Optical transceiver module and laser radar

Abstract

The application discloses an optical transceiver module and a laser radar. The optical transceiver module comprises a first light splitting prism, a polarization light splitting prism, a second light splitting prism and a first reflecting unit. The first light splitting prism is used for receiving a first light beam and performing polarization light splitting to output a probe light and a local oscillator light. The polarization light splitting prism is used for receiving and outputting the probe light, and receiving a return light and outputting at least part of the return light. The second light splitting prism is used for receiving the return light, splitting the return light, receiving the local oscillator light and splitting the local oscillator light, so that part of the return light and part of the local oscillator light are mixed into a second light beam, and the remaining part of the return light and the remaining part of the local oscillator light are mixed into a third light beam, and the phases of the second light beam and the third light beam are 180 degrees different. The first reflecting unit is used for reflecting the local oscillator light to the second light splitting prism. The technical scheme of the application can reduce the energy loss of optical coupling, reduce power consumption and improve efficiency.

Description

Technical Field

[0001] This application relates to the field of lidar technology, and in particular to an optical transceiver module and lidar. Background Technology

[0002] In related technologies, frequency-modulated continuous wave (FMCW) lidar uses silicon photonics chips as optical transceiver modules. On one hand, it transmits and emits probe light via a transmitting waveguide to detect target objects; on the other hand, it receives and transmits echo light to a photodetector module via a receiving waveguide, allowing the echo light to mix with the local oscillator light. This lidar achieves optical path separation between the probe light and the echo light through the transmitting and receiving waveguides in the silicon photonics chip. However, the silicon photonics chip needs to be connected to optoelectronic devices such as lasers and optical amplifiers via optical fibers. The coupling between the silicon photonics chip and the optical fiber results in approximately 30% energy loss, leading to relatively high power consumption in the lidar. Summary of the Invention

[0003] This application provides an optical transceiver module and a lidar, which can solve the problem of high energy loss caused by the use of silicon photonics chips to separate the detection light and the echo light in related technologies.

[0004] In a first aspect, embodiments of this application provide an optical transceiver module, which includes:

[0005] The first beam splitter has a first port, a second port and a third port, for receiving a first beam through the first port and polarizing and splitting the beam so that the second port outputs a probe beam and the third port outputs a local oscillator beam, wherein the polarization direction of the probe beam is perpendicular to that of the local oscillator beam.

[0006] A polarizing beam splitter has a fourth port, a fifth port, and a sixth port. The fourth port is connected to the second port, and the sixth port is adjacent to the third port. The polarizing beam splitter is used to receive the probe light via the fourth port and output the probe light via the fifth port to detect a target object, and to receive echo light via the fifth port and output at least a portion of the echo light via the sixth port, wherein the echo light is formed by the reflection of the probe light from the target object.

[0007] A second beam splitter has a seventh port, an eighth port, a ninth port, and a tenth port. The seventh port is connected to the sixth port, and the eighth port is adjacent to the seventh port and located on the side of the seventh port closer to the first beam splitter. The second beam splitter is used to receive the echo light output from the sixth port via the seventh port and split the echo light, and to receive the local oscillator light via the eighth port and split the local oscillator light, such that a portion of the echo light and a portion of the local oscillator light are mixed to form a second beam, which is output via the ninth port. The remaining portion of the echo light and the remaining portion of the local oscillator light are mixed to form a third beam, which is output via the tenth port. The second beam and the third beam are 180 degrees out of phase.

[0008] The first reflection unit is disposed facing the third port and the eighth port, and is used to reflect the local oscillator light to the eighth port.

[0009] In some embodiments, the first reflective unit satisfies any of the following conditions:

[0010] a) The first reflecting unit is a reflecting prism, which reflects the local oscillator light by total internal reflection;

[0011] b) The first reflecting unit is a reflector, which reflects the local oscillator light in a specular reflection manner.

[0012] In some embodiments, a quarter-wave plate is also included, the quarter-wave plate being disposed at the fifth port.

[0013] In some embodiments, a second reflective unit is further included, the second reflective unit satisfying any of the following conditions:

[0014] c) The second reflecting unit is disposed at the ninth port, and the second reflecting unit is used to reflect the second beam so that the second beam and the third beam are transmitted in parallel.

[0015] d) The second reflecting unit is located at the tenth port and is used to reflect the third beam so that the third beam is transmitted parallel to the second beam.

[0016] In some embodiments, the second reflective unit satisfies any of the following conditions:

[0017] e) The second reflecting unit is a reflecting prism, which reflects the local oscillator light by total internal reflection;

[0018] f) The second reflecting unit is a reflector, which reflects the local oscillator light in a specular reflection manner.

[0019] This application embodiment also provides another optical transceiver module, which includes:

[0020] The first beam splitter has a first port, a second port and a third port, and is used to receive a first beam through the first port and split the beam proportionally, so that the second port outputs a probe beam and the third port outputs a local oscillator beam.

[0021] A polarizing beam splitter has a fourth port, a fifth port, and a sixth port. The fourth port is connected to the second port, and the sixth port is adjacent to the third port. The polarizing beam splitter is used to receive the probe light via the fourth port and output the probe light via the fifth port, and to receive the echo light via the fifth port and output at least a portion of the echo light via the sixth port. The echo light is formed by the reflection of the probe light from a target object.

