Radar with a switchable local oscillator signal

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 among the plurality of LIDAR pixels.

Description

Technical Field

[0001] Related Applications This application claims the benefit of U.S. Patent Application No. 18 / 161,441, filed Jan. 30, 2023, which is a continuation of U.S. Patent Application No. 18 / 160,817, filed Jan. 27, 2023, which is a continuation of U.S. Patent Application No. 17 / 750,247, filed May 20, 2022. This application also claims the benefit of U.S. Patent Application No. 17 / 845,948, filed Jun. 21, 2022. All of these applications are incorporated by reference in their entirety into this application.

Background Art

[0002] Frequency-modulated continuous-wave (FMCW) optical detection and ranging (LIDAR) transmits a frequency-modulated optical beam and detects the return signal to directly measure the distance and velocity of an object. Currently, the automotive industry is developing autonomous functions for controlling vehicles in certain situations. According to the SAE International standard J3016, there is a range of six levels of autonomy, from level 0 (no autonomy) to level 5 (a vehicle that can be operated without driver input under all conditions). Vehicles with autonomous functions use sensors to detect the environment in which the vehicle is traveling. The collection and processing of sensor data enables the vehicle to drive while exploring the environment.

Summary of the Invention

Means for Solving the Problems

[0003] Embodiments of the present disclosure include a light detection and ranging (LIDAR) sensor system that 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 and the second local oscillator signal to a first LIDAR pixel among the plurality of LIDAR pixels.

[0004] In one embodiment, 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 one embodiment, the one or more processors are further configured to drive the first local oscillator module to provide the first local oscillator signal and the second local oscillator signal to a second LIDAR pixel among the plurality of LIDAR pixels and to 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 one embodiment, the transmit beam module is configured to provide the transmit beam to a specific LIDAR pixel among the plurality of LIDAR pixels.

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

[0008] In one embodiment, among a plurality of LIDAR pixels, at least a first LIDAR pixel and a second LIDAR pixel include (1) a transmission optical antenna that emits a transmission beam, (2) a reception optical antenna that detects a return beam, (3) a first receiver configured to receive (i) a first polarization direction of the return beam and (ii) a first local oscillator signal from a local oscillator module, and (4) a second receiver configured to receive (i) a second polarization direction of the return beam and (ii) a second local oscillator signal from the local oscillator module.

[0009] In one embodiment, the reception optical antenna includes a first polarization reception grating configured to direct a first polarization direction of the return beam to the first receiver and a second polarization reception grating configured to direct a second polarization direction of the return beam to the second receiver. The first polarization reception grating is arranged at a distance from the second polarization reception grating.

[0010] In one embodiment, the first receiver includes a first optical mixer, and the second receiver includes a second optical mixer.

[0011] In one embodiment, the local oscillator module is configured to provide the first local oscillator signal and the second local oscillator signal only to one specific LIDAR pixel among a plurality of LIDAR pixels at any given time.

[0012] In one embodiment, the LIDAR sensor system further includes a light source configured to emit near-infrared light and a splitter configured to split the near-infrared light into a transmission 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 one embodiment, the local oscillator module includes at least two optical switches.

[0014] In one embodiment, the first local oscillator signal has a first polarization direction, and the second local oscillator signal has a second polarization direction different from the first polarization direction.

[0015] In one embodiment, the first polarization direction is orthogonal to the second polarization direction.

[0016] Embodiments of the present disclosure include a light detection and ranging (LIDAR) device and an autonomous vehicle control system for an autonomous vehicle including one or more processors. The one or more processors are configured to control the autonomous vehicle in response to the beat signal. The LIDAR device includes a plurality of LIDAR pixels configured to generate a beat signal 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 among the plurality of LIDAR pixels.

[0017] In one embodiment, 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 (i) drive the transmit beam module to provide a 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.

[0018] In one embodiment, one or more processors drive a local oscillator module to provide a first local oscillator signal and a second local oscillator signal to a second LIDAR pixel among a plurality of LIDAR pixels, and 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, the transmission beam module is further configured to drive a transmission beam to provide the transmission beam to the second LIDAR pixel.

[0019] In one embodiment, the transmission beam module is configured to provide a transmission beam to a specific LIDAR pixel among a plurality of LIDAR pixels.

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

[0021] Embodiments of the present disclosure include an autonomous vehicle including an optical detection and ranging (LIDAR) device and one or more processors configured to control the autonomous vehicle in response to a beat signal. The LIDAR device includes a plurality of LIDAR pixels configured to generate a beat signal 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 for receiving a first local oscillator signal and a second local oscillator input for receiving 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 among the plurality of LIDAR pixels.

[0022] Embodiments of the present 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 transmission beam and a local oscillator signal. The LIDAR sensor system includes a polarization module configured to receive the local oscillator signal and generate a first local oscillator signal and a second local oscillator signal different from the first local oscillator signal. The LIDAR sensor system includes a plurality of LIDAR pixels. The LIDAR sensor system includes a transmission 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 a transmission beam, a first local oscillator signal, and a second local oscillator signal to a specific LIDAR pixel among the plurality of LIDAR pixels to sequentially scan the plurality of LIDAR pixels one by one at a time. The LIDAR sensor system includes a power monitor coupled to the first LIDAR pixel, the power monitor being configured to detect the amount of power in the transmission beam provided to the first LIDAR pixel.

[0023] In one embodiment, while 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, the one or more processors are configured to drive the transmission beam module to provide a transmission beam to the first LIDAR pixel.

[0024] In one embodiment, the first LIDAR pixel includes a first optical antenna configured to emit a transmission beam, a second optical antenna configured to detect a return beam, a first receiver configured to receive (i) a first polarization direction of the return beam and (ii) a first local oscillator signal from a local oscillator module, and a second receiver configured to receive (i) a second polarization direction of the return beam and (ii) a second local oscillator signal from the local oscillator module.

[0025] In one embodiment, the second optical antenna includes a Dual-Polarization Receive Grating configured to (i) direct the first polarization direction of the return beam to the first receiver and (ii) direct the second polarization direction of the return beam to the second receiver.

[0026] In one embodiment, the second optical antenna includes a first polarization receive grating configured to direct the first polarization direction of the return beam to the first receiver. The second optical antenna includes a second polarization receive grating configured to direct the second polarization direction of the return beam to the second receiver. The first polarization receive grating is arranged at a distance from the second polarization receive grating.

[0027] In one embodiment, the first receiver includes a first optical mixer. The second receiver includes a second optical mixer.

[0028] In one embodiment, the local oscillator module is configured to provide the first local oscillator signal and the second local oscillator signal to only one specific LIDAR pixel among a plurality of LIDAR pixels at any given time.

[0029] In one embodiment, the local oscillator module includes a plurality of optical switches arranged in a multilayer configuration.

[0030] In one embodiment, the first local oscillator signal has a first polarization direction. The second local oscillator signal has a second polarization direction different from the first polarization direction.

[0031] In one embodiment, the first polarization direction is orthogonal to the second polarization direction.

[0032] Embodiments of the present disclosure include an autonomous vehicle control system for an autonomous vehicle. The autonomous vehicle control system includes a Light Detection and Ranging (LIDAR) 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 transmission beam and a local oscillator signal. The LIDAR system includes a polarization module configured to receive the local oscillator signal and generate a first local oscillator signal and a second local oscillator signal different from the first local oscillator signal. The LIDAR system includes a plurality of LIDAR pixels. The LIDAR system includes a transmission 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 transmission beam, the first local oscillator signal, and the second local oscillator signal to a specific LIDAR pixel among the plurality of LIDAR pixels to sequentially scan the plurality of LIDAR pixels one by one at a time. The LIDAR sensor system includes a power monitor coupled to the first LIDAR pixel, and the power monitor is configured to detect the amount of power in the transmission beam provided to the first LIDAR pixel.

[0033] In one embodiment, while 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, the one or more processors are configured to drive the transmission beam module to provide the transmission beam to the first LIDAR pixel.

[0034] Embodiments of the present disclosure include autonomous vehicles. 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 transmission beam and a local oscillator signal. The LIDAR system includes a polarization module configured to receive the local oscillator signal and generate a first local oscillator signal and a second local oscillator signal different from the first local oscillator signal. The LIDAR system includes a plurality of LIDAR pixels. The LIDAR system includes a transmission 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 a transmission beam, the first local oscillator signal, and the second local oscillator signal to a specific LIDAR pixel among the plurality of LIDAR pixels to sequentially scan the plurality of LIDAR pixels one by one at a time. The LIDAR system includes a power monitor coupled to the first LIDAR pixel, and the power monitor is configured to detect the amount of power in the transmission beam provided to the first LIDAR pixel.

[0035] In one embodiment, the power monitor includes a detector.

[0036] In one embodiment, the detector includes a photodiode.

[0037] In one embodiment, at least one of the local oscillator module or the transmission beam module includes a plurality of optical switches in a multilayer configuration.

[0038] In one embodiment, the local oscillator module includes a first plurality of optical switches arranged in a first multilayer configuration, and the transmission beam module includes a second plurality of optical switches arranged in a second multilayer configuration different from the first multilayer configuration.

[0039] In one embodiment, the first multilayer configuration includes more switches than the second multilayer configuration.

[0040] In one embodiment, a LIDAR sensor system includes a first waveguide coupled between a polarization module and a first local oscillator input of a local oscillator module, and a second waveguide coupled between the polarization module and a second local oscillator input of the local oscillator module.

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

[0042] Embodiments of the present disclosure include an optical 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 transmission 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 transmission beam, the switching device being disposed in a multilayer configuration and including a plurality of optical switches operable to sequentially transmit the optical beam to the plurality of emitters.

[0043] In one embodiment, the multilayer configuration includes a first layer including a first group of the plurality of optical switches. The multilayer configuration includes a second layer including a second group of the plurality of optical switches, the second group including more optical switches than the first group. The multilayer configuration includes a third layer including a third group of the plurality of optical switches, the third group including more optical switches than the second group.

[0044] In one embodiment, the first group includes one optical switch, the second group includes two optical switches, and the third group includes four optical switches.

[0045] In one embodiment, the switching device further includes an optical device that couples one optical switch of the second group to two optical switches of the third group.

[0046] In one embodiment, the optical device includes a waveguide crossing.

[0047] In one embodiment, the plurality of optical switches are independently controlled.

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

[0049] In one embodiment, among the plurality of emitters, the transmission beam emitted by the first emitter is reflected from the object as a return beam and received by the first emitter.

[0050] In one embodiment, the first emitter includes a transmission circuit configured to transmit a transmission beam and a reception circuit configured to receive a return beam.

[0051] In one embodiment, the light source includes a laser.

[0052] In one embodiment, the LIDAR sensor includes a local oscillator configured to receive a local oscillator signal. The local oscillator is arranged in a multilayer configuration and includes a plurality of optical switches operable to sequentially transmit the local oscillator signal to a plurality of emitters.

[0053] In one embodiment, 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. The first local oscillator signal has a first polarization direction, and the second local oscillator signal has a second polarization direction different from the first polarization direction.

[0054] In one embodiment, the second polarization direction is orthogonal to the first polarization direction.

[0055] In one embodiment, the LIDAR sensor includes a first interface that optically couples a switching device to a plurality of emitters, and a second interface that optically couples a local oscillator to the plurality of emitters.

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

[0057] In one embodiment, the second optical antenna includes a dual-polarization optical antenna configured to detect the first polarization direction of the return beam and the second polarization direction of the return beam.

