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 relates generally 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 technology]

[0002] LIDAR sensor systems are used in a variety of applications, ranging from altitude measurement to imaging and collision avoidance. LIDAR sensor systems can be designed and implemented using integrated photonic circuits (PICs), or integrated optical circuits, which are chips containing photonic components. In the past, there have been attempts to integrate more of a LIDAR system's photonic components into a single PIC. However, these attempts have been problematic due to their complexity and the significant yield losses that occur during the manufacture of these complex chips. Another prior art approach has been to use fiber optic connectors to couple the various components of a LIDAR system. The drawbacks of using fiber optic cable connectors are the additional space required, as well as the configuration complexity and alignment issues that arise when using optical fibers and connectors. Therefore, there is a need for a method to build LIDAR systems with higher yields and reduced complexity. Summary of the Invention

[0003]

[0001] Embodiments of the present disclosure relate to a modular architecture for a vehicle Light Detection and Ranging (LIDAR) sensor system, and more particularly, to a LIDAR sensor system comprised of modular components and a method for configuring the components for cooperation and communication. According to one aspect of the subject matter described in this disclosure, 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 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 including a specific semiconductor optical amplifier having multiple apertures, and a modular transceiver chip coupled to the modular modulator and the modular amplifier, the transceiver chip configured to emit the beam perpendicular to a first surface of the transceiver chip through an optical window and receive the beam reflected from an object through the optical window.

[0004] These and other embodiments may each optionally include one or more of the following features. For example, the features may include a seed laser including a laser with a grating structure providing optical feedback to output a beam, or a lens, the lens having a pitch in the range of 450 to 550 micrometers, that couples the beam to the modular modulator. For example, the features may also include the modular modulator performing in-phase and quadrature modulation or frequency modulation to generate the modulated beam. In other examples, the features may include the modular modulator and seed laser being integrated into a single chip to form a seed laser assembly. In other features, the seed laser assembly is mounted on a first submount, and the modular transceiver chip coupled to the modular modulator is mounted on a second submount to align 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 the modulated beam from the modular modulator and generate an amplified beam by stimulated emission. For example, in one embodiment, the modular amplifier includes 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 the particular semiconductor optical amplifier having an additional material for bow management on its side surface. Furthermore, the feature may further include the modular amplifier including a first bar attached to a first portion of the modular amplifier and a second bar attached to a second portion of the modular amplifier, where the second bar has a thermal expansion coefficient matching that of the first bar, and the first bar and the second bar are configured to reduce a junction temperature of the modular amplifier, or the first and second bars are 16 aperture bars, and the modular amplifier includes 16 tapered semiconductor optical amplifiers.For example, the feature may include a modular modulator optically coupled to the modular amplifier by a lens array, or the lens array may compensate for a height difference between a first height of a submount of the modular modulator and a second height of a submount of the modular amplifier. The feature may also include a feature in which the modular modulator, modular amplifier, and modular transceiver chips are fully tested before integration, enabling high yields. Another feature may include a splitter coupling the modular modulator to the modular amplifier, the splitter including a 1-to-16 splitter having a pitch in a range of 450 to 550 micrometers. For example, the feature may include a lens array coupling the modular modulator to the modular amplifier, and a splitter including a plurality of 1-to-4 splitter chips having a pitch in a range of 450 to 550 micrometers, where the lens array includes four lenses and has a pitch in a range of 450 to 550 micrometers. Further, features may include features where the modular modulator, modular amplifier, and modular transceiver chips are horizontally integrated or vertically integrated. Further, features may include features where the modular modulator, modular amplifier, and modular transceiver chips are part of an autonomous vehicle or part of an autonomous vehicle control system.

[0005] According to another aspect of the subject matter described in this disclosure, a LIDAR sensor system for a vehicle includes a seed laser configured to output a beam, a modulator coupled to the seed laser to receive the 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 configured to process and emit the amplified beam in a predetermined direction relative to the transceiver by surface emission and to receive and process the beam reflected from an object in an environment in which the vehicle is located. In some embodiments of the present disclosure, an autonomous vehicle control system may include one or more processors configured to determine at least one of a distance to an object or a velocity of the object using the LIDAR sensor system described herein and the reflected beam, and control operation of the autonomous vehicle in response to at least one of the distance or velocity. In some embodiments of the present disclosure, an autonomous vehicle may include a 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 the reflected beam to determine at least one of a distance to an object or a velocity of the object, and to control 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 and other embodiments may each optionally include one or more of the following features. For example, the feature may include a transceiver including an optical window through which the amplified beam is emitted and the reflected beam is received. The feature may also include surface emission, including emitting the amplified beam perpendicularly from a surface of the transceiver. For example, the feature may also include the transceiver processing the beam reflected from the object to detect a photocurrent and coupling the detected photocurrent to a transimpedance amplifier. In another example, the feature may include the modulator and seed laser integrated into a seed laser assembly, the seed laser assembly mounted on a first submount, and the transceiver mounted on a second submount for aligning the height of the seed laser and the height of the transceiver for optical coupling. In another example, the feature may include the amplifier including a semiconductor optical amplifier, the semiconductor optical amplifier integrated with U-shaped passive components for optical amplification. In another example, the feature may include the amplifier including a tapered semiconductor optical amplifier configured to receive the modulated beam from the modulator and generate the amplified beam by stimulated emission of light. 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 a rare-earth doped material. For example, features may include: a modulator optically coupled to the amplifier via a first lens array, the first lens array compensating for a height difference between a first height of a submount of the modulator and a second height of a submount of the amplifier; and the amplifier optically coupled to the transceiver via a second lens array. In one example, the first lens array, the amplifier, and the second lens array are integrated onto a single chip. In another example, features may include a splitter coupling an output of the modulator to an input of the amplifier, the splitter including a 1-to-16 splitter having a pitch ranging from 450 to 550 micrometers.In another example, the feature may also include a first lens array coupling the output of the splitter to the input of the amplifier, the splitter including a plurality of 1-to-4 splitter chips having a pitch in the range of 450 to 550 micrometers, the first lens array including four lenses and having a pitch in the range of 450 to 550 micrometers.Further, the feature may include a feature in which each of the modulator, amplifier, and transceiver is modular and horizontally aligned for optical coupling, and the optical ports of each of the modulator, amplifier, and transceiver horizontally aligned for optical coupling have matching pitches, matching optical mode sizes, and matching facet angles.In another example, the feature may include a feature in which each of the modulator, amplifier, and transceiver is modular and vertically aligned for optical coupling.