[0022] The second beam splitter has a seventh port, an eighth port, a ninth port, and a tenth port. The seventh port is connected to the sixth port, and the eighth port is adjacent to the seventh port and located on the side of the seventh port closer to the first beam splitter. The second beam splitter is used to receive the echo light output from the sixth port via the seventh port and split the echo light, and to receive the local oscillator light via the eighth port and split the local oscillator light, so that a portion of the echo light and a portion of the local oscillator light are mixed to form a second beam, which is output via the ninth port. The remaining portion of the echo light and the remaining portion of the local oscillator light are mixed to form a third beam, which is output via the tenth port. The second beam and the third beam are 180 degrees out of phase.

[0023] A first reflecting unit, facing the third port and the eighth port, is used to reflect the local oscillator light to the second beam splitter; and

[0024] A half-wave plate is disposed between the first reflecting unit and the third port, or between the first reflecting unit and the eighth port.

[0025] In some embodiments, the first reflective unit satisfies any of the following conditions:

[0026] h) The first reflecting unit is a reflecting prism, which reflects the local oscillator light by total internal reflection;

[0027] i) The first reflecting unit is a reflector, and the reflector reflects the local oscillator light in a specular reflection manner.

[0028] In some embodiments, a quarter-wave plate is also included, the quarter-wave plate being disposed at the fifth port.

[0029] In some embodiments, a second reflective unit is further included, the second reflective unit satisfying any of the following conditions:

[0030] j) The second reflecting unit is disposed at the ninth port, and the second reflecting unit is used to reflect the second beam so that the second beam and the third beam are transmitted in parallel.

[0031] k) The second reflecting unit is located at the tenth port. The second reflecting unit is used to reflect the third beam so that the third beam is transmitted parallel to the second beam.

[0032] In some embodiments, the second reflective unit satisfies any of the following conditions:

[0033] l) The second reflecting unit is a reflecting prism, which reflects the local oscillator light by total internal reflection;

[0034] m) The second reflecting unit is a reflector, which reflects the local oscillator light in a specular reflection manner.

[0035] Secondly, embodiments of this application provide a lidar, including a light source module, an optical transceiver module as described in any of the above, and a photoelectric detection module;

[0036] The light source module is used to generate the first beam, which includes P-beam and S-beam;

[0037] The photoelectric detection module includes a first photoelectric detection module and a second photoelectric detection module. The first photoelectric detection module is used to receive the second light beam, and the second photoelectric detection module is used to receive the third light beam.

[0038] This application also proposes another lidar, including a light source module, an optical transceiver module as described in any of the above, and a photoelectric detection module;

[0039] The light source module is used to generate the first beam, which includes a P-beam or an S-beam.

[0040] The photoelectric detection module includes a first photoelectric detection module and a second photoelectric detection module. The first photoelectric detection module is used to receive the second light beam, and the second photoelectric detection module is used to receive the third light beam.

[0041] Based on the above embodiments, the optical transceiver module proposed in this application includes a first beam splitter, a polarization beam splitter, a first reflection unit, and a second beam splitter. The optical transceiver module first receives a first beam generated by a light source module through the first port of the first beam splitter and splits it into a probe beam and a local oscillator beam. Then, it receives the probe beam through the fourth port of the polarization beam splitter and emits an echo beam through the sixth port, thereby separating the probe beam path from the echo beam path. Afterward, the second beam splitter mixes the echo beam and the local oscillator beam to form a second beam and a third beam, which are emitted from the ninth port and the tenth port, respectively. Thus, the optical transceiver module of this application achieves beam splitting of the probe beam and the local oscillator beam through the polarization beam splitter, eliminating the need for silicon photonics chip waveguides and receiving waveguides to achieve the above functions. Therefore, the use of silicon photonics chips can be avoided, thereby reducing optical coupling losses from optical fiber or spatial light to the silicon photonics chip.

[0042] Furthermore, in this embodiment, the first beam-splitting prism, polarizing beam-splitting prism, first reflecting unit, and second beam-splitting prism are interconnected. Based on this structure, the detection light and local oscillator light are split, the detection light path and the echo light path are separated, and the local oscillator light and echo light are mixed. This results in a high degree of integration for the optical transceiver module, simplifying the structure of the lidar. Moreover, in this embodiment, the second beam and the third beam are 180 degrees out of phase. Combining the first photodetector module, the second photodetector module, and the operational amplifier to form a balanced photodetector reduces signal interference and noise, improving the signal-to-noise ratio and the lidar's anti-interference capability. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of a lidar in one embodiment of this application;

[0045] Figure 2 This is a schematic diagram of an optical transceiver module in one embodiment of this application;

[0046] Figure 3 This is a schematic diagram of an optical transceiver module in another embodiment of this application;

[0047] Figure 4 This is a schematic diagram of an optical transceiver module in another embodiment of this application;

[0048] Figure 5This is a schematic diagram of an optical transceiver module in another embodiment of this application;

[0049] Figure 6 for Figure 1 A top view of the structure of the Zhongguang transceiver module.

