LIDAR Pixel With Dual Polarization Receiving Optical Antenna

Abstract

A light detection and ranging (LIDAR) system includes one or more LIDAR pixels including a transmit optical antenna, a receive optical antenna, a first receiver, and a second receiver. The transmit optical antenna is configured to emit a transmit beam. The receiving optical antenna is configured to detect (i) a first polarization orientation of the return beam and (ii) a second polarization orientation of the return beam.

Description

[0001] Related applications

[0002] This application is based upon and claims the benefit of U.S. non-provisional patent application No. 18 / 187,827, filed on March 22, 2023, which is a continuation-in-part of U.S. non-provisional patent application No. 17 / 836,280, filed on June 9, 2022, which issued as U.S. Patent No. 11,619,739 on April 4, 2023. All of these applications and patents are incorporated herein by reference in their entirety. Background Art

[0003] Frequency-modulated continuous wave (FMCW) light detection and ranging (LIDAR) directly measures the range and velocity of objects by emitting a frequency-modulated light beam and detecting the return signal. The automotive industry is currently developing autonomous features to control vehicles in specific situations. According to SAE International Standard J3016, there are six levels of autonomy, ranging from Level 0 (no autonomy) to Level 5 (the vehicle is capable of operating without operator input under all conditions). Vehicles with autonomous features utilize sensors to perceive the environment through which the vehicle navigates. Acquiring and processing data from the sensors allows the vehicle to navigate its environment. Summary of the Invention

[0004] Embodiments of the present disclosure include a light detection and ranging (LIDAR) system comprising one or more LIDAR pixels, wherein at least one of the one or more LIDAR pixels comprises a transmitting optical antenna, a receiving optical antenna, a first receiver, and a second receiver. The transmitting optical antenna is configured to emit a transmitting beam. The receiving optical antenna is configured to detect (i) a first polarization orientation of a returning beam and (ii) a second polarization orientation of the returning beam. The first receiver is configured to generate a first signal in response to receiving the first polarization orientation of the returning beam from the receiving optical antenna and a first local oscillator signal having the first polarization orientation. The second receiver is configured to generate a second signal in response to receiving the second polarization orientation of the returning beam from the receiving optical antenna and a second local oscillator signal having the second polarization orientation.

[0005] In one embodiment, the receiving optical antenna includes a two-dimensional (2D) polarization beam splitting grating coupler configured to couple a first polarization orientation of the return beam to the first receiver and configured to couple a second polarization orientation of the return beam to the second receiver.

[0006] In one embodiment, the receiving optical antenna includes a first single polarization grating coupler and a second single polarization grating coupler. The first single polarization grating coupler is configured to couple a first polarization orientation of the return beam to the first receiver. The second single polarization grating coupler is configured to couple a second polarization orientation of the return beam to the second receiver.

[0007] In one embodiment, the first single polarization grating coupler is offset from the second single polarization grating coupler.

[0008] In one embodiment, the first single polarization grating coupler is rotated relative to the second single polarization grating coupler.

[0009] In one embodiment, the first single polarization grating coupler is rotated approximately 90 degrees relative to the second single polarization grating coupler.

[0010] In one embodiment, the single polarization output coupler of the transmitting optical antenna is rotated relative to the first single polarization grating coupler and the second single polarization grating coupler.

[0011] In one embodiment, the transmit optical antenna includes a two-dimensional (2D) polarization grating coupler, and the transmit beam includes a first polarization orientation and a second polarization orientation.

[0012] In one embodiment, the first local oscillator signal and the second local oscillator signal have the same wavelength as the return beam.

[0013] In one embodiment, the transmit beam has a first polarization orientation.

[0014] In one embodiment, the transmit beam is infrared and the return beam is infrared.

[0015] In one embodiment, the transmit beam and the return beam are narrow-band near infrared wavelengths.

[0016] In one embodiment, the first polarization orientation is orthogonal to the second polarization orientation.

[0017] In one embodiment, the return beam is a transmit beam reflected from a target.

[0018] Embodiments of the present disclosure include an autonomous vehicle control system for an autonomous vehicle, the autonomous vehicle control system comprising a LIDAR device and one or more processors, the LIDAR device comprising one or more LIDAR pixels. At least one of the one or more LIDAR pixels comprises a transmitting optical antenna, a receiving optical antenna, a first receiver, and a second receiver. The transmitting optical antenna is configured to emit a transmitting beam. The receiving optical antenna is configured to detect (i) a first polarization orientation of a returning beam and (ii) a second polarization orientation of the returning beam. The first receiver is configured to generate a first electrical signal in response to receiving the first polarization orientation of the returning beam and a first local oscillator signal from the receiving optical antenna. The second receiver is configured to generate a second electrical signal in response to receiving the second polarization orientation of the returning beam and a second local oscillator signal from the receiving optical antenna. The one or more processors are configured to control the autonomous vehicle in response to the first electrical signal and the second electrical signal.

[0019] In one embodiment, the receiving optical antenna includes a two-dimensional (2D) polarization beam splitting grating coupler configured to couple a first polarization orientation of the return beam to the first receiver and configured to couple a second polarization orientation of the return beam to the second receiver.

[0020] In one embodiment, the receiving optical antenna includes a first single polarization grating coupler and a second single polarization grating coupler. The first single polarization grating coupler is configured to couple a first polarization orientation of the return beam to the first receiver. The second single polarization grating coupler is configured to couple a second polarization orientation of the return beam to the second receiver.

[0021] In one embodiment, the first single polarization grating coupler is rotated relative to the second single polarization grating coupler.

[0022] In one embodiment, the transmit optical antenna includes a two-dimensional (2D) polarization grating coupler, and the transmit beam includes a first polarization orientation and a second polarization orientation.

[0023] Embodiments of the present disclosure include an autonomous vehicle comprising a LiDAR sensor and one or more processors. The LiDAR sensor comprises a transmitting optical antenna, a receiving optical antenna, a first receiver, and a second receiver. The transmitting optical antenna is configured to emit a transmitting beam. The receiving optical antenna is configured to detect (i) a first polarization orientation of a returning beam and (ii) a second polarization orientation of the returning beam. The first receiver is configured to generate a first signal in response to receiving the first polarization orientation of the returning beam and a first local oscillator signal from the receiving optical antenna. The second receiver is configured to generate a second signal in response to receiving the second polarization orientation of the returning beam and a second local oscillator signal from the receiving optical antenna. The one or more processors are configured to control the autonomous vehicle in response to the first signal and the second signal.

[0024] Embodiments of the present disclosure include a light detection and ranging (LIDAR) system. The LIDAR system includes one or more LIDAR pixels. At least one LIDAR pixel in the one or more LIDAR pixels includes a transmitting optical antenna and a receiving optical antenna. The transmitting optical antenna is configured to emit a transmit beam. The receiving optical antenna includes a first single polarization grating coupler rotated +45 degrees relative to the transmitting optical antenna, wherein the first single polarization grating coupler is configured to detect a first polarization orientation of a return beam. The receiving optical antenna includes a second single polarization grating coupler rotated -45 degrees relative to the transmitting optical antenna, wherein the second single polarization grating coupler is configured to detect a second polarization orientation of the return beam. The LIDAR system includes a first receiver configured to generate a first signal in response to receiving a first polarization orientation of the return beam from the receiving optical antenna and a first local oscillator signal having the first polarization orientation. The LIDAR system also includes a second receiver configured to generate a second signal in response to receiving a second polarization orientation of the return beam from the receiving optical antenna and a second local oscillator signal having the second polarization orientation.

[0025] In one embodiment, the first single polarization grating coupler is offset from the second single polarization grating coupler.

[0026] In one embodiment, the first single polarization grating coupler is rotated relative to the second single polarization grating coupler.

[0027] In one embodiment, the first single polarization grating coupler is rotated approximately 90 degrees relative to the second single polarization grating coupler.

[0028] In one embodiment, the single polarization output coupler of the transmitting optical antenna is rotated relative to the first single polarization grating coupler and the second single polarization grating coupler.

