LIDAR Sensor System Including Dual-Polarization Transmitting and Receiving Optical Antenna

Abstract

The LIDAR sensor system includes a dual-polarization optical antenna, a single-polarization optical antenna, a first receiver, and a second receiver. The dual-polarization optical antenna is configured to (i) emit a transmission beam having a first polarization direction and (ii) detect a return beam having a second polarization direction. The single-polarization optical antenna is configured to detect a return beam having the second polarization direction.

Description

Technical Field

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

Background Art

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

Summary of the Invention

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

[0004] In one embodiment, the dual-polarization optical antenna includes a two-dimensional (2D) polarization splitting grating coupler that includes a first port and a second port. The 2D polarization splitting grating can be configured to receive a transmission signal at the first port and can be configured to provide a return beam having a second polarization to the second port coupled to a second receiver.

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

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

[0007] In one embodiment, the dual-polarization optical antenna is offset from the single-polarization optical antenna by a specific distance.

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

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

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

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

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

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

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

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

[0016] Embodiments of the present disclosure include an autonomous vehicle control system for an autonomous vehicle. The autonomous vehicle control system may include a light detection and ranging (LIDAR) device and one or more processors. The LIDAR device may include one or more LIDAR pixels. At least one of the one or more LIDAR pixels may include a dual-polarization optical antenna, a first receiver, and a second receiver. The dual-polarization optical antenna may be configured to (i) emit a transmitted beam having a first polarization direction and (ii) detect a return beam having a second polarization direction. The first receiver may be configured to generate a first electrical signal in response to receiving the second polarization direction of the return beam and in response to a first local oscillator signal. The second receiver may be configured to generate a second electrical signal in response to receiving the second polarization direction of the return beam from the dual-polarization optical antenna and in response to a second local oscillator signal. The one or more processors may be configured to control the autonomous vehicle in response to the first electrical signal and the second electrical signal.

[0017] In one embodiment, the dual-polarization optical antenna includes a two-dimensional (2D) polarization splitting grating coupler having a first port and a second port. The 2D polarization splitting grating can be configured to receive a transmission signal at the first port and can be configured to provide a return beam having a second polarization to the second port coupled to a second receiver.

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

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

[0020] In one embodiment, the dual-polarization optical antenna is offset from the single-polarization optical antenna by a specific distance.

[0021] In one embodiment, the autonomous vehicle control system further includes a rotating mirror and a birefringent slab. The rotating mirror can be configured to direct a transmission beam into the LIDAR environment and can be configured to direct a return beam to at least one of the one or more LIDAR pixels. The birefringent slab can be disposed between the rotating mirror and at least one of the one or more LIDAR pixels. The birefringent slab can be configured to direct a return beam having a second polarization direction to the single-polarization optical antenna or the dual-polarization optical antenna.

[0022] Embodiments of the present disclosure include autonomous vehicles. The autonomous vehicle may include a Light Detection and Ranging (LIDAR) device and one or more processors. The LIDAR device may include one or more LIDAR pixels. At least one of the one or more LIDAR pixels may include a dual-polarization optical antenna, a first receiver, and a second receiver. The dual-polarization optical antenna may be configured to (i) emit a transmission beam having a first polarization direction and (ii) detect a return beam having a second polarization direction. The first receiver may be configured to generate a first electrical signal in response to receiving the second polarization direction of the return beam and in response to a first local oscillator signal. The second receiver may be configured to generate a second electrical signal in response to receiving the second polarization direction of the return beam from the dual-polarization optical antenna and in response to a second local oscillator signal. The one or more processors may be configured to control the autonomous vehicle in response to the first signal and the second signal.

[0023] Embodiments of the present disclosure include a Light Detection and Ranging (LIDAR) sensor system including one or more LIDAR pixels. At least one of the one or more LIDAR pixels may include a dual-polarization optical antenna, a first receiver, and a second receiver. The dual-polarization optical antenna may be configured to (i) emit a transmission beam having a first polarization direction and (ii) detect a return beam having a second polarization direction. The first receiver may be configured to generate a first signal in response to receiving the second polarization direction of the return beam and in response to a first local oscillator signal. The second receiver may be configured to generate a second signal in response to receiving the second polarization direction of the return beam from the dual-polarization optical antenna and in response to a second local oscillator signal.

