Optical detection and distance measurement system including modular assembly

Abstract

The modular LIDAR sensor system includes a seed laser configured to output a beam; a modular modulator coupled to receive the beam output from the seed laser and modulate the beam to produce a modulated beam; a modular amplifier configured to receive the modulated beam from the modular modulator and produce an amplified beam; and a modular transceiver chip coupled to the modular modulator and the modular amplifier, the modular transceiver chip configured to emit the beam normal to a first surface of the modular transceiver chip through an optical window and receive the beam reflected from a target through the optical window.

Description

Technical Field

[0001] The present disclosure generally relates to a modular assembly of components for a light detection and ranging (LIDAR) system, and more specifically to a LIDAR system including a modular modulator, a modular amplifier, and a modular transceiver chip.

Background Art

[0002] LIDAR sensor systems are used in a variety of applications ranging from altitude measurements to imaging and collision avoidance. For the design and implementation of LIDAR sensor systems, a photonic integrated circuit (PIC) or an integrated optical circuit, which is a chip including photonic components, can be used. In the past, attempts have been made to incorporate more photonic components of LIDAR systems into a single PIC. However, the problem with these attempts is that they are complex and the yield is significantly reduced during the manufacture of these complex chips. In other prior art approaches, optical fiber connectors have been used to couple various components of LIDAR systems. The problem with the use of optical fiber cable connectors is that in addition to the additional space required, there are configuration complexity and alignment problems that occur when using optical fibers and connectors. Therefore, there is a need for a method of constructing a LIDAR system with high yield and reduced complexity.

Summary of the Invention

[0003] Embodiments of the present disclosure relate to a modular architecture for a vehicle light detection and distance measurement (LIDAR) sensor system, more specifically, a LIDAR sensor system composed of modular components and a method for configuring the components for cooperation and communication. According to one aspect of the subject matter described herein, the LIDAR sensor system includes a seed laser configured to output a beam, a modular modulator configured to receive the beam output from the seed laser and modulate the beam to produce a modulated beam, a modular amplifier configured to receive the modulated beam from the modular modulator and produce an amplified beam—the modular amplifier includes a particular semiconductor optical amplifier having a plurality of apertures—and a modular transceiver chip coupled to the modular modulator and the modular amplifier—the transceiver chip is configured to emit the beam perpendicularly from a first surface of the transceiver chip through an optical window and to receive the beam reflected from an object through the optical window.

[0004] These embodiments and other embodiments may each optionally include one or more of the following features. For example, the features may include a seed laser that includes a laser having a grating structure that provides optical feedback to output a beam, or a lens that couples the beam to a modular modulator—the lens having a pitch in the range of 450 to 550 micrometers. For example, the features may also include the modular modulator performing in-phase and quadrature modulation or frequency modulation to produce a modulated beam. In other examples, the features may include the modular modulator and seed laser being integrated on a single chip to form a seed laser assembly. In other features, the seed laser assembly is mounted on a first submount, and a modular transceiver chip coupled to the modular modulator is mounted on a second submount for aligning the height of the seed laser assembly with the height of the modular transceiver chip for optical coupling. In some features, the modular amplifier includes a semiconductor optical amplifier or a tapered semiconductor optical amplifier configured to receive a modulated beam from the modular modulator and produce a beam amplified by stimulated emission. For example, in one embodiment, the modular amplifier comprises one of indium phosphide (InP), gallium arsenide (GaAs), silicon nitride (SiN), indium arsenide (InAs), gallium nitride (GaN), or indium antimonide (InSb). The feature may also include that a particular semiconductor optical amplifier has additional material on its sides for bow management. Furthermore, the feature may include that the modular amplifier comprises a first bar attached to a first part of the modular amplifier and a second bar attached to a second part of the modular amplifier, wherein the second bar has a coefficient of thermal expansion matching that of the first bar, and the first and second bars are configured to lower the junction temperature of the modular amplifier, or the first and second bars are 16 aperture bars, and the modular amplifier may further include a feature comprising 16 tapered semiconductor optical amplifiers.For example, a feature may include a modular modulator optically coupled to a modular amplifier by a lens array, or a feature in which the lens array compensates for a height difference between a first height of the modular modulator submount and a second height of the modular amplifier submount. A feature may also include a feature in which the modular modulator, modular amplifier, and modular transceiver chips are fully tested before integration to enable high yield. Other features may include a splitter that couples the modular modulator to a modular amplifier, and the splitter may include a 1-to-16 splitter with a pitch in the range of 450 to 550 micrometers. For example, a feature may include a lens array that couples the modular modulator to a modular amplifier, and a splitter that includes a plurality of 1-to-4 splitter chips with a pitch in the range of 450 to 550 micrometers, where the lens array includes four lenses with a pitch in the range of 450 to 550 micrometers. Furthermore, the features may include the integration of modular modulators, modular amplifiers, and modular transceiver chips horizontally or vertically. Additionally, the features may include the integration of modular modulators, modular amplifiers, and modular transceiver chips as part of an autonomous vehicle or an autonomous vehicle control system.

[0005] According to another aspect of the subject matter described herein, a vehicle LiDAR sensor system includes: a seed laser configured to output a beam; a modulator coupled to the seed laser to receive a beam from the seed laser and modulate the beam to produce a modulated beam; an amplifier coupled to the modulator to receive the modulated beam from the modulator and produce an amplified beam; and a transceiver coupled to the modulator and amplifier—the transceiver is configured to process and emit a beam amplified to the transceiver in a predetermined direction by surface radiation and to receive and process a beam reflected from an object in the environment in which the vehicle is located. In some embodiments of this disclosure, an autonomous vehicle control system may include one or more processors configured to determine at least one of the distance to an object or the velocity of an object using the LiDAR sensor system described herein and the reflected beam, and to control the operation of the autonomous vehicle in response to at least one of the distance or velocity. In some embodiments of this disclosure, the autonomous vehicle may include the LiDAR sensor system described herein, a steering system, a braking system, and a vehicle controller. The vehicle controller may include one or more processors configured to use a reflected beam to determine at least one of the distance to an object or the velocity of the object, and to control the operation of at least one of the steering system and the braking system in response to at least one of the distance or velocity.