[0029] In one embodiment, the transmit optical antenna includes a two-dimensional (2D) polarization grating coupler.The transmit beam includes a first polarization orientation and a second polarization orientation.

[0030] In one embodiment, the first local oscillator signal and the second local oscillator signal have the same wavelength as the return beam.

[0031] In one embodiment, the transmit beam has a first polarization orientation.

[0032] In one embodiment, the transmit beam is infrared and the return beam is infrared.

[0033] In one embodiment, the transmit beam and the return beam are narrow-band near infrared wavelengths.

[0034] In one embodiment, the first polarization orientation is orthogonal to the second polarization orientation.

[0035] In one embodiment, the return beam is a transmit beam reflected from a target.

[0036] Embodiments of the present disclosure include an autonomous vehicle control system for an autonomous vehicle. The autonomous vehicle control system includes a light detection and ranging (LIDAR) device comprising one or more LIDAR pixels. At least one of the one or more LIDAR pixels includes a transmitting optical antenna and a receiving optical antenna, wherein the transmitting optical antenna is configured to emit a transmit beam. The receiving optical antenna includes a first single polarization grating coupler rotated +45 degrees relative to the transmitting optical antenna, wherein the first single polarization grating coupler is configured to detect a first polarization orientation of a return beam. The receiving optical antenna includes a second single polarization grating coupler rotated -45 degrees relative to the transmitting optical antenna, wherein the second single polarization grating coupler is configured to detect a second polarization orientation of the return beam. The LIDAR system includes a first receiver configured to generate a first electrical signal in response to receiving the first polarization orientation of the return beam and a first local oscillator signal from the receiving optical antenna. The LIDAR system also includes a second receiver configured to generate a second electrical signal in response to receiving the second polarization orientation of the return beam and a second local oscillator signal from the receiving optical antenna. The LIDAR system includes one or more processors configured to control an autonomous vehicle in response to the first electrical signal and the second electrical signal.

[0037] In one embodiment, the first single polarization grating coupler is configured to couple a first polarization orientation of the return beam to the first receiver, and the second single polarization grating coupler is configured to couple a second polarization orientation of the return beam to the second receiver.

[0038] In one embodiment, the first single polarization grating coupler is rotated relative to the second single polarization grating coupler.

[0039] In one embodiment, the transmit optical antenna includes a two-dimensional (2D) polarization grating coupler.The transmit beam includes a first polarization orientation and a second polarization orientation.

[0040] Embodiments of the present disclosure include an autonomous vehicle. The autonomous vehicle includes a light detection and ranging (LIDAR) sensor. The LIDAR sensor includes a transmitting optical antenna and a receiving optical antenna. The transmitting optical antenna is configured to emit a transmit beam. The receiving optical antenna includes a first single polarization grating coupler rotated +45 degrees relative to the transmitting optical antenna, wherein the first single polarization grating coupler is configured to detect a first polarization orientation of a return beam. The receiving optical antenna includes a second single polarization grating coupler rotated -45 degrees relative to the transmitting optical antenna, wherein the second single polarization grating coupler is configured to detect a second polarization orientation of the return beam. The LIDAR sensor includes a first receiver configured to generate a first signal in response to receiving the first polarization orientation of the return beam and a first local oscillator signal from the receiving optical antenna. The LIDAR sensor includes a second receiver configured to generate a second signal in response to receiving the second polarization orientation of the return beam and a second local oscillator signal from the receiving optical antenna. The LIDAR sensor includes one or more processors configured to control the autonomous vehicle in response to the first and second signals.

[0041] In one embodiment, the transmit beam and the return beam are narrow-band near infrared wavelengths.

[0042] In one embodiment, the transmit beam and the return beam are narrow-band near infrared wavelengths.

[0043] In one embodiment, the transmit optical antenna includes a two-dimensional (2D) polarization grating coupler.The transmit beam includes a first polarization orientation and a second polarization orientation.

[0044] Embodiments of the present disclosure include a light detection and ranging (LIDAR) system. The LIDAR system includes one or more LIDAR pixels. At least one of the one or more LIDAR pixels includes a transmitting optical antenna and a receiving optical antenna, the transmitting optical antenna being configured to emit a transmit beam. The receiving optical antenna includes a first grating coupler having a first rotation angle relative to the transmitting optical antenna, wherein the first grating coupler is configured to detect a return beam corresponding to the transmit beam reflected from a target. The receiving optical antenna includes a second grating coupler having a second rotation angle relative to the transmitting optical antenna, wherein the second grating coupler is configured to detect the return beam. At least one LIDAR pixel includes a first receiver configured to generate a first signal in response to the return beam detected by the first grating coupler and a first local oscillator signal; and a second receiver configured to generate a second signal in response to the return beam detected by the second grating coupler and the second local oscillator signal.

[0045] In one embodiment, the first rotation angle of the first grating coupler is orthogonal to the second rotation angle of the second grating coupler.

[0046] In one embodiment, the first grating coupler is configured to detect a first polarization orientation of the return beam, and the second grating coupler is configured to detect a second polarization orientation of the return beam.

[0047] In one embodiment, the first polarization orientation of the return beam is orthogonal to the second polarization orientation of the return beam.

[0048] In one embodiment, the first local oscillator signal has a first polarization orientation and the second local oscillator signal has a second polarization orientation.

[0049] In one embodiment, the first grating coupler comprises a single polarization grating coupler rotated by +45 degrees relative to the transmitting light antenna, and the second grating coupler comprises a single polarization grating coupler rotated by -45 degrees relative to the transmitting light antenna.

[0050] In one embodiment, a transmit optical antenna is coupled to a first waveguide configured to emit a transmit beam with a first polarization orientation and a second waveguide configured to emit a transmit beam with a second polarization orientation.

[0051] In one embodiment, the transmit optical antenna includes a two-dimensional (2D) polarization grating coupler.The transmit beam includes a first polarization orientation and a second polarization orientation.

[0052] In one embodiment, the first local oscillator signal and the second local oscillator signal have the same wavelength as the return beam.

[0053] In one embodiment, the transmit beam is infrared and the return beam is infrared.

[0054] In one embodiment, the transmit beam and the return beam are narrow-band near infrared wavelengths.

[0055] Embodiments of the present disclosure include an autonomous vehicle control system for an autonomous vehicle, the autonomous vehicle control system including a light detection and ranging (LIDAR) device comprising one or more LIDAR pixels. At least one of the one or more LIDAR pixels includes a transmitting optical antenna and a receiving optical antenna, the transmitting optical antenna configured to emit a transmit beam. The receiving optical antenna includes a first grating coupler having a first rotation angle relative to the transmitting optical antenna, wherein the first grating coupler is configured to detect a return beam corresponding to the transmit beam reflected from a target. The receiving optical antenna includes a second grating coupler having a second rotation angle relative to the transmitting optical antenna, wherein the second grating coupler is configured to detect the return beam. At least one pixel includes a first receiver configured to generate a first signal in response to the return beam detected by the first grating coupler and a first local oscillator signal. At least one pixel includes a second receiver configured to generate a second signal in response to the return beam detected by the second grating coupler and the second local oscillator signal.

[0056] In one embodiment, the first rotation angle of the first grating coupler is orthogonal to the second rotation angle of the second grating coupler.

[0057] In one embodiment, the first grating coupler is configured to detect a first polarization orientation of the return beam, and the second grating coupler is configured to detect a second polarization orientation of the return beam.

[0058] In one embodiment, the first polarization orientation of the return beam is orthogonal to the second polarization orientation of the return beam.

[0059] In one embodiment, the first local oscillator signal has a first polarization orientation and the second local oscillator signal has a second polarization orientation.

[0060] In one embodiment, the first grating coupler comprises a single polarization grating coupler rotated +45 degrees relative to the transmit optical antenna; and the second grating coupler comprises a single polarization grating coupler rotated -45 degrees relative to the transmit optical antenna.

