LIDAR sensor system including seed modulation module

Abstract

A vehicle-mounted LIDAR (Light Detection and Ranging) system may include an input optical path, a first optical path, multiple second optical paths, a first optical amplifier, and multiple second optical amplifiers. The input optical path may be configured to receive a beam from a laser source. The first optical path and the multiple second optical paths may each branch off from the input optical path. The first optical amplifier may be coupled to the first optical path and configured to output a local oscillator (LO) signal. The multiple second optical amplifiers may be coupled to the multiple second optical paths, respectively, and one of the multiple second optical amplifiers may be configured to modulate a beam received via the second optical path and selectively turn on to output a modulated optical signal of the beam.

Description

Technical Field

[0001] Cross-references of related applications This application claims the benefit and priority of U.S. Application No. 17 / 888,364, filed on August 15, 2022 (currently U.S. Patent No. 11,619,716), the disclosure of which is hereby incorporated by reference in its entirety.

Background Art

[0002] Light Detection and Ranging (LIDAR) sensor systems are used in a variety of applications, from altitude measurement to imaging and collision prevention. LIDAR provides finer range resolution with a smaller beam size than conventional microwave distance measurement systems such as Radio-Wave Detection and Ranging (RADAR). Optical distance detection can be performed using various techniques, such as direct distance measurement based on the round-trip travel time of an optical pulse to an object, chirp detection based on the frequency difference between a transmitted chirped optical signal and a return signal scattered from an object, and phase-coded detection based on a series of single-frequency phase changes that are distinguishable from natural signals.

[0003] When applying such techniques, a LIDAR sensor system can include a modulator configured to receive an optical signal from a laser source and modulate the optical signal before transmitting it into the environment. The LIDAR sensor system can use time-separated I / Q processing (also called time-domain multiplexing) to overcome hardware requirements. For example, multiple transmit (TX) channels can be time-multiplexed to share limited hardware resources (e.g., receive (RX) side hardware resources). Therefore, a mechanism is needed to efficiently perform modulation and multiplexing with limited hardware resources.

Summary of the Invention

[0004] Embodiments of this disclosure relate to systems and methods for light detection and distance measurement (LIDAR) sensor systems, and more particularly to systems and methods for LIDAR sensor systems including a seed modulation module.

[0005] In some embodiments of this disclosure, the apparatus 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 beam from a laser source at one end. The first optical path and the plurality of second optical paths may branch off at 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 beam. The control circuit may be configured to turn on the first optical amplifier in synchronization with turning on one of the plurality of second optical amplifiers to output a local oscillator (LO) signal.

[0006] In some embodiments of this disclosure, an autonomous vehicle control system may include one or more processors and one or more computer-readable storage media. When performed by one or more processors, the storage media can store instructions for one or more processors to generate optical signals that are frequency-shifted by a frequency offset relative to a local oscillator (LO) signal, based on a beam generated from a laser source. One or more processors may be configured to transmit optical signals into the environment. In response to the transmission of optical signals, one or more processors may be configured to receive return optical signals that have been reflected back from objects in the environment. One or more processors may be configured to generate digital signals based on the received signals. One or more processors may be configured to digitally mix the digital signals based on the frequency offset to generate a sampled signal. One or more processors may be configured to determine the distance to an object based on the sampled signal. One or more processors may be configured to use the distance to the object to control the vehicle's operation.

[0007] In some embodiments of this disclosure, a LIDAR system may include a device, a laser source configured to generate a beam, a plurality of transmit (TX) channels, and one or more optical components. 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. 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. One or more optical components may be configured to transmit the first and second modulated optical signals, respectively, to the environment on the first and second TX channels of the plurality of TX channels. One or more optical components may be configured to receive first and second return optical signals reflected back from one or more objects in the environment. One or more optical components may be configured to pair the first and second return optical signals with the first and second LO signals, respectively.

[0008] In some embodiments of the present disclosure, a method for generating a modulated optical signal within a circuit may include the circuit receiving a beam from a laser source in the circuit's input optical path. The circuit may include an input optical path, first optical paths and a plurality of second optical paths branching from the input optical path, 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 the circuit selectively turning on one of the plurality of second optical amplifiers to output a modulated optical signal of the beam. The method may include the circuit turning on the first optical amplifier in synchronization with turning on one of the plurality of second optical amplifiers to output a local oscillator (LO) signal.

[0009] In some embodiments of the present disclosure, a vehicle LiDAR system may include an input optical path configured to receive a beam from a laser source; a first optical path and a plurality of second optical paths branching from the input optical path, respectively; 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 coupled to the plurality of second optical paths, respectively. One of the plurality of second optical amplifiers can be selectively turned on to modulate the beam received through the second optical path and to output a modulated optical signal of the beam.

[0010] In some embodiments of this disclosure, an autonomous vehicle may include a vehicle controller comprising at least one of a LiDAR system, a steering system, or a braking system, and one or more processors. The LiDAR system may include an input optical path configured to receive a beam from a laser source, a first optical path and a plurality of second optical paths branching 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 coupled to the plurality of second optical paths, respectively. One of the plurality of second optical amplifiers can be selectively turned on to modulate the beam received through the second optical path and to output a modulated optical signal of the beam. One or more processors may be configured to transmit the modulated optical signal to the environment, receive a return optical signal reflected back from objects in the environment, pair the return optical signal with the LO signal to generate an electrical signal, and operate the LiDAR system to control at least one of the steering system or a braking system using the electrical signal. [Brief explanation of the drawing]

[0011] A patent or application file must include one or more color drawings. A copy of the patent application publication containing the color drawings will be provided by the Japan Patent Office upon request and payment of the required fee.

[0012] These aspects and features of this embodiment, as well as other aspects and features, will become apparent to those skilled in the art by examining the following description of specific embodiments together with the accompanying drawings.

[0013] [Figure 1a] This is a block diagram showing an example of a system environment for an autonomous vehicle according to some embodiments.

[0014] [Figure 1b] A block diagram showing an example of a system environment for an autonomous commercial truck transport vehicle according to some embodiments.

[0015] [Figure 1c] A block diagram showing an example of a system environment for an autonomous commercial truck transport vehicle according to some embodiments.

[0016] [Figure 1d] A block diagram showing an example of a system environment for an autonomous commercial truck transport vehicle according to some embodiments.

[0017] [Figure 2] A block diagram showing an example of a LIDAR system for an autonomous vehicle according to some embodiments.

[0018] [Figure 3a] A block diagram showing an example of a LIDAR system according to some embodiments.

[0019] [Figure 3b] A block diagram showing an example of a seed modulation device according to some embodiments.

[0020] [Figure 3c] A block diagram showing an example of a seed modulation assembly according to some embodiments.

[0021] [Figure 4] A block diagram showing another example of a LIDAR system according to some embodiments.

[0022] [Figure 5] A flowchart showing an exemplary methodology for generating an optical signal modulated using a seed modulation device according to some embodiments.

[0023] [Figure 6] A flowchart showing an exemplary methodology for controlling a LIDAR system using a seed modulation device according to some embodiments.

[0024] [Figure 7] Block diagram showing an example of a computing system according to some embodiments. [Modes for carrying out the invention]

[0025] In certain embodiments, embodiments of the present disclosure relate to systems and methods for controlling a vehicle using light detection and distance measurement (LIDAR), more specifically, systems and methods for a LIDAR sensor system including a seed modulation module.

[0026] In certain embodiments, the apparatus 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 beam from a laser source at one end. The first optical path and the plurality of second optical paths may branch off at 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 beam. The control circuit may be configured to turn on the first optical amplifier in synchronization with turning on one of the plurality of second optical amplifiers to output a local oscillator (LO) signal. 1. System environment for autonomous vehicles

[0027] Figure 1a is a block diagram showing an example of a system environment for an autonomous vehicle according to some embodiments.

[0028] Referring to Figure 1a, an exemplary autonomous vehicle 110A is shown in which various technologies disclosed herein can be implemented. For example, vehicle 110A may include a powertrain 192, which includes a prime mover 194 that can receive power from an energy source 196 and power a drivetrain 198, and a control system 180, which includes directional control 182, powertrain control 184, and brake control 186. Vehicle 110A can be implemented as any number of different types of vehicles, including vehicles that can transport people and / or cargo and can operate in a variety of environments, and the aforementioned components 180-198 can vary widely based on the type of vehicle in which these components are used.

[0029] For simplicity, the embodiments discussed below focus on wheeled land vehicles such as automobiles, vans, trucks, and buses. In such embodiments, the prime mover 194 may include one or more electric motors and / or internal combustion engines (among others). Energy sources may include, for example, a fuel system (providing gasoline, diesel, hydrogen, etc.), a battery system, solar panels or other renewable energy sources and / or a fuel cell system. The drivetrain 198 may include wheels and / or tires along with a transmission and / or other optional mechanical drive components for converting the output of the prime mover 194 into vehicle motion, and may include one or more brakes configured to controllably stop or decelerate the vehicle 110A and a directional or steering component suitable for controlling the trajectory of the vehicle 110A (e.g., a rack and pinion steering linkage that allows one or more wheels of the vehicle 110A to pivot generally around a vertical axis, thereby changing the angle of the wheel's plane of rotation with respect to the vehicle's longitudinal axis). In some embodiments, a combination of powertrain and energy source can be used (for example, in electric / gas hybrid vehicles), and in some embodiments, multiple electric motors (for example, dedicated to individual wheels or axles) can be used as prime movers.

[0030] Direction control 182 may include one or more actuators and / or sensors for controlling and receiving feedback from direction or steering components to enable the vehicle 110A to follow a desired trajectory. Powertrain control 184 may be configured to control the speed and / or direction of the vehicle 110A by controlling the output of the powertrain 102, such as controlling the output of the prime mover 194 and controlling the gears of the transmission in the drivetrain 198. Brake control 116 may be configured to control one or more brakes (e.g., disc or drum brakes coupled to the wheels of the vehicle) to decelerate or stop the vehicle 110A.

[0031] Other vehicle types, including but not limited to off-road vehicles, all-terrain vehicles, or tracked vehicles, and construction equipment, may utilize different powertrains, drivetrains, energy sources, directional control, powertrain control, and brake control. Furthermore, in some embodiments, some components may be combined; for example, vehicle directional control is primarily handled by changing the output of one or more prime movers. Therefore, the embodiments described herein are not limited to specific applications of the technologies described herein in autonomous wheeled land vehicles.

[0032] Various levels of autonomous control for the vehicle 110A can be implemented in the vehicle control system 120, which may include one or more processors 122 and one or more memories 124, each processor 122 may be configured to execute program code instructions 126 stored in the memory 124. The processors may include, for example, graphics processing units (GPU(s)) and / or central processing units (CPU(s)).

[0033] Sensor 130 may include a variety of sensors suitable for collecting information from the vehicle's surrounding environment for use in controlling the vehicle's operation. For example, sensor 130 may include a radar sensor 134, a LiDAR sensor 136, and a 3D positioning sensor 138 (e.g., an accelerometer, gyroscope, magnetometer, or one of the satellite navigation systems such as GPS (Global Positioning System), GLONASS (Globalnaya Navigazionnaya Sputnikovaya Sistema, or Global Navigation Satellite System), BeiDou Navigation Satellite System (BDS), Galileo, or Compass). The 3D positioning sensor 138 can be used to determine the vehicle's position on Earth using satellite signals. Sensor 130 may include a camera 140 and / or an inertial measurement device (IMU) 142. Camera 140 may be a monographic or stereographic camera and may record still images and / or video. The IMU 142 may include a multi-gyroscope and accelerometer capable of detecting linear and rotational motion of the vehicle in three directions. One or more encoders (not shown), such as wheel encoders, can be used to monitor the rotation of one or more wheels of the vehicle 110A. Each sensor 130 can output sensor data at a variety of data rates, which may differ from the data rates of other sensors 130.