[0058] In one embodiment, at least the first emitter of the plurality of emitters includes a first coherent receiver configured to generate a first signal in response to receiving a first local oscillator signal and the first polarization direction of the return beam, and a second coherent receiver configured to generate a second signal in response to receiving a second local oscillator signal and the second polarization direction of the return beam.

[0059] In one embodiment, the LIDAR sensor includes a plurality of power monitors configured to monitor the power levels of the transmission beams emitted by respective ones of the plurality of emitters.

[0060] Embodiments of the present 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 transmission 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 transmission beam, the switching device being arranged in a multilayer configuration and including a plurality of optical switches operable to sequentially transmit the transmission beam to the plurality of emitters.

[0061] Embodiments of the present 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 transmission 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 transmission beam, the switching device being arranged in a multilayer configuration and including a plurality of optical switches operable to sequentially transmit the transmission beam to the plurality of emitters.

[0062] Embodiments of the present disclosure include a light detection and ranging (LIDAR) sensor. The LIDAR sensor includes a light source configured to emit light. The LIDAR sensor includes a plurality of LIDAR pixels each including (i) a first optical antenna configured to transmit a light beam into the surrounding environment and (ii) a second optical antenna configured to detect a return beam representing the light beam reflected from an object in the surrounding environment. The LIDAR sensor includes a switching device including a plurality of optical switches arranged in a multi-layer configuration, the plurality of optical switches being operable to sequentially transmit the light beam to respective ones of the plurality of LIDAR pixels for transmitting 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 transmit the one or more local oscillator signals to respective LIDAR pixels.

[0063] In one embodiment, the multi-layer configuration includes a first layer including a first group of the plurality of optical switches, a second layer including a second group of the plurality of optical switches, the second group including more optical switches than the first group, and a third layer including a third group of the plurality of optical switches, the third group including more optical switches than the second group.

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

[0065] In one embodiment, the switching device further includes an optical device coupling one optical switch of the second group to two optical switches of the third group.

[0066] In one embodiment, the optical device includes a waveguide intersection.

[0067] In one embodiment, the plurality of optical switches are independently controlled.

[0068] In one embodiment, the plurality of optical switches can operate to transmit optical beams to a plurality of LIDAR pixels one by one at a time.

[0069] In one embodiment, 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 different from the first polarization.

[0070] In one embodiment, 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 one embodiment, the second polarization is orthogonal to the first polarization.

[0072] In one embodiment, the second optical antenna includes a dual-polarization optical antenna configured to detect the first polarization direction and the second polarization direction of the return beam.

[0073] In one embodiment, the light source includes a laser, and the optical beam includes a laser beam.

[0074] In one embodiment, the LIDAR sensor includes a power monitor configured to monitor the amount of power included in the optical beam transmitted to each LIDAR pixel.

[0075] In one embodiment, the LIDAR sensor includes one or more processors configured to (i) drive a switching device to transmit an optical beam to each of the plurality of LIDAR pixels and (ii) drive a local oscillator module to transmit one or more local oscillator signals to each of the LIDAR pixels.

[0076] In one embodiment, while one or more processors are configured to drive a switching device to transmit an optical beam to respective LIDAR pixels, the one or more processors are configured to drive a local oscillator module to transmit one or more local oscillator signals to respective LIDAR pixels.

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

[0078] In one embodiment, the plurality of LIDAR pixels further includes receivers configured to convert a return beam received by respective second optical antennas into an electrical signal.

[0079] In one embodiment, the receivers include one or more photodiodes.

[0080] Embodiments of the present 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 an optical beam. The LIDAR system includes a plurality of LIDAR pixels including (i) a first optical antenna configured to transmit the optical beam to the surrounding environment and (ii) a second optical antenna configured to detect a return optical beam representing the optical beam reflected from an object in the surrounding environment. The LIDAR system includes a switching device including a plurality of optical switches arranged in a multilayer configuration, the plurality of optical switches including optical switches operable to selectively transmit the optical beam to respective ones of the plurality of LIDAR pixels for transmitting the optical beam to the surrounding environment. The LIDAR system includes a local oscillator module configured to receive one or more local oscillator signals and transmit the one or more local oscillator signals to respective LIDAR pixels.

[0081] Embodiments of the present disclosure include autonomous vehicles. 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, each including (i) a first optical antenna configured to transmit the light beam into the surrounding environment and (ii) a second optical antenna configured to detect a return light beam representing the light beam reflected from an object in the surrounding environment. The LIDAR system includes a switching device including a plurality of optical switches arranged in a multi-layer configuration, the plurality of optical switches including optical switches operable to selectively transmit the light beam to respective LIDAR pixels among the plurality of LIDAR pixels for transmitting 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 transmit the one or more local oscillator signals to respective LIDAR pixels.

[0082] Embodiments of the present 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. At least one of the one or more LIDAR pixels includes a transmitting optical antenna, a receiving optical antenna, and at least one receiver. The transmitting optical antenna is configured to emit a transmitting beam. The receiving optical antenna is configured to detect (i) a first polarization direction of the return beam and (ii) a second polarization direction 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 the distance to an object.

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

[0084] In one embodiment, the first local oscillator signal has a first polarization direction, and the second local oscillator signal has a second polarization direction.

[0085] In one embodiment, at least one signal includes a first signal and a second signal. The first receiver is configured to generate a first signal representing a return beam in the first polarization direction, and the second receiver is configured to generate a second signal representing a return beam in the second polarization direction.

[0086] In one embodiment, 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] In one embodiment, the receiving optical antenna includes a first single-polarization grating coupler and a second single-polarization grating coupler. The first single-polarization grating coupler is configured to couple the first polarization direction of the return beam to at least one receiver. The second single-polarization grating coupler is configured to couple the second polarization direction of the return beam to at least one receiver.

[0088] In one embodiment, the transmitting optical antenna includes a third single-polarization grating coupler configured to emit a transmission beam in the first polarization direction. 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 one embodiment, the first single-polarization grating coupler can be orthogonal to or rotated by about 90 degrees with respect to the second single-polarization grating coupler.

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

[0091] In one embodiment, the local oscillator network is configured to provide at least two of the plurality of local oscillator signals to each of the plurality of LIDAR pixels.

[0092] In one embodiment, the LIDAR device further includes at least one passive splitter configured to combine the transmission signal to at least two of the one or more LIDAR pixels.

[0093] In one embodiment, the LIDAR 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 configured to generate an electrical output signal representative of the power level of the transmission signal.

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

[0095] In one embodiment, the transmit optical antenna is disposed in a first semiconductor layer, and the receive optical antenna is disposed in a second semiconductor layer stacked under the first semiconductor layer.

[0096] In one embodiment, the first semiconductor layer includes an element of Group III or Group V, and the second semiconductor layer is a nitride layer.

[0097] In one embodiment, the first polarization direction is orthogonal to the second polarization direction.

[0098] Embodiments of the present disclosure include an autonomous vehicle control system for an autonomous vehicle. The autonomous vehicle control system includes a light detection and ranging (LIDAR) device. 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. 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 direction of the return beam and (ii) a second polarization direction 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 the distance to an object.

[0099] In one embodiment, the receive optical antenna includes a first single-polarization grating coupler and a second single-polarization grating coupler. The first single-polarization grating coupler is configured to couple the first polarization direction of the return beam to at least one receiver, and the second single-polarization grating coupler is configured to couple the second polarization direction of the return beam to at least one receiver.

[0100] In one embodiment, the transmit optical antenna is disposed in a first semiconductor layer, and the receive optical antenna is disposed in a second semiconductor layer stacked under the first semiconductor layer.

[0101] Embodiments of the present disclosure include autonomous vehicles. 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. 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 direction of the return beam and (ii) a second polarization direction 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 the distance to an object.

[0102] Embodiments of the present disclosure include a vehicle 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 transmission beam and a local oscillator signal. The LIDAR sensor system includes a polarization module configured to receive the local oscillator signal and generate a first local oscillator signal and a second local oscillator signal different from the first local oscillator signal. The LIDAR sensor system includes a plurality of LIDAR pixels. The LIDAR sensor system includes a transmission beam module configured to provide the transmission beam to only one 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 transmission beam module to provide the transmission beam to a first LIDAR pixel among 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 the amount of power of the transmission beam provided to the first LIDAR pixel.

[0103] In one embodiment, while 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, the one or more processors are configured to drive the transmission beam module to provide the transmission beam to the first LIDAR pixel.

[0104] In one embodiment, the first LIDAR pixel includes a first optical antenna configured to emit a transmission beam, a second optical antenna configured to detect a return beam, a first receiver configured to receive (i) a first polarization direction of the return beam and (ii) a first local oscillator signal from a local oscillator module, and a second receiver configured to receive (i) a second polarization direction of the return beam and (ii) a second local oscillator signal from the local oscillator module.

[0105] In one embodiment, the second optical antenna includes a dual-polarization receiving grating that (i) directs the first polarization direction of the return beam to the first receiver and (ii) directs the second polarization direction of the return beam to the second receiver.

[0106] In one embodiment, the second optical antenna includes a first polarization receiving grating configured to direct the first polarization direction of the return beam to the first receiver and a second polarization receiving grating configured to direct the second polarization direction of the return beam to the second receiver. The first polarization receiving grating is spaced apart from the second polarization receiving grating.

[0107] In one embodiment, the first receiver includes a first optical mixer, and the second receiver includes a second optical mixer.

[0108] In one embodiment, the local oscillator module is configured to provide the first local oscillator signal and the second local oscillator signal to only one specific LIDAR pixel among a plurality of LIDAR pixels at any given time.

[0109] In one embodiment, the first local oscillator signal has a first polarization direction. The second local oscillator signal has a second polarization direction different from the first polarization direction.

[0110] In one embodiment, the first polarization direction is orthogonal to the second polarization direction.

[0111] In one embodiment, at least one of the local oscillator module or the transmission beam module includes a plurality of optical switches in a multilayer configuration.

[0112] In one embodiment, the local oscillator module includes a first plurality of optical switches arranged in a first multilayer configuration. The transmission beam module includes a second plurality of optical switches arranged in a second multilayer configuration different from the first multilayer configuration.

[0113] In one embodiment, the first multilayer configuration includes more switches than the second multilayer configuration.

[0114] In one embodiment, the power monitor includes a detector. The power monitor further includes a first waveguide through which the transmission beam passes and a second waveguide configured to receive a part of the transmission beam from the first waveguide. The detector is configured to convert a part of the transmission beam into an electrical signal to support power monitoring.

[0115] Embodiments of the present disclosure include an autonomous vehicle control system for an autonomous vehicle. The autonomous vehicle control system includes any of the optical detection and ranging (LIDAR) systems described above.

[0116] Embodiments of the present disclosure include an autonomous vehicle including any of the optical detection and ranging (LIDAR) systems described above.

Brief Description of the Drawings

[0117] Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following drawings, where the same reference numerals refer to the same parts in various drawings unless otherwise specified.

[0118]

Figure 1a

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Figure 1b

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Figure 1c

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Figure 1d

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Figure 2

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Figure 3

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Figure 4

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Figure 5

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Figure 6

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Figure 7

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Figure 8

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Figure 9

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Figure 10a

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Figure 10b

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Figure 11

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Figure 12a

Figure 12b

[0134] In this specification, the implementation of optical detection and ranging (LIDAR) with a switchable local oscillator signal will be described. In the following description, numerous specific details are presented in order to provide a thorough understanding of the embodiments. However, those skilled in the relevant art will recognize that the techniques described herein can be practiced without one or more of the specific details, or using other methods, components, materials, etc. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring certain aspects.