[0061] Embodiments of the present disclosure include an autonomous vehicle. The autonomous vehicle includes a light detection and ranging (LIDAR) sensor. The LIDAR sensor includes a transmitting optical antenna configured to emit a transmit beam. The LIDAR sensor includes a receiving optical antenna. The receiving optical antenna includes a first grating coupler having a first rotation angle relative to the transmitting optical antenna, wherein the first grating coupler is configured to detect a return beam corresponding to the transmit beam reflected from a target. The receiving optical antenna includes a second grating coupler having a second rotation angle relative to the transmitting optical antenna, wherein the second grating coupler is configured to detect the return beam. The LIDAR sensor includes a first receiver configured to generate a first signal in response to the return beam detected by the first grating coupler and a first local oscillator signal. The LIDAR sensor includes a second receiver configured to generate a second signal in response to the return beam detected by the second grating coupler and the second local oscillator signal.

[0062] In one embodiment, the first grating coupler is configured to detect a first polarization orientation of the return beam, the second grating coupler is configured to detect a second polarization orientation of the return beam, and the first polarization orientation of the return beam is orthogonal to the second polarization orientation of the return beam. BRIEF DESCRIPTION OF THE DRAWINGS

[0063] Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

[0064] Figure 1A A LIDAR system including LIDAR pixels according to an embodiment of the present disclosure is illustrated.

[0065] Figure 1B An example coherent receiver according to an embodiment of the present disclosure is illustrated.

[0066] Figure 2 A LIDAR system including a LIDAR pixel having a two-dimensional (2D) polarization beam-splitting grating coupler as a receiving optical antenna according to an embodiment of the present disclosure is illustrated.

[0067] Figure 3 A LIDAR system including a LIDAR pixel having a 2D polarization grating coupler as a transmitting optical antenna according to an embodiment of the present disclosure is illustrated.

[0068] Figure 4A A block diagram illustrating an example of a system environment for an autonomous vehicle according to an embodiment of the present disclosure is illustrated.

[0069] Figure 4BA block diagram illustrating an example of a system environment for an autonomous commercial truck vehicle according to an embodiment of the present disclosure is illustrated.

[0070] Figure 4C A block diagram illustrating an example of a system environment for an autonomous commercial truck vehicle according to an embodiment of the present disclosure is illustrated.

[0071] Figure 4D A block diagram illustrating an example of a system environment for an autonomous commercial truck vehicle according to an embodiment of the present disclosure is illustrated. DETAILED DESCRIPTION

[0072] Embodiments of LIDAR pixels with dual polarization receiving optical antennas are described herein. The LIDAR pixel may include one or more modules, one or more integrated chips, or one or more circuits. Additionally, the LIDAR pixel may be implemented as a single packaged chip or as a modular design such that the LIDAR pixel includes multiple packaged chips. In the following description, numerous specific details are set forth to provide a thorough understanding of the embodiments. However, one skilled in the relevant art will recognize that the technology described herein may be practiced without one or more of the specific details, or using other methods, components, materials, and the like. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects.

[0073] References throughout this specification to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearance of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0074] Throughout this specification, various terms are used. These terms should be given their ordinary meanings in the art from which they are derived, unless specifically defined herein or the context in which they are used clearly indicates otherwise. For the purposes of this disclosure, the term "autonomous vehicle" includes vehicles having autonomous features at any level of autonomy as defined in SAE International Standard J3016.

[0075] In aspects of the present disclosure, visible light can be defined as light having a wavelength range of approximately 380 nm to 700 nm. Non-visible light can be defined as light having wavelengths outside the visible light range, such as ultraviolet light and infrared light. Infrared light having a wavelength range of approximately 700 nm to 1 mm includes near-infrared light. In aspects of the present disclosure, near-infrared light can be defined as light having a wavelength range of approximately 700 nm to 1600 nm.

[0076] Frequency-modulated continuous wave (FMCW) LIDAR directly measures the range and velocity of an object by directing a frequency-modulated beam of light at it. The light reflected from the object is combined with a tapped version of the beam. Once corrected for the Doppler shift that requires a second measurement, the resulting beat tone has a frequency proportional to the object's distance from the LIDAR system. These two measurements, which may or may not be performed simultaneously, provide both range and velocity information.

[0077] Embodiments of the present disclosure include a LIDAR device comprising a LIDAR pixel having a transmitting optical antenna, a receiving optical antenna, a first receiver, and a second receiver. The receiving optical antenna is a dual-polarization optical receiving antenna that detects two different polarizations (e.g., orthogonal polarization orientations) of a return beam. The first receiver generates a first signal in response to receiving a first polarization orientation of the return beam detected by the receiving optical antenna, and the second receiver generates a second signal in response to receiving a second polarization orientation of the return beam detected by the receiving optical antenna. Detecting the two different polarization orientations of the return beam can increase the signal-to-noise ratio (SNR) of the detected return beam and thereby increase the imaging quality of the LIDAR system. Additionally, detecting the two different polarization orientations of the return beam can allow the LIDAR system to detect additional information about the external environment, such as polarization-dependent surface materials of objects / targets in the external environment of the LIDAR system. In combination Figures 1A to 4D These and other embodiments are described in further detail.

[0078] Figure 1A FIG2 illustrates a LIDAR system 100 including a LIDAR pixel 199 according to an embodiment of the present disclosure. In some embodiments, the LIDAR pixel 199 includes a transmitting optical antenna 105, a receiving optical antenna 110, a first coherent receiver 121, and a second coherent receiver 126. However, the present invention is not limited to Figure 1A The specific LIDAR pixel architecture shown in . The LIDAR pixel can be implemented using any suitable chip design architecture. For example, the transmit and receive optical antennas can be implemented as a single module or a single integrated chip, or as separate modules or chips. As another example, the first and second coherent receivers can be implemented as a single module or a single integrated chip, or as separate modules or chips. The transmit optical antenna 105 is configured to emit a transmit beam. The transmit beam can be an infrared transmit beam. The transmit beam can be a near infrared transmit beam. The transmit beam can be a single defined polarization orientation. In Figure 1A, the transmit optical antenna 105 is illustrated as a single polarization output coupler and can transmit a transmit beam in response to receiving a transmit signal 101 through the waveguide 103. The transmit signal 101 can be generated by a laser, and the transmit beam emitted by the transmit optical antenna 105 can have a very narrow linewidth (e.g., 1 nm or less).

[0079] In some embodiments, the receiving optical antenna 110 is a dual polarization receiving optical antenna configured to detect a first polarization orientation of a return beam and a second polarization orientation of the return beam. The return beam is a reflection of the transmit beam reflected from a target in the external environment of the LIDAR system 100. The first polarization orientation may be orthogonal to the second polarization orientation. Figure 1A , the receiving optical antenna 110 includes a first single polarization grating coupler 111 and a second single polarization grating coupler 116. The first single polarization grating coupler 111 is configured to couple the first polarization orientation of the return beam to the first coherent receiver 121 through the waveguide 112. The second single polarization grating coupler 116 is configured to couple the second polarization orientation of the return beam to the second coherent receiver 126 through the waveguide 117.

[0080] In some embodiments, the first single polarization grating coupler 111 is rotated relative to the second single polarization grating coupler 116. Figure 1A In the specific illustrated embodiment, the first single polarization grating coupler 111 is rotated 90 degrees relative to the second single polarization grating coupler 116. The illustrated single polarization output coupler of the transmitting optical antenna 105 is rotated relative to the first single polarization grating coupler 111 and the second single polarization grating coupler 116. Figure 1A , the first single polarization grating coupler 111 is rotated by +45 degrees relative to the transmitting optical antenna 105 , and the second single polarization grating coupler 116 is rotated by −45 degrees relative to the transmitting optical antenna 105 .

[0081] In some embodiments, the first coherent receiver 121 is configured to generate a first signal 123 in response to receiving the first polarization orientation of the return beam and a first local oscillator signal 131. The first local oscillator signal 131 may be an optical signal having a first polarization orientation. Figure 1A , the first polarization orientation of the return beam is received by the first coherent receiver 121 from the first single polarization grating coupler 111 through the waveguide 112, and the first local oscillator signal 131 is received by the first coherent receiver 121 through the waveguide 132. The first signal 123 can be an electrical signal provided to the processing logic 150 through the communication channel 122.

