LIDAR sensor system including dual-polarized transceiver antenna

Abstract

We provide a LiDAR sensor system that includes LiDAR pixels equipped with a dual-polarization transceiver optical antenna. [Solution] The LIDAR sensor system includes a dual-polarized light antenna, a single-polarized light antenna, a first receiver, and a second receiver. The dual-polarized light antenna is configured to (i) emit a transmit beam having a first polarization direction and (ii) detect a return beam having a second polarization direction. The single-polarized light antenna is configured to detect a return beam having a second polarization direction.

Description

Technical Field

[0001] Related applications This application claims priority to U.S. Application No. 47 / 848,467, filed June 23, 2022, which is incorporated herein by reference.

Background Art

[0002] Frequency Modulated Continuous Wave (FMCW) Light Detection and Ranging (LIDAR) transmits a frequency-modulated light beam and detects the return signal to directly measure the distance and velocity of an object. Currently, the automotive industry is developing autonomous functions for controlling vehicles in certain situations. According to the SAE International Standard J3046, there is a range of six levels of autonomy, from level 0 (no autonomy) to level 5 (a vehicle that can be operated without driver input under all conditions). Vehicles with autonomous functions sense the environment in which the vehicle is traveling using sensors. Data collection and processing from the sensors enable the vehicle to drive while exploring the environment.

Summary of the Invention

[0003] Embodiments of the present disclosure include a Light Detection and Ranging (LIDAR) sensor system including one or more LIDAR pixels. At least one of the one or more LIDAR pixels can include a dual-polarization optical antenna, a first receiver, and a second receiver. The dual-polarization optical antenna can be configured to (i) emit a transmit beam having a first polarization direction and (ii) detect a return beam having a second polarization direction. The first receiver can be configured to generate a first signal in response to receiving the return beam in the second polarization direction and in response to a first local oscillator signal. The second receiver can be configured to generate a second signal in response to receiving the return beam in the second polarization direction from the dual-polarization optical antenna and in response to a second local oscillator signal.

[0004] In one embodiment, a bipolarized light antenna includes a two-dimensional (2D) polarization-dividing grating coupler having a first port and a second port. The 2D polarization-dividing grating may be configured to receive a transmitted signal at the first port and to provide a return beam having a second polarization at the second port, which is coupled to a second receiver.

[0005] In one embodiment, the LIDAR sensor system further includes a single-polarization antenna configured to detect a return beam having a second polarization direction. The single-polarization antenna may be coupled to a first receiver to provide the second polarization direction of the return beam to the first receiver.

[0006] In one embodiment, the single-polarized light antenna is a one-dimensional (1D) polarization grating coupler.

[0007] In one embodiment, a dual-polarized light antenna is offset by a specific distance from a single-polarized light antenna.

[0008] In one embodiment, the first polarization direction is perpendicular to the second polarization direction.

[0009] In one embodiment, the LIDAR sensor system further includes a single-polarization light antenna configured to detect a return beam having a second polarization direction.

[0010] In one embodiment, the first local oscillator signal is polarized in a third polarization direction, the second local oscillator signal is polarized in a third polarization direction, and the transmit signal is polarized to the third polarization before transmission. The bipolarized light antenna may be configured to couple the transmit signal into free space as a transmit beam.

[0011] In one embodiment, a bipolarized light antenna is configured to couple the return beam as a return signal to at least one of one or more LIDAR pixels. The return signal may be polarized in a third polarization direction.

[0012] In one embodiment, the third polarization direction is either the first polarization direction or the second polarization direction.

[0013] In one embodiment, the first receiver includes a first optical mixer, and the second receiver includes a second optical mixer. The first receiver may include a first diode pair coupled to the first optical mixer and be configured to provide a first electrical signal. The first electrical signal may be a first signal. The second receiver may include a second diode pair coupled to the second optical mixer and be configured to provide a second electrical signal. The second electrical signal may be a second signal.

[0014] In one embodiment, the transmit beam and the return beam are narrowband near-infrared wavelengths.

[0015] In one embodiment, the return beam is the transmitted beam reflected from the object.

[0016] Embodiments of the present disclosure include an autonomous vehicle control system for an autonomous vehicle. The autonomous vehicle control system may include a LiDAR (Light Detection and Distance Measurement) device and one or more processors. The LiDAR device may include one or more LiDAR pixels. At least one of the one or more LiDAR pixels may include a bipolarized light antenna, a first receiver and a second receiver. The bipolarized light antenna may be configured to (i) emit a transmit beam having a first polarization direction and (ii) detect a return beam having a second polarization direction. The first receiver may be configured to generate a first electrical signal in response to receiving the second polarization direction of the return beam and in response to a first local oscillator signal. The second receiver may be configured to generate a second electrical signal in response to receiving the second polarization direction of the return beam from the bipolarized light antenna and in response to a second local oscillator signal. One or more processors may be configured to control the autonomous vehicle in response to the first and second electrical signals.

[0017] In one embodiment, a bipolarized light antenna includes a two-dimensional (2D) polarization-dividing grating coupler having a first port and a second port. The 2D polarization-dividing grating may be configured to receive a transmitted signal at the first port and to provide a return beam having a second polarization at the second port, which is coupled to a second receiver.

[0018] In one embodiment, at least one of one or more LIDAR pixels further includes a single-polarization light antenna configured to detect a return beam having a second polarization direction. The single-polarization light antenna may be coupled to a first receiver to provide the second polarization direction of the return beam to the first receiver.

[0019] In one embodiment, the single-polarized light antenna is a one-dimensional (1D) polarization grating coupler.

[0020] In one embodiment, a dual-polarized light antenna is offset by a specific distance from a single-polarized light antenna.

[0021] In one embodiment, the autonomous vehicle control system further includes a rotating mirror and a birefringent slab. The rotating mirror may be configured to direct a transmit beam to a LiDAR environment and a return beam to at least one of one or more LiDAR pixels. The birefringent slab may be positioned between the rotating mirror and at least one of one or more LiDAR pixels. The birefringent slab may be configured to direct a return beam having a second polarization direction to a single-polarization antenna or a double-polarization antenna.

[0022] Embodiments of the present disclosure include an autonomous vehicle. The autonomous vehicle may include a LiDAR (Light Detection and Distance Measurement) device and one or more processors. The LiDAR device may include one or more LiDAR pixels. At least one of the one or more LiDAR pixels may include a bipolarized light antenna, a first receiver and a second receiver. The bipolarized light antenna may be configured to (i) emit a transmit beam having a first polarization direction and (ii) detect a return beam having a second polarization direction. The first receiver may be configured to generate a first electrical signal in response to receiving the second polarization direction of the return beam and in response to a first local oscillator signal. The second receiver may be configured to generate a second electrical signal in response to receiving the second polarization direction of the return beam from the bipolarized light antenna and in response to a second local oscillator signal. One or more processors may be configured to control the autonomous vehicle in response to the first and second signals.

[0023] Embodiments of the present disclosure include a light detection and distance measurement (LIDAR) sensor system comprising one or more LIDAR pixels. At least one of the one or more LIDAR pixels may include a bipolarized light antenna, a first receiver, and a second receiver. The bipolarized light antenna may be configured to (i) emit a transmit beam having a first polarization direction and (ii) detect a return beam having a second polarization direction. The first receiver may be configured to generate a first signal in response to receiving the second polarization direction of the return beam and in response to a first local oscillator signal. The second receiver may be configured to generate a second signal in response to receiving the second polarization direction of the return beam from the bipolarized light antenna and in response to a second local oscillator signal.

