Optical components for scanning lidar

Abstract

A LiDAR transmitter photonic integrated circuit (PIC) for scanning an environment over a field of view (FOV) having an azimuthal range and a polar range, the LiDAR transmitter PIC comprising: a light source for providing light from at least one laser; an optical switch having an input and a plurality of outputs, the optical switch configured to selectively direct light received at the input to one of the plurality of outputs; and a light emitting component having a plurality of inputs and a plurality of emitters, the light emitting component configured to selectively emit beams over a plurality of emission angles having different respective polar components within the polar range of the FOV, wherein the light source is coupled to the input of the optical switch, and each of the plurality of outputs of the optical switch is coupled to a respective one of the plurality of inputs of the light emitting component.

Description

[0001] This application claims priority to US 62 / 802164, filed February 6, 2019; US 62 / 828376, filed April 2, 2019; US 62 / 820761, filed March 19, 2019; US 62 / 824223, filed March 26, 2019; and US 62 / 838768, filed April 25, 2019, the contents and elements of which are incorporated herein by reference for all purposes. Technical Field

[0002] The present invention relates to imaging components and diffractive optical elements, and particularly, but not exclusively, to components for use in LiDAR, such as LiDAR transmitters, LiDAR receivers and LiDAR transceivers. Background Technology

[0003] When designing the imaging receiver, it may be advantageous to collect sufficient light to meet the optical link budget, ensuring that enough signal reaches the processing unit so that the image can be reproduced.

[0004] In a LiDAR system, 3D information about the environment of interest is collected by emitting a laser and measuring the wavelength and / or return time of the reflected light received by a receiving element. Therefore, the receiving element in such a system can be configured to collect sufficient light to allow for reliable measurement of the reflected light.

[0005] The collected light is processed by a receiver, which measures the received light to infer 3D information about the environment. The emitted light is emitted by a transmitter. Optical components (such as lenses and diffractive optical elements (DOEs)) may also be used to provide a receiving area large enough to collect sufficient received light to infer 3D information about the environment and to collect light incident from different directions. A LiDAR transceiver as discussed in this specification includes a transmitter and a receiver and may include optical components such as one or more lenses and / or one or more DOEs. LiDAR can be used for 3D imaging sensors or facial recognition, etc.

[0006] “Simple and universal method in designs of high-efficiency diffractive optical elements for spectrum separation and beam concentration”, Wen-Qi Xu, Chin.Phys.B Vol.26, No.7 (2017)074202 provides examples of designs for diffractive optical elements used in solar cell systems to collect light for power acquisition.

[0007] The present invention has been designed based on the above considerations. Summary of the Invention

[0008] LiDAR systems use light to scan the field of view in an environment to create a 3D map of the environment. Light is emitted by a LiDAR transmitter, interacts with objects in the environment (e.g., reflects off them), and is then received by a LiDAR receiver. Distances to objects in the environment can be calculated from the received light using techniques such as FMCW or time-of-flight.

[0009] Some applications of the components explained in this article are in LiDAR for 3D imaging, such as in navigation, such as in vehicles (such as cars or drones) (which can be autonomous), medical imaging, consumer product imaging, augmented reality, virtual reality, front-facing cameras, feature recognition (such as facial recognition, room scanning, clothing size recognition, etc.), and industrial imaging (e.g., for use in robots).

[0010] The emission direction of the light is scanned across the field of view to sample each point in the field of view and collect distance measurements at each direction / angle in the field of view. Each point is in the emission direction of the light from the transceiver. In this specification, this direction may be referred to as an angle or emission angle. In this specification, an angle specifies a direction along which the beam travels. This angle can be measured from a direction perpendicular to a surface from which the beam travels / towards the surface. For example, when the beam leaves the transmitter component, the angle can be measured from a direction perpendicular to the front surface of the transmitter component. When the beam reaches the receiver component, the angle of the beam can be measured from a direction perpendicular to the front surface of the receiver component. Each point to be detected in the environment to be scanned is a certain distance from the LiDAR transceiver in one direction (to be calculated using LiDAR). In other words, each point to be detected is a distance away from the transceiver in one direction, which can be defined by the angle formed by that direction relative to the direction perpendicular to the transmitting / receiving surface of the transceiver.