[0034] The output of sensor 130 can be provided to a set of control subsystems 150, including a position estimation subsystem 152, a planning subsystem 156, a perception subsystem 154, and a control subsystem 158. The position estimation subsystem 152 may perform functions such as precisely determining the position and orientation (also sometimes called "attitude") of vehicle 110A within its surrounding environment and generally within some reference frame. The autonomous vehicle's position can be compared to the positions of additional vehicles in the same environment as part of the generation of labeled autonomous vehicle data. The perception subsystem 154 may perform functions such as detecting, tracking, determining, and / or identifying objects in the environment surrounding vehicle 110A. Machine learning models can be used to track objects. The planning subsystem 156 may perform functions such as planning the trajectory of vehicle 110A over some time frame, given a desired destination as well as primarily static and moving objects in the environment. Machine learning models can be used to plan the vehicle trajectory. The control subsystem 158 may perform functions such as generating appropriate control signals to control various controls within the vehicle control system 120 in order to realize the planned trajectory of the vehicle 110A. A machine learning model can be used to generate one or more signals to control the autonomous vehicle in order to realize the planned trajectory.

[0035] It should be understood that the collection of components shown in Figure 1a for the vehicle control system 120 is merely illustrative. In some embodiments, individual sensors may be omitted. Additionally or alternatively, in some embodiments, multiple sensors of the type shown in Figure 1a may be used redundantly and / or to cover different areas around the vehicle, and other types of sensors may be used. Similarly, different types and / or combinations of control subsystems may be used in other embodiments. Also, although subsystems 152-158 are shown separately from processor 122 and memory 124, it should be understood that in some embodiments, some or all of subsystems 152-158 may reside in one or more memories 124 and be implemented as program code instructions 126 executed by one or more processors 122, and these subsystems 152-158 may, in some cases, be implemented using the same processor and / or memory. The subsystems can be implemented, at least in part, using various dedicated circuit logic, various processors, various field-programmable gate arrays ("FPGAs"), various application-specific integrated circuits ("ASICs"), various real-time controllers, and so on. As mentioned above, multiple subsystems may utilize circuits, processors, sensors, and / or other components. Furthermore, the various components of the vehicle control system 120 may be networked in various ways.

[0036] In some embodiments, the vehicle 110A may further include a secondary vehicle control system (not shown) that can be used as a redundant or backup control system for the vehicle 110A. The secondary vehicle control system can fully operate the autonomous vehicle 110A in the event of an unfavorable event occurring in the vehicle control system 120, but in other embodiments, the secondary vehicle control system may have only limited functions, such as controlling and shutting down the vehicle 110A in response to an unfavorable event detected by the primary vehicle control system 120. In other embodiments, the secondary vehicle control system may also be omitted.

[0037] In general, the various components shown in Figure 1a can be embodied using a number of different architectures, including various combinations of software, hardware, circuit logic, sensors, and networks. Each processor can be embodied as, for example, a microprocessor, and each memory can include not only random access memory (RAM) devices that constitute main memory, but also any auxiliary level of memory, such as cache memory, non-volatile or backup memory (e.g., programmable or flash memory), read-only memory, etc. Furthermore, each memory can be considered to include memory storage devices physically located elsewhere in the vehicle 110A, such as any cache memory within the processor, but also any storage capacity used as virtual memory, such as stored in a mass storage device or other computer controller. One or more processors or entirely different processors shown in Figure 1a can be used to embody additional functions within the vehicle 110A other than for the purpose of autonomous control, such as the operation of entertainment system control, doors, lighting, convenience functions, etc.

[0038] Furthermore, for additional storage devices, vehicle 110A may include one or more mass storage devices, such as removable disk drives, hard disk drives, direct access storage devices (DASDs), optical drives (e.g., CD drives, DVD drives, etc.), solid-state storage drives (SSDs), network-attached storage, storage area networks, and / or tape drives.

[0039] Furthermore, the vehicle 110A may include a user interface 164, such as one or more displays, touchscreens, voice and / or gesture interfaces, buttons and other haptic controls, which causes the vehicle 110A to receive a number of inputs from a user or operator and generate outputs about the user or operator. Alternatively, user input may be received via other computers or electronic devices, such as apps or web interfaces on mobile devices.

[0040] Furthermore, the vehicle 110A includes one or more network interfaces suitable for communication with one or more networks 170 (e.g., a short-range network (LAN), a wide-area network (WAN), a wireless network, and / or the Internet), such as network interface 162, enabling communication of information with other computers and electronic devices, including central services such as cloud services, thereby allowing the vehicle 110A to receive environmental and other data that can be used for autonomous control. Data collected by one or more sensors 130 can be uploaded to the computing system 172 via the network 170 for further processing. A timestamp may be added to each instance of vehicle data before uploading. Further processing of autonomous vehicle data by the computing system 172 in many embodiments is described with reference to Figure 2.

[0041] Each processor shown in Figure 1a and the various additional controllers and subsystems disclosed herein generally operate under the control of an operating system and perform, or depend on, various computer software applications, components, programs, objects, modules, data structures, etc., as will be described in detail below. Furthermore, various applications, components, programs, objects, modules, etc. may be performed on one or more processors of other computers connected to the vehicle 110A via the network 170, for example, processing required to embody the functionality of a computer program is assigned to a number of computers and / or services via the network in a distributed, cloud-based, or client-server computing environment.

[0042] Generally, routines performed to embody the various embodiments described herein, whether embodied as part of an operating system, a specific application, component, program, object, module, or sequence of instructions, or a subset thereof, are referred to herein as “program code.” Program code comprises one or more instructions residing in various memory and storage devices for various periods of time, which, when read and executed by one or more processors, perform the steps necessary to carry out the steps or elements that embody various aspects of the disclosure. While embodiments are described in the context of fully functional computers and systems, it will be understood that the various embodiments described herein can be distributed as various forms of program products, and embodiments can be embodied independently of the specific type of computer-readable medium used to carry out such distribution.

[0043] Examples of computer-readable media include, in particular, volatile and non-volatile memory devices, floppy disks and other removable disks, solid-state drives, hard disk drives, magnetic tapes, and optical discs (e.g., CD-ROMs, DVDs, etc.).

[0044] Furthermore, the various program codes described below can be identified based on the application in which they are embodied in a particular embodiment. However, any specific program naming conventions described below are used solely for convenience, and therefore, the disclosure should not be limited to use only in any specific application identified and / or implied by such naming conventions. Moreover, considering the generally endless way in which computer programs can be composed of routines, procedures, methods, modules, objects, etc., and the various ways in which program functions can be assigned between various software layers residing in a typical computer (e.g., operating systems, libraries, APIs, applications, applets, etc.), it should be understood that the disclosure is not limited to the specific structures and assignments of program functions described herein.

[0045] The environment shown in Figure 1a is not intended to limit the embodiments disclosed herein. In fact, other alternative hardware and / or software environments can be used without departing from the scope of the embodiments disclosed herein. 2. FM LiDAR for Automotive Applications

[0046] The truck may include a LiDAR system (e.g., vehicle control system 120 in Figure 1a, LiDAR system 201 in Figure 2, LiDAR system 301 in Figure 3a, LiDAR system 401 in Figure 4). In some embodiments, the LiDAR system can encode an optical signal using frequency modulation and scatter the encoded optical signal into free space using an optical system. By detecting the frequency difference between the encoded optical signal and the return signal reflected from an object, the frequency-modulated (FM) LiDAR system can determine the position of an object using the Doppler effect or precisely measure the velocity of an object. The FM LiDAR system can use continuous waves (referred to as “FMCW LiDAR” or “Coherent FMCW LiDAR”) or quasi-continuous waves (referred to as “FMQW LiDAR”). The LiDAR system can encode an optical signal using phase modulation (PM) and scatter the encoded optical signal into free space using an optical system.

[0047]

[0048]

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[0050]

[0051]

[0052] FM or phase-modulated (PM) LiDAR systems can offer significant advantages over conventional LiDAR systems for automotive and / or commercial truck transport applications. Firstly, in some cases, objects (e.g., pedestrians wearing dark clothing) may have low reflectivity, meaning only a small amount of light (e.g., less than 10%) hitting the object is reflected back to the sensor of the FM or PM LiDAR system (e.g., sensor 130 in Figure 1a). In other cases, objects (e.g., glossy road signs) may have high reflectivity (e.g., more than 10%), meaning a large amount of light hitting the object is reflected back to the sensor of the FM LiDAR system.

[0053] Regardless of the object's reflectivity, FM LiDAR systems can detect objects at greater distances (e.g., twice as far) than conventional LiDAR systems (e.g., for classification, recognition, and discovery). For example, FM LiDAR systems can detect low-reflectivity objects at distances of 300 meters or more and high-reflectivity objects at distances of 400 meters or more.

[0054] To achieve such improvements in detection capability, FM LIDAR systems can utilize sensors (e.g., sensor 130 in Figure 1a). In some embodiments, these sensors may be sensitive to single photons, meaning the sensor can detect the smallest possible amount of light. In some applications, FM LIDAR systems can utilize infrared wavelengths (e.g., 950 nm, 1550 nm, etc.), but are not limited to the infrared wavelength range (e.g., near-infrared: 800 nm to 1500 nm, mid-infrared: 1500 nm to 5600 nm, and far-infrared: 5600 nm to 1,000,000 nm). By operating FM or PM LIDAR systems at infrared wavelengths, they can broadcast stronger light pulses or beams while still meeting eye safety standards. Conventional LIDAR systems are often not sensitive to single photons and / or operate only at near-infrared wavelengths, requiring limitations on light output (and distance sensing capabilities) for eye safety.

[0055] Therefore, FM LiDAR systems can have more time to react to unexpected obstacles by detecting objects at greater distances. In fact, even an additional few milliseconds can improve stability and convenience, especially for large vehicles traveling on highways (e.g., commercial trucks).

[0056] Another advantage of FM LIDAR systems is their ability to instantly provide accurate velocity for each data point. In some embodiments, velocity measurement is achieved by utilizing the Doppler effect, which shifts the frequency of light received from an object based on at least one of either radial velocity (e.g., the direction vector between the detected object and the sensor) or the frequency of the laser signal. For example, for velocities occurring in road conditions with speeds less than 100 m / s, this shift at a 1550 nm wavelength corresponds to a frequency shift of less than 130 MHz. This frequency shift is too small to be directly detected in the optical domain. However, by utilizing coherent detection in FMCW, PMCW, or FMQW LIDAR systems, the signal can be converted to the RF domain so that the frequency shift can be calculated using various signal processing techniques. This allows autonomous vehicle control systems to process the received data more quickly.

[0057] Furthermore, instantaneous velocity calculations make it easier for FM LiDAR systems to identify distant or sparse data points as objects and / or track how these objects are moving over time. For example, an FM LiDAR sensor (e.g., sensor 130 in Figure 1a) may receive only a few returns (e.g., collisions) for objects 300m away, but if these returns provide velocity values ​​of interest (e.g., approaching a vehicle at a speed exceeding 70mph), the FM LiDAR system and / or the autonomous vehicle control system can determine individual weights for the probabilities associated with the objects.