[0024] In one embodiment, a bipolarized light antenna includes a two-dimensional (2D) polarization-dividing grating coupler having a first port and a second port. The 2D polarization-dividing grating may be configured to receive a transmitted signal at the first port and to provide a return beam having a second polarization at the second port, which is coupled to a second receiver.

[0025] In one embodiment, the LIDAR sensor system further includes a single-polarization optical antenna configured to detect a return beam having a second polarization direction. The single-polarization optical antenna can be coupled to a first receiver to provide the second polarization direction of the return beam to the first receiver.

[0026] In one embodiment, the single-polarization optical antenna is a one-dimensional (1D) polarization grating coupler.

[0027] In one embodiment, the dual-polarization optical antenna is offset from the single-polarization optical antenna by a specific distance.

[0028] In one embodiment, the first polarization direction is orthogonal to the second polarization direction.

[0029] In one embodiment, the LIDAR sensor system further includes a single-polarization optical antenna configured to detect a return beam having a second polarization direction.

[0030] In one embodiment, the first local oscillator signal is polarized in a third polarization direction, the second local oscillator signal is polarized in the third polarization direction, and the transmission signal is polarized in the third polarization before transmission. The dual-polarization optical antenna can be configured to couple the transmission signal into free space as a transmission beam.

[0031] In one embodiment, the dual-polarization optical antenna is configured to couple the return beam as a return signal to at least one of one or more LIDAR pixels. The return signal can be polarized in the third polarization direction.

[0032] In one embodiment, the third polarization direction is the first polarization direction or the second polarization direction.

[0033] In one embodiment, the first receiver includes a first optical mixer, and the second receiver includes a second optical mixer. The first receiver may include a first diode pair coupled to the first optical mixer and be configured to provide a first electrical signal. The first electrical signal may be a first signal. The second receiver may include a second diode pair coupled to the second optical mixer and be configured to provide a second electrical signal. The second electrical signal may be a second signal.

[0034] In one embodiment, the transmit beam and the return beam are narrowband near-infrared wavelengths.

[0035] In one embodiment, the return beam is the transmitted beam reflected from the object.

[0036] Embodiments of the present disclosure include an autonomous vehicle control system for an autonomous vehicle. The autonomous vehicle control system may include a LiDAR (Light Detection and Distance Measurement) device and one or more processors. The LiDAR device may include one or more LiDAR pixels. At least one of the one or more LiDAR pixels may include a bipolarized light antenna, a first receiver and a second receiver. The bipolarized light antenna may be configured to (i) emit a transmit beam having a first polarization direction and (ii) detect a return beam having a second polarization direction. The first receiver may be configured to generate a first electrical signal in response to receiving the second polarization direction of the return beam and in response to a first local oscillator signal. The second receiver may be configured to generate a second electrical signal in response to receiving the second polarization direction of the return beam from the bipolarized light antenna and in response to a second local oscillator signal. One or more processors may be configured to control the autonomous vehicle in response to the first and second electrical signals.

[0037] In one embodiment, a bipolarized light antenna includes a two-dimensional (2D) polarization-dividing grating coupler having a first port and a second port. The 2D polarization-dividing grating may be configured to receive a transmitted signal at the first port and to provide a return beam having a second polarization at the second port, which is coupled to a second receiver.

[0038] In one embodiment, at least one of one or more LIDAR pixels further includes a single-polarization light antenna configured to detect a return beam having a second polarization direction. The single-polarization light antenna may be coupled to a first receiver to provide the second polarization direction of the return beam to the first receiver.

[0039] In one embodiment, the single-polarized light antenna is a one-dimensional (1D) polarization grating coupler.

[0040] In one embodiment, a dual-polarized light antenna is offset by a specific distance from a single-polarized light antenna.

[0041] In one embodiment, the autonomous vehicle control system further includes a rotating mirror and a birefringent slab. The rotating mirror may be configured to direct a transmit beam to a LiDAR environment and a return beam to at least one of one or more LiDAR pixels. The birefringent slab may be positioned between the rotating mirror and at least one of one or more LiDAR pixels. The birefringent slab may be configured to direct a return beam having a second polarization direction to a single-polarization antenna or a double-polarization antenna.

[0042] Embodiments of the present disclosure include an autonomous vehicle. The autonomous vehicle may include a LiDAR (Light Detection and Distance Measurement) device and one or more processors. The LiDAR device may include one or more LiDAR pixels. At least one of the one or more LiDAR pixels may include a bipolarized light antenna, a first receiver and a second receiver. The bipolarized light antenna may be configured to (i) emit a transmit beam having a first polarization direction and (ii) detect a return beam having a second polarization direction. The first receiver may be configured to generate a first electrical signal in response to receiving the second polarization direction of the return beam and in response to a first local oscillator signal. The second receiver may be configured to generate a second electrical signal in response to receiving the second polarization direction of the return beam from the bipolarized light antenna and in response to a second local oscillator signal. One or more processors may be configured to control the autonomous vehicle in response to the first and second signals. [Brief explanation of the drawing]

[0043] Non-limiting and non-exclusive embodiments of the present invention are described with reference to the following drawings, where the same reference numerals refer to the same parts in various drawings unless otherwise specified.

[0044] [Figure 1] This disclosure illustrates a LiDAR system including LiDAR pixels according to an embodiment of this disclosure.

[0045] [Figure 2a] and [Figure 2b] An example of a coherent receiver according to an embodiment of the present disclosure is shown.

[0046] [Figure 3] This disclosure illustrates a LiDAR system comprising LiDAR pixels, a birefringent slab, and a rotating mirror according to an embodiment of this disclosure.

[0047] [Figure 4a]A block diagram of an example of a system environment for an autonomous vehicle according to an embodiment of this disclosure is shown.

[0048] [Figure 4b] A block diagram of an example of a system environment for an autonomous commercial truck vehicle according to an embodiment of this disclosure is shown.

[0049] [Figure 4c] A block diagram of an example of a system environment for an autonomous commercial truck vehicle according to an embodiment of this disclosure is shown.

[0050] [Figure 4d] A block diagram of an example of a system environment for an autonomous commercial truck vehicle according to an embodiment of this disclosure is shown. [Modes for carrying out the invention]

[0051] Embodiments of a LiDAR pixel equipped with a bipolarized transceiver antenna are described below. A LiDAR pixel may comprise one or more modules, one or more integrated chips, or one or more electrical circuits. Furthermore, a LiDAR pixel may be implemented as a single package chip, or it may be implemented as a modular design comprising multiple package chips. Numerous specific details are presented in the following description to provide a complete understanding of the implementation. However, those skilled in the art will recognize that the techniques described herein can be implemented without one or more specific details, using other methods, components, materials, etc. In other cases, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects.

[0052] Throughout this specification, any reference to “one embodiment” or “embodiment” means that a particular feature, structure, or characteristic described in relation to an embodiment is included in at least one embodiment of the present invention. Therefore, not all occurrences of the phrase “in one embodiment” or “in an embodiment” in this specification necessarily refer to the same embodiment. Furthermore, a particular feature, structure, or characteristic can be combined in any suitable manner in one or more embodiments.

