WO2023225284A1

WO2023225284A1 - Lidar with switchable local oscillator signals

Info

Publication number: WO2023225284A1
Application number: PCT/US2023/022883
Authority: WO
Inventors: Sen Lin; Andrew Steil MICHAELS
Original assignee: Ours Technology, Llc
Priority date: 2022-05-20
Filing date: 2023-05-19
Publication date: 2023-11-23

Abstract

A light detection and ranging (LIDAR) sensor system includes a plurality of LIDAR pixels and a local oscillator module. The local oscillator module is coupled to the plurality of LIDAR pixels. The local oscillator module includes a first local oscillator input configured to receive a first local oscillator signal and a second local oscillator input configured to receive a second local oscillator signal. The local oscillator module is configured to provide the first local oscillator signal or the second local oscillator signal to a first LIDAR pixel of the plurality of LIDAR pixels.

Description

LIDAR WITH SWITCHABLE LOCAL OSCILLATOR SIGNALS

RELATED APPLICATIONS

[0001] The present application is based on and claims the benefit of United States Non-Provisional Patent Application No. 18/161,441, having a filing date of January 30, 2023, which is a continuation of the United States Non-Provisional Patent Application No. 18/160,817, having a filing date of January 27, 2023, which is a continuation of United States Non-Provisional Patent Application No. 17/750,247, having a filing date of May 20, 2022. The present application is also based on and claims benefit of United States Non-Provisional Patent Application No. 17/845,948, having a filing date of June 21, 2022. All such applications are incorporated by reference herein in their entirety.

BACKGROUND INFORMATION

[0002] Frequency Modulated Continuous Wave (FMCW) light detection and ranging (LIDAR) directly measures range and velocity of an object by transmitting a frequency modulated light beam and detecting a return signal. The automobile industry is currently developing autonomous features for controlling vehicles under certain circumstances. According to SAE International standard J3016, there are 6 levels of autonomy ranging from Level 0 (no autonomy) up to Level 5 (vehicle capable of operation without operator input in all conditions). A vehicle with autonomous features utilizes sensors to sense the environment that the vehicle navigates through. Acquiring and processing data from the sensors allows the vehicle to navigate through its environment.

BRIEF SUMMARY OF THE INVENTION

[0003] Implementations of the disclosure include a light detection and ranging (LIDAR) sensor system including a plurality of LIDAR pixels and a local oscillator module. The local oscillator module is coupled to the plurality of LIDAR pixels. The local oscillator module includes a first local oscillator input configured to receive a first local oscillator signal and a second local oscillator input configured to receive a second local oscillator signal. The local oscillator module is configured to provide the first local oscillator signal and the second local oscillator signal to a first LIDAR pixel of the plurality of LIDAR pixels.

[0004] In an implementation, the LIDAR sensor system includes one or more processors and a transmit beam module. The transmit beam module is configured to receive a transmit beam. The one or more processors are configured to (i) drive the transmit beam module to provide the transmit beam to the first LIDAR pixel and (ii) drive the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to the first LIDAR pixel.

[0005] In an implementation, the one or more processors are further configured to: drive the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to a second LIDAR pixel of the plurality of LIDAR pixels; and drive the transmit beam module to provide the transmit beam to the second LIDAR pixel while the one or more processors drive the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to the second LIDAR pixel.

[0006] In an implementation, the transmit beam module is configured to provide the transmit beam to a particular LIDAR pixel in the plurality of LIDAR pixels.

[0007] In an implementation, the one or more processors are configured to drive the transmit beam module to provide the transmit beam to the first LIDAR pixel while the one or more processors drive the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to the first LIDAR pixel.

[0008] In an implementation, at least the first LIDAR pixel and a second LIDAR pixel in the plurality of LIDAR pixels include: (1) a transmit optical antenna to emit a transmit beam; (2) a receive optical antenna to detect a return beam; (3) a first receiver configured to receive (i) a first polarization orientation of the return beam; and (ii) the first local oscillator signal from local oscillator module; and (4) a second receiver configured to receive (i) a second polarization orientation of the return beam; and (ii) the second local oscillator signal from the local oscillator module.

[0009] In an implementation, the receive optical antenna includes: a first polarization receive grating configured to direct the first polarization orientation of the return beam to the first receiver; and a second polarization receive grating configured to direct the second polarization orientation of the return beam to the second receiver. The first polarization receive grating is spaced apart from the second polarization receive grating.

[0010] In an implementation, the first receiver includes a first optical mixer and the second receiver includes a second optical mixer. [0011] Tn an implementation, the local oscillator module is configured to provide the first local oscillator signal and the second local oscillator signal to only one particular LIDAR pixel in the plurality of LIDAR pixels, at any given time.

[0012] In an implementation, LIDAR sensor system further includes a light source configured to emit near-infrared light and a splitter configured to split the nearinfrared light into a transmit signal and a local oscillator signal. At least one of the first local oscillator signal and the second local oscillator signal is derived from the local oscillator signal.

[0013] In an implementation, the local oscillator module includes at least two optical switches.

[0014] In an implementation, the first local oscillator signal has a first polarization orientation and the second local oscillator signal has a second polarization orientation that is different from the first polarization orientation.

[0015] In an implementation, the first polarization orientation is orthogonal to the second polarization orientation.

[0016] Implementations of the disclosure include an autonomous vehicle control system for an autonomous vehicle including a light detection and ranging (LIDAR) device and one or more processors. The one or more processors are configured to control the autonomous vehicle in response to the beat signals. The LIDAR device includes a plurality of LTDAR pixels configured to generate beat signals and a local oscillator module. The local oscillator module is coupled to the plurality of LIDAR pixels. The local oscillator module includes a first local oscillator input configured to receive a first local oscillator signal and a second local oscillator input configured to receive a second local oscillator signal. The local oscillator module is configured to provide the first local oscillator signal and the second local oscillator signal to a first LIDAR pixel of the plurality of LIDAR pixels.

[0017] In an implementation, the autonomous vehicle control system further includes a transmit beam module configured to receive a transmit beam. The one or more processors are configured to drive (i) the transmit beam module to provide the transmit beam to the first LIDAR pixel and (ii) the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to the first LIDAR pixel.

[0018] In an implementation, the one or more processors are further configured to: drive the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to a second first LIDAR pixel of the plurality of LIDAR pixels; and drive the transmit beam module to provide the transmit beam to the second first LIDAR pixel while the one or more processors drive the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to the second first LIDAR pixel.

[0019] In an implementation, the transmit beam module is configured to provide the transmit beam to a particular LIDAR pixel in the plurality of LIDAR pixels.

[0020] In an implementation, the one or more processors are configured to drive the transmit beam module to provide the transmit beam to the first LIDAR pixel while the one or more processors drive the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to the first LIDAR pixel.

[0021] Implementations of the disclosure include an autonomous vehicle including a light detection and ranging (LIDAR) device and one or more processors configured to control the autonomous vehicle in response to the beat signals. The LIDAR device includes a plurality of LIDAR pixels configured to generate beat signals and a local oscillator module coupled to the plurality of LIDAR pixels. The local oscillator module is coupled to the plurality of LIDAR pixels. The local oscillator module includes a first local oscillator input to receive a first local oscillator signal and a second local oscillator input to receive a second local oscillator signal. The local oscillator module is configured to selectively provide the first local oscillator signal and the second local oscillator signal to a first LIDAR pixel of the plurality of LIDAR pixels.

[0022] Implementations of the disclosure include a light detection and ranging (LIDAR) sensor system. The LIDAR sensor system includes a laser source configured to emit a laser beam. The LIDAR sensor system includes a splitter configured to split the laser beam into a transmit beam and a local oscillator signal. The LIDAR sensor system includes a polarizing module configured to receive the local oscillator signal and generate a first local oscillator signal and a second local oscillator signal that is different from the first local oscillator signal. The LIDAR sensor system includes a plurality of LIDAR pixels. The LIDAR sensor system includes a transmit beam module coupled to the plurality of LIDAR pixels. The LIDAR sensor system includes a local oscillator module coupled to the plurality of LIDAR pixels, the local oscillator module including a first local oscillator input configured to receive the first local oscillator signal and a second local oscillator input configured to receive the second local oscillator signal. The LIDAR sensor system includes one or more processors configured to: simultaneously drive the transmit beam, the first local oscillator signal, and the second local oscillator signal to a particular LIDAR pixel of the plurality of LIDAR pixels one at a time to sequentially scan through the plurality of LIDAR pixels. The LIDAR sensor system includes a power monitor coupled to the first LIDAR pixel, the power monitor configured to detect a quantity of power in the transmit beam provided to the first LIDAR pixel.

[0023] In an implementation, the one or more processors are configured to drive the transmit beam module to provide the transmit beam to the first LIDAR pixel while the one or more processors drive the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to the first LIDAR pixel.

[0024] In an implementation, the first LIDAR pixel includes a first optical antenna configured to emit the transmit beam; a second optical antenna configured to detect a return beam; a first receiver configured to receive (i) a first polarization orientation of the return beam, and (ii) the first local oscillator signal from the local oscillator module; and a second receiver configured to receive (i) a second polarization orientation of the return beam, and (ii) the second local oscillator signal from the local oscillator module.

[0025] In an implementation, the second optical antenna includes a dualpolarization receive grating configured to: (i) direct the first polarization orientation of the return beam to the first receiver, and (ii) direct the second polarization orientation of the return beam to the second receiver.

[0026] Tn an implementation, the second optical antenna includes a first polarization receive grating configured to direct the first polarization orientation of the return beam to the first receiver. The second optical antenna includes a second polarization receive grating configured to direct the second polarization orientation of the return beam to the second receiver. The first polarization receive grating is spaced apart from the second polarization receive grating.

[0027] In an implementation, the first receiver includes a first optical mixer. The second receiver includes a second optical mixer.

[0028] In an implementation, the local oscillator module is configured to provide the first local oscillator signal and the second local oscillator signal to only one particular LIDAR pixel in the plurality of LIDAR pixels, at any given time.

[0029] In an implementation, the local oscillator module includes a plurality of optical switches arranged in a multi-tiered configuration.

[0030] In an implementation, the first local oscillator signal has a first polarization orientation. The second local oscillator signal has a second polarization orientation that is different from the first polarization orientation.

[0031] In an implementation, the first polarization orientation is orthogonal to the second polarization orientation.

[0032] Implementations of the disclosure include an autonomous vehicle control system for an autonomous vehicle. The autonomous vehicle control system includes a light detection and ranging (LIDAR) system. The LIDAR system includes a laser source configured to emit a laser beam. The LIDAR system includes a splitter configured to split the laser beam into a transmit beam and a local oscillator signal. The LIDAR system includes a polarizing module configured to receive the local oscillator signal and generate a first local oscillator signal and a second local oscillator signal that is different from the first local oscillator signal. The LIDAR system includes a plurality of LIDAR pixels. The LIDAR system includes a transmit beam module coupled to the plurality of LIDAR pixels. The LIDAR system includes a local oscillator module coupled to the plurality of LIDAR pixels. The local oscillator module includes a first local oscillator input configured to receive the first local oscillator signal and a second local oscillator input configured to receive the second local oscillator signal. The LIDAR system includes one or more processors configured to: simultaneously drive the transmit beam, the first local oscillator signal, and the second local oscillator signal to a particular LIDAR pixel of the plurality of LIDAR pixels one at a time to sequentially scan through the plurality of LIDAR pixels. The LIDAR system includes a power monitor coupled to the first LIDAR pixel, the power monitor configured to detect a quantity of power in the transmit beam provided to the first LIDAR pixel.

[0033] In an implementation, the one or more processors are configured to drive the transmit beam module to provide the transmit beam to the first LIDAR pixel while the one or more processors drive the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to the first LIDAR pixel.

[0034] Implementations of the disclosure include an autonomous vehicle. The autonomous vehicle includes a light detection and ranging (LIDAR) system. The LIDAR system includes a laser source configured to emit a laser beam. The LIDAR system includes a splitter configured to split the laser beam into a transmit beam and a local oscillator signal. The LIDAR system includes a polarizing module configured to receive the local oscillator signal and generate a first local oscillator signal and a second local oscillator signal that is different from the first local oscillator signal. The LIDAR system includes a plurality of LIDAR pixels. The LIDAR system includes a transmit beam module coupled to the plurality of LIDAR pixels. The LIDAR system includes a local oscillator module coupled to the plurality of LIDAR pixels. The local oscillator module includes a first local oscillator input configured to receive the first local oscillator signal and a second local oscillator input configured to receive the second local oscillator signal. The LIDAR system includes one or more processors configured to: simultaneously drive the transmit beam, the first local oscillator signal, and the second local oscillator signal to a particular LIDAR pixel of the plurality of LIDAR pixels one at a time to sequentially scan through the plurality of LIDAR pixels. The LIDAR system includes a power monitor coupled to the first LIDAR pixel, the power monitor configured to detect a quantity of power in the transmit beam provided to the first LIDAR pixel.

[0035] In an implementation, the power monitor includes a detector.

[0036] In an implementation, the detector includes a photodiode.

[0037] In an implementation, at least one of the local oscillator module or the transmit beam module includes a plurality of optical switches in a multi-tiered configuration.

[0038] In an implementation, the local oscillator module includes a first plurality of optical switches arranged in a first multi-tiered configuration; and the transmit beam module includes a second plurality of optical switches arranged in a second multi-tiered configuration that is different from the first multi-tiered configuration.

[0039] Tn an implementation, the first multi-tiered configuration includes more switches than the second multi-tiered configuration.