[0007] Those skilled in the art will appreciate that this Summary is illustrative only and is not intended to be limiting in any way. Any of the features described herein may be used with other features, and any subset of such features may be used in combination, according to various embodiments. Other aspects, inventive features, and advantages of the apparatus and / or processes described herein, as defined solely by the claims, will become apparent from the detailed description disclosed herein in conjunction with the accompanying drawings. Additionally, the language used in this disclosure has been chosen primarily for readability and descriptive purposes, and not to limit the scope of the subject matter disclosed herein. [Brief explanation of the drawings]

[0008] Some embodiments in the accompanying drawings are provided by way of example, and not by way of limitation, and like reference numerals refer to similar elements.

[0009] [Figure 1a] 1 is a block diagram illustrating an example of an autonomous vehicle system environment in accordance with some embodiments.

[0010] [Figure 1b]1 is a block diagram illustrating an example system environment for an autonomous commercial truck vehicle, according to some embodiments.

[0011] [Figure 1c] 1 is a block diagram illustrating an example system environment for an autonomous commercial truck vehicle, according to some embodiments.

[0012] [Figure 1d] 1 is a block diagram illustrating an example system environment for an autonomous commercial truck vehicle, according to some embodiments.

[0013] [Figure 2] FIG. 1 is a block diagram illustrating an example of a LIDAR sensor system for an autonomous vehicle, according to some embodiments.

[0014] [Figure 3] FIG. 1 is a high-level block diagram illustrating example components of a LIDAR sensor system for an autonomous vehicle in accordance with some embodiments.

[0015] [Figure 4] FIG. 1 is a high-level block diagram illustrating example modular components of a horizontally integrated LIDAR sensor system for an autonomous vehicle, according to some embodiments.

[0016] [Figure 5] FIG. 1 is a high-level block diagram illustrating example modular components of a horizontally or vertically integrated LIDAR sensor system for an autonomous vehicle, according to some embodiments.

[0017] [Figure 6] FIG. 1 is a high-level block diagram illustrating an example floor plan of modular components of a LIDAR sensor system for an autonomous vehicle, according to some embodiments.

[0018] [Figure 7]1 illustrates a cross-sectional view of 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 may be used without departing from the principles described herein. DETAILED DESCRIPTION OF THE INVENTION

[0020] According to certain embodiments, 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 of the components is a separate integrated circuit, optically coupled by microlenses. This modularity allows the modular LIDAR sensor system 300 to overcome the aforementioned drawbacks of the prior art because each separate integrated circuit has a much higher yield than each of the modular components. This modular design allows each component to be individually tested for various aspects of its effectiveness. Furthermore, this modular design also provides greater configuration flexibility because different versions of any of the modular modulator 306, modular amplifier 304, or modular transceiver chip 302 configurations can be used with other modular components. In some embodiments, the LIDAR sensor system 300 may also include integrated chip packaging for the LIDAR sensor that provides a path for optical signals to travel in and out of the LIDAR sensor and defines a configuration of the optical components to dissipate heat generated by the optical components for improved performance. The modular transceiver chip 302 may be configured to emit a beam normal to 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 purposes of explanation, numerous specific details are presented in order to provide a thorough understanding of the various aspects of various exemplary embodiments. It should be noted that certain exemplary embodiments may be practiced in various cases without all of the specific details and / or by variations, substitutions, and combinations of the various features and elements described herein. Reference will now be made in detail to embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.

[0022] Additionally, relative terms such as "bottom" or "lower" or "back" or "below" and "top" or "upper" or "front" or "top" may be used herein to describe the relationship of one element to other elements, as depicted in the figures. It will be understood that the relative terms are intended to include other orientations of the device in addition to the orientation depicted in the figures. For example, if a device in one of the figures were turned over, an element described as being "below" the other elements would then be "above" the other elements. Thus, the exemplary term "lower" can encompass both an orientation of "lower" and "upper," depending on the particular orientation of the figure. Similarly, if a device in one of the figures were turned over, an element described as being "below" or "bottom" the other elements would then be "above" the other elements. Thus, the exemplary terms "lower" or "lower" can encompass both an orientation of up and down.

[0023] Referring to the drawings, in which like numbers indicate like parts in some figures, FIG. 1a illustrates one embodiment of a system environment 100A for an autonomous vehicle 111A in which various techniques disclosed herein may be implemented. For example, the vehicle 111A may include a powertrain 102 including a prime mover 104 driven by an energy source 106 and capable of powering a drivetrain 108, and a control system 110 including directional control 112, powertrain control 114, and brake control 116. It should be appreciated that the vehicle 111A may be implemented as any number of different types of vehicles, including vehicles capable of transporting people and / or cargo and traveling on land, and that the components 102-116 described above may vary significantly depending on the type of vehicle in which these components are utilized.

[0024] For simplicity, the embodiments discussed below focus on wheeled land vehicles such as cars, vans, trucks, and buses. In such embodiments, prime mover 104 may include (among other things) one or more electric motors and / or internal combustion engines. 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. Drivetrain 108 may include wheels and / or tires along with a transmission and / or any other mechanical drive components for converting the power output of prime mover 104 into vehicle motion, one or more brakes configured to controllably stop or slow vehicle 111A, and a steering or steering component suitable for controlling the trajectory of vehicle 111A (e.g., a rack and pinion steering linkage that allows the wheels to pivot about a generally vertical axis to change the angle of the plane of rotation of the wheels relative to the vehicle's longitudinal axis). In some embodiments, a combination of powertrain and energy source can be used (e.g., in the case of electric / gas hybrid vehicles), and in other embodiments, multiple electric motors (e.g., dedicated to individual wheels or axles) can be used as prime mover 104. In the case of a hydrogen fuel cell implementation, prime mover 104 can include one or more electric motors, and energy source 106 can include a fuel cell system powered by hydrogen fuel.