[0011] This angle can have an azimuth component and a polar component. The field of view can consist of an azimuth range and a polar range. The azimuth and polar ranges form a field of view that can be conical or pyramidal in shape, with the apex at or near the transmitting surface of the transceiver. Depending on the orientation of the LiDAR transceiver, the azimuth and polar ranges can correspond to the horizontal and vertical directions, respectively, and vice versa. If the LiDAR transceiver is used in a bird's-eye view configuration (e.g., looking down at the ground from an aerial position), the azimuth and polar ranges can correspond to the longitudinal (front-to-back) and lateral (left-to-right) directions, and vice versa. The resolution of the LiDAR system can be measured by the angular spacing between the directions sampled in each of the azimuth and polar ranges.

[0012] Several scanning methods exist, including physically moving (e.g., rotating) the emitting component or mirror to guide the light and thus sample each direction in the field of view.

[0013] Another way to scan in a LiDAR system is by sequentially emitting light across the field of view using an optical phased array (OPA). An OPA receiver (Rx) for 3D imaging can be used to detect light returning from the environment. The OPA emitter (Tx) and receiver are stationary, meaning that unlike other 3D emitters and receivers that are physically rotated in the direction of the point to be sampled, the components of the OPA Rx and Tx, as well as the Rx / Tx, do not move. OPA systems can be configured to scan a wide range of incident angles and can scan faster and more reliably than components that require movement.

[0014] In this specification, an OPA receiver refers to an optical receiver comprising an input waveguide array, a path-matching arm waveguide array, and one or more output waveguides. The path-matching arm waveguide array is configured such that the phase delay of the light within each arm waveguide can be controlled. Each output waveguide is coupled to a photodetector, such as a coherent receiver or a single-photon avalanche diode (SPAD). Such a receiver can use OPA elements, such as arm waveguides, to guide light received from a range of angles to the receiver. The incident angle of the reflected light is known to the system controller because it corresponds to the emission angle set by the system controller in the transmitter OPA. One or more receiver OPA phase shifters can be configured to correspond to one or more transmitter OPA phase shifters, such that the received light is guided to the receiver in a manner similar to the reverse operation of the transmitter.

[0015] The OPA (Optical Image Processing Unit) can be formed by multiple inputs, a Gaussian beam splitter, a path-matched array of waveguide arms, and an emitter. The path-matched waveguide array is configured such that the phase delay of the light within each waveguide arm can be controlled. Light is supplied to the inputs and emitted into the environment by the emitter.

[0016] Another way to scan in a LiDAR system is by emitting light of multiple different wavelengths through elements (e.g., DOEs and / or one or more grating emitters) that guide light according to its wavelength. By "sweeping" through multiple wavelengths, the amount of steering influenced by the elements changes, and thus the light is emitted within an angular range in the field of view. The beam then interacts with the environment to be imaged and is subsequently collected by the imaging component. The resolution of this scanning method is determined by the angular spacing between the directions of the sequential wavelengths among the multiple wavelengths. This can be determined by the number of different wavelengths used if each different wavelength is used for one emission angle. The different wavelengths used can be a series with a constant wavelength change between consecutive beams. Different wavelengths can be emitted in any order. The diffraction angle (steer angle) is a function of the wavelength and the design of one or more elements. One or more elements can be designed according to the resolution and field-of-view requirements of the LiDAR system application.

[0017] Furthermore, the system can utilize both OPA and wavelength scanning methods; one for scanning the polar angle range and the other for scanning the azimuth range of the field of view. In the example described below, one or more 1D OPAs are used to scan the polar angle range of the field of view, and wavelength scanning is used to scan the azimuth range of the field of view. However, it should be understood that in other embodiments, the system can be rotated, for example, such that (one or more) OPAs are used to scan the azimuth range of the field of view, and wavelength scanning can be used to scan the polar angle range of the field of view.

[0018] It may be desirable to accommodate multiple beams in the system to enable faster scanning of the field of view by processing multiple beams simultaneously. Multiple beams of different wavelengths can be transmitted simultaneously and / or multiple beams can be emitted from the OPA transmitter.