[0024] In one embodiment, the dual-polarization optical antenna includes a two-dimensional (2D) polarization splitting grating coupler including a first port and a second port. The 2D polarization splitting grating may be configured to receive a transmission signal at the first port and may be configured to provide a return beam having a second polarization to the second port coupled to the second receiver.

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

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

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

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

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

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

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

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

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

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

[0035] In one embodiment, the return beam is a transmission beam reflected from an object.

[0036] Embodiments of the present disclosure include an autonomous vehicle control system for an autonomous vehicle. The autonomous vehicle control system may include a light detection and ranging (LIDAR) device and one or more processors. The LIDAR device may include one or more LIDAR pixels. At least one of the one or more LIDAR pixels may include a dual-polarization optical antenna, a first receiver, and a second receiver. The dual-polarization optical antenna may be configured to (i) emit a transmission beam having a first polarization direction and (ii) detect a return beam having a second polarization direction. The first receiver may be configured to generate a first electrical signal in response to receiving the second polarization direction of the return beam and in response to a first local oscillator signal. The second receiver may be configured to generate a second electrical signal in response to receiving the second polarization direction of the return beam from the dual-polarization optical antenna and in response to a second local oscillator signal. The one or more processors may be configured to control the autonomous vehicle in response to the first electrical signal and the second electrical signal.

[0037] In one embodiment, the dual-polarization optical antenna includes a two-dimensional (2D) polarization splitting grating coupler having a first port and a second port. The 2D polarization splitting grating can be configured to receive a transmission signal at the first port and can be configured to provide a return beam having a second polarization to the second port coupled to a second receiver.

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

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

[0040] In one embodiment, the dual-polarization optical antenna is offset from the single-polarization optical antenna by a specific distance.

[0041] In one embodiment, the autonomous vehicle control system further includes a rotating mirror and a birefringent slab. The rotating mirror can be configured to direct a transmission beam into a LIDAR environment and can be configured to direct a return beam to at least one of the one or more LIDAR pixels. The birefringent slab can be disposed between the rotating mirror and at least one of the one or more LIDAR pixels. The birefringent slab can be configured to direct a return beam having a second polarization direction to the single-polarization optical antenna or the dual-polarization optical antenna.

[0042] Embodiments of the present disclosure include autonomous vehicles. The autonomous vehicle may include a Light Detection and Ranging (LIDAR) device and one or more processors. The LIDAR device may include one or more LIDAR pixels. At least one of the one or more LIDAR pixels may include a dual-polarization optical antenna, a first receiver, and a second receiver. The dual-polarization optical antenna may be configured to (i) emit a transmit beam having a first polarization direction and (ii) detect a return beam having a second polarization direction. The first receiver may be configured to generate a first electrical signal in response to receiving the return beam in the second polarization direction and in response to a first local oscillator signal. The second receiver may be configured to generate a second electrical signal in response to receiving the return beam in the second polarization direction from the dual-polarization optical antenna and in response to a second local oscillator signal. The one or more processors may be configured to control the autonomous vehicle in response to the first signal and the second signal.

Brief Description of the Drawings

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

[0044]

Figure 1

[0045]

Figure 2a

Figure 2b

[0046]

Figure 3

[0047]

Figure 4a

[0048]

Figure 4b

[0049]

Figure 4c

[0050]

Figure 4d

DETAILED DESCRIPTION OF THE INVENTION

[0051] Embodiments of a LIDAR pixel with a dual-polarization transceiver optical antenna will be described. The LIDAR pixel may include one or more modules, one or more integrated chips, or one or more electrical circuits. Also, the LIDAR pixel may be implemented as a single-package chip, or may be implemented as a modular design such that the LIDAR pixel includes multiple package chips. In the following description, numerous specific details are presented in order to provide a complete understanding of the implementation. However, those skilled in the relevant art will recognize that the techniques described herein can be practiced without one or more of the specific details or using other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects.

[0052] 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 invention. Thus, appearances 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. Also, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0053] Throughout this specification, several technical terms are used. These terms have their ordinary meanings in the technical field from which they are derived, unless specifically defined herein or the context of use clearly indicates otherwise. For the purposes of this disclosure, the term "Autonomous Vehicle" includes vehicles equipped with autonomous functions having any level of autonomy of SAE International Standard J3046.