[0050] Explanation of icon numbers:

[0051] 100. LiDAR; 10. Light source module; 30. Optical transceiver module; 31. First beam splitter prism; 31a. First port; 31b. Second port; 31c. Third port; 33. First reflection unit; 35. Polarizing beam splitter prism; 35a. Fourth port; 35b. Fifth port; 35c. Sixth port; 351. Right-angle prism; 353. Polarizing beam splitter film; 36. Second reflection unit; 37. Second beam splitter prism; 37a. Seventh port; 37b. Eighth port; 37c. Ninth port; 37d. Tenth port; 38. Quarter-wave plate; 39. Half-wave plate; 60. Lens; 70. Scanning module; 90. Photoelectric detection module; 91. First photoelectric detection module; 93. Second photoelectric detection module; a. First beam; b. Detector beam; c. Echo beam; d. Second beam; e. Third beam; f. Local oscillator beam.

[0052] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0053] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0054] Where the following description relates to the accompanying drawings, unless otherwise indicated, the same numbers in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this application as detailed in the appended claims.

[0055] In the description of this application, it should be understood that the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances. Furthermore, in the description of this application, unless otherwise stated, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, or B existing alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship.

[0056] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0057] Please refer to Figure 1 This application provides a lidar 100, which includes a light source module 10, an optical transceiver module 30, a photoelectric detection module 90, a lens 60, and a scanning module 70.

[0058] The light source module 10 is used to generate the first beam a. Please refer to... Figure 2 The optical transceiver module 30 includes a first beam splitter 31, a polarizing beam splitter 35, a second beam splitter 37, and a first reflecting unit 33. The first beam splitter 31 has a first port 31a, a second port 31b, and a third port 31c. The first beam splitter 31 receives and splits a first beam a via the first port 31a, so that the second port 31b outputs a probe light b, and the third port 31c outputs a local oscillator light f. The polarizing beam splitter 35 has a fourth port 35a, a fifth port 35b, and a sixth port 35c. The fourth port 35a is connected to the second port 31b, and the sixth port 35c is adjacent to the third port 31c. The polarizing beam splitter 35 receives the probe light b via the fourth port 35a and outputs the probe light b via the fifth port 35b to detect a target object.

[0059] Lens 60 is positioned downstream of optical transceiver module 30 along the transmission direction of probe light b to receive and collimate the probe light b emitted from optical transceiver module 30. Scanning module 70 is located downstream of lens 60 along the optical path of probe light b. Scanning module 70 receives probe light b emitted from lens 60 and performs two-dimensional deflection to form a specific detection field of view outside lidar 100. Scanning module 70 may include galvanometers and / or rotating mirrors, etc., but is not limited in this embodiment.

[0060] The target object reflects the probe light b, forming an echo light c. The echo light c passes sequentially through the scanning module 70 and the lens 60 to reach the fifth port 35b. The polarizing beam splitter 35 also receives the echo light c via the fifth port 35b and outputs at least a portion of the echo light c via the sixth port 35c. The echo light c is formed by the reflection of the probe light b from the target object. The second beam splitter 37 has a seventh port 37a, an eighth port 37b, a ninth port 37c, and a tenth port 37d. The seventh port 37a is connected to the sixth port 35c, and the eighth port 37b is adjacent to the seventh port 37a and located on the side of the seventh port 37a closer to the first beam splitter 31. The second beam splitter 37 is used to receive the echo light c output via the sixth port 35c via the seventh port 37a and to split the echo light c.

[0061] The first reflecting unit 33 is disposed facing the third port 31c and the eighth port 37b, and is used to reflect the local oscillator light f to the eighth port 37b. The second beam splitter prism 37 is used to receive the local oscillator light f through the eighth port 37b and split the local oscillator light f so that a portion of the echo light c is mixed with a portion of the local oscillator light f to form a second beam d, which is output through the ninth port 37c. The remaining portion of the echo light c is mixed with the remaining portion of the local oscillator light f to form a third beam e, which is output through the tenth port 37d.

[0062] The photoelectric detection module 90 includes a first photoelectric detection module 91 and a second photoelectric detection module 93. The first photoelectric detection module 91 is located downstream of the ninth port 37c along the transmission direction of the second beam d, and is used to receive the second beam d. The second photoelectric detection module 93 is located downstream of the tenth port 37d along the transmission direction of the third beam e, and is used to receive the third beam e. Next, in conjunction with the attached... Figures 2 to 4 The above structure will be explained in detail.

[0063] For the light source module 10, the light source module 10 includes a laser, which can be a laser in the related art. Optionally, the laser can generate a frequency-modulated continuous wave signal according to the mechanism of FMCW radar.

[0064] Please refer to Figure 2In one embodiment, the laser generates a first beam a, which includes P-beams and S-beams. A first beam splitter 31 is capable of polarization beam splitting. The first port 31a receives the first beam a and outputs a probe beam b via the second port 31b after polarization beam splitting, and outputs the local oscillator beam f via the third port 31c. Specifically, the first beam splitter 31 can be a polarization beam splitter, which includes two right-angle prisms 351 and a polarization beam splitting film 353. The inclined surfaces of the two right-angle prisms 351 are respectively connected to two opposing surfaces of the polarization beam splitting film 353. The first port 31a is the end face of the first beam splitter 31 facing the laser, the second port 31b is the end face opposite to the first port 31a, and the third port 31c is the end face adjacent to the first port 31a and the second port 31b.