[0082] In some embodiments, the second coherent receiver 126 is configured to generate a second signal 128 in response to receiving the second polarization orientation of the return beam and the second local oscillator signal 136. The second local oscillator signal 136 can be an optical signal having a second polarization orientation. Figure 1A , the second polarization orientation of the return beam is received by the second coherent receiver 126 from the second single polarization grating coupler 116 via waveguide 117, and the second local oscillator signal 136 is received by the second coherent receiver 126 via waveguide 137. The second signal 128 can be an electrical signal provided to the processing logic 150 via the communication channel 127.

[0083] The processing logic 150 is configured to generate an image 155 in response to receiving the first signal 123 and the second signal 128 from the first coherent receiver 121 and the second coherent receiver 126, respectively. The LIDAR system 100 may include an array of LIDAR pixels 199 configured to provide the first signal (e.g., signal 123) and the second signal (e.g., signal 128) to the processing logic 150. In this context, the processing logic 150 may generate the image 155 in response to the first signal and the second signal received by the processing logic 150 via a plurality of LIDAR pixels 199 in the array of LIDAR pixels.

[0084] In operation, a transmit signal 101 can be emitted by a transmit optical antenna 105 into free space as a transmit beam. The transmit beam can propagate through one or more lenses and be deflected by a rotating mirror, and then propagate through the external environment until it encounters an object / target. A portion of the transmit beam that encounters the object / target is reflected back to the LIDAR system 100 and LIDAR pixel 199 as a return beam. The return beam can reflect from the rotating mirror and propagate through one or more lenses, but is offset relative to the transmit optical antenna 105 due to the time difference in the mirror's rotation. To compensate for this offset, the receive optical antenna 110 can be offset from the transmit optical antenna 105 by an offset dimension 191.

[0085] Figure 1BAn example coherent receiver 171 is illustrated in accordance with an embodiment of the present disclosure. For example, the example coherent receiver 171 can be used as the coherent receiver 121 or 126. The coherent receiver 171 includes an optical mixer 152, a return beam port 154, a local oscillator port 158, and an output port 162. According to one embodiment, the optical mixer 152 is configured to combine the return beam signal RB with the local oscillator signal LO to generate an output signal OUT. For example, the optical mixer 152 can be coupled to receive the return beam signal RB from the waveguide 112 or the waveguide 117, and the waveguide 156 provides the return beam signal to the optical mixer 152. For example, the optical mixer 152 can be coupled to receive the local oscillator signal LO from the waveguide 132 or 137, and the waveguide 160 provides the local oscillator signal LO to the optical mixer 152. The optical mixer 152 can combine the input signals to generate a plurality of combined output signals OUT1 and OUT2. 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 an output signal OUT. Output signal OUT can be an electrical signal. Output signal OUT can be a beat signal representing the range and / or velocity of one or more objects in the environment of the LIDAR system. For example, communication channel 122 or 127 can be coupled to output port 162.

[0086] Figure 2 FIG2 illustrates a LIDAR system 200 including a LIDAR pixel 299 according to an embodiment of the present disclosure. The LIDAR pixel 299 includes a transmitting optical antenna 205, a receiving optical antenna 210, a first coherent receiver 221, and a second coherent receiver 226. Figure 2 , the receiving optical antenna 210 of the LIDAR pixel 299 is shown as a two-dimensional (2D) polarization beam splitting grating coupler. The 2D polarization beam splitting grating coupler is configured to couple a first polarization of the return beam to a first coherent receiver 221 and a second polarization of the return beam to a second coherent receiver 226.

[0087] The transmitting optical antenna 205 is configured to emit a transmitting beam. The transmitting beam may be an infrared transmitting beam. The transmitting beam may be a near infrared transmitting beam. The transmitting beam may be a single defined polarization orientation. Figure 2 , the transmit optical antenna 205 is illustrated as a single polarization output coupler and can transmit a transmit beam in response to receiving a transmit signal 201 through the waveguide 203. The transmit signal 201 can be generated by a laser, and the transmit beam emitted by the transmit optical antenna 205 can have a very narrow linewidth.

[0088] In some embodiments, the receiving optical antenna 210 is a dual-polarization receiving optical antenna configured to detect a first polarization orientation of a return beam and a second polarization orientation of the return beam. The return beam is a reflection of the transmit beam reflected from a target in the external environment of the LIDAR system 200. The first polarization orientation may be orthogonal to the second polarization orientation. The 2D polarization beam splitting grating coupler 210 is configured to couple the first polarization orientation of the return beam to the first coherent receiver 221 through the waveguide 212, and couple the second polarization orientation of the return beam to the second coherent receiver 226 through the waveguide 217. In some embodiments, Figure 1B The example coherent receiver 171 may be used as the first coherent receiver 221 and / or the second coherent receiver 226 .

[0089] In some embodiments, the first coherent receiver 221 is configured to generate a first signal 223 in response to receiving the first polarization orientation of the return beam and a first local oscillator signal 231. The first local oscillator signal 231 can be an optical signal having a first polarization orientation. Figure 2 , the first polarization orientation of the return beam is received by the first coherent receiver 221 from the 2D polarization beam splitting grating coupler 210 via the waveguide 212, and the first local oscillator signal 231 is received by the first coherent receiver 221 via the waveguide 232. The first signal 223 may be an electrical signal provided to the processing logic 250 via the communication channel 222.

[0090] In some embodiments, the second coherent receiver 226 is configured to generate a second signal 228 in response to receiving the second polarization orientation of the return beam and the second local oscillator signal 236. The second local oscillator signal 236 can be an optical signal having a second polarization orientation. Figure 2 , the second polarization orientation of the return beam is received by the second coherent receiver 226 from the 2D polarization beam splitting grating coupler 210 via the waveguide 217, and the second local oscillator signal 236 is received by the second coherent receiver 226 via the waveguide 237. The second signal 228 can be an electrical signal provided to the processing logic 250 via the communication channel 227.

[0091] The processing logic 250 is configured to generate an image 255 in response to receiving a first signal 223 and a second signal 228 from the first coherent receiver 221 and the second coherent receiver 226, respectively. The LIDAR system 200 may include an array of LIDAR pixels 299 configured to provide a first signal (e.g., signal 223) and a second signal (e.g., signal 228) to the processing logic 250. In this context, the processing logic 250 may generate the image 255 in response to the first signal and the second signal received by the processing logic 250 via a plurality of LIDAR pixels 299 in the array of LIDAR pixels.

[0092] In operation, a transmit signal 201 is emitted by a transmit optical antenna 205 as a transmit beam into free space. The transmit beam may propagate through one or more lenses and be deflected by a rotating mirror, and then propagate through the external environment until it encounters an object / target. A portion of the transmit beam that encounters the object / target is reflected back to the LIDAR system 200 and LIDAR pixel 299 as a return beam. The return beam may reflect from the rotating mirror and propagate through one or more lenses, but may be offset relative to the transmit optical antenna 205 due to the time difference in the mirror's rotation. To compensate for this offset, the receive optical antenna 210 may be offset from the transmit optical antenna 205 by an offset dimension 291.

[0093] Figure 3 A LIDAR system 300 including LIDAR pixels 399 is illustrated in accordance with an embodiment of the present disclosure. Figure 3 In an example embodiment, the LIDAR pixel 399 includes a transmit optical antenna 309, a receive optical antenna 310, a first coherent receiver 321, and a second coherent receiver 326. The transmit optical antenna 309 of the LIDAR pixel 399 is a 2D polarization grating coupler. The transmit optical antenna 309 can be configured to emit transmit beams with orthogonal polarizations. Figure 3 In the illustrated embodiment of FIG, the transmit optical antenna 309 is configured to receive a first transmit signal TX1 301 via the waveguide 302 and a second transmit signal TX2 302 via the waveguide 307. In some embodiments, the amplitude and / or phase of the first transmit signal TX1 301 and the second transmit signal TX2 302 are modulated. This additional degree of freedom with respect to the transmit beam emitted by the transmit optical antenna 309 can help provide additional information about the polarization-dependent reflectivity of the environment.

