Light detection and ranging (LIDAR) sensor system including seed modulation module

Abstract

A light detection and ranging (lidar) system for a vehicle may include an input optical path, a first optical path, a plurality of second optical paths, a first optical amplifier, and a plurality of second optical amplifiers. The input light path may be configured to receive a light beam from a laser source. The first optical path and the plurality of second optical paths may be branched from the input optical path, respectively. A first optical amplifier may be coupled to the first optical path and configured to output a local oscillator (LO) signal. The plurality of second optical amplifiers may be coupled to the plurality of second optical paths, respectively, one of the plurality of second optical amplifiers being selectively turned on to modulate the light beam received through the second optical path and output a modulated optical signal of the light beam.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of and priority to U.S. Patent Application No. 17 / 888,364, filed on August 15, 2022 (now U.S. Patent No. 11,619,716), the disclosure of which is hereby incorporated by reference in its entirety. Background Art

[0003] Light detection and ranging (lidar) sensor systems are used in a variety of applications, from altimetry to imaging to collision avoidance. Lidar provides finer-scale range resolution with smaller beam sizes than conventional microwave ranging systems such as radio wave detection and ranging (radar). Optical detection of range can be achieved by several different techniques, including direct ranging based on the round-trip travel time of an optical pulse to an object, chirp detection based on the frequency difference between an emitted chirped optical signal and the return signal scattered from the object, and phase coded detection based on a series of single-frequency phase changes that are distinguishable from natural signals.

[0004] When applying these techniques, the lidar sensor system may include a modulator configured to receive an optical signal from a laser source and modulate the optical signal before emitting the optical signal into the environment. The lidar sensor system may also use time-separated I / Q processing (aka time domain multiplexing) to overcome hardware requirements. For example, multiple transmit (TX) channels may be time-multiplexed to share limited hardware resources (eg, receive (RX) end hardware resources). A mechanism is needed to efficiently perform modulation and multiplexing using limited hardware resources. Summary of the invention

[0005] Embodiments of the present disclosure relate to a system and method for a light detection and ranging (lidar) sensor system, and more particularly, to a system and method for a lidar sensor system including a seed modulation module.

[0006] In some embodiments of the present disclosure, a device may include an input optical path, a first optical path, a plurality of second optical paths, a first optical amplifier, a plurality of second optical amplifiers, and a control circuit. The input optical path may be configured to receive a light beam from a laser source at one end thereof. The first optical path and the plurality of second optical paths may be branched from the other end of the input optical path, respectively. The first optical amplifier may be coupled to the first optical path. The plurality of second optical amplifiers may be coupled to the plurality of second optical paths, respectively. The control circuit may be configured to selectively turn on one of the plurality of second optical amplifiers to output a modulated optical signal of the light beam. The control circuit may be configured to turn on the first optical amplifier synchronously with turning on any one of the plurality of second optical amplifiers to output a local oscillator (LO) signal.

[0007] In some embodiments of the present disclosure, an autonomous vehicle control system may include one or more processors and one or more computer-readable storage media. The medium may store instructions that, when executed by one or more processors, cause one or more processors to generate an optical signal that is frequency-shifted by a frequency offset relative to a local oscillator (LO) signal based on a light beam generated from a laser source. One or more processors may be configured to transmit the optical signal to an environment. In response to transmitting the optical signal, one or more processors may be configured to receive a return optical signal reflected from an object in the environment. One or more processors may be configured to generate a digital signal based on the received signal. One or more processors may be configured to digitally mix the digital signal based on the frequency offset to generate a sample signal. One or more processors may be configured to determine a range to an object based on the sample signal. One or more processors may be configured to use the range to the object to control the operation of the vehicle.

[0008] In some embodiments of the present disclosure, a light detection and ranging (lidar) system may include the device, a laser source configured to generate a light beam, a plurality of transmit (TX) channels, and one or more optical components. The one or more optical components may be configured to receive a first modulated optical signal and a first LO signal associated with the first modulated optical signal from the device. The one or more optical components may be configured to receive a second modulated optical signal and a second LO signal associated with the second modulated optical signal from the device. The one or more optical components may be configured to transmit the first modulated optical signal and the second modulated optical signal to the environment at a first TX channel and a second TX channel among the plurality of TX channels, respectively. The one or more optical components may be configured to receive a first return optical signal and a second return optical signal reflected from one or more objects in the environment. The one or more optical components may be configured to pair the first return optical signal and the second return optical signal with the first LO signal and the second LO signal, respectively.

[0009] In some embodiments of the present disclosure, a method for generating a modulated optical signal in a circuit may include receiving, by the circuit, a light beam from a laser source at an input optical path of the circuit. The circuit may include an input optical path, a first optical path and a plurality of second optical paths respectively branching from the input optical path, a first optical amplifier coupled to the first optical path, and a plurality of second optical amplifiers respectively coupled to the plurality of second optical paths. The method may include receiving, by the circuit, a light beam from a laser source at the input optical path. The method may include selectively turning on, by the circuit, one of the plurality of second optical amplifiers to output a modulated optical signal of the light beam. The method may include turning on, by the circuit, the first optical amplifier in synchronization with turning on any one of the plurality of second optical amplifiers to output a local oscillator (LO) signal.

[0010] In some embodiments of the present disclosure, a light detection and ranging (lidar) system for a vehicle may include an input optical path configured to receive a light beam from a laser source, a first optical path and a plurality of second optical paths respectively branched from the input optical path, a first optical amplifier coupled to the first optical path and configured to output a local oscillator (LO) signal, and a plurality of second optical amplifiers respectively coupled to the plurality of second optical paths. One of the plurality of second optical amplifiers may be selectively turned on to modulate the light beam received through the second optical path and output a modulated optical signal of the light beam.

[0011] In some embodiments of the present disclosure, an autonomous vehicle may include at least one of a light detection and ranging (lidar) system, a steering system or a braking system, and a vehicle controller including one or more processors. The lidar system may include an input optical path configured to receive a light beam from a laser source, a first optical path and a plurality of second optical paths respectively branched from the input optical path, a first optical amplifier coupled to the first optical path and configured to output a local oscillator (LO) signal, and a plurality of second optical amplifiers respectively coupled to the plurality of second optical paths. One of the plurality of second optical amplifiers may be selectively turned on to modulate the light beam received through the second optical path and output a modulated optical signal of the light beam. The one or more processors may be configured to operate the lidar system to transmit a modulated optical signal to an environment, receive a return optical signal reflected from an object in the environment, pair the return optical signal with the LO signal to generate an electrical signal, and use the electrical signal to control at least one of the steering system or the braking system. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] This patent or application file contains at least one drawing printed in color. Copies of this patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0013] These and other aspects and features of the present embodiment will become apparent to those of ordinary skill in the art after reading the following description of the specific embodiment in conjunction with the accompanying drawings, in which:

[0014] Figure 1A is a block diagram illustrating an example of a system environment for an autonomous vehicle according to some implementations.

[0015] Figure 1B is a block diagram illustrating an example of a system environment for an autonomous commercial truck according to some implementations.

[0016] Figure 1C is a block diagram illustrating an example of a system environment for an autonomous commercial truck according to some implementations.

[0017] Figure 1D is a block diagram illustrating an example of a system environment for an autonomous commercial truck according to some implementations.

[0018] Figure 2 is a block diagram illustrating an example of a lidar system for an autonomous vehicle according to some implementations.

[0019] Figure 3A is a block diagram illustrating an example of a lidar system according to some implementations.

[0020] Figure 3B is a block diagram illustrating an example of a seed modulation device according to some embodiments.

[0021] Figure 3C is a block diagram illustrating an example of a seed brewing assembly according to some implementations.

[0022] Figure 4 is a block diagram illustrating another example of a lidar system according to some embodiments.

[0023] Figure 5 is a flow chart illustrating an example method for generating a modulated optical signal using a seed modulation device according to some embodiments.

[0024] Figure 6 is a flow chart illustrating an example method for controlling a lidar system using a seed modulation device according to some implementations.

[0025] Figure 7 is a block diagram illustrating an example of a computing system according to some implementations. DETAILED DESCRIPTION

[0026] According to certain aspects, implementations in the present disclosure relate to systems and methods for controlling a vehicle using light detection and ranging (lidar), and more particularly, to systems and methods for a lidar sensor system including a seed modulation module.

[0027] According to certain aspects, a device may include an input optical path, a first optical path, a plurality of second optical paths, a first optical amplifier, a plurality of second optical amplifiers, and a control circuit. The input optical path may be configured to receive a light beam from a laser source at one end thereof. The first optical path and the plurality of second optical paths may be branched from the other end of the input optical path, respectively. The first optical amplifier may be coupled to the first optical path. The plurality of second optical amplifiers may be coupled to the plurality of second optical paths, respectively. The control circuit may be configured to selectively turn on one of the plurality of second optical amplifiers to output a modulated optical signal of the light beam. The control circuit may be configured to turn on the first optical amplifier synchronously with turning on any one of the plurality of second optical amplifiers to output a local oscillator (LO) signal.

[0028] 1. Autonomous vehicle system environment

[0029] Figure 1A is a block diagram illustrating an example of a system environment for an autonomous vehicle according to some implementations.

[0030] refer to Figure 1A , an example autonomous vehicle 110A in which the various techniques disclosed herein may be implemented. For example, the vehicle 110A may include a powertrain 192 including a prime mover 194 driven by an energy source 196 and capable of providing power to a drivetrain 198; and a control system 180 including a directional control 182, a powertrain control 184, and a brake control 186. The vehicle 110A may be implemented as any number of different types of vehicles, including vehicles capable of transporting people and / or cargo, and vehicles capable of traveling in a variety of environments, and it should be understood that the above-described components 180-198 may vary widely based on the type of vehicle in which they are used.

[0031] For simplicity, the embodiments discussed below will focus on wheeled land vehicles, such as cars, vans, trucks, buses, etc. In such embodiments, the prime mover 194 may include one or more electric motors and / or internal combustion engines (etc.). The energy source may include, for example, a fuel system (e.g., providing gasoline, diesel, hydrogen, etc.), a battery system, solar panels or other renewable energy sources, and / or a fuel cell system. The transmission system 198 may include: wheels and / or tires and a transmission and / or any other mechanical drive components to convert the output of the prime mover 194 into vehicle motion; and one or more brakes configured to controllably stop or slow the vehicle 110A; and a direction or steering assembly suitable for controlling the trajectory of the vehicle 110A (e.g., a rack and pinion steering linkage that enables one or more wheels of the vehicle 110A to pivot about a generally vertical axis to change the angle of the plane of rotation of the wheel relative to the longitudinal axis of the vehicle). In some embodiments, a combination of power systems and energy sources may be used (e.g., in the case of an electric / gas hybrid vehicle), and in some instances, multiple electric motors (e.g., dedicated to each wheel or axle) may be used as prime movers.

[0032] The directional control 182 may include one or more actuators and / or sensors for controlling and receiving feedback from a directional or steering assembly to enable the vehicle 110A to follow a desired trajectory. The powertrain control 184 may be configured to control the output of the powertrain 102, e.g., controlling the output power of the prime mover 194, controlling the gear of a transmission in the transmission 198, etc., thereby controlling the speed and / or direction of the vehicle 110A. The brake control 116 may be configured to control one or more brakes that slow or stop the vehicle 110A, e.g., disc brakes or drum brakes coupled to the wheels of the vehicle.

[0033] Other vehicle types (including but not limited to off-road vehicles, all-terrain or tracked vehicles, construction equipment, etc.) will necessarily use different powertrains, drivetrains, energy sources, directional controls, powertrain controls, and brake controls. In addition, in some embodiments, some components may be combined, for example, directional control of the vehicle is primarily handled by changing the output of one or more prime movers. Therefore, the embodiments disclosed herein are not limited to the specific application of the technology described herein in autonomous wheeled land vehicles.

[0034] Various levels of autonomous control of the vehicle 110A may be implemented in a vehicle control system 120, which may include one or more processors 122 and one or more memories 124, wherein each processor 122 is configured to execute program code instructions 126 stored in the memory 124. The processors may include, for example, one or more graphics processing units ("GPUs") and / or one or more central processing units ("CPUs").