[0019] There is a problem when using an OPA receiver because the receiving area might be approximately 0.5mm × 0.5mm, which may be too small as it will not collect enough light to shut down the optical link budget. In particular, if there is a maximum amount of light that can be emitted (e.g., due to safety regulations), collecting a high proportion of the emitted light may be important. To increase the collecting area (e.g., to approximately 10 × 10mm for a 200m scanning range), a collecting lens (e.g., 10mm in diameter) can be provided on top of one or more OPA receivers. However, this has the following drawbacks: Figure 1 The various significant problems shown.

[0020] For example, such as Figure 1As shown, unless the transmitting and receiving beams are pointed directly forward, the received image (e.g., a spot of light, which may have been expanded to fill the collecting lens) may miss the receiver OPA aperture. Additionally, to avoid parallax issues, ideally, the receiver aperture should be coaxial with the transmitter, which would require using the transmitter as a receiver in reverse. However, using the transmitter as a receiver in reverse generates large losses in the PIC and is therefore undesirable. The lens size and magnification required to achieve the desired collection efficiency are also much larger than the waveguide used to capture light into the PIC, resulting in a long working distance (lens-to-PIC distance) and therefore the implementation may be thicker than practical.

[0021] Figure 3A and 3B This demonstrates how this type of optics can be designed for use in PIC receivers. Figure 3B A solution for a PIC receiver is provided, which includes an optical collection gain of ~2.8 × 10⁻⁶. 6 ((10mm / 6μm) 2 The OPA will be a 50mm thick optical element (focal length + lens thickness + DOE thickness + free space), which may be impractical for most 3D imaging applications, where compactness is likely to be advantageous. Figure 3A The system is also thicker than it actually is.

[0022] In a first aspect, some embodiments of the present invention provide an imaging component for receiving light, the imaging component including a photonic integrated circuit (PIC) receiver, a plate, a wedge, and a lens, the wedge having a front surface and an opposing rear surface, the imaging component being arranged to define a received optical path through the front surface of the wedge, the received optical path continuing through the wedge and through the plate to the PIC receiver, and the lens being configured to focus the light of the received optical path onto the PIC receiver.

[0023] By utilizing the geometry of wedges and plates, the optical path through the imaging element can be collapsed, allowing the imaging element to be manufactured thinner. Using a wedge and plate arrangement, light can be guided to a waveguide-based receiver (e.g., a coherent receiver in a system such as FMCW) while controlling the phase front of the collected light to achieve high coupling efficiency in the waveguide. In systems purely based on detecting the power of reflected light, it is not necessary to maintain the phase of the reflected light through receiving optics; however, when the reflected light is to be coupled into a PIC waveguide, it may be necessary to control the phase front of the collected light to achieve high coupling efficiency in the waveguide. Advantageously, the wedge and plate arrangement is suitable for either application.

[0024] The imaging component can be a LiDAR component used to receive light.

[0025] The wedge may have a thick end and a relatively thin end, and a plate may extend from the thick end of the wedge, wherein the wedge has a length from the thick end to the thin end, and the plate has a length from the end of the wedge near the thick end to the end away from the wedge. Received light may be reflected from the rear surface of the wedge via total internal reflection or due to the use of a highly reflective coating, and guided toward the plate.

[0026] In this specification, the front surface is the surface of the component closest to the imaging environment. The rear surface is opposite the front surface, such that it is located on the side of the component opposite to the front surface (i.e., the rear surface is furthest from the imaging environment). The thickness is measured in a direction perpendicular to the plane of the front surface, from the front surface to the rear surface. The width is measured in a direction perpendicular to the thickness and perpendicular to the direction in which the thickness of the wedge changes. The length is measured in the direction in which the thickness of the wedge changes.

[0027] In some embodiments, the wedge and plate integral terrain become a single component.

[0028] The length of the wedge can be between 50% and 150% of the length of the plate.

[0029] The combined length is the length of the plate plus the length of the wedge, and the combined length can be between 20mm and 40mm.

[0030] The PIC receiver can be located at the end of the board away from the wedge.

[0031] The PIC receiver can be located behind the rear surface of the board, and the end surface of the board away from the wedge can form an angle of less than 90 degrees with the rear surface of the board, such that the received optical path is directed toward the PIC receiver as it exits the rear surface of the board. The embodiments described herein can be used in LiDAR systems, such as in frequency modulated continuous wave (FMCW) systems or time-of-flight (ToF) systems. In the case of using ToF, the PIC receiver(s) may include one or more single-photon avalanche diodes (SPADs), and in the case of using FMCW, the PIC receiver(s) may include one or more coherent receivers.

