitting port can emit one transmitting light beam (or called an transmitting light beam of one channel). When the number of transmitting ports is multiple, multiple transmitting ports can respectively emit light beams to form multiple transmitting light beams (or called transmitting light beams of multiple channels). For ease of explanation, this application takes an optical module comprising N transmitting ports as an example for explanation, where N is an integer greater than or equal to 1. It is understandable that N transmitting light beams can be emitted through the N transmitting ports. Similarly, the number of receiving ports 302 is also set to N for ease of explanation. The N receiving ports are used to receive the return light beams of the N transmitting light beams. Exemplarily, the N receiving ports are used to receive N return light beams, wherein each receiving port is used to receive one return light beam.

[0116] It should be understood that the total number of transmitting ports (or receiving ports) in the optical module 30 may be greater than N. For example, if the optical module includes 30 transmitting ports, but 10 of them are currently in operation, then 10 (i.e., N=10) channels of transmitting light beams may be transmitted through the 10 transmitting ports.

[0117] The beam processing module 303 is used to process the light beam. This processing includes propagation and changes to the characteristics of the light beam during propagation. Propagation can include one or more of the following propagation processes: transmission, refraction, or reflection. Changes to the characteristics of the light beam can include one or more of the following: changing the optical path of the light beam (e.g., deflection, reflection, etc.), changing the polarization direction of the light contained in the emitted light beam, changing the wavelength distribution (e.g., filtering), etc.

[0118] Exemplarily, the beam processing module 303 is used to transmit N transmitted beams to the beam expansion module 304, and to propagate N return beams from the beam expansion module 304 to the N receiving ports 302. Furthermore, the beam processing module 303 can propagate the N return beams to the N receiving ports along an optical path different from that of the N transmitted beams (i.e., perform beam folding).

[0119] As can be seen from FIG3 , the N return beams here are the return beams of the N emission beams, and the N emission beams passing through the beam processing module 303 and the N return beams from the beam expansion module 304 are coaxial beams. It should be noted that the coaxial beams here mean that the N emission beams and the N return beams can pass through a common optical element. Moreover, under ideal circumstances, the main optical axes of the N emission beams passing through the beam processing module 303 and the N return beams from the beam expansion module 304 should be collinear. However, in the actual implementation process, due to errors in the manufacturing process, the rotation of the scanning mechanism, and even the movement of the optical module 30, the main optical axes of the two may not be completely collinear. However, the N emission beams and the N return beams can pass through the common beam expansion module 304 and other optical elements (described below), so the two are coaxial beams.

[0120] Beam expansion module 304 is used to expand N transmitted light beams. As shown in Figure 1, taking one transmitted light beam as an example, before passing through beam expansion module 304, the diameter of the transmitted light beam is represented as d1. After passing through beam expansion module 304, the diameter of the transmitted light beam is represented as d2, where d2>d1. Furthermore, because the optical path is reversible, once the transmitted light beam is expanded by beam expansion module 304, the return light beam can be contracted after passing through beam expansion module 304 in the reverse direction of the transmitted light beam.

[0121] As can be seen from Figure 3, the present application proposes an optical module comprising a two-stage optical system. The beam processing module 303 is a first-stage optical system, and the beam expansion module 304 is a second-stage optical system. The first-stage optical system is used to achieve the coaxiality of the emitted light beam and the return light beam, and to deflect the return light beam so that the return light beam can be received by the receiving port. The second-stage optical system is used to amplify the emitted light beam (i.e., expand the beam), thereby increasing the diameter of the emitted light beam to meet the requirements of light output collimation and receiving aperture. Furthermore, since the optical path is reversible, the emitted light beam is expanded by the beam expansion module, and the return light beam can be contracted after passing through the beam expansion module in the reverse direction of the optical path of the emitted light beam.

[0122] On the one hand, since the diameters of the emitted light beam before passing through the beam expansion module 304 and the return light beam after passing through the beam expansion module 304 are relatively small, the size of the light beam processing module 303 can also be designed to be relatively small, thereby reducing the overall volume of the light beam module. Moreover, when the size of the light beam is relatively small, the process tolerance angle of the optical elements for achieving coaxiality is also relatively high, and the engineering implementation is less difficult. On the other hand, the aperture of the second-stage optical system is relatively large, which can meet the needs of large-diameter light emission and light collection, and ensure detection performance. Moreover, since the first-stage optical system has achieved coaxial transmission and reception, the emitted light beam and the return light beam can share the same set of second-stage optical systems, which can further reduce the overall volume of the optical module. In summary, when the optical module is applied to a detection device, the overall size of the detection device can be significantly reduced, thereby reducing costs.

[0123] The transmitting port and receiving port in the embodiment of the present application are introduced below.

[0124] In some possible implementations, the emission port can be implemented by multiple waveguides or optical amplifiers. In some solutions, the emission port is implemented by a coupler provided on a waveguide chip, such as an edge coupler or a grating coupler. In some other solutions, the emission port can be implemented by the light output port (or light output end face) of the optical amplifier. An optical amplifier is a device that amplifies signal light, including but not limited to semiconductor amplifiers or optical fiber amplifiers. Among them, the semiconductor optical amplifier (SOA) uses semiconductor materials as gain media, which can amplify the power of signal light without significantly reducing its optical indicators. Alternatively, the emission port can also include multiple laser emitters, which can generate emission light beams.

[0125] In some possible implementations, the receiving port may be a receiving port of a waveguide, and an exemplary receiving port may be implemented by a coupler disposed on a waveguide chip. Alternatively, the receiving port may be an end facet for receiving light from a plurality of detection elements, and the detection elements may be photodiodes (PDs) capable of detecting light energy, such as InGaAs PDs, InP PDs, or Germanium PDs.

[0126] In one possible implementation, N transmit ports and N receive ports can be integrated into the same module. In some implementations, the N transmit ports and N receive ports are implemented using modules capable of propagating light beams, such as fiber arrays or waveguides. Hereinafter, modules integrating waveguides (or optical fibers) will be described using the term "waveguide chip." This term is for illustrative purposes only and does not limit the module's structure.

[0127] Optionally, the N transmitting ports and the N receiving ports can be located on the same end face. Please refer to Figure 4A, which is a schematic diagram of a waveguide chip provided in an embodiment of the present application. N (taking N=2 as an example) transmitting ports 301 and N receiving ports 302 can be set on an end face of the waveguide chip 40. Among them, the arrangement direction of the N receiving ports 302 is along the first direction (i.e., the y direction shown in Figure 4A). Furthermore, the N transmitting ports and the N receiving ports are all arranged along the y direction. As shown in Figure 4A, the N transmitting ports 301 and the N receiving ports 302 are all arranged along the y direction. Among them, the y direction is a direction illustrated for the convenience of explaining this solution. The remaining x directions, z directions, etc. can refer to the coordinate system shown in Figure 4A. They are all examples and are not intended to limit this solution. Please refer to Figure 4B, which is a schematic diagram of the optical path design of a waveguide chip provided in an embodiment of the present application. The waveguide chip 40 can receive the light beam of an FMCW laser and divide it into a transmitter (Tx) beam and an LO beam. The transmit beam is split and amplified (implemented by an SOA) inside the waveguide before being emitted. The transmit port 301 is implemented through the light output port of the SOA. The waveguide chip is also provided with a receive port. The receive (Rx) beam received by the receive port can be mixed with the LO in a mixer. The mixed signal is used as the input of the detection element (such as PD) in the detector array and is received by the detector element to process and obtain relevant information about the target in the object space.