[0035] The sensor 130 may include various sensors suitable for collecting information from the vehicle's surroundings for controlling vehicle operation. For example, the 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 one of a satellite navigation system (such as GPS (Global Positioning System), GLONASS (Globalnaya Navigazionnaya Sputnikovaya Sistema or Global Navigation Satellite System), Beidou Satellite Navigation 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. The sensor 130 may include a camera 140 and / or an IMU (Inertial Measurement Unit) 142. The camera 140 may be a single or stereo camera and may record static and / or video images. The IMU 142 may include multiple gyroscopes and accelerometers capable of detecting linear and rotational motion of the vehicle in three directions. One or more encoders (not shown) such as wheel encoders may be used to monitor the rotation of one or more wheels of the vehicle 110A. Each sensor 130 may output sensor data at various data rates, which may be different from the data rates of other sensors 130 .

[0036] The output of the sensor 130 may be provided to a set of control subsystems 150, including a positioning subsystem 152, a planning subsystem 156, a perception subsystem 154, and a control subsystem 158. The positioning subsystem 152 may perform functions such as accurately determining the position and orientation (sometimes also referred to as "pose") of the vehicle 110A within its surroundings and generally within a certain reference frame. As part of generating labeled autonomous vehicle data, the position of the autonomous vehicle may be compared with the position of another vehicle in the same environment. The perception subsystem 154 may perform functions such as detecting, tracking, determining, and / or identifying objects within the surroundings of the vehicle 110A. Machine learning models may be used to track objects. The planning subsystem 156 may perform functions such as planning a trajectory for the vehicle 110A within a certain time frame given a desired destination and static and moving objects within the environment. Machine learning may be used to plan a vehicle trajectory. The control subsystem 158 may perform functions such as generating appropriate control signals to control various controls in the vehicle control system 120 to implement the planned trajectory of the vehicle 110A. Machine learning models may be used to generate one or more signals to control the autonomous vehicle to implement the planned trajectory.

[0037] It should be understood that Figure 1A The assembly of components of the vehicle control system 120 shown in FIG. 1 is merely exemplary in nature. In some embodiments, individual sensors may be omitted. Additionally or alternatively, in some embodiments, a Figure 1A Multiple sensors of the type shown in can be used to achieve redundancy and / or cover different areas around the vehicle, and other types of sensors can be used. Similarly, different types and / or combinations of control subsystems can be used in other embodiments. In addition, although the subsystems 152-158 are shown as being separated from the processor 122 and the memory 124, it is understood that in some embodiments, some or all of the functions of the subsystems 152-158 can be implemented by program code instructions 126 residing in one or more memories 124 and executed by one or more processors 122, and these subsystems 152-158 can be implemented using the same processor and / or memory in some instances. The subsystems can be implemented at least in part using various dedicated circuit logic, various processors, various field programmable gate arrays ("FPGA"), various application-specific integrated circuits ("ASIC"), various real-time controllers, etc. As described above, multiple subsystems can utilize circuits, processors, sensors and / or other components. In addition, the various components in the vehicle control system 120 can be networked in various ways.

[0038] In some embodiments, the vehicle 110A may also include an auxiliary vehicle control system (not shown) that may serve as a redundant or backup control system for the vehicle 110A. The auxiliary vehicle control system may be able to fully operate the autonomous vehicle 110A in the event of an adverse event in the vehicle control system 120, while in other embodiments, the auxiliary vehicle control system may have only limited functionality, such as performing a controlled stop of the vehicle 110A in response to an adverse event detected in the primary vehicle control system 120. In other embodiments, the auxiliary vehicle control system may be omitted.

[0039] Typically, a myriad of different architectures (including various combinations of software, hardware, circuit logic, sensors, networks, etc.) can be used to implement Figure 1A . For example, each processor may be implemented as a microprocessor, and each memory may represent a random access memory ("RAM") device, which includes: main storage; and any supplementary levels of memory, such as cache memory, non-volatile or backup memory (such as programmable memory or flash memory), read-only memory, etc. In addition, each memory may be considered to include: memory storage physically located elsewhere in the vehicle 110A, such as any cache memory in the processor; and any storage capacity used as virtual memory, such as it is stored on a mass storage device or another computer controller. Figure 1A One or more of the processors shown in the figure or an entirely separate processor may be used to implement additional functionality in the vehicle 110A beyond autonomous control purposes, such as controlling the entertainment system, operating doors, lights, convenience features, etc.

[0040] In addition, to enable additional storage, the vehicle 110A may include one or more mass storage devices, such as a removable disk drive, a hard drive, a direct access storage device (“DASD”), an optical drive (e.g., a CD drive, a DVD drive, etc.), a solid-state storage drive (“SSD”), a network attached storage, a storage area network, and / or a tape drive, etc.

[0041] Additionally, the vehicle 110A may include a user interface 164 to enable the vehicle 110A to receive a plurality of inputs from and generate outputs for a user or operator, such as one or more displays, touch screens, voice and / or gesture interfaces, buttons and other tactile controls, etc. Otherwise, the user input may be received via another computer or electronic device (e.g., via an application on a mobile device or via a web interface).

[0042] In addition, the vehicle 110A may include one or more network interfaces, such as a network interface 162, which is suitable for communicating with one or more networks 170 (e.g., a local area network ("LAN"), a wide area network ("WAN"), a wireless network, and / or the Internet, etc.) to allow communication of information with other computers and electronic devices, including, for example, a central service, such as a cloud service, from which the vehicle 110A receives environmental and other data for its autonomous control. Data collected by one or more sensors 130 may be uploaded to a computing system 172 via the network 170 for additional processing. A timestamp may be added to each instance of vehicle data prior to upload. Reference Figure 2 Additional processing of autonomous vehicle data by computing system 172 is described in accordance with many embodiments.

[0043] Figure 1A Each processor shown in the and various additional controllers and subsystems disclosed herein typically operate under the control of an operating system and execute or otherwise rely on various computer software applications, components, programs, objects, modules, data structures, etc., as will be described in more detail below. In addition, the various applications, components, programs, objects, modules, etc. may also be executed on one or more processors in another computer coupled to the vehicle 110A via the network 170, such as in a distributed, cloud-based, or client-server computing environment, so that the processing required to implement the computer program functions can be distributed to multiple computers and / or services on the network.

[0044] In general, routines executed to implement the various embodiments described herein, whether implemented as part of an operating system or a specific application, component, program, object, module, or sequence of instructions, or even a subset thereof, are referred to herein as "program code". The program code may include one or more instructions that reside in various memories and storage devices at various times, and when read and executed by one or more processors, performs the steps necessary to perform the steps or elements embodying various aspects of the present disclosure. In addition, while the embodiments have been and will be described below in the context of fully functional computers and systems, it should be understood that the various embodiments described herein can be distributed as program products in various forms, and that the embodiments can be implemented regardless of the specific type of computer-readable medium used to actually perform the distribution.

[0045] Examples of computer-readable media include tangible, non-transitory media such as volatile and nonvolatile memory devices, floppy disks and other removable disks, solid-state drives, hard drives, magnetic tapes, and optical disks (e.g., CD-ROMs, DVDs, etc.), and the like.

[0046] In addition, various program codes described below can be identified based on the application in which it is implemented in a specific embodiment. However, it should be understood that any specific program nomenclature below is only used for convenience, so the present disclosure should not be limited to use in any specific application that is only identified and / or implied by such nomenclature. In addition, in view of the typically endless ways in which computer programs can be organized into routines, processes, methods, modules, objects, etc., and the various ways in which program functions can be distributed among various software layers (e.g., operating systems, libraries, APIs, applications, applets, etc.) residing in typical computers, it should be understood that the present disclosure is not limited to the specific organization and distribution of program functions described herein.

[0047] Figure 1A The environment shown in 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.

[0048] 2. FM LIDAR for automotive applications

[0049] Trucks can include lidar systems (e.g. Figure 1A The vehicle control system 120, Figure 2 Lidar system in 201, Figure 3A Lidar system in 301, Figure 4 401 in the lidar system). In some embodiments, the lidar system can use frequency modulation to encode the optical signal and use optical devices to scatter the coded optical signal into free space. By detecting the frequency difference between the coded optical signal and the return signal reflected from the object, the frequency modulation (FM) lidar system can determine the position of the object and / or accurately measure the speed of the object using the Doppler effect. The FM lidar system can use continuous waves (called "FMCW lidar" or "coherent FMCW lidar") or quasi-continuous waves (called "FMQW lidar"). The lidar system can use phase modulation (PM) to encode the optical signal and use optical devices to scatter the coded optical signal into free space.

[0050] FM or phase modulation (PM) lidar systems can provide significant advantages over conventional lidar systems for automotive and / or commercial truck applications. First, in some instances, an object (e.g., a pedestrian wearing dark clothing) may have low reflectivity, reflecting only a small amount of light (e.g., 10% or less) that strikes the object back to the sensor of the FM or PM lidar system (e.g., Figure 1AIn other examples, an object (e.g., a shiny road sign) may have a high reflectivity (e.g., greater than 10%) because it reflects a large amount of light impinging on the object back toward the sensor of the FM lidar system.

[0051] Regardless of the reflectivity of the object, the FM lidar system can detect (e.g., classify, identify, find, etc.) objects at a greater distance (e.g., 2 times) than a conventional lidar system. For example, the FM lidar system can detect low-reflectivity objects at a distance of 300 meters, and high-reflectivity objects at a distance of 400 meters.

[0052] To achieve such improvements in detection capabilities, FM lidar systems can use sensors (e.g. Figure 1A Sensors 130 in). In some embodiments, these sensors can be single photon sensitive, meaning they can detect the smallest possible amount of light. While FM lidar systems can use infrared wavelengths (e.g., 950nm, 1550nm, etc.) in certain applications, it is not limited to the infrared wavelength range (e.g., near infrared: 800nm-1500nm; mid-infrared: 1500nm-5600nm; and far infrared: 5600nm-1,000,000nm). By operating an FM or PM lidar system at infrared wavelengths, the FM or PM lidar system can broadcast more intense light pulses or beams while meeting eye safety standards. Conventional lidar systems are typically insensitive to single photons and / or operate only at near infrared wavelengths, requiring them to limit their light output (and distance detection capabilities) for eye safety reasons.

[0053] Therefore, by detecting objects at a greater distance, FM lidar systems can have more time to react to unexpected obstacles. In fact, even a few milliseconds of extra time can improve safety and comfort, especially for heavy vehicles (e.g., commercial trucks) traveling at highway speeds.

[0054] Another advantage of the FM lidar system is that it provides accurate speed for each data point instantaneously. In some embodiments, the speed measurement is achieved using the Doppler effect, which shifts the frequency of the light received from the object based on at least one of the radial velocity (e.g., the direction vector between the detected object and the sensor) or the frequency of the laser signal. For example, for speeds encountered in situations on roads where the speed is less than 100 meters per second (m / s), this shift at a wavelength of 1550 nanometers (nm) is equivalent to a frequency shift of less than 130 megahertz (MHz). This frequency shift is so small that it is difficult to detect directly in the optical domain. However, by using coherent detection in an FMCW, PMCW, or FMQW lidar system, the signal can be converted to the RF domain so that the frequency shift can be calculated using various signal processing techniques. This enables the autonomous vehicle control system to process incoming data more quickly.

[0055] Instantaneous velocity calculations also make it easier for FM lidar systems to identify distant or sparse data points as objects and / or track how these objects move over time. For example, FM lidar sensors (e.g., Figure 1A A sensor 130 in the image sensor 130 may receive only a few returns (e.g., hits) for an object 300 meters away, but if those returns give velocity values ​​of interest (e.g., moving toward the vehicle at >70 mph), the FM lidar system and / or the autonomous vehicle control system can determine a corresponding weight for the probability of being associated with the object.

[0056] Faster identification and / or tracking by the FM lidar system gives the autonomous vehicle control system more time to maneuver the vehicle. Better knowledge of how fast the object is moving also allows the autonomous vehicle control system to plan a better response.