[0135] References to "one embodiment" or "an embodiment" throughout this specification mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Also, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

[0136] Throughout this specification, several technical terms are used. These terms have their ordinary meanings in the technical field from which they are derived, unless specifically defined herein or the context of use clearly has a different meaning. For the purposes of this disclosure, the term "Autonomous Vehicle" includes vehicles equipped with autonomous functions having any level of autonomy of the SAE International Standard J3016.

[0137] In some aspects of the present disclosure, visible light can be defined as having a wavelength range of about 380 nm to 700 nm. Non-visible light can be defined as light having wavelengths outside the range of visible light, such as ultraviolet and infrared light. Infrared light with a wavelength range of about 700 nm to 1 mm includes near-infrared light. In some aspects of the present disclosure, near-infrared light can be defined as having a wavelength range of about 700 nm to 1600 nm.

[0138] Frequency-modulated continuous-wave (FMCW) LIDAR transmits a frequency-modulated light beam to an object / target and directly measures the distance and speed of the object / target. The light reflected from the object / target can be combined with a tapped version of the light beam. The frequency of the resulting beat signal is proportional to the distance from the LIDAR system to the object after being corrected for the Doppler shift that requires a second measurement. Two measurements, which may or may not be performed simultaneously, provide both distance and velocity information.

[0139] Embodiments of the present disclosure include LIDAR systems and devices that use switchable local oscillator signals. The LIDAR device may include a plurality of LIDAR pixels. The LIDAR pixel may include 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 reflected from a target in the environment. The LIDAR pixel may have a plurality of optical receivers that receive different local oscillator signals. For example, a first optical receiver of the LIDAR pixel may receive a first local oscillator signal having a first polarization direction, and a second optical receiver of the LIDAR pixel may receive a second local oscillator signal having a second polarization direction different from the first polarization direction. The first optical receiver may receive a first polarization direction of the return signal, and the second optical receiver may receive a second polarization direction of the return signal. Previously, the first local oscillator signal and the second local oscillator signal may have been provided to each LIDAR pixel simultaneously. However, this technique may consume optical power and generate optical noise, which may reduce the signal-to-noise ratio (SNR) when detecting the return beam.

[0140] In embodiments of the present disclosure, the 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 among a plurality of LIDAR pixels. When the first local oscillator signal and the second local oscillator signal are provided to the beam-emitting LIDAR pixel, a transmission beam (e.g., infrared laser light) can be provided to the beam-emitting LIDAR pixel at the same time. The transmission beam module can be configured to provide a transmission beam to any beam-emitting LIDAR pixel among a plurality of LIDAR pixels. In this way, the transmission beam and the first local oscillator signal and the second local oscillator signal can be selectively (simultaneously in some embodiments) provided to one LIDAR pixel at a time to scan a plurality of LIDAR pixels. A beam-emitting LIDAR pixel is a LIDAR pixel that receives a transmission beam, a first local oscillator signal, and a second local oscillator signal at a given time.

[0141] Each LIDAR pixel within a plurality of LIDAR pixels may include a transmission optical antenna, a reception optical antenna, a first receiver, and a second receiver. The transmission optical antenna is configured to emit a transmission beam. The reception optical antenna is configured to detect a return beam. The first receiver may be configured to receive a first polarization direction of the return beam and a first local oscillator signal from the local oscillator module. The second receiver may be configured to receive a second polarization direction of the return beam and a second local oscillator signal from the local oscillator module. The first local oscillator signal may have a polarization direction 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 can be used to generate a LIDAR image of the environment. Such embodiments and other embodiments 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 showing an example of a system environment for an autonomous vehicle according to some embodiments.

[0144] Referring to FIG. 1a, an exemplary autonomous vehicle 110A in which various techniques disclosed herein can be implemented is shown. For example, vehicle 110A may include a power train 192 including a prime mover 194 that can be driven by an energy source 196 and supply power to a drive train 198, and a control system 180 including a direction control 182, a power train control 184, and a brake control 186. Vehicle 110A can transport people and / or cargo and can be implemented as any of a variety of types of vehicles including vehicles that can travel in various environments, and it will be understood that the foregoing components 180-198 can vary widely depending on the type of vehicle in which these components are used.

[0145] For simplicity, the embodiments discussed below focus on wheeled land vehicles such as automobiles, vans, trucks, buses, etc. In these embodiments, prime mover 194 may include one or more electric motors and / or internal combustion engines (among other things). The energy source may include, for example, a fuel system (e.g., providing gasoline, diesel, hydrogen, etc.), a battery system, a solar panel or other renewable energy source, and / or a fuel cell system. Drive train 198 includes a transmission and / or any other mechanical drive components for converting the output of prime mover 194 into vehicle motion, and wheels and / or tires, one or more brakes configured to controllably stop or decelerate vehicle 110A, and a direction or steering component (e.g., a rack and pinion steering linkage that generally pivots one or more wheels of vehicle 110A about a vertical axis to change the angle of the rotational plane of the wheel relative to the longitudinal axis of the vehicle) suitable for controlling the trajectory of vehicle 110A. In some embodiments, a combination of a power train and an energy source can be used (e.g., in the case of an electric / gas hybrid vehicle), and in some examples, multiple electric motors (e.g., dedicated to individual wheels or axles) can be used as prime movers.

[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 so that the vehicle 110A follows a desired trajectory. The power train control 184 may be configured to control the output of the power train 192, for example, to control the output of the prime mover 194, to control the gears of the transmission in the drive train 198, thereby enabling control of the speed and / or direction of the vehicle 110A. The brake control 186 may be configured to control one or more brakes that decelerate or stop the vehicle 110A, such as 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 vehicles or track-type vehicles, construction equipment, etc., can necessarily use different power trains, drive trains, energy sources, direction controls, power train controls and brake controls. Further, in some embodiments, some components may be combined, for example, when the direction control of the vehicle is mainly processed by changing the output of one or more prime movers. Therefore, the embodiments disclosed herein are not limited to specific applications in the autonomous land vehicles of the technology disclosed herein.

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

[0149] Sensor 130 may include various sensors suitable for collecting information from the vehicle's surrounding environment for use in controlling the operation of the vehicle. For example, sensor 130 may include a radar sensor 134, a LIDAR (Light Detection and Ranging) sensor 136, a 3D positioning sensor 138, such as an accelerometer, a gyroscope, a magnetometer, or any sensor of 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 sensor 138 can be used to determine the position of the vehicle on the earth using satellite signals. Sensor 130 may include a camera 140 and / or an Inertial Measurement Unit (IMU) 142. The camera 140 can be a monographic or stereographic camera and can record still images and / or videos. The IMU 142 may include a plurality of gyroscopes and accelerometers capable of detecting the linear and rotational motion of the vehicle in three directions. One or more encoders (not shown), such as wheel encoders, can be used to monitor the rotation of one or more wheels of the vehicle 110A. Each sensor 130 can output sensor data at various data rates, which may be different from the data rates of other sensors 130.

[0150] The output of sensor 130 can be provided to a set of control subsystems 150 including a position estimation subsystem 152, a perception subsystem 154, a planning subsystem 156, and a control subsystem 158. The position estimation subsystem 152 can perform functions such as precisely determining the position and orientation (also referred to as "pose") of vehicle 110A within the surrounding environment and generally within a partially referenced frame. The position of the autonomous vehicle can be compared to the positions of additional vehicles in the same environment as part of labeled autonomous vehicle data generation. The perception subsystem 154 can perform functions such as detecting, tracking, determining, and / or identifying objects within the environment surrounding vehicle 110A. Machine learning models can be used to track objects. The planning subsystem 156 can perform functions such as planning the trajectory of vehicle 110A within a given time frame given a desired destination, as well as stationary and moving objects within the environment. Machine learning can be used for vehicle trajectory planning. The control subsystem 158 can perform functions such as generating appropriate control signals for controlling various control devices of vehicle control system 120 to implement the planned trajectory of vehicle 110A. Machine learning models can be used to generate one or more signals for controlling the autonomous vehicle to implement the planned trajectory.

[0151] It will be appreciated that the collection of components shown in FIG. 1a for vehicle control system 120 is merely exemplary. In some embodiments, individual sensors may be omitted. Additionally or alternatively, in some embodiments, multiple sensors of the type shown in FIG. 1a can be used to cover redundancy and / or various regions around the vehicle, and other types of sensors can be used. Similarly, various types and / or combinations of control subsystems can be used in other embodiments. Also, although subsystems 152-158 are shown as being separate from processor 122 and memory 124, in some embodiments, some or all of subsystems 152-158 can reside in one or more memories 124 and be implemented with program code instructions 126 performed by one or more processors 122, and it will be appreciated that these subsystems 152-158 can, in some cases, be implemented using the same processor and / or memory. Subsystems can be implemented using at least in part various dedicated circuit logics, various processors, various field programmable gate arrays (FPGAs), various application specific integrated circuits (ASICs), various real-time controllers, etc., and as described above, many subsystems can use circuits, processors, sensors, and / or other components. Also, the various components of vehicle control system 120 can be networked in various ways.

[0152] In some embodiments, vehicle 110A can include an auxiliary vehicle control system (not shown) that can be used as a redundant or backup control system for vehicle 110A. The auxiliary vehicle control system can fully operate autonomous vehicle 110A if an adverse event occurs in vehicle control system 120, but in other embodiments, the auxiliary vehicle control system can have only limited functionality, such as performing a controlled stop of vehicle 110A in response to an adverse event detected by vehicle control system 120. In other embodiments, the auxiliary vehicle control system may be omitted.

[0153] Generally, various architectures including various combinations of software, hardware, circuit logic, sensors, and networks can be used to implement the various components shown in FIG. 1. For example, each processor can be implemented as a microprocessor, and each memory can include not only random access memory (RAM) devices that make up the main memory, but also any auxiliary level of memory, such as cache memory, non-volatile or backup memory (e.g., programmable or flash memory), read-only memory, etc. Also, each memory can be considered to include not only a memory storage device physically located elsewhere in vehicle 110A, such as any cache memory within the processor, but also any storage capacity used as virtual memory (e.g., stored in a mass storage device or in another computer controller). One or more processors shown in FIG. 1a, or completely separate processors, can be used to implement additional functions other than for autonomous control purposes, such as controlling an entertainment system, operating doors, lighting, convenience functions, etc. in vehicle 110A.

[0154] Also, for additional storage, vehicle 110A can include one or more mass storage devices, such as removable disk drives, hard disk drives, direct access storage devices (DASD), optical drives (e.g., CD drives, DVD drives, etc.), solid state storage drives (SSD), network attached storage, storage area networks, and / or tape drives, etc.

[0155] Also, vehicle 110A includes a user interface 164 so that vehicle 110A can receive a number of inputs from a user or operator and generate outputs such as one or more displays, touchscreens, audio and / or gesture interfaces, buttons, and other tactile controls. Otherwise, user input can be received via other computers or electronic devices, such as an app on a mobile device or a web interface.

[0156] Further, vehicle 110A may include one or more network interfaces, such as network interface 162, which allows vehicle 110A to communicate with other computers and electronic devices, including central services such as cloud services, to receive environment and other data for use in autonomous control, and to communicate with one or more networks (e.g., local area network (LAN), wide area network (WAN), wireless network, and / or the Internet). Data collected by one or more sensors 130 may be uploaded via network 170 to computing system 172 for additional processing. A timestamp may be added to each instance of vehicle data prior to upload.