[0040] In an implementation, the LIDAR sensor system includes a first waveguide coupled between the polarizing module and the first local oscillator input of the local oscillator module; and a second waveguide coupled between the polarizing module and the second local oscillator input of the local oscillator module.

[0041] In an implementation, the power monitor further includes a first waveguide through which the transmit beam passes and a second waveguide configured to receive a portion of the transmit beam from the first waveguide. The detector is configured to convert the portion of the transmit beam into an electrical signal to support power monitoring.

[0042] Implementations of the disclosure include a light detection and ranging (LIDAR) sensor. The LIDAR sensor includes a light source configured to emit a light beam. The LIDAR sensor includes a splitter configured to split the light beam into a transmit beam and a local oscillator signal. The LIDAR sensor includes a plurality of emitters. The LIDAR sensor includes a switching device configured to receive the transmit beam, the switching device including a plurality of optical switches arranged in a multi-tiered configuration and operable to sequentially deliver the light beam to the plurality of emitters.

[0043] In an implementation, the multi-tiered configuration includes a first tier including a first group of the plurality of optical switches. The multi-tiered configuration includes a second tier including a second group of the plurality of optical switches, the second group including more optical switches than the first group. The multi-tiered configuration includes a third tier including a third group of the plurality of optical switches, the third group including more optical switches than the second group. [0044] Tn an implementation, the first group includes one optical switch, the second group includes two optical switches, and the third group includes four optical switches.

[0045] In an implementation, the switching device further includes an optical device coupling an optical switch in the second group to two optical switches in the third group.

[0046] In an implementation, the optical device includes a waveguide crossing.

[0047] In an implementation, the plurality of optical switches are independently controlled.

[0048] In an implementation, the plurality of optical switches are operable to deliver the transmit beam to the plurality of emitters one at a time.

[0049] In an implementation, the transmit beam emitted by a first emitter of the plurality of emitters reflects off of an object as a return beam that is received by the first emitter.

[0050] In an implementation, the first emitter includes a transmit circuit configured to transmit the transmit beam and a receiver circuit configured to receive the return beam.

[0051] In an implementation, the light source includes a laser.

[0052] In an implementation, the LIDAR sensor includes a local oscillator configured to receive the local oscillator signal. The local oscillator includes a plurality of optical switches arranged in the multi-tiered configuration and operable to sequentially deliver the local oscillator signal to the plurality of emitters. [0053] Tn an implementation, the LIDAR sensor includes a polarization module coupled between the local oscillator and the splitter. The polarization module is configured to receive the local oscillator signal and output a first local oscillator signal and a second local oscillator signal to the local oscillator, the first local oscillator signal having a first polarization orientation and the second local oscillator signal having a second polarization orientation that is different from the first polarization orientation.

[0054] In an implementation, the second polarization orientation is orthogonal to the first polarization orientation.

[0055] In an implementation, the LIDAR sensor includes a first interface optically coupling the switching device to the plurality of emitters and a second interface optically coupling the local oscillator to the plurality of emitters.

[0056] In an implementation, at least a first emitter of the plurality of emitters includes a first optical antenna configured to emit the light beam into a surrounding environment and a second optical antenna configured to detect a return beam.

[0057] In an implementation, the second optical antenna includes a dual polarization optical antenna configured to detect a first polarization orientation of the return beam and a second polarization orientation of the return beam.

[0058] In an implementation, at least the first emitter of the plurality of emitters further includes: a first coherent receiver configured to generate a first signal in response to receiving the first local oscillator signal and the first polarization orientation of the return beam, and a second coherent receiver configured to generate a second signal in response to receiving the second local oscillator signal and the second polarization orientation of the return beam. [0059] Tn an implementation, the LIDAR sensor includes a plurality of power monitors configured to monitor a quantity of power in the transmit beam emitted by a respective emitter of the plurality of emitters.

[0060] Implementations of the disclosure include an autonomous vehicle control system. The autonomous vehicle control system includes a light detection and ranging (LIDAR) system. The LIDAR system includes a light source configured to emit a light beam. The LIDAR system includes a splitter configured to split the light beam into a transmit beam and a local oscillator signal. The LIDAR system includes a plurality of emitters. The LIDAR system includes a switching device configured to receive the transmit beam, the switching device including a plurality of optical switches arranged in a multi-tiered configuration and operable to sequentially deliver the transmit beam to the plurality of emitters.

[0061] Implementations of the disclosure include an autonomous vehicle. The autonomous vehicle includes a light detection and ranging (LIDAR) system. The LIDAR system includes a light source configured to emit a light beam. The LIDAR system includes a splitter configured to split the light beam into a transmit beam and a local oscillator signal. The LIDAR system includes a plurality of emitters. The LIDAR system includes a switching device configured to receive the transmit beam. The switching device includes a plurality of optical switches arranged in a multi-tiered configuration and operable to sequentially deliver the transmit beam to the plurality of emitters.

[0062] Implementations of the disclosure include a light detection and ranging (LIDAR) sensor. The LIDAR sensor includes a light source configured to emit a light beam. The LIDAR sensor includes a plurality of LIDAR pixels respectively including: (i) a first optical antenna configured to transmit the light beam into a surrounding environment; and (ii) a second optical antenna configured to detect a return beam indicative of the light beam reflecting off of an object in the surrounding environment. The LIDAR sensor includes a switching device including a plurality of optical switches arranged in a multi-tiered configuration, the plurality of optical switches operable to sequentially deliver the light beam to a respective LIDAR pixel of the plurality of LIDAR pixels to transmit the light beam into the surrounding environment. The LIDAR sensor includes a local oscillator module configured to receive one or more local oscillator signals and deliver the one or more local oscillator signals to the respective LIDAR pixel.

[0063] In an implementation, the multi-tiered configuration includes: a first tier including a first group of the plurality of optical switches, a second tier including a second group of the plurality of optical switches, the second group including more optical switches than the first group, and a third tier including a third group of the plurality of optical switches, the third group including more optical switches than the second group.

[0064] In an implementation, the first group includes one optical switch, the second group includes two optical switches, and the third group includes four optical switches.

[0065] Tn an implementation, the switching device further includes an optical device coupling an optical switch in the second group to two optical switches in the third group.

[0066] In an implementation, the optical device includes a waveguide crossing. [0067] Tn an implementation, the plurality of optical switches are independently controlled.

[0068] In an implementation, the plurality of optical switches are operable to deliver the light beam to the plurality of LIDAR pixels one at a time.

[0069] In an implementation, the one or more local oscillator signals include a first local oscillator signal having a first polarization and a second local oscillator signal having a second polarization that is different from the first polarization.

[0070] In an implementation, the local oscillator module includes a first local oscillator input configured to receive the first local oscillator signal and a second local oscillator input configured to receive the second local oscillator signal.

[0071] In an implementation, the second polarization is orthogonal to the first polarization.

[0072] In an implementation, the second optical antenna includes a dual polarization optical antenna configured to detect a first polarization orientation of the return beam and a second polarization orientation of the return beam.

[0073] In an implementation, the light source includes a laser and the light beam includes a laser beam.

[0074] In an implementation, the LIDAR sensor includes a power monitor configured to monitor a quantity of power included in the light beam delivered to the respective LIDAR pixel.

[0075] In an implementation, the LIDAR sensor includes one or more processors configured to: (i) drive the switching device to deliver the light beam to the respective LIDAR pixel of the plurality of LIDAR pixels; and (ii) drive the local oscillator module to deliver the one or more local oscillator signals to the respective LIDAR pixel.

[0076] In an implementation, the one or more processors are configured to drive the local oscillator module to deliver the one or more local oscillator signals to the respective LIDAR pixel while the one or more processors are configured to drive the switching device to deliver the light beam to the respective LIDAR pixel.

[0077] In an implementation, the plurality of LIDAR pixels and the local oscillator module are disposed on a substrate.

[0078] In an implementation, the plurality of LIDAR pixels further respectively include a receiver configured to convert the return beam received by the second optical antenna into an electrical signal.

[0079] In an implementation, the receiver includes one or more photodiodes.

[0080] Implementations of the disclosure include an autonomous vehicle control system. The autonomous vehicle control system includes a light detection and ranging (LIDAR) system. The LIDAR system includes a light source configured to emit a light beam. The LIDAR system includes a plurality of LIDAR pixels respectively including (i) a first optical antenna configured to transmit the light beam into a surrounding environment; and (ii) a second optical antenna configured to detect a return beam indicative of the light beam reflecting off of an object in the surrounding environment. The LIDAR system includes a switching device including a plurality of optical switches arranged in a multi-tiered configuration, the plurality of optical switches operable to selectively deliver the light beam to a respective LIDAR pixel of the plurality of LIDAR pixels to transmit the light beam into the surrounding environment. The LIDAR system includes a local oscillator module configured to receive one or more local oscillator signals and deliver the one or more local oscillator signals to the respective LIDAR pixel.

[0081] Implementations of the disclosure include an autonomous vehicle. The autonomous vehicle includes a light detection and ranging (LIDAR) system. The LIDAR system includes a light source configured to emit a light beam. The LIDAR system includes a plurality of LIDAR pixels respectively including (i) a first optical antenna configured to transmit the light beam into a surrounding environment; and (ii) a second optical antenna configured to detect a return beam indicative of the light beam reflecting off of an object in the surrounding environment. The LIDAR system includes a switching device including a plurality of optical switches arranged in a multi-tiered configuration, the plurality of optical switches operable to selectively deliver the light beam to a respective LIDAR pixel of the plurality of LIDAR pixels to transmit the light beam into the surrounding environment. The LIDAR system includes a local oscillator module configured to receive one or more local oscillator signals and deliver the one or more local oscillator signals to the respective LIDAR pixel.

[0082] Implementations of the disclosure include a light detection and ranging (LIDAR) device. The LIDAR device includes a local oscillator network and one or more LIDAR pixels. The local oscillator network is configured to provide a plurality of local oscillator signals in the LIDAR device. The one or more LIDAR pixels are coupled to the local oscillator network. The at least one of the one or more LIDAR pixels includes a transmit optical antenna, a receive optical antenna, and at least one 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 at least one receiver is configured to generate at least one signal based on (i) the return beam and (ii) at least one of the plurality of local oscillator signals. The at least one signal represents a distance to an object.

[0083] In an implementation, the at least one of the plurality of local oscillator signals includes a first local oscillator signal and a second local oscillator signal. The at least one receiver includes a first receiver configured to receive the first local oscillator signal, and the at least one receiver includes a second receiver configured to receive the second local oscillator signal.

[0084] In an implementation, the first local oscillator signal has the first polarization orientation and the second local oscillator signal has the second polarization orientation.

[0085] In an implementation, the at least one signal includes a first signal and a second signal. The first receiver is configured to generate the first signal representing the return beam of the first polarization orientation, and the second receiver is configured to generate the second signal representing the return beam of the second polarization orientation.

[0086] In an implementation, the first receiver includes a first optical mixer and a first diode pair configured to generate the first signal, and the second receiver includes a second optical mixer and a second diode pair configured to generate the second signal. The first signal and the second signal are electrical signals. [0087] Tn an implementation, the receive optical antenna includes a first singlepolarization 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 at least one receiver. The second single-polarization grating coupler is configured to couple the second polarization orientation of the return beam to the at least one receiver.

[0088] In an implementation, the transmit optical antenna includes a third singlepolarization grating coupler configured to emit the transmit beam with the first polarization orientation. The first single-polarization grating coupler is offset from the second single-polarization grating coupler, and the second single-polarization grating coupler is offset from the third single-polarization grating coupler.

[0089] In an implementation, the first single-polarization grating coupler is orthogonal to or can be rotated by approximately 90 degrees with respect to the second single-polarization grating coupler.

[0090] In an implementation, the local oscillator network includes a splitter configured to (i) receive a first local oscillator signal and (ii) provide the plurality of local oscillator signals to respective ones of the plurality of LIDAR pixels.

[0091] In an implementation, the local oscillator network is configured to provide at least two of the plurality of local oscillator signals to each of the plurality of LTD AR pixels

[0092] In an implementation, the LIDAR device further includes at least one passive splitter configured to couple a transmit signal to at least two of the one or more LIDAR pixels. [0093] Tn an implementation, the LTDAR device further includes a plurality of power monitors. One of the plurality of power monitors is coupled to the transmit optical antenna. One of the plurality of power monitors includes at least one photodiode that is configured to generate an electrical output signal representative of a quantity of power of a transmit signal.

[0094] In an implementation, the at least one of the plurality of LIDAR pixels further includes an optical rotator configured to couple a transmit signal to the transmit optical antenna and configured to couple the return beam to the at least one receiver.

[0095] In an implementation, the transmit optical antenna is positioned in a first semiconductor layer, and the receive optical antenna is positioned in a second semiconductor layer that is stacked below the first semiconductor layer.

[0096] In an implementation, the first semiconductor layer includes a group III or a group V element, and the second semiconductor layer is a nitride layer.

[0097] In an implementation, the first polarization orientation is orthogonal to the second polarization orientation.

[0098] Implementations of the disclosure include an autonomous vehicle control system for an autonomous vehicle. The autonomous vehicle control system includes a light detection and ranging (LIDAR) device. The LIDAR device includes a local oscillator network and one or more LIDAR pixels. The local oscillator network is configured to provide a plurality of local oscillator signals in the LTDAR device. The one or more LIDAR pixels is coupled to the local oscillator network. The at least one of the one or more LIDAR pixels includes a transmit optical antenna, a receive optical antenna, and at least one 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 at least one receiver is configured to generate at least one signal based on (i) the return beam and (ii) at least one of the plurality of local oscillator signals. The at least one signal represents a distance to an object.