[0128] Alternatively, the N transmit ports and the N receive ports can be located on different end faces of the same module. Referring to Figure 5 , which is a schematic diagram of another waveguide chip provided in an embodiment of the present application, the N transmit ports 301 can be located on the left end face, while the N receive ports 302 are located on the front face of the waveguide chip 40. When N > 1, the N receive ports 302 are arranged along the x-direction.

[0129] In another possible implementation, the N transmit ports and the N receive ports can be integrated into different modules. Taking the example of N transmit ports and N receive ports being located on different waveguide chips, FIG6 is a schematic diagram of another optical platform provided by an embodiment of the present application. As shown in FIG6 , the N transmit ports 301 can be located on a first waveguide chip 401, and the N receive ports can be located on a second waveguide chip 402. Furthermore, when N>1, the N receive ports 302 are arranged along the y-direction.

[0130] The following describes the beam processing module 303 in the optical module shown in Figure 3. In the aforementioned solution, the beam processing module 303 can achieve coaxial transmission and reception. In a specific implementation, the beam processing module 303 can include optical elements such as a PBS, a circulator, and a semi-transparent and semi-reflective beam splitter for achieving coaxial transmission.

[0131] Among them, the semi-transparent and semi-reflective beam splitter can split a beam of light into two beams of light with roughly the same spectral components, for example, within a certain wavelength region, such as the wavelength range of 300nm to 100μm, it has the same (the same here does not necessarily mean completely the same, and can fluctuate within a certain range) transmittance and reflectance for each wavelength. Generally speaking, neutral beam splitters with transmitted light and reflected light accounting for 50% each are more commonly used, but this application is also applicable to beam splitters with other transmission ratios (reflection ratios), such as a beam splitter with 40% transmission and 60% reflection. At this time, after the N emitted light beams pass through the semi-transparent and semi-reflective beam splitter, each emitted light beam is partially reflected and partially transmitted, resulting in energy loss in the N emitted light beams propagating to the beam expansion module 304. Similarly, the N return light beams from the beam expansion module are also partially emitted and partially transmitted after passing through the semi-transparent and semi-reflective mirror, resulting in a certain energy loss in the N return light beams.

[0132] A circulator is a multi-port device that transmits the incident wave entering any port to the next port in the order determined by the static bias magnetic field. Its outstanding feature is the unidirectional transmission of energy and the control of electromagnetic waves to be transmitted along a certain circular direction. For example, a circulator has three ports, and the light beam goes from port 1 to port 2, from port 2 to port 3, and from port 3 to port 1. The other paths are blocked, that is, it is impossible to go from port 2 to port 1 (that is, it has high isolation). At this time, N transmitted light beams can enter from port 1 and exit from port 2. The exiting light beams can continue to propagate to reach the beam expansion module, and N return light beams from the beam expansion module can enter from port 2 and exit from port 3, thereby achieving coaxial transmission and reception and reducing light beam loss.

[0133] A polarization beam splitter (PBS) is used to split a beam of light into two orthogonal linearly polarized beams: horizontal and vertical polarization, and then separate them into two different propagation directions, usually perpendicular to each other. For example, a PBS can split an incident light beam into P-polarized light and S-polarized light, with the polarization directions of the P-polarized light and the S-polarized light being perpendicular to each other.

[0134] Since the PBS splits light based on the polarization direction of light, combining the PBS with an element that can change the polarization direction of the light beam (such as a wave plate) can achieve coaxial transmission and reception. Consider a possible scenario: if the polarization direction of the N transmitted light beams entering the PBS is the same as that of P-polarized light, then the N transmitted light beams will pass through the PBS. At this time, by placing an optical element that can change the polarization direction between the PBS and the beam expansion module, the polarization direction of the N return light beams entering the PBS can be adjusted to be the same as that of S-polarized light, so that the N return light beams are reflected by the PBS. In short, by combining the PBS with an element that can change the polarization direction of the light beam, coaxial transmission and reception can be achieved, and the loss of the echo signal can be reduced.

[0135] Please refer to Figure 7, which is a schematic diagram of another optical module provided in an embodiment of the present application. In the optical module 30 shown in Figure 7, the beam processing module 303 includes a PBS 3031 and a QWP 3032. Among them, the light beam entering the PBS from the transmitting port may include a signal with a polarization direction of a first polarization direction. After passing through the PBS 3031 and the QWP 3032, it can reach the beam expansion module 304 and be further transmitted to the object space. The light beam from the object space again passes through the beam expansion module 304 to reach the QWP 3032. The polarization direction of the light beam that has passed through the QWP 3032 twice is perpendicular to the polarization direction of the light beam that has passed through the PBS 3031. Therefore, when passing through the PBS, it will be emitted through other optical paths to reach the receiving port 302, and will not propagate in the reverse direction of the original transmitted light beam. In addition, in Figure 7, the transmitting port and the receiving port are integrated in different modules.

[0136] Furthermore, the beam processing module 303 can also include more components to further process the beam. As shown in Figure 7, the beam processing module 303 also includes an HWP 3033, which is arranged on the optical path between the PBS 3031 and the N receiving ports 302. In this way, the beam processing module 303 includes a PBS 3031, a QWP (i.e., a quarter wave plate) 3032, and an HWP (i.e., a half wave plate) 3033. The N transmitted beams incident on the PBS are linearly polarized light. After passing through the PBS 3031 and the QWP 3032, the N emitted reflected beams are circularly polarized light. The circularly polarized light irradiates the target surface in the object space. After being reflected by the target, the N return beams obtained pass through the QWP 3032 again. At this time, the polarization direction of the N return beams is perpendicular to the polarization direction of the N transmitted beams incident on the PNS. Therefore, after passing through QWP 3032, the N reflected beams are reflected by PBS 3031 and then passed through HWP wave plate 3033. The polarization directions of the N return beams are rotated 90° again, thus aligning with the polarization directions of the N transmitted beams that entered the PBS. This facilitates the integration of polarization-maintaining waveguides, further reducing return beam loss and improving the effectiveness of the received return beams, thereby enhancing detection performance.

[0137] Please refer to Figure 8, which is a schematic diagram of another optical module provided in an embodiment of the present application. The light beam processing module includes a PBS3031, a QWP3032 and a folding mirror 3034, wherein most of the modules can be referred to the relevant description of Figure 7, and the folding mirror 3034 can fold the return light beam emitted from the PBS, so that its propagation direction is changed so that it propagates to the receiving port 302. At this time, the transmitting port and the receiving port can be integrated in the same module (such as in the waveguide chip 40). Of course, at this time, the transmitting port and the receiving port may not be integrated in the same module. For example, the first waveguide chip 401 and the second waveguide chip 402 shown in Figure 6 can replace the waveguide chip 40 in Figure 8. Optionally, the folding mirror 3034 can be realized by a reflector, or by coating a prism with a reflective film.

[0138] It should be understood that an HWP can also be provided in the structure shown in FIG8 , for example, between the PBS 3031 and the folding mirror 3034. Alternatively, in the aforementioned embodiment, the QWP can be replaced by two eighth-wave plates. Alternatively, the QWP can be replaced by one QWP plus one HWP.