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

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

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

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

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

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

[0060] In some embodiments, the first coherent receiver 121 can be configured to generate a first signal 123 in response to the second polarization direction of the return beam and the first local oscillator signal LO1131. The first local oscillator signal 131 can be an optical signal having the second polarization direction. In FIG. 1, according to an embodiment, the second polarization direction of the return beam is received by the first coherent receiver 121 from the received optical antenna 106 via the waveguide 112, and the first local oscillator signal 131 is received by the first coherent receiver 121 via the waveguide 132. The first signal 123 can be an electrical signal provided to the processing logic 150 via the communication channel 122.

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

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

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

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

[0065] FIG. 2a shows a coherent receiver 200. The coherent receiver 200 may include an optical mixer 202, a return beam port 204, a local oscillator port 208, and an output port 212. According to an embodiment, the optical mixer 202 may combine a return beam signal RB with a local oscillator signal LO to generate an output signal OUT. The optical mixer 202 may be configured to receive two or more optical signals. The optical mixer 202 may be coupled to receive the return beam signal RB from the return beam port 204 via a waveguide 206. According to an embodiment, the optical mixer 202 may be coupled to receive the local oscillator signal LO from the local oscillator port 208 via a waveguide 210. The optical mixer 202 may combine input signals to generate a plurality of combined output signals OUT1 and OUT2. The number of output signals from the optical mixer is not limited to a specific number and may be any suitable number. According to an embodiment, 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 into the output signal OUT. The output signal OUT may be an electrical signal. The output signal OUT may be a beat signal representing the distance and / or speed of one or more objects in the environment of the LIDAR system. Each change in these output signals OUT may provide object characteristics (e.g., distance, reflectivity) regarding the objects in the environment where the return beam is reflected. The object characteristics (e.g., distance, reflectivity) may enable, for example, an autonomous vehicle (e.g., a truck) to perform vehicle operations (e.g., stop, turn direction, ignore) based on the characteristics of the object. Each output signal may be provided to a respective one of a plurality of receivers so that a plurality of output signals can be received and processed simultaneously.

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

[0067] FIG. 3 shows an illustration of a LIDAR system 300 showing a method by which LIDAR pixels 102 can be used to correct beam walk-off and support beam scanning, according to an embodiment of the present disclosure.

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

[0069] During the transmission time when the transmission beam 302 and the return beam 314 move to the object 312 and back to the mirror 310 again, the mirror 310 can rotate slightly. The amount of rotation can vary depending on the distance that the transmission beam 302 and the return beam 314 have traveled. Due to the rotation of the mirror 310, the return beam 314 can enter the lens 308 at an angle different from that of the transmission beam 302. When the position of the return beam 314 on the mirror 310 changes, the return beam 314 may be walked off or may escape from the optical antenna 104. However, since the LIDAR pixel 102 includes the receiving optical antenna 106, when the return beam 314 returns at an offset away from the optical antenna 104 and enters the receiving optical antenna 106, the LIDAR pixel 102 can receive the return beam 314 in the second polarization direction.

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

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

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

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

[0074] 1. System Environment for Autonomous Vehicles FIG. 4a is a block diagram illustrating an example of a system environment for an autonomous vehicle according to some embodiments.

[0075] Referring to FIG. 4a, an exemplary autonomous vehicle 410A is shown in which various techniques disclosed herein can be implemented. For example, vehicle 410A can include a power train 492 that includes a prime mover 494 driven by an energy source 496 and capable of powering a drive train 498, and a control system 480 that includes a direction control 482, a power train control 484, and a brake control 486. Vehicle 410A can be any of a variety of types of vehicles capable of transporting people and / or cargo and operating in a variety of environments, and it will be understood that the foregoing components 480-498 can vary widely depending on the type of vehicle in which these components are used.