[0157] Each processor shown in FIG. 1a, and the various additional controllers and subsystems disclosed herein, generally operate under the control of an operating system and perform or depend on various computer software applications, components, programs, objects, modules, data structures, etc., as will be described in detail below. Also, various applications, components, programs, objects, modules, etc. may be performed by one or more processors of other computers coupled to vehicle 110A via network 170, e.g., the processing required to implement the functionality of a computer program may be allocated via the network to multiple computers and / or services in a distributed, cloud-based, or client-server computing environment.

[0158] Generally, routines performed to implement the various embodiments described herein may be embodied as part of an operating system or as a specific application, component, program, object, module, or sequence of instructions, or as a subset thereof, and are referred to herein as "program code." The program code may reside at various times in various memories and storage devices and may include one or more instructions that, when read and executed by one or more processors, perform the steps necessary to execute the steps or elements that implement the various aspects of the present disclosure. Also, the embodiments are described in the context of fully functional computers and systems, and the various embodiments described herein can be distributed as various forms of program products, and it should be understood that such embodiments can be implemented regardless of the specific type of computer-readable medium used to actually perform 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-ROM, DVD, etc.).

[0160] Also, the various program codes described below can be identified based on the applications implemented in specific embodiments. However, any specific program nomenclature below is used merely for convenience, and thus, it should be understood that the present disclosure should not be limited to use only in any specific application identified and / or implied by such nomenclature. Further, the manner in which a computer program can be composed of routines, procedures, methods, modules, objects, etc. is generally endless, and when considering the various ways in which program functions are allocated among various software layers (e.g., operating systems, libraries, APIs, applications, applets, etc.) resident in a general computer, it should be understood that the present disclosure is not limited to the specific structure and allocation of the program functions described herein.

[0161] The environment shown in FIG. 1a is not intended to limit the embodiments disclosed herein. In fact, other alternative hardware and / or software environments can be used without departing from the scope of the embodiments disclosed herein.

[0162] 2. FM LIDAR for Automotive Applications

[0163] The truck may include a LIDAR system (e.g., the vehicle control system 120 of FIG. 1a, the LIDAR system 200 of FIG. 2, etc.). In some embodiments, the LIDAR system can encode an optical signal using frequency modulation and scatter the encoded optical signal into free space using optics. By detecting the frequency difference between the encoded optical signal and the return signal reflected from an object, a frequency modulation (FM) LIDAR system can use the Doppler effect to determine the position of the object and / or accurately measure the speed of the object. The FM LIDAR system can use continuous wave (referred to as "FMCW LIDAR" or "coherent FMCW LIDAR") or quasi-continuous wave (referred to as "FMQW LIDAR"). The LIDAR system can encode an optical signal using phase modulation (PM) and scatter the encoded optical signal into free space using optics.

[0164] FM or phase modulation (PM) LIDAR systems can offer significant advantages compared to conventional LIDAR systems for automotive and / or commercial truck transportation applications. First, in some cases, an object (e.g., a pedestrian wearing dark clothing) may have a low reflectivity in that only a small amount of the light hitting the object (e.g., 10% or less) is reflected back to the sensor of the FM or PM LIDAR system (e.g., sensor 130 of FIG. 1a). In other cases, an object (e.g., a shiny road sign) may have a high reflectivity (e.g., 10% or more) in that a large amount of the light hitting the object is reflected back to the sensor of the FM LIDAR system.

[0165] Regardless of the reflectivity of the object, the FM LIDAR system can detect (e.g., classify, recognize, discover, etc.) the object at a greater distance (e.g., twice as far) than a conventional LIDAR system. For example, the FM LIDAR system can detect low-reflectivity objects at 300 meters or more and high-reflectivity objects at 400 meters or more.

[0166] To achieve such an improvement in detection capabilities, an FM LIDAR system can use sensors (e.g., sensor 130 in FIG. 1a). In some embodiments, these sensors may be sensitive to single photons, which means that the sensors can detect the minimum amount of light possible. In some applications, the FM LIDAR system can use infrared wavelengths (e.g., 950 nm, 1550 nm, etc.), but is not limited to the range of infrared wavelengths (e.g., near-infrared: 800 nm to 1500 nm, mid-infrared: 1500 nm to 5600 nm, and far-infrared: 5600 nm to 1,000,000 nm). By operating the FM or PM LIDAR system at infrared wavelengths, the FM or PM LIDAR system can broadcast stronger light pulses or light beams while meeting eye safety standards. Conventional LIDAR systems are often not sensitive to single photons and / or operate only at near-infrared wavelengths, so it is necessary to limit the light output (and distance detection capabilities) for eye safety.

[0167] Therefore, by detecting objects at greater distances, the FM LIDAR system can secure more time to react to unexpected obstacles. In fact, in the case of large, fast-moving vehicles (e.g., commercial trucks), even a few extra milliseconds can improve safety and convenience.

[0168] Another advantage of the FM LIDAR system is that it instantaneously provides accurate speed for each data point. In some embodiments, the speed measurement is achieved using the Doppler effect that shifts the frequency of the light received from an object based on at least one of the speed in the radial direction (e.g., the direction vector between the detected object and the sensor) or the frequency of the laser signal. For example, for speeds occurring in road situations where the speed is less than 100 meters per second (m / s), this shift at a wavelength of 1550 nanometers (nm) corresponds to a frequency shift of less than 130 megahertz (MHz). This frequency shift is so small that it is difficult to directly detect in the optical domain. However, when using coherent detection in an FMCW, PMCW, or FMQW LIDAR system, the signal can be converted to the RF domain so that various signal processing techniques can be used to calculate the frequency shift. This allows the autonomous vehicle control system to process the received data more quickly.

[0169] Also, instantaneous speed calculation makes it easier for the FM LIDAR system to identify objects that are far away or have sparse data points and / or to track how these objects are moving over time. For example, an FM LIDAR sensor (e.g., sensor 130 in FIG. 1a) may receive only a few returns (e.g., hits) for an object that is 300 m away, but if these returns provide a speed value of interest (e.g., moving towards the vehicle at a speed of 70 mph or more), the FM LIDAR system and / or the autonomous vehicle control system can determine individual weights for the probabilities associated with the object.

[0170] The faster identification and / or tracking of the FM LIDAR system provides the autonomous vehicle control system with more time to maneuver the vehicle. Also, by more accurately understanding the moving speed of the object, the autonomous vehicle control system can plan more appropriate responses.

[0171] Another advantage of the FM LIDAR system is that it is less static compared to conventional LIDAR systems. That is, conventional LIDAR systems designed to be more sensitive to light generally experience a decrease in performance under bright sunlight. Also, these systems tend to suffer from crosstalk (e.g., when sensors are confused by each other's light pulses or light beams) and self-interference (e.g., when a sensor is confused by its own previous light pulses or light beams). To overcome this drawback, vehicles using conventional LIDAR systems often require additional hardware, complex software, and / or more computing power to manage this "noise".

[0172] On the other hand, the FM LIDAR system is specially designed so that each sensor responds only to its own optical characteristics (e.g., light beam, light wave, light pulse), and thus does not experience this kind of problem. If the returned light does not match the timing, frequency, and / or wavelength of the originally transmitted light, the FM sensor can filter (e.g., remove, ignore, etc.) the data point. This enables the FM LIDAR system to produce (e.g., generate, derive, etc.) more accurate data with fewer hardware or software requirements, enabling safer and smoother driving.

[0173] Finally, the FM LIDAR system is easier to expand than conventional LIDAR systems. As more autonomous vehicles (e.g., cars, commercial trucks, etc.) appear on the road, vehicles driven by the FM LIDAR system are likely to no longer have to face interference problems due to sensor crosstalk. Also, the FM LIDAR system uses less optical peak power than conventional LIDAR sensors. This allows some or all of the optical components of the FM LIDAR to be manufactured on a single chip, which provides unique advantages as described herein.

[0174] 3. Commercial Truck Transportation

[0175] Figure 1b is a block diagram showing an example of a system environment of an autonomous commercial truck vehicle according to some embodiments. Environment 100B includes a commercial truck 102B for carrying cargo 106B. In some embodiments, commercial truck 102B can include vehicles configured for long-haul cargo transportation, regional cargo transportation, intermodal cargo transportation (i.e., where a vehicle on a road infrastructure is used as one of several transportation modes for transporting cargo), and / or any other road infrastructure cargo transportation applications. Commercial truck 102B can be a flatbed truck, a refrigerated truck (e.g., a reefer truck), a vented van (e.g., a dry van), a moving truck, etc. Cargo 106B can be goods and / or agricultural products. Commercial truck 102B can include a trailer for carrying cargo 106B such as a flatbed trailer, a lowboy trailer, a step deck trailer, an expandable flatbed trailer, a side kit trailer, etc.

[0176] Environment 100B includes an object 110B (shown as another vehicle in FIG. 1b) within a distance range of 30 meters or less from the truck.

[0177] The commercial truck 102B may include a LIDAR system 104B (e.g., the FM LIDAR system of FIG. 1a, the vehicle control system 120, etc.) for determining the distance to the object 110B and measuring the speed of the object 110B. Although FIG. 1b shows one LIDAR system 104B mounted on the front of the commercial truck 102B, the number of LIDAR systems in the commercial truck and the mounting area of the LIDAR system are not limited to a specific number and a specific area. The commercial truck 102B may include any number of LIDAR systems 104B (or its components such as sensors, modulators, coherent signal generators, etc.) mounted in any area of the commercial truck 102B (e.g., the front, back, sides, top, bottom, underside, and / or bottom) to facilitate object detection in any free space for the commercial truck 102B.

[0178] As shown, the LIDAR system 104B in the environment 100B may be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) at a short distance (e.g., 30 meters or less) from the commercial truck 102B.

[0179] FIG. 1c is a block diagram showing an example of a system environment for an autonomous commercial truck vehicle according to some embodiments. The environment 100C includes the same components (e.g., the commercial truck 102B, the cargo 106B, the LIDAR system 104B, etc.) as those included in the environment 100B.

[0180] The environment 100C includes an object 110C (shown as another vehicle in FIG. 1c) within a distance range of (i) 30 meters or more and (ii) 150 meters or less from the commercial truck 102B. As shown, the LIDAR system 104B of the environment 100C may be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) at a certain distance (e.g., 100 meters) from the commercial truck 102B.

[0181] Figure 1d is a block diagram showing an example of a system environment for an autonomous commercial truck vehicle according to some embodiments. Environment 100D includes the same components (e.g., commercial truck 102B, cargo 106B, LIDAR system 104B, etc.) as those included in environment 100B.

[0182] Environment 100D includes an object 110D (shown as another vehicle in FIG. 1d) within a distance range of 150 meters or more from commercial truck 102B. As shown, the LIDAR system 104B of environment 100D can be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) at a long distance (e.g., 300 meters) from commercial truck 102B.

[0183] In the field of commercial truck transportation applications, as the weight of the vehicle increases and accordingly a longer stopping distance is required, it is important to effectively detect objects in all ranges. FM LIDAR systems (e.g., FMCW and / or FMQW systems) or PM LIDAR systems are optimal for commercial truck transportation applications due to the aforementioned advantages. Ultimately, commercial trucks equipped with these systems can improve the safety not only of the commercial trucks themselves but also of surrounding vehicles because of their improved ability to safely move people and goods over short or long distances. In various embodiments, these FM or PM LIDAR systems can be used in semi-autonomous application fields where a driver is on board the commercial truck and some functions of the commercial truck operate autonomously using the FM or PM LIDAR system, or in fully autonomous application fields where the commercial truck operates completely by the FM or LIDAR system alone or in combination with other vehicle systems.

