Lidar pixel with dual-polarization receive 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 receive optical antenna is configured to detect (i) a first polarization orientation of a return beam and (ii) a second polarization orientation of the return beam.

Description

[0001] Related applications

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

[0003] Frequency-modulated continuous wave (FMCW) optical detection and ranging (LIDAR) directly measures the range and speed of an object by emitting a frequency-modulated beam of light and detecting the returned signal. The automotive industry is currently developing autonomous features for controlling vehicles under specific conditions. 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 sense 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 this disclosure include an optical detection and ranging (LIDAR) system comprising one or more LIDAR pixels, and at least one of the one or more LIDAR pixels comprising 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 the 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 beamsplitter coupler configured to couple a first polarization orientation of the returning beam to a first receiver and to couple a second polarization orientation of the returning beam to a second receiver.

[0006] In one embodiment, the receive 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 a first receiver. The second single-polarization grating coupler is configured to couple a second polarization orientation of the return beam to a 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 about 90 degrees relative to the second single-polarization grating coupler.

[0010] In one embodiment, a 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.

[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 a 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 narrowband 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 the 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 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 receive optical antenna is configured to detect (i) a first polarization orientation of a return beam and (ii) a second polarization orientation of the return beam. The first receiver is configured to generate a first electrical signal in response to receiving the first polarization orientation of the return beam from the receive optical antenna and a first local oscillator signal. The second receiver is configured to generate a second electrical signal in response to receiving the second polarization orientation of the return beam from the receive optical antenna and a second local oscillator signal. 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 receive optical antenna comprises a two-dimensional (2D) polarization beam splitting grating coupler configured to couple the first polarization orientation of the return beam to the first receiver and configured to couple the second polarization orientation of the return beam to the second receiver.

[0020] In one embodiment, the receive optical antenna comprises a first single polarization grating coupler and a second single polarization grating coupler. The first single polarization grating coupler is configured to couple the first polarization orientation of the return beam to the first receiver. The second single polarization grating coupler is configured to couple the 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 comprises a two-dimensional (2D) polarization grating coupler and the transmit beam comprises 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 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 receive optical antenna is configured to detect (i) a first polarization orientation of a return beam and (ii) a second polarization orientation of the return beam. The first receiver is 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. The 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. 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 comprises one or more LIDAR pixels. At least one LIDAR pixel of the one or more LIDAR pixels comprises a transmit optical antenna and a receive optical antenna. The transmit optical antenna is configured to emit a transmit beam. The receive optical antenna comprises 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. The receive optical antenna comprises a second single polarization grating coupler rotated -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. The LIDAR system comprises 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. The LIDAR comprises a second receiver 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.

[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, a 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.

[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 a 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. The return beam is infrared.

[0033] In one embodiment, the transmit beam and the return beam are narrowband 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 the 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 including one or more LIDAR pixels. At least one LIDAR pixel of the one or more LIDAR pixels includes a transmit optical antenna configured to emit a transmit beam and a receive optical antenna. The receive optical antenna includes a first single-polarization grating coupler rotated +45 degrees relative to the transmit optical antenna, where the first single-polarization grating coupler is configured to detect a first polarization orientation of a return beam. The receive optical antenna includes a second single-polarization grating coupler rotated -45 degrees relative to the transmit optical antenna, where 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 from the receive optical antenna and a first local oscillator signal. The LIDAR system includes a second receiver configured to generate a second electrical signal in response to receiving the second polarization orientation of the return beam from the receive optical antenna and a second local oscillator signal. The LIDAR system includes one or more processors configured to control the 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 the first polarization orientation of the return beam to the first receiver. The second single-polarization grating coupler is configured to couple the 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 transmit optical antenna and a receive optical antenna. The transmit optical antenna is configured to emit a transmit beam. The receive optical antenna includes a first single polarization grating coupler rotated +45 degrees relative to the transmit optical antenna, where the first single polarization grating coupler is configured to detect a first polarization orientation of a return beam. The receive optical antenna includes a second single polarization grating coupler rotated -45 degrees relative to the transmit optical antenna, where 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 from the receive optical antenna and a first local oscillator signal. 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 from the receive optical antenna and a second local oscillator signal. The LIDAR sensor includes one or more processors configured to control the autonomous vehicle in response to the first signal and the second signal.