[0139] The following introduces the beam expansion module 304 in the optical module shown in Figure 3. The beam expansion module 304 can be implemented by a telescope beam expansion system. Exemplarily, the beam expansion module includes a front lens group and a rear lens group, and the rear lens group refers to the lens that is closer to the object space on the optical path. Among them, the front lens group and the rear lens group can be implemented by a single lens, respectively, or by a lens group, respectively, or partially by a single lens and partially by a combination of lenses. Furthermore, the front lens group and the rear lens group are connected by a focal plane, and the focal plane here can be a real focal plane or a virtual focal plane. Exemplarily, the front lens group and the rear lens group respectively include a front focal plane and a rear focal plane, and the rear focal plane refers to the focal plane that is closer to the object space on the optical path. In some schemes, the front lens group is used to converge the incident light beam onto the rear focal plane of the front lens group, and the rear lens group re-collimates the light beam on the front focal plane of the rear lens group. For example, the focal length of the front lens group is f1, the focal length of the rear lens group is f2, and the beam expansion ratio of the beam expansion module 304 can be expressed as: N = f2 / f1. In some embodiments, the detection device requires the diameter of the output light spot to be d2. In this case, the diameter d1 of the emitted light beam passing through the beam processing module must satisfy: d1 = d2 / N.

[0140] Please refer to Figure 9, which is a schematic diagram of two beam expansion modules provided in an embodiment of the present application. In part (a) of Figure 9, the first lens group 3401 is implemented by a single lens, and the second lens group 3402 is also implemented by a single lens. The first lens group 3401 and the second lens group 3402 have a common focal plane 901. Optionally, the common focal plane 901 between the two can be a real focal plane or a virtual focal plane. The focal length of the first lens group 3401 can be smaller than the focal length of the second lens group 3402. In part (b) of Figure 9, the first lens group 3401 is implemented by multiple lenses, and the second lens group 3402 is also implemented by a single lens. The focal length of each lens in the first lens group 3401 is smaller than the focal length of the second lens group 3402, and the first lens group 3401 and the second lens group 3402 have a common focal plane 902. Optionally, the common focal plane 902 between the two can be a real focal plane or a virtual focal plane. As can be seen from FIG9 , the diameter of the emitted light beam can be enlarged by the beam expansion system, thereby meeting the requirements of large-diameter light emission and light collection and ensuring detection performance.

[0141] Optionally, the N emission light beams incident on the first lens group 3401 may be convergent light beams (described below).

[0142] In another possible embodiment, the optical module 30 may also include a scanning module. The scanning module is used to scan the N emission light beams that have passed through the beam expansion module to the object space, and to propagate the return light beams of the N emission light beams from the object space to the beam expansion module. The "scanning to the object space" here means that the N emission light beams are propagated to the object space at different angles through movement. Specifically, the scanning method of the scanning module can be one-dimensional or two-dimensional, and the present application does not limit the scanning method, the device for realizing scanning, etc. For example, the scanning device can realize one-dimensional or two-dimensional scanning by means of a swing mirror, a rotating mirror (Polygon), a micro-electro-mechanical system (MEMS) galvanometer, a metal galvanometer, and the like.

[0143] Please refer to FIG. 10 , which is a schematic diagram of the structure of another optical module provided in an embodiment of the present application. The optical module 30 shown in FIG. 10 may include a scanning module (or scanner) 305. The scanning module 305 can be movable to form multiple angles, thereby propagating N transmitted light beams into the object space at different angles. Of course, the return light beam also propagates through the scanning module to the beam expansion module.

[0144] Optionally, when N = 1, the scanning direction of the scanning module can have a variety of possible designs. As shown in Figure 10, the active axis of the scanning module can be perpendicular to the Z axis, such as active axis 1 shown in Figure 10. In this case, the scanning direction is perpendicular to the active axis, that is, it rotates or swings around the active axis. Alternatively, its active axis can be parallel to the Z axis, such as active axis 2 shown in Figure 10. It should be noted that when the scanning module performs 2D scanning, the aforementioned scanning direction can be the fast axis direction of the scanning module.

[0145] Optionally, when N>1, since the N emission light beams form multiple channels in the arrangement direction, the scanning direction of the scanning module 305 is usually not parallel to the arrangement direction of the N light beams. Please refer to Figure 11, which is a structural schematic diagram of another optical module provided in an embodiment of the present application. Taking N=2 as an example, the emission light beams of the two channels are arranged along the y direction, and the plane of light beam propagation is parallel to the XY plane. At this time, the movable axis of the scanning module 305 is usually perpendicular to the z direction, and the scanning module swings or rotates around the z axis. Exemplarily, the scanning direction of the scanning module is perpendicular to the arrangement direction of the N emission light beams. For example, when multiple channels are arranged horizontally (that is, multiple channels are arranged in at least one row), the scanning module needs to move vertically so that multiple channels scan the object space in the form of "row scanning".

[0146] In the optical module 30 including the scanning module 305, if the scanning module is inactive (or in a stationary state), the principal optical axes of the N return beams after passing through the scanning module 305 are parallel or even collinear with the principal optical axes of the N transmitted beams before passing through the scanning module 305. These N return beams can be referred to as ideal return beams. However, when the scanning module is operating normally, the scanning module has moved at an angle such that the N return beams no longer propagate in the direction of the ideal return beams (i.e., parallel to the direction of the N transmitted beams), but instead have a certain deviation angle, i.e., a walkoff angle. It is not difficult to see that the angular direction of the walkoff angle is the same as the scanning direction of the scanning module. Because the area in which a receiving port can receive light (referred to as the effective receiving area) is limited, especially for receiving ports with relatively small pattern areas and small light apertures, such as optical fibers and waveguides, the walkoff angle of the beam can seriously affect the loss of the return beam during the receiving process.

[0147] Please refer to Figure 12, which is a schematic diagram of a walk-off angle provided in an embodiment of the present application. Taking N=1 as an example, the scanning direction of the scanner is the y direction (perpendicular to the z-axis direction and the direction in which the emitted light beam enters the scanning module 305). Since the scanner is continuously scanning, there is a walk-off angle γ between the N return light beams and the ideal return light beam. When the scanner moves, the first angle is greater than 0° and less than 90°, that is, 0°<γ<90°. The existence of the walk-off angle γ causes the optical path of the N return light beams and the ideal return light beam (indicated by the dotted line) to be offset, and the direction of the offset is the y direction. In some schemes, the offset caused by the walk-off angle of the N return light beams can be compensated by offsetting the position of the receiving port compared to the spot position of the ideal return light beam. In conjunction with Figure 12, the spot of the ideal receiving light beam reaching the waveguide chip 40 is represented by area 1101. The position of receiving port 302 is offset from area 1101, for example, by Δy in the y direction. This can compensate for the offset of the N return beams, allowing the light spot of the first return beam to be closer to the effective receiving area of ​​receiving port 302, or even coincide with the center of the effective receiving area of ​​receiving port 302. In this way, receiving port 302 can more accurately receive the first return beam, improving the effectiveness of the received echo signal and enhancing detection performance.