[0184] 4. Continuous Wave Modulation and Quasi-Continuous Wave Modulation

[0185] In a LIDAR system using CW modulation, the modulator continuously modulates the laser light. For example, if the modulation period is 10 seconds, the input signal is modulated over the entire 10 seconds. Instead, in the case of a LIDAR system using quasi-CW modulation, the modulator modulates the laser light such that it has both an active portion and an inactive portion. For example, in the case of a 10-second period, the modulator modulates the laser light for only 8 seconds (also called the "active portion") and does not modulate the laser light for 2 seconds (also called the "inactive portion"). Thereby, since the modulator does not need to provide a continuous signal, the LIDAR system can reduce power consumption for 2 seconds.

[0186] In the case of frequency-modulated continuous-wave (FMCW) LIDAR for vehicle applications, although FMCW measurement and signal processing methodologies are used, it may be advantageous to operate the LIDAR system using quasi-CW modulation rather than having the optical signal always on (e.g., activated, powered, transmitted, etc.). In some embodiments, the quasi-CW modulation may have a duty cycle of 1% or more and up to 50% or less. If energy is consumed during the off state (e.g., deactivated, powered off, etc.) during the actual measurement time, the signal-to-noise ratio (SNR) can be improved or the requirements for signal processing can be reduced, so that all the energy can be consistently integrated over a longer period of time.

[0187] FIG. 2 shows a LIDAR system 200 including a local oscillator module 212 according to an embodiment of the present disclosure. The LIDAR system 200 can be an exemplary embodiment of the LIDAR system 104B (shown in FIG. 1b). In the embodiment shown in FIG. 2, the LIDAR system 200 further includes a laser 202, a splitter 204, a polarization module 206, a local oscillator module 212, a transmit beam module 220, a LIDAR pixel array 214, and processing logic 299. The splitter 204 can be coupled to the laser 202 to receive a transmit signal 210. The splitter 204 can split the transmit signal 210 into a transmit beam 213 and a local oscillator signal 211. Optionally, a polarization module, such as the polarization module 206, can receive the local oscillator signal 211 and generate a first local oscillator signal 224 and a second local oscillator signal 226. The first local oscillator signal 224 and the second local oscillator signal 226 can have different polarization directions. In the illustrated embodiment, the first local oscillator signal 224 and the second local oscillator signal 226 have orthogonal polarization directions, which is because the first local oscillator signal 224 is exemplified as S polarization (LOS) and the second local oscillator signal 226 is exemplified as P polarization (LOP). In an embodiment, the first local oscillator signal 224 and the second local oscillator signal 226 have the same polarization direction. At least one of the first local oscillator signal and the second local oscillator signal can be derived from the local oscillator signal 211.

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

[0189] In one embodiment, the LIDAR pixel array 214 includes eight LIDAR pixels, and at any given time, one of the LIDAR pixels of the LIDAR pixel array 214 is the beam-emitting LIDAR pixel. The beam-emitting LIDAR pixel may also receive a transmission beam via the optical bus 222. The processing logic 299 drives the local oscillator module 212 and the transmission beam module 220, and may provide the transmission beam 213, the first local oscillator signal 224, and the second local oscillator signal 226 to the same LIDAR pixel (beam-emitting LIDAR pixel) within the LIDAR pixel array 214. The processing logic 299 drives the local oscillator module 212 and the transmission beam module 220, and may provide the transmission beam 213, the first local oscillator signal 224, and the second local oscillator signal 226 to other LIDAR pixels within the LIDAR pixel array 214 in order to sequentially scan each LIDAR pixel as the beam-emitting LIDAR pixel. In this way, each LIDAR pixel can emit a transmission beam and detect a return beam as a reflection of the transmission beam reflected from a target in the environment. Each LIDAR pixel may detect the return beam and generate one or more beat signals, and the beat signals can be used to form a LIDAR image.

[0190] When the system 200 provides the transmission beam 213, the first local oscillator signal 224, and the second local oscillator signal 226 to the same LIDAR pixel (instead of providing them to all LIDAR pixels simultaneously), the optical power required to operate the LIDAR system 200 is reduced. Another potential advantage is that the optical noise of the LIDAR system 200 is reduced, and the signal-to-noise ratio (SNR) of the beat signal generated by the LIDAR pixel may be improved. For example, the reduction in optical noise caused by not providing all optical signals to each LIDAR pixel simultaneously results from a reduction in optical crosstalk between the waveguides of adjacent LIDAR pixels, which may help reduce the complexity of electrical signal routing. Reducing the complexity of electrical signal routing has the advantage of reducing the cost of conductors (e.g., copper), reducing the weight, and reducing the size of the LIDAR pixel array. In the case of autonomous vehicles, the LIDAR system can be placed on more vehicles at a lower cost, and the reduction in weight and size enables the placement of the LIDAR pixel array in more diverse positions on the autonomous vehicle.

[0191] FIG. 2 shows optical buses 216, 218, and 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 (LOS0 - 7) may include eight waveguides for providing a first local oscillator signal 224 to eight LIDAR pixels of LIDAR pixel array 214, and optical bus 218 (LOP0 - 7) may include eight waveguides for providing a second local oscillator signal 226 to eight LIDAR pixels of LIDAR pixel array 214. Similarly, optical bus 222 (TX0 - 7) may include eight waveguides for providing transmit beam 213 to eight LIDAR pixels of LIDAR pixel array 214. For 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 yet another example, LIDAR pixel array 214 may include 5, 25, or 125 LIDAR pixels. In these examples, various numbers of LIDAR pixels can be selected to achieve a preferred loss range.

[0192] FIG. 2 also shows buses 240 and 242. Buses 240 (RXS0 - 7) and 242 (RXP0 - 7) may be electrical buses rather than optical buses. Buses 240 and 242 can transmit beat signals generated by the LIDAR pixels of LIDAR pixel array 214.

[0193] FIG. 3 shows an exemplary diagram of a LIDAR transceiver 300 that may include some of the components of the LIDAR system 200 according to an embodiment of the present disclosure. According to one embodiment of the present disclosure, the LIDAR transceiver 300 includes a local oscillator module 302, which is coupled to provide a local oscillator signal to the LIDAR pixel array 304. The local oscillator module 302 may be configured identically or similarly to the local oscillator module 212.

[0194] The local oscillator (LO) module 302 is coupled to one or more of a plurality of input ports 306 via waveguides 310 and 312 and may receive one or both of the local oscillator signals LOS and LOP. According to an embodiment of the present disclosure, the local oscillator module 302 is configured to provide the local oscillator signals LOS and LOP to one or more LIDAR pixels of the LIDAR pixel array 304 such that the LIDAR pixels generate received signals RXS0-7 and RXP0-7 and provide signals to a plurality of output ports 308.

[0195] The LIDAR pixel array 304 may include a plurality of LIDAR pixels arranged along one or two dimensions of the footprint of the LIDAR transceiver 300. The LIDAR pixel array 304 may be configured identically or similarly to the LIDAR pixel array 214. According to one embodiment, the LIDAR pixel 314 may be an example of one or more of the LIDAR pixels of the LIDAR pixel array 304. According to one embodiment, the LIDAR pixel 314 may receive a transmit beam at port 316, receive a first local oscillator signal LOS at port 318, and receive a second local oscillator signal LOP at port 320. A transmit beam module 220 (not shown in FIG. 3) may selectively provide a transmit beam to port 316 via terminal TX7 of the LIDAR transceiver 300. According to an embodiment of the present disclosure, the LIDAR pixel 314 may be configured to generate a received signal RXS and / or a received signal RXP and provide one or both of the received signals RXS and RXP to port 322 and port 324, respectively.

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

[0197] The LIDAR transceiver 300 may include a power monitor array configured to detect the power levels in each of the transmission signals provided to the LIDAR pixels of the LIDAR pixel array 304. The power monitor array may include one power monitor for each LIDAR pixel of the LIDAR pixel array 304. The power monitor 332 may be an example of a power monitor of the power monitor array. The power monitor 332 may include a waveguide 334, a waveguide 336, and a photodiode 338. Since the transmission beam can propagate through the waveguide 334, the waveguide 334 may be disposed in-line with the transmission signal waveguide. The waveguide 336 may be located near the waveguide 334 to receive a portion of the transmission signal. The photodiode 338 may be coupled to the waveguide 336 and may be configured to convert a portion of the transmission signal into an electrical signal to support the power monitoring operation. The transceiver 300 may include a plurality of ports 340 communicatively coupled to the power monitors of the power monitor array and configured to provide a power monitor output external to the transceiver 300. In some embodiments, the ports 340 can be used to provide control signals from processing logic (e.g., processing logic 299) to drive the local oscillator module 302.

[0198] In one embodiment, the transceiver 300 receives transmission beams (e.g., TX0, TX1, TX2, TX3, TX4, TX5, TX6, TX7, etc.) at a port 306 coupled to the LIDAR pixel array 304 via a plurality of waveguides (e.g., waveguide 342). Although eight transmission signals (e.g., TX0 - 7) and sixteen reception signals (reception signals RXS0 - 7 and RXP0 - 7) are shown, according to various embodiments of the present disclosure, more or fewer numbers of transmission and reception signals can be implemented within the transceiver 300.

[0199] Figure 4 shows an exemplary local oscillator module 499 according to an embodiment of the present disclosure. The local oscillator module 499 may include a plurality of optical switches such as optical switches 400, 401, 402, 403, 404, 405, 406, 407, 408, 409, 410, 411, 412, and 413. Each optical switch is controlled by a corresponding control input X0, X1, X2, X3, X4, X5, X6, X7, X8, X9, X10, X11, X12 and X13. For example, the control input may be coupled to the processing logic 299. The processing logic 299 can drive the optical switches via the respective control inputs and direct the local oscillator signal to a specific LIDAR pixel at a specific time. In one embodiment, the processing logic 299 drives the optical switches and directs the local oscillator signal to only one specific LIDAR pixel at a given time. The local oscillator module 499 may be referred to as a "2-to-2n" distribution network for the function of dynamically routing two signals to 2n ports, where n is a number. In the embodiment of FIG. 4, n is 8 and the output ports are 16 (2n). In one embodiment, the local oscillator module may be a "3-to-3n" distribution network for the function of dynamically routing three signals to 3n ports (where n is a number). In another embodiment, the local oscillator module may be a "5-to-5n" distribution network for the function of dynamically routing five signals to 5n ports (where n is a number). In this embodiment, a specific distribution network can be selected to achieve preferred dynamic routing and optimal signal processing.

[0200] In FIG. 4, the optical switch 400 is configured to receive a first local oscillator signal LOS434, and the optical switch 401 is configured to receive a second local oscillator signal LOP436. In FIG. 4, the dashed line indicates the waveguide that provides the first local oscillator signal 434, and the solid line indicates the waveguide that provides the second local oscillator signal 436. In FIG. 4, the component 441 represents a waveguide intersection. In some embodiments of the local oscillator module 499, a plurality of waveguide levels are included, but the waveguides do not necessarily pass through each other, so the waveguide intersection component 441 is not necessarily required.