[0099] In an implementation, the receive optical antenna includes a first singlepolarization 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 at least one receiver, and the second singlepolarization grating coupler is configured to couple the second polarization orientation of the return beam to the at least one receiver.

[0100] In an implementation, the transmit optical antenna is positioned in a first semiconductor layer, and the receive optical antenna is positioned in a second semiconductor layer that is stacked below the first semiconductor layer.

[0101] Implementations of the disclosure include an autonomous vehicle. The autonomous vehicle includes a light detection and ranging (LIDAR) device. The LIDAR device includes a local oscillator network and one or more LIDAR pixels. The local oscillator network is configured to provide a plurality of local oscillator signals in the LIDAR device. The one or more LIDAR pixels are coupled to the local oscillator network. The at least one of the one or more LIDAR pixels include a transmit optical antenna, a receive optical antenna, and at least one 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 1 orientation of the return beam. The at least one receiver is configured to generate at least one signal based on (i) the return beam and (ii) at least one of the plurality of local oscillator signals. The at least one signal represents a distance to an object.

[0102] Implementations of the disclosure include a light detection and ranging (LIDAR) sensor system for a vehicle. The LIDAR sensor system includes a laser source configured to emit a laser beam. The LIDAR sensor system includes a splitter configured to split the laser beam into a transmit beam and a local oscillator signal. The LIDAR sensor system includes a polarizing module configured to receive the local oscillator signal and generate a first local oscillator signal and a second local oscillator signal that is different from the first local oscillator signal. The LIDAR sensor system includes a plurality of LIDAR pixels. The LIDAR sensor system includes a transmit beam module configured to provide the transmit beam to only one LIDAR pixel of the plurality of LIDAR pixels at any given time. The LIDAR sensor system includes a local oscillator module coupled to the plurality of LIDAR pixels, the local oscillator module including a first local oscillator input configured to receive the first local oscillator signal and a second local oscillator input configured to receive the second local oscillator signal. The LIDAR sensor system includes one or more processors configured to: (i) drive the transmit beam module to provide the transmit beam to a first LIDAR pixel of the plurality of LIDAR pixels; and (ii) drive the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to the first LIDAR pixel. The LIDAR sensor system includes a power monitor coupled to the first LIDAR pixel. The power monitor is configured to detect a quantity of power in the transmit beam provided to the first LIDAR pixel. [0103] Tn an implementation, the one or more processors are configured to drive the transmit beam module to provide the transmit beam to the first LIDAR pixel while the one or more processors drive the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to the first LIDAR pixel.

[0104] In an implementation, the first LIDAR pixel includes a first optical antenna configured to emit the transmit beam; a second optical antenna configured to detect a return beam; a first receiver configured to receive (i) a first polarization orientation of the return beam, and (ii) the first local oscillator signal from the local oscillator module; and a second receiver configured to receive (i) a second polarization orientation of the return beam, and (ii) the second local oscillator signal from the local oscillator module.

[0105] In an implementation, the second optical antenna includes a dualpolarization receive grating configured to: (i) direct the first polarization orientation of the return beam to the first receiver, and (ii) direct the second polarization orientation of the return beam to the second receiver.

[0106] In an implementation, the second optical antenna includes a first polarization receive grating configured to direct the first polarization orientation of the return beam to the first receiver; and a second polarization receive grating configured to direct the second polarization orientation of the return beam to the second receiver. The first polarization receive grating is spaced apart from the second polarization receive grating.

[0107] In an implementation, the first receiver includes a first optical mixer, and wherein the second receiver includes a second optical mixer. [0108] Tn an implementation, the local oscillator module is configured to provide the first local oscillator signal and the second local oscillator signal to only one particular LIDAR pixel in the plurality of LIDAR pixels, at any given time.

[0109] In an implementation, the first local oscillator signal has a first polarization orientation. The second local oscillator signal has a second polarization orientation that is different from the first polarization orientation.

[0110] In an implementation, the first polarization orientation is orthogonal to the second polarization orientation.

[0111] In an implementation, at least one of the local oscillator module or the transmit beam module includes a plurality of optical switches in a multi-tiered configuration.

[0112] In an implementation, the local oscillator module includes a first plurality of optical switches arranged in a first multi-tiered configuration. The transmit beam module includes a second plurality of optical switches arranged in a second multi-tiered configuration that is different from the first multi-tiered configuration.

[0113] In an implementation, the first multi-tiered configuration includes more switches than the second multi-tiered configuration.

[0114] In an implementation, the power monitor includes a detector. The power monitor further includes a first waveguide through which the transmit beam passes and a second waveguide configured to receive a portion of the transmit beam from the first waveguide. The detector is configured to convert the portion of the transmit beam into an electrical signal to support power monitoring. [0115] Implementations of the disclosure include an autonomous vehicle control system for an autonomous vehicle. The autonomous vehicle control system includes the light detection and ranging (LIDAR) system of any of the foregoing.

[0116] Implementations of the disclosure include an autonomous vehicle including the light detection and ranging (LIDAR) system of any of the foregoing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0117] Non-limiting and non-exhaustive embodiments of the invention are described with reference to the following figures, wherein like reference numerals refer to like parts throughout the various views unless otherwise specified.

[0118] FIG. 1A illustrates a block diagram of an example of a system environment for autonomous vehicles, in accordance with implementations of the disclosure.

[0119] FIG. IB illustrates a block diagram of an example of a system environment for autonomous commercial trucking vehicles, in accordance with implementations of the disclosure.

[0120] FIG. 1C illustrates a block diagram of an example of a system environment for autonomous commercial trucking vehicles, in accordance with implementations of the disclosure.

[0121] FIG. ID illustrates a block diagram of an example of a system environment for autonomous commercial trucking vehicles, in accordance with implementations of the disclosure.

[0122] FIG. 2 illustrates a LIDAR system including a local oscillator module, in accordance with implementations of the disclosure.

[0123] FIG. 3 illustrates an example diagram of a LIDAR, transceiver that may include portions of components of the LIDAR system of FIG. 2, in accordance with implementations of the disclosure.

[0124] FIG. 4 illustrates an example local oscillator module, in accordance with implementations of the disclosure. [0125] FIG. 5 illustrates an example transmit beam module, in accordance with implementations of the disclosure.

[0126] FIG. 6 illustrates an example LIDAR pixel including a first coherent receiver and a second coherent receiver, in accordance with implementations of the disclosure.

[0127] FIG. 7 illustrates an example coherent receiver, in accordance with implementations of the disclosure.

[0128] FIG. 8 illustrates a process of operating a LIDAR device, in accordance with implementations of the disclosure.

[0129] FIG. 9 illustrates a block diagram of a LIDAR system including a LIDAR transceiver, in accordance with implementations of the disclosure.

[0130] FIG. 10A illustrates a schematic diagram of a LIDAR transceiver having a local oscillator network and a LIDAR pixel array, in accordance with implementations of the disclosure.

[0131] FIG. 10B illustrates a schematic diagram of a LIDAR transceiver having a local oscillator network and a LIDAR pixel array, in accordance with implementations of the disclosure.

[0132] FIG. 11 illustrates a LIDAR pixel having a dual-polarization optical antenna, in accordance with implementations of the disclosure.

[0133] FIGS. 12A and 12B illustrate block diagrams of a stacked configuration of optical antennas for a LIDAR device, in accordance with implementations of the disclosure. DETAILED DESCRIPTION

[0134] Implementations of light detection and ranging (LIDAR) with switchable local oscillator signals are described herein. In the following description, numerous specific details are set forth to provide a thorough understanding of the implementations. One skilled in the relevant art will recognize, however, that the techniques 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 are not shown or described in detail to avoid obscuring certain aspects.

[0135] Reference throughout this specification to “one implementation” or “an implementation” means that a particular feature, structure, or characteristic described in connection with the implementation is included in at least one implementation of the present invention. Thus, the appearances of the phrases “in one implementation” or “in an implementation” in various places throughout this specification are not necessarily all referring to the same implementation. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more implementations.

[0136] Throughout this specification, several terms of art are used. These terms are to take on their ordinary meaning in the art from which they come, unless specifically defined herein or the context of their use would clearly suggest otherwise. For the purposes of this disclosure, the term “autonomous vehicle” includes vehicles with autonomous features at any level of autonomy of the SAE International standard J3016. [0137] Tn aspects of this disclosure, visible light may be defined as having a wavelength range of approximately 380 nm - 700 nm. Non-visible light may be defined as light having wavelengths that are outside the visible light range, such as ultraviolet light and infrared light. Infrared light having a wavelength range of approximately 700 nm - 1 mm includes near-infrared light. In aspects of this disclosure, near-infrared light may be defined as having a wavelength range of approximately 700 nm - 1600 nm.

[0138] Frequency Modulated Continuous Wave (FMCW) LIDAR directly measures range and velocity of an object/target by transmitting a frequency modulated light beam to an object or target. The light that is reflected from the object/target may be combined with a tapped version of the light beam. The frequency of the resulting beat signal is proportional to the distance of the object from the LIDAR system once corrected for the doppler shift that requires a second measurement. The two measurements, which may or may not be performed at the same time, provide both range and velocity information.

[0139] Implementations of the disclosure include a LIDAR system and device that uses switchable local oscillator signals. A LIDAR device may include a plurality of LIDAR pixels. The LIDAR pixels may have a transmit optical antenna for emitting a transmit beam and at least one receive optical antenna for detecting a return beam that is the transmit beam reflecting off of a target in an environment. The LIDAR pixels may have a plurality of optical receivers that receive different local oscillator signals. For instance, a first optical receiver of the LIDAR pixel may receive a first oscillator signal having a first polarization orientation and a second optical receiver of the LIDAR pixel may receive a second local oscillator signal having a second polarization orientation that is different from the first polarization orientation. The first optical receiver may receive a first polarization orientation of the return signal and the second optical receiver may receive a second polarization orientation of the return signal. Previously, a first local oscillator signal and second local oscillator signal may have been provided to each of the LIDAR pixels concurrently. However, this techniques can be a drain on optical power and is also optically noisy, which may translate into weaker signal-to-noise ratio (SNR) for detecting the return beam.

[0140] In implementation of the disclosure, a local oscillator module is configured to receive a first local oscillator signal and a second local oscillator signal. The local oscillator module is configured to selectively provide the first local oscillator signal and the second local oscillator signal to a beam-emitting LIDAR pixel that is in a plurality of LIDAR pixels. A transmit beam (e.g. infrared laser light) may be provided to the beam-emitting LIDAR pixel at the same time that the first local oscillator signal and the second local oscillator signal is provided to the beam-emitting LIDAR pixel. A transmit beam module may be configured to provide the transmit beam to whichever LIDAR pixel in the plurality is the beam-emitting LIDAR pixel. In this way, the transmit beam and the first local oscillator signal and the second local oscillator signal may be selectively provided (in some implementations simultaneously) to one LIDAR pixel at a time in order to scan through a plurality of LIDAR pixels. The beam-emitting LIDAR pixel is the LIDAR pixel, at a given time, that would receive the transmit beam, the first local oscillator signal, and the second local oscillator signal.

[0141] Each LIDAR pixel in the plurality of LIDAR pixels may include 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 a return beam. The first receiver may be configured to receive a first polarization orientation of the return beam and the first local oscillator signal from local oscillator module. The second receiver may be configured to receive a second polarization orientation of the return beam and the second local oscillator signal from local oscillator module. The first local oscillator signal may have a polarization orientation that is orthogonal to the second local oscillator signal. The first receiver and the second receiver may generate a first beat signal and a second beat signal. These beat signals may be utilized to generate a LIDAR image of an environment. These and other implementations are described in more detail in connection with FIGs. 1-12B.

[0142] 1. System Environment for Autonomous Vehicles

[0143] FIG. 1A is a block diagram illustrating an example of a system environment for autonomous vehicles according to some implementations.

[0144] Referring to FIG. 1A, an example autonomous vehicle 110A within which the various techniques disclosed herein may be implemented. The vehicle 110A, for example, may include a powertrain 192 including a prime mover 194 powered by an energy source 196 and capable of providing power to a drivetrain 198, as well as a control system 180 including a direction control 182, a powertrain control 184, and a brake control 186. The vehicle 110A may 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 appreciated that the aforementioned components 180 - 198 can vary widely based upon the type of vehicle within which these components are utilized. [0145] For simplicity, the implementations discussed hereinafter will focus on a wheeled land vehicle such as a car, van, truck, bus, etc. In such implementations, the prime mover 194 may include one or more electric motors and/or an internal combustion engine (among others). The energy source may include, for example, a fuel system (e.g., providing gasoline, diesel, hydrogen, etc.), a battery system, solar panels or other renewable energy source, and/or a fuel cell system. The drivetrain 198 can include wheels and/or tires along with a transmission and/or any other mechanical drive components to convert the output of the prime mover 194 into vehicular motion, as well as one or more brakes configured to controllably stop or slow the vehicle 110A and direction or steering components suitable for controlling the trajectory of the vehicle 110A (e.g., a rack and pinion steering linkage enabling one or more wheels of the vehicle 110A to pivot about a generally vertical axis to vary an angle of the rotational planes of the wheels relative to the longitudinal axis of the vehicle). In some implementations, combinations of powertrains and energy sources may be used (e.g., in the case of electric/gas hybrid vehicles), and in some instances multiple electric motors (e.g., dedicated to individual wheels or axles) may be used as a prime mover.