[0148] In some scenarios, because the scanning direction is different from the arrangement direction of the N light beams, the direction of the walk-off angle is also different from the arrangement direction of the N return light beams. Please refer to Figure 13 for another schematic diagram of the walk-off angle provided by an embodiment of the present application. In Figure 13, multiple emission ports can emit light beams of multiple channels. Taking N = 2 and the scanning direction of the scanner in the z direction as an example, due to the continuous scanning of the scanner, there is a walk-off angle γ between the N return light beams and the ideal return light beam. The walk-off angle γ indicates the offset of the N return light beams from the ideal return light beam in the z direction. However, the arrangement direction of the N light beams is along the y direction. Therefore, the direction of the walk-off angle is inconsistent with the arrangement direction of the N light beams, and may even be perpendicular (i.e., the walk-off direction is in the z direction). When N return light beams propagate to N receiving ports, if the receiving port 302 is set at the spot position where the ideal return light beam arrives at the receiving port, the existence of the walk-off angle causes the spot position of the N light beams when they arrive at the receiving port 302 to be offset from the spot position when the ideal return light beam arrives at the receiving port 302, and when the walk-off angle is in the z direction, the two are offset by Δz in the z direction. At this time, the spot of the return light beam cannot be accurately received by the receiving port 302, resulting in a large amount of loss of the light beam received by the receiving port, which seriously affects the accuracy of the detection. Furthermore, the angle of the walk-off angle is positively correlated with the detection distance and the scanning speed of the scanning module. It can be understood that when the target in the object space is farther away from the beam module, the angle of the walk-off angle is larger, and vice versa, the walk-off angle is smaller.

[0149] In some solutions, the position of the receiving port can be offset in the z direction to compensate for the light spot offset caused by the walk-off angle and reduce the signal loss caused by the walk-off angle.

[0150] However, in some cases, when N receiving ports are arranged along a first direction, it may be difficult to implement these N receiving ports with offsets in other directions (especially the thickness direction), i.e., offsets in the z-direction. Consequently, the offset caused by the walk-off angle cannot be compensated, resulting in high light beam loss during reception and impacting detection performance. As a possible implementation, the optical module 30 may further include a spot transposition mechanism that can adjust the walk-off angles of the N return light beams to be aligned with the arrangement direction of the N light beams. An optical module including a spot transposition mechanism is described below with reference to FIG. 14 and other figures.

[0151] Please refer to Figure 14, which is a structural schematic diagram of another optical module provided by the present application. The optical module 30 may include a spot transfer mechanism 306, which is used to convert the walk-off angle direction of each of the N return light beams into the arrangement direction of the N return light beams. As shown in Figure 14, before passing through the spot transfer mechanism 306, the existence of the walk-off angle γ causes the N return light beams to be offset from the ideal return light beam in the z direction. After passing through the spot transfer mechanism 306, the direction of the walk-off angle of the N return light beams is converted to the arrangement direction of the N light beams. After the direction of the walk-off angle is adjusted to the arrangement direction of the N return light beams, the angular offset of the N return light beams caused by the walk-off angle can be compensated by misaligning them in the arrangement direction of the N receiving ports, which can help reduce the signal loss caused by the walk-off angle and improve the effectiveness of the signal.

[0152] Please refer to Figure 15, which is a schematic diagram of the effect of a spot transposition provided by an embodiment of the present application. The return beams of the multiple channels are arranged along the first axis, and the scanner scans along the second axis. The departure direction of the return beam is consistent with the scanning direction of the scanner. Therefore, the departure direction of the return beam will be inconsistent with the arrangement direction of the multiple channels, or even perpendicular to each other. As shown in Figure 15, the solid circle is used to represent the spot of the return beam, and the dotted circle is used to represent the spot of the return beam under ideal conditions (or the spot of the emission beam on the coaxial optical path). The return beam contains 4 channels, respectively represented as CH1 to CH4. The arrangement direction of the return beams of the 4 channels is along the y-axis direction, and the departure direction is along the z-axis direction, so the departure direction is along the z-axis direction. After the spot transposition, the arrangement direction of the return beam is still along the y-axis direction, but the spot of each channel is rotated by a certain angle, so that the departure direction of the return beam is also along the y-axis direction, that is, the departure direction of the return beam is consistent with the arrangement direction of the multiple channels.

[0153] In some solutions, the receiving ports are implemented using waveguides or optical fibers. For example, in the case of N receiving ports implemented using N waveguides, the arrangement direction of the N return beams aligns with the arrangement direction of the N waveguides. Referring to FIG14 , since the N receiving ports are also arranged along the y-axis, offsetting the N receiving ports along the y-axis during design is convenient in waveguide technology. This allows for offsetting the arrangement direction of the N receiving ports 302 to compensate for beam loss caused by walk-off angles, which helps reduce signal loss caused by the walk-off angle and improves signal effectiveness. For related descriptions, please refer to the description of offsetting the receiving ports 302 in the related description of FIG12 .

[0154] It should be understood that the structure shown in FIG14 can also be implemented in a single-channel case, and the specific situations are not described here one by one.

[0155] The spot transposition mechanism and its effects have been mentioned above. The following provides an exemplary description of possible implementations of the spot transposition mechanism. The spot transposition mechanism 306 may include one or more stepped reflectors. The stepped reflector includes N reflective surfaces arranged in a stepped manner. One stepped design approach may include: N reflective surfaces are arranged sequentially in one direction and spaced apart in another direction, thereby forming a step. Each reflective surface is used to reflect one of the N return beams and can also be used to reflect one of the N transmitted beams.

[0156] Please refer to Figure 16A, which is a structural schematic diagram of a stepped reflector provided in an embodiment of the present application. The first stepped reflector 3061 includes four reflecting surfaces, which are respectively represented as reflecting surface A1B1C1D1, reflecting surface A3B3C3D3, reflecting surface A4B4C4D4, etc. Among them, reflecting surface A1B1C1D1 is used to reflect a returning light beam. In conjunction with Figure 16A, it can be seen that the four reflecting surfaces are arranged in sequence along the y direction (i.e., the arrangement direction of the light beams), the four first reflecting surfaces are arranged at a certain distance along the x direction (i.e., the propagation direction of N light beams), and the positions of the four reflecting surfaces in the z direction are the same. Taking the optical path of the returning light beam as an example, when the walk-off angle of the returning light beam is in the z direction, the walk-off angle direction is rotated 90 degrees after passing through the stepped reflector, i.e., along the x direction.

[0157] Optionally, in FIG16A , the reflective surface of the stepped reflector intersects the beam plane formed by the N returning received light beams (i.e., the plane formed by the propagation direction and the arrangement direction), and further, the two are neither parallel nor perpendicular. Furthermore, the bottom surface of the reflective surface of the stepped reflector is at a 45° angle, or the reflective surface of the stepped reflector is at a 45° angle to the beam plane of the ideal received light beam (i.e., the XY plane). In this case, the N reflective surfaces of the stepped reflector are mutually parallel.

[0158] Optionally, the N reflecting surfaces may be non-parallel. Exemplarily, the reflecting surface in the step reflector intersects with the beam plane formed by the N returning receiving light beams (i.e., the plane formed by the propagation direction and the arrangement direction), and the angle between the reflecting surface and the bottom surface increases from the center of the step to the edge of the step. In other words, the reflecting surfaces of multiple steps are deflected inward relative to the center of the step so that the multiple reflecting surfaces are inwardly gathered. Please refer to Figure 16B, which is a structural schematic diagram of another step reflector provided in an embodiment of the present application. Taking N=4 as an example, the angle between the reflecting surface A1B1C1D1, the reflecting surface A2B2C2D2, the reflecting surface A3B3C3D3, and the reflecting surface A4B4C4D4 in the first step reflector 3061 and the bottom surface, i.e., the XY plane of Figure 16B, gradually increases from the center of the step to the edge of the step. In other words, the angle between the reflecting surface A1B1C1D1 and the bottom surface is greater than the angle between the reflecting surface A2B2C2D2 and the bottom surface, and the angle between the reflecting surface A4B4C4D4 and the bottom surface is greater than the angle between the reflecting surface A3B3C3D3 and the bottom surface.