[0058] Faster identification and / or tracking by FM LiDAR systems allows autonomous vehicle control systems to have more time to steer the vehicle. A better understanding of how fast objects are moving allows autonomous vehicle control systems to plan better reactions.

[0059] Another advantage of FM LiDAR systems is that they can be non-static compared to conventional LiDAR systems. That is, conventional LiDAR systems, designed to be more light-sensitive, typically perform poorly in bright sunlight. Such systems tend to suffer from crosstalk (e.g., when sensors are confused by each other's light pulses or beams) and self-interference (e.g., when sensors are confused by their own previous light pulses or beams). To overcome this drawback, vehicles using conventional LiDAR systems often require additional hardware, complex software, and / or more computing power to manage this "noise."

[0060] On the other hand, FM LiDAR systems do not experience this type of problem because each sensor is specifically designed to respond only to its own unique optical characteristics (e.g., light beam, light wave, light pulse). If the returned light does not match the timing, frequency, and / or wavelength of the initially transmitted light, the FM sensor can filter out (e.g., remove, ignore, etc.) that data point. This allows FM LiDAR systems to calculate (e.g., generate, derive, etc.) more accurate data with fewer hardware or software requirements, enabling smoother operation.

[0061] Finally, FM LiDAR systems are easier to scale than conventional LiDAR systems. As more autonomous vehicles (e.g., cars, commercial trucks, etc.) appear on the roads, vehicles powered by FM LiDAR systems will not have to face interference problems due to sensor crosstalk. Also, FM LiDAR systems use less peak optical power than conventional LiDAR sensors. This allows some or all of the optical components for FM LiDAR to be manufactured on a single chip, which offers unique advantages, as will be discussed herein. 3. Commercial truck transport

[0062] Figure 1b is a block diagram showing an example of a system environment for an autonomous commercial truck transport vehicle according to some embodiments. Environment 100B includes a commercial truck 102B for transporting cargo 106B. In some embodiments, the commercial truck 102B may include a vehicle configured for long-distance freight transport, regional freight transport, intermodal freight transport (i.e., a road-based vehicle is used as one of several transport modes for transporting cargo) and / or any other road-based freight transport applications. The commercial truck 102B may be a flatbed truck, a refrigerated truck (e.g., a reefer truck), a ventilated van (e.g., a dry van), a moving truck, etc. The cargo 106B may be commodities and / or agricultural products. The commercial truck 102B may include a trailer for transporting cargo 106B, such as a flatbed trailer, a lowboy trailer, a step-deck trailer, an expandable flatbed trailer, a side-kit trailer, etc.

[0063] Environment 100B includes object 110B (shown as another vehicle in Figure 1b) located within a distance of 30 meters or less from the truck.

[0064] The commercial truck 102B may include a LiDAR system 104B (e.g., the FM LiDAR system in Figure 1a, LiDAR system 201 in Figure 2, LiDAR system 301 in Figure 3a, LiDAR system 401 in Figure 4, etc.) for determining the distance to object 110B and / or measuring the speed of object 110B. Figure 1b shows one LiDAR system 104B mounted on the front of the commercial truck 102B, but the number of LiDAR systems mounted on the commercial truck and the mounting area of ​​the LiDAR systems are not limited to a specific number and specific area. The commercial truck 102B may include any number of LiDAR systems 104B (or its components such as sensors, modulators, coherent signal generators, etc.) mounted on any area of ​​the commercial truck 102B (e.g., front, rear, sides, top, bottom, underside, and / or bottom) to facilitate the detection of any free space objects relative to the commercial truck 102B.

[0065] As shown in the figure, the LIDAR system 104B in environment 100B may be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) that are at a short distance (e.g., 30 meters or less) from the commercial truck 102B.

[0066] Figure 1c is a block diagram showing an example of a system environment for an autonomous commercial truck transport vehicle according to some embodiments. Environment 100C includes the same components as those included in Environment 100B (e.g., commercial truck 102B, cargo 106B, LIDAR system 104B, etc.).

[0067] Environment 100C includes objects 110C (shown as other vehicles in Figure 1c) located within a distance range of (i) 30 meters or more and (ii) 150 meters or less from the commercial truck 102B. As shown in the illustration, the LIDAR system 104B in environment 100C may be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) located at a predetermined distance (e.g., 100 meters) from the commercial truck 102B.

[0068] Figure 1d is a block diagram showing an example of a system environment for an autonomous commercial truck transport vehicle according to some embodiments. Environment 100D includes the same components as those included in Environment 100B (e.g., commercial truck 102B, cargo 106B, LIDAR system 104B, etc.).

[0069] Environment 100D includes objects 110D (shown as other vehicles in Figure 1d) that are within a distance of 150 meters or more from the commercial truck 102B. As shown in the illustration, the LIDAR system 104B in environment 100D may be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) that are at a predetermined distance (e.g., 300 meters) from the commercial truck 102B.

[0070] In commercial truck transport applications, the increased vehicle weight necessitates longer stopping distances, making effective object detection at all ranges crucial. FM LiDAR systems (e.g., FMCW and / or FMQW systems) or PM LiDAR systems are well-suited to commercial truck transport applications due to the aforementioned advantages. Therefore, commercial trucks equipped with these systems can improve the safety of not only the truck itself but also surrounding vehicles, as they enhance the ability to safely transport both people and goods over short or long distances. In various embodiments, these FM or PM LiDAR systems can be used in semi-autonomous applications where a driver is on board the commercial truck and some functions of the truck operate autonomously using the FM or PM LiDAR system, or in fully autonomous applications where the commercial truck operates entirely by the FM or LiDAR system alone or in combination with other vehicle systems. 4. Continuous wave (CW) modulation and quasi-continuous wave (Quasi-CW) modulation

[0071] In a LiDAR system using CW modulation, the modulator continuously modulates the laser beam. For example, if the modulation period is 10 seconds, the input signal is modulated for the entire 10 seconds. Alternatively, in a LiDAR system using quasi-CW modulation, the modulator modulates the laser beam so that it has both an active and an inactive portion. For example, with a 10-second period, the modulator modulates the laser beam for only 8 seconds (also called the "active portion") and does not modulate the laser beam for 2 seconds (also called the "inactive portion"). This allows the LiDAR system to reduce power consumption by 2 seconds because the modulator does not need to provide a continuous signal.

[0072] For frequency-modulated continuous-wave (FMCW) LiDARs for automotive applications, FMCW measurement and signal processing methodologies are used, but it may be advantageous to operate the LiDAR system using quasi-CW modulation, rather than having the optical signal constantly in an on state (e.g., activation, power supply, transmission, etc.). In some embodiments, quasi-CW modulation may have a duty cycle of 1% or more and up to 50%. If energy is consumed in an off state (e.g., deactivation, power cut-off, etc.) during the actual measurement time, the signal-to-noise ratio (SNR) can be improved, and less signal processing is required, allowing all energy to be consistently integrated over a longer period of time. 5. Lidar systems for autonomous vehicles

[0073] Figure 2 is a block diagram illustrating an exemplary environment for a LiDAR system for an autonomous vehicle according to one embodiment. Environment 200 includes a LiDAR system 201 including a transmit (TX) path and a receive (RX) path. The TX path includes one or more TX input / output ports (not shown in Figure 2), and the RX path includes one or more RX input / output ports (not shown in Figure 2).

[0074] In some embodiments, the semiconductor substrate and / or semiconductor package may include TX and / RX paths. In some embodiments, the semiconductor substrate and / or semiconductor package may include at least one of silicon photonics circuitry, PLC (photonic lightwave circuit), or III-V semiconductor circuitry.

[0075] 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 configurations, the RX input / output ports and / or the TX input / output ports may be located along one or more edges of one or more semiconductor substrates and / or semiconductor packages.

[0076] The environment 200 includes one or more optical systems 210 (e.g., a vibratory scanner, a unidirectional scanner, a Risley prism, a circulator optic, and / or a beam collimator) coupled to the LIDAR system 201. In some embodiments, one or more optical systems 210 may be coupled to the TX path via one or more TX input / output ports. In some embodiments, one or more optical systems 210 may be coupled to the RX path via one or more RX input / output ports.

[0077] The environment 200 includes a vehicle control system (e.g., vehicle control system 120 in Figure 1) coupled to the LIDAR system 201. In some embodiments, the vehicle control system 120 may be coupled to the RX path via one or more RX input / output ports.

[0078] The TX path may include a laser source 202, modulator 204A, modulator 204B, and amplifier 206. The RX path may include a mixer 208, detector 212, and transimpedance amplifier (TIA) 214. Although Figure 2 shows only a selected number of components and one input / output channel, the environment 200 may include any number of components and / or input / output channels (in any combination) interconnected in any array to facilitate various combinations of functions of the LIDAR system to support the operation of the vehicle.

[0079] The laser source 202 may be configured to generate an optical signal (or beam) derived from (or associated with) a local oscillator (LO) signal. In some embodiments, the optical signal may have the same or substantially the same operating wavelength as 1550 nanometers. In some embodiments, the optical signal may have an operating wavelength between 1250 nanometers and 1400 nanometers.

[0080] The laser source 202 may be configured to provide an optical signal to the modulator 204A, which may be configured to modulate the phase and / or frequency of the optical signal based on a first radio frequency (RF) signal (indicated as "RF1" in Figure 2) to produce a modulated optical signal using continuous wave (CW) modulation or quasi-CW modulation. The modulator 204A may be configured to transmit the modulated optical signal to the amplifier 206, which may be configured to amplify the modulated optical signal to produce an amplified optical signal to the optical system 210.

[0081] The optical system 210 is configured to direct the amplified optical signal received from the TX path toward the object 218 in the environment within a given field of view, receive the return signal reflected back from the object 218, and provide the return signal to the mixer 208 in the RX path.

[0082] The laser source 202 may be configured to provide an LO signal to the modulator 204B, which may be configured to modulate the phase and / or frequency of the LO signal using continuous wave (CW) modulation or quasi-CW modulation based on a second RF signal (indicated as "RF2" in Figure 2) to generate a modulated LO signal, and to transmit the modulated LO signal to the mixer 208 in the RX path.

[0083] The mixer 208 may be configured to mix (e.g., combine, multiply, etc.) the modulated LO signal with the return signal to generate a down-converted signal, and to transmit the down-converted signal to the detector 212. In some configurations, the mixer 208 may be configured to transmit the modulated LO signal to the detector 212.

[0084] The detector 212 may be configured to generate an electrical signal based on the down-converted signal and transmit the electrical signal to the TIA 214. In some configurations, the detector 212 may be configured to generate an electrical signal based on the down-converted signal and the modulated signal.

[0085] The TIA214 can be configured to amplify electrical signals and transmit the amplified electrical signals to the vehicle control system 120.

[0086] In some embodiments, the TIA214 has a power output of 5 picowatts per square root hertz (i.e., 5 × 10⁻¹⁶ picowatts per square root hertz). -12 It may have a peak noise-equivalent power (NEP) of less than watts. In some embodiments, the TIA214 may have a gain between 4 kiloohms and 25 kiloohms.

[0087] In some embodiments, the detector 212 and / or TIA 214 may have a 3-decibel bandwidth between 80 kilohertz (kHz) and 450 megahertz (MHz).

[0088] The vehicle control system 120 may be configured to determine the distance to object 218 and / or measure the speed of object 218 based on one or more electrical signals received from the TIA.