[0065] In this embodiment, the first beam a, containing both P-beams and S-beams, enters the first beam splitter 31 via the first port 31a. The polarization beam splitter 353 receives the first beam a, allowing the P-beams to pass through and be directed towards the second port 31b, while simultaneously reflecting the S-beams, directing them towards the third port 31c. This results in the detection beam b output from the second port 31b being a P-beam, and the local oscillator beam f output from the third port 31c being an S-beam. Thus, the first beam splitter 31 completes the polarization splitting of the first beam a. To ensure the detection accuracy of the lidar 100, the proportion of P-beams in the first beam a is controlled to be 95% or higher, and the proportion of S-beams to be 5% or lower. This ensures a higher energy intensity of the detection beam b, thereby increasing the energy intensity of the echo beam c formed by reflection from the target object, and also increasing the energy intensity of the second beam d and the third beam e received by the photoelectric detection module 90, thus improving the detection accuracy of the lidar 100. It should be noted that even though this embodiment uses the P-beam of beam a as the probe beam and the S-beam in beam a as the local oscillator beam for illustration, it should be understood that in other embodiments, the S-beam can also be used as the probe beam and the P-beam as the local oscillator beam, in which case the positions of the second port and the third port are interchanged.

[0066] The probe light b emitted from the second port 31b enters the polarizing beam splitter 35. In this embodiment, the polarizing beam splitter 35 can also be composed of two right-angle prisms 351 and a polarizing beam splitter 353. The inclined surfaces of the two right-angle prisms 351 are respectively connected to two opposing surfaces of the polarizing beam splitter 353. The end face of the polarizing beam splitter 35 connected to the second port 31b is the fourth port 35a, the fifth port 35b is the end face opposite to the fourth port 35a, and the sixth port 35c is the end face adjacent to the third port 31c. After the probe light b (P-ray) enters the polarizing beam splitter 35 via the fourth port 35a, the polarizing beam splitter 353 receives the probe light b and transmits it to the fifth port 35b. After being reflected by an object, the probe light b forms an echo light c. The fifth port 35b also receives the echo light c, and the polarizing beam splitter 353 reflects the S-ray in the echo light c, directing this portion of the echo light c toward the sixth port 35c. Thus, the polarizing beam splitter 35 enables the probe light b to be emitted and the echo light c to be received.

[0067] In some optional embodiments, the optical transceiver module 30 further includes a quarter-wave plate 38, which is located at the fifth port 35b. The probe light b (P-beam) emitted from the fifth port 35b can pass through the quarter-wave plate 38. The probe light b passing through the quarter-wave plate 38 is converted from P-beam to circularly polarized light. Circularly polarized light changes very little during atmospheric transmission, has high stability, and is easier to detect. After being reflected by an object, the probe light b forms an echo light c. The vast majority of the echo light c is still circularly polarized light. After this part of the echo light c passes through the quarter-wave plate 38, the circularly polarized light is converted into linearly polarized light, and the polarization direction differs from the polarization direction of the probe light b emitted from the fifth port 35b by 90 degrees, forming S-beam. After the echo light c enters the polarizing beam splitter prism 35 from the fifth port 35b, most of the echo light c (converted to S-beam) is reflected to the sixth port 35c. When polarized light strikes a target object, the polarization direction of some light signals may change, but the majority of the light signals maintain their original polarization direction. Therefore, compared to not using the quarter-wave plate 38, this embodiment can receive more echo light c signals to a certain extent, improving the reception efficiency of the echo light c signals. Furthermore, the polarizing beam splitter 35 can reflect more echo light c to the sixth port 35c, causing less echo light c to return along the original optical path or interfere with other optical paths, thus protecting the laser and improving detection accuracy. It should be noted that even though this embodiment uses the P-beam of beam a as the probe light and the S-beam in beam a as the local oscillator light, it should be understood that in other embodiments, the S-beam can also be used as the probe light and the P-beam as the local oscillator light; in this case, the positions of the fifth and sixth ports can be adjusted accordingly.

[0068] The local oscillator light f emitted from the third port 31c is directed towards the first reflecting unit 33, which reflects the local oscillator light f to the eighth port 37b. Optionally, the first reflecting unit 33 can be a reflector. In this embodiment, the orientation of the third port 31c and the orientation of the eighth port 37b are set at a 90-degree angle, and the reflector is set at a 45-degree angle to both the orientations of the third port 31c and the eighth port 37b, thereby reflecting the local oscillator light f to the eighth port 37b by specular reflection. The first reflecting unit 33 can also be a reflecting prism, which has an incident surface, a reflecting surface, and an exit surface. The incident surface is connected to the third port 31c, and the exit surface is connected to the eighth port 37b. The reflecting surface is set at an angle to both the incident and exit surfaces, thereby directing the local oscillator light f towards the eighth port 37b by total internal reflection. This improves the utilization rate of the local oscillator light f and enhances the detection accuracy to a certain extent. Furthermore, the entire optical transceiver module 30 is tightly assembled and highly reliable.