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

[0042] In one embodiment, the transmit beam and the return beam are narrowband 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 LIDAR pixel of the one or more LIDAR pixels includes: a transmit optical antenna configured to emit a transmit beam. The receive optical antenna includes a first grating coupler having a first rotation angle relative to the transmit optical antenna, where the first grating coupler is configured to detect a return beam corresponding to the transmit beam reflected from a target. The receive optical antenna includes a second grating coupler having a second rotation angle relative to the transmit optical antenna, where the second grating coupler is configured to detect the return beam. The 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 a 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 includes a single polarization grating coupler rotated +45 degrees relative to the transmit optical antenna. The second grating coupler includes a single polarization grating coupler rotated -45 degrees relative to the transmit optical antenna.

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

[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 a 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 narrowband near infrared wavelengths.

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

[0056] In one embodiment, the first angle of rotation of the first grating coupler is orthogonal to the second angle of rotation 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 transmit optical antenna configured to emit a transmit beam. The LIDAR sensor includes a receive optical antenna. The receive optical antenna includes a first grating coupler having a first rotation angle with respect to the transmit optical antenna, where the first grating coupler is configured to detect a return beam corresponding to the transmit beam reflected from a target. The receive optical antenna includes a second grating coupler having a second rotation angle with respect to the transmit optical antenna, where 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 a 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 DRAWINGS

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

[0064] FIG. 1A A LIDAR system including a LIDAR pixel is illustrated in accordance with an embodiment of the present disclosure.

[0065] FIG. 1B An example coherent receiver is illustrated in accordance with an embodiment of the present disclosure.

[0066] FIG. 2 A LIDAR system including a LIDAR pixel having a two-dimensional (2D) polarization beam splitting grating coupler as a receive optical antenna is illustrated in accordance with an embodiment of the present disclosure.

[0067] FIG. 3 A LIDAR system including a LIDAR pixel having a 2D polarization grating coupler as a transmit optical antenna is illustrated in accordance with an embodiment of the present disclosure.

[0068] FIG. 4A A block diagram of an example of a system environment for an autonomous vehicle is illustrated in accordance with an embodiment of the present disclosure.

[0069] FIG. 4BA block diagram illustrating an example of a system environment for an autonomous commercial truck vehicle, in accordance with an embodiment of the present disclosure.

[0070] FIG. 4C A block diagram illustrating an example of a system environment for an autonomous commercial truck vehicle, in accordance with an embodiment of the present disclosure.

[0071] FIG. 4D A block diagram illustrating an example of a system environment for an autonomous commercial truck vehicle, in accordance with an embodiment of the present disclosure. DETAILED DESCRIPTION

[0072] Embodiments of a LIDAR pixel with a dual polarization receiving optical antenna are described herein. The LIDAR pixel can include one or more modules, one or more integrated chips, or one or more circuits. Additionally, the LIDAR pixel can be implemented as a single packaged chip or implemented 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. One skilled in the relevant art will recognize, however, that the technology described herein can be practiced without one or more of the specific details, or with other methods, components, materials, etc. In other instances, well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring certain aspects.

[0073] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the application. Thus, the appearances of the phrase “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 can be combined in any suitable manner in one or more embodiments.

[0074] Throughout this specification, a number of terms are used. These terms, unless otherwise indicated, shall be accorded their ordinary meanings in the art. For the purposes of the present disclosure, the term “autonomous vehicle” includes vehicles with autonomous features at any level of autonomy with SAE International Standard J3016.

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

[0076] Frequency-modulated continuous wave (FMCW) LiDAR directly measures the range and velocity of an object or target by directing a frequency-modulated beam of light toward it. The light reflected from the object / target is combined with a tapped version of the beam. Once corrected for the Doppler shift required for a second measurement, the frequency of the resulting beat tone is proportional to the distance between the object and the LiDAR system. These two measurements, which can be performed simultaneously or separately, provide both range and velocity information.

[0077] Embodiments of this disclosure include a LIDAR device comprising LIDAR pixels 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 the returned beam. The first receiver generates a first signal in response to receiving a first polarization orientation of the returned 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 returned beam detected by the receiving optical antenna. Detecting two different polarization orientations of the returned beam can increase the signal-to-noise ratio (SNR) of the detected returned beam and thus increase the imaging quality of the LIDAR system. Additionally, detecting two different polarization orientations of the returned beam can allow the LIDAR system to detect additional information about the external environment, such as the polarization-dependent surface material of objects / targets in the external environment of the LIDAR system. FIGS. 1A-4D These and other implementation methods will be described in more detail.