[0089] In some embodiments, modulators 204A and / or modulators 204B may have bandwidths between 400 MHz and 1000 MHz.

[0090] In some embodiments, modulator 204A may be configured to transmit a first modulated optical signal and a second modulated optical signal to amplifier 206. Amplifier 206 may be configured to amplify the first and second modulated optical signals to produce an amplified optical signal to optical system 210. Optical system 210 is configured to steer the first and second modulated optical signals received from the TX path toward an object 218 in a given field of view environment, receive the corresponding first and second return signals reflected back from object 218, and provide the first and second return signals to mixer 208 on the RX path. Modulator 204B may be configured to generate (1) a first modulated LO signal associated with the first modulated optical signal and (2) a second modulated LO signal associated with the second modulated optical signal, and transmit the first and second modulated LO signals to mixer 208 on the RX path. Mixer 208 may be configured to pair (e.g., connect, link, identify, etc.) a first return optical signal with a first modulated LO signal, 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 transmit the first down-converted signal to detector 212. Similarly, mixer 208 may be configured to pair a second return optical signal with a second modulated LO signal, mix the second return optical signal with the second modulated LO signal to generate a second down-converted signal, and transmit the second down-converted signal to detector 212. Detector 212 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 the distance to object 218 and / or measure the speed of object 218 based on the first and second electrical signals received via TIA 214. 6. Lidar system including seed modulation module

[0091] A LiDAR sensor system may 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 transmitting it to the environment. Furthermore, LiDAR sensor systems may utilize temporal multiplexing to overcome hardware requirements. For example, multiple transmit (TX) channels can be temporally multiplexed to share limited hardware resources (e.g., analog-to-digital converters (ADCs)). Similarly, multiple local oscillator (LO) channels can be temporally multiplexed to share limited hardware resources (e.g., photo receivers / detectors). In some cases, temporal multiplexing can be performed by optical or electro-optical switches. Currently, photonic integrated circuits (PICs) are widely used for cost reduction, requiring PIC modules / devices for efficient modulation and multiplexing.

[0092] To address this issue, in some embodiments, a LiDAR sensor system (e.g., an FMCW or other coherent LiDAR sensor system) may include a seed modulator (or seed modulation module) configured to perform modulation and multiplexing simultaneously. In some embodiments, the seed modulator may include one or more optical amplifiers (e.g., a Semiconductor Optical Amplifier (SOA), an Erbium-Doped Fiber Amplifier (EDFA), or a Fiber Raman Amplifier (FRA)) for time sequencing of the amplifiers, thereby enabling the time multiplexing of multiple transmit (TX) optical signals. In some embodiments, the seed modulator may perform amplitude modulation (AM) or phase modulation using one or more SOAs. For example, the seed modulator may generate an optical signal modulated in the range of -20 dBm to 0 dBm relative to the original input optical signal. The seed modulator can bias the SOAs forward or backward depending on the time sequence controlled by the control circuit.

[0093] In some embodiments, the seed modulator may include an input leg (or input optical path), a first leg (or first optical path) branching off from the input optical path at one end, and a second leg (or second optical path) branching off from the input optical path at one end. In some embodiments, the input optical path may be formed / arranged / located between the first and second optical paths. The seed modulator may receive an optical beam (or optical signal) in the input optical path. In some embodiments, the device may receive an optical signal from a laser source in the input optical path. The first optical path may function as a local oscillator (LO) path, and the second optical path may function as a TX path. The device may include a plurality of TX paths branching off from the second optical path at one end. In some embodiments, the device may include a laser source.

[0094] In some embodiments, the seed modulator may include an input port coupled to an input optical path and configured to receive an optical signal from a laser source. The device may also include an LO output port coupled to the other end of a first optical path and a plurality of TX output ports, each coupled to the other end of a plurality of TX paths.

[0095] In some embodiments, the seed modulator may include one or more first optical amplifiers coupled to the first optical path. The one or more first optical amplifiers may include SOA. In some embodiments, the apparatus may include a plurality of first phase modulators coupled to the first optical path. The plurality of first phase modulators may include electro-optic modulators or liquid crystal modulators. The one or more first optical amplifiers may be formed / arranged / located between the plurality of first phase modulators and the LO output port.

[0096] In some embodiments, the seed modulator may include a plurality of second optical amplifiers coupled to a plurality of TX paths, each of which may be an SOA. In some embodiments, the apparatus may include a plurality of second phase modulators coupled to the second optical paths, each of which may be an electro-optic modulator or a liquid crystal modulator. Each of the plurality of second optical amplifiers may be formed / arranged / located between the plurality of second phase modulators and a corresponding one of the TX output ports.

[0097] In some embodiments, the seed modulator may include a control circuit configured to generate control signals to turn on or off one or more first optical amplifiers and a plurality of second optical amplifiers based on an electrical signal. In some embodiments, the control circuit is not included in the apparatus but is included in the LIDAR sensor system. The electrical signal may include one or more electromagnetic signals, for example, one or more radio frequency (RF) signals. The control signals indicate a time sequence for turning each optical amplifier on or off, thereby enabling the temporal multiplexing of the optical amplifier outputs. For example, the apparatus can temporally multiplex the output signals of a plurality of 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 sequences of the plurality of second optical amplifiers. That is, the seed modulator can control a plurality of second optical amplifiers (e.g., SOAs) to temporally multiplex a TX channel by turning a plurality of TX paths on or off. In some embodiments, the apparatus can output signals from a plurality of second optical amplifiers according to a plurality of separate time sequences independent of each other.

[0098] In some embodiments, the seed modulator can turn each of the multiple second optical amplifiers on or off with high fidelity (e.g., a 20-25 dB suppression ratio). In some embodiments, the seed modulator can turn each SOA on or off by biasing the SOA forward or backward. The device can forward-bias the SOA to generate photon emission, thereby allowing the input optical signal to pass through the SOA. Conversely, the device can reverse-bias the SOA to suppress optical gain, thereby turning off the input optical signal. For example, if all of the multiple second optical amplifiers (e.g., SOA) are forward-biased, when the input optical path receives a 20 milliwatt (mW) optical beam, the optical beam may be split into two 10 mW beams for the first and second optical paths, and further split into multiple 2-5 mW beams for the multiple TX paths. On the other hand, if none of the multiple second optical amplifiers (e.g., SOAs) are biased (forward or reverse), a 1mW optical beam can flow through each of the multiple TX paths. If one of the SOAs is forward-biased, that SOA may output a 2-5mW optical beam through its corresponding TX path, but if it is reverse-biased, it may not output an optical beam at all.

[0099] In some embodiments, the seed modulator can turn on the first optical amplifier in synchronization with turning on one of the multiple TX paths. In some embodiments, the device can turn on the first optical path in synchronization with turning on any of the multiple TX paths. The device can turn on the first optical path by turning on the first SOA.

[0100] In some embodiments, the seed modulation device may include a plurality of LO paths branching off from the first optical path at one end of the first optical path. The device may include a plurality of third optical amplifiers coupled to each of the plurality of LO paths. Each of the plurality of third optical amplifiers may be an SOA. The device can temporally multiplex the output signals of the plurality of third optical amplifiers according to a time sequence. That is, the device can control the plurality of third optical amplifiers (e.g., SOAs) to temporally multiplex the LO channels by turning the plurality of LO paths on or off. In some embodiments, the device can output signals from the plurality of third optical amplifiers according to a plurality of separate time sequences that are independent of each other.

[0101] In some embodiments, a 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 of an input optical signal to generate a modulated TX signal using multiple SOAs coupled to multiple second optical paths. Similarly, the device may perform AM or PM of an input optical signal to generate a modulated LO signal using one or more SOAs coupled to a first optical path. In some embodiments, the device may perform AM or PM of an input optical signal by changing or varying the drive current of each of the multiple SOAs. The device may perform AM or PM of an input optical signal by changing or varying the amplitude of the drive current of the SOAs. In some embodiments, the device may perform AM and PM of an input optical signal simultaneously by changing or varying the amplitude of the drive current of the SOAs. In some embodiments, the device may perform PM of an input optical signal by changing or varying the drive current of the SOAs to change the effective length of the active region of the SOAs. The device may perform AM or PM of an input optical signal in conjunction with the multiplexing of modulated optical signals. In this way, the device can slowly modulate the input optical signal to stabilize its phase (e.g., without phase shift), and can perform modulation and multiplexing simultaneously.

[0102] In some embodiments, a control circuit (which may or may not be included in a seed modulator) may be configured to perform AM or PM of an input optical signal by changing or varying the respective drive currents of one or more first optical amplifiers and a plurality of second optical amplifiers based on an electrical signal. In some embodiments, the electrical signal may include one or more electromagnetic signals, for example, one or more RF signals. In some embodiments, the control signal may indicate (1) a time sequence for turning each optical amplifier on or off and / or (2) the drive current of each optical amplifier.

[0103] In some embodiments, the seed modulator may include all components (e.g., optical paths, optical amplifiers, phase modulators, etc.) formed or arranged on a single substrate. In some embodiments, the seed modulator may be a III-V semiconductor-based integrated photonic in which all components are made of III-V material and formed / arranged on a single substrate made of III-V material. The III-V material may include at least one of indium phosphide (InP), indium monoarsenide (InAs), or gallium and arsenide (GaAs).

[0104] In some embodiments, a seed modulator may include at least one of a silicon photonic circuit, a PLC (Photonic Lightwave Circuit), or a III-V semiconductor circuit, where all 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 the horizontal structure of an integrated circuit. In some embodiments, the components of the device may be formed or arranged in multiple layers stacked on a single substrate to form the 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.

[0105] In certain embodiments, embodiments of the present disclosure relate to an apparatus comprising 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 can receive a beam from a laser source at one end of the input optical path. The first optical path and the plurality of second optical paths can each branch at the other end of the input optical path. The first optical amplifier can be coupled to the first optical path. The plurality of second optical amplifiers can each be coupled to the plurality of second optical paths. The control circuit can selectively turn on one of the plurality of second optical amplifiers to output a modulated optical signal of the beam. The control circuit can turn on the first optical amplifier in synchronization with turning on one of the plurality of second optical amplifiers to output a local oscillator (LO) signal.

[0106] 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 turn the plurality of SOAs on or off in order to temporally multiplex the output signals of the plurality of SOAs. The control circuit may be configured to change the drive current of one of the plurality of SOAs in order to perform at least one of amplitude modulation or phase modulation of the beam.

[0107] In some embodiments, the device may include at least one of a silicon photonics circuit, a PLC, or a III-V semiconductor circuit. The device may be a III-V semiconductor circuit.

[0108] In some embodiments, the first optical amplifier may be a first SOA. The control circuit may be configured to turn the first SOA on or off to output an LO signal according to a time sequence. The control circuit may be configured to change the drive current of the first SOA to perform at least one of amplitude modulation or phase modulation of the beam.

[0109] 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 the corresponding LO optical signal.

[0110] In some embodiments, the apparatus may further include one or more phase modulators coupled to a second optical path. The apparatus may further include one or more phase modulators coupled to a first optical path. The number of one or more phase modulators coupled to the first optical path may be the same as the number of one or more phase modulators coupled to the second optical path.

[0111] In some embodiments, the device may further include a first output port coupled to one end of a first optical path and a plurality of second output ports coupled to one end of each of a plurality of second optical paths. The control circuit may be configured to output the modulated optical signal of the beam to one of the plurality of second output ports, and to output the LO signal to the first output port.