[0006] These embodiments and other embodiments may each optionally include one or more of the following features. For example, a feature may include a transceiver that includes an optical window, which is a passage through which an amplified beam is emitted and a reflected beam is received. A feature may also include surface emission, which includes emitting an amplified beam perpendicularly from the surface of the transceiver. For example, a feature may also include a feature in which the transceiver processes a beam reflected from an object to detect a photocurrent and couples the detected photocurrent to a transimpedance amplifier. In other examples, a feature may include a feature in which a modulator and a seed laser are integrated into a seed laser assembly, the seed laser assembly is mounted on a first submount, and the transceiver is mounted on a second submount for aligning the height of the seed laser and the height of the transceiver for optical coupling. In other examples, a feature may include a feature in which the amplifier includes a semiconductor optical amplifier, the semiconductor optical amplifier is integrated with a U-shaped passive component for optical amplification. In other examples, a feature may include a feature in which the amplifier includes a tapered semiconductor optical amplifier configured to receive a modulated beam from a modulator and produce an amplified beam by stimulated emission. In one example, the amplifier may include at least one of indium phosphide (InP), gallium arsenide (GaAs), indium arsenide (InAs), gallium nitride (GaN), indium antimonide (InSb), or rare earth doped materials. For example, a feature may include a modulator optically coupled to the amplifier via a first lens array, the first lens array compensating for the height difference between a first height of the modulator submount and a second height of the amplifier submount, and the amplifier optically coupled to a transceiver via a second lens array. In one example, the first lens array, the amplifier, and the second lens array are integrated on a single chip. In another example, another feature may include a splitter that couples the output of the modulator to the input of the amplifier, the splitter may include a 1-to-16 splitter having a pitch in the range of 450 to 550 micrometers.In other examples, the feature may also include a first lens array that couples the output of a splitter to the input of an amplifier, the splitter comprising a plurality of 1-to-4 splitter chips having a pitch in the range of 450-550 micrometers, and the first lens array comprising four lenses having a pitch in the range of 450-550 micrometers. Furthermore, the feature may include a feature in which the modulator, amplifier, and transceiver are each modular in structure and aligned horizontally for optical coupling, and the optical ports of the horizontally aligned modulator, amplifier, and transceiver have matching pitch, matching optical mode size, and matching facet angle. In other examples, the feature may include a feature in which the modulator, amplifier, and transceiver are each modular in structure and aligned vertically for optical coupling.

[0007] Those skilled in the art will understand that this abstract is illustrative and not intended to limit in any way. Any of the features described herein can be used in conjunction with other features, and any subset of such features can be used in combination by various embodiments. Other aspects of the apparatus and / or process described herein, as defined solely by the claims, features and merits of the invention will become apparent from the detailed description disclosed herein together with the accompanying drawings. Furthermore, the language used in this disclosure has been selected primarily for readability and explanatory purposes and is not intended to limit the scope of the subject matter disclosed herein. [Brief explanation of the drawing]

[0008] Some embodiments shown in the attached drawings are provided as examples only and are not limiting; similar reference numerals refer to similar elements.

[0009] [Figure 1a] A block diagram showing an example of a system environment for an autonomous vehicle according to some embodiments.

[0010] [Figure 1b]A blockchain showing an example of a system environment for an autonomous commercial truck vehicle in some embodiments.

[0011] [Figure 1c] A blockchain showing an example of a system environment for an autonomous commercial truck vehicle in some embodiments.

[0012] [Figure 1d] A blockchain showing an example of a system environment for an autonomous commercial truck vehicle in some embodiments.

[0013] [Figure 2] A block diagram showing an example of a LiDAR sensor system for autonomous vehicles according to some embodiments.

[0014] [Figure 3] This is a high-level block diagram showing exemplary components of a LiDAR sensor system for autonomous vehicles according to some embodiments.

[0015] [Figure 4] This is a high-level block diagram showing exemplary modular components of a horizontally integrated LiDAR sensor system for an autonomous vehicle according to some embodiments.

[0016] [Figure 5] This is a high-level block diagram showing exemplary modular components of a horizontally or vertically integrated LiDAR sensor system for an autonomous vehicle according to some embodiments.

[0017] [Figure 6] This is a high-level block diagram showing an exemplary plan view of modular components of a LiDAR sensor system for an autonomous vehicle according to one embodiment.

[0018] [Figure 7]A cross-sectional view showing an exemplary integrated chip packaging of a modular LIDAR sensor system for an autonomous vehicle according to some embodiments.

[0019] It should be understood that alternative embodiments of the structures and methods illustrated herein can be used without departing from the principles described herein.

Mode for Carrying Out the Invention

[0020] In a particular embodiment, the modular LIDAR sensor system 300 includes a seed laser 308, a modular modulator 306, a modular amplifier 304, and a modular transceiver chip 302. The LIDAR sensor system 300 is advantageous in that each of these components 302, 304, 306, and 308 has a modular design. Such a modular design is particularly advantageous in that each component is an individual integrated circuit, and these individual integrated circuits are optically coupled by microlenses. This modularity allows the modular LIDAR sensor system 300 to overcome the shortcomings of the aforementioned prior art, as each individual integrated circuit has a much higher yield than each of the modular components. This modular design allows the effectiveness of each component to be tested individually in various aspects. Furthermore, this modular design also provides greater configuration flexibility, as different versions of the configuration of any of the modular modulator 306, modular amplifier 304, or modular transceiver chip 302 can be used with other modular components. In some embodiments, the LIDAR sensor system 300 may also include an integrated chip package for the LIDAR sensor that provides a path for optical signals transmitted in and out of the LIDAR sensor and defines the configuration of the optical components for dissipating heat generated by the optical components for improved performance. The modular transceiver chip 302 may be configured to emit a beam perpendicularly from a first surface of the modular transceiver chip 302 through an optical window and to receive the beam reflected from a target through the optical window.

[0021] In the following description, for the purpose of providing a complete understanding of various aspects of the various exemplary embodiments, numerous specific details are presented for illustrative purposes. It should be noted that the specific exemplary embodiments can be implemented in various cases without all specific details and / or by variations, substitutions, and combinations of the various features and elements described herein. Detailed references are made to the embodiments of the present disclosure, and examples thereof are shown in the accompanying drawings. As far as possible, the same reference numbers are used in the drawings and the description to refer to the same or similar parts.

[0022] Also, relative terms such as "lower" or "bottom side" or "back" or "down" and "upper" or "top side" or "front" or "up" can be used herein to describe the relationship of one element to another as shown in the drawings. The relative terms are intended to be understood to include other directions of the device in addition to the directions shown in the drawings. For example, if one of the devices in the drawings is turned over, an element described as being "below" another element will be "above" the other element. Thus, the exemplary term "bottom side" can include both the "bottom side" and the "top side" directions depending on the specific direction of the drawing. Similarly, if one of the devices in the drawings is turned over, an element described as the "bottom" or "base" of another element will be in the "up" direction of the other element. Thus, the exemplary terms "down" or "downward" can include both the up and down directions.

[0023] In some figures, similar numbers refer to drawings indicating similar parts. Figure 1a shows one embodiment of a system environment 100A for an autonomous vehicle 111A in which various technologies disclosed herein can be implemented. For example, the vehicle 111A may include a powertrain 102, which includes a prime mover 104 driven by an energy source 106 and capable of supplying power to a drivetrain 108, and a control system 110, which includes directional control 112, powertrain control 114, and brake control 116. The vehicle 111A can be implemented as any number of different types of vehicles, including vehicles that can transport people and / or cargo and can travel on land, and it should be recognized that the aforementioned components 102-116 may vary considerably depending on the type of vehicle in which these components are used.

[0024] For simplicity, the embodiments discussed below focus on wheeled land vehicles such as automobiles, vans, trucks, and buses. In such embodiments, the prime mover 104 may include one or more electric motors and / or internal combustion engines (among others). The energy source 106 may include, for example, a fuel system (e.g., providing gasoline, diesel, hydrogen, etc.), a battery system, solar panels or other renewable energy sources and / or a fuel cell system. The drivetrain 108 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 104 into vehicle motion, and include one or more brakes configured to controllably stop or decelerate the vehicle 111A and a directional or steering component suitable for controlling the trajectory of the vehicle 111A (e.g., a rack and pinion steering linkage that causes the wheels to pivot about a generally perpendicular axis in order to change the angle of the rotation plane of the wheels with respect to the longitudinal axis of the vehicle). In some embodiments, a combination of powertrain and energy source can be used (e.g., in the case of an electric / gas hybrid vehicle), and in other embodiments, multiple electric motors (e.g., dedicated to individual wheels or axles) can be used as prime movers 104. In the case of a hydrogen fuel cell implementation, prime mover 104 may include one or more electric motors, and energy source 106 may include a fuel cell system driven by hydrogen fuel.