[0057] Another advantage of FM lidar systems is that they have less static than conventional lidar systems. That is, conventional lidar systems, which are designed to be more sensitive to light, typically perform poorly in bright sunlight. These systems are also susceptible to crosstalk (e.g., when sensors are confused by each other's light pulses or beams) and self-interference (e.g., when sensors are confused by their own previous light pulses or beams). To overcome these shortcomings, vehicles using conventional lidar systems typically require additional hardware, complex software, and / or more computing power to manage this "noise."

[0058] In contrast, FM lidar systems do not encounter these types of problems because each sensor is specifically designed to respond only to its own light characteristics (e.g., light beam, light wave, light pulse). If the returning light does not match the timing, frequency, and / or wavelength of the light that was originally emitted, the FM sensor can filter out (e.g., remove, ignore, etc.) that data point. As a result, FM lidar systems produce (e.g., generate, derive, etc.) more accurate data with fewer hardware or software requirements, resulting in safer and smoother driving.

[0059] Finally, FM lidar systems can be more easily scaled than conventional lidar systems. As more autonomous vehicles (e.g., cars, commercial trucks, etc.) appear on the road, vehicles driven by FM lidar systems may not have to deal with interference issues caused by sensor crosstalk. In addition, FM lidar systems use less peak power of light than conventional lidar sensors. Therefore, some or all of the optical components of FM lidar can be produced on a single chip, which produces its own benefits, as discussed in this article.

[0060] 3. Commercial Trucking

[0061] Figure 1B 1 is a block diagram illustrating an example of a system environment for an autonomous commercial truck according to some embodiments. Environment 100B includes a commercial truck 102B for hauling cargo 106B. In some embodiments, commercial truck 102B may include a vehicle configured for long-haul freight, regional freight, intermodal freight (i.e., where a road-based vehicle is used as one of multiple modes of transportation to move cargo), and / or any other road-based freight application. Commercial truck 102B may be a flatbed truck, a refrigerated truck (e.g., a refrigerated truck), a ventilated van (e.g., a dry van), a moving truck, etc. Cargo 106B may be cargo and / or agricultural products. Commercial truck 102B may include a trailer for carrying cargo 106B, such as a flatbed trailer, a low bed trailer, a step deck trailer, an expandable flatbed trailer, a side kit trailer, etc.

[0062] Environment 100B includes object 110B (in Figure 1B ), the object 110B is located within a distance of 30 meters or less from the truck.

[0063] The commercial truck 102B may include a lidar system 104B (e.g., an FM lidar system, Figure 1A The vehicle control system 120, Figure 2 Lidar system in 201, Figure 3A Lidar system in 301, Figure 4The lidar system 401 in the embodiment of the present invention is used to determine the distance to the object 110B and / or measure the speed of the object 110B. Figure 1B One lidar system 104B is shown mounted on the front of the commercial truck 102B, but the number of lidar systems and the area where the lidar systems are mounted on the commercial truck are not limited to a specific number or specific area. The commercial truck 102B may include any number of lidar systems 104B (or components thereof, such as sensors, modulators, coherent signal generators, etc.) mounted on any area (e.g., front, rear, side, top, bottom, under, and / or bottom) of the commercial truck 102B to facilitate detection of objects in any free space relative to the commercial truck 102B.

[0064] As shown, lidar system 104B in environment 100B may be configured to detect objects (eg, another vehicle, a bicycle, a tree, a street sign, a pothole, etc.) that are at a relatively close distance (eg, 30 meters or less) from commercial truck 102B.

[0065] Figure 1C 1 is a block diagram illustrating an example of a system environment for an autonomous commercial truck according to some implementations. Environment 100C includes the same components included in environment 100B (eg, commercial truck 102B, cargo 106B, lidar system 104B, etc.).

[0066] The environment 100C includes an object 110C (in Figure 1C As shown, the lidar system 104B in the environment 100C can be configured to detect objects (e.g., another vehicle, a bicycle, a tree, a street sign, a pothole, etc.) that are within a distance range of (i) greater than 30 meters and (ii) equal to or less than 150 meters from the commercial truck 102B. As shown, the lidar system 104B in the environment 100C can be configured to detect objects (e.g., another vehicle, a bicycle, a tree, a street sign, a pothole, etc.) that are a certain distance (e.g., 100 meters) from the commercial truck 102B.

[0067] Figure 1D 1 is a block diagram illustrating an example of a system environment for an autonomous commercial truck according to some implementations. Environment 100D includes the same components included in environment 100B (eg, commercial truck 102B, cargo 106B, lidar system 104B, etc.).

[0068] The environment 100D includes an object 110D (in Figure 1D As shown, the lidar system 104B in the environment 100D can be configured to detect objects (e.g., another vehicle, a bicycle, a tree, a street sign, a pothole, etc.) that are within a certain distance (e.g., 300 meters) from the commercial truck 102B.

[0069] In commercial truck transportation applications, due to the increase in weight, and therefore such vehicles require longer stopping distances, it is very important to effectively detect objects at all ranges. Due to the above advantages, FM lidar systems (e.g., FMCW and / or FMQW systems) or PM lidar systems are very suitable for commercial truck transportation applications. Therefore, commercial trucks equipped with such systems can have the ability to safely transport both personnel and goods across short or long distances, thereby not only improving the safety of commercial trucks, but also improving the safety of surrounding vehicles. In various embodiments, such FM or PM lidar systems can be used for semi-autonomous applications (wherein, commercial trucks have drivers, and some functions of commercial trucks use FM or PM lidar systems to automatically operate), or fully autonomous applications (wherein, commercial trucks are fully operated by FM or lidar systems alone or in combination with other vehicle systems).

[0070] 4. Continuous wave modulation and quasi-continuous wave modulation

[0071] In a lidar system using CW modulation, the modulator modulates the laser continuously. For example, if the modulation period is 10 seconds, the input signal is modulated throughout the entire 10 seconds. Instead, in a lidar system using quasi-CW modulation, the modulator modulates the laser to have an active portion and an inactive portion. For example, for a 10 second period, the modulator only modulates the laser for 8 seconds (sometimes called the "active portion"), but does not modulate the laser for 2 seconds (sometimes called the "inactive portion"). By doing this, the lidar system may be able to reduce power consumption for the 2 seconds because the modulator does not have to provide a continuous signal.

[0072] In frequency modulated continuous wave (FMCW) lidar for automotive applications, it may be beneficial to operate the lidar system using quasi-CW modulation, where FMCW measurement and signal processing methods are used, but the optical signal is not always in the on state (e.g., enabled, powered, transmitting, etc.). In some embodiments, the quasi-CW modulation can have a duty cycle equal to or greater than 1% and up to 50%. If the energy in the off state (e.g., disabled, powered off, etc.) can be consumed during the actual measurement time, the signal-to-noise ratio (SNR) can be improved and / or the signal processing requirements can be reduced to coherently integrate all the energy over a longer time scale.

[0073] 5. LIDAR systems for autonomous vehicles

[0074] Figure 22 is a block diagram illustrating an example environment for a lidar system for an autonomous vehicle according to some embodiments. The environment 200 includes a lidar system 201, which includes a transmit (Tx) path and a receive (Rx) path. The Tx path includes one or more Tx input / output ports ( Figure 2 ), and the Rx path includes one or more Rx input / output ports ( Figure 2 not shown).

[0075] In some embodiments, the semiconductor substrate and / or semiconductor package may include a Tx path and an Rx.In some embodiments, the semiconductor substrate and / or semiconductor package may include at least one of a silicon photonic circuit, a photonic lightwave circuit (PLC), or a III-V semiconductor circuit.

[0076] In some embodiments, the first semiconductor substrate and / or the first semiconductor package may include a Tx path, and the second semiconductor substrate and / or the second semiconductor package may include an Rx path. In some arrangements, the Rx input / output port and / or the Tx input / output port may appear (or be formed / arranged / positioned / placed) along one or more edges of one or more semiconductor substrates and / or semiconductor packages.

[0077] The environment 200 includes one or more optical devices 210 (e.g., an oscillating scanner, a one-way scanner, a Risley prism, a circulator optical device, and / or a beam collimator, etc.) coupled to the lidar system 201. In some embodiments, the one or more optical devices 210 can be coupled to the Tx path via one or more Tx input / output ports. In some embodiments, the one or more optical devices 210 can be coupled to the Rx path via one or more Rx input / output ports.

[0078] Environment 200 includes a vehicle control system 120 (eg, vehicle control system 120 of FIG. 1 ) coupled to a lidar system 201. In some implementations, vehicle control system 120 can be coupled to the Rx path via one or more Rx input / output ports.

[0079] The Tx path may include a laser source 202, a modulator 204A, a modulator 204B, and an amplifier 206. The Rx path may include a mixer 208, a detector 212, and a transimpedance amplifier (TIA) 214. Figure 2 Only a selected number of components and only one input / output channel are shown; however, environment 200 may include any number of components and / or input / output channels (in any combination) interconnected in any arrangement to facilitate combining the various functions of the lidar system to support operation of the vehicle.

[0080] The laser source 202 can be configured to generate an optical signal (or light beam) derived from (or associated with) a local oscillator (LO) signal. In some embodiments, the optical signal can have an operating wavelength equal to or substantially equal to 1550 nanometers. In some embodiments, the optical signal can have an operating wavelength between 1250 nanometers and 1400 nanometers.

[0081] The laser source 202 may be configured to provide an optical signal to a modulator 204A, which is configured to generate an optical signal based on a first radio frequency (RF) signal (in Figure 2 The modulator 204A may be configured to transmit the modulated optical signal to the amplifier 206. The amplifier 206 may be configured to amplify the modulated optical signal to generate an amplified optical signal to the optical device 210.

[0082] Optics 210 may be configured to redirect the amplified optical signal it receives from the Tx path toward an object 218 in the environment within a given field of view, may receive a return signal reflected from object 218, and provide the return signal to mixer 208 of the Rx path.

[0083] The laser source 202 can be configured to provide an LO signal to the modulator 204B, which is configured to generate an LO signal based on the second RF signal (in Figure 2 ” RF2 ) and modulates the phase and / or frequency of the LO signal using continuous wave (CW) modulation or quasi-CW modulation to generate a modulated LO signal, and sends the modulated LO signal to the mixer 208 of the Rx path.

[0084] The mixer 208 may be configured to mix (eg, combine, multiply, etc.) the modulated LO signal with the return signal to generate a down-converted signal and send the down-converted signal to the detector 212. In some arrangements, the mixer 208 may be configured to send the modulated LO signal to the detector 212.

[0085] The detector 212 may be configured to generate an electrical signal based on the down-converted signal and send the electrical signal to the TIA 214. In some arrangements, the detector 212 may be configured to generate an electrical signal based on the down-converted signal and the modulation signal.

[0086] The TIA 214 may be configured to amplify the electrical signal and send the amplified electrical signal to the vehicle control system 120 .

[0087] In some implementations, the TIA 214 can have a peak noise equivalent power (NEP) of less than 5 picowatts per square root hertz (ie, 5 x 10-12 watts per square root hertz). In some implementations, the TIA 214 can have a gain between 4 kiloohms and 25 kiloohms.

[0088] In some implementations, the detector 212 and / or the TIA 214 can have a 3 dB bandwidth between 80 kilohertz (kHz) and 450 megahertz (MHz).

[0089] Vehicle control system 120 may be configured to determine a distance to object 218 and / or measure a speed of object 218 based on one or more electrical signals it receives from the TIA.

[0090] In some implementations, modulator 204A and / or modulator 204B may have a bandwidth between 400 megahertz (MHz) and 1000 (MHz).