[0112] In some embodiments, the LIDAR system may include a device, a laser source configured to generate a beam, a plurality of transmit (TX) channels, and one or more optical components. 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. 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. One or more optical components may be configured to transmit the first and second modulated optical signals to the environment on the first and second TX channels of the plurality of TX channels, respectively. One or more optical components may be configured to receive first and second return optical signals reflected from one or more objects in the environment. One or more optical components may be configured to pair the first and second return optical signals with the first and second LO signals, respectively.

[0113] In certain embodiments, embodiments of the present disclosure relate to a method for generating a modulated optical signal within a circuit. The method may include the circuit receiving a beam from a laser source through 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 branching from the input optical path, 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 the circuit selectively turning on one of the plurality of second optical amplifiers to output a modulated optical signal of the beam. The method may include turning on the first optical amplifier in synchronization with the circuit turning on one of the plurality of second optical amplifiers to output a local oscillator (LO) signal.

[0114] In some embodiments, the plurality of second optical amplifiers may include a plurality of semiconductor optical amplifiers (SOAs). This method may include turning one of the plurality of SOAs on or off in order to temporally multiplex the output signals of the plurality of SOAs. This method may include changing the drive current of one of the plurality of SOAs to perform at least one of amplitude modulation or phase modulation of the beam.

[0115] Various embodiments of this disclosure have one or more of the following advantages and benefits:

[0116] Firstly, embodiments of the present disclosure may provide useful techniques for efficiently performing temporal multiplexing of TX and / or LO signals using optical amplifiers (e.g., SOAs) to overcome hardware requirements. For example, seed modulators according to some embodiments can generate multiple modulated optical signals and temporally multiplex multiple modulated optical signals for multiple transmit (TX) channels and / or multiple (LO) channels. This multiplexing enables the sharing of limited hardware resources (e.g., analog-to-digital converters (ADCs) or optical receivers / detectors).

[0117] Secondly, embodiments of the present disclosure may provide useful techniques for stable 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 the input optical signal in conjunction with the multiplexing of the modulated optical signal. In this way, the device may slowly modulate the input optical signal to stabilize the phase of the input optical signal (e.g., without phase shift) and perform modulation and multiplexing simultaneously.

[0118] Thirdly, embodiments of the present disclosure may provide useful techniques for integrating seed modulator components into integrated circuits, thereby achieving significant cost reductions (e.g., five times less cost than conventional embodiments with circuits on printed circuit boards (PCBs)). For example, a seed modulator may include at least one of a silicon photonic circuit, a PLC, or a III-V semiconductor circuit, in which all components (e.g., optical paths, optical amplifiers, phase modulators, etc.) are formed or arranged on a single substrate. In some embodiments, the seed modulator may be a III-V semiconductor-based integrated photonic device in which all components are made of III-V material and formed / arranged on a single substrate made of III-V material.

[0119] Figure 3a is a block diagram showing an example of a LiDAR system according to some embodiments. The environment 300 includes a LiDAR system 301 including a transmit (TX) path and a receive (RX) path, and one or more optical systems 310. The TX path may include a laser source 302 and a seed modulator 350. The TX path may include an amplifier (not shown) between the seed modulator 350 and one or more optical systems 310. The RX path may include a mixer 308, a detector 312, and a transimpedance amplifier (TIA) 314. The laser source 302, detector 312, and TIA 314 may have configurations similar to those of the laser source 202, detector 212, and TIA 214, respectively.

[0120] The laser source 302 may be configured to provide an optical signal to the seed modulator 350, which may be configured to modulate the amplitude, phase, and / or frequency of the optical signal using continuous wave (CW) modulation or quasi-CW modulation based on one of the radio frequency (RF) signals 321-1, 321-2, ..., 321-N to generate the corresponding modulated optical signals 341-1, 341-2, ..., 341-N. The seed modulator 350 may be configured to temporally multiplex the modulated optical signal to an amplifier (not shown). The amplifier may be configured to amplify the (multiplexed) modulated optical signal to generate the amplified optical signal to the optical system 310.

[0121] In some embodiments, the optical system 310 may (1) receive a plurality of amplified optical signals (e.g., N amplified optical signals generated based on 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 received amplified optical signals to the environment via a plurality of different TX channels (e.g., N different TX channels), and (3) receive a plurality of return signals reflected back 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 may receive the return signals via a plurality of different channels (e.g., N different channels). For example, the optical system 310 may be configured to steer the amplified optical signals received from the TX path via each input channel toward an object 318 in the environment within a given field of view via the corresponding TX channel, receive the return signals reflected back from the object 318 via the corresponding RX channel, and provide the return signals to the mixer 308 on the RX path.

[0122] The seed modulation device 350 may be configured to modulate the amplitude, phase, and / or frequency of the optical signal using continuous wave (CW) modulation or quasi-CW modulation based on the RF signal 325 to generate a modulated LO signal 345, and to transmit the modulated LO signal to the mixer 308 in the RX path.

[0123] In some embodiments, the seed modulator 350 may include a control circuit 320 configured to generate control signals to turn on or off one or more first optical amplifiers (e.g., optical amplifier 362 in Figure 3b) and a plurality of second optical amplifiers (e.g., optical amplifiers 364-1, 364-2 in Figure 3b) based on electrical signals (e.g., RF signals 321-1, 321-2, ..., 321-N). In some embodiments, the control circuit is not included in the seed modulator 350 but is included in the LIDAR sensor system 301. The control signals may indicate a time sequence for turning each optical amplifier on / off, thereby allowing the outputs of the optical amplifiers to be temporally multiplexed. For example, the device may temporally multiplex the output signals of a plurality of second optical amplifiers (e.g., output optical signals 341-1, 341-2, ..., 341-N) according to the time sequence, and activate / deactivate one or more output signals of the first optical amplifiers (e.g., output optical signal 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 the respective drive currents of one or more first optical amplifiers and a plurality of second optical amplifiers based on an electrical signal in order to perform amplitude modulation (AM) or phase modulation (PM) of 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 for turning each optical amplifier on or off and / or (2) the drive current of each optical amplifier. Details of the seed modulator 350 are described in the following sections with reference to Figures 3b and 3c.

[0124] In some embodiments, the mixer 308 may be configured to mix (e.g., combine, multiply, etc.) the modulated LO signal with the return signal received from the optical system 310 in the channel in order to generate a down-converted signal and transmit the down-converted signal to the detector 312. In some configurations, the mixer 308 may be configured to transmit the modulated LO signal to the detector 312.

[0125] In some embodiments, the seed modulator 350 may be configured to perform time multiplexing to transmit a first modulated optical signal (e.g., modulated optical signal 341-1) and a second modulated optical signal (e.g., modulated optical signal 341-1) to an amplifier (not shown in Figure 3a). The amplifier may be configured to amplify the first and second modulated optical signals to produce an amplified optical signal for the optical system 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 the generation of the first modulated optical signal (for example, generating a modulated LO signal 345 associated with modulated optical signal 341-1 in synchronization with the generation of modulated optical signal 341-1), and (2) generate a second modulated LO signal associated with the second modulated optical signal in synchronization with the generation of the first modulated optical signal (for example, generating a modulated LO signal 345 associated with modulated optical signal 341-2 in synchronization with the generation of modulated optical signal 341-2).

[0126] The optical system 310 is configured to direct first and second modulated optical signals received from the TX path toward object 318 in the environment within a given field of view (at different times), receive corresponding first and second return signals reflected back from object 318, and provide the first and second return signals to mixer 308 on the RX path. Seed modulator 350 may be configured to transmit first and second modulated LO signals to mixer 308 on the RX path. Mixer 308 may be configured to pair (e.g., connect, link, identify, etc.) the first return optical signal with the first modulated LO signal, 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 transmit the first down-converted signal to detector 312. Similarly, mixer 308 may be configured to pair the second return optical signal with the second modulated LO signal, mix the second return optical signal with the second modulated LO signal to generate a second downconverted signal, and transmit the second downconverted signal to detector 312. Detector 312 may be configured to generate first and second electrical signals, respectively, based on the first and second downconverted signals. Vehicle control system 120 may be configured to determine the distance to object 318 and / or measure the speed of object 318 based on the first and second electrical signals received via TIA 314.

[0127] Figure 3b is a block diagram showing an example of a seed modulation device according to some embodiments.

[0128] In some embodiments, the seed modulator 350 may include an input optical path 351, a first optical path 355 branching off from the input optical path 351 at one end (e.g., the left end of the first optical path 355), and a second optical path 353 branching off from the input optical path 351 at one end (e.g., the left end of the second optical path 353). The input optical path 351 may be formed / arranged / located between the first optical path 355 and the second optical path 353. For example, as shown in Figure 3b, the input optical path 351 may be formed in the middle portion of the apparatus 350, and the first and second optical paths may be formed in the upper and lower portions of the apparatus 350, respectively. The seed modulator 350 may receive an optical beam (or optical signal) in the input optical path 351. The apparatus 350 may receive an optical signal from a laser source (e.g., a laser source 302 in Figure 3a) in the input optical path. The first optical path 355 can function as a local oscillator (LO) path, and the second optical path 353 can function as a TX path. The device may include multiple TX paths (e.g., TX paths 353-1 and 353-2) branching off from the second optical path 353 at one end of the second optical path 353 (e.g., the left end of TX paths 353-1 and 353-2).

[0129] 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 also include an LO output port 385 coupled 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) coupled to the other ends of a plurality of TX paths, respectively.

[0130] In some embodiments, the seed modulator 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 apparatus 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 electro-optic modulators or liquid crystal modulators. The one or more first optical amplifiers (e.g., optical amplifier 362) may be formed / arranged / located between the plurality of first phase modulators (e.g., phase modulators 361, 363) and the LO output port (e.g., LO output port 385).

[0131] In some embodiments, the seed modulator 350 may include a plurality of second optical amplifiers (e.g., optical amplifiers 364-1, 364-2) each 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 apparatus 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 electro-optic modulators or liquid crystal modulators. Each of the plurality of second optical amplifiers may be formed / arranged / located between the plurality of second phase modulators and a corresponding one of the TX output ports. For example, optical amplifier 364-1 may be formed between phase modulators 365, 367 and TX output port 383-1.

[0132] In some embodiments, the seed modulator 350 may include a control circuit 320 configured to generate control signals (e.g., control signals 375-1, 375-2, 371) for turning on or off one or more first optical amplifiers and a plurality of second optical amplifiers, based on electrical signals (e.g., RF signals 321-1, 321-2, 325). For example, the control circuit 320 may receive RF signals 321-1, 321-2, 325 and generate control signals 375-1, 375-2, 371 for turning on or off each of the optical amplifiers 364-1, 364-2, 362, based on the RF signals 321-1, 321-2, 325. The control signals may indicate a time sequence for turning each optical amplifier on or off, thereby enabling the temporal multiplexing of the optical amplifier outputs. For example, the control circuit 320 can temporally multiplex the output signals of multiple second optical amplifiers (e.g., optical amplifiers 364-1, 364-2) according to their time sequence, and turn on or off the output signals of one or more first optical amplifiers (e.g., optical amplifier 362) in synchronization with the time sequence of the multiple second optical amplifiers. The control circuit 320 can turn on the first optical amplifier (e.g., optical amplifier 362) in synchronization with turning on one of multiple TX paths (e.g., TX paths 353-1, 353-2) via the second optical amplifiers (e.g., optical amplifiers 364-1, 364-2). The control circuit 320 can turn on the first optical path (e.g., optical path 355) via the first optical amplifier in synchronization with turning on one of the multiple TX paths (e.g., TX paths 353-1, 353-2) via the second optical amplifiers. For example, the control circuit 320 can turn on or off one of the multiple second optical amplifiers 364-1, 364-2, and also turn on or off the first optical amplifier 362. That is, the control circuit 320 can control multiple second optical amplifiers (e.g., SOA) to temporally multiplex the TX channel by turning on or off multiple TX paths 353-1, 353-2.