[0078] FIG. 1A The illustration shows a LiDAR system 100 including LiDAR pixels 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 this. FIG. 1A The specific LIDAR pixel architecture shown is illustrated. LIDAR pixels can be implemented using any suitable chip design architecture. For example, the transmitting and receiving 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 transmitting 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. FIG. 1AIn particular embodiments, 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 receive optical antenna 110 is a dual-polarization receive 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 an external environment of the LIDAR system 100. The first polarization orientation can be orthogonal to the second polarization orientation. In FIG. 1A In particular embodiments, the receive 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 through a waveguide 112 to a first coherent receiver 121. The second single-polarization grating coupler 116 is configured to couple the second polarization orientation of the return beam through a waveguide 117 to a second coherent receiver 126.

[0080] In some embodiments, the first single-polarization grating coupler 111 is rotated relative to the second single-polarization grating coupler 116. In FIG. 1A In the particular 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 transmit optical antenna 105 is rotated relative to the first single-polarization grating coupler 111 and the second single-polarization grating coupler 116. In particular, in FIG. 1A In particular embodiments, the first single-polarization grating coupler 111 is rotated +45 degrees relative to the transmit optical antenna 105, and the second single-polarization grating coupler 116 is rotated -45 degrees relative to the transmit 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 can be an optical signal having the first polarization orientation. In FIG. 1A In particular embodiments, the first polarization orientation of the return beam is received by the first coherent receiver 121 through the waveguide 112 from the first single-polarization grating coupler 111, 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 processing logic 150 through a communication channel 122.

[0082] In some implementations, the second coherent receiver 126 is configured to generate the 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 the second polarization orientation. In FIG. 1A In some implementations, the second coherent receiver 126 receives the second polarization orientation of the return beam from the second single-polarization grating coupler 116 through the waveguide 117 and the second local oscillator signal 136 through the waveguide 137. The second signal 128 can be an electrical signal provided to the processing logic 150 through the communication channel 127.

[0083] The processing logic 150 is configured to generate the 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 can 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 can generate the image 155 in response to the first signal and the second signal received by the processing logic 150 through a plurality of LIDAR pixels 199 in the array of LIDAR pixels.

[0084] In operation, the transmit signal 101 can be emitted by the transmit optical antenna 105 as a transmit beam into free space. The transmit beam can propagate through one or more lenses and be deflected by the 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 the LIDAR pixels 199 as a return beam. The return beam can be reflected from the rotating mirror and propagate through one or more lenses, but is offset from the transmit optical antenna 105 due to the time difference in the rotation of the mirror. 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] FIG. 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 a return beam signal RB with a 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. The 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 to an output signal OUT. The output signal OUT can be an electrical signal. The output signal OUT can be a beat signal that represents a range and / or a velocity of one or more objects in an environment of the LIDAR system. For example, the communication channel 122 or 127 can be coupled to the output port 162.

[0086] FIG. 2 A LIDAR system 200 including a LIDAR pixel 299 is illustrated in accordance with an embodiment of the present disclosure. The LIDAR pixel 299 includes a transmit optical antenna 205, a receive optical antenna 210, a first coherent receiver 221, and a second coherent receiver 226. In FIG. 2 The receive optical antenna 210 of the LIDAR pixel 299 is shown as a two- dimensional (2D) polarization beam splitting grating coupler in the embodiment. The 2D polarization beam splitting grating coupler is configured to couple a first polarization of a return beam to the first coherent receiver 221 and a second polarization of the return beam to the second coherent receiver 226.

[0087] The transmit optical antenna 205 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 FIG. 2 The transmit optical antenna 205 is illustrated as a single polarization output coupler in the embodiment, and can emit 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 and a second polarization orientation of the returned beam. The returned beam is a reflection of the transmitted beam 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 beamsplitter coupler 210 is configured to couple the first polarization orientation of the returned beam to a first coherent receiver 221 via waveguide 212, and to couple the second polarization orientation of the returned beam to a second coherent receiver 226 via waveguide 217. In some embodiments, FIG. 1B The example coherent receiver 171 can be used as a first coherent receiver 221 and / or a 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 a first polarization orientation of the returned beam and a first local oscillator signal 231. The first local oscillator signal 231 may be an optical signal having the first polarization orientation. FIG. 2 In the process, the first coherent receiver 221 receives the first polarization orientation of the returned beam from the 2D polarization beamsplitter coupler 210 through waveguide 212, and the first coherent receiver 221 receives the first local oscillator signal 231 through waveguide 232. The first signal 223 may be an electrical signal provided to the processing logic 250 through 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 a second polarization orientation and a second local oscillator signal 236 of the returned beam. The second local oscillator signal 236 may be an optical signal having a second polarization orientation. FIG. 2 In this process, the second coherent receiver 226 receives the second polarization orientation of the returned beam from the 2D polarization beamsplitter coupler 210 via waveguide 217, and the second coherent receiver 226 also receives the second local oscillator signal 236 via waveguide 237. The second signal 228 may be an electrical signal provided to the processing logic 250 via communication channel 227.