[0076] For simplicity, the embodiments discussed below focus on wheeled land vehicles such as automobiles, vans, trucks, buses, etc. In these embodiments, the prime mover 494 may include, among other things, one or more electric motors and / or internal combustion engines. The energy source may include, for example, a fuel system (e.g., providing gasoline, diesel, hydrogen, etc.), a battery system, a solar panel or other renewable energy source, and / or a fuel cell system. The drive train 498 includes a transmission for converting the output of the prime mover 494 into vehicle operation and / or any other mechanical drive components, along with wheels and / or tires, one or more brakes configured to controllably stop or decelerate the vehicle 410A, and a direction or steering component (e.g., a rack and pinion steering linkage for generally pivoting one or more wheels of the vehicle 410A about a vertical axis to vary the angle of the rotational plane of the wheels relative to the longitudinal axis of the vehicle) suitable for controlling the trajectory of the vehicle 410A. In some embodiments, a combination of a power train and an energy source can be used (e.g., in the case of an electric / gas hybrid vehicle), and in some examples, multiple electric motors (e.g., dedicated to individual wheels or axles) can be used as the prime mover.

[0077] The direction control 482 may include one or more actuators and / or sensors for controlling and receiving feedback from the direction or steering component so that the vehicle 410A follows a desired trajectory. The power train control 484 may be configured to control the output of the power train 492, e.g., to control the output of the prime mover 494, to control the gears of the transmission within the drive train 498, thereby enabling control of the speed and / or direction of the vehicle 410A. The brake control 486 may be configured to control one or more brakes for decelerating or stopping the vehicle 410A, e.g., disk or drum brakes coupled to the wheels of the vehicle.

[0078] Other vehicle types, including but not limited to off-road vehicles, all-terrain vehicles, or track-type vehicles, construction equipment, etc., can necessarily use different power trains, drive trains, energy sources, direction controls, power train controls, and brake controls. Further, in some embodiments, some components may be combined, for example, when the direction control of the vehicle is primarily handled by changing the output of one or more prime movers. Accordingly, the embodiments disclosed herein are not limited to specific applications in an autonomous wheeled land vehicle of the technology disclosed herein.

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

[0080] Sensor 430 may include various sensors suitable for collecting information from the vehicle's surrounding environment for use in controlling the operation of the vehicle. For example, sensor 430 may include a radar sensor 434, a LIDAR (Light Detection and Ranging) sensor 436, a 3D positioning sensor 438, such as an accelerometer, a gyroscope, a magnetometer, or any of the satellite navigation systems such as GPS (Global Positioning System), GLONASS (Globalnaya Navigazionnaya Sputnikovaya Sistema, or Global Navigation Satellite System), BeiDou Navigation Satellite System (BDS), Galileo, Compass, etc. The 3D positioning sensor 438 can be used to determine the position of the vehicle on the earth using satellite signals. Sensor 430 may include a camera 440 and / or an Inertial Measurement Unit (IMU) 442. The camera 440 can be a monographic or stereographic camera and can record still images and / or videos. The IMU 442 may include a plurality of gyroscopes and accelerometers that can detect the linear and rotational movements of the vehicle in three directions. One or more encoders (not shown), such as wheel encoders, can be used to monitor the rotation of one or more wheels of the vehicle 410A. Each sensor 430 can output sensor data at various data rates, which may be different from the data rates of other sensors 430.

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

[0082] The collection of components shown in FIG. 4a for vehicle control system 420 will be understood to be merely exemplary. In some embodiments, individual sensors can be omitted. Additionally or alternatively, in some embodiments, multiple sensors of the type shown in FIG. 4a can be used to cover redundancy and / or various regions around the vehicle, and other types of sensors can be used. Similarly, various types and / or combinations of control subsystems can be used in other embodiments. Also, although subsystems 452-458 are shown as being separate from processor 422 and memory 424, in some embodiments, some or all of subsystems 452-458 can reside in one or more memories 424 and be implemented with program code instructions 426 performed by one or more processors 422, and it will be understood that these subsystems 452-458 can, in some cases, be implemented using the same processor and / or memory. Subsystems can be implemented using at least in part various dedicated 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, many subsystems can use circuits, processors, sensors, and / or other components. Also, the various components of vehicle control system 420 can be networked in various ways.