[0146] The direction control 182 may include one or more actuators and/or sensors for controlling and receiving feedback from the direction or steering components to enable the vehicle 110A to follow a desired trajectory. The powertrain control 184 may be configured to control the output of the powertrain 192, e.g., to control the output power of the prime mover 194, to control a gear of a transmission in the drivetrain 198, etc., thereby controlling a speed and/or direction of the vehicle 110A. The brake control 186 may be configured to control one or more brakes that slow or stop vehicle 11 OA, e.g., disk or drum brakes coupled to the wheels of the vehicle.

[0147] 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 implementations, some of the components can be combined, e.g., where directional control of a vehicle is primarily handled by varying an output of one or more prime movers. Therefore, implementations disclosed herein are not limited to the particular application of the herein-described techniques in an autonomous wheeled land vehicle.

[0148] Various levels of autonomous control over the vehicle 110A can be implemented in a vehicle control system 120, which may include one or more processors 122 and one or more memories 124, with each processor 122 configured to execute program code instructions 126 stored in a memory 124. The processors(s) can include, for example, graphics processing unit(s) (“GPU(s)”)) and/or central processing unit(s) (“CPU(s)”).

[0149] Sensors 130 may include various sensors suitable for collecting information from a vehicle’s surrounding environment for use in controlling the operation of the vehicle. For example, sensors 130 can include radar sensor 134, LIDAR (Light Detection and Ranging) sensor 136, a 3D positioning sensors 138, e.g., any of an accelerometer, a gyroscope, a magnetometer, or a satellite navigation system 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 sensors 138 can be used to determine the location of the vehicle on the Earth using satellite signals. Sensors 130 can include a camera 140 and/or an IMU (inertial measurement unit) 142. The camera 140 can be a monographic or stereographic camera and can record still and/or video images. The IMU 142 can include multiple gyroscopes and accelerometers capable of detecting linear and rotational motion of the vehicle in three directions. One or more encoders (not illustrated), such as wheel encoders may be used to monitor the rotation of one or more wheels of vehicle 110A. Each sensor 130 can output sensor data at various data rates, which may be different than the data rates of other sensors 130.

[0150] The outputs of sensors 130 may be provided to a set of control subsystems 1 0, including, a localization subsystem 152, a planning subsystem 156, a perception subsystem 154, and a control subsystem 158. The localization subsystem 152 can perform functions such as precisely determining the location and orientation (also sometimes referred to as “pose”) of the vehicle 110A within its surrounding environment, and generally within some frame of reference. The location of an autonomous vehicle can be compared with the location of an additional vehicle in the same environment as part of generating labeled autonomous vehicle data. The perception subsystem 154 can perform functions such as detecting, tracking, determining, and/or identifying objects within the environment surrounding vehicle 110A. A machine learning model can be utilized in tracking objects. The planning subsystem 156 can perform functions such as planning a trajectory for vehicle 110A over some timeframe given a desired destination as well as the static and moving objects within the environment. A machine learning can be utilized in planning a vehicle trajectory. The control subsystem 158 can perform functions such as generating suitable control signals for controlling the various controls in the vehicle control system 120 in order to implement the planned trajectory of the vehicle 110A. A machine learning model can be utilized to generate one or more signals to control an autonomous vehicle to implement the planned trajectory.

[0151] It will be appreciated that the collection of components illustrated in FIG. 1A for the vehicle control system 120 is merely exemplary in nature. Individual sensors may be omitted in some implementations. Additionally or alternatively, in some implementations, multiple sensors of types illustrated in FIG. 1 A may be used for redundancy and/or to cover different regions around a vehicle, and other types of sensors may be used. Likewise, different types and/or combinations of control subsystems may be used in other implementations. Further, while subsystems 152 - 158 are illustrated as being separate from processor 122 and memory 124, it will be appreciated that in some implementations, some or all of the functionality of a subsystem 152 - 158 may be implemented with program code instructions 126 resident in one or more memories 124 and executed by one or more processors 122, and that these subsystems 152 - 158 may in some instances be implemented using the same processor(s) and/or memory. Subsystems may be implemented at least in part using various dedicated circuit logic, various processors, various field programmable gate arrays (“FPGA”), various application -specific integrated circuits (“ASIC”), various real time controllers, and the like, as noted above, multiple subsystems may utilize circuitry, processors, sensors, and/or other components. Further, the various components in the vehicle control system 120 may be networked in various manners. [0152] Tn some implementations, the vehicle 110A may also include a secondary vehicle control system (not illustrated), which may be used as a redundant or backup control system for the vehicle 110A. The secondary vehicle control system may be capable of fully operating the autonomous vehicle 110A in the event of an adverse event in the vehicle control system 120, while in other implementations, the secondary vehicle control system may only have limited functionality, e.g., to perform a controlled stop of the vehicle 110A in response to an adverse event detected in the primary vehicle control system 120. In still other implementations, the secondary vehicle control system may be omitted.

[0153] In general, an innumerable number of different architectures, including various combinations of software, hardware, circuit logic, sensors, networks, etc. may be used to implement the various components illustrated in FIG. 1 A. Each processor may be implemented, for example, as a microprocessor and each memory may represent the random access memory (“RAM”) devices comprising a main storage, as well as any supplemental levels of memory, e.g., cache memories, non-volatile or backup memories (e.g., programmable or flash memories), read- only memories, etc. In addition, each memory may be considered to include memory storage physically located elsewhere in the vehicle 110A, e.g., any cache memory in a processor, as well as any storage capacity used as a virtual memory, e.g., as stored on a mass storage device or another computer controller. One or more processors illustrated in FIG. 1 A, or entirely separate processors, may be used to implement additional functionality in the vehicle 110A outside of the purposes of autonomous control, e.g., to control entertainment systems, to operate doors, lights, convenience features, etc. [0154] Tn addition, for additional storage, the vehicle 1 10A may include one or more mass storage devices, e.g., a removable disk drive, a hard disk drive, a direct access storage device (“DASD”), an optical drive (e.g., a CD drive, a DVD drive, etc.), a solid state storage drive (“SSD”), network attached storage, a storage area network, and/or a tape drive, among others.

[0155] Furthermore, the vehicle 110A may include a user interface 164 to enable vehicle 110A to receive a number of inputs from and generate outputs for a user or operator, e.g., one or more displays, touchscreens, voice and/or gesture interfaces, buttons and other tactile controls, etc. Otherwise, user input may be received via another computer or electronic device, e g., via an app on a mobile device or via a web interface.

[0156] Moreover, the vehicle 110A may include one or more network interfaces, e.g., network interface 162, suitable for communicating with one or more networks 170 (e.g., a Local Area Network (“LAN”), a wide area network (“WAN”), a wireless network, and/or the Internet, among others) to permit the communication of information with other computers and electronic device, including, for example, a central service, such as a cloud service, from which the vehicle 110A receives environmental and other data for use in autonomous control thereof. Data collected by the one or more sensors 130 can be uploaded to a computing system 172 via the network 170 for additional processing. A time stamp can be added to each instance of vehicle data prior to uploading.

[0157] Each processor illustrated in FIG. 1 A, as well as various additional controllers and subsystems disclosed herein, generally operates under the control of an operating system and executes or otherwise relies upon various computer software applications, components, programs, objects, modules, data structures, etc., as will be described in greater detail below. Moreover, various applications, components, programs, objects, modules, etc. may also execute on one or more processors in another computer coupled to vehicle 110A via network 170, e.g., in a distributed, cloud-based, or client-server computing environment, whereby the processing required to implement the functions of a computer program may be allocated to multiple computers and/or services over a network.

[0158] In general, 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”. 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 necessary to execute steps or elements embodying the various aspects of the present disclosure. Moreover, while implementations have and hereinafter will be described in the context of fully functioning computers and systems, it will be appreciated that the various implementations described herein are capable of being distributed as a program product in a variety of forms, and that implementations can be implemented regardless of the particular type of computer readable media used to actually carry out the distribution.

[0159] 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- ROMs, DVDs, etc.) among others.

[0160] In addition, various program code described hereinafter may be identified based upon the application within which it is implemented in a specific implementation. However, it should be appreciated that any particular program nomenclature that follows is used merely for convenience, and thus the present disclosure should not be limited to use solely in any specific application identified and/or implied by such nomenclature. Furthermore, given the typically endless number of manners in which computer programs may be organized into routines, procedures, methods, modules, objects, and the like, as well as the various manners in which program functionality may be allocated among various software layers that are resident within a typical computer (e.g., operating systems, libraries, API’s, applications, applets, etc.), it should be appreciated that the present disclosure is not limited to the specific organization and allocation of program functionality described herein.

[0161] The environment illustrated in FIG. 1A is not intended to limit implementations disclosed herein. Indeed, other alternative hardware and/or software environments may be used without departing from the scope of implementations disclosed herein.

[0162] 2. FM LIDAR for Automotive Applications

[0163] A truck can include a LIDAR system (e g., vehicle control system 120 in FIG. 1A, LIDAR system 200 in FIG. 2, etc ). In some implementations, the LIDAR system can use frequency modulation to encode an optical signal and scatter the encoded optical signal into free-space using optics. By detecting the frequency differences between the encoded optical signal and a returned signal reflected back from an object, the frequency modulated (FM) LIDAR system can determine the location of the object and/or precisely measure the velocity of the object using the Doppler effect. An FM LIDAR system may use a continuous wave (referred to as, “FMCW LIDAR” or “coherent FMCW LIDAR”) or a quasi-continuous wave (referred to as, “FMQW LIDAR”). The LIDAR system can use phase modulation (PM) to encode an optical signal and scatters the encoded optical signal into free-space using optics.

[0164] An FM or phase-modulated (PM) LIDAR system may provide substantial advantages over conventional LIDAR systems with respect to automotive and/or commercial trucking applications. To begin, in some instances, an object (e.g., a pedestrian wearing dark clothing) may have a low reflectivity, in that it only reflects back to the sensors (e.g., sensors 130 in FIG. 1 A) of the FM or PM LIDAR system a low amount (e.g., 10% or less) of the light that hit the object. In other instances, an object (e.g., a shiny road sign) may have a high reflectivity (e.g., above 10%), in that it reflects back to the sensors of the FM LIDAR system a high amount of the light that hit the object.

[0165] Regardless of the object’s reflectivity, an FM LIDAR system may be able to detect (e.g., classify, recognize, discover, etc.) the object at greater distances (e.g., 2x) than a conventional LIDAR system. For example, an FM LIDAR system may detect a low reflectivity object beyond 300 meters, and a high reflectivity object beyond 400 meters.

[0166] To achieve such improvements in detection capability, the FM LIDAR system may use sensors (e.g., sensors 130 in FIG. 1A). In some implementations, these sensors can be single photon sensitive, meaning that they can detect the smallest amount of light possible. While an FM LIDAR system may, in some applications, use infrared wavelengths (e.g., 950nm, 1550nm, etc.), it is not limited to the infrared wavelength range (e.g., near infrared: 800nm - 1500nm; middle infrared: 1500nm - 5600nm; and far infrared: 5600nm - l,000,000nm). By operating the FM or PM LIDAR system in 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 single photon sensitive and/or only operate in near infrared wavelengths, requiring them to limit their light output (and distance detection capability) for eye safety reasons.

[0167] Thus, by detecting an object at greater distances, an FM LIDAR system may have more time to react to unexpected obstacles. Indeed, even a few milliseconds of extra time could improve safety and comfort, especially with heavy vehicles (e.g., commercial trucking vehicles) that are driving at highway speeds.

[0168] Another advantage of an FM LIDAR system is that it provides accurate velocity for each data point instantaneously. In some implementations, a velocity measurement is accomplished using the Doppler effect which shifts frequency of the light received from the object based at least one of the velocity in the radial direction (e.g., the direction vector between the object detected and the sensor) or the frequency of the laser signal. For example, for velocities encountered in on-road situations where the velocity is less than 100 meters per second (m/s), this shift at a wavelength of 1550 nanometers (nm) amounts to the frequency shift that is less than 130 megahertz (MHz). This frequency shift is small such 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 such that the frequency shift can be calculated using various signal processing techniques. This enables the autonomous vehicle control system to process incoming data faster.

[0169] Instantaneous velocity calculation also makes it easier for the FM LIDAR system to determine distant or sparse data points as objects and/or track how those objects are moving over time. For example, an FM LIDAR sensor (e.g., sensors 130 in FIG. 1 A) may only receive a few returns (e.g., hits) on an object that is 300m away, but if those return give a velocity value of interest (e.g., moving towards the vehicle at >70 mph), then the FM LIDAR system and/or the autonomous vehicle control system may determine respective weights to probabilities associated with the objects.

[0170] Faster identification and/or tracking of the FM LIDAR system gives an autonomous vehicle control system more time to maneuver a vehicle. A better understanding of how fast objects are moving also allows the autonomous vehicle control system to plan a better reaction.

[0171] Another advantage of an FM LIDAR system is that it has less static compared to conventional LIDAR systems. That is, the conventional LIDAR systems that are designed to be more light-sensitive typically perform poorly in bright sunlight. These systems also tend to suffer from crosstalk (e.g., when sensors get confused by each other's light pulses or light beams) and from self-interference (e.g., when a sensor gets confused by its own previous light pulse or light beam). To overcome these disadvantages, vehicles using the conventional LIDAR systems often need extra hardware, complex software, and/or more computational power to manage this “noise.” [0172] Tn contrast, FM LIDAR systems do not suffer from these types of issues because each sensor is specially designed to respond only to its own light characteristics (e.g., light beams, light waves, light pulses). If the returning light does not match the timing, frequency, and/or wavelength of what was originally transmitted, then the FM sensor can filter (e.g., remove, ignore, etc.) out that data point. As such, FM LIDAR systems produce (e.g., generates, derives, etc.) more accurate data with less hardware or software requirements, enabling safer and smoother driving.