[0133] In some embodiments, the control circuit 320 can turn each of the multiple second optical amplifiers on or off with high fidelity (e.g., a suppression ratio of 20-25 dB). The control circuit can also turn each SOA (e.g., SOA 362, 364-1, 364-2) on or off by biasing the SOA in the forward or reverse direction. For example, if all of the multiple SOA are forward-biased, when the input optical path 351 receives a 20 milliwatt (mW) optical beam, the optical beam may be split into two 10 mW optical beams for the first and second optical paths 355, 353, and further split into multiple optical beams (e.g., 2-5 mW) for each of the multiple TX paths 353-1, 353-1. On the other hand, if none of the multiple second SOA are biased (either forward or reverse), a 1 mW optical beam may flow through each of the multiple TX paths 353-1, 353-2. If one of the SOAs is forward-biased, that SOA can output a 2-5mW optical beam through the corresponding TX path, but if that SOA is reverse-biased, it can effectively not output an optical beam.

[0134] In some embodiments, the seed modulation device 350 may 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 electro-optical modulation effect can be implemented using different quantum well (QW) structures or in InPSOA without using QWs (using only the intrinsic PN junctions of InP). For example, the device 350 may perform AM or PM on an input optical signal (e.g., an input optical signal received from input port 381) to generate a modulated TX signal using multiple SOAs coupled to multiple second optical paths (e.g., TX paths 353-1, 353-2). Similarly, the device 350 may perform AM or PM on an input optical signal (e.g., an input optical signal received from input port 381) to generate a modulated LO signal using one or more SOAs coupled to a first optical path (e.g., optical path 355). The device 350 can perform AM or PM of 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 of the input optical signal simultaneously by changing or varying the amplitude of the drive current of the SOAs. In some embodiments, the device 350 can change or vary the drive current of the SOAs (e.g., the current of the control signal 371 for SOA 362) based on an electrical signal (e.g., an RF signal 325) to change the effective length of the active region of the SOAs, thereby performing PM of the input optical signal. The device 350 can perform AM or PM of the input optical signal (by changing the drive current of the SOAs) in conjunction with multiplexing of the modulated optical signal (by turning the SOAs on or off). In this way, the device 350 can slowly modulate the input optical signal to stabilize the phase of the input optical signal (e.g., without phase shift), and can perform modulation and multiplexing simultaneously.

[0135] In some embodiments, the control circuit 320 (which may or may not be included in the seed modulator) may be configured to change or vary the respective drive currents of one or more first optical amplifiers and a plurality of second optical amplifiers (e.g., SOA364-1, 364-2, 362) based on an electrical signal (e.g., RF signals 321-1, 321-2, 325) to perform AM or PM of an input optical signal (e.g., an input signal received at input port 381). The control circuit 320 may change or vary the drive currents of each optical amplifier using (1) a time sequence for turning each optical amplifier on or off and / or (2) a control signal indicating the drive current of each optical amplifier.

[0136] In Figure 3b, the seed modulator 350 may include a photodiode 367, an electrical pad 373, and an optical input port 389 for photodiode monitoring.

[0137] Figure 3c is a block diagram showing an example of a seed modulation assembly 3000 according to some embodiments. The seed modulation assembly may include a housing 3010, a heat sink 3020, a cooler 3030, a seed modulator / module / chip 350, a chip carrier 3040 housing the seed modulator 350, an optical fiber array 3060, an optical fiber cable 3070, an electric 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 tungsten copper (CuW). The cooler 3040 may be a thermo-electric cooler (TEC). The chip carrier 3040 may be made of ceramic or plastic. The optical fiber array 3060 may be an optical fiber array unit (FAU). The electrical feedthrough 3080 may be configured to provide an electrical signal (e.g., an RF signal) to the seed modulator 350. The optical fiber feedthrough 3090 may be configured to provide an optical signal (e.g., an optical beam from a laser source) to the seed modulator 350.

[0138] In some embodiments, the seed modulator 350 may include all components formed or arranged on a single substrate (e.g., optical paths 351, 353, 355), optical amplifiers 362, 364-1, 364-2, phase modulators 361, 363, 365, 367, etc.). The seed modulator 350 may be a III-V semiconductor-based integrated photonic device in which all components are made of III-V material and formed / arranged on a single substrate made of III-V material. The III-V material may include at least one of indium phosphide (InP), indium arsenide (InAs), or gallium arsenide (GaAs).

[0139] In some embodiments, the seed modulator 350 may include at least one of a silicon photonics circuit, PLC, or III-V semiconductor circuit in which all components (e.g., optical paths 351, 353, 355, optical amplifiers 362, 364-1, 364-2, phase modulators 361, 363, 365, 367, etc.) are formed or arranged on a single substrate. In some embodiments, all components of the apparatus may be formed in a single layer to form a horizontal structure of an integrated circuit. In some embodiments, the components of the apparatus may be formed or arranged in multiple layers stacked on a single substrate to form a vertical structure of an integrated circuit. For example, the device 350 may include one or more phase modulators implemented as PLC modules (e.g., phase modulators 361, 363, 365, 367), optical paths implemented as silicon photonic circuits (e.g., optical paths 351, 353, 355), and SOAs implemented as III-V modules (e.g., 362, 364-1, 364-2), all of which may be arranged / formed on a single substrate.

[0140] Figure 4 is a block diagram showing yet another example of a LIDAR system according to some embodiments.

[0141] Environment 400 includes a LiDAR system 401 including a transmit (TX) path and a receive (RX) path, and one or more optical systems 410. The TX path may include a laser source 402 and a seed modulator 450. The TX path may include an amplifier (not shown) between the seed modulator 450 and one or more optical systems 410. The RX path may include a mixer 408, a detector 412, and a transimpedance amplifier (TIA) 414. The laser source 402, detector 412, and TIA 414 may have configurations similar to those of the laser source 302, detector 312, and TIA 314 shown in Figure 3a, respectively.

[0142] The laser source 402 may be configured to supply an optical signal to a seed modulator 450 configured to modulate the amplitude, phase, and / or frequency of the optical signal using continuous wave (CW) modulation or quasi-CW modulation based on one of the radio frequency (RF) signals 421-1, 421-2, ..., 421-N to generate corresponding modulated optical signals 441-1, 441-2, ..., 441-N, respectively. The seed modulator 450 may be configured to temporally 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 for the optical system.

[0143] In some embodiments, the optical system 410 may (1) receive a plurality of amplified optical signals (e.g., N amplified optical signals generated based on 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 received amplified optical signals to the environment via a plurality of different TX channels (e.g., N different TX channels), and (3) receive a plurality of return signals reflected back 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 may receive the return signals via a plurality of different channels (e.g., N different channels). For example, the optical system 410 may be configured to steer the amplified optical signals received from the TX path via each input channel toward an object 418 in the environment within a given field of view via the corresponding TX channel, receive the return signals reflected back from the object 418 via the corresponding RX channel, and provide the return signals to the mixer 408 on the RX path.

[0144] In some embodiments, the seed modulator 450 may be configured to modulate the amplitude, phase, and / or frequency of an optical signal using continuous wave (CW) modulation or quasi-CW modulation based on one of the radio frequency (RF) signals 425-1, 425-2, ..., 425-N to generate corresponding modulated LO signals 445-1, 445-2, ..., 445-N, respectively. The seed modulator 450 may be configured to temporally multiplex the modulated LO signals to a mixer 408 in the RX path. In some embodiments, the mixer 408 may 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).

[0145] In some embodiments, the seed modulator 450 may include a plurality of TX paths branching off from the second optical path at one end of the second optical path (e.g., optical path 353 in Figure 3b). The device 450 may include a plurality of second optical amplifiers coupled to each of the plurality of TX paths. Each of the plurality of second optical amplifiers may be an SOA. The device can temporally multiplex the output signals of the plurality of second optical amplifiers according to the time sequence. That is, the device 450 can control the plurality of second optical amplifiers (e.g., SOAs) to temporally multiplex the TX channel by turning the plurality of TX paths on or off.

[0146] Similarly, the seed modulator 450 may include a plurality of LO paths branching off from the first optical path at one end of the first optical path (e.g., optical path 355 in Figure 3b). The device may include a plurality of third optical amplifiers coupled to each of the plurality of LO paths. Each of the plurality of third optical amplifiers may be an SOA. The device can temporally multiplex the output signals of the plurality of third optical amplifiers according to the time sequence. That is, the device 450 can control the plurality of third optical amplifiers (e.g., SOAs) to temporally multiplex the LO channels by turning the plurality of LO paths on or off. In some embodiments, there may be a one-to-one correspondence between (1) a plurality of LO paths (and a plurality of third optical amplifiers coupled thereto) and (2) a plurality of TX paths (and a plurality of second optical amplifiers coupled thereto).

[0147] In some embodiments, the seed modulator 450 may include a control circuit 420 configured to generate control signals for turning each of the multiple second optical amplifiers on or off based on electrical signals (e.g., RF signals 421-1, 421-2, ..., 421-N). In some embodiments, the control circuit is not included in the seed modulator 450 but is included in the LIDAR sensor system 401. The control signals may indicate a time sequence for turning each of the second optical amplifiers on or off, thereby enabling the output of the optical amplifiers to be temporally multiplexed. For example, the device may temporally multiplex the output signals of the multiple second optical amplifiers according to the time sequence and activate / deactivate the corresponding output signals of the multiple third optical amplifiers (e.g., output optical signals 445-1, 445-2, ..., 445-N) in synchronization with the time sequence of the multiple second optical amplifiers.

[0148] In some embodiments, the control circuit 420 may be configured to change or vary the respective drive currents of a plurality of third optical amplifiers and a plurality of second optical amplifiers based on an electrical signal in order to perform amplitude modulation (AM) or phase modulation (PM) of the input optical signal. The control circuit 420 may be configured to generate one or more control signals indicating (1) a time sequence for turning each optical amplifier on or off and / or (2) the drive current of each optical amplifier.

[0149] In some embodiments, the mixer 408 may be configured to mix (e.g., combine, multiply, etc.) a modulated LO signal received on a specific LO channel with a return signal received from the optical system 410 on the RX channel corresponding to the specific LO channel to generate a down-converted signal, and to transmit the down-converted signal to the detector 412. In some configurations, the mixer 408 may be configured to transmit a modulated LO signal to the detector 412.

[0150] In some embodiments, the seed modulator 450 may be configured to perform temporal multiplexing to transmit a first modulated optical signal (e.g., modulated optical signal 441-1) and a second modulated optical signal (e.g., modulated optical signal 441-1) to an amplifier (not shown in Figure 4). The amplifier may be configured to amplify the first and second modulated optical signals to produce amplified optical signals for the optical system 410 via individual TX channels. The seed modulator 450 may be configured to (1) generate a first modulated LO signal associated with the first modulated optical signal in synchronization with the generation of the first modulated optical signal (for example, generate a modulated LO signal 445-1 associated with the modulated optical signal 441-1 in synchronization with the generation of the modulated optical signal 441-1), and (2) generate a second modulated LO signal associated with the second modulated optical signal in synchronization with the generation of the first modulated optical signal (for example, generate a modulated LO signal 445-2 associated with the modulated optical signal 441-2 in synchronization with the generation of the modulated optical signal 441-2).