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

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

[0093] FIG. 3 A LIDAR system 300 including a LIDAR pixel 399 is illustrated in accordance with an embodiment of the present disclosure. In FIG. 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 a transmit beam having orthogonal polarizations. In FIG. 3 In the illustrated embodiment, the transmit optical antenna 309 is configured to receive a first transmit signal TX1 301 through the waveguide 302 and a second transmit signal TX2 302 through 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 facilitate providing additional information about the polarization-dependent reflectivity of the environment.

[0094] The receive 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 configured similarly to the 2D polarization beam-splitting grating coupler 210 of FIG. 2 The 2D polarization beam-splitting grating coupler 310 is thus configured to couple a first polarization of a return beam to the first coherent receiver 321 and a second polarization of the return beam to the second coherent receiver 326. As FIG. 3As illustrated in FIG. 3, the first polarization orientation can be orthogonal to the second polarization orientation. The transmitted beam emitted by the 2D polarization beam splitter grating coupler 310 can include the first polarization orientation and the second polarization orientation. The transmitted beam can be an infrared transmitted beam. The transmitted beam can be a near-infrared transmitted beam. The transmit signal TX1301 and / or the transmit signal TX2302 can be generated by a laser, and the transmitted beam emitted by the transmit optical antenna 309 can have a very narrow linewidth.

[0095] In some implementations, the receive optical antenna 310 is a dual-polarization receive 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 transmitted beam reflected from a target in an external environment of the LIDAR system 300. The first polarization orientation can be orthogonal to the second polarization orientation. The 2D polarization beam splitter 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 to couple the second polarization orientation of the return beam to the second coherent receiver 326 through the waveguide 317. In some implementations, FIG. 1A The example coherent receiver 171 of FIG. 1 can be used as the first coherent receiver 321 and / or the second coherent receiver 326.

[0096] In some implementations, 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 the first polarization orientation. In FIG. 3 In the example of FIG. 3, the first polarization orientation of the return beam is received by the first coherent receiver 321 from the 2D polarization beam splitter 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 implementations, 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 a second local oscillator signal 336. The second local oscillator signal 336 can be an optical signal having the second polarization orientation. In FIG. 3 In the example of FIG. 3, the second polarization orientation of the return beam is received by the second coherent receiver 326 from the 2D polarization beam splitter grating coupler 310 through the waveguide 317, and the second local oscillator signal 336 is received by the second coherent receiver 326 through the waveguide 337. The second signal 328 can be an electrical signal provided to the processing logic 350 through 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 can include an array of LIDAR pixels 399 configured to provide the first signal (e.g., signal 323) and the second signal (e.g., signal 328) to the processing logic 350. In this context, the processing logic 350 can generate the image 355 in response to the first signal and the second signal received by the processing logic 350 through a plurality of the LIDAR pixels 399 in the array of LIDAR pixels.

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

[0100] 1. System Environment for Autonomous Vehicles

[0101] FIG. 4A is a block diagram illustrating an example of a system environment for an autonomous vehicle, in accordance with some embodiments.

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

[0103] For simplicity, the embodiments discussed below will focus on wheeled land vehicles, such as cars, vans, trucks, buses, etc. In such embodiments, the prime mover 494 can include one or more electric motors and / or internal combustion engines (etc.). The energy source can 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. The drivetrain 498 can include wheels and / or tires and a transmission and / or any other mechanical drive components to convert the output of the prime mover 494 into vehicle motion, one or more brakes configured to controllably stop or slow the vehicle 410A, and a direction or steering assembly suitable for controlling the trajectory of the vehicle 410A (e.g., a rack and pinion steering linkage enabling one or more wheels of the vehicle 410A to pivot about a generally vertical axis to change the angle of the plane of rotation of the wheel relative to the longitudinal axis of the vehicle). In some embodiments, a combination of powertrain and energy source can be used (e.g., in the case of an electric / oil hybrid vehicle), and in some instances, multiple electric motors can be used (e.g., dedicated to individual wheels or axles) as the prime mover.

[0104] The direction control 482 can include one or more actuators and / or sensors for controlling and receiving feedback from the direction or steering assembly to enable the vehicle 410A to follow a desired trajectory. The powertrain control 484 can be configured to control the output of the powertrain 402, e.g., to control the output power of the prime mover 494, to control the gear of a transmission in the drivetrain 498, etc., thereby controlling the speed and / or direction of the vehicle 410A. The brake control 416 can be configured to control one or more brakes, e.g., disc or drum brakes coupled to the wheels of the vehicle, to slow or stop the vehicle 410A.