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

[0026] Other vehicle types, including, but not limited to, all-terrain or tracked vehicles, construction equipment, and the like, may utilize different powertrains, drivetrains, energy sources, directional control, powertrain control, and braking control. Also, in some embodiments, some of the components may be combined; for example, vehicle directional control is primarily handled by modifying the output of one or more prime movers. Accordingly, the embodiments described herein are not limited to the specific application of the technology described herein in autonomous wheeled land vehicles.

[0027] In the illustrated embodiment, various levels of autonomous control, including fully or semi-autonomous control, for vehicle 111A may be implemented in vehicle control system 120, which may include one or more processors 122 and one or more memories 124, each processor 122 configured to execute program code instructions 126 stored in memory 124. The processors may include, for example, graphics processing units (GPU(s)) and / or central processing units (CPU(s)).

[0028] The sensors 130 may include various sensors suitable for collecting information from the vehicle's surrounding environment for use in controlling the operation of the vehicle 111A. For example, the sensors 130 may include one or more detection and ranging sensors (e.g., a RADAR sensor 134 and / or a LIDAR sensor 136), a 3D positioning sensor 138, and a satellite navigation system such as the Global Positioning System (GPS), Globalnaya Navigazionnaya Sputnikovaya Sistema (GLONASS), or Global Navigation Satellite System (GLONASS), the 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. The sensors 130 may optionally include a camera 140 and / or an inertial measurement device (IMU) 142. The camera 140 may be a monographic or stereographic camera and may record still and / or video images. The IMU 142 may include multiple gyroscopes and accelerometers capable of detecting linear and rotational motion of the vehicle 111A in three directions. One or more encoders 144, such as wheel encoders, may 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 photonics device structure for a coherent LIDAR system, as described in more detail below.

[0029] The outputs of the sensors 130 may be provided to a series of control subsystems 150, including a position estimation subsystem 152, a perception subsystem 154, a planning subsystem 156, and a control subsystem 158. The position estimation subsystem 152 may primarily perform functions such as precisely determining the position and orientation (also sometimes referred to as “pose” or “pose estimation”) of the vehicle 111A within the surrounding environment and generally within some reference frame. The perception subsystem 154 may primarily perform functions such as detecting, tracking, and / or identifying objects within the vehicle 111A's environment. Machine learning models, according to some embodiments, may be utilized to track the objects. The planning subsystem 156 may primarily perform functions such as planning a movement trajectory or path for the vehicle 111A over some time frame given a desired destination as well as static and moving objects within the environment. Machine learning models, according to some embodiments, may be utilized to plan the vehicle trajectory. The control subsystem 158 may primarily perform functions such as generating appropriate control signals to control various controls within the vehicle control system 120 to implement the planned trajectory of the vehicle 111A. Similarly, a machine learning model can be utilized to generate one or more signals for controlling the autonomous vehicle 111A to implement a planned trajectory.

[0030] It will be understood that the collection of components for vehicle control system 120 shown in FIG. 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 FIG. 1a may be used for redundancy 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, while subsystems 152-158 are shown as separate from processor 122 and memory 124, it should be understood that in some embodiments, some or all of the functionality of subsystems 152-158 may be implemented as program code instructions 126 resident in one or more memories 124 and executed by one or more processors 122, and that these subsystems 152-158 may, in some cases, be implemented using the same processor and / or memory. The subsystems may 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, etc., and as previously mentioned, multiple subsystems may utilize circuits, processors, sensors, and / or other components. Additionally, the various components of vehicle control system 120 may be networked in various ways.

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

[0032] In general, the various components shown in FIG. 1a can be implemented using many different architectures, including various combinations of software, hardware, circuit logic, sensors, and networks. Each processor can be implemented, for example, as a microprocessor, and each memory can include not only random access memory (RAM) devices constituting main storage, but also any secondary levels 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, as well as any storage capacity used as virtual memory, such as stored in a mass storage device or other computer controller. One or more of the processors 122 shown in FIG. 1a, or entirely separate processors, can be used to implement additional functions within the vehicle 111A other than those for autonomous control, such as controlling the entertainment system, operating doors, lighting, convenience functions, etc.

[0033] Also, for additional storage devices, vehicle 111A may include one or more mass storage devices, such as, among others, a removable disk drive, a hard disk drive, a direct access storage device (DASD), an optical drive (e.g., a CD drive, a DVD drive, etc.), a solid state storage drive (SSD), network attached storage, a storage area network, and / or a tape drive.

[0034] Vehicle 100 may also include a user interface 118, such as one or more displays, touchscreens, voice and / or gesture interfaces, buttons and other tactile controls, etc., that enable 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 an app or web interface on another computer or electronic device, such as a mobile device.

[0035] Vehicle 111A may also include one or more network interfaces, such as network interface 162, suitable for communication with one or more networks 176 to enable communication with other computers and electronic devices, including, for example, a central service, such as a cloud service, through which vehicle 111A receives information including trained machine learning models and other data for use in its autonomous control. One or more networks 176 may be, for example, a communications network and may include a wide area network (“WAN”) such as the Internet, one or more local area networks (“LAN”) such as a Wi-Fi LAN or a mesh network, and one or more bus subsystems. One or more networks 176 may optionally utilize one or more standard communications technologies, protocols, and / or inter-process communication technologies. In some embodiments, data collected by one or more sensors 130 may be uploaded via network 176 to computing system 172 for further processing. In the illustrated embodiment, vehicle 111A may communicate with computing system 172 via network 176 and signal line 178. In some embodiments, computing system 172 is a cloud-based computing device. Further processing of autonomous vehicle data by computing system 172 according to many embodiments is described with reference to FIG. 2.