[0032] The thickness of the wedge between the front and rear surfaces at the thick end of the wedge can be between 0.5 mm and 2 mm.

[0033] The rear surface of the wedge can be coated with a high-reflectivity coating. This means that the received light does not depend on total internal reflection to remain at the rear surface of the wedge, and therefore the tilt angle between the rear and front surfaces of the wedge can be smaller. The high-reflectivity coating can be metallic or a multilayer coating.

[0034] The front surface of the wedge can be coated with an anti-reflective coating. This improves the coupling of received light into the wedge.

[0035] The plate and / or wedge may be formed of a material with a refractive index of 2 or greater, or in some embodiments, of a material with a refractive index of 3 or greater.

[0036] The rear surface of the wedge can be tilted between 8 and 9 degrees from the front surface of the wedge, and in some embodiments, 8.4 degrees. This is a suitable angle for use with high refractive index materials (e.g., silicon using a highly reflective coating).

[0037] The receiving optical path can extend through at least 90% of the front surface of the wedge. Providing a receiving optical path from most of the front surface of the wedge to the PIC receiver allows for the collection of sufficient light. The remaining portion of the front surface of the wedge can be used, for example, to provide the transmitting optical path.

[0038] The receiving optical length (through which the incident beam will travel in the wedge and plate) can be defined between each point on the front surface of the wedge and the PIC receiver, and wherein the imaging components are configured such that the receiving optical lengths are equal. Optical lengths with a phase difference less than the depth of focal length of the lenses used in the system are considered equal.

[0039] A PIC receiver may include one or more receiver optical phased arrays (OPAs).

[0040] The board can cover one or more receiver OPAs on the photonic integrated circuit.

[0041] The wedge and / or plate can be formed of silicon or germanium.

[0042] The imaging component has a lens configured to focus light onto the PIC receiver. The lens may be located in front of the front surface of the wedge. The lens may be disposed between the front surface of the wedge and the diffractive optical element, or the diffractive optical element may be located between the front surface of the wedge and the lens.

[0043] Additionally or alternatively, the lens may be located on the rear surface of the plate at the end of the plate away from the wedge, and may be formed of one or more microlenses. The lens, or one of the lenses, may be positioned between the plate and the PIC receiver. The lens may be integrated into the wedge and / or the plate and / or diffractive optical elements.

[0044] One or more lenses may be circular, elliptical, or cylindrical, or the lenses may be formed from a microlens array. The microlens array may be integrated into the bottom surface of the board and may be formed by etching the bottom surface of the board. One or more additional lenses having any of the above properties may also be provided. The PIC receiver may have one or more input waveguides, and each microlens may be configured to focus light onto the corresponding input waveguide.

[0045] The imaging component may have a diffractive optical element on the front surface of the wedge, such that the received optical path extends through the diffractive optical element, through the front surface of the wedge, through the wedge and the plate to reach the PIC receiver.

[0046] Some embodiments of the present invention provide an imaging component for receiving light, the imaging component comprising a photonic integrated circuit (PIC) receiver, a plate, and a wedge having a front surface and an opposing rear surface, the imaging component being arranged to define a received optical path through the front surface of the wedge, the received optical path continuing through the wedge and through the plate to the PIC receiver. Any of the features described above in the first aspect may be combined with these embodiments.

[0047] The wedge arrangement in some embodiments of the present invention means that when in conjunction with Figure 1 , Figure 3A and Figure 3B Compared to the examples in the previous example, the thickness of the optics can be significantly reduced. The provided wedges, plates, any lenses, and / or diffractive optical elements are used to focus, concentrate, and deflect the received light, while being positioned forward to provide good coupling to the PIC waveguide of the receiver.

[0048] The receiver and transmitter can be spatially separated. In existing systems, it may be impossible to position the receiver and transmitter PICs close enough together to avoid parallax effects. By implementing a wedge and plate arrangement, the receiving and transmitting optical circuitry can be spatially separated while avoiding parallax problems. The receiver and transmitter can be housed on a single die or on separate dies. Furthermore, this arrangement allows for the coupling of received light into the receiver PIC waveguide while maintaining the phase of the light. This can be advantageous for applications such as FMCW and PMCW LiDAR systems.