[0091] In some embodiments, the modulator 204A can be configured to send the first modulated light (optical) signal and the second modulated light (optical) signal to the amplifier 206. The amplifier 206 can be configured to amplify the first modulated light signal and the second modulated light signal to generate amplified light signals to the optical device 210. The optical device 210 can be configured to redirect the first modulated light signal and the second modulated light signal it receives from the Tx path to the object 218 in the environment within a given field of view, can receive the corresponding first return signal and the second return signal reflected from the object 218, and provide the first return signal and the second return signal to the mixer 208 of the Rx path. The modulator 204B can be configured to generate (1) a first modulated LO signal associated with the first modulated light signal and (2) a second modulated LO signal associated with the second modulated light signal, and send the first modulated LO signal and the second modulated LO signal to the mixer 208 of the Rx path. The mixer 208 can be configured to pair (e.g., associate, link, identify, etc.) the first return optical signal with the first modulated LO signal, and mix (e.g., combine, multiply, etc.) the first return optical signal with the first modulated LO signal to generate a first down-converted signal and send the first down-converted signal to the detector 212. Similarly, the mixer 208 can be configured to pair the second return optical signal with the second modulated LO signal, and mix the second return optical signal with the second modulated LO signal to generate a second down-converted signal and send the second down-converted signal to the detector 212. The detector 212 can be configured to generate a first electrical signal and a second electrical signal based on the first down-converted signal and the second down-converted signal, respectively. The vehicle control system 120 can be configured to determine the distance to the object 218 and / or measure the speed of the object 218 based on the first electrical signal and the second electrical signal received through the TIA 214.

[0092] 6. LIDAR system including seed modulation module

[0093] The lidar sensor system can include a modulator (e.g., a Mach-Zehnder modulator) configured to receive an optical signal from a laser source and modulate the optical signal before emitting the optical signal into the environment. The lidar sensor system can also use time multiplexing to overcome hardware requirements. For example, multiple transmit (TX) channels can be time multiplexed to share limited hardware resources (e.g., an analog-to-digital converter (ADC)). Similarly, multiple local oscillator (LO) channels can be time multiplexed to share limited hardware resources (e.g., an optical receiver / detector). In some cases, time multiplexing can be performed by an optical switch or an electronic optical switch. Since photonic integrated circuits (PICs) are widely used today to save costs, a PIC module / device is needed to efficiently perform modulation and multiplexing.

[0094] To address these issues, in some embodiments, a lidar sensor system (e.g., a FMCW or other coherent lidar sensor system) may include a seed modulation device (or seed modulation module) configured to perform modulation and multiplexing simultaneously. In some embodiments, the seed modulation device may include one or more optical amplifiers (e.g., a semiconductor optical amplifier (SOA), an erbium-doped fiber amplifier (EDFA), a fiber Raman amplifier (FRA)) for time sequencing of the amplifiers, thereby time multiplexing multiple transmit (TX) optical signals. In some embodiments, the seed modulation device may perform amplitude modulation (AM) or phase modulation using one or more SOAs. For example, the seed modulator device may generate a modulated optical signal in a range between -20dbm and 0dbm relative to the original input optical signal. The seed modulation device may forward bias or reverse bias the SOA depending on the time sequence controlled by the control circuit.

[0095] In some embodiments, the seed modulation device may include an input branch (or input optical path), a first branch (or first optical path) branching from the input optical path at one end thereof, and a second branch (or second optical path) branching from the input optical path at one end thereof. In some embodiments, the input optical path may be formed / arranged / positioned between the first optical path and the second optical path. The seed modulation device may receive a light beam (or optical signal) at the input optical path. In some embodiments, the device may receive an optical signal from a laser source at the input optical path. The first optical path may be used as a local oscillator (LO) path, and the second optical path may be used as a TX path. The device may include a plurality of TX paths branching from the second optical path at one end thereof. In some embodiments, the device may include a laser source therein.

[0096] In some embodiments, the seed modulation device may include an input port coupled to the input optical path and configured to receive an optical signal from a laser source. The device may include: an LO output port coupled / connected to the other end of the first optical path; and a plurality of TX output ports respectively coupled / connected to the other ends of the plurality of TX paths.

[0097] In some embodiments, the seed modulation device may include one or more first optical amplifiers coupled to the first optical path. The one or more first optical amplifiers may include an SOA. In some embodiments, the device may include a plurality of first phase modulators coupled to the first optical path. The plurality of first phase modulators may include an electronic optical modulator or a liquid crystal modulator. The one or more first optical amplifiers may be formed / set / positioned between the plurality of first phase modulators and the LO output port.

[0098] In some embodiments, the seed modulation device may include a plurality of second optical amplifiers respectively coupled to the plurality of TX paths. Each of the plurality of second optical amplifiers may be an SOA. In some embodiments, the device may include a plurality of second phase modulators coupled to the second optical path. The plurality of second phase modulators may include an electronic optical modulator or a liquid crystal modulator. Each of the plurality of second optical amplifiers may be formed / set / positioned between the plurality of second phase modulators and a corresponding one of the TX output ports.

[0099] In some embodiments, the seed modulation device may include a control circuit configured to generate a control signal based on an electrical signal to turn on / off each of one or more first optical amplifiers and multiple second optical amplifiers. In some embodiments, the control circuit is not included in the device, but is included in the lidar sensor system. The electrical signal may include one or more electromagnetic signals, such as one or more radio frequency (RF) signals. The control signal may indicate a time sequence for turning on / off each optical amplifier, thereby time-multiplexing the output of the optical amplifier. For example, the device may time-multiplex the output signals of multiple second optical amplifiers according to a time sequence, and activate / deactivate the output signals of one or more first optical amplifiers in synchronization with the time sequence of the multiple second optical amplifiers. In other words, the device may control multiple second optical amplifiers (e.g., SOAs) to time-multiplex TX channels by turning on / off multiple TX paths. In some embodiments, the device may output signals of multiple second optical amplifiers according to multiple corresponding time sequences that are independent of each other.

[0100] In some embodiments, the seed modulation device can turn on / off each of the plurality of second optical amplifiers with high fidelity (e.g., with a suppression ratio of 20-25 dB). In some embodiments, the seed modulation device can turn on / off each SOA by forward biasing or reverse biasing the SOA. The device can forward bias the SOA to generate emission of photons, thereby allowing the input optical signal to pass through the SOA. On the other hand, the device can reverse bias the SOA to suppress optical gain, thereby disconnecting the input optical signal. For example, if the plurality of second optical amplifiers (e.g., SOAs) are all forward biased, when the input optical path receives a 20 milliwatt (mW) beam, the beam can be divided into two 10mW beams for the first optical path and the second optical path, and further divided into a plurality of beams (e.g., 2 to 5mW beams) for each of the plurality of TX paths. On the other hand, if none of the plurality of second optical amplifiers (e.g., SOAs) are biased (whether forward biased or reverse biased), a 1mW beam can flow through each of the plurality of TX paths. If one of the SOAs is forward biased, the SOA may output a 2 to 5 mW optical beam through the corresponding TX path, whereas if the SOA is reverse biased, substantially no optical beam may be output.

[0101] In some embodiments, the seed modulation device may turn on the first optical amplifier synchronously with turning on one of the plurality of TX paths. In some embodiments, the device may turn on the first optical path synchronously with turning on any one of the plurality of TX paths. The device may turn on the first optical path by turning on the first SOA.

[0102] In some embodiments, the seed modulation device may include multiple LO paths branching from a first optical path at one end thereof. The device may include multiple third optical amplifiers coupled to the multiple LO paths, respectively. Each of the multiple third optical amplifiers may be an SOA. The device may time-multiplex the output signals of the multiple third optical amplifiers according to a time sequence. In other words, the device may control multiple third optical amplifiers (e.g., SOAs) to time-multiplex the LO channels by turning on / off the multiple LO paths. In some embodiments, the device may output the signals of the multiple third optical amplifiers according to multiple corresponding time sequences independent of each other.

[0103] In some embodiments, the seed modulation device may perform amplitude modulation (AM) or phase modulation (PM) using one or more SOAs. For example, the device may perform AM or PM on an input optical signal using multiple SOAs coupled to multiple second optical paths to generate a modulated TX signal. Similarly, the device may perform AM or PM on an input optical signal using one or more SOAs coupled to a first optical path to generate a modulated LO signal. In some embodiments, the device may perform AM or PM on an input optical signal by changing or varying the drive current of each of the multiple SOAs. The device may perform AM or PM on an input optical signal by changing or varying the amplitude of the drive current of the SOA. In some embodiments, the device may simultaneously perform AM and PM on an input optical signal by changing or varying the amplitude of the drive current of the SOA. In some embodiments, the device may perform PM on an input optical signal by changing or varying the drive current of the SOA to change the effective length of the active region of the SOA. The device may perform AM or PM on an input optical signal interleaved with multiplexing of modulated optical signals. In this way, the device can slowly modulate the input optical signal to stabilize its phase (eg, no phase drift) while simultaneously performing modulation and multiplexing.

[0104] In some embodiments, a control circuit (which may or may not be included in a seed modulation device) may be configured to change or vary a drive current of each of the one or more first optical amplifiers and the plurality of second optical amplifiers based on an electrical signal to perform AM or PM on an input optical signal. In some embodiments, the electrical signal may include one or more electromagnetic signals, such as one or more RF signals. In some embodiments, the control signal may indicate (1) a time sequence for turning on / off each optical amplifier and / or (2) a drive current of each optical amplifier.

[0105] In some embodiments, the seed modulation device may include all of its components (e.g., optical path, optical amplifier, phase modulator, etc.) formed or disposed on a single substrate. In some embodiments, the seed modulation device may be an integrated photonic device based on III-V semiconductors, wherein all of its components are made of III-V materials and formed / disposed on a single substrate made of III-V materials. The III-V material may include at least one of indium phosphide (InP), indium arsenide (InAs), or gallium and arsenide (GaAs).

[0106] In some embodiments, the seed modulation device may include at least one of a silicon photonic circuit, a photonic lightwave circuit (PLC), or a III-V semiconductor circuit, wherein all of its components (e.g., optical paths, optical amplifiers, phase modulators, etc.) are formed or arranged on a single substrate. In some embodiments, all components of the device may be formed in a single layer to form a horizontal structure of an integrated circuit. In some embodiments, the components of the device may be formed or arranged on multiple layers stacked on a single substrate to form a vertical structure of an integrated circuit. For example, the device may include a phase modulator implemented as one or more PLC modules, an optical path implemented as a silicon photonic circuit, and an SOA implemented as a III-V module, all of which are arranged / formed on a single substrate.

[0107] According to certain aspects, embodiments in the present disclosure relate to a device including an input optical path, a first optical path, a plurality of second optical paths, a first optical amplifier, a plurality of second optical amplifiers, and a control circuit. The input optical path may receive a light beam from a laser source at one end thereof. The first optical path and the plurality of second optical paths may be branched from the other end of the input optical path, respectively. The first optical amplifier may be coupled to the first optical path. The plurality of second optical amplifiers may be coupled to the plurality of second optical paths, respectively. The control circuit may selectively turn on one of the plurality of second optical amplifiers to output a modulated optical signal of the light beam. The control circuit may turn on the first optical amplifier synchronously with turning on any one of the plurality of second optical amplifiers to output a local oscillator (LO) signal.

[0108] In some embodiments, the plurality of second optical amplifiers may include a plurality of semiconductor optical amplifiers (SOAs). The control circuit may be configured to switch the plurality of SOAs on or off to time-multiplex output signals of the plurality of SOAs. The control circuit may be configured to change a drive current of one of the plurality of SOAs to perform at least one of amplitude modulation or phase modulation of the light beam.

[0109] In some embodiments, the device may include at least one of a silicon photonic circuit, a photonic lightwave circuit (PLC), or a III-V semiconductor circuit.The device may be a III-V semiconductor circuit.

[0110] In some embodiments, the first optical amplifier may be a first SOA. The control circuit may be configured to switch the first SOA on or off according to a time sequence to output a LO signal. The control circuit may be configured to change a drive current of the first SOA to perform at least one of amplitude modulation or phase modulation of the light beam.

[0111] In some embodiments, the first optical amplifier may include a plurality of third optical amplifiers. The control circuit may be configured to selectively turn on one of the plurality of third optical amplifiers to output a corresponding LO optical signal.

[0112] In some embodiments, the device may further include one or more phase modulators coupled to the second optical path. The device may further include one or more phase modulators coupled to the first optical path. The number of the one or more phase modulators coupled to the first optical path may be the same as the number of the one or more phase modulators coupled to the second optical path.

[0113] In some embodiments, the device may further include: a first output port coupled to one end of the first optical path; and a plurality of second output ports coupled to respective ends of the plurality of second optical paths. The control circuit may be configured to output the modulated optical signal of the light beam to a corresponding one of the plurality of second output ports, and to output the LO signal to the first output port.