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

[0084] Generally, various architectures, including various combinations of software, hardware, circuit logic, sensors, and networks, can be used to implement the various components shown in FIG. 4a. For example, each processor can be implemented as a microprocessor, and each memory can include not only random access memory (RAM) devices that make up the main memory, but also any auxiliary level of memory, such as cache memory, non-volatile or backup memory (e.g., programmable or flash memory), read-only memory, and the like. Also, each memory can be considered to include not only any cache memory within the processor, which is physically located elsewhere in vehicle 410A, but also any storage capacity used as virtual memory (e.g., that stored in a mass storage device or in another computer controller). One or more of the processors shown in FIG. 4a, or a completely separate processor, can be used to implement additional functions other than for autonomous control purposes, such as controlling an entertainment system, operating doors, lighting, convenience functions, etc. in vehicle 410A.

[0085] Also, for additional storage, vehicle 410A can include one or more mass storage devices, such as removable disk drives, hard disk drives, direct access storage devices (DASD), optical drives (e.g., CD drives, DVD drives, etc.), solid state storage drives (SSD), network attached storage, storage area networks, and / or tape drives, and the like.

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

[0087] Also, vehicle 410A may include one or more network interfaces, such as network interface 462, which allows the vehicle 410A to receive environmental and other data for use in autonomous control and communicate information with other computers and electronic devices, including central services such as cloud services, via one or more networks (e.g., local area network (LAN), wide area network (WAN), wireless network, and / or the Internet). Data collected by one or more sensors 430 may be uploaded to computing system 472 via network 470 for additional processing. A timestamp may be added to each instance of vehicle data prior to upload.

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

[0089] Generally, the routines performed to implement the various embodiments described herein may be embodied as part of an operating system or as a particular application, component, program, object, module, or sequence of instructions, or as a subset thereof, and are referred to herein as "program code." The program code may reside at various times in various memories and storage devices and may include one or more instructions that, when read and executed by one or more processors, perform the steps necessary to execute the steps or elements that implement the various aspects of the present disclosure. Embodiments are described in the context of fully functional computers and systems, and the various embodiments described herein can be distributed as a variety of forms of program products, and it should be understood that such embodiments can be implemented independently of the particular type of computer-readable medium used to actually effect the distribution.

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

[0091] Also, the various program codes described below can be identified based on the applications embodied in specific embodiments. However, it should be understood that any of the following specific program nomenclatures are used merely for convenience, and thus, the present disclosure should not be limited to use only in any specific application identified and / or implied by such nomenclature. Further, considering the innumerable ways in which a computer program can be composed of routines, procedures, methods, modules, objects, etc., and the various ways in which program functions can be allocated among the various software layers resident in a general computer (e.g., operating system, library, API, application, applet, etc.), it should be understood that the present disclosure is not limited to the specific structures and allocations of the program functions described herein.

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

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

[0094] FM or phase modulation (PM) LIDAR systems can offer significant advantages compared to conventional LIDAR systems for automotive and / or commercial truck transportation applications. First, in some cases, an object (such as a pedestrian wearing dark clothing) may have a low reflectivity, which is because only a small amount of the light reaching the object (such as 10% or less) is reflected back to the sensor of the FM or PM LIDAR system (such as sensor 430 in FIG. 4a). In other cases, an object (such as a shiny road sign) may have a high reflectivity (such as 10% or more), which is because a large amount of the light reaching the object is reflected back to the sensor of the FM LIDAR system.

[0095] Regardless of the reflectivity of the object, the FM LIDAR system can detect (such as classify, recognize, discover, etc.) the object at a greater distance (such as twice as far) than a conventional LIDAR system. For example, the FM LIDAR system can detect low-reflectivity objects at 300 meters or more and high-reflectivity objects at 400 meters or more.

[0096] To achieve such an improvement in detection capabilities, an FM LIDAR system can use sensors (e.g., sensor 430 in FIG. 4a). In some embodiments, these sensors may be sensitive to single photons, which means that they can detect the minimum amount of light possible. In some applications, an FM LIDAR system can use infrared wavelengths (e.g., 950 nm, 1550 nm, etc.), but is not limited to the range of infrared wavelengths (e.g., near-infrared: 800 nm - 1500 nm, mid-infrared: 1500 nm - 5600 nm, and far-infrared: 5600 nm - 1000000 nm). By operating an FM or PM LIDAR system at infrared wavelengths, the FM or PM LIDAR system can broadcast stronger light pulses or light beams while meeting eye safety standards. Conventional LIDAR systems are often not sensitive to single photons and / or operate only at near-infrared wavelengths, so it is necessary to limit the light output (and distance detection function) for eye safety.