[0049] Use wedges and plates (examples are shown in...) Figure 6A and 6B (As shown in the diagram), the received light is guided away from the path of the emitted light, while still maintaining the coaxial arrangement of the received and emitted light at the surface in which the light is emitted to / received from the scanned environment (a circular example of a coaxial arrangement on the surface of a transceiver emitting / receiving light from the environment). Figure 2 (as shown in the image).

[0050] Throughout this specification, when the term coaxial is used, it refers to the arrangement of the receiving and transmitting optical paths at a surface in which light is received from and / or emitted to the environment to be scanned, and means that the transmitting optical path is located in the gap at the center of the receiving optical path at that surface.

[0051] In a second aspect, some embodiments of the present invention provide a LiDAR transceiver including an imaging component for receiving light and a PIC transmitter.

[0052] The imaging component includes:

[0053] A photonic integrated circuit (PIC) receiver, a board, a wedge, and a lens, wherein the wedge has a front surface and an opposing rear surface, and the imaging element is arranged to define a receiving optical path through the front surface of the wedge, the receiving optical path continuing through the wedge and through the board to the PIC receiver, and the lens is configured to focus the light of the receiving optical path onto the PIC receiver; and

[0054] The transceiver is arranged to define the transmitted optical path from the transmitter through the wedge and through the front surface of the wedge.

[0055] The wedge may include an emission window through which an optical path is emitted. The emission window may have optical properties configured to allow light to enter the wedge at a rear surface, pass through the wedge, and exit the wedge at a front surface.

[0056] The rear surface of the wedge can have a high-reflectivity coating, and the emission window can be located in a gap within the coating. The gap in the coating can be filled with a coating having different optical properties than the high-reflectivity coating.

[0057] High-reflectivity coatings can be metallic or multi-layered.

[0058] The launch window can be a hole formed by a wedge from the rear surface to the front surface. The hole can be a physical inlet through the wedge, or the hole can be filled with a material other than the material forming the wedge.

[0059] At the front surface of the wedge, the cross-sectional area of ​​the receiving optical path can be 20 to 200 times that of the transmitting optical path, or in some embodiments, 100 times.

[0060] The transmitter can be configured such that the transmitted optical path is located at the center of the front surface of the wedge. The received optical path can surround the transmitted optical path. In this way, parallax error can be avoided by ensuring that the transmitted and received light are coaxial.

[0061] Alternatively, the transceiver can be arranged to define a non-wedge-shaped transmission optical path from the transmitter to the environment to be imaged.

[0062] The transmitter may include a transmitter OPA.

[0063] The emitter may include one or more grating emitters configured to adjust the azimuth component of the angle of light by an amount depending on the wavelength of the light.

[0064] The transmitter OPA can be located on the photonic integrated circuit, and the wedge can cover the transmitter OPA on the photonic integrated circuit.

[0065] The transmitter can be located behind the rear surface of the wedge.

[0066] The transceiver may have a diffractive optical element on the front surface of the wedge, such that the receiving optical path extends through the diffractive optical element, through the front surface of the wedge, through the wedge and the plate to reach the PIC receiver, and the transmitting optical path extends from the transmitter, through the wedge, through the front surface of the wedge and through the diffractive optical element.

[0067] In a third aspect, some embodiments of the present invention provide a LiDAR transceiver for scanning an environment over a field of view (FOV) having an azimuth range and a polar range. The LiDAR transceiver includes a photonic integrated circuit (PIC) receiver, a PIC transmitter, and a diffractive optical element (DOE). The DOE has a front surface and a rear surface, and includes: a transmission region configured to transmit a light beam received at the rear surface of the DOE from the front surface of the DOE; and a receiving region configured to adjust the azimuth component of the light incident on the front surface of the DOE by an amount dependent on the wavelength and to transmit the light from the rear surface of the DOE, wherein the receiving region is distributed across the... On two opposite sides of the transmission area, the transceiver is configured to: transmit light from the PIC transmitter through the transmission area of ​​the DOE and emit the light into the environment, the light having an emission angle having an azimuth component within the azimuth angle range of the FOV and an polar component within the polar angle range of the FOV, the azimuth component of the emission angle depending on the wavelength of the light; receive the light from the environment; guide the light through the receiving area of ​​the DOE from the front surface to the rear surface and to the PIC receiver, wherein the receiving area of ​​the DOE is configured such that when the light is transmitted from the rear surface of the DOE, the azimuth component is independent of the wavelength of the light. In other words, the azimuth component of the light transmitted from the rear surface of the receiving area is independent of the azimuth component of the light when the light is received at the front surface of the receiving area.