[0173] Lastly, an FM LIDAR system is easier to scale than conventional LIDAR systems. As more self-driving vehicles (e.g., cars, commercial trucks, etc.) show up on the road, those powered by an FM LIDAR system likely will not have to contend with interference issues from sensor crosstalk. Furthermore, an FM LIDAR system uses less optical peak power than conventional LIDAR sensors. As such, some or all of the optical components for an FM LIDAR can be produced on a single chip, which produces its own benefits, as discussed herein.

[0174] 3. Commercial Trucking

[0175] FIG. IB is a block diagram illustrating an example of a system environment for autonomous commercial trucking vehicles, according to some implementations. The environment 100B includes a commercial truck 102B for hauling cargo 106B. In some implementations, the commercial truck 102B may include vehicles configured to long-haul freight transport, regional freight transport, intermodal freight transport (i.e., in which a road-based vehicle is used as one of multiple modes of transportation to move freight), and/or any other road-based freight transport applications. The commercial truck 102B may be a flatbed truck, a refrigerated truck (e g., a reefer truck), a vented van (e.g., dry van), a moving truck, etc. The cargo 106B may be goods and/or produce. The commercial truck 102B may include a trailer to carry the cargo 106B, such as a flatbed trailer, a lowboy trailer, a step deck trailer, an extendable flatbed trailer, a sidekit trailer, etc.

[0176] The environment 100B includes an object 110B (shown in FIG. IB as another vehicle) that is within a distance range that is equal to or less than 30 meters from the truck.

[0177] The commercial truck 102B may include a LIDAR system 104B (e.g., an FM LIDAR system, vehicle control system 120 in FIG. 1 A, etc.) for determining a distance to the object HOB and/or measuring the velocity of the object HOB. Although FIG. IB shows that one LIDAR system 104B is mounted on the front of the commercial truck 102B, the number of LIDAR system and the mounting area of the LIDAR system on the commercial truck are not limited to a particular number or a particular area. The commercial truck 102B may include any number of LIDAR systems 104B (or components thereof, such as sensors, modulators, coherent signal generators, etc.) that are mounted onto any area (e.g., front, back, side, top, bottom, underneath, and/or bottom) of the commercial truck 102B to facilitate the detection of an object in any free- space relative to the commercial truck 102B.

[0178] As shown, the LIDAR system I04B in environment 100B may be configured to detect an object (e g., another vehicle, a bicycle, a tree, street signs, potholes, etc.) at short distances (e.g., 30 meters or less) from the commercial truck

102B. [0179] FIG. 1C is a block diagram illustrating an example of a system environment for autonomous commercial trucking vehicles, according to some implementations. The environment 100C includes the same components (e.g., commercial truck 102B, cargo 106B, LIDAR system 104B, etc.) that are included in environment 100B.

[0180] The environment 100C includes an object 110C (shown in FIG. 1C as another vehicle) that is within a distance range that is (i) more than 30 meters and (ii) equal to or less than 150 meters from the commercial truck 102B. As shown, the LIDAR system 104B in environment 100C may be configured to detect an object (e.g., another vehicle, a bicycle, a tree, street signs, potholes, etc.) at a distance (e.g., 100 meters) from the commercial truck 102B

[0181] FIG. ID is a block diagram illustrating an example of a system environment for autonomous commercial trucking vehicles, according to some implementations. The environment 100D includes the same components (e.g., commercial truck 102B, cargo 106B, LIDAR system 104B, etc.) that are included in environment 100B.

[0182] The environment 100D includes an object HOD (shown in FIG. ID as another vehicle) that is within a distance range that is more than 150 meters from the commercial truck I02B. As shown, the LIDAR system 104B in environment 100D may be configured to detect an object (e g., another vehicle, a bicycle, a tree, street signs, potholes, etc.) at a distance (e.g., 300 meters) from the commercial truck 102B.

[0183] In commercial trucking applications, it is important to effectively detect objects at all ranges due to the increased weight and, accordingly, 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 trucking applications due to the advantages described above. As a result, commercial trucks equipped with such systems may have an enhanced ability to safely move both people and goods across short or long distances, improving the safety of not only the commercial truck but of the surrounding vehicles as well. In various implementations, such FM or PM LIDAR systems can be used in semi-autonomous applications, in which the commercial truck has a driver and some functions of the commercial truck are autonomously operated using the FM or PM LIDAR system, or fully autonomous applications, in which the commercial truck is operated entirely by the FM or LIDAR system, alone or in combination with other vehicle systems.

[01841 4. Continuous Wave Modulation and Quasi-Continuous Wave Modulation

[0185] In a LIDAR system that uses CW modulation, the modulator modulates the laser light continuously. For example, if a modulation cycle is 10 seconds, an input signal is modulated throughout the whole 10 seconds. Instead, in a LIDAR system that uses quasi-CW modulation, the modulator modulates the laser light to have both an active portion and an inactive portion. For example, for a 10 second cycle, the modulator modulates the laser light only for 8 seconds (sometimes referred to as, “the active portion”), but does not modulate the laser light for 2 seconds (sometimes referred to as, “the inactive portion”). By doing this, the LIDAR system may be able to reduce power consumption for the 2 seconds because the modulator does not have to provide a continuous signal. [0186] Tn Frequency Modulated Continuous Wave (FMCW) LTD AR for automotive applications, it may be beneficial to operate the LIDAR system using quasi- CW modulation where FMCW measurement and signal processing methodologies are used, but the light signal is not in the on-state (e.g., enabled, powered, transmitting, etc.) all the time. In some implementations, Quasi-CW modulation can have a duty cycle that is equal to or greater than 1% and up to 50%. If the energy in the off-state (e.g., disabled, powered-down, etc.) can be expended during the actual measurement time then there may be a boost to signal-to-noise ratio (SNR) and/or a reduction in signal processing requirements to coherently integrate all the energy in the longer time scale.

[0187] FIG. 2 illustrates a LIDAR system 200 including a local oscillator module 212, in accordance with implementations of the disclosure. LIDAR system 200 may be an example implementation of LIDAR system 104B (shown in FIG. IB). LIDAR system 200 includes a laser 202, a splitter 204, a polarizing module 206, local oscillator module 212, a transmit beam module 220, a LIDAR pixel array 214, and processing logic 299, in the illustrated implementation of FIG. 2. Splitter 204 may be coupled to laser 202 to receive a transmit signal 210. Splitter 204 may split transmit signal 210 into transmit beam 213 and local oscillator signal 211. Optionally, a polarizing module such as polarizing module 206 may receive local oscillator signal 211 and generate first local oscillator signal 224 and a second local oscillator signal 226. First local oscillator signal 224 and a second local oscillator signal 226 may have a different polarization orientations. In the illustrated implementation, first local oscillator signal 224 and second local oscillator signal 226 have orthogonal polarization orientations since first local oscillator signal 224 is illustrated as S-polarized light (LOS) and second local oscillator signal 226 is illustrated as P-polarized light (LOP) Tn an implementation, first local oscillator signal 224 and a second local oscillator signal 226 have the same polarization orientations. At least one of the first local oscillator signal and the second local oscillator signal may be derived from the local oscillator signal 211.

[0188] Local oscillator module 212 is configured to receive first local oscillator signal 224 at a first local oscillator input 228 and second local oscillator signal 226 at a second local oscillator input 229. Local oscillator module 212 is coupled to the plurality of LIDAR pixels in LIDAR pixel array 214. Local oscillator module 212 is configured to selectively provide the first local oscillator signal 224 and the second local oscillator signal 226 to a beam-emitting LIDAR pixel of the plurality of LIDAR pixels.

[0189] In an implementation, LIDAR pixel array 214 includes eight LIDAR pixels and, at any given time, one of the LIDAR pixels in the LIDAR pixel array 214 is the beam-emitting LIDAR pixel. The beam-emitting LIDAR pixel may also receive the transmit beam by way of optical bus 222. Processing logic 299 may drive the local oscillator module 212 and the transmit beam module 220 to provide the transmit beam 213, the first local oscillator signal 224, and the second local oscillator signal 226 to the same LIDAR pixel (the beam-emitting LIDAR pixel) in LIDAR pixel array 214. Processing logic 299 may drive the local oscillator module 212 and the transmit beam module 220 to sequentially provide the transmit beam 213, the first local oscillator signal 224, and the second local oscillator signal 226 to different LIDAR pixels in the LIDAR pixel array 214 in order to scan through each LIDAR pixel as the beam-emitting LIDAR pixel. In this way, each LIDAR pixel may emit a transmit beam and detect a return beam as a reflection of the transmit beam reflecting off of a target in the environment. Each LIDAR pixel may generate one or more beat signals by detecting the return beam(s) and the beat signals may be utilized to form a LIDAR image.

[0190] Having system 200 provide the transmit beam 213, the first local oscillator signal 224, and the second local oscillator signal 226 to the same LIDAR pixel (instead of providing these signals to all the LIDAR pixels simultaneously) reduces the optical power required to operate LIDAR system 200. Yet another potential advantage is a reduction of optical noise in LIDAR system 200 that may increase the signal-to-noise- ratio (SNR) of the beat signals generated by the LIDAR pixels. The reduction of optical noise from not providing all the optical signals to each LIDAR pixel simultaneously may stem from reduced optical crosstalk between waveguides of adjacent LIDAR pixels, for instance and may help reduce the complexity of electrical signal routing.

Advantageously, reducing the complexity of the electrical signal routing may save on the cost of the conductor (e.g. copper), reduce weight, and allow for reduced size of the LIDAR pixel array. In particular, for autonomous vehicles, the reduction of cost allows the LIDAR system to be deployed in more vehicles and the reduction in weight and size allows the LIDAR pixel arrays to be placed in a greater variety of positions on the autonomous vehicle.

[0191] FIG. 2 illustrates optical bus 216, optical bus 218, and optical bus 222. Optical bus 216 is coupled between local oscillator module 212 and LIDAR pixel array 214. Optical bus 218 is also coupled between local oscillator module 212 and LIDAR pixel array 214. Optical bus 222 is coupled between transmit beam module 220 and LIDAR pixel array 214. Optical bus 216 (LOS 0-7) may include eight waveguides to provide the first local oscillator signal 224 to the eight LIDAR pixels of LIDAR pixel array 214 and optical bus 218 (LOP 0-7) may include eight waveguides to provide the second local oscillator signal 226 to the eight LIDAR pixels of LIDAR pixel array 214. Similarly, optical bus 222 (TX 0-7) may include eight waveguides to provide the transmit beam 213 to the eight LIDAR pixels of LIDAR pixel array 214. As an example, LIDAR pixel array 214 may include any number of LIDAR pixels such as 4, 16, 32, 48, 64, 96, or 128 LIDAR pixels. As another example, LIDAR pixel array 214 may include 3, 9, 28, or 81 LIDAR pixels. As another example, LIDAR pixel array 214 may include 5, 25, or 125 LIDAR pixels. In these examples, different numbers of LIDAR pixels can be selected to achieve desirable loss ranges.

[0192] FIG. 2 also illustrates bus 240 and bus 242. Bus 240 (RXS 0-7) and bus 242 (RXP 0-7) may be electrical busses rather than optical busses. Bus 240 and bus 242 may carry beat signals generated by LIDAR pixels of LIDAR pixel array 214.

[0193] FIG. 3 illustrates an example diagram of a LIDAR transceiver 300 that may include portions of components of LIDAR system 200, in accordance with implementations of the disclosure. LIDAR transceiver 300 includes a local oscillator module 302 that is coupled to provide local oscillator signals to a LIDAR pixel array 304, according to an implementation of the disclosure. Local oscillator module 302 may be configured the same or similarly to local oscillator module 212.

[0194] Local oscillator (LO) module 302 may be coupled to one or more of a number of input ports 306 through waveguides 310 and 312 to receive one or both local oscillator signals LOS and LOP. Local oscillator module 302 may be configured to provide local oscillator signals LOS and LOP to one or more LIDAR pixels of LIDAR pixel array 304, to enable the LIDAR pixels to generate receive signals RXSO-7 and RXPO-7 and provide the signals to a number of output ports 308, in accordance with implementations of the disclosure.

[0195] LIDAR pixel array 304 may include a number of LIDAR pixels positioned along one or two dimensions of the footprint of LIDAR transceiver 300. LIDAR pixel array 304 may be configured the same or similarly to LIDAR pixel array 214. A LIDAR pixel 314 is an example of one or more of the LIDAR pixels of LIDAR pixel array 304, according to an implementation. LIDAR pixel 314 may receive a transmit beam on a port 316, may receive a first local oscillator signal LOS on a port 318, and may receive a second local oscillator signal LOP on a port 320, according to an implementation. Transmit beam module 220 (not illustrated in FIG. 3) may selectively provide the transmit beam to port 316 by way of terminal TX7 of LIDAR transceiver 300. LIDAR pixel 314 may be configured to generate a receive signal RXS and/or a receive signal RXP and may provide one or both of receive signal RXS and RXP to port 322 and port 324, respectively, in accordance with implementations of the disclosure.

[0196] LIDAR pixel 314 may include one or more optical antennas. FIG. 3 illustrates an optical antenna array 326, receiver circuitry 328, and an optical rotator 330, according to an implementation of the disclosure. Optical antenna array 326 may include at least one transmit optical antenna configured to receive a transmit beam and emit the transmit beam into a LIDAR environment. Optical antenna array 326 may include a receive optical antenna configured to detect the return beam. The receive optical antenna may be configured to detect a first polarization orientation of the return beam and a second polarization orientation of the return beam. The first polarization orientation may be orthogonal to the second polarization orientation. Receiver circuitry 328 may be configured to convert optical signals into the electrical signals, e g., receive signal RXS and receive signal RXP. Receiver circuitry 328 may include one or more pairs of photodiodes configured to receive light and generate electrical signals in response to the received light. Optical rotator 330 may be positioned between optical antenna array 326 and receiver circuitry 328. Optical rotator 330 may be configured to provide the transmit signal to optical antenna array 326 and may be configured to provide return signals from return optical antennas to receiver circuitry 328 to support generation of receive signals RXS and RXP.