[0114] In some embodiments, a light detection and ranging (lidar) system may include the device, a laser source configured to generate a light beam, a plurality of transmit (TX) channels, and one or more optical components. The one or more optical components may be configured to receive a first modulated optical signal and a first LO signal associated with the first modulated optical signal from the device. The one or more optical components may be configured to receive a second modulated optical signal and a second LO signal associated with the second modulated optical signal from the device. The one or more optical components may be configured to transmit the first modulated optical signal and the second modulated optical signal to the environment at a first TX channel and a second TX channel among the plurality of TX channels, respectively. The one or more optical components may be configured to receive a first return optical signal and a second return optical signal reflected from one or more objects in the environment. The one or more optical components may be configured to pair the first return optical signal and the second return optical signal with the first LO signal and the second LO signal, respectively.

[0115] According to certain aspects, embodiments of the present disclosure relate to a method for generating a modulated optical signal in a circuit. The method may include receiving, by the circuit, a light beam from a laser source at an input optical path of the circuit. The circuit may include an input optical path, a first optical path and a plurality of second optical paths branched from the input optical path, respectively, a first optical amplifier coupled to the first optical path, and a plurality of second optical amplifiers coupled to the plurality of second optical paths, respectively. The method may include receiving, by the circuit, a light beam from a laser source at the input optical path. The method may include selectively turning on, by the circuit, one of the plurality of second optical amplifiers to output a modulated optical signal of the light beam. The method may include turning on, by the circuit, the first optical amplifier in synchronization with turning on any one of the plurality of second optical amplifiers to output a local oscillator (LO) signal.

[0116] In some embodiments, the plurality of second optical amplifiers may include a plurality of semiconductor optical amplifiers (SOAs). The method may include switching one of the plurality of SOAs on or off to time-multiplex output signals of the plurality of SOAs. The method may include changing a drive current of one of the plurality of SOAs to perform at least one of amplitude modulation or phase modulation of the light beam.

[0117] Various embodiments of the present disclosure may have one or more of the following advantages and benefits.

[0118] First, embodiments of the present disclosure may provide useful techniques for efficiently performing time multiplexing of TX signals and / or LO signals using an optical amplifier (e.g., SOA) to overcome hardware requirements. For example, a seed modulation device according to some embodiments may generate multiple modulated optical signals and time multiplex the multiple modulated optical signals for multiple transmit (TX) channels and / or multiple (LO) channels. Such multiplexing may enable sharing of limited hardware resources (e.g., analog-to-digital converters (ADCs) or optical receivers / detectors).

[0119] Second, embodiments of the present disclosure may provide useful techniques for stably performing modulation (e.g., AM or PM) by changing or varying the drive current of the SOA. For example, the device may perform AM and / or PM of an input optical signal interleaved with multiplexing of the modulated optical signal. In this way, the device may slowly modulate the input optical signal to stabilize its phase (e.g., no phase drift) while performing modulation and multiplexing simultaneously.

[0120] Third, embodiments of the present disclosure may provide useful techniques for integrating components of a seed modulation device into an integrated circuit, thereby achieving significant cost savings (e.g., 5 times less than conventional implementations of circuits on a printed circuit board (PCB). For example, the seed modulation device may include at least one of a silicon photonic circuit, a photonic lightwave circuit (PLC), or a III-V semiconductor circuit, wherein all of its components (e.g., optical paths, optical amplifiers, phase modulators, etc.) are formed or disposed on a single substrate. In some embodiments, the seed modulation device may be an integrated photonic device based on a III-V semiconductor, wherein all of its components are made of III-V materials and formed / disposed on a single substrate made of III-V materials.

[0121] Figure 3A 3 is a block diagram illustrating an example of a lidar system according to some embodiments. Environment 300 includes: a lidar system 301, which includes a transmit (Tx) path and a receive (Rx) path; and one or more optical devices 310. The Tx path may include a laser source 302, a seed modulation device 350. The Tx path may include an amplifier (not shown) between the seed modulation device 350 and the one or more optical devices 310. The Rx path may include a mixer 308, a detector 312, and a transimpedance amplifier (TIA) 314. The laser source 302, the detector 312, and the TIA 314 may have similar configurations to the laser source 202, the detector 212, and the TIA 214, respectively.

[0122] The laser source 302 may be configured to provide an optical signal to a seed modulation device 350, which may be configured to modulate the amplitude, phase, and / or frequency of the optical signal based on one of the radio frequency (RF) signals 321-1, 321-2, ..., 321-N and using continuous wave (CW) modulation or quasi-CW modulation to generate corresponding modulated optical signals 341-1, 341-2, ..., 341-N, respectively. The seed modulation device 350 may be configured to time-multiplex the modulated optical signal to an amplifier (not shown). The amplifier may be configured to amplify the (multiplexed) modulated optical signal to generate an amplified optical signal to the optical device 310.

[0123] In some embodiments, the optical device 310 can (1) receive a plurality of amplified optical signals (e.g., N amplified optical signals generated based on the modulated optical signals 341-1, 341-2, ..., 341-N) via a plurality of different input channels (e.g., N different input channels), (2) transmit or steer the plurality of received amplified optical signals into the environment via a plurality of different TX channels (e.g., N different TX channels), and (3) receive a plurality of return signals reflected from one or more objects via a plurality of different RX channels (e.g., N different RX channels) and provide the return signals to the mixer 308. In some embodiments, the mixer 308 can receive the return signals via a plurality of different channels (e.g., N different channels). For example, the optical device 310 can be configured to steer the amplified optical signals it receives from the Tx path via each input channel into the environment within a given field of view, to the object 318 via the corresponding TX channel, and then receive the return signals reflected from the object 318 via the corresponding RX channel and provide the return signals to the mixer 308 of the Rx path.

[0124] The seed modulation device 350 may be configured to modulate the amplitude, phase, and / or frequency of the optical signal based on the RF signal 325 using continuous wave (CW) modulation or quasi-CW modulation to generate a modulated LO signal 345 and send the modulated LO signal to the mixer 308 of the Rx path.

[0125] In some embodiments, the seed modulation device 350 may include a control circuit 320 configured to generate a control signal based on an electrical signal (e.g., an RF signal 321-1, 321-2, ..., 321-N) to turn on / off one or more first optical amplifiers (e.g., Figure 3B 362) and a plurality of second optical amplifiers (e.g., Figure 3BIn some embodiments, the control circuit 320 is not included in the seed modulation device 350, but is included in the lidar sensor system 301. The control signal may indicate a time sequence of turning on / off each optical amplifier, thereby time-multiplexing the outputs of the optical amplifiers. For example, the device may time-multiplex the output signals of the plurality of second optical amplifiers (e.g., output optical signals 341-1, 341-2, ..., 341-N) according to the time sequence, and activate / deactivate the output signals of the one or more first optical amplifiers (e.g., output optical signals 345) in synchronization with the time sequence of the plurality of second optical amplifiers. In some embodiments, the control circuit 320 may be configured to change or vary a driving current of each of the one or more first optical amplifiers and the plurality of second optical amplifiers based on an electrical signal to perform amplitude modulation (AM) or phase modulation PM on the input optical signal. In some embodiments, the control circuit 320 may be configured to generate one or more control signals indicating (1) a time sequence of turning on / off each optical amplifier and / or (2) a driving current of each optical amplifier. More details of the seed modulation device 350 will be referred to in the following section Figure 3B and Figure 3C Give a description.

[0126] In some implementations, the mixer 308 can be configured to mix (e.g., combine, multiply, etc.) the modulated LO signal with a return signal received at the channel from the optical device 310 to generate a down-converted signal and send the down-converted signal to the detector 312. In some arrangements, the mixer 308 can be configured to send the modulated LO signal to the detector 312.

[0127] In some embodiments, the seed modulation device 350 can be configured to perform time multiplexing to send a first modulated light (optical) signal (eg, modulated optical signal 341 - 1 ) and a second modulated light (optical) signal (eg, modulated optical signal 341 - 1 ) to the amplifier ( Figure 3A ). The amplifier may be configured to amplify the first modulated optical signal and the second modulated optical signal to generate an amplified optical signal to the optical device 310. The seed modulation device 350 may be configured to (1) generate a first modulated LO signal associated with the first modulated optical signal in synchronization with generating the first modulated optical signal (e.g., generate a modulated LO signal 345 associated with the modulated optical signal 341-1 in synchronization with generating the modulated optical signal 341-1), and (2) generate a second modulated LO signal associated with the second modulated optical signal in synchronization with generating the first modulated optical signal (e.g., generate a modulated LO signal 345 associated with the modulated optical signal 341-2 in synchronization with generating the modulated optical signal 341-2).

[0128] The optical device 310 can be configured to steer the first modulated optical signal and the second modulated optical signal (at different times) it receives from the Tx path to the environment within a given field of view toward the object 318, can receive the corresponding first return signal and the second return signal reflected from the object 318, and provide the first return signal and the second return signal to the mixer 308 of the Rx path. The seed modulation device 350 can be configured to send the first modulated LO signal and the second modulated LO signal to the mixer 308 of the Rx path. The mixer 308 can be configured to pair (e.g., associate, link, identify, etc.) the first return optical signal with the first modulated LO signal, and mix (e.g., combine, multiply, etc.) the first return optical signal with the first modulated LO signal to generate a first down-converted signal and send the first down-converted signal to the detector 312. Similarly, the mixer 308 can be configured to pair the second return optical signal with the second modulated LO signal, and mix the second return optical signal with the second modulated LO signal to generate a second down-converted signal and send the second down-converted signal to the detector 312. Detector 312 may be configured to generate first and second electrical signals based on the first and second down-converted signals, respectively. Vehicle control system 120 may be configured to determine a distance to object 318 and / or measure a speed of object 318 based on the first and second electrical signals received via TIA 314 .

[0129] Figure 3B is a block diagram illustrating an example of a seed modulation device according to some embodiments.

[0130] In some embodiments, the seed modulation device 350 may include an input optical path 351, a first optical path 355 branched from the input optical path 351 at one end thereof (e.g., the left end of the first optical path 355), and a second optical path 353 branched from the input optical path at one end thereof (e.g., the left end of the second optical path 353). The input optical path 351 may be formed / arranged / positioned between the first optical path 355 and the second optical path 353. For example, Figure 3B As shown, the input optical path 351 can be formed in the middle of the device 350, and the first optical path and the second optical path can be formed in the upper and lower parts of the device 350, respectively. The seed modulation device 350 can receive a light beam (or optical signal) at the input optical path 351. The device 350 can receive a light beam (or optical signal) from a laser source (e.g., Figure 3A The optical signal of the laser source 302 in the optical path 355 is transmitted to the optical device 350. The first optical path 355 may be used as a local oscillator (LO) path, and the second optical path 353 may be used as a TX path. The device may include a plurality of TX paths (e.g., TX paths 353-1 and 353-2) branched from the second optical path 353 at one end thereof (e.g., the left end of the TX paths 353-1 and 353-2).

[0131] In some embodiments, the seed modulation device 350 may include an input port 381 coupled to the input optical path 351 and configured to receive an optical signal from a laser source. The device 350 may include: an LO output port 385 coupled / connected to the other end of the first optical path 355 (e.g., the right end of the first optical path 355); and a plurality of TX output ports (e.g., TX output ports 383-1, 383-2) respectively coupled / connected to the other ends of the plurality of TX paths.

[0132] In some embodiments, the seed modulation device 350 may include one or more first optical amplifiers (e.g., optical amplifier 362) coupled to the first optical path 355. The one or more first optical amplifiers may include an SOA (e.g., SOA 362). In some embodiments, the device may include a plurality of first phase modulators (e.g., phase modulators 361, 363) coupled to the first optical path 355. The plurality of first phase modulators may include an electronic optical modulator or a liquid crystal modulator. The one or more first optical amplifiers (e.g., optical amplifier 362) may be formed / arranged / positioned between the plurality of first phase modulators (e.g., phase modulators 361, 363) and an LO output port (e.g., LO output port 385).