[0159] The angles between the multiple reflecting surfaces and the bottom surface are all greater than or equal to 45°. In some schemes, the N non-parallel reflecting surfaces can be regarded as four reflecting surfaces that originally had an angle of 45° with the bottom surface, and are rotated along the rotation axis to the center of the step at the following angles α1, α2, α3, and α4. The rotation axis is an axis that is 45° to the beam plane of the ideal received light beam (i.e., the XY plane). Further optionally, the angle of rotation gradually increases from the inside of the step to the outside of the step center. For example, α1, α2, α3, and α4 can be 9°, 3°, 3°, and 9°, respectively. There may be other designs during the specific implementation process. It should be noted that this is for the purpose of understanding the design and implementation of the reflecting surface. Therefore, the state of the reflecting surface is described by rotating, which does not mean that the reflecting surface can be rotated during use. The step reflector shown in Figure 16B can change the pointing angles of the multiple light beams passing through, and the four parallel incident light beams will be converged after passing through the step reflector.

[0160] It should be understood that the design of the N reflecting surfaces shown in Figure 16B is only an example, and other designs may be used in some schemes. For example, please refer to Figure 16C, which is a structural schematic diagram of another step reflector provided in an embodiment of the present application. The N non-parallel reflecting surfaces are regarded as four reflecting surfaces that originally have an angle of 45° with the bottom surface, and are rotated to the outside of the step along the rotation axis at the following angles α4, α5, α6, and α7. Among them, the rotation axis is an axis that is 45° to the beam plane (i.e., the XY plane) of the ideal received light beam. Further optionally, the angle of rotation gradually increases from the inside of the step to the outside of the step center. The step reflector shown in Figure 16C can change the pointing angles of the multiple light beams passing through, and the four parallel incident light beams will be diverged after passing through the step reflector.

[0161] In some possible implementations, the spot transfer mechanism may include a stepped reflector and a folding mirror. When the optical module 30 includes a PBS 3031 and a beam expander module 304, the spot device structure may be located between the beam expander module 304 and the PBS 3031. The front lens group of the beam expander module (e.g., the first lens group 3041) includes a stepped microlens array (i.e., multiple lenses), wherein the TX port, the reflective surface of the stepped reflector, and the microlenses correspond one-to-one. Furthermore, the TX port, the reflective surface of the stepped reflector, the microlenses, and the RX port also correspond one-to-one.

[0162] In some further possible implementations, the light spot transfer mechanism may include a plurality of stepped reflectors, and the plurality of stepped reflectors may be arranged relative to each other, thereby rotating the direction of the walk-off angle twice.

[0163] Please refer to Figure 17A, which is a structural schematic diagram of another light spot transposition mechanism provided in an embodiment of the present application. The light spot transposition mechanism 306 includes two groups of stepped reflectors arranged opposite to each other, which are conveniently distinguished as first stepped reflectors 3061 and second stepped reflectors 3062. Each group of stepped reflectors includes multiple reflective surfaces arranged in a stepped manner, and one reflective surface can be used to deflect a return light beam. The first stepped reflector 3061 includes four first reflective surfaces, such as first reflective surface A1B1C1D1, first reflective surface A3B3C3D3, first reflective surface A4B4C4D4, etc. The four first reflective surfaces are arranged in sequence along the y-axis direction (i.e., the arrangement direction of the return light beam) and are arranged at a certain interval in the x-direction (i.e., the propagation direction of the return light beam). One first reflective surface is used to deflect one return light beam. The second stepped reflector 3062 includes four second reflective surfaces, such as second reflective surface E1F1G1H1, second reflective surface E3F3G3H3, and second reflective surface E4F4G4H4. These four second reflective surfaces are arranged sequentially along the x-direction (i.e., the propagation direction of the return beam passing through the first stepped reflector 3061) and spaced apart in the y-direction (i.e., the arrangement direction of the return beam passing through the first stepped reflector 3061). Each second reflective surface is used to deflect one return beam.

[0164] As can be seen in conjunction with FIG17A , each first reflective surface in the first stepped reflector 3061 is used to fold one of the N return beams and propagate it to one of the N second reflective surfaces. Each of the N second reflective surfaces is used to fold one of the N return beams so that the walk-off angles of the N return beams are aligned with the arrangement direction of the N return beams. In conjunction with FIG16B , after passing through the spot transposition mechanism 306 , the walk-off angles of the beams are transposed to the x-direction. At this point, the N return beams are also aligned along the x-direction, and the beam offset caused by the walk-off angles is also an x-direction offset Δx.

[0165] In some possible implementations, the spot transfer mechanism 306 is further configured to adjust the pointing angles of the N light beams passing through. For example, the spot transfer mechanism 306 may adjust the pointing angles of the N transmitted light beams and / or the N received light beams passing through. Exemplarily, the spot transfer mechanism 306 includes one or more stepped reflectors as shown in FIG16B or FIG16C.

[0166] Please refer to Figure 17B, which is a schematic diagram of the structure of another light spot transposition mechanism provided in an embodiment of the present application, wherein the angle of the first group of 1*4 stepped reflectors 3601 is 45°, while the angle of the second group of 1*4 stepped reflectors 3601 is such that at least one surface has an angle that is different from the angles of the other reflective surfaces. For example, the angles of the 1*4 stepped reflectors are all deflected inward, and the deflection angle increases from the center of the step to the outside. For example, the two outermost reflective surfaces are deflected by 9°, while the inner reflective surface is deflected by 3°, thereby achieving different pointing directions of the light beam.

[0167] In some possible embodiments, a stepped reflector, such as the first stepped reflector 3061 shown in Figures 16A, 16B, and 16C, and the first stepped reflector 3061 and the second stepped reflector 3062 shown in Figures 17A and 17B, includes a substrate and N reflectors, wherein the N reflectors are attached to the substrate, and each reflector is used to provide a reflective surface. Exemplarily, the first stepped reflector 3061 includes a first substrate and N first reflectors, wherein the N first reflectors are attached to the first substrate, and each first reflector includes a first reflective surface. The second stepped reflector includes a second substrate and N second reflectors, wherein the N second reflectors are attached to the second substrate, and each second reflector includes a second reflective surface.

[0168] In some possible implementations, the light spot transposition mechanism is a prism, and the N first reflective surfaces and N second reflective surfaces are achieved by coating the prism with a reflective film. Please refer to Figure 17C, which is a schematic structural diagram of another light spot transposition mechanism provided in an embodiment of the present application. The light spot transposition mechanism 306 is a prism that includes multiple reflective surfaces achieved by coating, such as four first reflective surfaces and four second reflective surfaces. The positional relationship between the reflective surfaces can be seen in the relevant description of Figure 17A.

[0169] In some possible implementations, the position of the spot transfer mechanism can be designed in a variety of ways; the position shown in Figure 14 is merely an example. For example, the spot transfer mechanism can also be positioned on the optical path of the return beam after it passes through the PBS, that is, between the PBS and the receiving port. For another example, if the beam expansion module includes a first lens group and a second lens group, the spot transfer mechanism can also be positioned between the first and second lens groups.

[0170] The following describes the components included in the optical module provided in the embodiments of the present application. In some possible embodiments, the optical module 30 further includes a transmitting lens group and a receiving lens group. The transmitting lens group is disposed between the N transmitting ports and the beam processing module, and the receiving lens group is disposed between the N receiving ports and the beam processing module. Furthermore, the transmitting lens group and / or the receiving lens group may also be included in the beam processing module.

