WO2024078364A1 - Laser radar - Google Patents

Abstract

A laser radar, comprising a laser light source (100), a beam splitter mixer (200), an optical transceiver (300), a total reflector (400), a first photoelectric detector (500) and a substrate (310), wherein the beam splitter mixer (200), the optical transceiver (300) and the first photoelectric detector (500) are all integrated on the substrate (310); and the beam splitter mixer (200) is configured to receive a laser beam emitted by the laser light source (100) and split the laser beam into two beams, one of which is output through a second port to the optical transceiver (300) to serve as a detection beam, and the other is output through a third port to the total reflector (400) to serve as a local oscillation beam, and is further configured to receive an echo optical signal from the optical transceiver (300) and the local oscillation beam reflected by the total reflector (400), mix the echo optical signal and the reflected local oscillation beam to obtain a beat-frequency optical signal, and then output the beat-frequency optical signal to the first photoelectric detector (500). In this way, the laser radar has a high degree of integration.

Description

LiDAR

This application claims priority to the Chinese patent application filed with the State Intellectual Property Office on October 11, 2022, with application number 202211240436.9 and invention name “Lidar”, all contents of which are incorporated by reference in this application.

Technical Field

The present application relates to the field of laser radar technology, and in particular to a laser radar.

Background technique

Existing laser radar systems usually require a narrow linewidth light source, and a beam splitter is arranged on the optical path of the light source, as shown in Figure 1. The light emitted by the laser light source 100 is divided into detection light and local oscillator light after passing through the beam splitter 101. The detection light can be transmitted to a silicon photonic chip (such as an optical phased array (OPA) chip, etc.) or other optical components, and the silicon photonic chip or other optical components then transmit the detection light to the target to be detected 103, and the target to be detected 103 receives the detection light and reflects it to form an echo light signal. The radar system receives the above-mentioned echo light signal, and performs frequency mixing processing, data analysis and other operations on the local oscillator light and the echo light signal through the mixer 102, and finally obtains the parameters such as the direction, distance, and volume of the target to be detected.

In the prior art, the beam splitting function and mixing function of the laser radar are respectively realized by a beam splitter and a mixer. The beam splitter and the mixer are respectively arranged on different optical paths in the system, resulting in a large number of optical devices in the radar system and introducing additional light loss, which leads to a decrease in the signal-to-noise ratio. In addition, since each optical device requires a corresponding arrangement space, the entire radar system has a low degree of integration and a large size.

technical problem

One of the purposes of the embodiments of the present application is to provide a laser radar.

Technical Solutions

The technical solution adopted in the embodiment of the present application is:

Provided is a laser radar, comprising a laser light source, a beam splitting mixer, an optical transceiver, a total reflector, a first photodetector and a substrate, wherein the beam splitting mixer, the optical transceiver and the first photodetector are all integrated on the substrate;

The beam splitting mixer has a first port, a second port, a third port and a fourth port, and the first port, the second port, the third port and the fourth port are respectively connected to the laser light source, the optical transceiver, the total reflector and the first photodetector through an optical path;

The beam splitting mixer is used to receive the laser beam emitted by the laser light source and split the laser beam into two beams, one of which is output to the optical transceiver through the second port for use as a detection beam, and the other is output to the total reflector through the third port for use as a local oscillator beam; the beam splitting mixer is also used to receive an echo light signal from the optical transceiver and a local oscillator light beam reflected by the total reflector, and mix the echo light signal and the reflected local oscillator light beam to obtain a beat frequency light signal, and then output the beat frequency light signal to the first photodetector.

In one embodiment, the beam splitting mixer is a fiber optic component, a spatial optical path structure or a multi-port coupler.

In one embodiment, the beam splitting mixer is a 2 by 2 coupler.

In one embodiment, the optical transceiver is a coaxial optical transceiver.

In one embodiment, the laser radar further includes an optical phase shifter, which is located between the total reflector and the third port of the beam splitter mixer and is used to adjust the phase of the local oscillator light beam between the total reflector and the beam splitter mixer.

In one embodiment, the laser radar further includes an optical amplifier, which is located between the beam splitting mixer and the optical transceiver and is used to amplify the detection light beam.

In one embodiment, the optical amplifier is a fiber amplifier or a semiconductor optical amplifier.