[0053] Throughout this specification, several technical terms are used. Unless these terms are specifically defined herein or the context of use clearly indicates otherwise, they have the ordinary meanings in the art from which they are derived. For the purposes of this disclosure, the term “Autonomous Vehicle” includes vehicles with autonomous functions having any level of autonomy as defined in SAE international standard J3046.

[0054] In some aspects of this disclosure, visible light can be defined as having a wavelength range of about 380 nm to 700 nm. Non-visible light can be defined as light having wavelengths outside the range of visible light, such as ultraviolet and infrared light. Infrared light with a wavelength range of about 700 nm to 1 mm includes near-infrared light. In some aspects of this disclosure, near-infrared light can be defined as having a wavelength range of about 700 nm to 4600 nm.

[0055] Frequency-modulated continuous wave (FMCW) LiDAR transmits a frequency-modulated light beam to an object / target to directly measure its distance and velocity. Light reflected from the object / target can be coupled with a tapped version of the light beam. The frequency of the resulting beat signal is proportional to the distance from the LiDAR system to the object, after being corrected for Doppler shift, which requires a second measurement. The two measurements, which may or may not be performed simultaneously, provide both distance and velocity information.

[0056] Embodiments of the present disclosure include a LiDAR apparatus comprising a LiDAR pixel having an optical antenna, a receiving optical antenna, a first receiver, and a second receiver. The optical antenna is a bipolarized optical antenna that emits a transmit beam in a first polarization direction and detects a return beam having a second polarization direction. The receiving optical antenna may be coupled to the first receiver to provide a return beam having a second polarization direction. The bipolarized optical antenna may be coupled to the second receiver to provide a return beam having a second polarization direction. The first receiver generates a first signal in response to receiving the second polarization direction of the return beam detected by the receiving optical antenna, and the second receiver generates a second signal in response to receiving the second polarization direction of the return beam detected by the bipolarized optical antenna. Detecting the return beam at a position offset from the transmit antenna may improve the signal-to-noise ratio (SNR) of the detected return beam, and thus improve the image quality of the LiDAR system. Also, detecting two different positions of the return beam allows the LiDAR system to detect additional information about the external environment, such as objects located in a more diverse range within the external environment of the LiDAR system. Such embodiments and other embodiments will be described in more detail with reference to Figures 1 to 4d.

[0057] Figure 1 shows a LiDAR system 100 including a LiDAR pixel 102 according to an embodiment of the present disclosure. According to one embodiment, the LiDAR pixel 102 includes an optical antenna 104, a receiving optical antenna 106, a first coherent receiver 121, and a second coherent receiver 126. However, the present invention is not limited to the specific LiDAR pixel architecture shown in Figure 1. LiDAR pixels can be implemented using any suitable chip design architecture. For example, the transmitting and receiving optical antennas may be implemented as a single module or a single integrated chip, or as separate modules or chips. Another example is that the first and second coherent receivers may be implemented as a single module or a single integrated chip, or as separate modules or chips. The optical antenna 104 may be configured to emit a transmit beam having a first polarization direction and to detect a return beam having a second polarization direction. The receiving optical antenna 106 may be located at a distance D from the optical antenna 104 to explain or compensate for beam walk-off caused by the LiDAR system rotating mirror. The transmitting beam may be an infrared transmitting beam. The transmitting beam may be a near-infrared transmitting beam. The transmitting beam may be emitted in a single defined polarization direction. In Figure 1, according to the embodiment, the optical antenna 104 is shown as a bipolarized optical coupler and can transmit a transmitting beam in response to receiving a transmitting signal 108 through the waveguide 109. The transmitting signal 108 may be generated by a laser, and the transmitting beam emitted by the optical antenna 104 may have a very narrow linewidth (e.g., less than 1 nm).

[0058] In some embodiments, the optical antenna 104 may include a bipolarized transceiver optical antenna that can be configured to emit a transmit signal having a first polarization direction and to detect a return beam having a second polarization direction (for example, simultaneously). The return beam may be a reflection of the transmit beam reflected from an object in the external environment of the LIDAR system 100. The first polarization direction may be orthogonal to the second polarization direction. In some embodiments, the orthogonality may have a margin range of 0 to 10%. For example, orthogonality can be defined as having an angle between 80 and 100 degrees with respect to the second polarization direction. The optical antenna 104 can be implemented as a two-dimensional (2D) polarization splitting grating coupler having two ports. The first port of the optical antenna 104 may be coupled to the transmit signal 108 via a waveguide 109 so that the optical antenna 104 can emit a transmit beam having a first polarization direction. The second port of the optical antenna 104 may be coupled to the second coherent receiver 126 via the waveguide 110 so that the optical antenna 104 can provide the second coherent receiver 126 with a second polarization direction for the return signal. The optical antenna 104 may be configured to couple to the waveguide 110 as a return signal that propagates the return beam from free space to the coherent receiver 126 via the waveguide 110. The return signal may have the same polarization direction as the transmit signal TX and the local oscillator signal LO2 while it is in the LIDAR pixel 102 (e.g., while it is on-chip). According to the embodiment, the polarization directions of the return signal, transmit signal TX, local oscillator signal LO1, and local oscillator signal LO2 may be the same as the first or second polarization direction, or they may be completely different polarization directions. According to the embodiment, the first polarization direction may be positive 45 degrees, and the second polarization direction may be negative 45 degrees (e.g., linear TE or TM polarization).

[0059] The receiving optical antenna 106 can be implemented as a single polarization grating coupler. The receiving optical antenna 106 can be rotated to receive and detect (e.g., couple to a waveguide) a second polarization direction of the return beam. The receiving optical antenna 106 can be rotated to negative 45-degree polarized light. The receiving optical antenna 106 can be offset by a distance D from the position of the optical antenna 104 so that the receiving optical antenna 106 can compensate for beam walk-off, for example, as shown in Figure 3. The receiving optical antenna 106 can be coupled to the first coherent receiver 121 via the first waveguide 112 to provide the first coherent receiver 121 with a second polarization direction of the return beam.

[0060] In some embodiments, the first coherent receiver 121 may be configured to generate a first signal 123 in response to a second polarization direction of the return beam and a first local oscillator signal LO 1131. The first local oscillator signal 131 may be an optical signal having a second polarization direction. In Figure 1, according to the embodiment, the second polarization direction of the return beam is received by the first coherent receiver 121 from the receiving optical antenna 106 via waveguide 112, and the first local oscillator signal 131 is received by the first coherent receiver 121 via waveguide 132. The first signal 123 may be an electrical signal provided to the processing logic 150 via communication channel 122.

[0061] In some embodiments, the second coherent receiver 126 may be configured to generate a second signal 128 in response to receiving a second polarization direction of the return beam and a second local oscillator signal LO2136. The second local oscillator signal 136 may be an optical signal having a second polarization direction. In Figure 1, according to the embodiment, the second polarization direction of the return beam is received by the second coherent receiver 126 from the optical antenna 104 via the waveguide 110, and the second local oscillator signal 136 is received by the second coherent receiver 126 via the waveguide 137. The second signal 128 may be an electrical signal provided to the processing logic 150 via the communication channel 127.