[0171] Optionally, the emission lens group may include one or more lenses. For example, when there are multiple emission ports, the emission lens group may be implemented using multiple lenses, with each lens corresponding to a single emission port. In some embodiments, the emission lens group may be a microlens array. Furthermore, for example, a single lens may correspond to at least one of the multiple emission ports. For example, a single lens may be used to collimate light beams emitted from N emission ports.

[0172] Similarly, the transmitting lens group can include one or more lenses. For example, when there are multiple receiving ports, the receiving lens group can be implemented using multiple lenses, with each lens corresponding to a receiving port. In some embodiments, the receiving lens group can be a microlens array. Furthermore, for example, a lens can correspond to at least one of the multiple receiving ports. For example, a single lens can be used to collimate the light beams emitted by N receiving ports.

[0173] The following is an illustrative description of the packaging design of the optical module in the embodiments of this application. In some possible implementations, the transmitting port, transmitting lens assembly, receiving port, receiving lens assembly, and beam processing module are packaged as a first optical assembly, and the beam expansion module is packaged as a second optical assembly. The first and second optical assemblies are provided with light-transmitting windows for passing N transmitted light beams and N return light beams.

[0174] Optionally, the transmitting lens group, receiving lens group, and beam processing module can be packaged as a transceiver module. Referring to Figure 18, which is a schematic diagram of the structure of a transceiver module provided in an embodiment of the present application, the transceiver module 180 can include a transmitting lens group 307, a receiving lens group 308, a PBS 3031, a QWP 3032, an HWP 3033, and a folding mirror 3034. In this way, coaxial and collimated transmission and reception can be achieved through an integrated lens and prism combination, further reducing the overall size of the detection device.

[0175] As a possible implementation, the first optical component includes a transmitting port, a receiving port, and a transceiver module, wherein the transmitting port and the receiving port can be replaced by a waveguide chip including the transmitting port and the receiving port.

[0176] Alternatively, the transmitting lens group, receiving lens group, beam processing module, and front group of the beam expansion module can be packaged as a transceiver module. As shown in Figure 18, the transceiver module can optionally include the first lens group 3041 in the beam expansion module 304. As another possible implementation, the first optical assembly includes a transmitting port, a receiving port, and the transceiver module. The rear group of the beam expansion module is packaged as a second optical assembly.

[0177] A variety of possible solutions have been mentioned above, and some possible designs of this solution will be further described below in conjunction with Figures 19 to 24. It should be understood that the various possible designs and possible implementations shown in this application can be combined.

[0178] Please refer to Figure 19, which is a structural schematic diagram of another optical module provided in an embodiment of the present application. Among them, the transmitting port and the receiving port are arranged on a waveguide (WG) chip, that is, the waveguide port (WGport) includes a transmitting (TX) port and a receiving (RX) port. As shown in Figure 19, the transmitting port and the receiving port are both arranged on the right side of the waveguide chip. The beam processing module includes a PBS, a QWP, a HWP and a folding mirror, and optionally also includes a transmitting lens group (TX lens) and a receiving lens group (RX lens). The beam expansion module includes two groups of lenses, front and back, and the front lens group and the rear lens group are connected by a focal plane P1.

[0179] During transmission, the light beam emitted from the transmitting port passes through the TX lens, PBS, QWP, and beam expander module before reaching the scanner, where it is scanned into the object space. The return beam from the object space passes through the scanner, beam expander module, QWP, PBS, HWP, deflecting mirror, and RX lens before reaching the receiving port. The return beam from a near-range target is reflected and converges at position 1. Since the return beam from a distant target has a longer flight time and a larger walk-off angle, the return beam from the distant target converges at position 2. Furthermore, the span between positions 1 and 2 corresponds to the waveguide's mode spot size along the walk-off direction.

[0180] In some possible designs, the components in the optical module can be packaged to further improve the integration and stability of the device. Among them, the waveguide chip, TX lens, RX lens, PBS polarization beam splitter assembly (including PBS elements, QWP, HWP), and folding mirror can be packaged as a first optical component, or called a first-stage optical system, that is, the IO package (IO package) shown in Figure 19. The front lens group and the rear lens group in the beam expansion system are packaged as a whole to form a second optical component, or called a second-stage optical system. There is a window between the first-stage optical system and the second-stage optical system that can let light pass (such as by setting a window piece). At this time, since the first-stage system contains a waveguide chip and small-sized optical components, it is easier to perform tube and shell packaging and achieve a better thermal expansion coefficient (CTE) matching design, thereby improving integration and stability. The second-stage system can be regarded as a beam expansion lens group and is installed as a whole between the first-stage optical system, improving the overall stability of the optical module and being able to decouple from the first-stage optical system.

[0181] In a two-stage optical system package, during transmission, light enters the second optical system from the first optical system. The second optical system further expands the beam to meet the design requirements before exiting the second optical system of the optical module. During reception, light enters the second optical system. The beam expander module is used to reduce the received beam. The return beam, after being reduced by the beam expander module, passes through the optical window and enters the first optical system. After passing through the PBS component, deflecting mirror, and RX lens in the first optical system, it is coupled into the waveguide chip.

[0182] Please refer to Figure 20, which is a structural schematic diagram of another optical module provided in an embodiment of the present application. The difference from Figure 19 is that the port of the waveguide chip includes multiple transmitting ports and multiple receiving ports, and the optical module includes a spot transposition mechanism. Since the port of the waveguide chip includes multiple transmitting ports and multiple receiving ports, the transmitted light beam and the return light beam are both multi-channel light beams. In conjunction with Figure 20, the multiple channels are arranged along the first axis, and the scanner scans along the second axis. The walk-off direction is consistent with the scanning direction of the scanner, so the walk-off direction is inconsistent with the arrangement direction of the multiple channels. Due to the limitations of the waveguide process, the walk-off direction needs to be transposed to the waveguide arrangement direction, and the walk-off direction can be adjusted to be consistent with the arrangement direction of the multiple channels through the spot transposition mechanism, as shown in Figure 20. Optionally, the spot transposition mechanism is also used to change the direction of the multiple light beams passing through, so that the multi-channel emission light beams enter the beam expansion system after convergence.

[0183] In a possible optical path design, taking an optical module comprising 4 transmitting ports and 4 receiving ports as an example, after the 4 transmitting light beams emitted by the 4 transmitting ports emerge from the optical module, the angle between adjacent light beams is 1.2° (that is, the pointing angles are 1.8°, 0.6°, -0.6° and -1.8° respectively). The interval between the four transmitting ports is exemplarily 2.2mm, the focal length of the TX lens is exemplarily 0.5mm, the focal length of the RX lens is exemplarily 2.5mm, and the center distance between two adjacent reflecting surfaces of the step reflector is exemplarily 2.2mm. The front lens group of the beam expansion module is a 1*4 microlens array to achieve beam convergence, and the rear lens group is a collimating lens to achieve beam expansion and pointing. The focal length of the front lens group is exemplarily 6.8mm, and the focal length of the rear collimating lens group is exemplarily 68mm, thereby achieving a beam expansion ratio of 1:10. In this optical path design, the size of each optical element and the distance between the light beams can be at the millimeter level, which significantly reduces the overall volume of the detection device.

[0184] Please refer to Figure 21, which is a schematic diagram of the structure of another optical module provided in an embodiment of the present application. The difference from Figure 18 is that the waveguide port includes multiple transmitting ports and multiple receiving ports, and the optical module includes a spot transposition mechanism. The difference from Figure 19 is that the front lens group (i.e., the lens closest to the PBS) in the beam expansion system can include multiple lenses, and the spot transposition mechanism does not need to change the direction of the multiple light beams passing through.