[0025] Direction control 112 may include one or more actuators and / or sensors for controlling and receiving feedback from direction or steering components to enable the vehicle 111A to follow a desired trajectory. Powertrain control 114 may be configured to control the speed and / or direction of the vehicle 111A by controlling the output of the powertrain 102, such as controlling the output power of the prime mover 104 and controlling the gears of the transmission in the drivetrain 108. 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 slow down or stop the vehicle 111A.

[0026] Other vehicle types, including but not limited to all-terrain vehicles or tracked vehicles, and construction equipment, can utilize different powertrains, drivetrains, energy sources, directional control, powertrain control, and brake control. Furthermore, in some embodiments, some components may be combined, although, 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.

[0027] In the shown embodiment, various levels of autonomous control, including fully or semi-autonomously, of the vehicle 111A can be implemented in the vehicle control system 120, which includes 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)).

[0028] Sensor 130 may include a variety of sensors suitable for collecting information from the environment surrounding the vehicle for use in controlling the operation of the vehicle 111A. For example, sensor 130 may include one or more detection and distance measuring sensors (e.g., at least one of a RADAR sensor 134 and a LIDAR sensor 136), a 3D positioning sensor 138, and satellite navigation systems such as GPS (Global Positioning System), GLONASS (Globalnaya Navigazionnaya Sputnikovaya Sistema, or Global Navigation Satellite System), BeiDou Navigation Satellite System (BDS), Galileo, Compass, etc. The 3D positioning sensor 138 can be used to determine the vehicle's position on Earth using satellite signals. Sensor 130 may selectively include a camera 140 and / or an IMU (Inertial Measurement Unit) 142. The 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 111A in three directions. One or more encoders 144, such as wheel encoders, can be used to monitor the rotation of one or more wheels of the vehicle 111A. In some embodiments, the LIDAR sensor 136 may include a silicon photonic device structure for a coherent LIDAR system, as described in detail below.

[0029] The output of sensor 130 can be provided to a set of control subsystems 150, including a position estimation subsystem 152, a recognition subsystem 154, a planning subsystem 156, 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" or "attitude estimation") of vehicle 111A, primarily within the surrounding environment and generally within a reference frame. The recognition subsystem 154 may perform functions such as detecting, tracking, and / or identifying objects in the surrounding environment of vehicle 111A. Machine learning models in some embodiments can be used to track objects. The planning subsystem 156 may perform functions such as planning the movement trajectory or route of vehicle 111A over a period of time frame, given a desired destination as well as primarily static and moving objects in the environment. Machine learning models in some embodiments 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 vehicle 111A. Similarly, machine learning models can be used to generate one or more signals to control the autonomous vehicle 111A in order to realize a planned trajectory.

[0030] It will be understood that the set of components for the vehicle control system 120 shown in Figure 1a is merely an example. In some embodiments, individual sensors may be omitted. Additionally or alternatively, in some embodiments, multiple sensors of the same type shown in Figure 1a may be used redundantly and / or to cover different areas around the vehicle. Also, other types of sensors beyond those described above may be added to provide actual sensor data related to the operation and environment of the wheeled land vehicle. Similarly, different types and / or combinations of control subsystems may be used in other implementations. Also, although subsystems 152-158 are shown as separate from the processor 122 and memory 124, it should be understood that in some embodiments, some or all of the functions of subsystems 152-158 may be implemented as program code instructions 126 residing in one or more memories 124 and 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 logics, various processors, various field-programmable gate arrays ("FPGAs"), various application-specific integrated circuits ("ASICs"), various real-time controllers, and, as mentioned above, multiple subsystems can utilize circuits, processors, sensors, and / or other components. Furthermore, the various components of the vehicle control system 120 can be networked in various ways.

[0031] In some embodiments, the vehicle 111A may further include a secondary vehicle control system (not shown) that can be used as a redundant or backup control system for the vehicle 111A. In some embodiments, the secondary vehicle control system may be able to fully operate the autonomous vehicle 111A in the event of an adverse event occurring in the vehicle control system 120, while in other embodiments, the secondary vehicle control system may only have limited functions, such as performing a controlled stop of the vehicle 111A in response to an adverse event detected by the primary vehicle control system 120. In other embodiments, the secondary vehicle control system may also be omitted.

[0032] 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. Each memory can also be considered to include memory storage devices physically located elsewhere in the vehicle 111A, 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 122 shown in Figure 1a, or entirely separate processors, can be used to implement additional functions within the vehicle 111A other than for the purpose of autonomous control, such as controlling the entertainment system and implementing the operation of doors, lighting, convenience functions, etc.

[0033] Furthermore, for additional storage devices, vehicle 111A 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.

[0034] Furthermore, the vehicle 100 may include a user interface 118, such as one or more displays, touchscreens, voice and / or gesture interfaces, buttons and other haptic controls, which enables the vehicle 111A to receive a number of inputs from a user or operator and generate outputs for 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.

[0035] The vehicle 111A may also include one or more network interfaces, such as a network interface 162 suitable for communication with one or more networks 176 to enable communication with other computers and electronic devices, including a central service such as a cloud service that serves as a medium for receiving information including machine learning models and other data learned for use in the vehicle 111A's autonomous control. The one or more networks 176 may be, for example, communication networks and may include one or more local area networks ("LANs") such as a wide area network ("WAN") such as the Internet, a Wi-Fi LAN, a mesh network, and one or more bus subsystems. The one or more networks 176 may selectively utilize one or more standard communication technologies, protocols, and / or inter-process communication technologies. In some embodiments, data collected by one or more sensors 130 can be uploaded to a computing system 172 via the network 176 for further processing. In the illustrated embodiment, the vehicle 111A can communicate with the computing system 172 via the network 176 and signal lines 178. In some embodiments, the computing system 172 is a cloud-based computing device. The additional processing of autonomous vehicle data by the computing system 172 in many embodiments will be explained with reference to Figure 2.

[0036] 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 upon, various computer software applications, components, programs, objects, modules, data structures, etc., as described in detail below. Furthermore, various applications, components, programs, objects, modules, etc., may also be performed on one or more processors of other computers (e.g., computing system 172) connected to vehicle 100 via network 176 in a distributed, cloud-based, or client-server computing environment where processing necessary to embody the functionality of a computer program can be allocated to numerous computers and / or services via the network.

[0037] Generally, routines performed to implement the various embodiments described herein are referred to herein as “program code,” whether they are implemented as part of an operating system or as a specific application, component, program, object, module, or sequence of instructions, or as a subset thereof. Program code generally resides in various memory and storage devices for various periods of time and, when read and executed by one or more processors, includes one or more instructions that 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 should be understood that the various embodiments described herein can be distributed as various forms of program products, and that embodiments can be implemented independently of the specific type of computer-readable medium used to actually carry out such distribution.

[0038] 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.).

[0039] 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 merely 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. Also, considering the generally infinite number of ways in which a computer program can be composed of routines, procedures, methods, modules, objects, etc., and the various ways in which program functions can be 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.

[0040] The exemplary 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.