[0197] LIDAR transceiver 300 may include an array of power monitors configured to detect a quantity of power in each transmit signal provided to LIDAR pixels of LIDAR pixel array 304. The power monitor array may include one power monitor for each LIDAR pixel of LIDAR pixel array 304. Power monitor 332 may be an example of the power monitors of the power monitor array. Power monitor 332 may include a waveguide 334, a waveguide 336, and a photodiode 338. The transmit beam may propagate through waveguide 334, so waveguide 334 may be positioned in-line with transmit signal waveguides. Waveguide 336 may be positioned near waveguide 334 to receive a portion of the transmit signal. Photodiode 338 may be coupled to waveguide 336 and may be configured to convert a portion of the transmit signal into an electrical signal to support power monitoring operations. Transceiver 300 may include a number of ports 340 that are communicatively coupled to the power monitors of the power monitor array and that are configured to provide power monitor outputs externally to transceiver 300. In some implementations, ports 340 may be used to provide control signals from processing logic (e.g. processing logic 299) to drive local oscillator module 302.

[0198] Transceiver 300 receives transmit beams (e.g., TXO, TX1, TX2, TX3, TX4, TX5, TX6, TX7, etc.) on ports 306 that are coupled to LIDAR pixel array 304 through a number of waveguides (e.g., waveguide 342), according to an implementation. Although eight transmit signals (e.g., TXO-7) and 16 receive signals (receive signals RXSO-7 and RXPO-7) are illustrated, more or fewer transmit and receive signals may be implemented in transceiver 300, according to various implementations of the disclosure.

[0199] FIG. 4 illustrates an example local oscillator module 499, in accordance with implementations of the disclosure. Local oscillator module 499 may include a plurality of optical switches such as optical switch 400, 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, and 413. Each optical switch is controlled by a corresponding controlling input X0, XI, X2, X3, X4, X5, X6, X7, X8, X9, X10, XI 1, X12, and X13. The controlling inputs may be coupled to processing logic 299, for example. Processing logic 299 may drive the optical switches by way of their respective controlling inputs to direct the local oscillator signals to particular LIDAR pixels at particular times. In an implementation, processing logic 299 drives the optical switches to direct the local oscillator signals to only one particular LIDAR pixel at a given time. Local oscillator module 499 may be referred to a “2 to 2n” distribution network for its ability to dynamically route two signals to 2n number of ports where n is a numeral. Tn the implementation of FIG. 4, n is eight and there are 16 (2n) output ports. In an implementation, the local oscillator module may be a “3 to 3n” distribution network for its ability to dynamically route three signals to 3n number of ports where n is a numeral. Tn another implementation, the local oscillator module may be a “5 to 5n” distribution network for its ability to dynamically route five signals to 5n number of ports where n is a numeral. In these implementations, a particular distribution network can be selected to achieve desirable dynamic routing and optimal signal processing.

[0200] In FIG. 4, optical switch 400 is configured to receive first local oscillator signal LOS 434 and optical switch 401 is configured to receive second local oscillator signal LOP 436. In FIG. 4, the dashed lines represent waveguides that provide the first local oscillator signal 434 and the solid lines represent waveguides that provide the second local oscillator signal 436. Components 441 in FIG. 4 represent waveguide crossings, in FIG. 4. In some implementations of local oscillator module 499, multiple waveguide levels are included such that waveguides do not necessarily pass over one another and therefore waveguide crossing components 441 are not necessarily required.

[0201] In an implementation, driving a digital high (e g. 3.3 VDC) onto the controlling input causes the optical switch to direct the input light to exit the left output port and driving a digital low (e.g. 0 VDC) onto the controlling input causes the optical switch to direct the input light to exit the right output port. By way of example, to provide first local oscillator signal 434 and second local oscillator signal 436 to a first LIDAR pixel, controlling inputs X0, XI, X2, X3, X6, and X7 are driven to a digital high so that first local oscillator signal 434 is directed to port LOS 480S and second local oscillator signal 436 is directed to port LOP 480P. To provide first local oscillator signal 434 and second local oscillator signal 436 to a second LIDAR pixel, input ports X0, XI, X2, and X3, may be driven to a digital high and input ports X6 and X7 may be driven to a digital low so that first local oscillator signal 434 is directed to port LOS 48 IS and second local oscillator signal 436 is directed to port LOP 481P. Tn some implementations, the signal on controlling inputs XO, XI, X2, X3, X6, and X7 are analog signals. Processing logic 299 may continue driving the controlling inputs of the optical switches to raster scan through the plurality of LIDAR pixels to provide first local oscillator signal 434 and second local oscillator signal 436 to facilitate generating beat signals for a beam-emitting LIDAR pixel. A third, fourth, fifth, sixth, seventh, and eighth LIDAR pixel may receive first local oscillator signal 434 and second local oscillator signal 436 by driving the controlling ports of the optical switches. For example, a third LIDAR pixel may receive first local oscillator signal 434 and second local oscillator signal 436 by way of ports LOS 482S and LOP 482P; a fourth LIDAR pixel may receive first local oscillator signal 434 and second local oscillator signal 436 by way of ports LOS 483 S and LOP 483P; a fifth LIDAR pixel may receive first local oscillator signal 434 and second local oscillator signal 436 by way of ports LOS 484S and LOP 484P; a sixth LIDAR pixel may receive first local oscillator signal 434 and second local oscillator signal 436 by way of ports LOS 485S and LOP 485P; a seventh LIDAR pixel may receive first local oscillator signal 434 and second local oscillator signal 436 by way of ports LOS 486S and LOP 486P; and an eighth LIDAR pixel may receive first local oscillator signal 434 and second local oscillator signal 436 by way of ports LOS 487S and LOP 487P.

[0202] FTG. 5 illustrates an example transmit beam module 599, in accordance with implementations of the disclosure. Transmit beam module 599 may include a plurality of optical switches such as optical switch 500, 501, 502, 503, 504, 505, and 506. Each optical switch is controlled by a corresponding controlling input X20, X21, X22, X23, X24, X25, and X26. The controlling inputs may be coupled to processing logic 299, for example. Processing logic 299 may drive the optical switches by way of their respective controlling inputs to direct the transmit beam to particular LIDAR pixels at particular times. In an implementation, processing logic 299 drives the optical switches to direct the transmit beam to only one particular LIDAR pixel at a given time.

[0203] In FIG. 5, optical switch 500 is configured to receive transmit beam 513. Components 541 in FIG. 5 represent waveguide crossings. In an implementation, driving a digital high (e.g. 3.3 VDC) onto the controlling input cause the optical switch to direct the input light to exit the left output port and driving a digital low (e.g. 0 VDC) onto the controlling input causes the optical switch to direct the input light to exit the right output port. By way of example, to provide transmit beam 513 to a first LIDAR pixel, controlling inputs X20, X21, and X23 are driven to a digital high so that transmit beam 513 is direct to port TX 560. To provide transmit beam 513 to a second LIDAR pixel, input ports X22 and X24 may be driven to a digital high and input port X20 may be driven to a digital low so that transmit beam 513 is directed to port TX 561. Processing logic 299 may continue driving the controlling inputs of the optical switches to raster scan through the plurality of LIDAR pixels to provide transmit beam 513 to facilitate generating beat signals for a beam-emitting LIDAR pixel. A third, fourth, fifth, sixth, seventh, and eighth LIDAR pixel may receive the transmit beam 513 by driving the controlling ports of the optical switches to provide transmit beam 513 to ports TX 562, TX 563, TX 564, TX 565, TX 566, and TX 567.

[0204] FIG. 6 illustrates an example LIDAR pixel 699 including a first coherent receiver 621 and a second coherent receiver 626, in accordance with implementations of the disclosure. LIDAR pixel 699 includes a transmit optical antenna 605, a receive optical antenna 610, a first coherent receiver 621, and a second coherent receiver 626. Transmit optical antenna 605 is configured to emit a transmit beam. The transmit beam may be an infrared transmit beam. The transmit beam may be a near-infrared transmit beam. The transmit beam may be a single defined polarization orientation. In FIG. 6, transmit optical antenna 605 is illustrated as a single-polarization output coupler and may transmit the transmit beam in response to receiving a transmit beam 601 by way of a waveguide 603. The transmit beam 601 may be generated by a laser and the transmit beam emitted by transmit optical antenna 605 may have a very narrow linewidth (e.g. 1 nm or less). Transmit beam 601 may be selectively provided to transmit optical antenna 605 by transmit beam module 220.

[02051 Receive optical antenna 610 is a dual polarization receive optical antenna configured to detect a first polarization orientation of a returning beam and a second polarization orientation of the returning beam, in the illustration of FIG. 6. The returning beam is a reflection of the transmit beam reflecting off a target in an external environment of the LIDAR system 600. The first polarization orientation may be orthogonal to the second polarization orientation. The dual polarization receive optical antenna 610 is configured to couple the first polarization orientation of the returning beam to first coherent receiver 621 by way of waveguide 612 and couple the second polarization orientation of the returning beam to second coherent receiver 626 by way of waveguide 617. In an implementation, receive optical antenna 610 includes a first polarization receive grating configured to direct the first polarization orientation of the return beam to the first coherent receiver 621 and a second polarization receive grating configured to direct the second polarization orientation of the return beam to second coherent receiver 626. In an implementation, the first polarization receive grating is spaced apart from the second polarization receive grating.

[0206] First coherent receiver 621 is configured to generate a first signal 623 in response to receiving the first polarization orientation of the returning beam and a first local oscillator signal 631. The first local oscillator signal 631 may be an optical signal having the first polarization orientation. First local oscillator signal 631 may be selectively provided by local oscillator module 212, for instance. In FIG. 6, the first polarization orientation of the returning beam is received by first coherent receiver 621 from first single-polarization grating coupler 611 by way of waveguide 612 and the first local oscillator signal 631 is received by first coherent receiver 621 by way of waveguide 632. First signal 623 may be an electrical signal provided to processing logic 650 by way of communication channel 622.

[0207] Second coherent receiver 626 is configured to generate a second signal 628 in response to receiving the second polarization orientation of the returning beam and a second local oscillator signal 636. The second local oscillator signal 636 may be an optical signal having the second polarization orientation. Second local oscillator signal 636 may be selectively provided by local oscillator module 212, for instance. In FIG. 6, the second polarization orientation of the returning beam is received by second coherent receiver 626 from second single-polarization grating coupler 616 by way of waveguide 617 and the second local oscillator signal 636 is received by second coherent receiver 626 by way of waveguide 637. Second signal 628 may be an electrical signal provided to processing logic 650 by way of communication channel 627. [0208] Processing logic 650 is configured to generate an image 655 in response to receiving first signal 623 and second signal 628 from first coherent receiver 621 and second coherent receiver 626, respectively. LIDAR system 600 may include an array of LIDAR pixels 699 that are configured to provide first signals (e.g. signal 623) and second signals (e.g. signal 628) to processing logic 650. In this context, processing logic 650 may generate image 655 in response to the first signal and second signals received by processing logic 650 by the plurality of LIDAR pixels 699 in the array of LIDAR pixels.

[0209] FIG. 7 illustrates an example coherent receiver 771, in accordance with implementations of the disclosure. Example coherent receiver 771 of FIG. 7 may be utilized as first coherent receiver 621 and/or second coherent receiver 626, in some implementations. Coherent receiver 771 includes an optical mixer 752, a return beam port 754, a local oscillator port 758 and an output port 762. Optical mixer 752 is configured to combine a return beam signal (RB) with a local oscillator signal (LO) to generate an output signal (OUT), according to an implementation. Optical mixer 752 may be coupled to receive returning beam signal (RB) from waveguide 612 or waveguide 617, for instance, and waveguide 756 provides the return beam signal to optical mixer 752. Optical mixer 752 may be coupled to receive local oscillator signal LO from waveguide 632 or 637, for instance, and waveguide 760 provides the local oscillator signal LO to optical mixer 752. Optical mixer 752 may combine input signals to generate a number of combined output signals OUT1 and OUT2. Output signals OUT1 and OUT2 are provided to a photodiode pair (including photodiodes PD1 and PD2) to convert returning beam signal RB and local oscillator signal LO into output signal OUT. Output signal OUT may be an electrical signal. Output signal OUT may be a beat signal that represents a range and/or velocity of one or more objects in the environment of a LIDAR system. Communication channel 622 or 627 may be coupled to output port 762, for instance.

[0210] FIG. 8 illustrates a process 800 of operating a LIDAR device, in accordance with implementations of the disclosure. The order in which some or all of the process blocks appear in process 800 should not be deemed limiting. Rather, one of ordinary skill in the art having the benefit of the present disclosure will understand that some of the process blocks may be executed in a variety of orders not illustrated, or even in parallel.

[0211] In process block 805, a light source (e.g. laser 202) is illuminated to generate a transmit beam. The transmit beam may be near-infrared light.

[0212] In process block 810, the transmit beam is selectively directed to a transmit antenna (e.g. antenna 605) of a beam-emitting LIDAR pixel among a plurality of LIDAR pixels.