[0069] The local oscillator light f and the echo light c emitted from the sixth port 35c enter the second beam splitter 37. The second beam splitter 37 can be a proportional beam splitter 37, which does not change the polarization state of the light. The seventh port 37a is the end face of the second beam splitter 37 facing the polarization beam splitter 35, the ninth port 37c is the end face opposite to the seventh port 37a, and the eighth port 37b and the tenth port 37d are opposite each other. The second beam splitter 37 can split the echo light c entering from the seventh port 37a and the local oscillator light f entering from the eighth port 37b according to a certain ratio. In this embodiment, both the echo light c and the local oscillator light f are S-beams. A portion of the echo light c and a portion of the local oscillator light f are mixed to form a second beam d, which is directed towards the ninth port 37c. The remaining echo light c and the remaining local oscillator light f are mixed to form a third beam e, which is directed towards the tenth port 37d. In this embodiment, the orientation of the ninth port 37c and the orientation of the tenth port 37d are set at a 90-degree angle, so the transmission directions of the second beam d and the third beam e are also at a 90-degree angle. Of course, provided that the echo light c injected from the seventh port 37a and the local oscillator light f injected from the eighth port 37b are split and mixed to output the second beam d and the third beam e, the embodiments of this application do not limit the orientation of the ninth port 37c and the orientation of the tenth port 37d. They can also be set at other angles, which will not be elaborated here.

[0070] Optionally, the splitting ratio of the second beam splitter 37 is 50:50, that is, the second beam splitter 37 can split the echo light c incident from the seventh port 37a into two parts with equal optical power, and can split the local oscillator light f incident from the eighth port 37b into two parts with equal optical power, thereby forming a second beam d and a third beam e with equal optical power, which are respectively received by the first photoelectric detection module 91 and the second photoelectric detection module 93.

[0071] Both the first photodetector module 91 and the second photodetector module 93 are coherent photodetectors, which facilitates the subsequent signal processing circuitry to obtain the target object's position information and velocity information relative to the lidar 100 based on the beat frequency signals of the second beam d and / or the third beam e. The first photodetector module 91 or the second photodetector module 93 can be a Ge-Si photodetector or an InGaAs photodetector. Compared to using silicon photonics chip waveguide coupling, using photodetectors for coherent reception eliminates the need for optical fibers, making assembly easier. Furthermore, photodetectors can have a larger beam receiving surface, thus supporting a greater light walk-off effect.

[0072] Alternatively, the first photoelectric detection module 91, the second photoelectric detection module 93, and an additional operational amplifier (not shown in the figure) can be combined to form a balanced photoelectric detector. In this embodiment, the second beam d and the third beam e are 180 degrees out of phase. The first photoelectric detection module 91 and the second photoelectric detection module 93 convert the corresponding second beam d and third beam e into electrical signals, respectively. The operational amplifier differentially amplifies the electrical signals corresponding to the second beam d and the third beam e, reducing interference and noise on the signal, improving the signal-to-noise ratio and the anti-interference capability of the lidar 100.

[0073] The above describes the specific implementation when the first beam a includes both P-beams and S-beams, and correspondingly, the first beam-splitting prism 31 is a polarizing beam splitter. Please refer to the following: Figure 3 and Figure 4 This application also provides another embodiment. Unlike the previous embodiment, the first beam a generated by the light source module 10 is a single linearly polarized light, i.e., one of P-light and S-light; for example, the first beam a is S-light. In this embodiment, the first beam splitter prism 31 can also be a proportional beam splitter prism, used to proportionally split the first beam a. The proportional beam splitter prism does not change the polarization state of the optical fiber. For example, if the first beam a is S-light, after it is incident from the first port 31a onto the first beam splitter prism 31, the probe light b emitted from the second port 31b and the local oscillator light f emitted from the third port 31c are still S-light. Optionally, the splitting ratio of the first beam splitter 31 is set to 99:1, meaning the optical power of the probe light b accounts for 99% of the first beam a, and the optical power of the local oscillator light f accounts for 1% of the first beam a. This ensures a higher energy intensity of the probe light b, thereby increasing the energy intensity of the echo light c formed by reflection from the target object, and also increasing the energy intensity of the second beam d and the third beam e received by the photoelectric detection module 90, thus improving the detection accuracy of the lidar 100. Of course, the splitting ratio of the first beam splitter 31 can also be other values ​​such as 98:2, 97:3, etc., and this embodiment does not limit this.

[0074] When the probe light b is S-ray, the fifth port 35b and the sixth port 35c of the polarizing beam splitter 35 are positioned opposite each other and adjacent to the fourth port 35a, so that after the probe light b enters the polarizing beam splitter 35 from the fourth port 35a, it is reflected and exits from the fifth port 35b. After being reflected by the object, the probe light b forms an echo light c. Correspondingly, the echo light c enters the polarizing beam splitter 35 from the fifth port 35b. The polarizing beam splitter 353 is used to transmit the P-ray in the echo light c, so that this part of the echo light c is directed towards the sixth port 35c.