In one embodiment, the laser radar further includes an optical circulator and a second photodetector, wherein a first port of the optical circulator is connected to the laser light source, a second port of the optical circulator is connected to a first port of the beam splitting mixer, and a third port of the optical circulator is connected to the second photodetector;

Part of the beat frequency optical signal is output to the first photodetector through the fourth port, and another part of the beat frequency optical signal is output to the second photodetector through the third port and the optical circulator.

In one embodiment, at least one of the first photodetector and the second photodetector is integrated on the substrate.

In one embodiment, the second photodetector and the first photodetector form a balanced detector.

In one embodiment, the laser radar further includes a coupler formed on the substrate, wherein the coupler is optically connected to the beam splitting mixer and the laser light source respectively, and is used to couple the laser beam provided by the laser light source to the beam splitting mixer.

In one embodiment, the coupler is connected to the laser light source optical path via an optical fiber or a spatial optical path.

In one embodiment, the laser light source is a narrow line width light source, and its line width is less than 1 MHz.

In one embodiment, the laser radar further includes a collimating and converging device, the collimating and converging device is located on the first side of the optical transceiver, and the collimating and converging device is used to collimate the detection light beam and converge the echo light signal;

The first side is the side where the optical transceiver emits the detection light beam and receives the echo light signal.

Beneficial Effects

The beneficial effect of the laser radar provided by the embodiment of the present application is that the laser radar provided by the embodiment of the present application includes a laser light source, a beam splitting mixer, an optical transceiver, a total reflector, a first photodetector and a substrate. On the one hand, the laser radar provided by the embodiment of the present application integrates the beam splitting function and the mixing function into the beam splitting & mixing multiplexing structure (i.e., the beam splitting mixer) to form a separate object, so that the light splitting and mixing involved in the laser radar system can be completed in an integrated device, without the need to separately arrange the beam splitter and the mixer on the optical path of the system, thereby increasing the integration of the entire laser radar and reducing the volume of the laser radar; on the other hand, the beam splitting mixer, the optical transceiver and the first photodetector are all integrated on the substrate to form a silicon photonic chip, thereby increasing the integration of the entire radar system and reducing the volume of the system, while realizing on-chip mixing and on-chip reception of echo optical signal light, reducing the loss of the beat frequency optical signal and the echo optical signal light, and also avoiding the interference of the end face reflected light on the echo optical signal light when the optical transceiver adopts a coaxial transceiver system, thereby improving the detection sensitivity of the radar.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or exemplary technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 is a schematic diagram of the structure of a laser radar in the prior art, in which the dotted arrows represent the end face reflected light;

FIG2 is a schematic diagram of the structure of a laser radar provided in an embodiment of the present application;

FIG3 is a schematic diagram of the structure of a beam splitting mixer used in an embodiment of the present application;

FIG4 is a schematic diagram of the structure of a beam splitting mixer used in another embodiment of the present application;

FIG5 is a schematic diagram of the structure of a beam splitting mixer used in another embodiment of the present application;

FIG6 is a schematic diagram of the structure of a laser radar provided in another embodiment of the present application;

FIG7 is a schematic diagram of the structure of a laser radar provided in another embodiment of the present application;

FIG8 is a schematic diagram of the structure of a laser radar provided in another embodiment of the present application;

FIG9 is a schematic structural diagram of an assembly of an optical transceiver and a beam splitting mixer used in an embodiment of the present application;

FIG. 10 is a schematic structural diagram of an assembly of an optical transceiver and a beam splitting mixer used in another embodiment of the present application.

Description of reference numerals:

100, laser light source; 101, beam splitter; 102, mixer; 103, target to be detected; 200, beam splitting mixer; 300, optical transceiver; 310, substrate; 320, collimating and converging device; 330, coupler; 400, total reflector; 500, first photodetector; 600, optical phase shifter; 700, optical circulator; 800, second photodetector; 900, optical amplifier.

Embodiments of the present invention

In order to make the purpose, technical solution and advantages of the present application more clearly understood, the present application is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

It should be noted that when a component is referred to as being "fixed on" or "disposed on" another component, it may be directly on the other component or indirectly on the other component. When a component is referred to as being "connected to" another component, it may be directly or indirectly connected to the other component. The orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances. The terms "first" and "second" are only used for the purpose of convenience of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features. The meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

In order to illustrate the technical solution provided by the present application, a detailed description is given below in conjunction with specific drawings and embodiments.