[0133] In some embodiments, the seed modulation device 350 may include a plurality of second optical amplifiers (e.g., optical amplifiers 364-1, 364-2) respectively coupled to a plurality of TX paths (e.g., TX paths 353-1, 353-2). Each of the plurality of second optical amplifiers may be an SOA (e.g., SOA 364-1, 364-2). The device may include a plurality of second phase modulators (e.g., phase modulators 365, 367) coupled to the second optical path 353. The plurality of second phase modulators may include an electronic optical modulator or a liquid crystal modulator. Each of the plurality of second optical amplifiers may be formed / set / positioned between the plurality of second phase modulators and a corresponding one of the TX output ports. For example, the optical amplifier 364-1 may be formed between the phase modulators 365, 367 and the TX output port 383-1.

[0134] In some embodiments, the seed modulation device 350 may include a control circuit 320 configured to generate a control signal (e.g., a control signal 375-1, 375-2, 371) based on an electrical signal (e.g., an RF signal 321-1, 321-2, 325) to turn on / off each of the one or more first optical amplifiers and the plurality of second optical amplifiers. For example, the control circuit 320 may receive the RF signals 321-1, 321-2, 325, and generate the control signals 375-1, 375-2, 371 based on the RF signals 321-1, 321-2, 325 to turn on / off the optical amplifiers 364-1, 364-2, 364-2, respectively. The control signal may indicate a time sequence for turning on / off each optical amplifier, thereby time-multiplexing the outputs of the optical amplifiers. For example, the control circuit 320 may time-multiplex the output signals of the plurality of second optical amplifiers (e.g., optical amplifiers 364-1, 364-2) according to a time sequence, and turn on / off the output signals of one or more first optical amplifiers (e.g., optical amplifier 362) in synchronization with the time sequence of the plurality of second optical amplifiers. The control circuit 320 may turn on the first optical amplifier (e.g., optical amplifier 362) in synchronization with turning on one of the plurality of TX paths (e.g., TX paths 353-1, 353-2) via the second optical amplifier (e.g., optical amplifier 364-1, 364-2). The control circuit 320 may turn on the first optical path (e.g., optical path 355) via the first optical amplifier in synchronization with turning on any one of the plurality of TX paths (e.g., TX paths 353-1, 353-2) via the second optical amplifier. For example, the control circuit 320 may turn on / off the first optical amplifier 362 at the same time as turning on / off one of the plurality of second optical amplifiers 364-1, 364-2. In other words, the control circuit 320 may control the plurality of second optical amplifiers (eg, SOAs) to time-multiplex the TX channels by switching on / off one TX path among the plurality of TX paths 353 - 1 , 353 - 2 .

[0135] In some embodiments, the control circuit 320 can turn on / off each of the plurality of second optical amplifiers with high fidelity (e.g., with a 20-25 dB suppression ratio). The control circuit can turn on / off each SOA (e.g., SOA 362, 364-1, 364-2) by forward biasing or reverse biasing the SOA. For example, if all of the plurality of SOAs are forward biased, when the input optical path 351 receives a 20 milliwatt (mW) beam, the beam can be divided into two 10 mW beams for the first optical path 355 and the second optical path 353, and further divided into multiple beams (e.g., 2 to 5 mW beams) for the plurality of TX paths 353-1, 353-1, respectively. On the other hand, if none of the plurality of second SOAs are biased (either forward biased or reverse biased), a 1 mW beam can flow through each of the plurality of TX paths 353-1, 353-2. If one of the SOAs is forward biased, the SOA may output a 2 to 5 mW optical beam through the corresponding TX path, whereas if the SOA is reverse biased, substantially no optical beam may be output.

[0136] In some embodiments, the seed modulation device 350 can perform amplitude modulation (AM) or phase modulation (PM) using one or more SOAs (e.g., SOAs 362, 364-1, 364-2). In some embodiments, the electronic optical modulation effect can be realized in the InP SOA using different quantum well (QW) structures or without using QW (using only the intrinsic PN junction of InP). For example, the device 350 can perform AM or PM on the input optical signal (e.g., the input optical signal received from the input port 381) using multiple SOAs coupled to multiple second optical paths (e.g., TX paths 353-1, 353-2) to generate a modulated TX signal. Similarly, the device 350 can perform AM or PM on the input optical signal (e.g., the input optical signal received from the input port 381) using one or more SOAs coupled to the first optical path (e.g., optical path 355) to generate a modulated LO signal. The device 350 can perform AM or PM on the input optical signal by changing or varying the drive current of each of the multiple SOAs. The device 350 can perform AM and PM on the input optical signal at the same time by changing or varying the amplitude of the driving current of the SOA. In some embodiments, the device 350 can change or vary the driving current of the SOA (e.g., the current of the control signal 371 of the SOA 362) based on the electrical signal (e.g., the RF signal 325) to change the effective length of the active region of the SOA, thereby performing PM on the input optical signal. The device 350 can perform AM or PM (by changing the driving current of the SOA) on the input optical signal interleaved with the multiplexing of the modulated optical signal (by turning the SOA on / off). In this way, the device 350 can slowly modulate the input optical signal to stabilize its phase (e.g., no phase drift) while performing modulation and multiplexing at the same time.

[0137] In some embodiments, the control circuit 320 (which may or may not be included in the seed modulation device) can be configured to change or vary the driving current of each of the one or more first optical amplifiers and the plurality of second optical amplifiers (e.g., SOAs 364-1, 364-2, 362) based on the electrical signal (e.g., RF signals 321-1, 321-2, 325) to perform AM or PM on the input optical signal (e.g., the input signal received at the input port 381). The control circuit 320 can change or vary the driving current of each optical amplifier using a control signal indicating (1) a time sequence of turning on / off each optical amplifier and / or (2) a driving current of each optical amplifier.

[0138] exist Figure 3B , the seed modulation device 350 may include a photodiode 367, an electrical pad 373, and an optical input port 389 for a photodiode monitor.

[0139] Figure 3C 3000 according to some embodiments. The seed modulation assembly may include a housing 3010, a heat sink 3020, a cooler 3030, a seed modulation device / module / chip 350, a chip carrier 3040 accommodating the seed modulation device 350, an optical fiber array 3060, an optical fiber cable 3070, an electrical feedthrough 3080, and / or an optical fiber feedthrough 3090. The housing may be made of a nickel-cobalt-iron alloy (e.g., Kovar). The heat sink 3020 may be made of CuW (copper tungsten). The cooler 3040 may be a thermoelectric cooler (TEC). The chip carrier 3040 may be made of ceramic or plastic. The optical fiber array 3060 may be a fiber array unit (FAU). The electrical feedthrough 3080 may be configured to provide an electrical signal (e.g., an RF signal) to the seed modulation device 350. The optical fiber feedthrough 3090 may be configured to provide an optical signal (e.g., a beam from a laser source) to the seed modulation device 350.

[0140] In some embodiments, the seed modulation device 350 may include all of its components (e.g., optical paths 351, 353, 355, optical amplifiers 362, 364-1, 364-2, phase modulators 361, 363, 365, 367, etc.) formed or disposed on a single substrate. The seed modulation device 350 may be an integrated photonic device based on III-V semiconductors, wherein all of its components are made of III-V materials and formed / disposed on a single substrate made of III-V materials. The III-V material may include at least one of indium phosphide (InP), indium arsenide (InAs), or gallium and arsenide (GaAs).

[0141] In some embodiments, the seed modulation device 350 may include at least one of a silicon photonic circuit, a photonic lightwave circuit (PLC), or a III-V semiconductor circuit, wherein all components thereof (e.g., optical paths 351, 353, 355, optical amplifiers 362, 364-1, 364-2, phase modulators 361, 363, 365, 367, etc.) are formed or disposed on a single substrate. In some embodiments, all components of the device may be formed in a single layer to form a horizontal structure of an integrated circuit. In some embodiments, components of the device may be formed or disposed on multiple layers stacked on a single substrate to form a vertical structure of an integrated circuit. For example, device 350 may include phase modulators (e.g., phase modulators 361, 363, 365, 367) implemented as one or more PLC modules, optical paths (e.g., optical paths 351, 353, 355) implemented as silicon photonic circuits, and SOAs (e.g., 362, 364-1, 364-2) implemented as III-V modules, all of which are arranged / formed on a single substrate.

[0142] Figure 4 is a block diagram illustrating another example of a lidar system according to some embodiments.

[0143] Environment 400 includes: lidar system 401, which includes a transmit (Tx) path and a receive (Rx) path; and one or more optical devices 410. The Tx path may include a laser source 402, a seed modulation device 450. The Tx path may include an amplifier (not shown) between the seed modulation device 450 and the one or more optical devices 410. The Rx path may include a mixer 408, a detector 412, and a transimpedance amplifier (TIA) 414. The laser source 402, the detector 412, and the TIA 414 may have Figure 3A The laser source 302, detector 312, and TIA 314 are configured similarly to those shown in FIG.

[0144] The laser source 402 may be configured to provide an optical signal to a seed modulation device 450, which is configured to modulate the amplitude, phase and / or frequency of the optical signal based on one of the radio frequency (RF) signals 421-1, 421-2, ..., 421-N using continuous wave (CW) modulation or quasi-CW modulation to generate corresponding modulated optical signals 441-1, 441-2, ..., 441-N, respectively. The seed modulation device 450 may be configured to time-multiplex the modulated optical signal to an amplifier (not shown). The amplifier may be configured to amplify the (multiplexed) modulated optical signal to generate an amplified optical signal to the optical device 410.

[0145] In some embodiments, the optical device 410 can (1) receive a plurality of amplified optical signals (e.g., N amplified optical signals generated based on the modulated optical signals 441-1, 441-2, ..., 441-N) via a plurality of different input channels (e.g., N different input channels), (2) transmit or steer the plurality of received amplified optical signals into the environment via a plurality of different TX channels (e.g., N different TX channels), and (3) receive a plurality of return signals reflected from one or more objects via a plurality of different RX channels (e.g., N different RX channels) and provide the return signals to the mixer 408. In some embodiments, the mixer 408 can receive the return signals via a plurality of different channels (e.g., N different channels). For example, the optical device 410 can be configured to steer the amplified optical signals it receives from the Tx path via each input channel via the corresponding TX channel into the environment within a given field of view toward the object 418, and then receive the return signals reflected from the object 418 via the corresponding RX channel and provide the return signals to the mixer 408 of the Rx path.

[0146] In some embodiments, the seed modulation device 450 can be configured to modulate the amplitude, phase and / or frequency of the optical signal based on one of the radio frequency (RF) signals 425-1, 425-2, ..., 425-N and using continuous wave (CW) modulation or quasi-CW modulation to generate corresponding modulated LO signals 445-1, 445-2, ..., 445-N, respectively. The seed modulation device 450 can be configured to time-multiplex the modulated LO signal to the mixer 408 of the Rx path. In some embodiments, the mixer 408 can receive multiple modulated LO signals (e.g., N modulated LO signals 445-1, 445-2, ..., 445-N) via multiple different LO channels (e.g., N different LO channels).

[0147] In some embodiments, the seed modulation device 450 may include a second optical path (e.g., Figure 3B The device 450 may include a plurality of second optical amplifiers coupled to the plurality of TX paths, respectively. Each of the plurality of second optical amplifiers may be an SOA. The device may time-multiplex the output signals of the plurality of second optical amplifiers according to a time sequence. In other words, the device 450 may control the plurality of second optical amplifiers (e.g., SOAs) to time-multiplex the TX channels by switching on / off the plurality of TX paths.

[0148] Similarly, the seed modulation device 450 may include a first optical path (eg, Figure 3B The device may include multiple LO paths branched from the optical path 355 in the optical path 355. The device may include multiple third optical amplifiers coupled to the multiple LO paths, respectively. Each of the multiple third optical amplifiers may be an SOA. The device may time-multiplex the output signals of the multiple third optical amplifiers according to a time sequence. In other words, the device 450 may control the multiple third optical amplifiers (e.g., SOAs) to time-multiplex the LO channels by turning on / off the multiple LO paths. In some embodiments, there may be a one-to-one correspondence between (1) multiple LO paths (and multiple third optical amplifiers coupled thereto) and (2) multiple TX paths (and multiple second optical amplifiers coupled thereto).