[0213] In process block 815, a first local oscillator signal and a second local oscillator signal are selectively direct to the beam-emitting LIDAR pixel while the transmit beam is selectively directed to the beam-emitting LIDAR pixel.

[0214] In an implementation of process 800, the first local oscillator signal is selectively directed to a first optical mixer of the beam-emitting LIDAR pixel and the second local oscillator signal is selectively directed to a second optical mixer of the beam-emitting LIDAR pixel. The first local oscillator signal may be a first polarization orientation and the second local oscillator signal may be a second polarization orientation different from the first polarization orientation.

[0215] The beam-emitting LIDAR pixel may include a receive optical antenna to detect a return beam and the first optical mixer may be configured to receive the first polarization orientation of the return beam. The second optical mixer may be configured to receive a second polarization orientation of the return beam.

[0216] In an implementation, process 800 further includes (i) selectively directing the transmit beam to a second transmit antenna of a second beam-emitting LIDAR pixel among the plurality of LIDAR pixels and (ii) selectively directing the first local oscillator signal and the second local oscillator signal to the second beam-emitting LIDAR pixel while the transmit beam is selectively directed to the second beamemitting LIDAR pixel.

[0217] In an implementation of process 800, the transmit beam is not directed to the transmit antenna of the beam-emitting LIDAR pixel while the transmit beam is directed to the second transmit antenna of second beam-emitting LIDAR pixel and the first local oscillator signal and the second local oscillator signal are not directed to the beam-emitting LIDAR pixel while the first local oscillator signal and the second local oscillator signal are directed to the second beam-emitting LIDAR pixel.

[0218] 5. Additional Implementations for Continuous Wave Modulation and Quasi-Continuous Wave Modulation

[0219] FIG. 9 illustrates a LIDAR system 1200, in accordance with implementations of the disclosure. LIDAR system 1200 may be an example implementation of LIDAR sensor 136 (shown in FIG. 1A) and LIDAR system 104B (shown in FIG. IB). LIDAR system 1200 includes a laser 1202, a splitter 1204, a polarizer 1206, and a transceiver 1208, in accordance with implementations of the disclosure. Splitter 1204 may be coupled to laser 1202 to receive a transmit signal 1210. Splitter 1204 may split transmit signal 1210 into transmit signals TXO-7 and local oscillator signals LO1 and LO2, according to an embodiment. Splitter 1204 may be configured to provide transmit signal TX 0-7 and local oscillator signals LO1 and LO2 to transceiver 1208 at a number of input ports 1209. Alternatively, splitter 1204 may be coupled to polarizer 1206 and configured to provide a first local oscillator signal 1224 and a second local oscillator signal 1226, which polarizer 1206 converts into an S- polarized local oscillator signal LO1 and a P-polarized local oscillator signal LO2, according to an implementation of the disclosure. In one implementation, local oscillator signals LO1 and LO2 share the same polarization orientation but are used in transceiver 1208 to generate receive signals RXSO-7 and RXPO-7 from receive optical antennas configured to detect different polarizations.

[0220] In some implementations, transceiver 1208 may be configured to receive input signals (e.g., transmit signals TXO-7 and local oscillator signals LO1 and LO2) and may be configured to generate output signals (e.g., receive signals RXSO-7 and RXPO-7) in response to the input signals. In one implementation, transceiver 1208 is configured to operate using one transmit signal TX0 and one local oscillator signal LO1, for example. Transceiver 1208 may include a local oscillator network 1212 and a LIDAR pixel array 1214 that are configured to support scanning and imaging operations of an autonomous vehicle environment. [0221] Tn some implementations, local oscillator network 1212 may be configured to receive one or both local oscillator signals LO1 and LO2 and may be configured to distribute one or both local oscillator signals LO1 and LO2 over a first local oscillator bus 1216 and over a second local oscillator bus 1218. First local oscillator bus 1216 and second local oscillator bus 1218 may include a number of waveguide channels coupled to provide local oscillator signals LO1 and LO2 to LIDAR pixel array 1214. Local oscillator network 1212 may be coupled to LIDAR pixel array 1214 through one or both local oscillator buses 1216 and 1218.

[0222] LIDAR pixel array 1214 may include a number of LIDAR pixels that may each be configured to emit a transmit beam and detect a return beam, in response to transmit signals TXO-7 and local oscillator signals LO1 and LO2, for example. LIDAR pixel array 1214 may be configured to generate a number of receive signals RXSO-7 from a return beam having a first polarization. LIDAR pixel array 1214 may be configured to generate receive signals RXPO-7 from a return beam having a second polarization orientation. LIDAR pixel array 1214 may provide receive signals RXSO-7 on a first return signal bus 1220 and may provide receive signals RXPO-7 on a second return signal bus 1222. Transceiver 1208 may be configured to provide receive signals RXSO-7 and RXPO-7 to a number of output ports 1228. Receive signals RXSO-7 and RXPO-7 may be used by processing logic to generate image data and/or images representative of objects in a LTD AR operating environment, in accordance with implementations of the disclosure.

[0223] Although transceiver 1208 is described in terms of eight transmit signals and 16 receive signals, it is to be understood that fewer (e g., one or two) or more (e.g., hundreds or thousands) transmit or receive signals may be used, in accordance with various implementations of the disclosure.

[0224] FIG. 10A illustrates an example of a simplified schematic diagram of a LIDAR transceiver 1300, in accordance with implementations of the disclosure. LIDAR transceiver 1300 includes a local oscillator network 1302 that is coupled to provide local oscillator signals to a LIDAR pixel array 1304, according to an implementation of the disclosure.

[0225] In some implementations, local oscillator (LO) network 1302 may be coupled one or more of a number of input ports 1306 through waveguides 1310 and 1312 to receive one or both local oscillator signals LO1 and LO2. Local oscillator network 1302 may be configured to provide local oscillator signals LO1 and LO2 to one or more LIDAR pixels of LIDAR pixel array 1304, to enable the LIDAR pixels to generate receive signals RXS0-7 and RXPO-7 and provide the signals to a number of output ports 1308, in accordance with implementations of the disclosure.

[0226] In some implementations, LIDAR pixel array 1304 may include a number of LIDAR pixels positioned along one or two dimensions of the footprint of LIDAR transceiver 1300. A LIDAR pixel 1314 is an example of one or more of the LIDAR pixels of LIDAR pixel array 1304, according to an implementation. LIDAR pixel 1314 may receive a transmit signal on a port 1316, may receive a local oscillator signal LO1 on a port 1318, and may receive a local oscillator signal LO2 on a port 1320, according to an implementation. LIDAR pixel 1314 may be configured to generate a receive signal RXS and/or a receive signal RXP and may provide one or both of receive signal RXS and RXP to port 1322 and port 1324, respectively, in accordance with implementations of the disclosure. In one implementation, LIDAR pixel 1314 receives a transmit signal, receives one local oscillator signal, and provides a single receive signal.

[0227] LIDAR pixel 1314 may include an optical antenna array 1326, receiver circuitry 1328, and an optical rotator 1330, according to an implementation of the disclosure. Optical antenna array 1326 may include at least one transmit optical antenna configured to receive a transmit signal and emit a transmit beam into a LIDAR environment. Optical antenna array 1326 may include a first receive optical antenna configured to detect a first polarization orientation of a return beam, may include a second receive optical antenna configured to detect a second polarization orientation of a return beam, or may include both the first receive optical antenna and the second receive optical antenna. The first polarization orientation may be orthogonal to the second polarization orientation. Receiver circuitry 1328 may be configured to convert optical signals into the electrical signals, e.g., receive signal RXS and receive signal RXP. Receiver circuitry 1328 may include one or more pairs of photodiodes configured to receive light and generate electrical signals in response to the received light. Optical rotator 1330 may be positioned between optical antenna array 1326 and receiver circuitry 1328. Optical rotator 1330 may be configured to provide the transmit signal to optical antenna array 1326 and may be configured to provide return signals from return optical antennas to receiver circuitry 1328 to support generation of receive signals RXS and RXP. Optical rotator 1330 may be implemented as a polarized beam splitter within a waveguide but that is configured to operate as a rotator to provide transmit signals to the transmit antenna and to provide receive signals to receiver circuitry (e.g., optical mixers and/or photodiodes). [0228] Tn some implementations, LTD AR transceiver 1300 may include an array of power monitors configured to detect a quantity of power in each transmit signal provided to LIDAR pixels of LIDAR pixel array 1304. The power monitor array may include one power monitor for each LIDAR pixel of LIDAR pixel array 1304. Power monitor 1332 may be an example of the power monitors of the power monitor array. Power monitor 1332 may include a waveguide 1334, a waveguide 1336, and a photodiode 1338. The transmit signal may propagate through waveguide 1334, so waveguide 1334 may be positioned in-line with transmit signal waveguides. Waveguide 1336 may be positioned near waveguide 1334 to receive a portion of the transmit signal. Photodiode 1338 may be coupled to waveguide 1336 and may be configured to convert a portion of the transmit signal into an electrical signal to support power monitoring operations. LIDAR transceiver 1300 may include a number of output ports 1340 that are communicatively coupled to the power monitors of the power monitor array and that are configured to provide power monitor outputs externally to LIDAR transceiver 1300.

[0229] LIDAR transceiver 1300 receives transmit signals (e.g., TX0, TX1, TX2, TX3, TX4, TX5, TX6, TX7, etc.) some of ports 1306 that are coupled to LIDAR pixel array 1304 through a number of waveguides (e.g., waveguide 1342), according to an implementation. Although eight transmit signals (e.g., TXO-7) and 16 receive signals (receive signals RXSO-7 and RXPO-7) are illustrated, more or fewer transmit and receive signals may be implemented in LTDAR transceiver 1300, according to various implementations of the disclosure.

[0230] FIG. 10B illustrates a LIDAR transceiver 1350, in accordance with implementations of the disclosure. LIDAR transceiver 1350 may include a splitter 1352 and a splitter 1354 configured to distribute transmit signals from input ports 1306. Splitter 1352 and splitter 1354 may be implemented as passive splitters that include a number of optical splitters configured to receive one optical signal and divide the optical signal into several output ports (e.g., four ports), to support operation of LIDAR pixels of LIDAR pixel array 1304. Splitters 1352 and 1354 may be l-to-4 splitters or may be configured to split a transmit signal into many more signals (e.g., 8, 16, 32, 64, etc.), according to various implementations. Use of splitters 1352 and 1354 may reduce noise caused by cross-talk and may ease the burden associated with routing waveguides within LIDAR transceiver 1350.

[0231] FIG. 11 illustrates a LIDAR system 1400 including a LIDAR pixel 1499, in accordance with implementations of the disclosure. LIDAR pixel 1499 may include an optical antenna array 1460, which may be an implementation of optical antenna array 1326 (shown in FIGS. 10A and 10B). Optical antenna array 1460 may include a transmit optical antenna 1405, a receive optical antenna 1410, a first coherent receiver 1421 and a second coherent receiver 1426. However, the present invention is not limited to the particular LIDAR pixel architecture shown in FIG. 11. Any suitable chip design architecture can be used to implement a LIDAR pixel. For example, transmit and receive optical antennas can be implemented as a single module or a single integrated chip or implemented as separate modules or chips. As another example, first and second coherent receivers can be implemented as a single module or a single integrated chip or implemented as separate modules or chips. Transmit optical antenna 1405 can be configured to emit a transmit beam. The transmit beam may be an infrared transmit beam. The transmit beam may be a near-infrared transmit beam. The transmit beam may be a single defined polarization orientation. Tn FTG. 1 1, transmit optical antenna 1405 is illustrated as a single-polarization output coupler and may transmit the transmit beam in response to receiving a transmit signal 1401 by way of a waveguide 1403, according to an implementation. Transmit signal 1401 may be generated by a laser and the transmit beam emitted by transmit optical antenna 1405 may have a very narrow linewidth (e.g., 1 nm or less).

[0232] In some implementations, receive optical antenna 1410 can be a dualpolarization 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 can be a reflection of the transmit beam reflecting off an object in an external environment of LIDAR system 1400. The first polarization orientation may be orthogonal to the second polarization orientation. In some implementations, the orthogonality can have a margin rage above 0 to 10%. For example, if the first polarization orientation has a degree with reference to the second polarization orientation between 80 and 100 degrees, it can be defined as orthogonal. The first polarization orientation may be s-polarization, and the second polarization orientation may be p- polarization, or vice-versa. In FIG. 11, receive optical antenna 1410 includes a first single-polarization grating coupler 1411 and a second single-polarization grating coupler 1416. First single-polarization grating coupler 1411 can be configured to couple the first polarization orientation of the return beam to first coherent receiver 1421 by way of waveguide 1412. Second single-polarization grating coupler 1416 can be configured to couple the second polarization orientation of the return beam to second coherent receiver 1426 by way of waveguide 1417. Transmit optical antenna 1405 may emit the transmit beam with either the second polarization orientation, as illustrated, or may be configured to emit the transmit beam with the first polarization orientation.

[0233] First single-polarization grating coupler 1411 may be rotated with respect to the second single-polarization grating coupler 1416. In the particular illustrated implementation of FIG. 11, first single-polarization grating coupler 1411 is rotated with respect to the second single-polarization grating coupler 1416 by 90 degrees. The illustrated single-polarization output coupler of transmit optical antenna 1405 may be rotated with respect to the first single-polarization grating coupler 1411 and may include a similar orientation as second single-polarization grating coupler 1416. In particular, first single-polarization grating coupler 1411 may be rotated +45 degrees, transmit optical antenna 1405 may be rotated -45 degrees, and second single-polarization grating coupler 1416 may be rotated -45 degrees, according to an implementation.