[0041] The truck may include a LiDAR system (e.g., vehicle control system 120 in Figure 1a, LiDAR sensor system 201 in Figure 2). 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.

[0042] FM or phase-modulated (PM) LiDAR systems can offer significant advantages over conventional LiDAR systems for automotive and / or commercial truck applications. Firstly, in some cases, objects (e.g., pedestrians wearing dark clothing) may have low reflectivity, in that only a small amount (e.g., less than 10%) of the incident light entering 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%), in that a large amount of the incident light entering the object is reflected back to the sensor of the FM LiDAR system.

[0043] 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.

[0044] To achieve such improved detection capabilities, 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 detection capability) for eye safety.

[0045] Therefore, by detecting objects at greater distances, FM LiDAR systems can gain more time to react to unexpected obstacles. In fact, even an additional few milliseconds can improve stability and convenience, especially for large vehicles traveling at high speeds on highways (e.g., commercial trucks).

[0046] Another advantage of FM LIDAR systems is their ability to instantly provide accurate velocity for each data point. In some embodiments, velocity measurement is performed using the Doppler effect, which shifts the frequency of light received from an object based on at least one of the following: radiative 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.

[0047] Furthermore, instantaneous velocity calculation makes 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 return signals (e.g., optical reception signals (Hits)) from an object 300m away, but if these return signals provide a velocity value of interest (e.g., a vehicle approach speed of 70mph or more), the FM LIDAR system and / or the autonomous vehicle control system can determine individual weights for the probability associated with the object.

[0048] Rapid identification and / or tracking by FM LiDAR systems provides autonomous vehicle control systems with more time to activate the vehicle. Furthermore, a better understanding of how fast objects are moving allows autonomous vehicle control systems to plan better responses.

[0049] Another advantage of FM LIDAR systems is that they have less static noise compared to conventional LIDAR systems. Conventional LIDAR systems are designed to be highly sensitive to light, and their performance typically degrades in bright sunlight. These systems tend to suffer from crosstalk (e.g., when sensors are confused by each other's light pulses or beams) and self-interference (e.g., when 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."

[0050] On the other hand, FM LiDAR systems do not experience these kinds of problems 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 return 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 safer and smoother operation.

[0051] 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.

[0052] Figure 1b is a block diagram showing an example of a system environment for an autonomous commercial truck vehicle according to some embodiments. Environment 100B includes a commercial truck 180B for carrying cargo 182B. In some embodiments, the commercial truck 180B may include a vehicle configured for long-distance freight transport, regional freight transport, intermodal freight transport (i.e., transport in which a road-based vehicle is used as one of several modes of transport for transporting goods) and / or any other road-based freight transport applications. The commercial truck 180B 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 182B may be commodities and / or agricultural products. The commercial truck 180B may include trailers for carrying cargo 182B, such as a flatbed trailer, a lowboy trailer, a step deck trailer, an expandable flatbed trailer, a side kit trailer, etc.

[0053] Environment 100B includes object 111B (shown as another vehicle in Figure 1b) located within a distance of 30 meters or less from the truck.

[0054] The commercial truck 180B may include a LiDAR system 184B (e.g., an FM LiDAR system, the vehicle control system 120 in Figure 1a, the LiDAR system 201 in Figure 2) for determining the distance to an object 111B and / or measuring the speed of the object 111B. Figure 1b shows one LiDAR system 184B mounted on the front of the commercial truck 180B, but the number of LiDAR systems and the mounting area of ​​the LiDAR systems in the commercial truck are not limited to a specific number and specific area. The commercial truck 180B may include any number of LiDAR systems 184B (or components such as sensors, modulators, coherent signal generators) mounted on any area of ​​the commercial truck 180B (e.g., front, rear, sides, top, bottom, underside, and / or bottom), which can facilitate object detection in any free space compared to the commercial truck 180B.

[0055] As shown in the diagram, the LIDAR system 184B in environment 100B may be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) at a short distance (e.g., 30 meters or less) from the commercial truck 180B.

[0056] Figure 1c is a block diagram showing an example of a system environment for an autonomous commercial truck vehicle according to some embodiments. Environment 100C includes the same components as those included in Environment 100B (e.g., commercial truck 180B, cargo 182B, LIDAR system 184B, etc.).

[0057] Environment 100C includes objects 111C (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 180B. As shown in the illustration, the LIDAR system 184B 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 180B.

[0058] Figure 1d is a block diagram showing an example of a system environment for an autonomous commercial truck vehicle according to some embodiments. Environment 100D includes the same components as those included in Environment 100B (e.g., commercial truck 180B, cargo 182B, LIDAR system 184B, etc.).

[0059] Environment 100D includes objects 111D (shown as other vehicles in Figure 1d) that are within a distance of 150 meters or more from the commercial truck 180B. As shown in the illustration, the LIDAR system 184B 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 180B.

[0060] In commercial truck applications, the increased weight required of the vehicle and the correspondingly longer stopping distances necessitate the effective detection of objects at all distances. FM LiDAR systems (e.g., FMCW and / or FMQW systems) or PM LiDAR systems are well-suited to commercial truck applications due to the aforementioned advantages. Therefore, commercial trucks equipped with these systems can improve the safety of not only the commercial 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 driving applications where a driver is on board the commercial truck and some functions of the commercial truck operate autonomously using the FM or PM LiDAR system, or in fully autonomous driving applications where the commercial truck operates fully autonomously using the FM or LiDAR system alone or in combination with other vehicle systems.

[0061] 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.

[0062] For frequency-modulated continuous-wave (FMCW) LiDAR for vehicle applications, FMCW measurement and signal processing methodologies are used, but it may be advantageous to operate the LiDAR system using quasi-CW modulation, as the optical signal is not always in an on state (e.g., activation, power supply, transmission, etc.). In some embodiments, quasi-CW modulation may have a duty cycle of 1% 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) will improve, and / or the signal processing requirements for consistently integrating all the energy over a longer period of time will be reduced.

[0063] Figure 2 is a block diagram illustrating an exemplary environment for a LiDAR sensor system for an autonomous vehicle according to one embodiment. Environment 200 includes a LiDAR sensor system 201, which includes 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).

[0064] 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 circuits, programmable logic controllers (PLCs), or III-V semiconductor circuits.

[0065] In some embodiments, the first semiconductor substrate and / or the first semiconductor package may include a TX path, and the second semiconductor substrate and / or the second semiconductor package may include an RX path. In some arrangements, the RX input / output ports and / or the TX input / output ports may occur (or be formed / arranged / located / placed) along one or more edges of one or more semiconductor substrates and / or semiconductor packages.

[0066] Environment 200 includes one or more transmitters 216 and one or more receivers 222.

[0067] 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.

[0068] Environment 200 includes a vehicle control system (e.g., vehicle control system 120 in Figure 1a) 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.

[0069] The TX path may include a laser source 202, modulators 204A and 204B, an amplifier 206, and one or more transmitters 216. The RX path may include one or more receivers 222, a mixer 208, a detector 212, a transimpedance amplifier (TIA) 214, and one or more analog-to-digital converters (ADCs). 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 in order to support the operation of the vehicle.

[0070] 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 1400 nanometers and 1440 nanometers.