[0036] 1a and the various additional controllers and subsystems disclosed herein generally operate under the control of an operating system and execute or rely on various computer software applications, components, programs, objects, modules, data structures, etc., as described in more detail below. Additionally, the various applications, components, programs, objects, modules, etc. may also execute on one or more processors of other computers (e.g., computing system 172) coupled to vehicle 100 via network 176, for example, in a distributed, cloud-based, or client-server computing environment in which the processing required to implement the functionality of a computer program may be allocated across multiple computers and / or services via the network.

[0037] In general, the routines executed to implement the various embodiments described herein are referred to herein as "program code," whether implemented as part of an operating system or a specific application, component, program, object, module, or sequence of instructions, or a subset thereof. Program code typically resides at different times in various memory and storage devices and comprises one or more instructions that, when read and executed by one or more processors, perform the steps necessary to perform the steps or elements embodying various aspects of the present disclosure. Also, while the embodiments are described in the context of fully functional computers and systems, it should be understood that the various embodiments described herein are capable of being distributed as program products in various forms, and that the embodiments may be implemented independently of the particular type of computer-readable medium used to actually accomplish such distribution.

[0038] Examples of computer-readable media include tangible, non-transitory media such as volatile and non-volatile memory devices, floppy and other removable disks, solid-state drives, hard disk drives, magnetic tape, and optical disks (e.g., CD-ROMs, DVDs, etc.), among others.

[0039] Additionally, various program code described below may be identified based on the application for which it is embodied in a particular embodiment. However, any particular program nomenclature below is used merely for convenience, and thus the present disclosure should not be limited to use with only any particular application identified and / or implied by such nomenclature. Furthermore, given the generally infinite number of ways in which computer programs can be organized into routines, procedures, methods, modules, objects, etc., and the various ways in which program functionality may be allocated among the various software layers (e.g., operating system, libraries, APIs, applications, applets, etc.) resident within a typical computer, it should be understood that the present disclosure is not limited to the specific structure and allocation of program functionality described herein.

[0040] The exemplary environment illustrated in Figure 1a is not intended to limit the embodiments disclosed herein, and in fact, other alternative hardware and / or software environments may 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 FIG. 1a, LIDAR sensor system 201 in FIG. 2, etc.). In some embodiments, the LIDAR system may 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 a return signal reflected from an object, a frequency modulation (FM) LIDAR system can determine the object's location or precisely measure the object's velocity using the Doppler effect. FM LIDAR systems can use continuous wave (referred to as "FMCW LIDAR" or "coherent FMCW LIDAR") or quasi-continuous wave (referred to as "FMQW LIDAR"). The LIDAR system may 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 may offer significant advantages over conventional LIDAR systems for automotive and / or commercial truck applications. First, in some cases, an object (e.g., a pedestrian wearing dark clothing) may have low reflectivity, in that it reflects only a small amount (e.g., 10% or less) of the incident light incident on the object back to the FM or PM LIDAR system's sensor (e.g., sensor 130 in FIG. 1a). In other cases, an object (e.g., a shiny road sign) may have high reflectivity (e.g., 10% or more), in that it reflects a large amount of the incident light incident on the object back to the FM LIDAR system's sensor.

[0043] Regardless of the object's reflectivity, FM LIDAR systems can detect (e.g., classify, recognize, locate, etc.) objects at greater distances (e.g., twice as far) than conventional LIDAR systems. For example, FM LIDAR systems can detect low-reflectivity objects at distances of over 300 meters and high-reflectivity objects at distances of over 400 meters.

[0044] To achieve this improved detection capability, FM LIDAR systems can use sensors (e.g., sensor 130 in FIG. 1a). In some embodiments, these sensors can be sensitive to single photons, meaning they can detect the smallest possible amount of light. In some applications, FM LIDAR systems can use infrared wavelengths (e.g., 950 nm, 1550 nm, etc.), but are not limited to infrared wavelength ranges (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 an FM or PM LIDAR system at infrared wavelengths, the FM or PM LIDAR system 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 their light output (and distance detection capabilities) to be limited for eye safety reasons.

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

[0046] Another advantage of FM LIDAR systems is that they provide accurate velocity information instantly for each data point. In some embodiments, velocity measurements are made using the Doppler effect, which shifts the frequency of light received from an object based on at least one of the radial velocity (e.g., the direction vector between the detected object and the sensor) or the frequency of the laser signal. For example, for speeds occurring in road conditions where speeds are 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 small enough to be difficult to detect directly 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 data received more quickly.

[0047] Instantaneous velocity calculations also make it easier for an FM LIDAR system 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 FIG. 1 a) may receive only a few return signals (e.g., optical hits) from an object 300 m away, but if the return signals provide a velocity value of interest (e.g., a vehicle closing speed of 70 mph or greater), the FM LIDAR system and / or autonomous vehicle control system can determine individual weights for the probability associated with the object.

[0048] The FM LIDAR system's quick identification and / or tracking gives the autonomous vehicle control system more time to activate the vehicle, and a better understanding of how fast an object is moving allows the autonomous vehicle control system to better plan a response.

[0049] Another advantage of FM LIDAR systems is that they have less static noise than traditional LIDAR systems. That is, traditional LIDAR systems are designed for increased light sensitivity and typically perform poorly in bright sunlight. These systems tend to be challenged by crosstalk (e.g., when sensors are confused by each other's light pulses or light beams) and self-interference (e.g., when a sensor is confused by its own previous light pulse or light beam). To overcome this drawback, vehicles using traditional LIDAR systems often require additional hardware, complex software, and / or more computing power to manage this "noise."

[0050] FM LIDAR systems, on the other hand, do not experience these types of problems because each sensor is specifically designed to respond only to its own unique light characteristics (e.g., light beams, light waves, light pulses). If the returning light does not match the timing, frequency, and / or wavelength of the originally transmitted light, the FM sensor can filter (e.g., remove, ignore, etc.) that data point. This allows FM LIDAR systems to compute (e.g., generate, derive, etc.) more accurate data with fewer hardware or software requirements, resulting in safer, smoother driving.