[0097] Therefore, by detecting objects at greater distances, an FM LIDAR system can secure more time to react to unexpected obstacles. In fact, in the case of a large vehicle traveling at high speed (e.g., a commercial truck), even a few milliseconds of extra time can improve safety and convenience.

[0098] Another advantage of the FM LIDAR system is that it instantaneously provides accurate speed for each data point. In some embodiments, the speed measurement is achieved using the Doppler effect that shifts the frequency of the light received from the object based on at least one of the speed in the 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 occurring in road situations where the speed is less than 100 meters per second (m / s), this shift at a wavelength of 1550 nanometers (nm) corresponds to a frequency shift of less than 130 megahertz (MHz). This frequency shift is so small that it is difficult to directly detect in the optical region. However, when using coherent detection in an FMCW, PMCW, or FMQW LIDAR system, the signal can be converted to the RF region so that various signal processing techniques can be used to calculate the frequency shift. This enables the autonomous vehicle control system to process the received data more quickly.

[0099] Also, the FM LIDAR system can more easily distinguish and / or track objects with far - away or sparse data points as instantaneous speed calculations are made. For example, an FM LIDAR sensor (e.g., sensor 430 in FIG. 4a) may receive only a few returns (e.g., hits) for an object 300 m away, but if these returns provide speed values of interest (e.g., moving towards the vehicle at a speed of 70 mph or more), the FM LIDAR system and / or the autonomous vehicle control system can determine individual weights for the probabilities associated with the object.

[0100] The faster identification and / or tracking of the FM LIDAR system provides the autonomous vehicle control system with more time to maneuver the vehicle. Also, by more accurately understanding the moving speed of the object, the autonomous vehicle control system can plan more appropriate responses.

[0101] Another advantage of the FM LIDAR system is that it is less static compared to conventional LIDAR systems. That is, conventional LIDAR systems designed to be more sensitive to light generally experience a degradation in performance under bright sunlight. Also, these systems tend to suffer from 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 drawbacks, vehicles using conventional LIDAR systems often require additional hardware, complex software, and / or more computing power to manage this "noise".

[0102] On the other hand, the FM LIDAR system is specially designed so that each sensor responds only to its own optical characteristics (e.g., light beam, light wave, light pulse), so such problems do not occur. If the returned light does not match the timing, frequency, and / or wavelength of the originally transmitted light, the FM sensor can filter (e.g., remove, ignore, etc.) the data point. Therefore, the FM LIDAR system enables safer and smoother driving by producing (e.g., generating, deriving, etc.) more accurate data with fewer hardware or software requirements.

[0103] Finally, the FM LIDAR system is easier to expand than conventional LIDAR systems. As more autonomous vehicles (e.g., cars, commercial trucks, etc.) appear on the road, vehicles driven by the FM LIDAR system are likely to no longer have to face interference problems due to sensor crosstalk. Also, the FM LIDAR system uses less optical peak power than conventional LIDAR sensors. This allows some or all of the optical components of the FM LIDAR to be manufactured on a single chip, which offers unique advantages as described in this specification.

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

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

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

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

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

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

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

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

[0112] In the field of commercial truck transportation applications, as the weight of the vehicle increases and accordingly a longer stopping distance is required, it is important to effectively detect objects in all ranges. FM LIDAR systems (e.g., FMCW and / or FMQW systems) or PM LIDAR systems are optimal for commercial truck transportation applications due to the aforementioned advantages. Ultimately, commercial trucks equipped with these systems can improve the safety not only of the commercial trucks themselves but also of surrounding vehicles because of their improved ability to safely move people and goods over short or long distances. In various embodiments, these FM or PM LIDAR systems can be used in semi-autonomous application fields where a driver is on board the commercial truck and some functions of the commercial truck operate autonomously using the FM or PM LIDAR system, or in fully autonomous application fields where the commercial truck operates completely by the FM or PM LIDAR system alone or in combination with other vehicle systems.