As shown in FIG1 , in the prior art, a laser radar generally includes a laser light source 100, a beam splitter 101, a mixer 102, an optical circulator 700, a silicon photonic chip, and a first photodetector 500. The silicon photonic chip can be in various forms. For example, the silicon photonic chip may include a substrate 310 and an optical transceiver 300 integrated on the substrate 310; or a structure as shown in FIG1 may be used, including a substrate 310 and an optical transceiver 300 integrated on the substrate 310 and a coupler 330. Of course, in other embodiments, the silicon photonic chip may also adopt other structures, which are not limited here. However, regardless of the specific structure of the silicon photonic chip, there is generally no circulator on it. Therefore, after receiving the reverse propagating echo light signal, it is usually necessary to first couple the echo light signal to the outside of the silicon photonic chip, and then pass through the optical circulator 700 of the optical fiber to transmit the echo light signal to the mixer 102. The echo light signal received by the silicon photonic chip through coupling is usually very weak, and the echo light signal will be further attenuated when coupled out of the optical transceiver through the port, which greatly reduces the detection sensitivity of the laser radar. In addition, there is generally strong end face reflection light at the end face where the existing silicon photonic chip and the optical fiber are coupled (as shown by the dotted arrow in Figure 1). Since the intensity of the end face reflection light is usually greater than the intensity of the echo light signal, when the optical transceiver uses a coaxial optical transceiver, the echo light signal will be "submerged" in the end face reflection light and cannot be identified.

In order to solve the optical loss caused by the above phenomenon, as well as the technical problems of low integration and large volume of the radar system, the embodiment of the present application provides a laser radar. As shown in FIG2 , the laser radar includes a laser light source 100 , a beam splitting mixer 200 , an optical transceiver 300 , a total reflector 400 , a first photodetector 500 and a substrate 310 .

Among them, the beam splitting mixer 200, the optical transceiver 300 and the first photodetector 500 are all integrated on the substrate 310 to form a silicon photonic chip. Generally, the optical transceiver 300 can adopt a parallel axis transceiver system or a coaxial transceiver system, which can be flexibly selected according to the needs of use, and is not limited here. In this embodiment, in order to obtain a better beat frequency optical signal, the splitting ratio of the beam splitting mixer 200 can be 1:1, or any other unequal splitting ratio, which can be selected according to actual needs.

The beam splitter mixer 200 has a first port, a second port, a third port and a fourth port. Specifically, the beam splitter mixer 200 in this embodiment has a bidirectional transmission function, two of the four ports are input ports, and the other two ports are output ports, and their functions can be interchanged. The first port, the second port, the third port and the fourth port are respectively connected to the laser light source 100, the optical transceiver 300, the total reflector 400 and the first photodetector 500 through optical paths.

In this embodiment, the laser light source 100 is used to provide a laser beam. The beam splitting mixer 200 is used to receive the laser beam emitted by the laser light source 100, and split the laser beam into two beams, one of which is output to the optical transceiver 300 through the second port for use as a detection beam, and the other is output to the total reflector 400 through the third port for use as a local oscillator beam; the beam splitting mixer 200 is also used to receive the echo light signal from the optical transceiver 300 and the local oscillator beam reflected by the total reflector 400, and mix the echo light beam and the reflected local oscillator light beam to obtain a beat frequency light signal, and then transmit the beat frequency light signal to the first photodetector 500.

The working principle of the laser radar provided in the embodiment of the present application is as follows:

When detecting a target to be detected, the laser light source 100 emits a laser beam and couples it to the silicon photonic chip. The laser beam enters the beam splitter mixer 200 through the first port, and is then split into two beams by the beam splitter mixer 200, one of which is output as a detection beam to the optical transceiver 300 through the second port, and the other is output as a local oscillator beam to the total reflector 400 through the third port.