[0201] In one embodiment, by driving the control input to digital high (e.g., 3.3 VDC), the optical switch is oriented to direct the input light to the left output port, and by driving the control input to digital low (e.g., 0 VDC), the optical switch is oriented to direct the input light to the right output port. For example, to provide the first local oscillator signal 434 and the second local oscillator signal 436 to the first LIDAR pixel, the control inputs X0, X1, X2, X3, X6, and X7 are driven to digital high such that the first local oscillator signal 434 is directed to port LOS480S and the second local oscillator signal 436 is directed to port LOP 480P. To provide the first local oscillator signal 434 and the second local oscillator signal 436 to the second LIDAR pixel, the input ports X0, X1, X2, and X3 are driven to digital high, the input ports X6 and X7 are driven to digital low, and the first local oscillator signal 434 is directed to port LOS481S and the second local oscillator signal 436 is directed to port LOP 481P. In some embodiments, the signals of the control inputs X0, X1, X2, X3, X6, and X7 are analog signals. The processing logic 299 can facilitate the generation of beat signals for the beam-emitting LIDAR pixels by continuously driving the control inputs of the optical switch and raster scanning a plurality of LIDAR pixels to provide the first local oscillator signal 434 and the second local oscillator signal 436. The third, fourth, fifth, sixth, seventh, and eighth LIDAR pixels can receive the first local oscillator signal 434 and the second local oscillator signal 436 by driving the control ports of the optical switch.For example, the third LIDAR pixel may receive the first local oscillator signal 434 and the second local oscillator signal 436 via port LOS 482S and LOP 482P, the fourth LIDAR pixel may receive the first local oscillator signal 434 and the second local oscillator signal 436 via port LOS 483S and LOP 483P, the fifth LIDAR pixel may receive the first local oscillator signal 434 and the second local oscillator signal 436 via port LOS 484S and LOP 484P, the sixth LIDAR pixel may receive the first local oscillator signal 434 and the second local oscillator signal 436 via port LOS 485S and LOP 485P, the seventh LIDAR pixel may receive the first local oscillator signal 434 and the second local oscillator signal 436 via port LOS 486S and LOP 486P, and the eighth LIDAR pixel may receive the first local oscillator signal 434 and the second local oscillator signal 436 via port LOS 487S and LOP 487P.

[0202] FIG. 5 shows an exemplary transmission beam module 599 according to an embodiment of the present disclosure. The transmission beam module 599 may include a plurality of optical switches such as optical switches 500, 501, 502, 503, 504, 505, and 506. Each optical switch is controlled by a corresponding control input X20, X21, X22, X23, X24, X25, and X26. The control inputs may be coupled to, for example, the processing logic 299. The processing logic 299 may drive the optical switches via the respective control inputs and direct the transmission beam to a specific LIDAR pixel at a specific time. In one embodiment, the processing logic 299 drives the optical switches and directs the transmission beam to only one specific LIDAR pixel at a given time.

[0203] In FIG. 5, the optical switch 500 is configured to receive the transmission beam 513. The component 541 in FIG. 5 represents a waveguide intersection. In one embodiment, by driving a digital high (e.g., 3.3 VDC) on the control input, the optical switch is directed to output the input light to the left output port, and by driving a digital low (e.g., 0 VDC) on the control input, the optical switch is directed to output the input light to the right output port. For example, to provide the transmission beam 513 to the first LIDAR pixel, the control inputs X20, X21, and X23 are driven to digital high to direct the transmission beam 513 to port TX560. To provide the transmission beam 513 to the second LIDAR pixel, the input ports X22 and X24 are driven to digital high, and the input port X20 is driven to digital low to direct the transmission beam 513 to port TX561. The processing logic 299 can facilitate generating a beat signal for the beam-emitting LIDAR pixel by continuously driving the control inputs of the optical switch and raster scanning a plurality of LIDAR pixels to provide the transmission beam 513. The third, fourth, fifth, sixth, seventh, and eighth LIDAR pixels can drive the control ports of the optical switch to receive the transmission beam 513 and provide the transmission beam 513 to ports TX562, TX563, TX564, TX565, TX566, and TX567.

[0204] FIG. 6 shows an exemplary LIDAR pixel 699 that includes a first coherent receiver 621 and a second coherent receiver 626 according to an embodiment of the present disclosure. The 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. The transmit optical antenna 605 is configured to emit a transmit beam. The transmit beam can be an infrared transmit beam. The transmit beam can be a near-infrared transmit beam. The transmit beam can have a defined single polarization direction. In FIG. 6, the transmit optical antenna 605 is shown as a single polarization output coupler and can transmit a transmit beam in response to receiving the transmit beam 601 via the waveguide 603. The transmit beam 601 can be generated by a laser, and the transmit beam emitted by the transmit optical antenna 605 can have a very narrow linewidth (e.g., 1 nm or less). The transmit beam 601 can be selectively provided to the transmit optical antenna 605 by the transmit beam module 220.

[0205] As shown in FIG. 6, the receive optical antenna 610 is a dual-polarization receive optical antenna configured to detect a first polarization direction of the return beam and a second polarization direction of the return beam. The return beam is a reflection of the transmit beam reflected by a target in the external environment of the LIDAR system 600. The first polarization direction may be orthogonal to the second polarization direction. The dual-polarization receive optical antenna 610 is configured to couple the first polarization direction of the return beam to the first coherent receiver 621 via the waveguide 612 and couple the second polarization direction of the return beam to the second coherent receiver 626 via the waveguide 617. In one embodiment, the receive optical antenna 610 includes a first polarization receive grating configured to direct the first polarization direction of the return beam to the first coherent receiver 621 and a second polarization receive grating configured to direct the second polarization direction of the return beam to the second coherent receiver 626. In one embodiment, the first polarization receive grating is spaced apart from the second polarization receive grating.

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

[0207] The second coherent receiver 626 is configured to generate a second signal 628 in response to receiving a second polarization direction of the return beam and a second local oscillator signal 636. The second local oscillator signal 636 can be an optical signal having the second polarization direction. The second local oscillator signal 636 can be selectively provided, for example, by the local oscillator module 212. In FIG. 6, the second polarization direction of the return beam is received by the second coherent receiver 626 from the second single-polarization grating coupler 616 through the waveguide 617, and the second local oscillator signal 636 is received by the second coherent receiver 626 through the waveguide 637. The second signal 628 can be an electrical signal provided to the processing logic 650 through the communication channel 627.

[0208] Processing logic 650 is configured to generate an image 655 in response to receiving a first signal 623 and a second signal 628 from a first coherent receiver 621 and a second coherent receiver 626, respectively. The LIDAR system 600 may include an array of LIDAR pixels 699 configured to provide the processing logic 650 with a first signal (e.g., signal 623) and a second signal (e.g., signal 628). Here, the processing logic 650 may generate the image 655 by a plurality of LIDAR pixels 699 in the LIDAR pixel array in response to the first signal and the second signal received by the processing logic 650.

[0209] FIG. 7 shows an exemplary coherent receiver 771 according to an embodiment of the present disclosure. The exemplary coherent receiver 771 of FIG. 7 can be used as the first coherent receiver 621 and / or the second coherent receiver 626 in some embodiments. The coherent receiver 771 includes an optical mixer 752, a return beam port 754, a local oscillator port 758, and an output port 762. In one embodiment, the optical mixer 752 is configured to combine a return beam signal RB and a local oscillator signal LO to generate an output signal OUT. The optical mixer 752 may be coupled to receive the return beam signal RB from, for example, waveguide 612 or waveguide 617, and waveguide 756 may provide the return beam signal to the optical mixer 752. The optical mixer 752 may be coupled to receive the local oscillator signal LO from, for example, waveguide 632 or 637, and waveguide 760 may provide the local oscillator signal LO to the optical mixer 752. The optical mixer 752 may combine the input signals to generate a plurality of combined output signals OUT1 and OUT2. The output signals OUT1 and OUT2 are supplied to a photodiode pair (including photodiodes PD1 and PD2) to convert the return beam signal RB and the local oscillator signal LO into the output signal OUT. The output signal OUT may be an electrical signal. The output signal OUT may be a beat signal representing the distance and / or velocity of one or more objects in the LIDAR system environment. For example, communication channel 622 or 627 may be coupled to the output port 762.

[0210] Figure 8 shows an operation process 800 of a LIDAR device according to an embodiment of the present disclosure. The order in which some or all of the process blocks appear in process 800 should not be regarded as limiting. Rather, those skilled in the art having the advantages of the present disclosure will understand that some of the process blocks may be executed in various orders not shown or executed in parallel.

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

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

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

[0214] In an embodiment 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 can be in a first polarization direction, and the second local oscillator signal can be in a second polarization direction different from the first polarization direction.

[0215] The beam-emitting LIDAR pixel can include a receiving optical antenna for detecting a return beam, and the first optical mixer can be configured to receive a first polarization direction of the return beam. The second optical mixer can be configured to receive a second polarization direction of the return beam.

[0216] In one embodiment, process 800 may further include: (i) selectively directing a transmission beam to a second transmission antenna of a second beam-emitting LIDAR pixel among a plurality of LIDAR pixels; and (ii) selectively directing a first local oscillator signal and a second local oscillator signal to the second beam-emitting LIDAR pixel while the transmission beam is selectively directed to the second beam-emitting LIDAR pixel.

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

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

[0219] FIG. 9 shows a LIDAR system 1200 according to an embodiment of the present disclosure. The LIDAR system 1200 can be an exemplary implementation of the LIDAR sensor 136 (shown in FIG. 1a) and the LIDAR system 104B (shown in FIG. 1b). In an embodiment of the present disclosure, the LIDAR system 1200 includes a laser 1202, a splitter 1204, a polarizer 1206, and a transceiver 1208. The splitter 1204 can be coupled to the laser 1202 to receive a transmission signal 1210. In one embodiment, the splitter 1204 can divide the transmission signal 1210 into transmission signals TX0-7 and local oscillator signals LO1 and LO2. The splitter 1204 can be configured to provide the transmission signals TX0-7 and the local oscillator signals LO1 and LO2 to the transceiver 1208 at a plurality of input ports 1209. Alternatively, according to an embodiment of the present disclosure, the splitter 1204 can be coupled to the polarizer 1206 and configured to provide a first local oscillator signal 1224 and a second local oscillator signal 1226, and the polarizer 1206 can convert this into an S-polarized local oscillator signal LO1 and a P-polarized local oscillator signal LO2. In one embodiment, the local oscillator signals LO1 and LO2 share the same polarization direction, but are used to generate received signals RXS0-7 and RXP0-7 from a receiving optical antenna configured to detect different polarizations at the transceiver 1208.

[0220] In some embodiments, the transceiver 1208 can be configured to receive input signals (e.g., the transmission signals TX0-7 and the local oscillator signals LO1 and LO2), and can be configured to generate output signals (e.g., the received signals RXS0-7 and RXP0-7) in response to the input signals. In one embodiment, the transceiver 1208 can be configured to operate using, for example, one transmission signal TX0 and one local oscillator signal LO1. The transceiver 1208 can include a local oscillator network 1212 and a LIDAR pixel array 1214 configured to support scanning and imaging operations in an autonomous vehicle environment.

[0221] In some embodiments, the local oscillator network 1212 may be configured to receive one or both of the local oscillator signals LO1 and LO2, and may be configured to distribute one or both of the local oscillator signals LO1 and LO2 via the first local oscillator bus 1216 and the second local oscillator bus 1218. The first local oscillator bus 1216 and the second local oscillator bus 1218 may include a plurality of waveguide channels coupled to provide the local oscillator signals LO1 and LO2 to the LIDAR pixel array 1214. The local oscillator network 1212 may be coupled to the LIDAR pixel array 1214 via one or both of the local oscillator buses 1216 and 1218.