[0068] The transceiver may also include a lens configured to focus light onto the PIC receiver.

[0069] The two opposite sides of the transmission region may be orthogonal to the front and rear surfaces of the DOE. The transmission region may be sandwiched between two portions of the receiving region, such that the transmission region is located between the two portions of the receiving region. The transmission region may be surrounded by the receiving region, such that the transmission region is located in the inner portion of the DOE and the receiving region is located in the outer portion of the DOE surrounding the transmission region.

[0070] In this specification, adjusting the beam means controlling or changing the angle / direction in which the beam is traveling. Adjustment can be dependent on or independent of the wavelength.

[0071] A PIC transmitter may include a grating emitter configured to adjust the azimuth component of the angle of light by an amount that depends on the wavelength of the light.

[0072] The transmission zone of the DOE can also be configured to adjust the azimuth component of the light angle depending on the wavelength of the light.

[0073] The transmission zone of the DOE can also be configured to split the light received at the rear surface of the DOE into multiple beams, and transmit each of the multiple beams from the front surface of the DOE at different corresponding azimuth angles.

[0074] The transceiver may also include one or more additional PIC receivers, and the DOE's receiving area is configured to tune each of the multiple beams to a corresponding PIC receiver.

[0075] The receiving area may include multiple sub-areas, each of which is configured to adjust a corresponding beam from a plurality of beams to its corresponding receiver.

[0076] The transmission region can be located at the center of the diffractive optical element, and the receiving region can surround the transmission region.

[0077] The lens can be located between the DOE and the PIC receiver. The lens can also be located on the front surface of the DOE.

[0078] Lenses and DOEs can be integrally formed from a single component with focusing and diffraction characteristics.

[0079] A lens may include a transmission region and a receiving region, wherein the receiving region is located on two opposite sides of the transmission region. The transmission region may be located at the center of the lens, and the receiving region may surround the transmission region. The transmission and receiving regions may have different optical properties. The transmission and receiving regions may be aligned with the transmission and receiving regions of a DOE, respectively.

[0080] The receiving area may include at least 90% of the front surface of the DOE.

[0081] The LiDAR transceiver may also include a plate and a wedge having a front surface and an opposing rear surface. The transceiver is arranged to define a received optical path through the front surface of the wedge, the received optical path continuing through the wedge and through the plate to a PIC receiver. A lens is configured to focus the light of the received optical path onto the PIC receiver. The transceiver is arranged to define a transmitted optical path from the transmitter through the wedge and through the front surface of the wedge.

[0082] The transceiver can be configured to transmit light from the PIC transmitter along the transmit optical path through the wedge and through the front surface of the wedge, and transmit light through the transmission region of the DOE's transmission area. To achieve this, the transmission region of the DOE can be aligned with the transmit optical path in the wedge.

[0083] In a fourth aspect, some embodiments of the present invention can provide a LiDAR transceiver for scanning an environment over a field of view (FOV) having an azimuth range and a polar range. The LiDAR transceiver includes a photonic integrated circuit (PIC) receiver, a PIC transmitter, a plate, a wedge, a lens, and a diffractive optical element (DOE). The wedge has a front surface and an opposing rear surface, and the DOE has a front surface and a rear surface. The DOE includes: a transmission region configured to transmit a light beam received at the rear surface of the DOE from the front surface of the DOE; and a receiving region configured to adjust the azimuth component of the light incident on the front surface of the DOE by an amount dependent on the wavelength and to transmit the light from the rear surface of the DOE. The receiving regions are distributed on two opposing sides of the transmission region, and the transceiver is configured to: travel along the wedge and through the wedge... The front surface emits light from the PIC transmitter, transmits the light through the transmission area of ​​the DOE, and emits the light into the environment. The light has an emission angle having an azimuth component within the azimuth range of the FOV and an polar component within the polar range of the FOV. The azimuth component of the emission angle depends on the wavelength of the light. The light is received from the environment, guided from the front surface to the rear surface through the receiving area of ​​the DOE, and along the receiving optical path through the wedge on the front surface. The receiving optical path continues through the wedge and through the plate to the PIC receiver. The lens is configured to focus the light of the receiving optical path onto the PIC receiver, and the receiving area of ​​the DOE is configured such that when the light is transmitted from the rear surface of the DOE, the azimuth component is independent of the wavelength of the light. In other words, the azimuth component of the light transmitted from the rear surface of the receiving area is independent of the azimuth component of the light when the light is received at the front surface of the receiving area.