[0062] In some embodiments, the processing logic 150 may be configured to generate an image 155 in response to receiving a first signal 123 and a second signal 128 from a first coherent receiver 121 and a second coherent receiver 126, respectively. The LIDAR system 100 may include an array of LIDAR pixels 102 configured to provide the processing logic 150 with a first signal (e.g., signal 123) and a second signal (e.g., signal 128). Here, the processing logic 150 may generate an image 155 with a plurality of LIDAR pixels 102 in the LIDAR pixel array in response to the first and second signals received by the processing logic 150.

[0063] In an example of operation, the transmit signal 108 can be emitted into free space as a transmit beam by the optical antenna 104. The transmit beam propagates through one or more lenses, is reflected by a rotating mirror, and can then propagate through the external environment until it encounters an object. A portion of the transmit beam that encounters the object may be reflected again as a return beam towards the LIDAR system 100 and LIDAR pixels 102. The return beam is reflected by the rotating mirror and propagates through one or more lenses, but may be offset relative to the optical antenna 104 due to the time difference in mirror rotation. To compensate for this offset, the receiving optical antenna 106 may be offset by a distance D from the optical antenna 104.

[0064] Figures 2a and 2b illustrate examples of coherent receivers 121 and 126 (shown in Figure 1) according to embodiments of the present disclosure.

[0065] Figure 2a shows a coherent receiver 200. The coherent receiver 200 may include an optical mixer 202, a return beam port 204, a local oscillator port 208, and an output port 212. According to one embodiment, the optical mixer 202 may couple a return beam signal RB with a local oscillator signal LO to generate an output signal OUT. The optical mixer 202 may be configured to receive two or more optical signals. The optical mixer 202 may be coupled to receive a return beam signal RB from the return beam port 204 via a waveguide 206. According to one embodiment, the optical mixer 202 may be coupled to receive a local oscillator signal LO from the local oscillator port 208 via a waveguide 210. The optical mixer 202 may couple input signals to generate a plurality of coupled output signals OUT1 and OUT2. The number of output signals from the optical mixer is not limited to a specific number and may be any suitable number. According to the embodiment, output signals OUT1 and OUT2 are provided to a photodiode pair (including photodiodes PD1 and PD2) to convert the return beam signal RB and the local oscillator signal LO into output signals OUT. Output signals OUT may be electrical signals. Output signals OUT may be beat signals representing the distance and / or velocity of one or more objects in the environment of the LIDAR system. Each variation of these output signals OUT may provide object characteristics (e.g., distance, reflectivity) about objects in the environment to which the return beam is reflected. Object characteristics (e.g., distance, reflectivity) may enable, for example, an autonomous vehicle (e.g., a truck) to perform vehicle actions (e.g., stop, change direction, ignore) based on the characteristics of the object. Each output signal may be provided to a receiver among a plurality of receivers so that multiple output signals can be received and processed simultaneously.

[0066] Figure 2b shows an example of a coherent receiver 230 having an optical mixer 232 configured to provide a plurality of output signals OUT3, OUT4, OUT5, and OUT6 based on a return beam signal RB and a local oscillator signal LO, according to an embodiment. However, the number of output signals from the optical mixer is not limited to a specific number and may be any suitable number. According to an embodiment, the optical mixer 232 provides signals OUT3, OUT4, OUT5, and OUT6 to a photodiode configuration that converts the mixed signals into an in-phase output signal OUT_I and a quadrature output signal OUT_Q. The in-phase output signal OUT_I may be provided to output port 234, and the quadrature output signal OUT_Q may be provided to output port 236. The photodiode configuration may include photodiodes PD3, PD4, PD5, and PD6.

[0067] Figure 3 shows an example of a LiDAR system 300 that demonstrates how, according to embodiments of the present disclosure, LiDAR pixel 102 can be used to correct beam walk-off and support beam scanning.

[0068] In an example of operation, the optical antenna 104 may emit light as a transmit beam 302 having a first polarization direction (e.g., linearly polarized at 45 degrees). The transmit beam 302 may propagate through a birefringent slab 304 that introduces a small offset 306 to the position of the transmit beam 302 relative to the optical antenna 104. The transmit beam 302 may be collimated by a lens 308 and directed to a mirror 310. The lens 308 may be positioned between the birefringent slab 304 and the mirror 310. The mirror 310 may be selectively rotatable or configured to rotate continuously to scan the LIDAR environment. The transmit beam 302 may be reflected from the mirror 310 and directed to the LIDAR environment as a free-space light beam. The transmit beam 302 may propagate to an object 312 and be reflected again to a return beam 314. The object 312 may be a reflective surface, a diffusing surface, or a surface that is partially reflective and partially diffusing. Object 312 can change the polarization direction / characteristics of the return beam 314 to a different polarization direction from that of the transmit beam 302. For example, the polarization of the return beam 314 may be randomized. The return beam 314 may contain components with multiple polarization directions (e.g., circular, elliptical, linear). The return beam 314 may contain, for example, an optical component having a second polarization direction (e.g., linearly polarized at -45°) orthogonal to the first polarization direction of the transmit beam 302 (e.g., linearly polarized at +45°). Upon reflection, the return beam 314 propagates again to the mirror 310.

[0069] During the transmission time, when the transmit beam 302 and return beam 314 move to object 312 and then back to mirror 310, mirror 310 can rotate slightly. The amount of rotation may vary depending on the distance traveled by the transmit beam 302 and return beam 314. The rotation of mirror 310 allows the return beam 314 to be incident on lens 308 at a different angle than the transmit beam 302. A change in the position of the return beam 314 on mirror 310 could cause the return beam 314 to walk off or miss the optical antenna 104. However, since LIDAR pixel 102 includes a receiving optical antenna 106, if the return beam 314 returns to the receiving optical antenna 106 at an offset away from the optical antenna 104, LIDAR pixel 102 can receive the return beam 314 in a second polarization direction.

[0070] According to the embodiment, upon returning to the LIDAR pixel 102, the birefringent slab 304 can direct the return beam 314 to different positions on the LIDAR pixel 102 based on the polarization characteristics of the return beam 314. The return beam 314 may be directed to pass through the birefringent slab 304, which horizontally shifts the return beam 314 in space. If the polarization of the return beam 314 differs from the polarization of the transmit beam 302, the shift introduced by the birefringent material may differ. According to the embodiment, the birefringent slab 304 may be configured to direct the return beam 314 to a position on the LIDAR pixel 102 based on the polarization direction or characteristics of the return beam 314. According to the embodiment, the birefringent slab 304 may be configured to direct the return beam 314 along a different optical path than the transmit beam 302 based on the polarization of the two signals, in order to reduce signal interference.

[0071] In some embodiments, the relative shift of the transmit and return beams can be controlled by selecting a specific birefringent material and controlling the thickness 322 and angle 324 of the birefringent slab 304. As shown in Figure 3, the birefringent material is inclined with respect to the transmit beam 302 incident on the birefringent slab 304, and the birefringent slab 304 is inclined with respect to the return beam 314 incident on the birefringent material. In embodiments, the inclination angle 324 and thickness 322 of the birefringent slab 304 are configured to detect objects at detection distances of 50 meters or more.

[0072] In some embodiments, the birefringent slab 304 may contain LiNO3 (Lithium Nitrate). In some embodiments, the birefringent slab 304 may contain YVO4 (Yttrium Orthovanadate). However, the material of the birefringent slab is not limited to the materials described above. A material suitable for the birefringent slab can be used to optimally compensate for the walk-off caused by the rotating mirror over a wide range of object distances. For example, optimization for long-range targets may involve selecting a birefringent material with a larger horizontal shift due to the longer round-trip time it takes for the beam to be reflected off the target, propagate again, and received by the optical antennas 104, 106.