Afterwards, the detection beam is outputted by the optical transceiver 300 and irradiated onto the target 103 to be detected, and then reflected by the target 103 to be detected to form an echo optical signal, which is received by the optical transceiver 300 and then transmitted through it and enters the beam splitting mixer 200 through the second port. At the same time, the local oscillator beam is provided to the total reflector 400 through the third port, and then reflected by the total reflector 400 and returns to the beam splitting mixer 200 again through the third port. In the beam splitting mixer 200, the echo optical signal and the reflected local oscillator light beam are mixed to obtain a beat frequency optical signal; then the beat frequency optical signal is split by the beam splitting mixer 200, wherein a part of the beat frequency optical signal is output through the first port and is discarded or enters other components, and the other part of the beat frequency optical signal is transmitted to the first photodetector 500 through the fourth port, and then the first photodetector 500 converts the beat frequency optical signal into an electrical signal, and then the electrical signal is transmitted to an external digital processing device, which processes and analyzes the data and finally obtains the detection data (such as distance, speed, etc.) of the target 103 to be detected.

In the above process, the echo light signal received by the optical transceiver 300 is still relatively weak, but the echo light signal can be directly input into the beam splitting mixer 200 through the second port, and then directly input into the first photodetector 500 through its fourth port after being mixed by the beam splitting mixer 200. In this process, the echo light signal does not need to be coupled out of the silicon photonic chip by coupling as in the prior art, thereby greatly reducing the loss of the echo light signal in this process. In addition, since the mixing is performed in the silicon photonic chip in the above process, the end face reflected light when the optical transceiver 300 and the optical fiber are coupled will not be introduced. This can not only reduce the loss of the echo light signal, but also avoid the interference of the end face reflected light on the echo light signal, thereby achieving the purpose of improving the detection sensitivity of the laser radar.

The laser radar provided in the embodiment of the present application includes a laser light source 100, a beam splitter mixer 200, an optical transceiver 300, a total reflector 400, a first photodetector 500 and a substrate 310, wherein the beam splitter mixer 200 has a beam splitting function and a mixing function, and realizes the output and reception of light through multiple input ports and multiple output ports. Therefore, the light splitting and mixing involved in the laser radar system are completed in an integrated device, and there is no need to separately arrange the beam splitter 101 and the mixer 102 on the optical path of the system, thereby increasing the integration of the entire laser radar and reducing the volume of the system. At the same time, the design of the beam splitter mixer 200 with multiple input ports and multiple output ports is conducive to the arrangement of other components corresponding to the corresponding ports, and other components are arranged in an orderly manner around the beam splitter mixer 200, further increasing the integration of the entire laser radar.

In addition, in the laser radar provided in the embodiment of the present application, the beam splitting mixer 200, the optical transceiver 300 and the first photodetector 500 are all integrated on the substrate 310 to form a silicon photonic chip, which increases the integration of the entire radar system and reduces the system volume. At the same time, on-chip mixing and on-chip reception of echo optical signal light are realized, thereby reducing the loss of beat frequency optical signals and echo optical signal light. It can also avoid the interference of end face reflected light on the echo optical signal light when the optical transceiver adopts a coaxial transceiver system, thereby improving the detection sensitivity of the radar.

The above-mentioned beam splitting mixer 200 can be at least one of an optical fiber component, a spatial optical path structure, a multi-port coupler, etc., or a combination of multiple ones, as long as the above-mentioned functions can be achieved.

When the beam splitter mixer 200 is an optical fiber component, it can be a fused taper type optical fiber coupler formed by two optical fibers through a fused taper method, as shown in FIG3. During preparation, the coating of the two optical fibers is removed, and the two optical fibers are brought close together in a certain way, melted under high temperature heating, and stretched to both sides at the same time, forming a special waveguide structure in the form of a double cone in the heating area to achieve optical power coupling. Controlling the length of the stretched taper coupling area can control the power coupling ratio (splitting ratio) of the two ports. It can also be a four-port optical fiber coupler formed by splicing multiple optical fibers, as shown in FIG4.

When the beam splitting mixer 200 is a spatial optical path structure, as shown in FIG. 5 , a plurality of total reflection channels are connected to form a four-port optical path structure.

When the beam splitter mixer 200 is a multi-port coupler, a 2x2 coupler or an M×N star coupler can be used. The above coupler can be an optical fiber coupler, or a micro-optical element coupler, an integrated optical waveguide coupler or other types of couplers, as long as the above functions can be achieved.