[0075] When the probe light b is P-ray, the fifth port 35b of the polarizing beam splitter 35 is positioned opposite the fourth port 35a and adjacent to the sixth port 35c, so that the probe light b enters the polarizing beam splitter 35 from the fourth port 35a, is transmitted to the fifth port 35b, and exits. After being reflected by the object, the probe light b forms an echo light c. Correspondingly, the echo light c enters the polarizing beam splitter 35 from the fifth port 35b. The polarizing beam splitter 353 is used to reflect the S-ray in the echo light c, so that this part of the echo light c is directed towards the sixth port 35c.

[0076] In this embodiment, the optical transceiver module 30 can also have a quarter-wave plate 38 at its fifth port 35b. The probe light b (P-beam or S-beam) is converted into circularly polarized light after passing through the quarter-wave plate 38. After reflection from an object, the probe light b forms an echo light c, the vast majority of which remains circularly polarized. This portion of the echo light c, after passing through the quarter-wave plate 38, is converted into linearly polarized light, and its polarization direction differs from that of the probe light b (P-beam or S-beam) by 90 degrees. This improves the reception efficiency of the echo light c signal, protects the laser, and enhances detection accuracy.

[0077] In this embodiment, the optical transceiver module 30 further includes a half-wave plate 39, such as Figure 3 As shown, the half-wave plate 39 is disposed between the first reflecting unit 33 and the third port 31c, or, as... Figure 4 As shown, it is positioned between the first reflecting unit 33 and the eighth port 37b. The first reflecting unit 33 is used to reflect the local oscillator light f emitted from the third port 31c to the eighth port 37b. The local oscillator light f emitted from the third port 31c passes through the half-wave plate 39 before entering the eighth port 37b. The half-wave plate 39 can change the polarization direction of the local oscillator light f. For example, the local oscillator light f emitted from the third port 31c is S-light, and after passing through the half-wave plate 39, the local oscillator light f incident on the eighth port 37b is P-light. This ensures that the polarization directions of the local oscillator light f and the echo light c are the same, and they can be mixed and beat in a photoelectric detection module to obtain the position information of the target object and the velocity information relative to the lidar 100. In addition, the half-wave plate 39, in addition to the following... Figure 3and Figure 4 The arrangement shown is on the local oscillator path, but it can also be on the echo path. For example, the half-wave plate 39 is located between the sixth port 35c and the second beam splitter 37.

[0078] In summary, the optical transceiver module 30 of this application embodiment includes a first beam splitter 31, a polarizing beam splitter 35, a first reflecting unit 33, and a second beam splitter 37. The optical transceiver module 30 first receives the first beam a generated by the light source module 10 through the first port 31a of the first beam splitter 31, and splits the beam to form a probe beam b and a local oscillator beam f. Then, it receives the probe beam b through the fourth port 35a of the polarizing beam splitter 35, and emits the echo beam c through the sixth port 35c, thereby realizing the separation of the probe light path and the echo light path. Afterwards, the second beam splitter 37 mixes the echo beam c and the local oscillator beam f to form a second beam d and a third beam e, which are emitted from the ninth port 37c and the tenth port 37d, respectively. Thus, the optical transceiver module 30 of this application embodiment realizes the splitting of the probe light b and the local oscillator light f through the polarization beam splitter 35. Therefore, it is not necessary to use the transmitting waveguide and receiving waveguide of the silicon photonic chip to achieve the above function. Therefore, the use of silicon photonic chip can be avoided, thereby reducing the optical coupling loss between the optical fiber or space light and the silicon photonic chip.

[0079] Furthermore, in this embodiment, the first beam splitter 31, the polarization beam splitter 35, the first reflection unit 33, and the second beam splitter 37 are interconnected. Based on this structure, the detection light b and the local oscillator light f are split, the detection optical path and the echo optical path are separated, and the local oscillator light f and the echo light c are mixed. This results in a high degree of integration for the optical transceiver module 30, simplifying the structure of the lidar 100. Moreover, in this embodiment, the second beam d and the third beam e are 180 degrees out of phase. Combining the first photodetector module 91, the second photodetector module 93, and the operational amplifier to form a balanced photodetector can reduce signal interference and noise, improve the signal-to-noise ratio, and enhance the anti-interference capability of the lidar 100.

[0080] Please refer to Figure 5In some embodiments, the optical transceiver module 30 further includes a second reflection unit 36. Exemplarily, the second reflection unit 36 ​​is located at the tenth port 37d and is used to reflect the third beam e emitted from the tenth port 37d. Specifically, the second beam d emitted from the ninth port 37c and the third beam e emitted from the tenth port 37d are arranged at a 90-degree angle. The second reflection unit 36 ​​can be a reflector, with its surface at a 45-degree angle to both the transmission directions of the second beam d and the third beam e, causing the third beam e to undergo specular reflection on the reflector surface, resulting in the reflected third beam e propagating parallel to the second beam d. The second reflection unit 36 ​​can also be a reflecting prism, with its incident surface connected to the tenth port 37d, its exit surface adjacent to the ninth port 37c, and its reflecting surface at an angle to the end face of the tenth port 37d, so that the third beam e undergoes total internal reflection after passing through the reflecting prism and propagates parallel to the second beam d. In this embodiment, the second reflecting unit 36 ​​is preferably a reflecting prism, so that the second reflecting unit 36 ​​can be integrated and installed on the tenth port 37d. In this embodiment, the optical transceiver module 30 transmits the second beam d and the third beam e in parallel through the second reflecting unit 36. In this way, the first photoelectric detection module 91 and the second photoelectric detection module 93 can be set on the same side of the optical transceiver module 30, which facilitates the internal structure arrangement of the lidar 100 and makes assembly easier.