[0113] 4. Continuous Wave Modulation and Quasi-Continuous Wave Modulation In a LIDAR system using CW modulation, the modulator continuously modulates the laser light. For example, when the modulation period is 10 seconds, the input signal is modulated over the entire 10 seconds. Instead, in the case of a LIDAR system using quasi-CW modulation, the modulator modulates the laser light such that it has both an active part and an inactive part. For example, in the case of a 10-second period, the modulator modulates the laser light for only 8 seconds (also called the "active part") and does not modulate the laser light for 2 seconds (also called the "inactive part"). Thereby, since the modulator does not need to provide a continuous signal, the LIDAR system can reduce power consumption for 2 seconds.

[0114] In the case of frequency-modulated continuous-wave (FMCW) LIDAR for vehicle applications, although FMCW measurement and signal processing methodologies are used, it can be advantageous to operate the LIDAR system using quasi-CW modulation rather than having the optical signal always on (e.g., activated, powered, transmitting, etc.). In some embodiments, the quasi-CW modulation can have a duty cycle of 1% or more and up to 50% or less. If energy is consumed during the off state (e.g., deactivated, powered off, etc.) during the actual measurement time, the signal-to-noise ratio (SNR) can be improved or the requirements for signal processing can be reduced, so that all energy can be consistently integrated over a longer time.

[0115] In the present disclosure, the term "processing logic" can include one or more processors, microprocessors, multi-core processors, application-specific integrated circuits (ASICs), and / or field-programmable gate arrays (FPGAs) for performing the operations disclosed herein. In some embodiments, a memory (not shown) is integrated with the processing logic to store instructions for performing operations and / or storing data. Also, the processing logic can include analog or digital circuits for performing operations according to embodiments of the present disclosure.

[0116] As used herein, "memory" or "memories" may include one or more volatile or non-volatile memory architectures. "Memory" or "memories" can be removable and non-removable media embodied in any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data. Examples of memory technologies include RAM, ROM, EEPROM, flash memory, CD-ROM, DVD, high-definition multimedia / data storage disks or other optical storage, magnetic cassettes, magnetic tapes, magnetic disk storage, other magnetic storage devices or other non-transmission media that can be used to store information for access by a computing device.

[0117] Networks can include all networks or network systems such as peer-to-peer networks, LANs (local area networks), WANs (wide area networks), public networks such as the Internet, private networks, cellular networks, wireless networks, wired networks, wired / wireless combined networks, and satellite networks, but are not limited thereto.

[0118] Communication channels can include or be routed by one or more wired or wireless communications using the IEEE802.11 protocol, Bluetooth, SPI (Serial Peripheral Interface), I2C (Inter-Integrated Circuit), USB (Universal Serial Port), CAN (Controller Area Network), cellular data protocols (e.g., 3G, 4G, LTE, 5G, etc.), optical communication networks, Internet service providers (ISPs), peer-to-peer networks, LANs, WANs, public networks (e.g., "the Internet"), private networks, satellite networks or others.

[0119] The computing device may include a desktop computer, a laptop computer, a tablet, a phablet, a smartphone, a feature phone, a server computer, and the like. The server computer may be located remotely in a data center or stored locally.

[0120] The processes described above are described in terms of computer software and hardware aspects. The described technology may be composed of machine-executable instructions embodied in a tangible or non-transitory machine (e.g., computer) readable storage medium, which, when executed by a machine, cause the machine to perform the described operations. Further, the process can be implemented in hardware such as an application-specific integrated circuit ("ASIC").

[0121] The 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, a network device, a personal digital assistant, a manufacturing tool, any device having one or more sets of processors, etc.). For example, the 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.).

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

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

Claims

1. A LIDAR sensor system, comprising: one or more LIDAR pixels, wherein at least one of the one or more LIDAR pixels comprises: (i) a dual-polarization optical antenna configured to emit a transmit beam having a first polarization direction and (ii) detect a return beam having a second polarization direction; a first receiver configured to generate a first signal in response to receiving the second polarization direction of the return beam and in response to a first local oscillator signal; a second receiver configured to generate a second signal in response to receiving the second polarization direction of the return beam from the dual-polarization optical antenna and in response to a second local oscillator signal.

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

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

4. The single-polarization optical antenna is a one-dimensional (1D) polarization grating coupler. The LIDAR sensor system according to claim 3.

5. The dual-polarization optical antenna is offset from the single-polarization optical antenna by a specific distance. The LIDAR sensor system according to claim 3.

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

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

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

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

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

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

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

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

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

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

Images