[0071] The laser source 202 may be configured to provide an optical signal to the modulator 204A, which is configured to generate a modulated optical signal by modulating the phase and / or frequency of the optical signal using continuous wave (CW) modulation or quasi-CW modulation based on a first radio frequency (RF) signal (indicated as "RF1" in Figure 2). The modulator 204A may be configured to transmit the modulated optical signal to the amplifier 206. The amplifier 206 may be configured to amplify the modulated optical signal to generate an amplified optical signal to the optical system 210 via one or more transmitters 216. One or more transmitters 216 may include one or more optical waveguides or antennas.

[0072] The optical system 210 may be 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 on the RX path via one or more receivers 222. One or more receivers 222 may include one or more optical waveguides or antennas. In some configurations, the transmitter 216 and receivers 222 may constitute one or more transceivers (not shown in Figure 2). In some configurations, one or more transceivers may include monostatic or bistatic transceivers.

[0073] The laser source 202 may be configured to provide an LO signal to modulator 204B, which is configured to generate a modulated LO signal by modulating 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), and to transmit the modulated LO signal to mixer 208 in the RX path.

[0074] Mixer 208 may be configured to mix (e.g., combine, multiply, etc.) the modulated LO signal with the return signal to produce a down-converted signal, and to transmit the down-converted signal to detector 212. In some configurations, mixer 208 may be configured to transmit the modulated LO signal to detector 212.

[0075] The detector 212 may be configured to generate an electrical signal based on the downconverted 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 downconverted signal and the modulated signal.

[0076] The TIA214 may be configured to amplify electrical signals and transmit the amplified electrical signals to the vehicle control system 120 via one or more ADC220s.

[0077] In some embodiments, TIA214 is 5 picowatts per square root Hertz (i.e., 5 × 10⁻¹⁶ 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 kilohms and 25 kilohms.

[0078] In some embodiments, the detector 212 and / or TIA 214 may have a bandwidth of 3 decibels between 80 kilohertz (kHz) and 450 megahertz (MHz).

[0079] 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 via one or more ADCs 220.

[0080] In some embodiments, modulators 204A and / or modulators 204B may have a bandwidth between 400 MHz and 1000 MHz.

[0081] 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 via transmitter 216. Optical system 210 may be 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 in the RX path via receiver 222. 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 in the RX path. Mixer 208 may be configured to pair (e.g., connect, link, identify, etc.) a first return optical signal and a first modulated LO signal, mix (e.g., combine, multiply, etc.) the first return optical signal and the first modulated LO signal to generate a first downconverted signal, and transmit the first downconverted signal to detector 212. Similarly, mixer 208 may be configured to pair a second return optical signal and a second modulated LO signal, mix the second return optical signal and the second modulated LO signal to generate a second downconverted signal, and transmit the second downconverted signal to detector 212. Detector 212 may be configured to generate first and second electrical signals based on the first and second downconverted 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 and ADC 220.

[0082] Figure 3 shows a high-level block diagram illustrating exemplary components 302, 304, 306, and 308 of a modular LIDAR sensor system 300 for an autonomous vehicle according to one embodiment. According to one embodiment, the modular LIDAR sensor system 300 includes a seed laser 308, a modular modulator 306, a modular amplifier 304, and a modular transceiver chip 302. As previously stated, the modular LIDAR sensor system 300 is particularly advantageous because its modular design allows each of the components 302, 304, 306, and 308 to be a separate integrated circuit optically coupled by microlenses. This provides a high yield of the modular components 302, 304, 306, and 308 and ease of configuration and assembly for various variations of each modular component 302, 304, 306, and 308. Such a modular architecture is particularly advantageous because the seed laser 308, modular modulator 306, modular amplifier 304, and modular transceiver chip 302 can each be configured and tested separately before being assembled into the configuration described later with reference to Figures 4 and 5. Essentially, the modular architectures in Figures 3, 4, and 5 consist only of individual integrated circuits and microlenses. Such a modular architecture does not require any optical fibers to optically couple the components of the modular architecture.

[0083] A seed laser 308 is provided to generate a light beam. In some embodiments, the seed laser 308 may be a light source, such as a dispersion feedback (DFB) diode laser source. The light or beam from the seed laser 308 may be optically coupled for input to a modular modulator 306. In some embodiments, the seed laser 308 includes a DFB diode laser source 310 and a microlens assembly 312 that couples the DFB diode laser source 310 to the modular modulator 306. The seed laser 308 is modular in that it can be configured as a single integrated circuit.

[0084] The modular modulator 306 receives the optical beam generated by the seed laser and generates a modulated optical signal. In some embodiments, the modular modulator 306 includes a modulator and a splitter (see Figures 4 and 5 below). In some embodiments, the modular modulator 306 performs in-phase and quadrature modulation to generate the modulated beam. In some embodiments, the modular modulator 306 performs phase modulation to generate the modulated beam. The splitter is coupled to the output of the modulator and provides the output of the modular modulator 306. In some embodiments, the splitter is a single splitter, which is a passive component that is hybrid-integrated with the modulator of the modular modulator 306, as described in more detail below with reference to Figure 4. In some embodiments, the splitter is multiple splitters, as described in more detail below with reference to Figure 5. The modular modulator 306 is modular in that it can be configured as a single integrated circuit.

[0085] In some embodiments, the seed laser 308 and the modular modulator 306 may be integrated to form a seed laser assembly 314. In some embodiments, the seed laser assembly 314 is mounted on a first submount, and the coupled modular transceiver chip 302 is mounted on a second submount to align the height of the seed laser assembly 314 with the height of the modular transceiver chip 302 for optical coupling.

[0086] The modular amplifier 304 is one or more semiconductor optical amplifiers (SOAs). In some embodiments, the modular amplifier 304 is one or more tapered semiconductor optical amplifiers (TSOAs). In some embodiments, the modular amplifier 304 is one or more SOA array chips. Each SOA array chip includes an integrated U-turn and other passive components for optical amplification. In some embodiments, the SOA array chip may be an Integrated Photonic Device based on III-V semiconductors, where all components are formed from III-V materials and formed / displaced on a single substrate formed from III-V materials. Furthermore, in some embodiments, each SOA array chip may include four to five channels and may be configured to amplify a beam by stimulated emission. The modular amplifier 304 is optically coupled to a modular modulator 306 by microlenses (not shown). Similarly, the modular amplifier 304 is optically coupled by microlenses (not shown) to provide the amplified signal to a modular transceiver chip 302. Details of this optical coupling will be explained in more detail below with reference to Figures 4 and 5.

[0087] In some embodiments, the modular silicon photonics (SiPho) transceiver chip 302 includes at least one of a silicon photonics circuit, a programmable logic controller (PLC), or a III-V semiconductor circuit. The modular SiPho transceiver chip 302 processes the coupled light using a modular amplifier 304. The modular SiPho transceiver chip 302 includes a plurality of coherent pixels that process the output of the modular amplifier 304 and emit light from the surface of the modular SiPho transceiver chip 302 through an optical window of the integrated chip packaging. The modular SiPho transceiver chip 302 processes the light collected by reflection from a target and couples the detected photocurrent to a transimpedance amplifier (not shown). The transimpedance amplifier converts the photocurrent into an electrical voltage, which is then coupled to the outside of the integrated chip packaging.

[0088] Figure 4 is a high-level block diagram showing exemplary modular components of a horizontally integrated LiDAR sensor system 400 for an autonomous vehicle according to one embodiment. As shown, the LiDAR sensor system 400 includes a seed laser 308, a modular modulator 306, an integrated seed microlens 402, a splitter 404, a first microlens array 406a, an array of TSOA 408, a second microlens array 406b, and a modular SiPho transceiver chip 302.