[0185] In some possible implementations, in conjunction with FIG21 , the spot transposition mechanism may include a set of stepped reflectors, and the front group of the beam expansion module may be a set of stepped microlens arrays. The TX port, the reflective surface in the stepped reflector, and the microlenses in the microlens array correspond one to one. Furthermore, the three correspond one to one to the RX port. A transmitting light beam emitted from a TX port is incident on a reflective surface of the stepped reflector, and after reflection, enters a lens in the microlens array. Correspondingly, a return light beam passes through a lens in the microlens array, enters a reflective surface of the stepped reflector, and is received by an RX port through the PBS.

[0186] In some other possible implementations, the light spot transposition mechanism may include two stepped reflectors, one of which is shown in FIG16B . In a possible optical path design, taking an optical module including four transmitting ports and four receiving ports as an example, after the four transmitting light beams emitted by the four transmitting ports exit the optical module, the angle between adjacent light beams is 1.2° (i.e., the pointing angles are 1.8°, 0.6°, -0.6°, and -1.8°, respectively). The spacing between the four transmitting ports is exemplarily 2.2 mm, the focal length of the TX lens is exemplarily 1 mm, the focal length of the RX lens is exemplarily 5 mm, and the center-to-center spacing between two adjacent reflecting surfaces of the stepped reflector is exemplarily 2.2 mm. The first set of 1x4 stepped mirrors in the spot transposition mechanism have four faces with a 45° angle to the bottom, while the second set of 1x4 stepped mirrors have four faces with a 45° angle to the bottom. Simultaneously, they are rotated ±3° and ±9° relative to the movable axis shown in Figure 16B. This allows the N emitted light beams from the beam module to be arranged into a linear array. This optical path design allows the size of each optical component and the distance between beams to be in the millimeter range, significantly reducing the overall size of the detection device.

[0187] Please refer to Figure 22, which is a schematic diagram of the emission light path of another optical module provided in an embodiment of the present application. The difference from Figures 19-21 is that the spot transposition mechanism is located within the beam expansion module, and the front lens group in the beam expansion module is a microlens array. The microlens array can include multiple microlenses arranged in a stepped manner to focus the passing light beam. The spot transposition mechanism can be used to adjust the walk-off of the return beam, and the rear lens group can increase the aperture of the emitted beam, improving detection performance.

[0188] Among them, the light spot transfer mechanism may include one or more stepped reflectors for realizing the rotation of the walk-off angle. For detailed description, please refer to the relevant descriptions of the aforementioned Figures 16A, 16B, 16C, 17A and 17B.

[0189] The above describes some solutions of the present application using a coaxial architecture as an example. The following introduces an optical module using an off-axis architecture provided in an embodiment of the present application.

[0190] Please refer to Figure 23, which is a structural schematic diagram of an optical module adopting an off-axis architecture provided in an embodiment of the present application. The optical module 230 includes a beam transceiver module 2301 and a light spot transfer mechanism 306, wherein the beam transceiver module 2301 includes N transmitting ports 301 and N receiving ports 302, and the N transmitting ports 301 and the N receiving ports 302 are cross-arranged along the end face of the beam transceiver module.

[0191] The N transmitting ports are used to transmit N transmitting light beams, and the N receiving ports are used to receive N return light beams, where the N return light beams are return beams of the N transmitting light beams. A spot transposition mechanism 306 is disposed in the optical path of the N transmitting light beams and the N return light beams. The N transmitting light beams after passing through the spot transposition mechanism are used to scan the object space in a second direction. The N return light beams before passing through the spot transposition mechanism have a walk-off angle in the second direction. The N return light beams are arranged along a first direction, which is different from the first direction.

[0192] The spot transposition mechanism is used to fold the walk-off angle of each of the N return beams to align with the arrangement of the N return beams and provide them to the N receiving ports. For details on the design of the spot transposition mechanism, see the aforementioned descriptions, such as those in Figures 16A, 16B, 16C, 17A, and 17B.

[0193] In one possible implementation, the optical module 30 further includes a beam expansion module 304, which is used to expand the N transmitted light beams and shrink the N return light beams. Further, the design of the beam expansion module 2303 can be found in the above description.

[0194] 23 , the beam expander module may include a first lens group 3041 and a second lens group 3042, which have a common focal plane 901. The first lens group 3041 may include multiple lenses, which may be arranged in a stepped or parallel arrangement.

[0195] Optionally, in the structure shown in FIG23 , the light spot transposition mechanism may include one or more stepped reflectors as shown in FIG16A , configured to deflect the walk-off angle of each of the N return beams to be aligned with the arrangement direction of the N return beams. For related descriptions, see the descriptions of FIG16A and FIG17A .

[0196] Optionally, in conjunction with Figure 23, the optical module 30 may further include a scanning module, which is arranged on the optical path of the end of the light spot transfer mechanism away from the emission port.

[0197] Please refer to Figure 24, which is a schematic diagram of the structure of another optical module using an off-axis architecture provided in an embodiment of the present application. In it, N transmitting ports 301 and N receiving ports 302 are arranged crosswise, that is, the port next to a transmitting port is a receiving port. The N transmitting ports 301 can emit N transmitting light beams, each of which passes through a spot transposition mechanism 306 (optionally passing through a beam expansion module) to reach a scanner 305, and the N return light beams from the scanner 305 follow a path opposite to the transmitting light beam, pass through the spot transposition mechanism to reach the N receiving ports.

[0198] After passing through the spot transposition mechanism 306, the walk-off directions of the N return beams are transposed to the arrangement direction of the N return beams, which is conducive to offsetting the arrangement direction of the receiving port to achieve walk-off compensation, thereby reducing the loss of the return beam and improving the detection performance.

[0199] The present application also provides a laser radar, which includes the aforementioned optical module. Furthermore, the laser radar also includes a light source, such as a laser. Optionally, the frequency of the light beam emitted by the light source can be continuously variable, such as a frequency modulated continuous wave (FMCW) laser.

[0200] Furthermore, the laser radar also includes a detector for obtaining an electrical signal based on the light beam. For example, the detector may include a photodiode (PD) capable of detecting light energy, such as an InGaAs PD, an InP PD, or a germanium PD.

[0201] The embodiment of the present application further provides a terminal, which includes the aforementioned optical module. Alternatively, the terminal includes the aforementioned laser radar.

[0202] Optionally, the terminal can be an intelligent terminal or transportation tool such as a vehicle, a drone, or a robot. Of course, the terminal can also be replaced by industrial equipment, entertainment and leisure equipment, etc. Intelligent terminals include mobile phones, tablet computers, laptops, smart bracelets, smart watches, or smart glasses. Transportation tools include vehicles, ships, aircraft, or logistics robots. Industrial equipment includes industrial robots and robotic arms. Leisure and entertainment equipment includes virtual reality (VR) equipment, mixed reality (MR) equipment, massage chairs, or 4D cinema cabins. This application does not impose strict restrictions on the devices to which the electrical connector can be applied.

[0203] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, a conflicting connection or an integrated connection. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0204] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described in this application as "exemplary" or "for example" should not be construed as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0205] The “at least one” mentioned in the embodiments of this application refers to one or more, and “plurality” refers to two or more. “At least one of the following items” or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, at least one of a, b, or c can represent: a, b, c, (a and b), (a and c), (b and c), or (a and b and c), where a, b, c can be single or multiple. “And / or” describes the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character “ / ” generally indicates that the previous and next associated objects are in an “or” relationship.