[0073] The inclined portion of the birefringent slab 304 may be part of a lens assembly or chip package assembly. This may be integrated into the same photonic chip as the coherent pixel array. Multiple coherent pixels and the inclined birefringent portion can be used together to achieve more complex operations of the FMCW LiDAR. In some embodiments, the birefringent portion may be motorized to change the inclination angle 324. In some embodiments, the birefringent slab 304 is omitted from the LiDAR system 300 between the LiDAR pixels 102 and the lens 308. In some embodiments, one or more optical elements are placed between the mirror 310 and the LiDAR pixels 102 to manipulate the polarization characteristics of the transmit beam 302 and the return beam 314. For example, one or more half-wave or quarter-wave plates may be included to change the polarization from linear to circular (or vice versa) and shift the direction by an orthogonal amount.

[0074] 1. System environment for autonomous vehicles Figure 4a is a block diagram showing an example of a system environment for an autonomous vehicle according to some embodiments.

[0075] Referring to Figure 4a, an exemplary autonomous vehicle 410A is shown in which various technologies disclosed herein can be implemented. For example, vehicle 410A may include a powertrain 492, which includes a prime mover 494 driven by an energy source 496 and capable of powering a drivetrain 498, and a control system 480, which includes directional control 482, powertrain control 484, and brake control 486. Vehicle 410A can be implemented as any various type of vehicle, including a vehicle capable of transporting people and / or cargo and operating in a variety of environments, and it will be understood that the aforementioned components 480-498 may vary considerably depending on the type of vehicle in which these components are used.

[0076] For simplicity, the embodiments discussed below focus on wheeled land vehicles such as automobiles, vans, trucks, and buses. In these embodiments, the prime mover 494 may include (above all) one or more electric motors and / or internal combustion engines. Energy sources may include, for example, a fuel system (providing, for example, gasoline, diesel, hydrogen, etc.), a battery system, solar panels or other renewable energy sources, and / or a fuel cell system. The drivetrain 498 may include wheels and / or tires, along with a transmission and / or any other mechanical drive components for converting the output of the prime mover 494 into vehicle motion, one or more brakes configured to controllably stop or decelerate the vehicle 410A, and directional or steering components suitable for controlling the trajectory of the vehicle 410A (for example, a rack and pinion steering linkage that generally pivots one or more wheels of the vehicle 410A about a vertical axis to change the angle of the wheel's rotation plane relative to the vehicle's longitudinal axis). In some embodiments, a combination of powertrain and energy source can be used (for example, in electric / gas hybrid vehicles), and in some examples, multiple electric motors (e.g., dedicated to individual wheels or axles) can be used as prime movers.

[0077] Direction control 482 may include one or more actuators and / or sensors for controlling and receiving feedback from direction or steering components to ensure that the vehicle 410A follows a desired trajectory. Powertrain control 484 may be configured to control the gears of the transmission in the drivetrain 498 to control the output of the powertrain 492, for example, to control the output of the prime mover 494, thereby enabling control of the speed and / or direction of the vehicle 410A. Brake control 486 may be configured to control one or more brakes, for example, disc or drum brakes coupled to the wheels of the vehicle, to slow down or stop the vehicle 410A.

[0078] Other vehicle types, including but not limited to off-road vehicles, all-terrain vehicles, or tracked vehicles, and construction equipment, can necessarily use different powertrains, drivetrains, energy sources, directional control, powertrain control, and brake control. Furthermore, in some embodiments, certain components may be combined, for example, when the vehicle's directional control is handled primarily by varying the output of one or more prime movers. Thus, the embodiments disclosed herein are not limited to specific applications of the disclosed technology in autonomous wheeled land vehicles.

[0079] Various levels of autonomous control for the vehicle 410A can be implemented in the vehicle control system 420, which may include one or more processors 422 and one or more memories 424, each processor 422 may be configured to execute program code instructions 426 stored in the memory 424. The processors may include, for example, graphics processing units (GPU(s)) and / or central processing units (CPU(s)).

[0080] Sensor 430 may include a variety of sensors suitable for collecting information from the surrounding environment of the vehicle for use in controlling the vehicle's movements. For example, sensor 430 may include a radar sensor 434, a LiDAR (light detection and distance measurement) sensor 436, a 3D positioning sensor 438, an accelerometer, gyroscope, magnetometer, or any sensor from satellite navigation systems such as GPS (Global Positioning System), GLONASS (Globalnaya Navigazionnaya Sputnikovaya Sistema, or Global Navigation Satellite System), BeiDou Navigation Satellite System (BDS), Galileo, or Compass. The 3D positioning sensor 438 can be used to determine the vehicle's position on Earth using satellite signals. Sensor 430 may include a camera 440 and / or an inertial measurement unit (IMU) 442. The camera 440 may be a monographic or stereographic camera and may record still images and / or video. The IMU442 may include multiple gyroscopes and accelerometers capable of detecting the linear and rotational motion of the vehicle in three directions. One or more encoders (not shown), such as wheel encoders, can be used to monitor the rotation of one or more wheels of the vehicle 410A. Each sensor 430 can output sensor data at a variety of data rates, which may differ from the data rates of other sensors 430.

[0081] The output of sensor 430 may be provided to a set of control subsystems 450, including a position estimation subsystem 452, a perception subsystem 454, a planning subsystem 456, and a control subsystem 458. The position estimation subsystem 452 may perform functions such as precisely determining the position and orientation (also called "attitude") of vehicle 410A within its surrounding environment and generally within a partial reference frame. The position of the autonomous vehicle can be compared to the positions of additional vehicles in the same environment as part of the generation of labeled autonomous vehicle data. The perception subsystem 454 may perform functions such as detecting, tracking, determining, and / or identifying objects in the environment surrounding vehicle 410A. Machine learning models can be used to track objects. The planning subsystem 456 may perform functions such as planning the trajectory of vehicle 410A within a given timeframe, with a desired destination as well as stationary and moving objects in the environment. Machine learning can be used for vehicle trajectory planning. The control subsystem 458 may perform functions such as generating appropriate control signals to control various control devices of the vehicle control system 420 to embody the planned trajectory of vehicle 410A. Machine learning models can be used to generate one or more signals to control autonomous vehicles in order to realize a planned trajectory.

[0082] It will be understood that the collection of components shown in Figure 4a for the vehicle control system 420 is merely illustrative. In some embodiments, individual sensors can be omitted. Additionally or alternatively, in some embodiments, multiple sensors of the type shown in Figure 4a can be used for redundancy and / or to cover various areas around the vehicle, and other types of sensors can be used. Similarly, various types and / or combinations of control subsystems can be used in other embodiments. Also, although subsystems 452-458 are shown to be separate from the processor 422 and memory 424, it will be understood that in some embodiments, some or all of subsystems 452-458 can reside in one or more memories 424 and be embodied by program code instructions 426 performed by one or more processors 422, and these subsystems 452-458 can, in some cases, be implemented using the same processor and / or memory. The subsystems can be implemented, at least partially, using various dedicated circuit logics, various processors, various field-programmable gate arrays (FPGAs), various application-specific integrated circuits (ASICs), various real-time controllers, and, as mentioned above, many subsystems can use circuits, processors, sensors, and / or other components. Furthermore, the various components of the vehicle control system 420 can be networked in various ways.