[0149] In some embodiments, the seed modulation device 450 may include a control circuit 420 configured to generate a control signal based on an electrical signal (e.g., RF signals 421-1, 421-2, ..., 421-N) to turn on / off each of the plurality of second optical amplifiers. In some embodiments, the control circuit is not included in the seed modulation device 450, but is included in the lidar sensor system 401. The control signal may indicate a time sequence for turning on / off each second optical amplifier, thereby time-multiplexing the outputs of the optical amplifiers. For example, the device may time-multiplex the output signals of the plurality of second optical amplifiers according to the time sequence, and activate / deactivate the corresponding output signals of the plurality of third optical amplifiers (e.g., output optical signals 445-1, 445-2, ..., 445-N) in synchronization with the time sequence of the plurality of second optical amplifiers.

[0150] In some embodiments, the control circuit 420 may be configured to change or vary the driving current of each of the plurality of third optical amplifiers and the plurality of second optical amplifiers based on the electrical signal to perform amplitude modulation (AM) or phase modulation (PM) on the input optical signal. The control circuit 420 may be configured to generate one or more control signals indicating (1) a time sequence of turning on / off each optical amplifier and / or (2) a driving current of each optical amplifier.

[0151] In some implementations, the mixer 408 can be configured to mix (e.g., combine, multiply, etc.) a modulated LO signal received at a particular LO channel with a return signal received from the optical device 410 at an RX channel corresponding to the particular LO channel to generate a down-converted signal and send the down-converted signal to the detector 412. In some arrangements, the mixer 408 can be configured to send the modulated LO signal to the detector 412.

[0152] In some embodiments, the seed modulation device 450 can be configured to perform time multiplexing to send a first modulated light (optical) signal (eg, modulated optical signal 441 - 1 ) and a second modulated light (optical) signal (eg, modulated optical signal 441 - 1 ) to the amplifier ( Figure 44. The amplifier may be configured to amplify the first modulated optical signal and the second modulated optical signal to generate an amplified optical signal to the optical device 410 via a corresponding TX channel. The seed modulation device 450 may be configured to (1) generate a first modulated LO signal associated with the first modulated optical signal in synchronization with generating the first modulated optical signal (e.g., generate a modulated LO signal 445-1 associated with the modulated optical signal 441-1 in synchronization with generating the modulated optical signal 441-1), and (2) generate a second modulated LO signal associated with the second modulated optical signal in synchronization with generating the first modulated optical signal (e.g., generate a modulated LO signal 445-2 associated with the modulated optical signal 441-2 in synchronization with generating the modulated optical signal 441-2).

[0153] The optical device 410 can be configured to steer the first modulated optical signal and the second modulated optical signal (at different times) it receives from the Tx path to the environment within a given field of view to the object 418, can receive the corresponding first return signal and the second return signal reflected from the object 418, and provide the first return signal and the second return signal to the mixer 408 of the Rx path. The seed modulation device 450 can be configured to send the first modulated LO signal and the second modulated LO signal to the mixer 408 of the Rx path via the corresponding LO channel. The mixer 408 can be configured to pair (e.g., associate, link, identify, etc.) the first return optical signal with the first modulated LO signal, and mix (e.g., combine, multiply, etc.) the first return optical signal with the first modulated LO signal to generate a first down-converted signal and send the first down-converted signal to the detector 412. Similarly, the mixer 408 can be configured to pair the second return optical signal with the second modulated LO signal, and mix the second return optical signal with the second modulated LO signal to generate a second down-converted signal and send the second down-converted signal to the detector 412. Detector 412 may be configured to generate first and second electrical signals based on the first and second down-converted signals, respectively. Vehicle control system 120 may be configured to determine a distance to object 418 and / or measure a speed of object 418 based on the first and second electrical signals received via TIA 414.

[0154] Figure 5 is a diagram illustrating the use of a seed modulation device (e.g., Figure 3A , Figure 3B , Figure 3C The seed modulation device 350, or Figure 4 Flowchart of an example method for generating a modulated optical signal using a seed modulation device 350 in FIG. 1 . In some embodiments, the seed modulation device may be a circuit including the following parts: an input optical path (e.g., Figure 3B 351 in the input optical path), respectively branched from the first optical path of the input optical path (for example, Figure 3B 355) and a plurality of second optical paths (e.g., Figure 3B TX paths 353-1, 353-2 in the first optical path), coupled to a first optical amplifier (e.g., Figure 3B and optical amplifiers 362 in the optical amplifier 362) and are respectively coupled to a plurality of second optical paths (eg, Figure 3B A plurality of second optical amplifiers (eg, Figure 3B In some embodiments, the seed modulation device may include at least one of a silicon photonic circuit, a photonic lightwave circuit (PLC), or a III-V semiconductor circuit. The device may be a III-V semiconductor circuit. For example, referring to Figure 3B and Figure 3C , device 350 may include phase modulators (e.g., phase modulators 361, 363, 365, 367) implemented as one or more PLC modules, optical paths (e.g., optical paths 351, 353, 355) implemented as silicon photonic circuits, and SOAs (e.g., 362, 364-1, 364-2) implemented as III-V modules, all of which are arranged / formed on a single substrate.

[0155] In some embodiments, a first optical amplifier and a plurality of second optical amplifiers (e.g., Figure 3B The optical amplifiers 362, 364-1, 364-2 in the apparatus may include one or more semiconductor optical amplifiers (SOA). In some embodiments, the apparatus may also include a second optical path (e.g. Figure 3B One or more phase modulators (e.g. Figure 3B The device may also include a phase modulator 365, 367 coupled to the first optical path (e.g. Figure 3B One or more phase modulators (e.g. Figure 3B One or more phase modulators (e.g., phase modulators 361, 363) coupled to the first optical path Figure 3B The number of phase modulators (two phase modulators on the optical path 355 in the embodiment of the present invention) can be the same as the number of one or more phase modulators (e.g. Figure 3B In some embodiments, the device may further include: a first optical path (eg, Figure 3B A first output port (eg, Figure 3B and coupled to a plurality of second optical paths (eg, Figure 3B A plurality of second output ports (eg, Figure 3BOutput ports 383-1, 383-2 in.

[0156] Return to see Figure 5 In the example method, process 500 begins at step 520 by receiving, by a circuit (e.g., a circuit implementing seed modulation device 350) a light beam from a laser source (e.g., laser sources 202, 302, 402) at an input optical path (e.g., input optical path 351) of the circuit.

[0157] At step 540, in some embodiments, the circuit (eg, control circuit 320) may selectively turn on a plurality of second optical amplifiers (eg, Figure 3B A second optical amplifier in the optical amplifier 364-1 outputs a modulated optical signal (eg, Figure 3A The circuit can be configured to output the modulated optical signal of the light beam to a plurality of second output ports (eg, Figure 3B The output port 383-1 in the output port corresponds to a second output port.

[0158] In some embodiments, the plurality of second optical amplifiers may include a plurality of semiconductor optical amplifiers (SOAs). The control circuit may be configured to switch the plurality of SOAs on or off to time-multiplex output signals of the plurality of SOAs. The circuit may be configured to change a drive current of one of the plurality of SOAs to perform at least one of amplitude modulation (AM) or phase modulation (PM) of the light beam. For example, the circuit may be configured to generate one or more control signals (e.g., Figure 3B At least one of AM or PM of the light beam is performed using control signals 371, 375-1, 375-2 in the optical amplifier, which control signals indicate (1) the time sequence of turning on / off each optical amplifier and / or (2) the driving current of each optical amplifier.

[0159] At step 560, in some embodiments, the circuit (e.g., control circuit 320) may turn on the first optical amplifier (e.g., optical amplifier 362) in synchronization with turning on any one of the plurality of second optical amplifiers (e.g., optical amplifiers 364-1, 364-2) to output a local oscillator (LO) signal (e.g., Figure 3A The circuit can be configured to output the LO signal to a first output port (e.g., Figure 3B output port 385 in the .

[0160] In some embodiments, the first optical amplifier (e.g., optical amplifier 362) may be a first SOA. The circuit may be configured to turn on or off the first SOA according to a time sequence to output a LO signal. The circuit may be configured to change a driving current of the first SOA to perform at least one of AM or PM of the light beam.

[0161] In some embodiments, the first optical amplifier may include a plurality of third optical amplifiers. The circuit (e.g., Figure 4 The control circuit 420 in the embodiment may be configured to selectively turn on one of the plurality of third optical amplifiers to output a corresponding LO optical signal (eg, LO optical signals 445 - 1 , 445 - 2 , . . . , 445 -N).

[0162] Figure 6 is a diagram illustrating the use of a seed modulation device (e.g., FIG. 3A to FIG. 3C Devices in 350, Figure 4 450) in the device 450) to control the lidar system. In some embodiments, the lidar system (e.g., Figure 3A Lidar sensor system in 301, Figure 4 The lidar sensor system 401 in the embodiment may include a seed modulation device, a laser source configured to generate a light beam (e.g., Figure 3A Laser 302, Figure 4 402), multiple transmit (TX) channels (e.g., Figure 3A TX channels 341-1, ..., 341-N in, or Figure 4 TX channels 441-1, ..., 441-N) in the embodiment and one or more optical components (e.g., Figure 3A Optical device 310, Figure 4 Optical device 410 in.

[0163] In this example method, process 600 begins at step 610 by receiving a first modulated optical signal and a first LO signal associated with the first modulated optical signal from a seed modulation device (e.g., device 350) via one or more optical components (e.g., optical device 310). At step 620, in some embodiments, one or more optical components (e.g., optical device 310) may be configured to receive a second modulated optical signal and a second LO signal associated with the second modulated optical signal from a device (e.g., device 350).

[0164] For example, refer to Figure 3A, the seed modulation device 350 can be configured to perform time multiplexing to send the first modulated light (optical) signal (eg, the modulated optical signal 341 - 1 ) and the second modulated light (optical) signal (eg, the modulated optical signal 341 - 1 ) to the amplifier ( Figure 3A ). The amplifier may be configured to amplify the first modulated optical signal and the second modulated optical signal to generate an amplified optical signal to the optical device 310. The seed modulation device 350 may be configured to (1) generate a first modulated LO signal associated with the first modulated optical signal in synchronization with generating the first modulated optical signal (e.g., generate a modulated LO signal 345 associated with the modulated optical signal 341-1 in synchronization with generating the modulated optical signal 341-1), and (2) generate a second modulated LO signal associated with the second modulated optical signal in synchronization with generating the first modulated optical signal (e.g., generate a modulated LO signal 345 associated with the modulated optical signal 341-2 in synchronization with generating the modulated optical signal 341-2).

[0165] At step 630, in some embodiments, one or more optical components may be configured to transmit a first modulated optical signal and a second modulated optical signal to an environment at a first TX channel and a second TX channel, respectively, among a plurality of TX channels. Figure 3A , the optical device 310 can be configured to steer the first modulated optical signal and the second modulated optical signal (at different times) it receives from the Tx path to the environment within a given field of view toward the object 318,

[0166] At step 650, in some embodiments, one or more optical components may be configured to receive a first return optical signal and a second return optical signal reflected from one or more objects in the environment. Figure 3A The optical device 310 can be configured to receive corresponding first and second return signals reflected from the object 318 and provide the first and second return signals to the mixer 308 of the Rx path.

[0167] At step 650, in some embodiments, one or more optical components can be configured to pair the first return optical signal and the second return optical signal with the first LO signal and the second LO signal, respectively. Figure 3A, the seed modulation device 350 can be configured to send the first modulated LO signal and the second modulated LO signal to the mixer 308 of the Rx path. The mixer 308 can be configured to pair (e.g., associate, link, identify, etc.) the first return optical signal with the first modulated LO signal, and mix (e.g., combine, multiply, etc.) the first return optical signal with the first modulated LO signal to generate a first down-converted signal and send the first down-converted signal to the detector 312. Similarly, the mixer 308 can be configured to pair the second return optical signal with the second modulated LO signal, and mix the second return optical signal with the second modulated LO signal to generate a second down-converted signal and send the second down-converted signal to the detector 312. The detector 312 can be configured to generate a first electrical signal and a second electrical signal based on the first down-converted signal and the second down-converted signal, respectively. The vehicle control system 120 can be configured to determine the distance to the object 318 and / or measure the speed of the object 318 based on the first electrical signal and the second electrical signal received via the TIA 314.