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

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

[0107] The sensors 430 can include various sensors suitable for collecting information from the vehicle's surroundings for use in controlling the operation of the vehicle. For example, the sensors 430 can include radar sensors 434, lidar (light detection and ranging) sensors 436, 3D positioning sensors 438, such as any of an accelerometer, a gyroscope, a magnetometer, or a satellite navigation system such as a GPS (Global Positioning System), GLONASS (Globalnaya Navigazionnaya Sputnikovaya Sistema or Global Navigation Satellite System), BeiDou Navigation Satellite System (BDS), Galileo, compass, etc. The 3D positioning sensors 438 can be used to determine the vehicle's position on the earth using satellite signals. The sensors 430 can include a camera 440 and / or an IMU (inertial measurement unit) 442. The camera 440 can be a single or stereo camera and can record still and / or video images. The IMU 442 can include multiple gyroscopes and accelerometers that are capable of detecting linear and rotational movement 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 of the sensors 430 can output sensor data at various data rates, which can be different from the data rates of the other sensors 430.

[0108] The outputs of the sensors 430 can be provided to a set of control subsystems 450, including a localization subsystem 452, a planning subsystem 456, a perception subsystem 454, and a control subsystem 458. The localization subsystem 452 can perform functions such as precisely determining the position and orientation (sometimes also referred to as "pose") of the vehicle 410A within its surroundings, and generally within some frame of reference. As part of generating labeled autonomous vehicle data, the position of the autonomous vehicle can be compared to the positions of additional vehicles in the same environment. The perception subsystem 454 can perform functions such as detecting, tracking, determining, and / or identifying objects within the vehicle 410A's surroundings. Machine learning models can be used in tracking objects. The planning subsystem 456 can perform functions such as planning a trajectory for the vehicle 410A over some time horizon given a desired destination, as well as static and moving objects within the environment. Machine learning can be used in planning vehicle trajectories. The control subsystem 458 can perform functions such as generating appropriate control signals to control the various controls in the vehicle control system 420 in order to implement the planned trajectory of the vehicle 410A. Machine learning models can be utilized to generate one or more signals to control the autonomous vehicle to implement the planned trajectory.

[0109] It will be appreciated that, FIG. 4AThe assembly of components of the vehicle control system 420 illustrated in the figure is merely exemplary. In some embodiments, individual sensors may be omitted. Additionally or alternatively, in some embodiments, FIG. 4A The multiple sensor types illustrated in the diagram can be used for redundancy and / or coverage of different areas around the vehicle, and other types of sensors can be used. Similarly, in other embodiments, different types and / or combinations of control subsystems can be used. Furthermore, although subsystems 452 to 458 are illustrated separately from processor 422 and memory 424, it will be understood that in some embodiments, some or all of the functionality of subsystems 452 to 458 can be implemented using program code instructions 426 residing in one or more memories 424 and executed by one or more processors 422, and these subsystems 452 to 458 may be implemented using the same processor and / or memory in some instances. Subsystems can be implemented, at least in part, using various special-purpose circuit logics, various processors, various field-programmable gate arrays (“FPGAs”), various application-specific integrated circuits (“ASICs”), various real-time controllers, etc., and as described above, multiple subsystems can utilize circuit systems, processors, sensors, and / or other components. Furthermore, the various components in the vehicle control system 420 can be networked in various ways.

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

[0111] Typically, countless different architectures can be used to implement this. FIG. 4A The various components illustrated in the diagram represent various combinations of software, hardware, circuit logic, sensors, networks, etc. For example, each processor can be implemented as a microprocessor, and each memory can represent a random access memory (“RAM”) device, including main memory and 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 can be considered to include memory storage devices physically located elsewhere in the vehicle 410A, such as any cache memory in the processor, and any storage capacity used as virtual memory, such as stored in a mass storage device or on another computer controller. FIG. 4AOne or more of the processors illustrated in the vehicle 410A or entirely separate processors can be used to implement additional functionality in the vehicle 410A beyond the purposes of autonomous control, such as controlling entertainment systems, operating doors, lights, convenience features, etc.

[0112] Additionally, for additional storage, the vehicle 410A can include one or more mass storage devices, such as removable disk drives, hard disk drives, direct access storage devices (“DASD”), optical disk drives (e.g., CD drives, DVD drives, etc.), solid-state storage drives (“SSD”), network attached storage, storage area networks, and / or tape drives, etc.