[0234] In some implementations, transmit optical antenna 1405, first singlepolarization grating coupler 1411, and second single-polarization grating coupler 1416 may be positioned in a one-dimensional (ID) line to support receiving return beams (e.g., from a rotating mirror) that may impact optical antenna array 1460 at locations offset from transmit optical antenna 405, e.g., due to the pitch-catch nature of transmitting and receiving LIDAR signals with a rotating mirror). For example, first single-polarization grating coupler 1411 may be offset from transmit optical antenna 1405 by a distance DI , and second single-polarization grating coupler 1416 may be positioned between first single-polarization grating coupler 1411 and transmit optical antenna 1405. Second single-polarization grating coupler 1416 may be offset in optical antenna array 1460 by a second distance D2 from transmit optical antenna 1405. First single-polarization grating coupler 141 1 may be offset from second single-polarization grating coupler 1416 by a third distance D3.

[0235] In some implementations, first coherent receiver 1421 may be configured to generate a first signal 1423 in response to receiving the first polarization orientation of the return beam and a first local oscillator signal 1431. The first local oscillator signal 1431 may be an optical signal having the first polarization orientation and may be local oscillator signal LO1 In FIG. 11, the first polarization orientation of the return beam may be received by first coherent receiver 1421 from first single-polarization grating coupler 1411 by way of waveguide 1412, and first local oscillator signal 1431 may be received by first coherent receiver 1421 by way of waveguide 432. First signal 1423 may be an electrical signal provided to processing logic 1450 by way of communication channel 1422.

[0236] In some implementations, first coherent receiver 1421 may include an optical mixer 1462 and photodiode pair 1464 for converting the received optical signal into an electrical signal. Optical mixer 1462 may be coupled to receive local oscillator signal LO1 and the signal representing the first polarization orientation of the return beam from first single-polarization grating coupler 1411. Optical mixer 1462 may be coupled to photodiode pair 1464 to provide a mixed output signal. Photodiode pair 1464 may be configured to generate first signal 1423 and provide first signal 1423 to processing logic 1450 by way of communication channel 1422. First signal 1423 may be an example of receive signal RXS (e.g., shown in FIGS. 10A and 10B). The number of output signals from an optical mixer can be any suitable number, not limited to a particular number. [0237] Tn some implementations, second coherent receiver 1426 can be configured to generate a second signal 1428 in response to receiving the second polarization orientation of the return beam and a second local oscillator signal 1436. The second local oscillator signal 1436 may be an optical signal having the second polarization orientation and may be local oscillator signal LO2. In FIG. 11, the second polarization orientation of the return beam can be received by second coherent receiver 1426 from second single-polarization grating coupler 1416 by way of waveguide 1417, and second local oscillator signal 1436 is received by second coherent receiver 1426 by way of waveguide 1437. Second signal 1428 may be an electrical signal provided to processing logic 1450 by way of communication channel 1427.

[0238] In some implementations, second coherent receiver 1426 may include an optical mixer 1466 and photodiode pair 1468 for converting the received optical signal into an electrical signal. Optical mixer 1466 may be coupled to receive local oscillator signal LO2 and the signal representing the second polarization orientation of the return beam from second single-polarization grating coupler 1416. Optical mixer 1466 may be coupled to photodiode pair 1468 to provide a mixed output signal. Photodiode pair 1468 may be configured to generate second signal 1428 and provide second signal 1428 to processing logic 1450 by way of communication channel 1427. Second signal 1428 may be an example of receive signal RXP (e.g., shown in FIGS. 10A and 10B). The number of output signals from an optical mixer can be any suitable number, not limited to a particular number.

[0239] In some embodiments, the received optical signals, the transmit signal

(prior to emission), and the local oscillator signals may have the same polarization orientation while on-chip (e.g., while propagating through waveguides). One or more of the optical antennae may be configured to change the polarization orientation (e.g., the rotation) of the return beam and of the transmit beam to be one or more specific polarization orientations. For example, an optical antenna may be configured to convert a return beam having a first polarization orientation into a waveguide as a return signal having a second or third polarization orientation. As another example, a transmit signal may have a third orientation while in a waveguide and an optical antenna may be configured to couple the transmit signal into free-space as a transmit beam having a first or second polarization orientation.

[0240] Processing logic 1450 can be configured to generate an image 1455 in response to receiving first signal 1423 and second signal 1428 from first coherent receiver 1421 and second coherent receiver 1426, respectively. LIDAR system 1400 may include an array of LIDAR pixels 1499 that are configured to provide first signals (e.g., signal 1423) and second signals (e.g. signal 1428) to processing logic 1450. In this context, processing logic 1450 may generate image 1455 in response to the first signal and second signals received by processing logic 1450 by the plurality of LIDAR pixels 1499 in the array of LIDAR pixels.

[0241] In an example of operation, transmit signal 1401 may be emitted into free space as the transmit beam by transmit optical antenna 1405. The transmit beam may propagate through one or more lenses and be deflected by a rotating mirror, and then propagate through the external environment until encountering an object. A portion of the transmit beam that encounters the object may be reflected back toward LIDAR system 1400 and LIDAR pixel 1499 as the return beam. The return beam may reflect off the rotating mirror and propagate through the one or more lenses but be offset relative to transmit optical antenna 1405 due to the time difference in the rotation of the mirror. To compensate for this offset, components of receive optical antenna 1410 may be offset from transmit optical antenna 1405.

[0242] FIGS. 12A and 12B illustrate simplified block diagrams of LIDAR devices having stacked antenna configurations, in accordance with implementations of the disclosure. FIG. 12A illustrates an example of a LIDAR, device 1500 having a first semiconductor layer 1502 stacked on top of a second semiconductor layer 1504. LIDAR device 1500 may include a transmit optical antenna 1506 and a receive optical antenna 1508. Transmit optical antenna 1506 is an example implementation of transmit optical antenna 1405 (shown in FIG. 11) and may be configured to emit a transmit beam having a second polarization orientation. Receive optical antenna 1508 may be an example implementation of second single-polarization grating coupler 1416 (shown in FIG. 11) and may be configured to detect a return beam having a second polarization orientation. Second semiconductor layer 1504 includes a second receive optical antenna 1510 that may be an example implementation of first single-polarization grating coupler 1411 (shown in FIG. 11) and that may be configured to detect a return beam having a first polarization orientation. Receive optical antenna 1508 may be offset from transmit optical antenna 1506 and may be positioned in a first semiconductor layer that is stacked on top of a second semiconductor layer. First semiconductor layer 1502 may be an alloy formed from one or more of group III or group V elements from the periodic table. Second semiconductor layer 1504 may be formed from silicon substrate or from nitride. [0243] FTG. 1 IB illustrates an example of a LIDAR device 1550 having a first semiconductor layer 1552 stacked on top of a second semiconductor layer 1554 and configured to provide stacked optical antenna LIDAR operations, in accordance with implementations of the disclosure. First semiconductor layer 1552 may include transmit optical antenna 1506, and second semiconductor layer 1554 may include receive optical antenna 1508 and receive optical antenna 1510 offset from each other and positioned to receive a LIDAR return beam through first semiconductor layer 1552, in accordance with implementations of the disclosure.

[0244] The term “processing logic” (e.g. processing logic 299 or processing logic 650) in this disclosure may include one or more processors, microprocessors, multi-core processors, Application-specific integrated circuits (ASIC), and/or Field Programmable Gate Arrays (FPGAs) to execute operations disclosed herein. In some embodiments, memories (not illustrated) are integrated into the processing logic to store instructions to execute operations and/or store data. Processing logic may also include analog or digital circuitry to perform the operations in accordance with embodiments of the disclosure.

[0245] A “memory” or “memories” described in this disclosure may include one or more volatile or non-volatile memory architectures. The “memory” or “memories” may be removable and non-removable media implemented in any method or technology for storage of information such as computer-readable instructions, data structures, program modules, or other data. Example memory technologies may include RAM, ROM, EEPROM, flash memory, CD-ROM, digital versatile disks (DVD), high- definition multimedia/data storage disks, or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information for access by a computing device.

[0246] Networks may 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 wireless and wired combination network; and a satellite network.

[0247] Communication channels may include or be routed through one or more wired or wireless communication utilizing IEEE 802.11 protocols, 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), optical communication networks, Internet Service Providers (ISPs), a peer-to-peer network, a Local Area Network (LAN), a Wide Area Network (WAN), a public network (e.g. “the Internet”), a private network, a satellite network, or otherwise.

[0248] A computing device may include a desktop computer, a laptop computer, a tablet, a phablet, a smartphone, a feature phone, a server computer, or otherwise. A server computer may be located remotely in a data center or be stored locally.

[0249] The processes explained above are described in terms of computer software and hardware. The techniques described may constitute machine-executable instructions embodied within a tangible or non-transitory machine (e.g., computer) readable storage medium, that when executed by a machine will cause the machine to perform the operations described. Additionally, the processes may be embodied within hardware, such as an application specific integrated circuit (“ASIC”) or otherwise.

[0250] 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.).

[0251] The above description of illustrated embodiments of the invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes, various modifications are possible within the scope of the invention, as those skilled in the relevant art will recognize.

[0252] These modifications can be made to the invention in light of the above detailed description. The terms used in the following claims should not be construed to limit the invention to the specific embodiments disclosed in the specification. Rather, the scope of the invention is to be determined entirely by the following claims, which are to be construed in accordance with established doctrines of claim interpretation.

Claims

CLAIMS What is claimed is:

1. A light detection and ranging (LIDAR) sensor system for a vehicle, the LIDAR sensor system comprising: a laser source configured to emit a laser beam; a splitter configured to split the laser beam into a transmit beam and a local oscillator signal; a polarizing module configured to receive the local oscillator signal and generate a first local oscillator signal and a second local oscillator signal that is different from the first local oscillator signal; a plurality of LIDAR pixels; a transmit beam module configured to provide the transmit beam to only one LIDAR pixel of the plurality of LIDAR pixels at any given time; a local oscillator module coupled to the plurality of LIDAR pixels, the local oscillator module comprising a first local oscillator input configured to receive the first local oscillator signal and a second local oscillator input configured to receive the second local oscillator signal; one or more processors configured to: (i) drive the transmit beam module to provide the transmit beam to a first LIDAR pixel of the plurality of LIDAR pixels; and (ii) drive the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to the first LIDAR pixel; and a power monitor coupled to the first LIDAR pixel, the power monitor configured to detect a quantity of power in the transmit beam provided to the first LIDAR pixel.

2. The LIDAR sensor system of claim 1, wherein the one or more processors are configured to drive the transmit beam module to provide the transmit beam to the first LIDAR pixel while the one or more processors drive the local oscillator module to provide the first local oscillator signal and the second local oscillator signal to the first LIDAR pixel

3. The LIDAR sensor system of any of claims 1 or 2, wherein the first LIDAR pixel comprises: a first optical antenna configured to emit the transmit beam; a second optical antenna configured to detect a return beam; a first receiver configured to receive (i) a first polarization orientation of the return beam; and (ii) the first local oscillator signal from the local oscillator module; and a second receiver configured to receive (i) a second polarization orientation of the return beam; and (ii) the second local oscillator signal from the local oscillator module.

4. The LIDAR sensor system of claim 3, wherein the second optical antenna comprises a dual-polarization receive grating configured to: (i) direct the first polarization orientation of the return beam to the first receiver; and (ii) direct the second polarization orientation of the return beam to the second receiver.

5. The LIDAR sensor system of any of claims 3 or 4, wherein the second optical antenna comprises: a first polarization receive grating configured to direct the first polarization orientation of the return beam to the first receiver; and a second polarization receive grating configured to direct the second polarization orientation of the return beam to the second receiver, wherein the first polarization receive grating is spaced apart from the second polarization receive grating.

6. The LIDAR sensor system of any of claims 3 to 5, wherein the first receiver includes a first optical mixer, and wherein the second receiver includes a second optical mixer.

7. The LIDAR sensor system of any of claims 1 to 6, wherein the local oscillator module is configured to provide the first local oscillator signal and the second local oscillator signal to only one particular LIDAR pixel in the plurality of LIDAR pixels, at any given time.

8. The LIDAR sensor system of any of claims 1 to 8, wherein the first local oscillator signal has a first polarization orientation, and wherein the second local oscillator signal has a second polarization orientation that is different from the first polarization orientation.

9. The LIDAR sensor system of claim 8, wherein the first polarization orientation is orthogonal to the second polarization orientation.

10. The LIDAR sensor system of any of claims 1 to 9, wherein at least one of the local oscillator module or the transmit beam module comprises a plurality of optical switches in a multi-tiered configuration.

11. The LIDAR sensor system of claim 10, wherein: the local oscillator module comprises a first plurality of optical switches arranged in a first multi-tiered configuration; and the transmit beam module comprises a second plurality of optical switches arranged in a second multi-tiered configuration that is different from the first multitiered configuration.

12. The LIDAR sensor system of claim 11, wherein the first multi-tiered configuration includes more switches than the second multi-tiered configuration.

13. The LIDAR sensor system of any of claims 1 to 12, wherein the power monitor comprises a detector, wherein the power monitor further comprises a first waveguide through which the transmit beam passes and a second waveguide configured to receive a portion of the transmit beam from the first waveguide, and wherein the detector is configured to covert the portion of the transmit beam into an electrical signal to support power monitoring.

14. An autonomous vehicle control system for an autonomous vehicle, the autonomous vehicle control system comprising the light detection and ranging (LIDAR) system of any of claims 1 to 13.

15. An autonomous vehicle comprising the light detection and ranging (LIDAR) system of any of claims 1 to 13.