[0168] Figure 7 is a block diagram illustrating an example of a computing system according to some implementations.

[0169] refer to Figure 7 , the illustrated example computing system 700 includes one or more processors 710 that communicate with a memory 760, at least one network interface controller 730 having a network interface port for connecting to a network (not shown), and other components (e.g., an input / output (“I / O”) component interface 750 connected to a display (not shown) and input devices (not shown) via a communication system 740 (e.g., a bus). Typically, the processor 710 will execute instructions (or computer programs) received from the memory. The illustrated processor 710 is combined with or directly connected to a cache 720. In some instances, instructions are read from the memory 760 into the cache 720 and executed by the processor 710 from the cache 720.

[0170] In more detail, processor 710 can be any logic circuit that processes instructions (e.g., instructions obtained from memory 760 or cache 720). In some embodiments, processor 710 is a microprocessor unit or a dedicated processor. Computing device 700 can be based on any processor or processor group capable of operating as described herein. Processor 710 can be a single-core or multi-core processor. Processor 710 can be a plurality of different processors.

[0171] The memory 760 may be any device suitable for storing computer-readable data. The memory 760 may be a device with fixed storage or a device for reading removable storage media. Examples include all forms of non-volatile memory, media, and memory devices, semiconductor memory devices (e.g., EPROM, EEPROM, SDRAM, and flash memory devices), magnetic disks, magneto-optical disks, and optical disks (e.g., CD ROM, DVD-ROM, or Blu-Ray® disks). The computing system 700 may have any number of memory devices as the memory 760.

[0172] Cache 720 is typically a form of computer memory that is placed close to the processor 710 to enable fast read times. In some implementations, cache 720 is part of the processor 710 or is located on the same chip as the processor 710. In some implementations, there are multiple levels of cache 720, such as L2 and L3 cache layers.

[0173] The network interface controller 730 manages data exchange via a network interface (sometimes referred to as a network interface port). The network interface controller 730 handles the physical layer and data link layer of the OSI model for network communication. In some embodiments, some of the tasks of the network interface controller are handled by one or more processors 710. In some embodiments, the network interface controller 730 is part of the processor 710. In some embodiments, the computing system 700 has multiple network interfaces controlled by a single controller 730. In some embodiments, the computing system 700 has multiple network interface controllers 730. In some embodiments, each network interface is a connection point for a physical network link (e.g., a Category 5 (cat-5) Ethernet link). In some embodiments, the network interface controller 730 supports wireless network connections, and the interface port is a wireless (e.g., radio) receiver / transmitter (e.g., for any of the IEEE 802.11 protocol, near field communication "NFC", Bluetooth, ANT, or any other wireless protocol). In some embodiments, the network interface controller 730 implements one or more network protocols, such as Ethernet. Typically, the computing device 700 exchanges data with other computing devices via a physical or wireless link through a network interface. The network interface may be linked to another device directly or via an intermediate device, such as a network device (such as a hub, bridge, switch, or router) that connects the computing device 700 to a data network such as the Internet.

[0174] The computing system 700 may include or provide an interface for one or more input or output ("I / O") devices. Input devices include, but are not limited to, keyboards, microphones, touch screens, foot pedals, sensors, MIDI devices, and pointing devices such as mice or trackballs. Output devices include, but are not limited to, video displays, speakers, refreshable Braille terminals, lights, MIDI devices, and 2D or 3D printers.

[0175] Other components may include I / O interfaces, external serial device ports, and any additional coprocessors. For example, computing system 700 may include interfaces (e.g., Universal Serial Bus (USB) interfaces) for connecting input devices, output devices, or additional storage devices (e.g., portable flash drives or external media drives). In some embodiments, computing device 700 includes additional devices, such as coprocessors, such as math coprocessors that can assist processor 710 in performing high-precision or complex calculations.

[0176] The previous description is provided to enable those skilled in the art to practice the various aspects described herein. Those skilled in the art will readily appreciate the various modifications to these aspects, and the general principles defined herein may be applied to other aspects. Therefore, the claims are not intended to be limited to the aspects shown herein, but should be given a full scope consistent with the language claims, wherein references to singular elements are not intended to mean "one and only one", unless explicitly stated, but "one or more". Unless otherwise explicitly stated, the term "some" refers to one or more. All structural and functional equivalents of the elements of the various aspects described throughout the previous description (which are known or later known to those of ordinary skill in the art) are expressly incorporated herein by reference and are intended to be included by the claims. In addition, nothing disclosed herein is intended to be exclusive to the public, whether or not this disclosure is explicitly stated in the claims. No claim element should be interpreted as a means plus function unless the phrase "means for" is used to explicitly state the element.

[0177] It should be understood that the specific order or hierarchy of blocks in the disclosed process is an example of an illustrative means. Based on design preferences, it should be understood that the specific order or hierarchy of blocks in the process can be rearranged while remaining within the scope of the above description. The accompanying method claims present elements of various blocks in an example order and are not meant to be limited to the specific order or hierarchy presented.

[0178] The description of the foregoing disclosed embodiments is intended to enable those skilled in the art to make or use the disclosed subject matter. Those skilled in the art will readily appreciate various modifications to these embodiments, and the general principles defined herein may be applied to other embodiments without departing from the spirit or scope of the foregoing description. Therefore, the foregoing description is not intended to be limited to the embodiments shown herein, but should be given the widest scope consistent with the principles and novel features disclosed herein.

[0179] The various examples shown and described are provided as examples only to illustrate various features of the claims. However, the features shown and described with respect to any given example are not necessarily limited to the associated example and may be used or combined with other examples shown and described. Furthermore, the claims are not intended to be limited by any one example.

[0180] The foregoing method descriptions and flow charts are provided as illustrative examples only and are not intended to require or imply that the blocks of the various examples must be executed in the order presented. Those skilled in the art will appreciate that the order of the blocks in the foregoing examples can be executed in any order. Words such as "thereafter," "then," "next," etc. are not intended to limit the order of the blocks; these words are only used to guide the reader through the description of the method. In addition, any reference to a claim element in the singular (e.g., using the articles "a," "an," or "the") should not be interpreted as limiting the element to the singular.

[0181] The various illustrative logic blocks, modules, circuits, and algorithm blocks described in connection with the examples disclosed herein may be implemented as electronic hardware, computer software, or a combination of the two. In order to clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and blocks have been generally described above with respect to their functionality. Whether such functions are implemented as hardware or software depends on the specific application and the design constraints imposed on the entire system. A skilled person may implement the described functions in a varying manner for each specific application, but such implementation decisions should not be interpreted as causing a deviation from the scope of the present disclosure.

[0182] The hardware for implementing the various illustrative logics, logic blocks, modules, and circuits described in connection with the examples disclosed herein may be implemented or performed with a general purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination designed to perform the functions described herein. A general purpose processor may be a microprocessor, but, in an alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, a combination of one or more microprocessors and a DSP core, or any other such configuration. Alternatively, some blocks or methods may be performed by circuits specific to a given function.

[0183] In some exemplary examples, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or codes on a non-transitory computer-readable storage medium or a non-transitory processor-readable storage medium. The blocks of the methods or algorithms disclosed herein may be embodied in a processor-executable software module, which may reside on a non-transitory computer-readable or processor-readable storage medium. A non-transitory computer-readable or processor-readable storage medium may be any storage medium that can be accessed by a computer or processor. As an example but not limited to, such a non-transitory computer-readable or processor-readable storage medium may include RAM, ROM, EEPROM, FLASH memory, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or any other medium that can be used to store the desired program code in the form of instructions or data structures and can be accessed by a computer. The disks and optical disks used herein include compact disks (CDs), laser disks, optical disks, digital versatile disks (DVDs), floppy disks, and Blu-ray disks, where disks typically reproduce data magnetically, while optical disks use lasers to reproduce data optically. The above combinations are also included within the scope of non-transitory computer-readable and processor-readable media. Furthermore, the operations of a method or algorithm may reside as one or any combination or set of codes and / or instructions on a non-transitory processor-readable storage medium and / or a computer-readable storage medium, which may be incorporated into a computer program product.

[0184] The foregoing description of the disclosed examples is provided to enable those skilled in the art to make or use the present disclosure. Those skilled in the art will readily appreciate various modifications to these examples, and the general principles defined herein may be applied to some examples without departing from the spirit or scope of the present disclosure. Therefore, the present disclosure is not intended to be limited to the examples shown herein, but is to be given the widest scope consistent with the appended claims and the principles and novel features disclosed herein.

Claims

1. A light detection and ranging (lidar) system for a vehicle, comprising: an input optical path configured to receive a light beam from a laser source; a first optical path and a plurality of second optical paths, wherein the first optical path and the plurality of second optical paths are respectively branched from the input optical path; a first optical amplifier coupled to the first optical path and configured to output a local oscillator (LO) signal; as well as A plurality of second optical amplifiers are respectively coupled to the plurality of second optical paths, and one of the plurality of second optical amplifiers is selectively turned on to modulate the light beam received through the second optical path and output a modulated optical signal of the light beam.

2. The lidar system according to claim 1, wherein: The plurality of second optical amplifiers include one or more semiconductor optical amplifiers (SOAs).

3. The lidar system according to claim 2, wherein: One of the one or more SOAs is switched on or off to perform signal modulation of the light beam.

4. The lidar system according to claim 2, wherein: One of the one or more SOAs is configured to change a driving current of the one of the one or more SOAs to perform signal modulation of the light beam.

5. The lidar system according to claim 1, wherein: The optical device includes at least one of a silicon photonic circuit, a photonic lightwave circuit (PLC), or a III-V semiconductor circuit.

6. The lidar system according to claim 1, wherein: The optical device is a III-V semiconductor circuit, and The III-V semiconductor circuit includes at least one of indium phosphide (InP), indium arsenide (InAs), or gallium and arsenide (GaAs).

7. The lidar system according to claim 1, wherein: The first optical amplifier includes a plurality of third optical amplifiers, Among them, one third optical amplifier among the plurality of third optical amplifiers is selectively turned on to output a corresponding LO optical signal.

8. The lidar system according to claim 1, wherein: The first optical amplifier includes a first semiconductor optical amplifier (SOA).

9. The lidar system according to claim 8, wherein: The first SOA is turned on or off to perform signal modulation of the light beam.

10. The lidar system according to claim 8, wherein: The first SOA is configured to vary a driving current of the first SOA to perform signal modulation of the light beam.

11. The lidar system according to claim 1, further comprising one or more phase modulators coupled to the first optical path or the second optical path, in, The one or more phase modulators are configured to perform phase modulation of the light beam.

12. The lidar system according to claim 11, further comprising: a control circuit configured to generate one or more control signals to switch the first optical amplifier and the plurality of second optical amplifiers on or off, The one or more control signals indicate a time sequence for switching on or off the plurality of second optical amplifiers.

13. The lidar system according to claim 12, wherein: The control circuit is configured to switch on or off an output signal of the first optical amplifier in synchronization with the time sequence for switching on or off the plurality of second optical amplifiers.

14. An autonomous vehicle comprising: A light detection and ranging (lidar) system, the light detection and ranging (lidar) system comprising an input optical path configured to receive a light beam from a laser source; a first optical path and a plurality of second optical paths, wherein the first optical path and the plurality of second optical paths are respectively branched from the input optical path; a first optical amplifier coupled to the first optical path and configured to output a local oscillator (LO) signal; as well as a plurality of second optical amplifiers, the plurality of second optical amplifiers being respectively coupled to the plurality of second optical paths, wherein one second optical amplifier among the plurality of second optical amplifiers is selectively turned on to modulate the light beam received through the second optical path and output a modulated optical signal of the light beam; at least one of a steering system or a braking system; as well as A vehicle controller comprising one or more processors configured to: The lidar system is operated to transmit the modulated optical signal into an environment, receive a return optical signal reflected from an object in the environment, pair the return optical signal with the LO signal to generate an electrical signal, and control at least one of the steering system or the braking system using the electrical signal.

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

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