[0151] The optical system 410 is configured to direct first and second modulated optical signals received from the TX path toward object 418 in the environment within a given field of view (at different time zones), receive corresponding first and second return signals reflected back from object 418, and provide the first and second return signals to mixer 408 on the RX path. Seed modulator 450 may be configured to transmit first and second modulated LO signals to mixer 408 on the RX path via individual LO channels. Mixer 408 may be configured to pair (e.g., connect, link, identify, etc.) the first return optical signal with the first modulated LO signal, mix (e.g., combine, multiply, etc.) the first return optical signal with the first modulated LO signal to produce a first down-converted signal, and transmit the first down-converted signal to detector 412. Similarly, mixer 408 may be configured to pair the second return optical signal with the second modulated LO signal, mix the second return optical signal with the second modulated LO signal to generate a second downconverted signal, and transmit the second downconverted signal to detector 412. Detector 412 may be configured to generate first and second electrical signals, respectively, based on the first and second downconverted signals. Vehicle control system 120 may be configured to determine the distance to object 418 and / or measure the speed of object 418 based on the first and second electrical signals received via TIA 414.

[0152] Figure 5 is a flowchart illustrating an exemplary methodology for generating a modulated optical signal using a seed modulator according to some embodiments (e.g., seed modulator 350 in Figures 3a, 3b, 3c, or 4). In some embodiments, the seed modulator may be a circuit comprising an input optical path (e.g., input optical path 351 in Figure 3b), first optical paths branching from the input optical path (e.g., optical path 355 in Figure 3b), and a plurality of second optical paths (e.g., TX paths 353-1, 353-2 in Figure 3b), a first optical amplifier (e.g., optical amplifier 362 in Figure 3b), and a plurality of second optical amplifiers (e.g., optical amplifiers 364-1, 364-2 in Figure 3b) coupled to the plurality of second optical paths (e.g., TX paths 353-1, 353-2 in Figure 3b). In some embodiments, the seed modulator may include at least one of a silicon photonics circuit, a PLC, or a III-V semiconductor circuit. The device may be a III-V semiconductor circuit. For example, referring to Figures 3b and 3c, the apparatus 350 may include one or more phase modulators implemented as PLC modules (e.g., phase modulators 361, 363, 365, 367), optical paths implemented as silicon photonic circuits (e.g., optical paths 351, 353, 355), and SOAs implemented as III-V modules (e.g., 362, 364-1, 364-2), all of which may be arranged / formed on a single substrate.

[0153] In some embodiments, the first optical amplifier and a plurality of second optical amplifiers (e.g., optical amplifiers 362, 364-1, 364-2 in Figure 3b) may include one or more semiconductor optical amplifiers (SOAs). In some embodiments, the apparatus may further include one or more phase modulators (e.g., phase modulators 365, 367 in Figure 3b) coupled to a second optical path (e.g., optical path 353 in Figure 3b). The apparatus may further include one or more phase modulators (e.g., phase modulators 361, 363 in Figure 3b) coupled to the first optical path (e.g., optical path 355 in Figure 3b). The number of one or more phase modulators coupled to the first optical path (e.g., two phase modulators on optical path 355 in Figure 3b) may be the same as the number of one or more phase modulators coupled to the second optical path (e.g., two phase modulators on optical path 353 in Figure 3b). In some embodiments, the device may further include a first output port (e.g., output port 385 in Figure 3b) coupled to one end of a first optical path (e.g., optical path 355 in Figure 3b) and a plurality of second output ports (e.g., output ports 383-1, 383-2 in Figure 3b) coupled to one end of each of a plurality of second optical paths (e.g., optical paths 353-1, 353-2 in Figure 3b).

[0154] Referring again to Figure 5, in this exemplary methodology, process 500 is initiated in step 520 by a circuit (e.g., a circuit implementing the seed modulator 350) receiving a beam from a laser source (e.g., laser sources 202, 302, 402) in the circuit's input optical path (e.g., input optical path 351).

[0155] In step 540, in some embodiments, the circuit (e.g., control circuit 320) can selectively turn on one of a plurality of second optical amplifiers (e.g., optical amplifier 364-1 in Figure 3b) to output the modulated optical signal of the beam (e.g., modulated optical signal 341-1 in Figure 3a). The circuit may be configured to output the modulated optical signal of the beam to one of a plurality of second output ports, corresponding to one (e.g., output port 383-1 in Figure 3b).

[0156] In some embodiments, the plurality of second optical amplifiers may include a plurality of semiconductor optical amplifiers (SOA). The control circuit may be configured to turn the plurality of SOA on or off in order to temporally multiplex the output signals of the plurality of SOA. The circuit may be configured to change the drive current of one of the plurality of SOA in order to perform at least one of amplitude modulation (AM) or phase modulation (PM) of the beam. For example, the circuit may be configured to perform at least one of AM or PM of the beam by generating one or more control signals (e.g., control signals 371, 375-1, 375-2 in Figure 3b) indicating (1) a time sequence for turning each optical amplifier on or off and / or (2) the drive current of each optical amplifier.

[0157] In step 560, in some embodiments, the circuit (e.g., control circuit 320) may turn on a first optical amplifier (e.g., optical amplifier 362) in synchronization with turning on one of a plurality of second optical amplifiers (e.g., optical amplifiers 364-1, 364-2) to output a local oscillator (LO) signal (e.g., LO signal 345 in Figure 3a). The circuit may be configured to output the LO signal to a first output port (e.g., output port 385 in Figure 3b).

[0158] In some embodiments, the first optical amplifier (e.g., optical amplifier 362) may be a first SOA. The circuit may be configured to turn the first SOA on or off to output an LO signal depending on the time sequence. The circuit may be configured to change the drive current of the first SOA to perform at least one of AM or PM of the beam.

[0159] In some embodiments, the first optical amplifier may include a plurality of third optical amplifiers. The circuit (e.g., control circuit 420 in Figure 4) may be configured to selectively turn on one of the plurality of third optical amplifiers to output the corresponding LO optical signals (e.g., LO optical signals 445-1, 445-2, ..., 445-N).

[0160] Figure 6 is a flowchart illustrating an exemplary methodology for controlling a LiDAR system using a seed modulation device according to some embodiments (e.g., device 350 in Figures 3a-3c, device 450 in Figure 4). In some embodiments, the LiDAR system (e.g., LiDAR sensor system 301 in Figure 3a, LiDAR sensor system 401 in Figure 4) may include a seed modulation device, a laser source configured to generate a beam (e.g., laser 302 in Figure 3a, laser 402 in Figure 4), multiple transmit (TX) channels (e.g., TX channels 341-1, ..., 341-N in Figure 3a, or TX channels 441-1, ..., 441-N in Figure 4), and one or more optical components (e.g., optical system 310 in Figure 3a, optical system 410 in Figure 4).

[0161] In this exemplary methodology, process 600 is initiated in step 610 by one or more optical components (e.g., optical system 310) receiving a first modulated optical signal and a first LO signal associated with the first modulated optical signal from a seed modulator (e.g., apparatus 350). In step 620, in some embodiments, one or more optical components (e.g., optical system 310) may be configured to receive a second modulated optical signal and a second LO signal associated with the second modulated optical signal from an apparatus (e.g., apparatus 350).

[0162] For example, referring to Figure 3a, the seed modulator 350 may be configured to perform temporal multiplexing to transmit a first modulated optical signal (e.g., modulated optical signal 341-1) and a second modulated optical signal (e.g., modulated optical signal 341-1) to an amplifier (not shown in Figure 3a). The amplifier may be configured to amplify the first and second modulated optical signals to produce an amplified optical signal for the optical system 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 the generation of the first modulated optical signal (for example, generate a modulated LO signal 345 associated with modulated optical signal 341-1 in synchronization with the generation of modulated optical signal 341-1), and (2) generate a second modulated LO signal associated with the second modulated optical signal in synchronization with the generation of the first modulated optical signal (for example, generate a modulated LO signal 345 associated with modulated optical signal 341-2 in synchronization with the generation of modulated optical signal 341-2).

[0163] In step 630, in some embodiments, one or more optical components may be configured to transmit first and second modulated optical signals to the environment on a first and second TX channel, respectively, of a plurality of TX channels. For example, referring to Figure 3a, the optical system 310 may be configured to direct the first and second modulated optical signals received from the TX path toward an object 318 in the environment within a given field of view at different times.

[0164] In step 650, in some embodiments, one or more optical components may be configured to receive first and second return optical signals reflected back from one or more objects in the environment. For example, referring to Figure 3a, optical component 310 may be configured to receive the corresponding first and second return signals reflected back from object 318 and to provide the first and second return signals to mixer 308 in the RX path.

[0165] In step 650, in some embodiments, one or more optical components may be configured to pair the first and second return optical signals with the first and second LO signals, respectively. For example, referring to Figure 3a, the seed modulator 350 may be configured to transmit the first and second modulated LO signals to a mixer 308 in the RX path. The mixer 308 may be configured to pair (e.g., connect, link, identify, etc.) the first return optical signal with the first modulated LO signal, mix (e.g., combine, multiply, etc.) the first return optical signal with the first modulated LO signal to produce a first down-converted signal, and transmit the first down-converted signal to the detector 312. Similarly, the mixer 308 may be configured to pair the second return optical signal with the second modulated LO signal, mix the second return optical signal with the second modulated LO signal to produce a second down-converted signal, and transmit the second down-converted signal to the detector 312. The detector 312 may be configured to generate first and second electrical signals, respectively, based on first and second downconverted signals. The vehicle control system 120 may be configured to determine the distance to object 318 and / or measure the speed of object 318 based on the first and second electrical signals received via TIA 314.

[0166] Figure 7 is a block diagram showing an example of a computing system according to some embodiments.

[0167] Referring to Figure 7, the illustrated computing system 700 includes one or more processors 710 that communicate with memory 760 via a communication system 740 (e.g., a bus), at least one network interface controller 730 having a network interface port for connecting to a network (not shown), and an input / output ("I / O") component interface 750 connected to other components, such as a display (not shown) and an input device (not shown). Generally, the processors 710 execute instructions (or computer programs) received from memory. The illustrated processors 710 either integrate with or are directly connected to a cache memory 720. In some cases, instructions are read from memory 760 into the cache memory 720 and executed by the processors 710 from the cache memory 720.

[0168] More specifically, the processor 710 may be any logic circuit that processes instructions, for example, instructions fetched from memory 760 or cache 720. In some embodiments, the processor 710 is a microprocessor unit or a special-purpose processor. The computing device 700 may be based on any processor or set of processors capable of operating as described herein. The processor 710 may be a single-core or multi-core processor. The processor 710 may be multiple different processors.

[0169] Memory 760 can be any device suitable for storing computer-readable data. Memory 760 can be a device for reading fixed storage or 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 memory 760.

[0170] Cache memory 720 is a type of computer memory typically located close to the processor 710 for fast read times. In some embodiments, the cache memory 720 may be part of the processor 710 or located on the same chip as the processor. In some embodiments, multiple levels of cache 720 (e.g., L2 and L3 cache layers) may be present.