In an optional embodiment, the beam splitting mixer 200 is a 2x2 coupler with a bidirectional conduction function. The laser light source 100 is connected to the first port of the 2x2 coupler through an optical fiber, the first photodetector 500 is connected to the fourth port of the 2x2 coupler through an optical fiber, the optical transceiver 300 is connected to the second port of the 2x2 coupler through an optical fiber, and the total reflector 400 is connected to the third port of the 2x2 coupler through an optical fiber. The beam splitting mixer 200 adopts a 2x2 coupler, which has a simple structure and is easy to install. In the specific laser radar structure, the beam splitting mixer can be an MMI coupler or a bidirectional directional coupler.

In other embodiments, the beam splitting mixer 200 may also be other multi-port couplers, such as a 3x3 coupler, a 2x3 coupler, a 3x2 coupler, etc., which may be flexibly selected according to usage requirements.

In the prior art, optical transceivers mostly use parallel axis transceiver systems, that is, the optical axes of the optical system for receiving and emitting detection light and the optical system for receiving and transmitting echo light in the optical transceiver are parallel to each other, so as to avoid the interference of optical crosstalk between the transceiver systems on the detection light signal. However, the two optical paths of the parallel axis transceiver system need to be strictly aligned with high precision, which is difficult. Therefore, in an optional embodiment, the optical transceiver uses a coaxial optical transceiver.

Specifically, the coaxial optical transceiver in this embodiment can be an optical phased array (OPA) or other optical components with coaxial transceiver function, which can be flexibly selected according to the needs of use, and no limitation is made here. The coaxial optical transceiver mentioned here refers to the coaxial arrangement of the optical system for receiving and emitting the detection light and the optical system for receiving and transmitting the echo light in the transceiver, and generally the above two optical systems are the same group of optical systems. At this time, the laser radar is a coaxial transceiver laser radar system, so that the echo light signal reflected back by the target to be detected can propagate back in the reverse direction of the emission direction of the detection light, so the detection light path and the echo light signal light path can be automatically aligned without adjustment. At the same time, the optical transceiver 300 adopts a coaxial optical transceiver, which is small in size and highly integrated, and helps to reduce the volume of the entire radar system.

In an optional embodiment, as shown in Fig. 6, the laser radar further includes an optical phase shifter 600. Specifically, the optical phase shifter 600 is located between the total reflector 400 and the third port of the beam splitter mixer 200, and is used to adjust the phase of the local oscillator light beam between the total reflector 400 and the beam splitter mixer 200, so as to obtain a better beat frequency light signal with the echo light signal.

In an optional embodiment, as shown in FIG7 , the laser radar further includes an optical amplifier 900. Specifically, the optical amplifier 900 in this embodiment may be an optical fiber amplifier, a semiconductor optical amplifier, etc., which may be selected according to the use requirements. For example, if the beam splitting mixer 200 and the optical transceiver 300 are integrated on the substrate 310, the optical amplifier 900 adopts a semiconductor optical amplifier; if the beam splitting mixer 200 and the optical transceiver 300 are arranged in an all-fiber link, the optical amplifier 900 adopts an optical fiber amplifier. The optical amplifier 900 is located between the beam splitting mixer 200 and the optical transceiver 300, and is used to amplify the detection beam, improve the optical power of the detection beam, and increase the ranging capability of the radar system.

When the laser radar provided by the above embodiments is used, the beat frequency optical signal generated by the beam splitting mixer 200 will be divided into two beams when output due to the beam splitting function of the beam splitting mixer 200, one of which is received and used by the first photodetector 500, but the other is usually directly abandoned, resulting in a waste of the echo optical signal. In addition, this part of the echo optical signal may also enter the laser light source 100 and cause adverse effects on its light output effect. To avoid the above problems, in an optional embodiment, as shown in FIG8, the laser radar also includes an optical circulator 700 and a second photodetector 800, the first port of the optical circulator 700 is connected to the laser light source 100, the second port of the optical circulator 700 is connected to the first port of the beam splitting mixer 200, and the third port of the optical circulator 700 is connected to the second photodetector 800.

The second photodetector 800 and the first photodetector 500 can be used as a balanced detector or separately. Specifically, when the second photodetector 800 and the first photodetector 500 are used as a balanced detector, the second photodetector 800 and the first photodetector 500 need to use two photodetectors with completely similar characteristics. By using a balanced detector, the signals obtained by the two photodetectors can be added together, so that the noise in the two paths is completely offset, the output amplitude is greatly amplified, and the detection sensitivity of the laser radar is improved.