[0051] Finally, FM LIDAR systems are more easily scalable than traditional LIDAR systems. With more autonomous vehicles (e.g., cars, commercial trucks, etc.) on the road, vehicles powered by FM LIDAR systems will not have to face interference issues due to sensor crosstalk. FM LIDAR systems also use less optical peak power than traditional LIDAR sensors. This allows some or all of the optical components for FM LIDAR to be fabricated on a single chip, which provides unique advantages as discussed herein.

[0052] FIG. 1b is a block diagram illustrating an example of a system environment for an autonomous commercial truck fleet, according to some embodiments. The 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-haul freight transportation, regional freight transportation, intermodal freight transportation (i.e., transportation in which a road-based vehicle is used as one of multiple transportation modes to transport cargo), and / or any other road-based freight transportation application. 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 merchandise and / or agricultural products. The commercial truck 180B may include a trailer for carrying the cargo 182B, such as a flatbed trailer, a lowboy trailer, a step deck trailer, an extendable flatbed trailer, a side kit trailer, etc.

[0053] The environment 100B includes an object 111B (shown as another vehicle in FIG. 1b) within a distance range 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 of FIG. 1a, the LIDAR system 201 of FIG. 2, etc.) for determining the distance to the object 111B and / or measuring the speed of the object 111B. Although FIG. 1b shows one LIDAR system 184B mounted on the front of the commercial truck 180B, the number of LIDAR systems and the areas in which the LIDAR systems are mounted on the commercial truck are not limited to a particular number and area. The commercial truck 180B may include any number of LIDAR systems 184B (or components such as sensors, modulators, coherent signal generators, etc.) mounted on any area of ​​the commercial truck 180B (e.g., the front, back, sides, top, bottom, lower, bottom, and / or bottom) to facilitate detection of objects in any free space relative to the commercial truck 180B.

[0055] As shown, 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 commercial truck 180B.

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

[0057] Environment 100C includes object 111C (shown as other vehicles in FIG. 1c) within a distance range of (i) 30 meters or more and (ii) 150 meters or less from commercial truck 180B. As shown, LIDAR system 184B in environment 100C may be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) within a predetermined distance (e.g., 100 meters) from commercial truck 180B.

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

[0059] Environment 100D includes object 111D (shown as another vehicle in FIG. 1d) within a distance range of 150 meters or more from commercial truck 180B. As shown, LIDAR system 184B in environment 100D may be configured to detect objects (e.g., other vehicles, bicycles, trees, road signs, potholes, etc.) within a predetermined distance (e.g., 300 meters) from commercial truck 180B.

[0060] In commercial truck applications, the increased weight and correspondingly longer stopping distances required of the vehicle make it important to effectively detect objects at all distances. FM LIDAR systems (e.g., FMCW and / or FMQW systems) or PM LIDAR systems are ideally suited for commercial truck applications due to the advantages discussed above. Thus, commercial trucks equipped with these systems may have an improved ability to safely transport both people and goods over short or long distances, thereby improving the safety of not only the commercial truck but also surrounding vehicles. 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 light. 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 light to have both active and inactive portions. For example, in a 10-second period, the modulator modulates the laser light only for 8 seconds (also called the "active portion") and does not modulate the laser light for 2 seconds (also called the "inactive portion"). This allows the LIDAR system to reduce power consumption for 2 seconds because the modulator does not need to provide a continuous signal.

[0062] In the case of 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, rather than the optical signal always being on (e.g., activated, powered, transmitting, etc.). In some embodiments, the quasi-CW modulation may have a duty cycle that is greater than or equal to 1% and less than or equal to 50%. If the energy in the off state (e.g., inactivated, powered down, etc.) is dissipated during the actual measurement time, this may improve the signal-to-noise ratio (SNR) and / or reduce the signal processing requirements to consistently integrate all the energy over a longer period of time.

[0063] 2 is a block diagram illustrating an example environment for a LIDAR sensor system for an autonomous vehicle, according to some embodiments. The environment 200 includes a LIDAR sensor system 201 that includes a transmit (TX) path and a receive (RX) path. The TX path includes one or more TX input / output ports (not shown in FIG. 2), and the RX path includes one or more RX input / output ports (not shown in FIG. 2).

[0064] In some embodiments, the semiconductor substrate and / or the semiconductor package may include a TX path and / or an RX path. In some embodiments, the semiconductor substrate and / or the semiconductor package may include at least one of a silicon photonics circuit, a programmable logic controller (PLC), or a III-V semiconductor circuit.

[0065] In some embodiments, a first semiconductor substrate and / or a first semiconductor package may include a TX path, and a second semiconductor substrate and / or a 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 / disposed) along one or more edges of one or more semiconductor substrates and / or semiconductor packages.

[0066] The 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., an oscillating scanner, a unidirectional scanner, a Risley prism, a circulator optic, and / or a beam collimator, etc.) coupled to the LIDAR system 201. In some embodiments, the one or more optical systems 210 may be coupled to a TX path via one or more TX input / output ports. In some embodiments, the one or more optical systems 210 may be coupled to an RX path via one or more RX input / output ports.

[0068] The environment 200 includes a vehicle control system (e.g., vehicle control system 120 of FIG. 1a) coupled to a 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, a modulator 204A, a modulator 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). While FIG. 2 shows only a select 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 arrangement to facilitate the combination of various functions of the LIDAR system to support vehicle operation.

[0070] The laser source 202 may be configured to generate an optical signal (or beam) derived from (or related to) a local oscillator (LO) signal. In some embodiments, the optical signal may have an operating wavelength equal to or substantially equal to 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 (denoted as "RF1" in FIG. 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. The one or more transmitters 216 may include one or more optical waveguides or antennas.