[0083] In some embodiments, the vehicle 410A may include an auxiliary vehicle control system (not shown) that can be used as a redundant or backup control system for the vehicle 410A. The auxiliary vehicle control system can ensure that the autonomous vehicle 410A is fully operational in the event of an adverse event occurring in the vehicle control system 420, but in other embodiments, the auxiliary vehicle control system may have only limited functions, such as performing a controlled stop of the vehicle 410A in response to an adverse event detected by the vehicle control system 420. In other embodiments, the auxiliary vehicle control system may be omitted.

[0084] In general, a variety of architectures, including various combinations of software, hardware, circuit logic, sensors, and networks, can be used to embody the various components shown in Figure 4a. For example, each processor can be embodied as a microprocessor, and each memory can include not only random access memory (RAM) devices that constitute the main memory, but also any auxiliary level of memory, such as cache memory, non-volatile or backup memory (e.g., programmable or flash memory), read-only memory, etc. Also, each memory can be considered to include memory storage devices physically located elsewhere in the vehicle 410A, such as any cache memory within the processor, as well as any storage capacity used as virtual memory (e.g., stored in mass storage or other computer controllers). One or more processors shown in Figure 4a, or completely isolated processors, can be used to embody additional functions in the vehicle 410A other than for the purpose of autonomous control, such as the operation of entertainment systems, doors, lighting, convenience functions, etc.

[0085] Furthermore, for additional storage, vehicle 410A may include one or more mass storage devices, such as removable disk drives, hard disk drives, direct access storage devices (DASDs), optical drives (e.g., CD drives, DVD drives, etc.), solid-state storage drives (SSDs), network-attached storage, storage area networks, and / or tape drives.

[0086] Furthermore, the vehicle 410A includes a user interface 464 that allows the vehicle 410A to receive a number of inputs from a user or operator and generate outputs such as one or more displays, touchscreens, voice and / or gesture interfaces, buttons and other haptic controls. Otherwise, user input may be received via other computer or electronic devices, such as an app or web interface on a mobile device.

[0087] Furthermore, the vehicle 410A may include one or more network interfaces, for example, network interface 462, which can enable the vehicle 410A to communicate with one or more networks (e.g., a short-range network (LAN), a wide-area network (WAN), a wireless network, and / or the Internet) to allow communication of information with other computers and electronic devices, including central services such as cloud services, to receive environmental and other data for use in autonomous control. Data collected by one or more sensors 430 may be uploaded to the computing system 472 via network 470 for further processing. A timestamp may be added to each instance of the vehicle data before uploading.

[0088] Each processor shown in Figure 4a, and the various additional controllers and subsystems disclosed herein, generally operate under the control of an operating system and perform, or depend upon, various computer software applications, components, programs, objects, modules, data structures, etc., as described in detail below. Furthermore, various applications, components, programs, objects, modules, etc., may be performed on one or more processors of other computers connected to the vehicle 410A via network 470, for example, processing required to embody the functionality of a computer program in a distributed, cloud-based, or client-server computing environment can be allocated to numerous computers and / or services via the network.

[0089] Generally, routines performed to embody the various embodiments described herein are referred to herein as “program code,” whether they are embodied as part of an operating system or as a specific application, component, program, object, module, or instruction sequence, or as a subset thereof. Program code may reside in various memories and storage devices for various periods of time and, when read and executed by one or more processors, may include one or more instructions that perform the steps necessary to perform steps or elements that embody various aspects of the disclosure. Furthermore, embodiments are described in the context of fully functional computers and systems, and the various embodiments described herein can be distributed as various forms of program products, and it should be understood that such embodiments can be implemented independently of the specific type of computer-readable medium used to actually distribute them.

[0090] Examples of computer-readable media include tangible, non-temporary media such as volatile and non-volatile memory devices, floppy disks and other removable disks, solid-state drives, hard disk drives, magnetic tapes, and optical disks (e.g., CD-ROMs, DVDs, etc.).

[0091] Furthermore, the various program codes described below can be identified based on the application embodied in a particular embodiment. However, it should be understood that any particular program naming convention described below is used merely for convenience, and therefore the disclosure should not be limited to use only in any particular application identified and / or implied by such naming convention. Also, considering the countless ways in which a computer program can consist of routines, procedures, methods, modules, objects, etc., and the various ways in which program functions are assigned between various software layers residing in a typical computer (e.g., operating systems, libraries, APIs, applications, applets, etc.), it should be understood that the disclosure is not limited to the specific structure and assignment of program functions described herein.

[0092] The environment shown in Figure 4a is not intended to limit the embodiments disclosed herein. In fact, other alternative hardware and / or software environments can be used without departing from the scope of the embodiments disclosed herein.

[0093] 2. FM LiDAR for Automotive Applications The truck may include a LiDAR system (e.g., vehicle control system 420 and / or LiDAR system 100 and / or 300). In some embodiments, the LiDAR system may encode an optical signal using frequency modulation and scatter the encoded optical signal into free space using optics. By detecting the frequency difference between the encoded optical signal and the return signal reflected from an object, a frequency-modulated (FM) LiDAR system can use the Doppler effect to determine the position of an object and / or accurately measure the velocity of an object. FM LiDAR systems may use continuous waves (referred to as “FMCW LiDAR” or “coherent FMCW LiDAR”) or quasi-continuous waves (referred to as “FMQW LiDAR”). The LiDAR system may encode an optical signal using phase modulation (PM) and scatter the encoded optical signal into free space using optics.

[0094] FM or phase-modulated (PM) LiDAR systems can offer significant advantages over conventional LiDAR systems for automotive and / or commercial truck transportation applications. Firstly, in some cases, objects (e.g., pedestrians wearing dark clothing) may have low reflectivity because only a small amount of light (e.g., less than 10%) that reaches the object is reflected back to the sensor of the FM or PM LiDAR system (e.g., sensor 430 in Figure 4a). In other cases, objects (e.g., shiny road signs) may have high reflectivity (e.g., more than 10%) because a large amount of light that reaches the object is reflected back to the sensor of the FM LiDAR system.

[0095] Regardless of the object's reflectivity, FM LiDAR systems can detect objects (e.g., classify, recognize, and discover) at greater distances (e.g., twice as far) than conventional LiDAR systems. For example, FM LiDAR systems can detect low-reflectivity objects at distances of 300 meters or more and high-reflectivity objects at distances of 400 meters or more.

[0096] To achieve such improvements in detection capabilities, FM LIDAR systems can utilize sensors (e.g., sensor 430 in Figure 4a). In some embodiments, these sensors may be sensitive to single photons, meaning they can detect the smallest possible amount of light. In some applications, FM LIDAR systems can utilize infrared wavelengths (e.g., 950 nm, 1550 nm, etc.), but are not limited to the infrared wavelength range (e.g., near-infrared: 800 nm to 1500 nm, mid-infrared: 1500 nm to 5600 nm, and far-infrared: 5600 nm to 1,000,000 nm). By operating FM or PM LIDAR systems at infrared wavelengths, they can broadcast stronger light pulses or beams while still meeting eye safety standards. Conventional LIDAR systems are often not sensitive to single photons and / or operate only at near-infrared wavelengths, requiring limitations on light output (and distance detection capabilities) for eye safety.