[0089] In this embodiment, the seed laser 308, modular modulator 306, and modular SiPho transceiver chip 302 have the same structure, form, and function as those described above with reference to Figure 3, and therefore will not be described again here. The modular modulator 306 is coupled to the splitter 404 by an integrated seed microlens 402. That is, the seed laser 308, modular modulator 306, and integrated seed microlens 402 can be integrated into a single integrated circuit. An exemplary configuration for such integration is shown in Figure 4 as a cross-sectional view of the p-up semiconductor structure to the left of components 306, 308, and 402.

[0090] The splitter 404 is a one-to-n splitter that divides the optical signal output to the splitter 404 via the integrated seed microlens 402 by the modular modulator 306 into n signals. In some embodiments, the core pitch of the splitter 404 is in the range of 450 to 550 micrometers. In some embodiments, the splitter 404 is a one-to-16 splitter with a core pitch of 500 μm. In some embodiments, the splitter 404 is a one-to-32 splitter with a core pitch of 500 μm. In some embodiments, the splitter 404 is a passive optical splitter. In some embodiments, the splitter 404 is formed on one or more integrated circuits. An exemplary configuration for such integration is shown in Figure 4 as a cross-sectional view of the p-down semiconductor structure to the left of components 402 and 404.

[0091] The first microlens array 406a is used to optically couple the output of the splitter 404 to the array of TSOA 408. The first microlens array 406a includes a microlens for each signal output by the splitter 404. In some embodiments, the first microlens array 406a includes 16 microlenses having a 500 μm pitch. In some embodiments, the first microlens array 406a includes 32 microlenses having a 500 μm pitch. Each lens of the first microlens array 406a couples the output of the splitter 404 to the corresponding TSOA of the array of TSOA 408. In some embodiments, the seed microlens 402 and the lens array of the first microlens array 406a compensate for the height difference between the first height of the submount of the modular modulator 306 and the second height of the submount of the modular amplifier 408.

[0092] An array of TSOA408s has the same number of TSOAs as the output signals of the splitter 404; that is, there is one corresponding TSOA for each signal output by the splitter 404. In some embodiments, the splitter 404 outputs 16 optical signals, and the array of TSOA408s contains 16 TSOAs. In some embodiments, the splitter 404 outputs 32 optical signals, and the array of TSOA408s contains 32 TSOAs. In some embodiments, the array of TSOA408s contains 16 aperture bars or a number of individual bars, the array containing 16 TSOAs. As described below, the array of TSOAs includes real estate for bi-sided cooling and flatness. In some embodiments, the TSOAs have a pitch of 500 μm. In other embodiments, it should be understood that the array may be of a different type of SOA. The TSOA408 array is optically coupled to the splitter 404 by the first microlens array 406a and optically coupled to the modular SiPho transceiver chip 302 by the second microlens array 406b.

[0093] The second microlens array 406b is used to optically couple the output of the TSOA408 array to the modular SiPho transceiver chip 302. The second microlens array 406b includes a microlens for each signal output by the TSOA408 array. Essentially, the second microlens array 406b includes a microlens for each TSOA in the TSOA408 array. In some embodiments, the second microlens array 406b includes 16 microlenses having a 500 μm pitch. In some embodiments, the second microlens array 406b includes 32 microlenses having a 500 μm pitch. Each lens of the second microlens array 406b couples the output of the TSOA to the corresponding input of the modular SiPho transceiver chip 302.

[0094] In some embodiments, the first microlens array 406a, the TSOA 408 array, and the second microlens array 406b are formed on a single integrated circuit. An exemplary configuration for this integration is shown in Figure 4 as a cross-sectional view of the p-down semiconductor structure with these components 406a, 408, and 406b to the left.

[0095] The modular components 306, 402, 404, 406a, 408, 406b, and 302 are horizontally integrated, meaning that each semiconductor chip forming each modular component is stacked on top of the others as shown. This requires only horizontal alignment of different components to ensure that light is transmitted from one modular component to another as needed for optical coupling. In some embodiments, the optical ports of the two aligned chips should be on the same pitch and have matching optical mode sizes and cross-sectional angles according to Snell's Law.

[0096] Figure 5 is a high-level block diagram showing exemplary modular components of a horizontally or vertically integrated LiDAR sensor system 500 for an autonomous vehicle according to some embodiments. The LiDAR sensor system 500 includes a seed laser 308, a modular modulator 306, multiple seed microlenses 502a-502d, multiple splitters 504a-50d, a first multiple microlens array 506a-506d, multiple TSOA chips 508a-508d, a second multiple microlens array 510a-510d, and a modular SiPho transceiver chip 302.

[0097] The LIDAR sensor system 500 in Figure 5 is further modularized by dividing the splitter 404 into multiple splitter chips 504a to 504b, dividing the first microlens array 406a into multiple microlens arrays 506a to 506d, dividing the TSOA chip 408 into multiple TSOA chips 508a to 508d, and dividing the second microlens array 406b into multiple microlens arrays 510a to 510d. Such a variation of the modular architecture improves yield and reliability by having components that are easier to manufacture. Such an architecture requires a vertical or horizontal alignment of an increased number of modular components to achieve the same architectural output.

[0098] In this embodiment, the seed laser 308, modular modulator 306, and modular SiPho transceiver chip 302 have the same structure, form, and function as those described above with reference to Figures 3 and 4, and therefore will not be described again here.

[0099] The modular modulator 306 is coupled to a plurality of microlenses 502a to 502d. Each of the microlenses 502a to 502d is optically coupled to a corresponding splitter 504a to 504d. For example, microlens 502a couples the modular modulator 306 to splitter 504a. Similarly, microlens 502b couples the modular modulator 306 to splitter 504b, microlens 502c couples the modular modulator 306 to splitter 504c, and microlens 502d couples the modular modulator to splitter 504c.

[0100] In some embodiments, the multiple splitters 504a to 504d are each splitter chips. For example, if an architecture similar to that in Figure 4 is required, and the modular splitter 404 is a 1-to-16 splitter, then the multiple splitters 504a to 504d are each 1-to-4 splitter chips, and therefore the four splitter chips 504a to 504d in Figure 5 can provide the same functionality as the single modular splitter 404 in Figure 4. Each of the multiple splitters 504a to 504d couples each microlens 502a to 502d to its respective microlens array 506a to 506d. For example, splitter 504a couples microlens 502a to microlens array 506a, splitter 504b couples microlens 502b to microlens array 506b, splitter 504c couples microlens 502c to microlens array 506c, and splitter 504d couples microlens 502d to microlens array 506d. Figure 5 should be understood as illustrating how any number of splitter chips with smaller splitting ratios can be used in a modular system instead of a single splitter chip with a larger splitting ratio.