[0072] The optical system 210 may be configured to steer the amplified optical signal received from the TX path toward an object 218 in the environment within a given field of view, receive a return signal reflected back from the object 218, and provide the return signal to the mixer 208 of the RX path via one or more receivers 222. The one or more receivers 222 may include one or more optical waveguides or antennas. In some arrangements, the transmitter 216 and receiver 222 may form one or more transceivers (not shown in FIG. 2). In some arrangements, the one or more transceivers may include monostatic transceivers or bistatic transceivers.

[0073] The laser source 202 may be configured to provide an LO signal to the 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 (shown as "RF2" in FIG. 2), and to send the modulated LO signal to the mixer 208 in the RX path.

[0074] 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 send the down-converted signal to the detector 212. In some arrangements, the mixer 208 may be configured to send the modulated LO signal to the detector 212.

[0075] The detector 212 may be configured to generate an electrical signal based on the down-converted signal and send the electrical signal to the TIA 214. In some arrangements, the detector 212 may be configured to generate an electrical signal based on the down-converted signal and the modulated signal.

[0076] The TIA 214 may be configured to amplify the electrical signal and transmit the amplified electrical signal to the vehicle control system 120 via one or more ADCs 220 .

[0077] In some embodiments, the TIA 214 provides 5 picowatts per square root hertz (i.e., 5×10 per square root hertz). -12 In some embodiments, the TIA 214 may have a gain between 4 kilohms and 25 kilohms.

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

[0079] The vehicle control system 120 may be configured to determine the distance to the object 218 and / or measure the velocity of the object 218 based on one or more electrical signals received from the TIA via one or more ADCs 220.

[0080] In some embodiments, modulator 204A and / or modulator 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 generate amplified optical signals for 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 an environment within a given field of view, receive corresponding first and second return signals reflected back from object 218, and provide the first and second return signals to mixer 208 of 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 of the RX path. The mixer 208 may be configured to pair (e.g., connect, link, identify, etc.) the first return optical signal and 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 the detector 212. Similarly, the mixer 208 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 down-converted signal, and transmit the second down-converted signal to the detector 212. The detector 212 may be configured to generate first and second electrical signals based on the first and second down-converted signals, respectively. The vehicle control system 120 may be configured to determine a distance to the object 218 and / or measure a velocity of the object 218 based on the first and second electrical signals received via the TIA 214 and the ADC 220.

[0082] 3 illustrates 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 some embodiments. According to some embodiments, 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 discussed, 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 individual integrated circuits optically coupled by microlenses. This provides for high yields 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 each of the seed laser 308, modular modulator 306, modular amplifier 304, and modular transceiver chip 302 can be separately configured and tested and then assembled into the configuration described below with reference to Figures 4 and 5. Essentially, the modular architectures of Figures 3, 4, and 5 include only 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, for example, a distributed feedback (DFB) diode laser source. The light or beam of the seed laser 308 may be optically coupled for input to the 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 may 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 FIGS. 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. A 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 that is a passive component hybrid-integrated with the modulator of the modular modulator 306, as described in more detail below with reference to FIG. 4. In some embodiments, the splitter is multiple splitters, as described in more detail below with reference to FIG. 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 a III-V semiconductor-based integrated photonic device in which all components are formed of III-V materials and are formed / disposed on a single substrate formed of 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 of radiation. The modular amplifier 304 is optically coupled to the modular modulator 306 by a microlens (not shown). Similarly, the modular amplifier 304 is optically coupled by a microlens (not shown) to provide an amplified signal to the modular transceiver chip 302. The details of such optical coupling are described in more detail below with reference to FIGS.

[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 multiple 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 in the integrated chip packaging. The modular SiPho transceiver chip 302 processes the collected light reflected from the target and couples the detected photocurrent to a transimpedance amplifier (not shown). The transimpedance amplifier converts the photocurrent into an electrical voltage that is then coupled externally to the integrated chip packaging.

[0088] 4 is a high-level block diagram illustrating exemplary modular components of an autonomous vehicle horizontally integrated LIDAR sensor system 400, according to some embodiments. 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 TSOAs 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 similar structure, form, and function as those described above with reference to FIG. 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 FIG. 4 as a cross-sectional view of a p-up semiconductor structure to the left of components 306, 308, 402.

[0090] Splitter 404 is a 1:n splitter that splits the optical signal output by modular modulator 306 through integrated seed microlens 402 into n signals. In some embodiments, splitter 404 has a core pitch in the range of 450-550 micrometers. In some embodiments, splitter 404 is a 1:16 splitter with a core pitch of 500 micrometers. In some embodiments, splitter 404 is a 1:32 splitter with a core pitch of 500 micrometers. In some embodiments, splitter 404 is a passive optical splitter. In some embodiments, splitter 404 is formed on one or more integrated circuits. An exemplary configuration for such integration is shown in FIG. 4 as a cross-sectional view of a 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 TSOAs 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 with a 500 μm pitch. In some embodiments, the first microlens array 406a includes 32 microlenses with a 500 μm pitch. Each lens in the first microlens array 406a couples the output of the splitter 404 to a corresponding TSOA in the array of TSOAs 408. In some embodiments, the seed microlens 402 and the lens array in the first microlens array 406a compensate for a height difference between a first height of the submount of the modular modulator 306 and a second height of the submount of the modular amplifier 408.

[0092] The array of TSOAs 408 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 TSOAs 408 includes 16 TSOAs. In some embodiments, the splitter 404 outputs 32 optical signals, and the array of TSOAs 408 includes 32 TSOAs. In some embodiments, the array of TSOAs 408 includes 16 aperture bars or individual multiple bars where the array includes 16 TSOAs. As described below, the array of TSOAs includes side real estate for double-sided cooling and flatness. In some embodiments, the TSOAs have a 500 μm pitch. It should be understood that in other embodiments, the array may be other types of SOAs. The array of TSOAs 408 is optically coupled to the splitter 404 by a first microlens array 406a and to the modular SiPho transceiver chip 302 by a second microlens array 406b.