[0097] Therefore, by detecting objects at greater distances, FM LiDAR systems can gain more time to react to unexpected obstacles. In fact, for large vehicles traveling at high speeds (e.g., commercial trucks), even a few milliseconds of extra time can improve safety and convenience.

[0098] Another advantage of FM LIDAR systems is their ability to provide accurate velocity instantaneously for each data point. In some embodiments, velocity measurement is achieved using the Doppler effect, which shifts the frequency of light received from an object based on at least one of either radial velocity (e.g., the direction vector between the detected object and the sensor) or the frequency of the laser signal. For example, for velocities occurring in road conditions with speeds less than 100 meters per second (m / s), this shift at a wavelength of 1550 nanometers (nm) corresponds to a frequency shift of less than 130 megahertz (MHz). This frequency shift is too small to be directly detected in the optical domain. However, when using coherent detection in FMCW, PMCW, or FMQW LIDAR systems, the signal can be converted to the RF domain so that the frequency shift can be calculated using various signal processing techniques. This allows autonomous vehicle control systems to process the received data more quickly.

[0099] Furthermore, instantaneous velocity calculation makes it easier for FM LiDAR systems to identify distant or sparse data points as objects and / or track how these objects are moving over time. For example, an FM LiDAR sensor (e.g., sensor 430 in Figure 4a) may receive only a few returns (e.g., hits) for an object 300m away, but if these returns provide velocity values ​​of interest (e.g., moving towards the vehicle at a speed of 70mph or more), the FM LiDAR system and / or the autonomous vehicle control system can determine individual weights for the probability associated with the object.

[0100] Faster identification and / or tracking of FM LiDAR systems provides autonomous vehicle control systems with more time to steer the vehicle. It also allows autonomous vehicle control systems to plan more appropriate responses by more accurately determining the speed of moving objects.

[0101] Another advantage of FM LiDAR systems is that they are less static than conventional LiDAR systems. That is, conventional LiDAR systems, designed to be more sensitive to light, generally perform poorly in bright sunlight. Furthermore, these systems tend to suffer from crosstalk (e.g., when sensors interfere with each other's light pulses or beams) and self-interference (e.g., when sensors interfere with their own previous light pulses or beams). To overcome these drawbacks, vehicles using conventional LiDAR systems often require additional hardware, complex software, and / or more computing power to manage this "noise."

[0102] On the other hand, FM LiDAR systems do not encounter such problems because each sensor is specifically designed to respond only to its own optical characteristics (e.g., light beam, light wave, light pulse). If the returned light does not match the timing, frequency, and / or wavelength of the initially transmitted light, the FM sensor can filter (e.g., remove, ignore, etc.) that data point. Thus, FM LiDAR systems enable safer and smoother operation by producing (e.g., generating, deriving, etc.) more accurate data with fewer hardware or software requirements.

[0103] Finally, FM LiDAR systems are easier to scale than conventional LiDAR systems. As more autonomous vehicles (e.g., cars, commercial trucks, etc.) appear on the roads, vehicles powered by FM LiDAR systems are likely to avoid interference problems caused by sensor crosstalk. Also, FM LiDAR systems use less optical peak power than conventional LiDAR sensors. This allows some or all of the optical components of FM LiDAR to be manufactured on a single chip, which offers unique advantages such as those described herein.

[0104] 3. Commercial truck transport Figure 4b is a block diagram showing an example of a system environment for an autonomous commercial truck vehicle according to some embodiments. Environment 400B includes a commercial truck 402B for carrying cargo 406B. In some embodiments, the commercial truck 402B may include a vehicle configured for long-distance freight transport, regional freight transport, intermodal freight transport (i.e., a road-based vehicle is used as one of several modes of transport for transporting cargo) and / or any other road-based freight transport applications. The commercial truck 402B may be a flatbed truck, a refrigerated truck (e.g., a reefer truck), a vented van (e.g., a dry van), a moving truck, etc. The cargo 406B may be goods and / or agricultural products. The commercial truck 402B may include a trailer for carrying cargo 406B, such as a flatbed trailer, a lowboy trailer, a step-deck trailer, an expandable flatbed trailer, a side-kit trailer, etc.

[0105] Environment 400B includes object 410B (shown as another vehicle in Figure 4b) located within a distance of 30 meters or less from the truck.

[0106] The commercial truck 402B may include a LiDAR system 404B (e.g., the FM LiDAR system in Figure 4a, the vehicle control system 420, the LiDAR system 100 in Figure 1, the LiDAR system 300 in Figure 3, etc.) for determining the distance to an object 410B or measuring the speed of an object 410B. Figure 4b shows one LiDAR system 404B mounted on the front of the commercial truck 402B, but the number of LiDAR systems and the mounting area of ​​LiDAR systems in the commercial truck are not limited to a specific number and specific area. The commercial truck 402B may include any number of LiDAR systems 404B (or their components such as sensors, modulators, coherent signal generators, etc.) mounted on any area of ​​the commercial truck 402B (e.g., front, rear, sides, top, bottom, underside, and / or bottom) to facilitate object detection in any free space of the commercial truck 402B.

[0107] As shown in the diagram, the LIDAR system 404B in environment 400B may be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) that are within short distance (e.g., 30 meters or less) from the commercial truck 402B.

[0108] Figure 4c is a block diagram showing an example of a system environment for an autonomous commercial truck vehicle according to some embodiments. Environment 400C includes the same components as those included in Environment 400B (e.g., commercial truck 402B, cargo 406B, LIDAR system 404B, etc.).

[0109] Environment 400C includes objects 410C (shown as other vehicles in Figure 4c) located within a distance range of (i) 30 meters or more and (ii) 150 meters or less from the commercial truck 402B. As shown in the illustration, the LIDAR system 404B of environment 400C may be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) located at a certain distance (e.g., 100 meters) from the commercial truck 402B.

[0110] Figure 4d is a block diagram showing an example of a system environment for an autonomous commercial truck vehicle according to some embodiments. Environment 400D includes the same components as those included in Environment 400B (e.g., commercial truck 402B, cargo 406B, LIDAR system 404B, etc.).

[0111] Environment 400D includes objects 410D (shown as other vehicles in Figure 4d) that are within a distance of 150 meters or more from the commercial truck 402B. As shown in the illustration, the LIDAR system 404B of environment 400D may be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) at a distance (e.g., 300 meters) from the commercial truck 402B.

[0112] In commercial trucking applications, the increasing weight of vehicles and the correspondingly longer stopping distances necessitate the effective detection of objects at all ranges. FM LiDAR systems (e.g., FMCW and / or FMQW systems) or PM LiDAR systems are ideally suited for commercial trucking applications due to the aforementioned advantages. Ultimately, commercial trucks equipped with these systems can improve the safety of not only the commercial trucks themselves but also surrounding vehicles, as they enhance the ability to safely transport people and goods over short or long distances. In various embodiments, these FM or PM LiDAR systems can be used in semi-autonomous application areas where a driver is on board the commercial truck and some functions of the commercial truck operate autonomously using the FM or PM LiDAR system, or in fully autonomous application areas where the commercial truck operates entirely by the FM or PM LiDAR system, either alone or in combination with other vehicle systems.