[0094] The receiving optical antenna 310 of the LIDAR pixel 399 is illustrated as a two-dimensional (2D) polarization beam splitting grating coupler. The 2D polarization beam splitting grating coupler 310 can be similar to Figure 2 Therefore, the 2D polarization beam splitting grating coupler 310 is configured to couple the first polarization of the return beam to the first coherent receiver 321 and couple the second polarization of the return beam to the second coherent receiver 326. Figure 3As shown in FIG, the first polarization orientation may be orthogonal to the second polarization orientation. The transmit beam emitted by the 2D polarization beam splitting grating coupler 310 may include the first polarization orientation and the second polarization orientation. The transmit beam may be an infrared transmit beam. The transmit beam may be a near-infrared transmit beam. The transmit signal TX1 301 and / or the transmit signal TX2 302 may be generated by a laser, and the transmit beam emitted by the transmit optical antenna 309 may have a very narrow linewidth.

[0095] In some embodiments, the receiving optical antenna 310 is a dual-polarization receiving optical antenna configured to detect a first polarization orientation of a return beam and a second polarization orientation of the return beam. The return beam is a reflection of the transmit beam reflected from a target in the external environment of the LIDAR system 300. The first polarization orientation can be orthogonal to the second polarization orientation. The 2D polarization beam splitting grating coupler 310 is configured to couple the first polarization orientation of the return beam to the first coherent receiver 321 through the waveguide 312, and couple the second polarization orientation of the return beam to the second coherent receiver 326 through the waveguide 317. In some embodiments, Figure 1A The example coherent receiver 171 may be used as the first coherent receiver 321 and / or the second coherent receiver 326 .

[0096] In some embodiments, the first coherent receiver 321 is configured to generate a first signal 323 in response to receiving the first polarization orientation of the return beam and a first local oscillator signal 331. The first local oscillator signal 331 can be an optical signal having a first polarization orientation. Figure 3 , the first polarization orientation of the return beam is received by the first coherent receiver 321 from the 2D polarization beam splitting grating coupler 310 through the waveguide 312, and the first local oscillator signal 331 is received by the first coherent receiver 321 through the waveguide 332. The first signal 323 can be an electrical signal provided to the processing logic 350 through the communication channel 322.

[0097] In some embodiments, the second coherent receiver 326 is configured to generate a second signal 328 in response to receiving the second polarization orientation of the return beam and the second local oscillator signal 336. The second local oscillator signal 336 can be an optical signal having a second polarization orientation. Figure 3 , the second polarization orientation of the return beam is received by the second coherent receiver 326 from the 2D polarization beam splitting grating coupler 310 via waveguide 317, and the second local oscillator signal 336 is received by the second coherent receiver 326 via waveguide 337. The second signal 328 can be an electrical signal provided to the processing logic 350 via the communication channel 327.

[0098] The processing logic 350 is configured to generate an image 355 in response to receiving a first signal 323 and a second signal 328 from the first coherent receiver 321 and the second coherent receiver 326, respectively. The LIDAR system 300 may include an array of LIDAR pixels 399 configured to provide a first signal (e.g., signal 323) and a second signal (e.g., signal 328) to the processing logic 350. In this context, the processing logic 350 may generate the image 355 in response to the first signal and the second signal received by the processing logic 350 via a plurality of LIDAR pixels 399 in the array of LIDAR pixels.

[0099] In operation, transmit signals 301 and 306 are emitted by transmit optical antenna 309 as a transmit beam into free space. The transmit beam can propagate through one or more lenses and be deflected by a rotating mirror, and then propagate through the external environment until it encounters an object / target. A portion of the transmit beam that encounters the object / target is reflected back to LIDAR system 300 and LIDAR pixel 399 as a return beam. The return beam can reflect from the rotating mirror and propagate through one or more lenses, but is offset relative to transmit optical antenna 309 due to the time difference in the mirror's rotation. To compensate for this offset, receive optical antenna 310 can be offset from transmit optical antenna 309 by an offset dimension 391.

[0100] 1. System environment for autonomous vehicles

[0101] Figure 4A is a block diagram illustrating an example of a system environment for an autonomous vehicle according to some implementations.

[0102] See also Figure 4A , an example autonomous vehicle 410A is shown within which the various techniques disclosed herein may be implemented. For example, vehicle 410A may include a powertrain 492 comprising a prime mover 494 powered by an energy source 496 and capable of providing power to a drivetrain 498; and a control system 480 comprising a directional control 482, a powertrain control 484, and a braking control 486. Vehicle 410A may be implemented as any number of different types of vehicles, including vehicles capable of transporting people and / or cargo and capable of navigating a variety of environments, and it will be appreciated that the components 480 through 498 described above may vary widely depending on the type of vehicle in which they are utilized.

[0103] For simplicity, the embodiments discussed below will focus on wheeled land vehicles, such as cars, vans, trucks, buses, and the like. In such embodiments, prime mover 494 may include one or more electric motors and / or internal combustion engines (among others). The energy source may include, for example, a fuel system (e.g., providing gasoline, diesel, hydrogen, etc.), a battery system, solar panels or other renewable energy sources, and / or a fuel cell system. Drivetrain 498 may include wheels and / or tires, as well as a transmission and / or any other mechanical drive components to convert the output of prime mover 494 into vehicle motion, as well as one or more brakes configured to controllably stop or slow vehicle 410A, and steering or steering components suitable for controlling the trajectory of vehicle 410A (e.g., a rack and pinion steering linkage that enables one or more wheels of vehicle 410A to pivot about a substantially vertical axis to change the angle of the wheel's plane of rotation relative to the vehicle's longitudinal axis). In some embodiments, a combination of powertrains and energy sources may be used (e.g., in the case of an electric / gasoline hybrid vehicle), and in some instances, multiple electric motors (e.g., dedicated to each wheel or axle) may be used as prime movers.

[0104] Steering control 482 may include one or more actuators and / or sensors for controlling and receiving feedback from a steering or steering assembly to enable vehicle 410A to follow a desired trajectory. Powertrain control 484 may be configured to control the output of powertrain 402, such as controlling the output power of prime mover 494, controlling the gear position of a transmission in transmission 498, and the like, thereby controlling the speed and / or direction of vehicle 410A. Braking control 416 may be configured to control one or more brakes, such as disc brakes or drum brakes coupled to the vehicle's wheels, to slow or stop vehicle 410A.

[0105] Other vehicle types, including but not limited to off-road vehicles, all-terrain or tracked vehicles, construction equipment, and the like, will necessarily utilize different powertrains, drivetrains, energy sources, directional control, powertrain control, and braking controls. Furthermore, in some embodiments, some components may be combined, for example, where directional control of the vehicle is primarily handled by varying the output of one or more prime movers. Thus, the embodiments disclosed herein are not limited to the specific application of the technology described herein to autonomous wheeled land vehicles.

[0106] Various levels of autonomous control of vehicle 410A may be implemented in a vehicle control system 420, which may include one or more processors 422 and one or more memories 424, where each processor 422 is configured to execute program code instructions 426 stored in memory 424. The processors may include, for example, a graphics processing unit (“GPU”) and / or a central processing unit (“CPU”).

[0107] Sensors 430 may include various sensors suitable for collecting information from the vehicle's surroundings for use in controlling the vehicle's operation. For example, sensors 430 may include a radar sensor 434, a lidar (light detection and ranging) sensor 436, and a 3D positioning sensor 438, such as an accelerometer, gyroscope, magnetometer, or any of a variety of satellite navigation systems, such as GPS (Global Positioning System), GLONASS (Globalnaya Navigazionnaya Sputnikovaya Sistema or Global Navigation Satellite System), BeiDou Satellite Navigation System (BDS), Galileo, a compass, and the like. 3D positioning sensor 438 can be used to determine the vehicle's position on Earth using satellite signals. Sensors 430 may include a camera 440 and / or an inertial measurement unit (IMU) 442. Camera 440 may be a single-frame or stereo camera and can record still and / or video images. IMU 442 may include multiple gyroscopes and accelerometers capable of detecting linear and rotational motion of the vehicle in three directions. One or more encoders (not shown), such as wheel encoders, may be used to monitor the rotation of one or more wheels of vehicle 410A. Each sensor 430 may output sensor data at various data rates, which may be different from the data rates of other sensors 430.