[0093] The second microlens array 406b is used to optically couple the outputs of the array of TSOAs 408 to the modular SiPho transceiver chip 302. The second microlens array 406b includes a microlens for each signal output by the array of TSOAs 408. Essentially, the second microlens array 406b includes a microlens for each TSOA in the array of TSOAs 408. In some embodiments, the second microlens array 406b includes 16 microlenses with a 500 μm pitch. In some embodiments, the second microlens array 406b includes 32 microlenses with a 500 μm pitch. Each lens in the second microlens array 406b couples the output of a TSOA to a corresponding input of the modular SiPho transceiver chip 302.

[0094] In some embodiments, the first microlens array 406a, the array of TSOAs 408, 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 a p-down semiconductor structure to the left of these components 406a, 408, and 406b.

[0095] The modular components 306, 402, 404, 406a, 408, 406b, and 302 are horizontally integrated, meaning that each of the semiconductor chips forming each modular component is stacked on top of one another as shown. This requires only horizontal alignment of the different components to ensure that light can be transmitted from one modular component to the other as needed for optical coupling. In some embodiments, the optical ports of each 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] 5 is a high-level block diagram illustrating 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, a plurality of seed microlenses 502a-502d, a plurality of splitters 504a-504d, a first plurality of microlens arrays 506a-506d, a plurality of TSOA chips 508a-508d, a second plurality of microlens arrays 510a-510d, and a modular SiPho transceiver chip 302.

[0097] The LIDAR sensor system 500 of FIG. 5 is further modularized by dividing the splitter 404 into multiple splitter chips 504a-504b, dividing the first microlens array 406a into multiple microlens arrays 506a-506d, dividing the TSOA chip 408 into multiple TSOA chips 508a-508d, and dividing the second microlens array 406b into multiple microlens arrays 510a-510d. Such modular architecture variations increase yield and reliability by having components that are more easily manufactured. Such architectures require 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, the modular modulator 306, and the 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-502d. Each of the plurality of microlenses 502a-502d is optically coupled to a corresponding splitter 504a-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, each of the plurality of splitters 504a-504d is a splitter chip. For example, if an architecture similar to that of Figure 4 is desired and the modular splitter 404 is a 1-to-16 splitter, each of the plurality of splitters 504a-504d would be a 1-to-4 splitter chip, and thus the four splitter chips 504a-504d of Figure 5 can provide the same functionality as the single modular splitter 404 of Figure 4. Each of the plurality of splitters 504a-504d couples a respective microlens 502a-502d to a respective microlens array 506a-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 to illustrate how any number of splitter chips with smaller splitting ratios can be used in a modular manner in place of a single splitter chip with a larger splitting ratio.

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

[0102] As shown in FIG. 5, each of the multiple TSOA chips 508a-508d amplifies the optical signal received from a corresponding microlens array 506a-506d. In some embodiments, the design includes four TSOA chips 508a-508d. Again, continuing to compare the modular design of FIG. 4 with the modular design of FIG. 5, the single array of TSOA 408 is replaced with multiple TSOA chips 508a-508d. In contrast to the single array of TSOA 408, each of the TSOA chips 508a-508d includes four TSOAs. The multiple TSOA chips 508a-508d may have, in some embodiments, 16 aperture bars or individual multiple bars, double-sided cooling, side spacing for flatness, and a 500 μm pitch. It should be understood that in other embodiments, the TSOA chips 508a-508d may be other types of SOAs.

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

[0104] FIG. 6 illustrates a high-level block diagram showing an example floor plan of modular components for an autonomous vehicle LIDAR sensor system 600, according to some embodiments. FIG. 6 illustrates one floor plan implementation 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, multiple semiconductor optical amplifiers 602a-602d, and multiple lenses 604a-604d. As shown, the seed laser assembly 314 inputs an optical beam to modular components on an integrated circuit 606, including 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 optical amplifier 602d of the multiple semiconductor optical amplifiers 602a-602d via lens 604d. The semiconductor optical amplifiers 602a-602d are coupled to each other to transmit and receive optical signals. Additionally, each of the multiple semiconductor optical amplifiers 602a-602d is coupled by a respective lens 604a-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 respective 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.

[0105] FIG. 7 is a cross-sectional view illustrating an example integrated chip packaging 700 for a modular LIDAR sensor system for an autonomous vehicle, according to some embodiments. In FIG. 7 , the integrated chip packaging 700 for the LIDAR sensor system defines an arrangement of optical components that provides a path for optical signals or beams to travel in and out of the integrated chip packaging 700 and dissipates heat generated by the optical components to improve performance. The integrated chip packaging 700 may include a lid 704 covering a 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 to hermetically seal the optical components. For example, the U-shaped block 706 may be formed of copper. The integrated chip packaging 700 may include a cooling plate 702 coupled to a side of the integrated chip packaging 700. In some embodiments, the cooling plate 702 may be coupled to the lid 704 such that the cooling plate 702 is on top of the lid 704. In other embodiments, the cooling plate 702 may be coupled to the U-shaped block 706 such that it is underneath 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 any of copper, aluminum, and silicon.

[0106] The integrated chip packaging 700 may include a silicon photonics transceiver chip 712 separated from the MOB 708. The transceiver chip 712 is coupled to the MOB 708 via a micro-optics assembly 710 and configured to receive a beam output by the MOB 708. For example, the micro-optics 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 include an assembly of a semiconductor optical amplifier (SOA) array chip 714. The SOA array chip 714 may be implemented as a III-V semiconductor module coupled to the transceiver chip 412 via hybrid integration on the top surface of the transceiver chip 712. This hybrid integration is useful for eliminating the need for a micro-optics assembly to couple the SOA array chip 714 to 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 the bottom U-shaped block 706 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, and organic polymer. The optical window 720 allows the beam to travel in and out of the surface-emitting transceiver chip 712. After amplifying the beam using the SOA array chip 714 assembly on the top surface, the transceiver chip 712 is configured to emit the beam vertically from the bottom surface through the optical window 720. For example, the beam is emitted from the integrated chip packaging 700 perpendicular to the bottom 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 configure compared to edge emission from the transceiver chip 712. If the beam is emitted from the edge of the transceiver chip 712, the optical window 720 needs to be precisely aligned so that the optical window 720 is level with the narrow edge of the transceiver chip 712. In this way, the surface-emission feature of the transceiver chip 712 provides easy assembly and manufacturability of the integrated chip packaging 700. The transceiver chip 712 may be configured to extend laterally from the optical window 720 by a threshold offset to sufficiently overlap the optical window 720 within the integrated chip packaging 700. The end of the transceiver chip 712 that extends laterally from the optical window 720 may be bonded to a support structure 724 for mechanical strength. In one example, the dimensions of the optical window may be millimeters long by millimeters wide. The distance between the bottom surface of the transceiver chip 712 and the optical window 720 may be approximately X microns.