[0206] Furthermore, unless otherwise specified, ordinal numbers such as "first" and "second" used in the embodiments of this application are used to distinguish multiple objects and are not used to define the order, timing, priority, or importance of multiple objects. For example, the first reflective surface and the second reflective surface are only used to facilitate the description of the reflective surfaces and do not indicate differences in structure, importance, etc. between the first reflective surface and the second reflective surface.

Claims

DEPCT691. The optical module consists of N transmitting ports, N receiving ports, a beam processing module, and a beam expansion module, where N is an integer greater than or equal to 1; the N transmitting ports are configured to send N output beams; the N receiving ports are configured to receive beams reflected from N output beams; the beam processing module is configured to: send N output beams to the beam expansion module, deflect N reflected beams from the beam expansion module, and pass N deflected beams to the N receiving ports, where the N reflected beams are reflected from N output beams, and the N output beams that passed through the beam processing module and the N reflected beams from the beam expansion module are coaxial beams; and the beam expansion module is configured to expand the beam on N output beams.The optical module under claim 1, where the beam processing module consists of a polarizing optical splitter PBS, a quarter-wave plate QWP, and a reflector, where the QWP is placed on the optical path between PBS and the beam expansion module, and the reflector is placed on the optical path between PBS and the receiving port N, where N transmitted beams are sent to the beam expansion module through PBS and QWP, and N reflected beams from the beam expansion module are sent to the reflector through QWP and PBS, and the reflector is configured to deflect the beams passing through PBS and send the deflected beams to the receiving port N.

3. The optical module under claim 2, where PBS is configured to transmit the beam in the first polarization direction and reflect the beam in the second polarization direction, where the first polarization direction is perpendicular to the second polarization direction, and the QWP is configured to change the polarization of the beams passing through QWP and the polarization direction of the beams after N transmitted beams pass through QWP, so that they are perpendicular to the polarization direction of the N transmitted beams. 4.An optical module under one of claims 1 through 3, whereby the optical module also contains a scanning module, and the scanning module is configured to: scan N transmitted beams passing through the beam amplification module into the object area and transmit N transmitted beams from the object area to the beam amplification module.

5. An optical module under claim 4, where N is greater than or equal to 2 and N reflected beams after passing through the scanning module are aligned in the first direction, the scanning direction of the scanning module is the second direction, the deviation angle direction of each reflected beam from N beams is the second direction, and the second direction is different from the first direction. The optical module also contains a spot orientation mechanism, and the spot orientation mechanism is positioned on the optical path between the scanning module and N receiving ports, and the spot orientation mechanism is configured to change the deviation angle direction of each reflected beam from N beams to the alignment direction of N reflected beams. 6.The optical module under claim 5, where the spot redirection mechanism consists of a first stepped reflector and a second stepped reflector, where the first stepped reflector consists of N first-level reflective surfaces arranged in a stepped manner, and the second stepped reflector consists of N second-level reflective surfaces arranged in a stepped manner, with N first-level reflective surfaces opposite N second-level reflective surfaces one by one, and the second stepped reflector is configured to further reflect the light emitted from the first stepped reflector.

7. The optical module under claim 6, where each of the N first-level reflective surfaces is configured to redirect one of N reflected beams and transmit the redirected reflected beam to one of the N second-level reflective surfaces, and each of the N second-level reflective surfaces is configured to redirect one of N reflected beams so that the deflection angle direction of the reflected beams is the same as the alignment direction of all N reflected beams. 8.

9. An optical module according to claim 6 or 7 where the total angle between the bottom surface of the first stepped reflector and the first N reflective surfaces is 45 degrees, and the total angle between the bottom surface of the second stepped reflector and the second N reflective surfaces is 45 degrees.

10. An optical module according to claim 6 to 7 where the total angle between the bottom surface of the first stepped reflector and the first N reflective surfaces is 45 degrees, and the total angle between the bottom surface of the second stepped reflector and the second N reflective surfaces gradually increases from the center of the steps of the second stepped reflector to the two sides of the second stepped reflector.

11. An optical module according to one of claims 6 through 9 where the light spot redirection mechanism is a prism and the first N reflective surfaces and the second N reflective surfaces are created by coating reflective films in the prism.

11. An optical module according to one of claims 6 through 9 where the first stepped reflector consists of the first support surface and N first reflectors, N first reflectors are attached to the first support surface, and each first reflector consists of one first reflective surface; and the second stepped reflector consists of the second support surface and N second reflectors, N second reflectors are attached to the second support surface, and each second reflector consists of one first reflective surface.

12. An optical module according to one of claims 6 through 11 where the beam-expanding module consists of the first group of lenses and the second group of lenses, and the first and second groups of lenses share a common focal plane.

13. An optical module according to claim 12 where the spot redirection mechanism is placed between the first and second groups of lenses.

14. An optical module according to claim 12 or 13 where the first group of lenses consists of N lenses, and each of the N lenses is configured to transmit one of N reflected beams. 15.An optical module as described in one of the claims 1 to 14, whereby the optical module also comprises a transmitting lens group and a receiving lens group, where the transmitting lens group is positioned between the beam amplification module and N transmitting ports, and the receiving lens group is positioned between the beam amplification module and N receiving ports and N transmitting ports. The transmitting lens group, N receiving ports, the receiving lens group, and the beam processing component are integrated into the first optical assembly. The beam amplification module is integrated into the second optical assembly. A translucent window is placed on the first and second optical assemblies, and the translucent window is configured to transmit N transmitted beams and N reflected beams.

16. An optical module as described in one of the claims 1 to 15, whereby the N transmitting ports and N receiving ports are the waveguiding ports of the waveguiding chip. 17.The optical module consists of a beam transmitting / receiving module and a beam directing mechanism. The transmitting / receiving module has N transmitting ports and N receiving ports, where the transmitting and receiving ports are arranged alternately along one cross-section of the module, and N is an integer greater than 1. The transmitting port N is configured to transmit N passed beams, and the receiving port N is configured to receive N reflected beams, where the reflected beams are reflected from the N transmitted beams. The beam directing mechanism is positioned along the optical paths of the N transmitted beams and the N reflected beams. After passing through the beam directing mechanism, the N transmitted beams are used to scan the object area, where the scanning direction is the second direction. The deflection angle of the N reflected beams before passing through the light spot directing mechanism is the second direction. The N reflected beams are arranged in the first direction, and the second direction is different from the first. The light spot directing mechanism is configured to: change the deflection angle of each N reflected beam to the alignment direction of the N reflected beams and provide N reflected beams to the N receiving ports.

19. An optical module under claim 17 where the spot redirection mechanism consists of a first stepped reflector and a second stepped reflector where the first stepped reflector consists of N first-level reflective surfaces arranged in a stepped manner, and the first stepped reflector consists of N second-level reflective surfaces arranged in a stepped manner, where N first-level reflective surfaces are opposite N second-level reflective surfaces one at a time, and the second stepped reflector is configured to reflect additional light emitted from the first group of stepped reflectors.

20. A lidar where the lidar consists of an optical module under any of claims 1 through 16, or consists of an optical module under claim 17 or 18.

20. A terminal where the terminal consists of an optical module under any of claims 1 through 16, or consists of an optical module under claim 17 or 18, or consists of a lidar under claim 19.

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