[0108] The output of sensor 430 may be provided to a set of control subsystems 450, including a positioning subsystem 452, a planning subsystem 456, a perception subsystem 454, and a control subsystem 458. Positioning subsystem 452 may perform functions such as accurately determining the position and orientation (sometimes referred to as "pose") of vehicle 410A within its surrounding environment, typically within a reference frame. As part of generating labeled autonomous vehicle data, the autonomous vehicle's position may be compared with the positions of additional vehicles in the same environment. Perception subsystem 454 may perform functions such as detecting, tracking, identifying, and / or recognizing objects within the environment surrounding vehicle 410A. Machine learning models may be used to track objects. Planning subsystem 456 may perform functions such as planning a trajectory for vehicle 410A within a timeframe, given a desired destination and static and moving objects within the environment. Machine learning may be used to plan the vehicle's trajectory. Control subsystem 458 may perform functions such as generating appropriate control signals to control various controls within vehicle control system 420 to achieve the planned trajectory of vehicle 410A. A machine learning model may be utilized to generate one or more signals to control the autonomous vehicle to achieve the planned trajectory.

[0109] Will understand, Figure 4AThe collection of components of the vehicle control system 420 illustrated in FIG is merely exemplary. In some embodiments, individual sensors may be omitted. Additionally or alternatively, in some embodiments, Figure 4A The multiple sensor types illustrated in FIG4 can be used for redundancy and / or to cover different areas around the vehicle, and other types of sensors may be used. Similarly, in other embodiments, different types and / or combinations of control subsystems may be used. Furthermore, while subsystems 452 through 458 are illustrated as separate from processor 422 and memory 424, it will be understood that in some embodiments, some or all of the functionality of subsystems 452 through 458 may be implemented using program code instructions 426 residing in one or more memories 424 and executed by one or more processors 422, and that these subsystems 452 through 458 may, in some instances, be implemented using the same processor and / or memory. The subsystems may be implemented, at least in part, using various dedicated circuit logic, various processors, various field-programmable gate arrays ("FPGAs"), various application-specific integrated circuits ("ASICs"), various real-time controllers, and the like. As described above, multiple subsystems may utilize circuitry, processors, sensors, and / or other components. Furthermore, the various components in vehicle control system 420 may be networked in various ways.

[0110] In some embodiments, vehicle 410A may also include an auxiliary vehicle control system (not shown) that may serve as a redundant or backup control system for vehicle 410A. The auxiliary vehicle control system may be capable of fully operating autonomous vehicle 410A in the event of an adverse event in vehicle control system 420, while in other embodiments, the auxiliary vehicle control system may have only limited functionality, such as executing a controlled stop of vehicle 410A in response to an adverse event detected in primary vehicle control system 420. In still other embodiments, the auxiliary vehicle control system may be omitted.

[0111] Typically, a myriad of different architectures can be used to implement Figure 4A , these architectures include various combinations of software, hardware, circuit logic, sensors, networks, etc. For example, each processor may be implemented as a microprocessor, and each memory may represent a random access memory ("RAM") device, including primary storage as well as any supplementary levels of memory, such as cache memory, non-volatile or backup memory (e.g., programmable or flash memory), read-only memory, etc. Additionally, each memory may be considered to include memory storage devices physically located elsewhere in the vehicle 410A, such as any cache memory in a processor, as well as any storage capacity used as virtual memory, such as stored on a mass storage device or another computer controller. Figure 4AOne or more of the processors illustrated in the figure or an entirely separate processor may be used to implement additional functionality in the vehicle 410A beyond the purpose of autonomous control, such as controlling the entertainment system, operating doors, lights, convenience features, etc.

[0112] In addition, for additional storage, the vehicle 410A may include one or more mass storage devices, such as a removable disk drive, a hard drive, a direct access storage device ("DASD"), an optical disk drive (e.g., a CD drive, a DVD drive, etc.), a solid-state storage drive ("SSD"), a network attached storage, a storage area network, and / or a tape drive, etc.

[0113] Additionally, the vehicle 410A may include a user interface 464 that enables the vehicle 410A to receive a plurality of inputs from and generate outputs for a user or operator, such as one or more displays, touch screens, voice and / or gesture interfaces, buttons and other tactile controls, etc. Alternatively, the user input may be received via another computer or electronic device, such as via an app on a mobile device or via a web interface.

[0114] In addition, the vehicle 410A may include one or more network interfaces, such as a network interface 462, which is suitable for communicating with one or more networks 470 (e.g., a local area network ("LAN"), a wide area network ("WAN"), a wireless network, and / or the Internet, etc.) to allow communication of information with other computers and electronic devices, including, for example, central services such as cloud services, from which the vehicle 410A receives environmental and other data for use in its autonomous control. Data collected by the one or more sensors 430 may be uploaded to a computing system 472 via the network 470 for additional processing. A timestamp may be added to each instance of vehicle data prior to uploading. Reference Figure 2 Additional processing of autonomous vehicle data by computing system 472 is described in accordance with many embodiments.

[0115] Figure 4A Each processor illustrated in FIG40A and the various additional controllers and subsystems disclosed herein typically operates under the control of an operating system and executes or otherwise relies on various computer software applications, components, programs, objects, modules, data structures, etc., as described in greater detail below. Additionally, the various applications, components, programs, objects, modules, etc. may also be executed on one or more processors in another computer coupled to the vehicle 410A via the network 470, for example, in a distributed, cloud-based, or client-server computing environment, where the processing required to implement the functionality of the computer program may be distributed across multiple computers and / or services on the network.

[0116] In general, the routines executed to implement the various embodiments described herein, whether implemented as part of an operating system or as a specific application, component, program, object, module, or sequence of instructions, or even a subset thereof, will be referred to herein as "program code." Program code may include one or more instructions that reside at various times in various memories and storage devices and, when read and executed by one or more processors, perform the steps necessary to perform the steps or elements embodying various aspects of the present disclosure. Furthermore, while the embodiments have been and will be described hereinafter in the context of fully functioning computers and systems, it will be understood that the various embodiments described herein can be distributed as program products in a variety of forms, and that the embodiments can be implemented regardless of the particular type of computer-readable medium used to actually carry out the distribution.

[0117] Examples of computer-readable media include tangible, non-transitory media such as volatile and non-volatile memory devices, floppy disks and other removable disks, solid-state drives, hard drives, magnetic tapes, and optical disks (e.g., CD-ROMs, DVDs, etc.), among others.

[0118] In addition, the various program codes described hereinafter can be identified based on the application in which the program code is implemented in its inherent specific embodiment. However, it should be understood that any specific program nomenclature hereinafter is used only for convenience, and therefore the present disclosure should not be limited to use in any specific application that is only identified and / or implied by such nomenclature. In addition, given computer programs can be organized into the usual countless ways of routines, processes, methods, modules, objects, etc., and the various ways in which program functions can be distributed among the various software layers (e.g., operating systems, libraries, APIs, applications, applets, etc.) that reside in typical computers, and it should be understood that the present disclosure is not limited to the specific organization and distribution of the program functions described herein.

[0119] Figure 4A The environment shown in the figure 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.

[0120] 2. Coherent LIDAR for automotive applications

[0121] Trucks can include lidar systems (e.g. Figure 4AVehicle control system 420 in FIG. ). In some embodiments, a lidar system can use frequency modulation to encode an optical signal and use optics to scatter the coded optical signal into free space. For example, a frequency modulated (FM) lidar system can determine the position of an object and / or accurately measure the velocity of an object using the Doppler effect by detecting the frequency difference between the coded optical signal and the return signal reflected from the object. FM lidar systems can use continuous waves (referred to as "FMCW lidar" or "coherent FMCW lidar") or quasi-continuous waves (referred to as "FMQW lidar"). In some embodiments, a lidar system can use phase modulation (PM) to encode an optical signal and use optics to scatter the coded optical signal into free space.