[0222] The LIDAR pixel array 1214 may include a plurality of LIDAR pixels, and each of the plurality of LIDAR pixels may be configured to, for example, emit a transmit beam and detect a return beam in response to the transmit signals TX0-7 and the local oscillator signals LO1 and LO2. The LIDAR pixel array 1214 may be configured to generate a plurality of received signals RXS0-7 from the return beam having a first polarization. The LIDAR pixel array 1214 may be configured to generate received signals RXP0-7 from the return beam having a second polarization direction. The LIDAR pixel array 1214 may provide the received signals RXS0-7 on the first return signal bus 1220 and may provide the received signals RXP0-7 on the second return signal bus 1222. The transceiver 1208 may be configured to provide the received signals RXS0-7 and RXP0-7 to a plurality of output ports 1228. According to embodiments of the present disclosure, the received signals RXS0-7 and RXP0-7 may be used by processing logic to generate image data and / or images representative of objects within the LIDAR operating environment.

[0223] Although the transceiver 1208 is described as having eight transmit signals and sixteen receive signals, it should be understood that fewer (e.g., one or two) or more (e.g., hundreds or thousands) transmit or receive signals may be used depending on the various embodiments of the present disclosure.

[0224] FIG. 10a shows an example of a simplified schematic diagram of a LIDAR transceiver 1300 according to an embodiment of the present disclosure. According to an embodiment of the present disclosure, the LIDAR transceiver 1300 includes a local oscillator network 1302, which is coupled to provide a local oscillator signal to the LIDAR pixel array 1304.

[0225] In some embodiments, the local oscillator LO network 1302 is coupled to one or more of a plurality of input ports 1306 via waveguides 1310 and 1312 and may receive one or both of the local oscillator signals LO1 and LO2. According to an embodiment of the present disclosure, the local oscillator network 1302 provides the local oscillator signals LO1 and LO2 to one or more LIDAR pixels of the LIDAR pixel array 1304, and the LIDAR pixels are configured to generate received signals RXS0-7 and RXP0-7 and provide signals to a plurality of output ports 1308.

[0226] In some embodiments, the LIDAR pixel array 1304 may include a plurality of LIDAR pixels arranged along one or two dimensions of the footprint of the LIDAR transceiver 1300. According to one embodiment, the LIDAR pixel 1314 is an example of one or more LIDAR pixels of the LIDAR pixel array 1304. According to one embodiment, the LIDAR pixel 1314 may receive a transmission signal at port 1316, receive the local oscillator signal LO1 at port 1318, and receive the local oscillator signal LO2 at port 1320. The LIDAR pixel 1314 may be configured to generate a received signal RXS and / or a received signal RXP and may provide one or both of the received signals RXS and RXP to ports 1322 and 1324, respectively, according to an embodiment of the present disclosure. In one embodiment, the LIDAR pixel 1314 receives a transmission signal, receives one local oscillator signal, and provides a single received signal.

[0227] According to one embodiment of the present disclosure, the LIDAR pixel 1314 may include an optical antenna array 1326, a receiver circuit 1328, and an optical rotor 1330. The optical antenna array 1326 may include at least one transmit optical antenna configured to receive a transmit signal and emit a transmit beam into the LIDAR environment. The optical antenna array 1326 may include a first receive optical antenna configured to detect a first polarization direction of the return beam, may include a second receive optical antenna configured to detect a second polarization direction of the return beam, or may include both the first receive optical antenna and the second receive optical antenna. The first polarization direction may be orthogonal to the second polarization direction. The receive circuit 1328 may be configured to convert an optical signal into an electrical signal, for example, a receive signal RXS and a receive signal RXP. The receive circuit 1328 may include one or more photodiode pairs configured to receive light and generate an electrical signal in response to the received light. The optical rotor 1330 may be positioned between the optical antenna array 1326 and the receiver circuit 1328. The optical rotor 1330 may be configured to provide a transmit signal to the optical antenna array 1326 and may be configured to provide a return signal from a return optical antenna to the receiver circuit 1328 to support the generation of the receive signals RXS and RXP. The optical rotor 1330 can be implemented as a polarization beam splitter in an optical waveguide, but may be configured to operate as a rotor for providing a transmit signal to a transmit antenna and a receive signal to a receive circuit (e.g., an optical mixer and / or a photodiode).

[0228] In some embodiments, the LIDAR transceiver 1300 may include a power monitor array configured to detect the power of each transmission signal provided to the LIDAR pixels of the LIDAR pixel array 1304. The power monitor array may include one power monitor for each LIDAR pixel of the LIDAR pixel array 1304. The power monitor 1332 may be an example of a power monitor of the power monitor array. The power monitor 1332 may include a waveguide 1334, a waveguide 1336, and a photodiode 1338. Since the transmission signal can propagate through the waveguide 1334, the waveguide 1334 may be disposed in-line with the transmission signal waveguide. The waveguide 1336 may be located near the waveguide 1334 to receive a portion of the transmission signal. The photodiode 1338 may be coupled to the waveguide 1336 and may be configured to convert a portion of the transmission signal into an electrical signal to support power monitoring operations. The LIDAR transceiver 1300 may include a plurality of output ports 1340 communicatively coupled to the power monitors of the power monitor array and configured to provide an external power monitor output to the LIDAR transceiver 1300.

[0229] According to one embodiment, the LIDAR transceiver 1300 receives transmission signals (e.g., TX0, TX1, TX2, TX3, TX4, TX5, TX6, TX7, etc.) from a portion of the port 1306 coupled to the LIDAR pixel array 1304 via a plurality of waveguides (e.g., waveguide 1342). Although eight transmission signals (e.g., TX0 - 7) and sixteen reception signals (reception signals RXS0 - 7 and RXP0 - 7) are illustrated, according to various embodiments of the present disclosure, more or fewer numbers of transmission and reception signals can be implemented with the LIDAR transceiver 1300.

[0230] FIG. 10b shows a LIDAR transceiver 1350 according to an embodiment of the present disclosure. The LIDAR transceiver 1350 may include splitters 1352 and 1354 configured to distribute a transmission signal from input port 1306. Splitters 1352 and 1354 can be implemented as passive splitters that include a plurality of optical splitters configured to receive one optical signal and split the optical signal into a plurality of output ports (e.g., four ports) to support the operation of the LIDAR pixels of the LIDAR pixel array 1304. According to various embodiments, splitters 1352 and 1354 may be 1-to-4 splitters or may be configured to split the transmission signal into more signals (e.g., 8, 16, 32, 64, etc.). Using splitters 1352 and 1354 can reduce noise due to crosstalk and reduce the burden associated with waveguide routing within the LIDAR transceiver 1350.

[0231] Figure 11 shows a LIDAR system 1400 including a LIDAR pixel 1499 according to an embodiment of the present disclosure. The LIDAR pixel 1499 may include an optical antenna array 1460, which may be an embodiment of the optical antenna array 1326 (shown in FIGS. 10a and 10b). The 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 specific LIDAR pixel architecture shown in FIG. 11. Any suitable chip design architecture can be used to implement the LIDAR pixel. For example, the transmit and receive optical antennas may be implemented as a single module or a single integrated chip, or may be implemented as separate modules or chips. As another example, the first and second coherent receivers may be implemented as a single module or a single integrated chip, or may be implemented as separate modules or chips. The transmit optical antenna 1405 may 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 have a defined single polarization direction. In FIG. 11, the transmit optical antenna 1405 is shown as a single polarization output coupler and, according to one embodiment, may transmit a transmit beam in response to receiving a transmit signal 1401 via a waveguide 1403. The transmit signal 1401 may be generated by a laser, and the transmit beam emitted by the transmit optical antenna 1405 may have a very narrow linewidth (e.g., 1 nm or less).

[0232] In some embodiments, the received optical antenna 1410 can be a dual-polarization received optical antenna configured to detect a first polarization direction of the return beam and a second polarization direction of the return beam. The return beam can be a reflection of the transmitted beam reflected from an object within the external environment of the LIDAR system 1400. The first polarization direction may be orthogonal to the second polarization direction. In some embodiments, the orthogonality can have a margin range exceeding 0 to 10%. For example, when the first polarization direction has an angle between 80 degrees and 100 degrees with respect to the second polarization direction, it can be defined as orthogonal. The first polarization direction may be S polarization, the second polarization direction may be P polarization, and vice versa. In FIG. 11, the received optical antenna 1410 includes a first single-polarization grating coupler 1411 and a second single-polarization grating coupler 1416. The first single-polarization grating coupler 1411 can be configured to couple the first polarization direction of the return beam to the first coherent receiver 1421 via the waveguide 1412. The second single-polarization grating coupler 1416 can be configured to couple the second polarization direction of the return beam to the second coherent receiver 1426 via the waveguide 1417. The transmitted optical antenna 1405 can be configured to emit the transmitted beam in the second polarization direction or in the first polarization direction as shown.

[0233] The first single-polarization grating coupler 1411 can be rotated with respect to the second single-polarization grating coupler 1416. In the specific exemplary embodiment of FIG. 11, the first single-polarization grating coupler 1411 is rotated 90 degrees with respect to the second single-polarization grating coupler 1416. The single-polarization output coupler of the illustrated transmitted optical antenna 1405 can be rotated with respect to the first single-polarization grating coupler 1411 and can include a direction similar to that of the second single-polarization grating coupler 1416. In particular, according to one embodiment, the first single-polarization grating coupler 1411 can be rotated +45 degrees, the transmitted optical antenna 1405 can be rotated -45 degrees, the second single-polarization grating coupler 1416 can be rotated -45 degrees, and the first single-polarization grating coupler 1411 can be rotated +45 degrees.

[0234] In some embodiments, the transmit optical antenna 1405, the first single-polarization grating coupler 1411, and the second single-polarization grating coupler 1416 may be positioned in a one-dimensional line to receive a return beam (e.g., received from a rotating mirror) that can affect the optical antenna array 1460 at a position offset from the transmit optical antenna 405, for example, due to the pitch-catch characteristics of transmitting and receiving LIDAR signals with a rotating mirror. For example, the first single-polarization grating coupler 1411 may be offset from the transmit optical antenna 1405 by a distance D1, and the second single-polarization grating coupler 1416 may be positioned between the first single-polarization grating coupler 1411 and the transmit optical antenna 1405. The second single-polarization grating coupler 1416 may be offset from the transmit optical antenna 1405 by a second distance D2 in the optical antenna array 1460. The first single-polarization grating coupler 1411 may be offset from the second single-polarization grating coupler 1416 by a third distance D3.

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

[0236] In some embodiments, the first coherent receiver 1421 may include an optical mixer 1462 and a photodiode pair 1464 for converting the received optical signal into an electrical signal. The optical mixer 1462 may be coupled to receive the local oscillator signal LO1 and a signal indicating the first polarization direction of the return beam from the first single polarization grating coupler 1411. The optical mixer 1462 may be coupled to the photodiode pair 1464 to provide a mixed output signal. The photodiode pair 1464 may be configured to generate a first signal 1423 and provide the first signal 1423 to the processing logic 1450 via the communication channel 1422. The first signal 1423 may be an example of a received signal RXS (e.g., as shown in FIGS. 10a and 10b). The number of output signals from the optical mixer is not limited to a particular number and may be any suitable number.

[0237] In some embodiments, the second coherent receiver 1426 may be configured to generate a second signal 1428 in response to receiving the second polarization direction of the return beam and the second local oscillator signal 1436. The second local oscillator signal 1436 may be an optical signal having the second polarization direction and may be the local oscillator signal LO2. In FIG. 11, the second polarization direction of the return beam may be received by the second coherent receiver 1426 from the second single polarization grating coupler 1416 via the waveguide 1417, and the second local oscillator signal 1436 may be received by the second coherent receiver 1426 via the waveguide 1437. The second signal 1428 may be an electrical signal provided to the processing logic 1450 via the communication channel 1427.