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

[0114] Further, the vehicle 410A can include one or more network interfaces, such as network interface 462, that are suitable for communicating with one or more networks 470 (e.g., local area networks (“LANs”), wide area networks (“WANs”), wireless networks, and / or the Internet, etc.) to allow for 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 can be uploaded to a computing system 472 via the network 470 for additional processing. A timestamp can be added to each instance of vehicle data prior to upload. With reference to FIG. 2 Additional processing of autonomous vehicle data by the computing system 472 is described in accordance with many implementations.

[0115] FIG. 4A Each of the processors illustrated in the vehicle 410A, as well as various additional controllers and subsystems disclosed herein, generally operate under the control of an operating system and execute or otherwise rely upon various computer software applications, components, programs, objects, modules, data structures, etc., as will be more fully described below. Further, various applications, components, programs, objects, modules, etc. can also be executed on one or more processors in another computer of the vehicle 410A, coupled to the vehicle 410A via the network 470, for example, in a distributed, cloud-based or client-server computing environment, wherein processing required to implement the functionality of the computer programs can be allocated to multiple computers and / or services on the network.

[0116] Generally, the routines executed to implement the various implementations described herein, whether implemented as part of an operating system or a specific application, component, program, object, module, or sequence of instructions, or even a subset thereof, will be referred to herein as "program code," or simply "code." Program code can include one or more instructions that are resident at various times in various memory and storage devices, and that, when read and executed by one or more processors, perform the steps or elements of the steps described herein that are required to execute embodiments of the disclosure. Moreover, while embodiments have and will be described, and claims will be made, using terminology commonly employed by those skilled in the art, the instant disclosure is not intended to be limited to the specific implementations disclosed. On the contrary, it is intended to cover all modifications, enhancements, alternatives, equivalents, and the like, falling within the scope of the instant disclosure.

[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 disks, magnetic tape, and optical disks (e.g., CD-ROMs, DVDs, etc.), among others.

[0118] Additionally, various program code described hereinafter can be identified based upon the application within which it is implemented in a specific embodiment. However, it should be appreciated that any particular program nomenclature that follows is used only for convenience, and thus is not intended to limit the application to a particular application. Additionally, given the typically endless number of combinations and permutations of program code possibilities, the application should not be limited to those combinations and permutations described hereinafter and / or presented with respect to one particular application but could encompass any and all novel combinations and permutations underlying this present disclosure.

[0119] FIG. 4A The environment illustrated in FIG. 1 is not intended to limit the embodiments disclosed herein. Indeed, 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] The truck can include a lidar system (e.g., FIG. 4Alidar system 400 can be used in a vehicle control system 420). In some embodiments, a lidar system can use frequency modulation to encode optical signals and use optics to scatter the encoded optical signals into free space. For example, by detecting the frequency difference between the encoded optical signals and return signals reflected back from objects, a frequency-modulated (FM) lidar system can determine the location of objects and / or use the Doppler effect to precisely measure the velocity of objects. FM lidar systems can use continuous wave (referred to as "FMCW lidar" or "coherent FMCW lidar") or quasi-continuous wave (referred to as "FMQW lidar"). In some embodiments, a lidar system can use phase modulation (PM) to encode optical signals and use optics to scatter the encoded optical signals into free space.

[0122] For automotive and / or commercial truck applications, FM or PM lidar systems can provide significant advantages over traditional lidar systems. First, in some instances, an object (e.g., a pedestrian wearing dark clothing) can have a low reflectivity because it reflects only a small amount (e.g., 10% or less) of the light hitting the object back to the sensor (e.g., FIG. 4A of the sensor 430). In other instances, an object (e.g., a shiny road sign) can have a high reflectivity (e.g., more than 10%) because it reflects a large amount of the light hitting the object back to the sensor of the FM lidar system.

[0123] Regardless of the reflectivity of the object, FM lidar systems are able to detect (e.g., classify, discriminate, discover, etc.) objects at greater distances (e.g., 2x) than traditional lidar systems. For example, FM lidar systems can detect low reflectivity objects 300 meters away, and high reflectivity objects 400 meters away.

[0124] To achieve this improvement in detection capability, FM lidar systems can use sensors (e.g., FIG. 4A(Sensor 430 in the example). In some implementations, these sensors may 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 FM or PM lidar systems within the infrared wavelength range, FM or PM lidar systems can broadcast stronger light pulses or beams while meeting eye safety standards. Conventional lidar systems are typically not single-photon sensitive and / or operate only within the near-infrared wavelength range, thus requiring them to limit their light output (and distance detection capability) 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 driven at highway speeds.