[0122] For automotive and / or commercial truck applications, FM or PM lidar systems can offer significant advantages over conventional lidar systems. First, in some instances, an object (e.g., a pedestrian wearing dark clothing) may have low reflectivity, reflecting only a small amount (e.g., 10% or less) of the light striking the object back to the FM or PM lidar system's sensor (e.g., Figure 4A In other examples, an object (e.g., a shiny road sign) may have a high reflectivity (e.g., greater than 10%), reflecting a significant amount of light striking the object back toward the sensor of the FM lidar system.

[0123] Regardless of the reflectivity of the object, the FM lidar system can detect (e.g., classify, distinguish, discover, etc.) objects at a greater distance (e.g., twice) than traditional lidar systems. For example, the FM lidar system can detect low-reflectivity objects at a distance of 300 meters and high-reflectivity objects at a distance of 400 meters.

[0124] To achieve this improvement in detection capabilities, FM lidar systems can use sensors (e.g. Figure 4A430 in FIG. ). In some embodiments, these sensors can be single-photon sensitive, meaning they can detect the smallest possible amount of light. While FM lidar systems can use infrared wavelengths (e.g., 950 nm, 1550 nm, etc.) in some applications, they 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 an FM or PM lidar system within the infrared wavelength, the FM or PM lidar system can broadcast more intense light pulses or beams while meeting eye safety standards. Conventional lidar systems are typically not single-photon sensitive and / or operate only in the near-infrared wavelength, requiring them to limit their light output (and distance detection capabilities) for eye safety reasons.

[0125] Therefore, by detecting objects at greater distances, FM lidar systems can have more time to react to unexpected obstacles. In fact, even a few milliseconds of extra time can improve safety and comfort, especially for heavy vehicles (such as commercial trucks) driving at highway speeds.

[0126] Another advantage of FM lidar systems is that they can instantly provide accurate velocity for each data point. In some embodiments, velocity measurement is accomplished using the Doppler effect, which shifts the frequency of light received from an object based on at least one of the velocity in a radial direction (e.g., the direction vector between the detected object and the sensor) or the frequency of the laser signal. For example, for speeds encountered in road conditions less than 100 meters per second (m / s), this shift at a wavelength of 1550 nanometers (nm) amounts to a frequency shift of less than 130 megahertz (MHz). This frequency shift is so small that it is difficult to detect directly in the optical domain. However, by using coherent detection in FMCW, PMCW, or FMQW lidar systems, the signal can be converted to the RF domain, allowing the frequency shift to be calculated using various signal processing techniques. This enables autonomous vehicle control systems to process incoming data more quickly.

[0127] Instantaneous velocity calculations also make it easier for FM lidar systems to identify distant or sparse data points as objects and / or to track how these objects are moving over time. For example, FM lidar sensors (e.g., Figure 4A A sensor 430 in the image sensor 430 may receive only a few returns (e.g., hits) on an object 300 meters away, but if those returns give interesting velocity values ​​(e.g., moving toward the vehicle at >70 mph), the FM lidar system and / or autonomous vehicle control system can determine a corresponding weight for the probability of being associated with the object.

[0128] Faster identification and / or tracking by the FM lidar system gives the autonomous vehicle control system more time to maneuver the vehicle. A better understanding of how fast an object is moving also allows the autonomous vehicle control system to plan a better response.

[0129] Another advantage of FM lidar systems is that they exhibit less static interference than traditional lidar systems. Specifically, traditional lidar systems, designed to be sensitive to light, typically perform poorly in bright sunlight. These systems are also susceptible to crosstalk (e.g., when sensors are confused by each other's light pulses or beams) and self-interference (e.g., when a sensor is confused by its own previous light pulses or beams). To overcome these shortcomings, vehicles using traditional lidar systems typically require additional hardware, complex software, and / or more computing power to manage this "noise."

[0130] In contrast, FM lidar systems do not suffer from these types of issues because each sensor is specifically designed to respond only to its own light characteristics (e.g., light beam, light wave, light pulse). If the returning light does not match the timing, frequency, and / or wavelength of the originally emitted light, the FM sensor can filter out (e.g., remove, ignore, etc.) that data point. As a result, FM lidar systems produce (e.g., generate, derive, etc.) more accurate data with less hardware or software requirements, enabling safer and smoother driving.

[0131] Finally, FM lidar systems are more scalable than traditional lidar systems. As more autonomous vehicles (e.g., cars, commercial trucks, etc.) appear on the road, vehicles powered by FM lidar systems may not have to deal with interference issues caused by sensor crosstalk. Furthermore, FM lidar systems use less peak optical power than traditional lidar sensors. As a result, some or all of FM lidar's optical components can be manufactured on a single chip, which has its own benefits, as discussed in this article.

[0132] 3. Commercial Trucks

[0133] Figure 4Bis a block diagram illustrating an example of a system environment for an autonomous commercial truck vehicle, according to some embodiments. Environment 400B includes a commercial truck 402B for hauling freight 406B. In some embodiments, commercial truck 402B may include a vehicle configured for long-haul freight transport, regional freight transport, intermodal freight transport (i.e., where a road-based vehicle is used as one of multiple modes of transport to move freight), and / or any other road-based freight transport application. Commercial truck 402B may be a flatbed truck, a refrigerated truck (e.g., a freezer truck), a ventilated truck (e.g., a dry van), a moving truck, etc. Freight 406B may be merchandise and / or products. Commercial truck 402B may include a trailer for carrying freight 406B, such as a flatbed, a lowbed, a step-type trailer, an extendable flatbed, a sidecar, etc.

[0134] Environment 400B includes object 410B (in Figure 4B is shown as another vehicle in the figure), which is within a distance of 30 meters or less from the truck.

[0135] Commercial truck 402B may include lidar system 404B (e.g., Figure 4A FM lidar system, vehicle control system 420) for determining the distance to object 410B and / or measuring the speed of object 410B. Figure 4B One lidar system 404B is shown mounted on the front of commercial truck 402B, but the number of lidar systems and the areas where the lidar systems are mounted on the commercial truck are not limited to a specific number or area. Commercial truck 402B can include any number of lidar systems 404B (or components thereof, such as sensors, modulators, coherent signal generators, etc.) mounted on any area of ​​commercial truck 402B (e.g., the front, rear, sides, top, bottom, underside, and / or bottom) to facilitate detection of objects in any free space relative to commercial truck 402B.

[0136] As shown, lidar system 404B in environment 400B may be configured to detect objects (eg, another vehicle, a bicycle, a tree, a street sign, a pothole, etc.) at a short distance (eg, 30 meters or less) from commercial truck 402B.

[0137] Figure 4C is a block diagram illustrating an example of a system environment for an autonomous commercial truck vehicle in accordance with some embodiments. Environment 400C includes the same components included in environment 400B (e.g., commercial truck 402B, cargo 406B, lidar system 404B, etc.).

[0138] Environment 400C includes object 410C (in Figure 4C 400C) is within a range of (i) greater than 30 meters and (ii) equal to or less than 150 meters from the commercial truck 402B. As shown, the lidar system 404B in the environment 400C can be configured to detect objects (e.g., another vehicle, a bicycle, a tree, a street sign, a pothole, etc.) at a distance (e.g., 100 meters) from the commercial truck 402B.

[0139] Figure 4D is a block diagram illustrating an example of a system environment for an autonomous commercial truck vehicle, according to some embodiments. Environment 400D includes the same components included in environment 400B (e.g., commercial truck 402B, cargo 406B, lidar system 404B, etc.).

[0140] Environment 400D includes object 410D (in Figure 4D 4 ) is within a range of more than 150 meters from commercial truck 402B. As shown, lidar system 404B in environment 400D can be configured to detect objects (e.g., another vehicle, a bicycle, a tree, a street sign, a pothole, etc.) at a distance (e.g., 300 meters) from commercial truck 402B.