[0101] As mentioned above, each splitter 504a-504d is coupled to its respective microlens array 506a-506d. In some embodiments, there are four microlens arrays 506a-506d. Continuing to compare the modular design of Figure 4 with the modular design of Figure 5, a single microlens array 406a is replaced by multiple microlens arrays 506a-506d. For example, if a single microlens 406a contains 16 microlenses with a 500 μm pitch and a similar architecture is required, each of the multiple microlens arrays 506a-506d contains four microlenses with a 500 μm pitch. In some embodiments, the number of microlens arrays and the number of microlenses within each array correspond to the number of signals generated by the splitter chips 504a-504d, respectively. Each of the multiple microlens arrays 506a-506d is coupled in sequence to provide each optical signal to its respective TSOA chip 508a-508d. For example, the microlens array 506a provides an optical signal to the TSOA chip 508a, and the microlens array 506b provides an optical signal to the TSOA chip 508b.

[0102] As shown in Figure 5, each of the multiple TSOA chips 508a-508d amplifies the optical signal received from the corresponding microlens arrays 506a-506d. In some embodiments, the design includes four TSOA chips 508a-508d. Again, continuing to compare the modular design of Figure 4 with the modular design of Figure 5, a single array of TSOA408 is replaced by multiple TSOA chips 508a-508d. In contrast to a single array of TSOA408, each of the TSOA chips 508a-508d includes four TSOAs. In some embodiments, the multiple TSOA chips 508a-508d may have 16 aperture bars or a number of individual bars, double-sided cooling, side space for flatness, and a 500 μm pitch. In other embodiments, it should be understood that the TSOA chips 508a-508d may be other types of SOA.

[0103] Each of the multiple TSOA chips 508a to 508d is optically coupled to the modular SiPho transceiver chip 302 by a corresponding microlens array 510a to 510d. The second multiple microlens arrays 510a to 510d may be similar in form and function to the first multiple microlens arrays 506a to 506d, but each of them couples to the modular SiPho transceiver chip 302. In this embodiment of the design, the number of microlens arrays 510a to 510d corresponds to the number of TSOA chips 508a to 508d.

[0104] Figure 6 shows a high-level block diagram illustrating an exemplary plan view of modular components for a LiDAR sensor system 600 for an autonomous vehicle according to some embodiments. Figure 6 shows one planar mount and layout for the modular components of the present disclosure. In some embodiments, the LiDAR sensor system 600 includes a seed laser assembly 314, a splitter 404, a modular SiPho transceiver chip 302, a plurality of semiconductor optical amplifiers 602a to 602d, and a plurality of lenses 604a to 604d. As shown, the seed laser assembly 314 inputs an optical beam to the modular components on an integrated circuit 606, which includes the splitter 404 and the modular SiPho transceiver chip 302. The integrated circuit 606 is optically coupled by a signal line 608 and provides an optical input to an optical amplifier 602d of the plurality of semiconductor optical amplifiers 602a to 602d via a lens 604d. The semiconductor optical amplifiers 602a to 602d are coupled to send and receive optical signals from each other. Furthermore, each of the multiple semiconductor optical amplifiers 602a to 602d is coupled by their respective lenses 604a to 604b to transmit the amplified signal back to the integrated circuit 606. Although not shown, the semiconductor chip 606 also includes other inputs and outputs for providing optical signals to other components. In some embodiments, the optical ports of two aligned chips should be on the same pitch and have matching optical mode sizes and cross-sectional angles according to Snell's law.

[0105] Figure 7 is a cross-sectional view showing an exemplary integrated chip packaging 700 for a modular LiDAR sensor system for an autonomous vehicle according to some embodiments. In Figure 7, the integrated chip packaging 700 for the LiDAR sensor system defines the configuration of the optical components, which provides a path for optical signals or beams to travel in and out of the integrated chip packaging 700 and for dissipating heat generated by the optical components to improve performance. The integrated chip packaging 700 may include a lid 704 covering the top surface of the integrated chip packaging 700. The integrated chip packaging 700 may include a U-shaped block 706 coupled to the lid 704, which can seal the optical components in an hermetically sealed state. For example, the U-shaped block 706 may be made of copper. The integrated chip packaging 700 may include a cooling plate 702 coupled to the side of the integrated chip packaging 700. In some embodiments, the cooling plate 702 may be coupled to the lid 704 so as to be on top of the lid 704. In other embodiments, the cooling plate 702 may be coupled to the U-shaped block 706 so as to be located beneath the U-shaped block 706 on the opposite side of the lid 704, in a manner that does not obstruct the optical window 420. The material of the cooling plate 702 may be copper, aluminum, or silicon.

[0106] The integrated chip packaging 700 may include a silicon photonic transceiver chip 712 separated from the MOB 708. The transceiver chip 712 is coupled to the MOB 708 via a micro-optical assembly 710 and configured to receive the beam output by the MOB 708. For example, the micro-optical assembly 710 may include a microlens array for collimating the beam from the MOB 708 to a coupling facet at the edge of the transceiver chip 712. The integrated chip packaging 700 may also include an assembly of a semiconductor optical amplifier (SOA) array chip 714. The SOA array chip 714 can be implemented as a III-V semiconductor module coupled to the transceiver chip 412 by hybrid integration on the upper surface of the transceiver chip 712. This hybrid integration is useful for eliminating the need for a micro-optical assembly to couple the SOA array chip 714 with the transceiver chip 712. The transceiver chip 412 is configured to process the beam received from the MOB 708. For example, the transceiver chip 712 uses one or more SOA array chips 714 to amplify the beam.

[0107] The integrated chip packaging 700 may include an optical window 720 in a U-shaped block 706 on the bottom surface opposite the lid 704 to provide an interface for optical signals. The material of the optical window 720 may be one of glass, fused silica, or an organic polymer. The optical window 720 allows the beam to move in and out of the surface-emitting transceiver chip 712. After amplifying the beam using the SOA array chip 714 assembly on the upper surface, the transceiver chip 712 is configured to emit the beam perpendicularly from the lower surface through the optical window 720. For example, the beam is emitted from the integrated chip packaging 700 perpendicular to the lower surface of the transceiver chip 712. An advantage of surface emission of the beam from the transceiver chip 712 is that the optical window 720 is easier to construct compared to edge emission from the transceiver chip 712. If the beam is emitted from the edge of the transceiver tip 712, the optical window 720 needs to be precisely aligned so that it is horizontal to the narrow edge of the transceiver tip 712. Thus, the surface emission characteristics of the transceiver tip 712 provide easy assembly and manufacturability of the integrated chip packaging 700. The transceiver tip 712 may be configured to extend laterally from the optical window 720 by a threshold offset so as to sufficiently overlap with the optical window 720 within the integrated chip packaging 700. The end of the transceiver tip 712 extending laterally from the optical window 720 may be coupled to a support structure 724 for mechanical strength. In one example, the dimensions of the optical window may be millimeters length × millimeters width. The distance between the lower surface of the transceiver tip 712 and the optical window 720 may be about X microns.

[0108] A beam emitted from the integrated chip packaging 700 may be incident on a target and reflected back to the integrated chip packaging 700 through the same optical window 720. The transceiver chip 712 is configured to receive and process the beam reflected from the target. For example, the transceiver chip 712 may constitute a photodiode and generate a photocurrent based on the reflected beam collected through the optical window 720, and transmit the photocurrent to a transimpedance amplifier (TIA) 722. In some embodiments, the integrated chip packaging 700 may include a TIA 722 integrated with the transceiver chip 712 using flip-chip bonding. The TIA 722 may be configured to convert the photocurrent into a voltage signal, which is then coupled to the outside of the integrated chip packaging 700 via a wire bond 728. In some embodiments, the integrated chip packaging 700 may include a TIA 722 on the surface of the chip carrier outside the transceiver chip 712 and couple it to the transceiver chip 712. In other embodiments, the integrated chip packaging 700 excludes the TIA722 from the packaged integration. For example, the TIA722 is located outside the integrated chip packaging 700.