[0113] 4. Continuous wave modulation and quasi-continuous wave modulation In a LiDAR system using CW modulation, the modulator continuously modulates the laser beam. For example, if the modulation period is 10 seconds, the input signal is modulated for the entire 10 seconds. Alternatively, in a LiDAR system using quasi-CW modulation, the modulator modulates the laser beam so that it has both an active and an inactive portion. For example, with a 10-second period, the modulator modulates the laser beam for only 8 seconds (also called the "active portion") and does not modulate the laser beam for 2 seconds (also called the "inactive portion"). This allows the LiDAR system to reduce power consumption by 2 seconds because the modulator does not need to provide a continuous signal.

[0114] For frequency-modulated continuous-wave (FMCW) LiDAR for automotive applications, FMCW measurement and signal processing methodologies are used, but it may be advantageous to operate the LiDAR system using quasi-CW modulation, rather than having the optical signal constantly on (e.g., activation, power supply, transmission, etc.). In some embodiments, quasi-CW modulation may have a duty cycle of 1% or more and up to 50%. If energy is consumed during the off state (e.g., deactivation, power cut-off, etc.) during the actual measurement time, the signal-to-noise ratio (SNR) can be improved and less signal processing is required, allowing all energy to be consistently integrated over a longer period of time.

[0115] In this disclosure, the term “processing logic” may include one or more processors, microprocessors, multicore processors, application-specific integrated circuits (ASICs), and / or field-programmable gate arrays (FPGAs) for performing the operations disclosed herein. In some embodiments, memory (not shown) is integrated into the processing logic to store instructions for performing operations and / or storing data. The processing logic may also include analog or digital circuits for performing operations according to embodiments of this disclosure.

[0116] The “memory” or “multiple memories” described herein may include one or more volatile or non-volatile memory architectures. “Memory” or “multiple memories” may be removable and non-removable media embodied in any way or technique for storing information such as computer-readable instructions, data structures, program modules, or other data. Examples of memory technologies may include RAM, ROM, EEPROM, flash memory, CD-ROM, DVD, high-definition multimedia / data storage disk or other optical storage, magnetic cassette, magnetic tape, magnetic disk storage, or other magnetic storage devices or other non-transmitting media that can be used to store information for access by computing equipment.

[0117] A network may include, but is not limited to, all networks or network systems, such as peer-to-peer networks, LANs (short-range networks), WANs (wide-area networks), public networks like the Internet, private networks, cellular networks, wireless networks, wired networks, combined wired and wireless networks, and satellite networks.

[0118] Communication channels include, or may be routed by, one or more wired or wireless communication using the IEEE 802.11 protocol, Bluetooth, SPI (Serial Peripheral Interface), I2C (Inter-Integrated Circuit), USB (General Purpose Serial Port), CAN (Controller Area Network), Cellular Data Protocol (e.g., 3G, 4G, LTE, 5G, etc.), Optical Communication Networks, Internet Service Providers (ISPs), Peer-to-Peer Networks, LANs, WANs, Public Networks (e.g., the "Internet"), Private Networks, Satellite Networks, or others.

[0119] Computing devices may include desktop computers, laptop computers, tablets, phablets, smartphones, feature phones, and server computers. Server computers can be located remotely in a data center or stored locally.

[0120] The processes described above are explained in terms of computer software and hardware. The described techniques may consist of machine-executable instructions embodied in tangible or non-temporary machine (e.g., computer)-readable storage media, which, when executed by a machine, cause the machine to perform the described operation. Furthermore, the processes may be implemented in hardware such as application-specific integrated circuits ("ASICs").

[0121] Tangible, non-transient, machine-readable storage media include all mechanisms that provide (i.e., store) information in a format accessible to machines (e.g., computers, network devices, personal digital assistants, manufacturing tools, and any device with one or more processor sets). For example, machine-readable storage media include recordable / non-recordable media (e.g., read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.).

[0122] The foregoing description of the exemplary embodiments of the Invention, including those described in the abstract, is not intended to limit the Invention to the complete or the exact form disclosed. Specific embodiments and examples of the Invention are described herein for illustrative purposes, but various modifications are possible within the scope of the Invention, as will be apparent to those skilled in the relevant art.

[0123] Such modifications to the present invention may be made in light of the detailed description above. The terms used in the following claims should not be construed as limiting the invention to the specific embodiments disclosed in the specification. Rather, the scope of the invention should be entirely determined by the following claims, which should be interpreted in accordance with established principles of claim interpretation.

Claims

1. A LIDAR sensor system, Equipped with one or more LiDAR pixels, At least one of the one or more LIDAR pixels is A bipolarized light antenna configured to (i) emit a transmit beam having a first polarization direction and (ii) detect a return beam having a second polarization direction, A first receiver is configured to generate a first signal in response to receiving the second polarization direction of the return beam and in response to a first local oscillator signal, A LiDAR sensor system comprising: a second receiver configured to generate a second signal in response to receiving the second polarization direction of the return beam from the bipolarized light antenna and in response to a second local oscillator signal.

2. The dual-polarized light antenna includes a two-dimensional (2D) polarization-dividing grating coupler having a first port and a second port. The LIDAR sensor system according to claim 1, wherein the 2D polarization-dividing grating is configured to receive a transmission signal at the first port and to provide the return beam having the second polarization to the second port coupled to the second receiver.

3. The system further includes a single-polarized light antenna configured to detect the return beam having the second polarization direction, The LIDAR sensor system according to claim 1, wherein the single-polarized light antenna is coupled to the first receiver to provide the first receiver with the second polarization direction of the return beam.

4. The LIDAR sensor system according to claim 3, wherein the single polarized light antenna is a one-dimensional (1D) polarized grating coupler.

5. The LIDAR sensor system according to claim 3, wherein the dual-polarized light antenna is offset by a specific distance from the single-polarized light antenna.

6. The LIDAR sensor system according to claim 1, wherein the first polarization direction is orthogonal to the second polarization direction.

7. The LIDAR sensor system according to claim 6, further comprising a single-polarized light antenna configured to detect the return beam having the second polarization direction.

8. The first local oscillator signal is polarized in the third polarization direction, the second local oscillator signal is polarized in the third polarization direction, and the transmitted signal is polarized in the third polarization direction before transmission. The LIDAR sensor system according to claim 1, wherein the dual-polarized light antenna is configured to couple the transmission signal to free space as the transmission beam.

9. The bipolarized light antenna is configured to couple the return beam as a return signal to at least one of the one or more LiDAR pixels. The LIDAR sensor system according to claim 8, wherein the return signal is polarized in the third polarization direction.

10. The LIDAR sensor system according to claim 9, wherein the third polarization direction is the first polarization direction or the second polarization direction.

11. The first receiver includes a first optical mixer, and the second receiver includes a second optical mixer. The first receiver includes a first diode pair coupled to the first optical mixer and is configured to provide a first electrical signal. The second receiver includes a second diode pair coupled to the second optical mixer and is configured to provide a second electrical signal. The LIDAR sensor system according to claim 1, wherein the second electrical signal is the second signal.

12. The LIDAR sensor system according to claim 1, wherein the transmitting beam and the return beam are narrowband near-infrared wavelengths.

13. The LIDAR sensor system according to claim 1, wherein the return beam is the transmit beam reflected from the object.

14. An autonomous vehicle control system including a LIDAR sensor system according to any one of claims 1 to 13.

15. An autonomous vehicle comprising the LIDAR sensor system according to any one of claims 1 to 13.

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