[0081] Of course, in another optional structural form, the second reflecting unit 36 ​​can also be disposed at the ninth port 37c to reflect the second beam d emitted from the ninth port 37c, thereby allowing the second beam d and the third beam e to propagate in parallel. Under the premise of realizing the parallel propagation of the second beam d and the third beam e, this application does not limit the angle between the second beam d emitted from the ninth port 37c and the third beam e emitted from the tenth port 37d, nor does it limit the specific structure of the second reflecting unit 36.

[0082] Please refer to the reference. Figure 1 , Figure 5 and Figure 6It is worth mentioning that, based on any of the above embodiments, the light source module 10 is used to generate multiple first beams a, each of which is transmitted in parallel. The light source module 10 includes a light source and multiple optical amplifiers. The light source generates multiple first beams a, which are arranged in parallel. Each optical amplifier corresponds to one first beam a, and the optical amplifier amplifies the beam generated by the light source to increase the optical power of the first beam a, thereby improving the detection performance of the lidar 100. In a specific embodiment, the light source may include multiple lasers, which generate the first beams a, with each optical amplifier corresponding to one laser. Multiple lasers generate multiple first beams a, which, after passing through the optical transceiver module 30, can emit multiple parallel-transmitted detection beams b. Correspondingly, the lidar 100 includes multiple photoelectric detection modules 90, which are spaced apart to receive multiple echo beams c. The number of lasers activated can be changed according to actual needs, thereby changing the detection field of view of the lidar 100.

[0083] It is understood that in other embodiments of this application, the light source may also include a laser and a beam splitter; wherein the laser is used to generate a source light signal, and the beam splitter is used to receive the source light signal and split it into multiple first beams a. Compared to using multiple lasers, the scheme of using a single laser and a beam splitter can reduce the size of the light source module 10, and due to the reduction in the number of lasers, the cost of the light source module 10 can be reduced, thereby reducing the cost of the lidar 100. Furthermore, it can also reduce the heat generation of the light source module 10 to a certain extent, thereby reducing the number of other components used for heat dissipation of the light source, and further reducing the size and cost of the lidar 100.

[0084] Furthermore, the light source can be a single-wavelength linear frequency modulated (LFM) light source or a dual-wavelength LFM light source; that is, the first beam a can be a single-wavelength laser or a dual-wavelength laser. When the first beam a is a dual-wavelength laser, the sweep waveforms of the two wavelengths are different; correspondingly, the second beam d and the third beam e are also dual-wavelength lasers. The second beam d or the third beam e can beat on the same photodetector module, or a wave-splitting element, such as a dichroic mirror, can be set upstream of the first photodetector module 91 or the second photodetector module 93 along the transmission direction of the second beam d or the third beam e. The dichroic mirror can separate the beams according to the wavelength. Its two sides are coated with a filter film and an anti-reflection film, respectively. The dichroic mirror exhibits high transmittance or high reflectivity for beams of different wavelengths, and has advantages such as high transmittance, accurate wavelength positioning, and low light energy loss. In this way, the second beam d or the third beam e is split into two wavelength beams, and beats on two first photodetector modules 91 or two second photodetector modules 93, respectively. Single-wavelength laser detection schemes require the frequencies corresponding to two different sweep waveforms to work together to calculate the distance and velocity of the target object. For example, taking a laser as a triangular wave sweep signal, related technologies need to use the beat frequencies corresponding to the upper and lower sweep frequencies to calculate the distance beat frequency and velocity beat frequency, thereby further determining the distance and velocity of the target object. In contrast, dual-wavelength laser detection schemes use two laser wavelengths with different sweep waveforms. Therefore, the beat frequencies corresponding to the two signals at the same time can be used to calculate the distance beat frequency and velocity beat frequency, thereby further determining the distance and velocity of the target object.

[0085] In the accompanying drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components. In the description of this application, it should be understood that if terms such as "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting this application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0086] The above are merely preferred embodiments of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. An optical transceiver module, characterized in that, include: The first beam splitter has a first port, a second port and a third port, for receiving a first beam through the first port and polarizing and splitting the beam so that the second port outputs a probe beam and the third port outputs a local oscillator beam, wherein the polarization direction of the probe beam is perpendicular to that of the local oscillator beam. A polarizing beam splitter has a fourth port, a fifth port, and a sixth port. The fourth port is connected to the second port, and the sixth port is adjacent to the third port. The polarizing beam splitter is used to receive the probe light via the fourth port and output the probe light via the fifth port to detect a target object, and to receive echo light via the fifth port and output at least a portion of the echo light via the sixth port, wherein the echo light is formed by the reflection of the probe light from the target object. The second beam splitter has a seventh port, an eighth port, a ninth port, and a tenth port. The seventh port is connected to the sixth port, and the eighth port is adjacent to the seventh port and located on the side of the seventh port closer to the first beam splitter. The second beam splitter is used to receive the echo light output from the sixth port via the seventh port and split the echo light, and to receive the local oscillator light via the eighth port and split the local oscillator light, so that a portion of the echo light and a portion of the local oscillator light are mixed to form a second beam, which is output via the ninth port. The remaining portion of the echo light and the remaining portion of the local oscillator light are mixed to form a third beam, which is output via the tenth port. The second beam and the third beam are 180 degrees out of phase. as well as The first reflection unit is disposed facing the third port and the eighth port, and is used to reflect the local oscillator light to the eighth port.