[0109] In some embodiments, the integrated chip packaging 700 may include a configuration of a double-sided heat transfer assembly for radiating heat generated by the sealed components during operation and maintaining the temperature of the sealed components below a reference temperature of the cooling plate 702. In the double-sided heat transfer assembly, a first heat transfer component 718 may be coupled to the lower surface of the transceiver chip 712 so as to be positioned between the transceiver chip 712 and the metal base of the U-shaped block 706 for heat dissipation. A second heat transfer component 716 may be coupled to the exposed upper surface of the SOA array chip 714 so as to be positioned between the SOA array chip 714 and the lid 704 of the integrated chip packaging 700 for heat dissipation. For example, the heat transfer components may be thermal interface materials (e.g., aluminum nitride (AlN) ceramic, beryllium oxide ceramic, pyrolysis graphite sheet (PGS), etc.), thermoelectric coolers (TEC), liquid cooling systems, or a combination thereof. In the example in Figure 7, the first heat transfer component 718 may be a thermoelectric cooler or aluminum nitride ceramic. The second heat transfer component 716 may include, for example, a first thermal interface material layer such as an AlN-n clamp bonded to the exposed surface of the SOA array chip 714, and a second thermal interface material layer such as PGS bonded to the top of the first layer. The second heat transfer component 718 may have any suitable height. The second heat transfer component 718 reduces the divergence of light radiated from the lower surface of the transceiver chip 712 through the optical window 720. The combination of a small optical window 720 and a low-height second heat transfer component 718 induces a large area beneath the transceiver chip 712 that is covered by the second heat transfer component 718 for effective heat dissipation.

[0110] The detailed description of the Disclosure set forth herein is provided for illustrative and explanatory purposes only. It is not intended that the Disclosure is complete or that it is limited to the disclosed form only. Many modifications and variations are possible in light of the preceding teachings. The embodiments described herein have been selected to best illustrate the principles of the Disclosure and their practical application, and have therefore been selected to allow those skilled in the art to best utilize the Disclosure through various modifications suited to the specific uses considered in the various embodiments. The scope of the Disclosure is intended to be defined by the claims appended herein.

[0111] While some embodiments and their advantages of this disclosure are described in detail, it should be understood that various modifications, substitutions, and changes are possible without departing from the spirit and scope of this disclosure as defined by the appended claims. For example, it will be readily apparent to those skilled in the art that many of the features, functions, processes, and materials described herein can be modified within the scope of this disclosure. Furthermore, the scope of this disclosure is not intended to be limited to any specific implementation of the processes, machines, manufactures, material compositions, means, methods, and steps described herein. As will be readily apparent to those skilled in the art from the description of this disclosure, existing or future-developed processes, machines, manufactures, material compositions, means, methods, and steps can perform substantially the same functions or achieve substantially the same results as such implementations described herein in accordance with this disclosure. Accordingly, the appended claims are intended to include such processes, machines, manufactures, material compositions, means, methods, or steps within their scope.

Claims

1. A light detection and distance measurement (LIDAR) system, A seed laser configured to output a beam, A modular modulator configured to receive a beam output from the seed laser and modulate the beam to generate a modulated beam, A modular amplifier configured to receive the modulated beam from the modular modulator and generate an amplified beam—the modular amplifier includes an array of a specific number of semiconductor optical amplifiers having a plurality of apertures for outputting the amplified beam— A light detection and distance measurement (LIDAR) system comprising: a modular transceiver chip coupled to the modular modulator and the modular amplifier; the modular transceiver chip is configured to emit the amplified beam perpendicularly from its radiating surface via surface radiation through an optical window, and to receive the beam reflected from a target through the optical window.

2. The LIDAR system according to claim 1, wherein the seed laser is a laser having a lattice structure that provides optical feedback for outputting the beam.

3. The LIDAR system according to claim 2, wherein the seed laser includes a lens array comprising a plurality of lenses that couple the beam to the modular modulator, the plurality of lenses having a pitch in the range of 450 to 550 micrometers.

4. The LiDAR system according to claim 1, wherein the modular modulator performs in-phase and quadrature modulation to generate the modulated beam.

5. The LiDAR system according to claim 1, wherein the modular modulator performs frequency modulation to generate the modulated beam.

6. The LiDAR system according to claim 1, wherein the modular modulator and the seed laser are integrated into a single chip.

7. The LIDAR system according to claim 6, wherein the seed laser is mounted on a first submount, and the modular transceiver chip coupled to the modular modulator is mounted on a second submount for aligning the height of the seed laser with the height of the modular transceiver chip for optical coupling.

8. The LIDAR system according to claim 1, wherein the semiconductor optical amplifiers in the array of the specified semiconductor optical amplifiers are integrated with U-shaped passive components for optical amplification.

9. The LIDAR system according to claim 1, wherein the modular amplifier includes a tapered semiconductor optical amplifier configured to receive the modulated beam from the modular modulator and generate the amplified beam by stimulated emission.

10. The LIDAR system according to claim 1, wherein the modular amplifier comprises one of indium phosphide (InP), gallium arsenide (GaAs), indium arsenide (InAs), gallium nitride (GaN), indium antimonide (InSb), or a rare earth doped material.

11. The LIDAR system according to claim 1, wherein the particular semiconductor optical amplifier comprises additional material on its side for bow management.

12. The Lidar system according to claim 1, wherein the modular amplifier includes a first bar attached to a first part of the modular amplifier and a second bar attached to a second part of the modular amplifier, the second bar having a coefficient of thermal expansion that matches the coefficient of thermal expansion of the first bar, and the first bar and the second bar are configured to lower the junction temperature of the modular amplifier.

13. The LIDAR system according to claim 1, wherein the modular modulator is optically coupled to the modular amplifier by a lens array.

14. The LIDAR system according to claim 13, wherein the lens array compensates for the height difference between the first height of the submount of the modular modulator and the second height of the submount of the modular amplifier.

15. The LIDAR system according to claim 1, further comprising a splitter that couples the modular modulator to the modular amplifier, wherein the splitter comprises a 1-to-16 splitter having a pitch in the range of 450 to 550 micrometers.

16. The system further includes a lens array that couples the modular modulator to the modular amplifier, and a splitter that includes a plurality of 1-to-4 splitter chips having a pitch in the range of 450 to 550 micrometers. The LIDAR system according to claim 1, wherein the lens array comprises four lenses and has a pitch in the range of 450 to 550 micrometers.

17. The LIDAR system according to claim 1, wherein the semiconductor chips corresponding to the modular modulator, the modular amplifier, and the modular transceiver chip are horizontally aligned along a direction perpendicular to the radiation direction of the amplified beam.

18. The LIDAR system according to claim 1, wherein the semiconductor chips corresponding to the modular modulator, the modular amplifier, and the modular transceiver chip are aligned perpendicularly along the radiation direction of the amplified beam.

19. The LIDAR system according to claim 1, wherein the modular modulator, the modular amplifier, and the modular transceiver chip are part of an autonomous vehicle.

20. The LIDAR system according to claim 1, wherein the modular modulator, the modular amplifier, and the modular transceiver chip are part of an autonomous vehicle control system.

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