[0126] Another advantage of FM lidar systems is their ability to provide accurate velocity for each data point instantaneously. In some implementations, 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 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 encountered on roads less than 100 meters per second (m / s), this shift at a wavelength of 1550 nanometers (nm) totals 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 much faster.

[0127] Instantaneous velocity calculations also make 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, FM lidar sensors (e.g., FIG. 4A The sensor 430 in the system may receive only a few returns from an object 300 meters away (e.g., hit), but if these returns give a speed value of interest (e.g., moving toward the vehicle at a speed >70 mph), the FM lidar system and / or autonomous vehicle control system can determine the appropriate weights of the probabilities associated with the object.

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

[0129] Another advantage of FM lidar systems is that they have less static compared to traditional lidar systems. That is, traditional lidar systems that are designed to be sensitive to light often perform poorly in bright sunlight. These systems are also susceptible to cross-talk (e.g., when a sensor is confused by the light pulses or beams of each other) and self-interference (e.g., when a sensor is confused by its own previous light pulses or beams). To overcome these shortcomings, vehicles that use traditional lidar systems often require additional hardware, complex software, and / or more computing power to manage this “noise.”

[0130] By contrast, FM lidar systems are not susceptible to these types of problems because each sensor is specifically designed to only respond to its own light characteristics (e.g., beam, wave, pulse). If the returning light does not match the timing, frequency, and / or wavelength of the originally emitted light, then the FM sensor can filter (e.g., remove, ignore, etc.) that data point. Thus, FM lidar systems produce (e.g., generate, derive, etc.) more accurate data with fewer hardware or software requirements, resulting in safer and smoother driving.

[0131] Finally, FM lidar systems are more easily scalable than traditional lidar systems. As more and more self-driving vehicles (e.g., cars, commercial trucks, etc.) appear on the road, vehicles powered by FM lidar systems can not have to deal with the interference problems caused by sensor cross-talk. Moreover, FM lidar systems use less peak power of light than traditional lidar sensors. Thus, some or all of the optical components of FM lidar can be produced on a single chip, which creates its own benefits as discussed herein.

[0132] 3. Commercial Truck

[0133] FIG. 4BThis is 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 cargo 406B. In some embodiments, the 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 a variety of transport modes to move cargo), and / or any other road-based freight transport application. The commercial truck 402B may be a flatbed truck, a refrigerated truck (e.g., a frozen truck), a ventilated van (e.g., a dry van), a mobile truck, etc. Cargo 406B may be goods and / or products. The commercial truck 402B may include trailers for carrying cargo 406B, such as flatbed trailers, low-floor trailers, ladder trailers, retractable flatbed trailers, side trailers, etc.

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

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

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

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

[0138] Environment 400C includes object 410C (inFIG. 4C An object 410C (shown in

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

[0140] The environment 400D includes an object 410D (shown in FIG. 4D An object 410D (shown in

[0141] In commercial truck applications, it is important to effectively detect objects at all ranges due to the increased weight and correspondingly longer stopping distance required for such vehicles. FM lidar systems (e.g., FMCW and / or FMQW systems) or PM lidar systems are well suited for commercial truck applications due to the advantages described above. Thus, a commercial truck equipped with such a system can have enhanced capabilities 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 an FM or PM lidar system can be used in semi-autonomous applications, where 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, where the commercial truck is operated entirely by the FM or lidar system, alone or in conjunction with other vehicle systems.

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

[0143] In lidar systems that use CW modulation, the modulator continuously modulates the laser. For example, if the modulation period is 10 seconds, then the input signal is modulated for the entire 10 seconds. In contrast, in lidar systems that use quasi-CW modulation, the modulator modulates the laser to have both active and inactive portions. For example, for a 10 second period, the modulator modulates the laser for only 8 seconds (sometimes referred to as the “active portion”), but not for 2 seconds (sometimes referred to as the “inactive portion”). By doing so, the lidar system is able to reduce power consumption for that 2 seconds, as the modulator does not have to provide a continuous signal.

[0144] In frequency modulated continuous wave (FMCW) lidar 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 always on (e.g., enabled, powered on, transmitted, etc.). In some implementations, the quasi-CW modulation can have a duty cycle equal to or greater than 1% and up to 50%. If energy in the off state (e.g., disabled, powered off, etc.) can be consumed during the actual measurement time, then there can be an improvement in signal-to-noise ratio (SNR) and / or a reduction in signal processing requirements to coherently integrate all the energy over a longer time scale.

[0145] The term “processing logic” in this disclosure can 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 to perform the operations and / or to store data. The processing logic can also include analog or digital circuitry to perform operations in accordance with embodiments of the disclosure.