[0108] The 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 comprise a photodiode, generate a photocurrent based on the reflected beam collected through the optical window 720, and send 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 wire bonds 728. In some embodiments, the integrated chip packaging 700 may include a TIA 722 on a surface of a chip carrier outside the transceiver chip 712 and coupled to the transceiver chip 712. In other embodiments, integrated chip packaging 700 excludes TIA 722 from the packaged integration, for example, TIA 722 is located outside integrated chip packaging 700.

[0109] In some embodiments, the integrated chip packaging 700 may include a double-sided heat transfer assembly configuration to radiate heat generated by the enclosed components during operation and maintain the temperature of the enclosed 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 a lower surface of the transceiver chip 712 so as to be disposed 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 an exposed upper surface of the SOA array chip 714 so as to be disposed between the SOA array chip 714 and the lid 704 of the integrated chip packaging 700 for heat dissipation. For example, the heat transfer component may be a thermal interface material (e.g., aluminum nitride (AlN) ceramic, beryllium oxide ceramic, pyrolytic graphite sheet (PGS), etc.), a thermoelectric cooler (TEC), a liquid cooling system, or a combination thereof. In the example of FIG. 7, the first heat transfer component 718 may be a thermoelectric cooler or an 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 emitted from the bottom surface of the transceiver chip 712 through the optical window 720. The combination of the small optical window 720 and the low height of the 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 foregoing detailed description of the present disclosure has been presented for purposes of illustration and description. It is not intended to be complete or to limit the disclosure to the precise form disclosed. Many modifications and variations are possible in light of the above teachings. The described embodiments were selected to best explain the principles of the present disclosure and its practical application, and thus to enable those skilled in the art to best utilize the present disclosure through various modifications suited to the particular uses contemplated in the various embodiments. The scope of the present disclosure is intended to be defined by the claims appended hereto.

[0111] Although some embodiments of the present disclosure and its advantages have been described in detail, it should be understood that various modifications, substitutions, and alterations are possible without departing from the spirit and scope of the present disclosure, as defined by the appended claims. For example, those skilled in the art will readily understand that many of the features, functions, processes, and materials described herein can be modified within the scope of the present disclosure. Furthermore, the scope of the present disclosure is not intended to be limited to the particular implementations of the processes, machines, manufacture, compositions of matter, means, methods, and steps described herein. As those skilled in the art will readily understand from the description of the present disclosure, currently existing or future developed processes, machines, manufacture, compositions of matter, means, methods, and steps can perform substantially the same function or achieve substantially the same result as the implementations described herein in accordance with the present disclosure. Therefore, it is intended that the appended claims include within their scope such processes, machines, manufacture, compositions of matter, means, methods, or steps.

Claims

1. 1. A light detection and ranging (LIDAR) sensor system for a vehicle, comprising: 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 to generate an amplified beam, the modular amplifier including a specialized semiconductor optical amplifier having multiple apertures; a modular transceiver chip coupled to the modular modulator and the modular amplifier, the modular transceiver chip configured to emit the beam perpendicularly from a first surface of the modular transceiver chip through an optical window and to receive the beam reflected from a target through the optical window.

2. 10. The LIDAR sensor system of claim 1, wherein the seed laser comprises a laser having a grating structure that provides optical feedback to output the beam.

3. 3. The LIDAR sensor system of claim 2, wherein the seed laser includes a lens that couples the beam to a modular modulator, the lens having a pitch in the range of 450 to 550 micrometers.

4. 10. The LIDAR sensor system of claim 1, wherein the modular modulator performs in-phase and quadrature modulation to generate the modulated beam.

5. 10. The LIDAR sensor system of claim 1, wherein the modular modulator performs frequency modulation to generate the modulated beam.

6. 10. The LIDAR sensor system of claim 1, wherein the modular modulator and the seed laser are integrated on a single chip.

7. 7. The LIDAR sensor system of 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 a height of the seed laser with a height of the modular transceiver chip for optical coupling.

8. The LIDAR sensor system of claim 1 , wherein the modular amplifier comprises a semiconductor optical amplifier.

9. 10. The LIDAR sensor system of claim 1, wherein the modular amplifier comprises a tapered semiconductor optical amplifier configured to receive the modulated beam from the modular modulator and produce the amplified beam by stimulated emission of light.

10. 10. The LIDAR sensor system of 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. 10. The LIDAR sensor system of claim 1, wherein the specific semiconductor optical amplifier includes additional material on its side for bow management.

12. 10. The LIDAR sensor system of claim 1, wherein the modular amplifier includes a first bar attached to a first portion of the modular amplifier and a second bar attached to a second portion of the modular amplifier, the second bar having a thermal expansion coefficient that matches a thermal expansion coefficient of the first bar, and the first bar and the second bar configured to reduce a junction temperature of the modular amplifier.

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

14. 14. The LIDAR sensor system of claim 13, wherein 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.

15. 10. The LIDAR sensor system of claim 1, further comprising a splitter coupling the modular modulator to the modular amplifier, the splitter comprising a 1 to 16 splitter having a pitch in a range of 450 to 550 micrometers.

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