When the laser radar provided in this embodiment is used for detection, the beat frequency optical signal formed by mixing by the beam splitting mixer 200 is divided into two parts by the beam splitting mixer 200, one part is output to the first photodetector 500 through the third port, and the other part is output to the second photodetector 800 through the optical circulator 700.

The laser radar provided in this embodiment is provided with an optical circulator 700. The input light from the laser light source 100 passes through the optical circulator 700 and then enters the first port of the beam splitter mixer 200 through the optical fiber; and the other part of the beat frequency optical signal after mixing from the beam splitter mixer 200 can be sent to the second photodetector 800 through the optical circulator 700, so that the beat frequency optical signal received by the first photodetector 500 and the second photodetector 800 can be used to obtain the data of the target 103 to be detected. At the same time, the other part of the beat frequency optical signal after mixing is obtained through the optical circulator 700, which effectively prevents the other part of the beat frequency optical signal from returning to the laser light source 100 through the first port, avoids the loss of the beat frequency optical signal, and the beat frequency optical signal interferes with the normal operation of the laser light source 100. In this way, the two parts of the beat frequency optical signal after mixing by the beam splitter mixer 200 are received and utilized, which can effectively improve the detection sensitivity of the laser radar.

The first photodetector 500 and the second photodetector 800 can both be separately arranged relative to the optical transceiver 300, and can also be integrated on a silicon photonic chip to further improve the integration of the entire radar system. Of course, according to the specific setting space and requirements, one of the first photodetector 500 and the second photodetector 800 can be separately arranged relative to the silicon photonic chip, and the other can be integrated on the silicon photonic chip.

In a specific embodiment, the first photodetector 500 and the second photodetector 800 are both integrated on the substrate 310 , which can reduce the size of the radar system and further increase the integration of the radar system.

In an optional embodiment, as shown in FIG9 , the laser radar further includes a coupler 330 formed on the substrate 310. Specifically, the coupler 330 is integrated on the silicon photonic chip, and the coupler 330 is optically connected to the beam splitting mixer 200 and the laser light source 100, respectively, for coupling the laser beam provided by the laser light source 100 to the beam splitting mixer 200. The structure provided in this embodiment is adopted, and compared with the beam splitting mixer 200, a coupling structure is additionally provided to connect with the laser light source 100, which can further improve the integration of the laser radar and reduce the volume of the laser radar.

In an optional embodiment, the coupler 330 can be optically connected to the laser light source 100 through an optical fiber or a constructed spatial optical path, which can be flexibly selected according to the installation space and usage requirements, and is not limited here. The coupler 330 adopts this structure, which is simple in structure and easy to install.

In an optional embodiment, the laser light source is a narrow line width light source, and its line width is less than 1 MHz. The laser light source adopts a narrow line width light source, which can make its own phase noise very low and the spectral purity very high, thereby making the detection performance of the laser radar better.

Since the light emitted by the laser light source generally has a certain divergence angle, the detection light beam emitted by the laser radar provided by the above embodiments also has a certain divergence angle, so that after the detection light irradiated on the target to be detected is reflected, a part of it will be reflected to the area outside the receiving range of the optical transceiver, resulting in an incomplete point cloud obtained by the laser radar, and the adverse effects of this phenomenon are reduced. In some embodiments, as shown in FIG10, the laser radar also includes a collimating and converging device 320 located on the first side of the optical transceiver 300. The first side is the side where the optical transceiver 300 emits the detection light beam and receives the echo light signal. The collimating and converging device 320 can be located outside the substrate or fixed on the surface of the substrate, and is used to collimate the detection light beam and converge the echo light signal. Specifically, when the collimating and converging device 320 is located outside the substrate, the collimating and converging device 320 can be composed of one or more lenses, and the lens can be a convex lens, a concave lens or a lens of other shapes, which can be determined according to the light emission effect, and is not limited here; other optical elements/structures that can achieve the above functions can also be used. When the collimating and converging device 320 is fixed on the surface of the substrate, a microlens array in an array form can be processed on the surface of the substrate by micromachining technology to form the collimating and converging device 320, or other optical elements capable of achieving the above functions can be used.