[0146] “Memory” or “memories” described in this disclosure can include one or more volatile or non-volatile memory architectures. The “memory” or “memories” can 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 can include RAM, ROM, EEPROM, flash memory, CD-ROM, digital versatile disks (DVD), high definition multimedia / data storage disks or other optical storage, magnetic cassettes, magnetic tapes, 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] A network can include any network or network system such as, but not limited to, the following: 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 combination wireless and wired network; and a satellite network.

[0148] A communication channel can include one or more wired or wireless communications or be routed through one or more wired or wireless communications that utilize IEEE 802.11 protocol, Bluetooth, SPI (serial peripheral interface), I 2 A communication channel can include one or more wired or wireless communications or be routed through one or more wired or wireless communications that utilize IEEE 802.11 protocol, Bluetooth, SPI (serial peripheral interface), I

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

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

[0151] A tangible non-transitory machine-readable storage medium includes any mechanism that provides (i.e., stores) information in a form accessible by a machine (e.g., a computer, network device, personal digital assistant, manufacturing tool, any device with a set of one or more processors, etc.). For example, a machine-readable storage medium includes 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.).

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

[0153] These modifications can be made in light of the above detailed description. The terms used in the following claims should not be construed to limit the application to the specific embodiments disclosed in the specification and the drawings. Rather, the scope of the application is to be determined entirely by the following claims, which are to be construed in accordance with the 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 receive 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 -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 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 of claim 1, wherein, the first single polarization grating coupler is offset from the second single polarization grating coupler.

3. The LIDAR system of claim 1, wherein, the first single polarization grating coupler is rotated relative to the second single polarization grating coupler.

4. The LIDAR system of claim 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 of claim 3, wherein, a 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 of claim 1, 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 of claim 1, wherein, the first local oscillator signal and the second local oscillator signal have a same wavelength as the return beam.

8. The LIDAR system of claim 1, wherein, the transmit beam has the first polarization orientation.

9. The LIDAR system of claim 1, wherein, the transmit beam is infrared, and wherein the return beam is infrared.

10. The LIDAR system of claim 9, wherein, the transmit beam and the return beam are narrowband near-infrared wavelengths.

11. The LIDAR system of claim 1, wherein, the first polarization orientation is orthogonal to the second polarization orientation.

12. The LIDAR system of claim 1, wherein, the return beam is the transmit beam reflected from a target.

13. An autonomous vehicle control system for an autonomous vehicle, the autonomous vehicle control system comprising: a light detection and ranging (LIDAR) device 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 receive 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 -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 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 returned beam; A first receiver, configured to generate a first signal in response to receiving a first polarization orientation and a first local oscillator signal from the returning beam of the receiving optical antenna; and A second receiver, configured to generate a second signal in response to receiving a second polarization orientation and a second local oscillator signal from the returning beam of the receiving optical antenna; and One or more processors configured to control the autonomous vehicle in response to a first electrical signal and a second electrical signal.

14. The autonomous vehicle control system according to claim 13, wherein, The first single-polarization grating coupler is configured to couple the first polarization orientation of the returned beam to the first receiver; and The second single-polarization grating coupler is configured to couple the second polarization orientation of the returned beam to the second receiver.

15. The autonomous vehicle control system of claim 14, wherein, The first single-polarization grating coupler rotates relative to the second single-polarization grating coupler.

16. The autonomous vehicle control system of claim 13, wherein, The transmitting optical antenna includes a two-dimensional (2D) polarization grating coupler, and the transmitting beam includes a first polarization orientation and a second polarization orientation.

17. The autonomous vehicle control system of claim 13, wherein, The transmitted beam and the returned beam are narrowband near-infrared wavelengths.

18. An autonomous vehicle, comprising: Light detection and ranging (LIDAR) sensors, including: A transmitting optical antenna configured to emit a transmitting beam; A receiving optical antenna, the receiving optical antenna comprising: 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 the returning beam, and 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 returned beam; A first receiver, configured to generate a first signal in response to receiving a first polarization orientation and a first local oscillator signal from the returning beam of the receiving optical antenna; and A second receiver, configured to generate a second signal in response to receiving a second polarization orientation and a second local oscillator signal from the returning beam of the receiving optical antenna; and One or more processors configured to control the autonomous vehicle in response to a first electrical signal and a second electrical signal.

19. The autonomous vehicle of claim 18, wherein, The transmitted beam and the returned beam are narrowband near-infrared wavelengths.

20. The autonomous vehicle of claim 18, wherein, The transmitting optical antenna includes a two-dimensional (2D) polarization grating coupler, and the transmitting beam includes a first polarization orientation and a second polarization orientation.

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