[0238] In some embodiments, the second coherent receiver 1426 may include an optical mixer 1466 and a photodiode pair 1468 for converting the received optical signal into an electrical signal. The optical mixer 1466 may be coupled to receive the local oscillator signal LO2 and a signal indicating the second polarization direction of the return beam from the second single polarization grating coupler 1416. The optical mixer 1466 may be coupled to the photodiode pair 1468 to provide a mixed output signal. The photodiode pair 1468 may be configured to generate a second signal 1428 and provide the second signal 1428 to the processing logic 1450 via the communication channel 1427. The second signal 1428 may be an example of a received signal RXP (e.g., as shown in FIGS. 10a and 10b). The number of output signals from the optical mixer is not limited to a particular number and may be any suitable number.

[0239] In some embodiments, the received optical signal, the transmitted signal (before emission), and the local oscillator signal may have the same polarization direction while in the on-chip (e.g., while propagating through a waveguide). One or more optical antennas may be configured to change (e.g., rotate) the polarization direction of the return beam and the transmitted beam to one or more particular polarization directions. For example, an optical antenna may be configured to convert a return beam having a first polarization direction into a return signal having a second or third polarization direction in the waveguide. As another example, the transmitted signal may have a third direction while in the waveguide, and the optical antenna may be configured to couple the transmitted signal into free space as a transmitted beam having a first or second polarization direction.

[0240] Processing logic 1450 may be configured to generate an image 1455 in response to receiving a first signal 1423 and a second signal 1428 from a first coherent receiver 1421 and a second coherent receiver 1426, respectively. The LIDAR system 1400 may include an array of LIDAR pixels 1499 configured to provide the processing logic 1450 with a first signal (e.g., signal 1423) and a second signal (e.g., signal 1428). Here, the processing logic 1450 may generate the image 1455 in response to the first signal and the second signal received by the processing logic 1450, by a plurality of LIDAR pixels 1499 within the LIDAR pixel array.

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

[0242] Figures 12a and 12b show simplified block diagrams of LIDAR devices having a stacked antenna configuration according to embodiments of the present disclosure. Figure 12a shows an example of a LIDAR device 1500 in which a first semiconductor layer 1502 is stacked on a second semiconductor layer 1504. The LIDAR device 1500 may include a transmit optical antenna 1506 and a receive optical antenna 1508. The transmit optical antenna 1506 may be configured to emit a transmit beam having a second polarization direction as an exemplary embodiment of the transmit optical antenna 1405 (shown in FIG. 11). The receive optical antenna 1508 may be an exemplary embodiment of the second single polarization grating coupler 1416 (shown in FIG. 11) and may be configured to detect a return beam having a second polarization direction. The second semiconductor layer 1504 may be an exemplary embodiment of the first single polarization grating coupler 1411 (shown in FIG. 11) and may include a second receive optical antenna 1510 configured to detect a return beam having a first polarization direction. The receive optical antenna 1508 may be offset from the transmit optical antenna 1506 and may be located in the first semiconductor layer stacked on the second semiconductor layer. The first semiconductor layer 1502 may be an alloy composed of one or more of group III or group V elements of the periodic table. The second semiconductor layer 1504 may be formed from a silicon substrate or nitride.

[0243] Figure 12b shows an example of a LIDAR device 1550 that includes a first semiconductor layer 1552 stacked on a second semiconductor layer 1554 and is configured to provide stacked optical antenna LIDAR operation. According to embodiments of the present disclosure, the first semiconductor layer 1552 may include a transmit optical antenna 1506, and the second semiconductor layer 1554 may include receive optical antennas 1508 and 1510 that are offset from each other and are arranged to receive a LIDAR return beam through the first semiconductor layer 1552.

[0244] In the present disclosure, the term "processing logic" (e.g., processing logic 299 or processing logic 650) may include one or more processors, microprocessors, multi-core processors, application specific integrated circuits (ASICs), and / or field programmable gate arrays (FPGAs) for performing the operations disclosed herein. In some embodiments, a memory (not shown) is integrated with the processing logic to store instructions for performing operations and / or storing data. Also, the processing logic may include analog or digital circuitry for performing operations according to embodiments of the present disclosure.

[0245] As used herein, "memory" or "memories" may include one or more volatile or non-volatile memory architectures. "Memory" or "memories" may be removable and non-removable media embodied in any method or technology for storing information such as computer-readable instructions, data structures, program modules, or other data. Examples of memory technologies may include RAM, ROM, EEPROM, flash memory, CD-ROM, DVD, high definition multimedia / data storage disks or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage, other magnetic storage devices or other non-transmission media that can be used to store information accessible by a computing device.

[0246] Networks can include, but are not limited to, all networks or network systems such as peer-to-peer networks, LANs (local area networks), WANs (wide area networks), public networks such as the Internet, private networks, cellular networks, wireless networks, wired networks, wired and wireless combined networks, and satellite networks.

[0247] Communication channels include the IEEE802.11 protocol, Bluetooth, SPI (Serial Peripheral Interface), I 2C, USB (Universal Serial Port), CAN (Controller Area Network), cellular data protocols (e.g., 3G, 4G, LTE, 5G, etc.), optical communication networks, Internet Service Providers (ISPs), peer-to-peer networks, LANs, WANs, public networks (e.g., the "Internet"), private networks, satellite networks, or others, including or capable of being routed by one or more wired or wireless communications.

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

[0249] The processes described above are explained in terms of computer software and hardware aspects. The described technology can be composed of machine-executable instructions embodied in a tangible or non-transitory machine (e.g., a computer) readable storage medium, which, when executed by a machine, causes the machine to perform the described operations. Additionally, the process can be implemented in hardware such as an Application Specific Integrated Circuit ("ASIC").

[0250] A tangible non-transitory machine readable storage medium includes all mechanisms that provide (i.e., store) information in a form accessible by a machine (e.g., a computer, a network device, a personal digital assistant, a manufacturing tool, any device with one or more processor sets, etc.). For example, the machine readable storage medium includes recordable / non-recordable media (e.g., Read Only Memory (ROM), Random Access Memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, etc.).

[0251] The foregoing description of the exemplary 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. Specific embodiments and examples of the invention are described herein for illustrative purposes, but various modifications can be made within the scope of the invention, as will be recognized by those skilled in the relevant art.

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

Claims

1. A light detection and distance measurement (LIDAR) sensor, wherein the LIDAR sensor is A light source configured to emit a light beam, A splitter configured to divide the aforementioned optical beam into a transmit beam and a local oscillator signal, Multiple emitters, A switching device configured to receive the transmitted beam, comprising a plurality of optical switches arranged in a multilayer configuration and capable of sequentially transmitting the optical beam to a plurality of emitters, A LiDAR sensor comprising a local oscillator module coupled to the plurality of emitters, configured to receive a first local oscillator (LOS) signal and a second local oscillator (LOP) signal, and including a plurality of alternating output ports corresponding to the LOS and LOP signals, wherein adjacent pairs of LOS and LOP output ports are coupled to one of the plurality of emitters.

2. The multilayer configuration is Among the plurality of optical switches, the first layer includes the first group, A second layer comprising a second group of optical switches, wherein the second group comprises more optical switches than the first group. The LIDAR sensor according to claim 1, further comprising: a third layer including a third group of the plurality of optical switches, wherein the third group includes more optical switches than the second group.

3. The first group includes one optical switch, The second group includes two optical switches, The third group is the LIDAR sensor according to claim 2, comprising four optical switches.

4. The LIDAR sensor according to claim 2, further comprising an optical device that couples one optical switch of the second group to two optical switches of the third group, wherein the switching device is further comprising an optical device.

5. The LIDAR sensor according to claim 4, wherein the optical device includes a waveguide intersection.

6. The LIDAR sensor according to claim 1, wherein the plurality of optical switches are controlled independently.

7. The LIDAR sensor according to claim 1, wherein the plurality of optical switches are operable to transmit the transmission beam to the plurality of emitters one at a time.

8. The LIDAR sensor according to claim 1, wherein the transmission beam emitted by the first emitter among the plurality of emitters is reflected from an object as a return beam and received by the first emitter.

9. The LIDAR sensor according to claim 8, wherein the first emitter includes a transmitting circuit configured to transmit the transmit beam and a receiving circuit configured to receive the return beam.

10. The LIDAR sensor according to claim 1, wherein the light source is a laser.

11. The LIDAR sensor according to claim 1, wherein the local oscillator module is arranged in the multilayer configuration and includes a plurality of optical switches that can operate to sequentially transmit the first local oscillator signal and the second local oscillator signal to the plurality of emitters.

12. The LIDAR sensor according to claim 11, further comprising a polarization module coupled between the local oscillator module and the splitter, configured to receive the local oscillator signal and output the first local oscillator signal and the second local oscillator signal to the local oscillator module, wherein the first local oscillator signal has a first polarization direction and the second local oscillator signal has a second polarization direction different from the first polarization direction.

13. The LIDAR sensor according to claim 12, wherein the second polarization direction is perpendicular to the first polarization direction.

14. The LIDAR sensor according to claim 12, wherein at least one of the plurality of emitters is a first light antenna configured to emit the light beam into the surrounding environment and a second light antenna configured to detect the return beam.

15. The LIDAR sensor according to claim 14, wherein the second optical antenna includes a bipolarized optical antenna configured to detect the first polarization direction and the second polarization direction of the return beam.

16. At least the first emitter among the plurality of emitters is A first coherent receiver configured to generate a first signal in response to receiving the first local oscillator signal and the first polarization direction of the return beam, The LIDAR sensor according to claim 15, further comprising a second coherent receiver configured to generate a second signal in response to receiving the second local oscillator signal and the second polarization direction of the return beam.

17. A first interface for optically coupling the switching device to the plurality of emitters, The LIDAR sensor according to claim 11, further comprising a second interface for optically coupling the local oscillator module to the plurality of emitters.

18. The LIDAR sensor according to claim 1, further comprising a plurality of power monitors configured to monitor the amount of power of the transmission beam emitted by each of the plurality of emitters.

19. An autonomous vehicle control system, The system includes a light detection and distance measurement (LIDAR) system, and the LIDAR system is A light source configured to emit a light beam, A splitter configured to divide the aforementioned optical beam into a transmit beam and a local oscillator signal, Multiple emitters, A switching device configured to receive the transmitted beam, comprising a plurality of optical switches arranged in a multilayer configuration and capable of sequentially transmitting the optical beam to a plurality of emitters, An autonomous vehicle control system comprising: a local oscillator module coupled to the plurality of emitters, configured to receive a first local oscillator (LOS) signal and a second local oscillator (LOP) signal, and including a plurality of alternating output ports corresponding to the LOS and LOP signals, wherein adjacent pairs of LOS and LOP output ports are coupled to emitters among the plurality of emitters.

20. An autonomous vehicle, The system includes a light detection and distance measurement (LIDAR) system, and the LIDAR system is A light source configured to emit a light beam, A splitter configured to divide the aforementioned optical beam into a transmit beam and a local oscillator signal, Multiple emitters, A switching device configured to receive the transmitted beam, comprising a plurality of optical switches arranged in a multilayer configuration and capable of sequentially transmitting the optical beam to a plurality of emitters, An autonomous vehicle comprising a local oscillator module coupled to the plurality of emitters, configured to receive a first local oscillator (LOS) signal and a second local oscillator (LOP) signal, and including a plurality of alternating output ports corresponding to the LOS and LOP signals, wherein adjacent pairs of LOS and LOP output ports are coupled to emitters among the plurality of emitters.

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