By using the laser radar provided in this embodiment, the detection beam can be collimated for output, and most of the detection light irradiated on the target 103 to be detected can be returned to the optical transceiver 300 along the preset path, thereby improving the detection performance of the laser radar. The preset path can be the same as the propagation path of the detection beam, or it can be a path parallel to the propagation path of the detection beam, depending on the type of the optical transceiver 300.

Of course, if the laser light source adopts a light source assembly with a collimating device, that is, the laser light source directly provides a collimated laser beam, the first side of the optical transceiver may not be provided with a collimating focusing device.

The above are only optional embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims (14)

A laser radar, characterized in that it comprises a laser light source (100), a beam splitting mixer (200), an optical transceiver (300), a total reflector (400), a first photodetector (500) and a substrate (310), wherein the beam splitting mixer (200), the optical transceiver (300) and the first photodetector (500) are all integrated on the substrate (310); The beam splitting mixer (200) has a first port, a second port, a third port and a fourth port, and the first port, the second port, the third port and the fourth port are respectively connected to the laser light source (100), the optical transceiver (300), the total reflector (400) and the first photodetector (500) through optical paths; The beam splitting mixer (200) is used to receive the laser beam emitted by the laser light source (100), and split the laser beam into two beams, one of which is output to the optical transceiver (300) through the second port to be used as a detection beam, and the other is output to the total reflector (400) through the third port to be used as a local oscillator beam; the beam splitting mixer (200) is also used to receive an echo light signal from the optical transceiver (300) and a local oscillator light beam reflected by the total reflector (400), and perform mixing processing on the echo light signal and the reflected local oscillator light beam to obtain a beat frequency light signal, and then output the beat frequency light signal to the first photodetector (500). The laser radar as described in claim 1 is characterized in that the beam splitting mixer (200) is an optical fiber component, a spatial optical path structure or a multi-port coupler. The laser radar as described in claim 1 or 2 is characterized in that the beam splitting mixer (200) is a 2 by 2 coupler. The laser radar as described in claim 1 is characterized in that the optical transceiver (300) is a coaxial optical transceiver (300). The laser radar as described in claim 1 is characterized in that the laser radar also includes an optical phase shifter (600), which is located between the total reflector (400) and the third port of the beam splitter mixer (200) and is used to adjust the phase of the local oscillator light beam between the total reflector (400) and the beam splitter mixer (200). The laser radar as described in claim 1 is characterized in that the laser radar also includes an optical amplifier (900), and the optical amplifier (900) is located between the beam splitting mixer (200) and the optical transceiver (300) for amplifying the detection light beam. The laser radar as described in claim 6 is characterized in that the optical amplifier (900) is a fiber optic amplifier or a semiconductor optical amplifier. The laser radar as claimed in claim 1, characterized in that the laser radar also includes an optical circulator (700) and a second photodetector (800), wherein a first port of the optical circulator (700) is connected to the laser light source (100), a second port of the optical circulator (700) is connected to a first port of the beam splitter mixer (200), and a third port of the optical circulator (700) is connected to the second photodetector (800); Part of the beat frequency optical signal is output to the first photodetector (500) via the fourth port, and another part of the beat frequency optical signal is output to the second photodetector (800) via the third port and the optical circulator (700). The laser radar as described in claim 8 is characterized in that at least one of the first photodetector (500) and the second photodetector (800) is integrated on the substrate (310). The laser radar as described in claim 8 is characterized in that the second photodetector (800) and the first photodetector (500) form a balanced detector. The laser radar as described in claim 1 is characterized in that the laser radar also includes a coupler formed on the substrate (310), and the coupler is optically connected to the beam splitting mixer (200) and the laser light source (100), respectively, for coupling the laser beam provided by the laser light source (100) to the beam splitting mixer (200). The laser radar as described in claim 11 is characterized in that the coupler is connected to the optical path of the laser light source (100) through an optical fiber or a spatial optical path. The laser radar as described in any one of claims 1-12 is characterized in that the laser light source (100) is a narrow linewidth light source, and its linewidth is less than 1 MHz. The laser radar according to any one of claims 1 to 12, characterized in that the laser radar further comprises a collimating and converging device (320), the collimating and converging device (320) being located on the first side of the optical transceiver (300), and the collimating and converging device (320) being used to collimate the detection light beam and converge the echo light signal; The first side is the side where the optical transceiver (300) emits the detection light beam and receives the echo light signal.