2. The optical transceiver module as described in claim 1, characterized in that, The first reflective unit satisfies any of the following conditions: a) The first reflecting unit is a reflecting prism, which reflects the local oscillator light by total internal reflection; b) The first reflecting unit is a reflector, which reflects the local oscillator light in a specular reflection manner.

3. The optical transceiver module as described in claim 1, characterized in that, It also includes a quarter-wave plate, which is located at the fifth port.

4. The optical transceiver module as described in claim 1, characterized in that, It also includes a second reflective unit, which satisfies any of the following conditions: c) The second reflecting unit is disposed at the ninth port, and the second reflecting unit is used to reflect the second beam so that the second beam and the third beam are transmitted in parallel. d) The second reflecting unit is located at the tenth port and is used to reflect the third beam so that the third beam is transmitted parallel to the second beam.

5. The optical transceiver module as described in claim 4, characterized in that, The second reflective unit satisfies any of the following conditions: e) The second reflecting unit is a reflecting prism, which reflects the local oscillator light by total internal reflection; f) The second reflecting unit is a reflector, which reflects the local oscillator light in a specular reflection manner.

6. An optical transceiver module, characterized in that, include: The first beam splitter has a first port, a second port and a third port, and is used to receive a first beam through the first port and split the beam proportionally, so that the second port outputs a probe beam and the third port outputs a local oscillator beam. A polarizing beam splitter has a fourth port, a fifth port, and a sixth port. The fourth port is connected to the second port, and the sixth port is adjacent to the third port. The polarizing beam splitter is used to receive the probe light via the fourth port and output the probe light via the fifth port, and to receive the echo light via the fifth port and output at least a portion of the echo light via the sixth port. The echo light is formed by the reflection of the probe light from a target object. The second beam splitter has a seventh port, an eighth port, a ninth port, and a tenth port. The seventh port is connected to the sixth port, and the eighth port is adjacent to the seventh port and located on the side of the seventh port closer to the first beam splitter. The second beam splitter is used to receive the echo light output from the sixth port via the seventh port and split the echo light, and to receive the local oscillator light via the eighth port and split the local oscillator light, so that a portion of the echo light and a portion of the local oscillator light are mixed to form a second beam, which is output via the ninth port. The remaining portion of the echo light and the remaining portion of the local oscillator light are mixed to form a third beam, which is output via the tenth port. The second beam and the third beam are 180 degrees out of phase. The first reflection unit is disposed facing the third port and the eighth port, and is used to reflect the local oscillator light to the second beam splitter. as well as A half-wave plate is disposed between the first reflecting unit and the third port, or between the first reflecting unit and the eighth port.

7. The optical transceiver module as described in claim 6, characterized in that, The first reflective unit satisfies any of the following conditions: h) The first reflecting unit is a reflecting prism, which reflects the local oscillator light by total internal reflection; i) The first reflecting unit is a reflector, and the reflector reflects the local oscillator light in a specular reflection manner.

8. The optical transceiver module as described in claim 6, characterized in that, It also includes a quarter-wave plate, which is located at the fifth port.

9. The optical transceiver module as described in claim 6, characterized in that, It also includes a second reflective unit, which satisfies any of the following conditions: j) The second reflecting unit is disposed at the ninth port, and the second reflecting unit is used to reflect the second beam so that the second beam and the third beam are transmitted in parallel. k) The second reflecting unit is located at the tenth port. The second reflecting unit is used to reflect the third beam so that the third beam is transmitted parallel to the second beam.

10. The optical transceiver module as described in claim 9, characterized in that, The second reflective unit satisfies any of the following conditions: l) The second reflecting unit is a reflecting prism, which reflects the local oscillator light by total internal reflection; m) The second reflecting unit is a reflector, which reflects the local oscillator light in a specular reflection manner.

11. A lidar, characterized in that, Includes a light source module, an optical transceiver module as described in any one of claims 1 to 10, and a photoelectric detection module; The light source module is used to generate the first beam, which includes P-beam and S-beam; The photoelectric detection module includes a first photoelectric detection module and a second photoelectric detection module. The first photoelectric detection module is used to receive the second light beam, and the second photoelectric detection module is used to receive the third light beam.

12. A lidar, characterized in that, Includes a light source module, an optical transceiver module as described in any one of claims 1 to 10, and a photoelectric detection module; The light source module is used to generate the first beam, which includes a P-beam or an S-beam. The photoelectric detection module includes a first photoelectric detection module and a second photoelectric detection module. The first photoelectric detection module is used to receive the second light beam, and the second photoelectric detection module is used to receive the third light beam.

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