[0171] The network interface controller 730 manages data exchange via network interfaces (also called network interface ports). The network interface controller 730 handles the physical and data link layers 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 Cat-5 Ethernet link). In some embodiments, the network interface controller 730 supports wireless network connectivity, and the interface ports are wireless (e.g., radio) receivers / transmitters (e.g., for any of the following wireless protocols: IEEE 802.11 protocol, Near Field Communication "NFC", Bluetooth, ANT, or other wireless protocols). In some embodiments, the network interface controller 730 implements one or more network protocols, such as Ethernet. Generally, the computing device 700 exchanges data with other computing devices via a physical link or wireless link through a network interface. The network interface may be directly connected to the other device or connected to the other device via an intermediary device (e.g., 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.

[0172] The computing system 700 may include or provide an interface to one or more input or output ("I / O") devices. Input devices include, but are not limited to, keyboards, microphones, touchscreens, 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, lighting, MIDI devices, and 2D or 3D printers.

[0173] Other components may include I / O interfaces, external serial device ports, and optional additional coprocessors. For example, the computing system 700 may include interfaces (e.g., a Universal Serial Bus (USB) interface) for connecting input devices, output devices, or additional memory devices (e.g., portable flash drives or external media drives). In some embodiments, the computing device 700 may include additional devices such as coprocessors (e.g., a Math Co-Processor that can support the processor 710 for high-precision or complex calculations).

[0174] The foregoing description is provided to enable a person skilled in the art to implement the various embodiments described herein. Various modifications to these embodiments are readily apparent to a person skilled in the art, and the general principles defined herein are applicable to other embodiments. Therefore, the claims are not limited to the embodiments described herein, but should be recognized as encompassing the entire scope consistent with the language of the claims, and references to a single component mean "one or more" and not "one and only" unless otherwise specified. Unless otherwise specified, the term "part" means one or more. All structural and functional equivalents of elements of the various embodiments described herein, known to a person skilled in the art, or to become known later, are expressly incorporated herein by reference and intended to be included in the claims. Furthermore, nothing disclosed herein is intended to be made public, whether expressly stated in the claims or not. Elements of the claims shall not be construed as Means Plus Function unless expressly stated using the phrase “means.”

[0175] The specific order or hierarchical structure of blocks in the disclosed process is understood to be an example of a descriptive approach. It is understood that, based on design preferences, the specific order or hierarchical structure of blocks in the process can be rearranged within the scope of the foregoing description. The attached method claims present various block components in an exemplary order and are not limited to the specific order or hierarchical structure presented.

[0176] The foregoing description of the disclosed embodiments is provided to enable those skilled in the art to create or use the disclosed subject matter. Various modifications to such embodiments are readily apparent to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit or scope of the foregoing description. Accordingly, the foregoing description is not limited to the embodiments disclosed herein and should be interpreted in the broadest sense to be consistent with the principles and new features disclosed herein.

[0177] The various embodiments shown and described are provided solely as examples to illustrate the various features of the claims. However, the features shown and described with respect to a particular embodiment are not necessarily limited to that embodiment and may be used or combined with other embodiments shown and described. Furthermore, the claims are not intended to be limited by any one embodiment.

[0178] The above-mentioned description of the method and process flowchart are provided for illustrative purposes only and do not require or imply that the blocks of the various embodiments should be performed in the order presented. As those skilled in the art will understand, the order of the blocks of the above-mentioned embodiments may be any order. Words such as “hereafter,” “then,” and “next” are not intended to restrict the order of the blocks, and these words are used simply to guide the reader through the description of the method. Also, references to claim components mentioned in the singular using, for example, “a,” “an,” or “the” should not be construed as limiting the element to the singular.

[0179] The various exemplary logic blocks, modules, circuits, and algorithmic blocks described in connection with the embodiments disclosed herein can be implemented as electronic hardware, computer software, or a combination of both. To illustrate this interoperability between hardware and software, various exemplary components, blocks, modules, circuits, and blocks are generally described according to their function. Whether these functions are implemented in hardware or software depends on the specific application and the design constraints imposed on the overall system. A person skilled in the art may implement the functions described for each specific application in various ways, but such implementation decisions should not be construed as departing from the scope of this disclosure.

[0180] The hardware used to implement the various exemplary logic, logic blocks, modules, and circuits described in relation to the embodiments disclosed herein can be implemented or run by general-purpose processors, DSPs, ASICs, FPGAs or other programmable logic devices, individual gate or transistor logic, individual hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but instead, a processor may be a conventional processor, controller, microcontroller, or state machine. A processor can be implemented in a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors coupled with a DSP core, or other similar configurations. Alternatively, some blocks or methods may be implemented by circuits adapted to a given function.

[0181] In some exemplary embodiments, the functions described can be implemented in hardware, software, firmware, or any combination thereof. When implemented in software, the functions can be stored as one or more instructions or codes in a non-temporary computer-readable storage medium or a non-temporary processor-readable storage medium. Blocks of methods or algorithms disclosed herein can be implemented in processor-executable software modules that can reside in a non-temporary computer-readable or processor-readable storage medium. A non-temporary computer-readable or processor-readable storage medium can be any storage medium accessible by a computer or processor. For example, such a non-temporary computer-readable or processor-readable storage medium includes, but is not limited to, RAM, ROM, EEPROM, flash memory, CD-ROM or other optical disk storage devices, magnetic disk storage devices or other magnetic storage devices, or any other medium accessible by a computer that can be used to store desired program code in the form of instructions or data structures. The terms "Disk" and "Disc" used herein include compact discs (CDs), laserdiscs, optical discs, digital-purpose discs (DVDs), floppy disks, and Blu-ray discs, where a "Disk" typically reproduces data magnetically, and a "Disc" reproduces data optically using a laser. The aforementioned combinations also fall within the range of non-temporary computer-readable and processor-readable media. Furthermore, the operation of a method or algorithm may exist as one or any combination or set of code and / or instructions on non-temporary processor-readable and / or computer-readable storage media that can be incorporated into a computer program product.

[0182] The foregoing description of the disclosed embodiments is provided to enable those skilled in the art to manufacture or use the disclosure. Various modifications to these embodiments are readily apparent to those skilled in the art, and the general principles defined herein can be applied to some embodiments without departing from the spirit or scope of the disclosure. Accordingly, the disclosure is not limited to the embodiments disclosed herein, and the following claims and the broadest extent to which they coincide with the principles and novel features disclosed herein should be interpreted.

Claims

1. A vehicle-mounted LiDAR (Light Detection and Ranging) system, An input optical path configured to receive a beam from a laser source, A first optical path and a plurality of second optical paths branch off from the aforementioned input optical path, A first optical amplifier coupled to the first optical path and configured to output a local oscillator (LO) signal, A plurality of second optical amplifiers coupled to each of the plurality of second optical paths—each of which is selectively turned on to temporally multiplex and modulate the beam received through the plurality of second optical paths and to output the modulated optical signal of the beam— One or more optical components configured to transmit the modulated optical signal to the environment, receive a return optical signal reflected from one or more objects in the environment, and pair the return optical signal with the LO signal, A LIDAR system including [this].

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 turned on or off to perform signal modulation of the beam.

4. The LiDAR system according to claim 2, wherein one of the one or more SOAs is configured to change the drive current of one of the one or more SOAs in order to perform signal modulation of the beam.

5. The LIDAR system according to claim 1, wherein the LIDAR system comprises at least one of a silicon photonics circuit, a PLC (Photon Lightwave Circuit), or a III-V semiconductor circuit.

6. The aforementioned LIDAR system is a III-V semiconductor circuit, The LIDAR system according to claim 1, wherein the III-V semiconductor circuit comprises at least one of indium phosphide (InP), indium monoarsenide (InAs), or gallium and arsenide (GaAs).

7. The first optical amplifier includes a plurality of third optical amplifiers, The LIDAR system according to claim 1, wherein one of the plurality of third optical amplifiers is selectively turned on to output the LO 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 beam.

10. The LiDAR system according to claim 8, wherein the first SOA is configured to change the drive current of the first SOA in order to perform signal modulation of the beam.

11. The system further includes one or more phase modulators coupled to the first optical path or the second optical path, The LIDAR system according to claim 1, wherein the one or more phase modulators are configured to perform phase modulation of the beam.

12. The control circuit further includes a control circuit configured to generate one or more control signals for turning the first optical amplifier and the plurality of second optical amplifiers on or off, The LIDAR system according to claim 11, wherein the one or more control signals indicate a time sequence for turning on or off the plurality of second optical amplifiers.

13. The LIDAR system according to claim 12, wherein the control circuit is configured to turn on or off the output signal of the first optical amplifier in synchronization with a time sequence for turning on or off the plurality of second optical amplifiers.

14. The LIDAR system according to claim 12, wherein the control circuit is configured to multiplex the output signals of the plurality of second optical amplifiers according to the time sequence.

15. The LIDAR system according to claim 12, wherein the control circuit is configured to multiplex the plurality of second optical paths according to the time sequence.

16. A vehicle-mounted LiDAR (Light Detection and Ranging) system, An input optical path configured to receive a beam from a laser source, A first optical path and a plurality of second optical paths branch off from the aforementioned input optical path, A first optical amplifier coupled to the first optical path and configured to output a first local oscillator (LO) signal and a second LO signal, A plurality of second optical amplifiers coupled to each of the plurality of second optical paths—two of the plurality of second optical amplifiers being selectively turned on to modulate the beam received through the second optical path and to output a first modulated optical signal associated with the first LO signal and a second modulated optical signal associated with the second LO signal, Including one or more optical components, The one or more optical components are The first and second modulated optical signals are transmitted to the environment via the first and second transmit (TX) channels, The system receives first and second return light signals reflected from one or more objects in the environment. A LiDAR system that pairs the first and second return optical signals with the first and second LO signals, respectively.

17. Includes one or more processors, The one or more processors described above are: The input optical path is configured to receive the beam from the laser source. A first optical amplifier coupled to the first optical path outputs a local oscillator (LO) signal—the first optical path and the plurality of second optical paths each branch off from the input optical path, and the plurality of second optical amplifiers each are coupled to the plurality of second optical paths— The beams received through the plurality of second optical paths are temporally multiplexed and modulated, and the plurality of second optical amplifiers are selectively turned on to output the modulated optical signal of the beams. The modulated optical signal is transmitted to the environment. The return light signal reflected from one or more objects in the environment is received. An autonomous vehicle control system configured to pair the return optical signal with the LO signal.

18. The autonomous vehicle control system according to claim 17, wherein the plurality of second optical amplifiers include one or more semiconductor optical amplifiers (SOAs).

19. A LIDAR (Light Detection And Ranging) system and one or more processors are included. The aforementioned LIDAR system is An input optical path configured to receive a beam from a laser source, A first optical path and a plurality of second optical paths branch off from the aforementioned input optical path, A first optical amplifier coupled to the first optical path and configured to output a first local oscillator (LO) signal and a second LO signal, The system includes a plurality of second optical amplifiers coupled to each of the plurality of second optical paths, two of which are selectively turned on to modulate the beam received through the second optical path and to output a first modulated optical signal associated with the first LO signal and a second modulated optical signal associated with the second LO signal, respectively. The one or more processors described above are: The first and second modulated optical signals are transmitted to the environment via the first and second transmit (TX) channels, The system receives first and second return light signals reflected from one or more objects in the environment. An autonomous vehicle configured to pair the first and second return optical signals with the first and second LO signals, respectively.

20. The autonomous vehicle according to claim 19, wherein the plurality of second optical amplifiers include one or more semiconductor optical amplifiers (SOAs).

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