[0141] In commercial truck applications, due to the increased weight and correspondingly longer stopping distances required for such vehicles, it is important to effectively detect objects at all ranges. Due to the advantages described above, FM lidar systems (e.g., FMCW and / or FMQW systems) or PM lidar systems are well suited for commercial truck applications. As a result, commercial trucks equipped with such systems can have an enhanced ability to safely move both people and cargo across short or long distances, thereby improving not only the safety of the commercial truck but also the safety of surrounding vehicles. In various embodiments, such FM or PM lidar systems can be used in the following: semi-autonomous applications, in which the commercial truck has a driver and some functions of the commercial truck are operated autonomously using the FM or PM lidar system; or fully autonomous applications, in which the commercial truck is operated entirely by the FM or lidar system alone or in combination with other vehicle systems.

[0142] 4. Continuous Wave Modulation and Quasi-Continuous Wave Modulation

[0143] In lidar systems using CW modulation, the modulator modulates the laser continuously. For example, if the modulation period is 10 seconds, the input signal is modulated for the entire 10 seconds. In contrast, in lidar systems using quasi-CW modulation, the modulator modulates the laser to have both active and inactive portions. For example, in a 10-second period, the modulator modulates the laser only for 8 seconds (sometimes called the "active portion") but not for 2 seconds (sometimes called the "inactive portion"). By doing this, the lidar system can reduce power consumption during these 2 seconds because the modulator does not have to provide a continuous signal.

[0144] In frequency-modulated continuous-wave (FMCW) lidar systems for automotive applications, it can be beneficial to operate the lidar system using quasi-CW modulation, where FMCW measurement and signal processing methods are used, but the optical signal is not constantly in the on state (e.g., enabled, powered, transmitting, etc.). In some embodiments, the quasi-CW modulation can have a duty cycle equal to or greater than 1% and up to 50%. If the energy in the off state (e.g., disabled, powered off, etc.) can be consumed during the actual measurement time, there can be an improvement in the signal-to-noise ratio (SNR) and / or a reduction in the signal processing requirements to coherently integrate all the energy over a longer time scale.

[0145] The term "processing logic" in this disclosure may include one or more processors, microprocessors, multi-core processors, application-specific integrated circuits (ASICs), and / or field-programmable gate arrays (FPGAs) to perform the operations disclosed herein. In some embodiments, a memory (not shown) is integrated into the processing logic to store instructions for performing the operations and / or store data. The processing logic may also include analog or digital circuitry to perform the operations according to embodiments of the present disclosure.

[0146] The "memory" or "memories" described in this disclosure may include one or more volatile or non-volatile memory architectures. The "memory" or "memories" may be removable and non-removable media implemented in any method or technology for storage of information, such as computer-readable instructions, data structures, program modules, or other data. Example memory technologies may include RAM, ROM, EEPROM, flash memory, CD-ROM, digital versatile disks (DVDs), high-definition multimedia / data storage disks or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information for access by a computing device.

[0147] The network may include any network or network system, such as, but not limited to, a peer-to-peer network; a local area network (LAN); a wide area network (WAN); a public network such as the Internet; a private network; a cellular network; a wireless network; a wired network; a combined wireless and wired network; and a satellite network.

[0148] The communication channel may include or be routed through one or more wired or wireless communications utilizing IEEE 802.11 protocols, Bluetooth, SPI (Serial Peripheral Interface), I 2 C (Interconnected Circuit Bus), USB (Universal Serial Port), CAN (Controller Area Network), cellular data protocols (e.g., 3G, 4G, LTE, 5G), optical communications networks, Internet Service Providers (ISPs), peer-to-peer networks, local area networks (LANs), wide area networks (WANs), public networks (e.g., the "Internet"), private networks, satellite networks, or other.

[0149] The computing device may include a desktop computer, a laptop computer, a tablet computer, a phablet, a smartphone, a feature phone, a server computer, or others. The server computer may be located remotely in a data center or stored locally.

[0150] The above processes are described in terms of computer software and hardware. The described techniques may constitute machine-executable instructions embodied in a tangible or non-transitory machine (e.g., computer) readable storage medium that, when executed by a machine, causes the machine to perform the described operations. Additionally, these processes may be embodied in hardware, such as an application-specific integrated circuit ("ASIC") or other hardware.

[0151] Tangible, non-transitory, machine-readable storage media include any mechanism that provides (i.e., stores) information in a form accessible by a machine (e.g., a computer, a network device, a personal digital assistant, a manufacturing tool, any device having one or more processors, etc.). For example, machine-readable storage media include recordable and non-recordable media (e.g., read-only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.).

[0152] The above description of the illustrated embodiments of the present invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Although specific embodiments and examples of the invention are described herein for illustrative purposes, as those skilled in the relevant art will recognize, various modifications are possible within the scope of the invention.

[0153] These modifications can be made to the invention in light of the foregoing detailed description. The terms used in the appended claims should not be construed to limit the invention to the specific embodiments disclosed in the specification. Rather, the scope of the invention is to be determined entirely by the appended claims, which are to be construed in accordance with established doctrines of claim interpretation.

Claims

1. A light detection and ranging (LIDAR) system comprising: One or more LIDAR pixels, wherein at least one LIDAR pixel of the one or more LIDAR pixels comprises: a transmit optical antenna configured to emit a transmit beam; A receiving optical antenna, the receiving optical antenna comprising: a first single polarization grating coupler rotated +45 degrees relative to the transmit optical antenna, wherein the first single polarization grating coupler is configured to detect a first polarization orientation of a return beam, and a second single polarization grating coupler rotated by -45 degrees relative to the transmit optical antenna, wherein the second single polarization grating coupler is configured to detect a second polarization orientation of the return beam; a first receiver configured to generate a first signal in response to receiving the first polarization orientation of the return beam from the receive optical antenna and a first local oscillator signal having the first polarization orientation; and A second receiver is configured to generate a second signal in response to receiving the second polarization orientation of the return beam from the receive optical antenna and a second local oscillator signal having the second polarization orientation.

2. The LIDAR system according to claim 1, wherein: The first single polarization grating coupler is offset from the second single polarization grating coupler.

3. The LIDAR system according to any one of claims 1 or 2, wherein: The first single polarization grating coupler is rotated relative to the second single polarization grating coupler.

4. The LIDAR system according to any one of claims 1 to 3, wherein: The first single polarization grating coupler is rotated approximately 90 degrees relative to the second single polarization grating coupler.

5. The LIDAR system according to any one of claims 1 to 4, wherein: The single polarization output coupler of the transmit optical antenna is rotated relative to the first single polarization grating coupler and the second single polarization grating coupler.

6. The LIDAR system according to any one of claims 1 to 5, wherein: The transmit optical antenna comprises a two-dimensional (2D) polarization grating coupler, and wherein the transmit beam comprises the first polarization orientation and the second polarization orientation.

7. The LIDAR system according to any one of claims 1 to 6, wherein: The first local oscillator signal and the second local oscillator signal have the same wavelength as the return beam.

8. The LIDAR system according to any one of claims 1 to 7, wherein: The transmit beam has the first polarization orientation.

9. The LIDAR system according to any one of claims 1 to 8, wherein: The transmit beam is infrared, and wherein the return beam is infrared.

10. The LIDAR system according to any one of claims 1 to 9, wherein: The transmit beam and the return beam are narrow-band near infrared wavelengths.

11. The LIDAR system according to any one of claims 1 to 10, wherein: The first polarization orientation is orthogonal to the second polarization orientation.

12. The LIDAR system according to any one of claims 1 to 11, wherein: The return beam is the transmit beam reflected from a target.

13. An autonomous vehicle control system for an autonomous vehicle, comprising a LIDAR system according to any one of claims 1 to 12.

14. The autonomous vehicle control system of claim 13, further comprising one or more processors configured to control the autonomous vehicle in response to the first electrical signal and the second electrical signal.

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

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