[0084] The imaging component according to the first aspect may further include a diffractive optical element of the third aspect, the diffractive optical element being positioned at the front surface of the wedge such that the received optical path extends through the diffractive optical element, through the front surface of the wedge, through the wedge and the plate to reach the PIC receiver.

[0085] The LiDAR transceiver according to the second aspect may also include a diffractive optical element of the third aspect, the diffractive optical element being located at the front surface of the wedge, such that the received optical path extends through the diffractive optical element, through the front surface of the wedge, through the wedge and the plate to the PIC receiver, and the transmitted optical path extends from the transmitter, through the wedge, through the front surface of the wedge and through the diffractive optical element.

[0086] These combinations of features and aspects described above can offer additional advantages. For example, using a DOE as described in the third aspect with a transceiver as described in the second aspect can reduce parallax error in the system because the DOE's transmit path and transmission zone are positioned very close to or overlap with its receive counterpart. The wedge allows for separation of the receiver and transmitter while allowing both the transmit and receive path to pass through the front surface of the wedge, and the DOE's receive zone is distributed on two opposite sides of the transmission zone, thus the zones for receiving and transmitting light overlap. Therefore, the combination of these two features is used to further reduce parallax error.

[0087] To sample a large field of view (FOV) with fine resolution, a large number of angles need to be sampled. It can be difficult to control the emitting components at sufficiently discrete angles. For example, to cover a 90-degree FOV using an OPA with a beamwidth of 0.1 degrees at vertical emission, 810 beams could be created to cover the FOV. This number is less than 990° / 0.1° = 900 when the beamwidth increases with the steering angle θ at a rate inversely proportional to cosθ (therefore the beamwidth is approximately 0.14° at the limiting angle ±45° of the FOV). Generating 810 beams from a Gaussian emitter envelope profile, truncated at 99% power, can be achieved using 912 waveguide emitters spaced 1.1 μm apart. Gaussian OPAs are optimal for sidelobe suppression, and the 99% Gaussian truncation is a good balance between minimizing insertion loss, beam broadening, and sidelobe degradation on one side and the number of emitters on the other. This is a proven size, but requires the simultaneous control of many phase shifter elements, such as... Figure 15 As shown. The number of phase shifters implies that the system control is complex.

[0088] In another aspect, the present invention can provide a LiDAR emitter photonic integrated circuit (PIC) for scanning an environment over a field of view (FOV) having an azimuth range and a polar range. The LiDAR emitter PIC includes: a light source for providing light from at least one laser; an optical switch having an input and a plurality of outputs configured to selectively direct light received at the input to one of the plurality of outputs; and a light-emitting element having a plurality of inputs and a plurality of emitters configured to selectively emit beams at a plurality of emission angles having different corresponding polar components within the polar range of the FOV, wherein the light source is coupled to the input of the optical switch, and each of the plurality of outputs of the optical switch is coupled to a corresponding one of the plurality of inputs of the light-emitting element.

[0089] In this way, by directing light to one of the multiple inputs to the light-emitting component, an optical switch can be used for coarse steering of the light, and the light-emitting component can be used for fine-tuning the direction of the emitted light. This arrangement enables scanning the direction of the field of view (FOV) with reduced optical loss and allows simple switching elements to be cascaded together to reduce component size and decrease the complexity of adjusting light across the FOV. Multiple inputs to the light-emitting component mean that fewer steering (e.g., phase shifts) are required within the light-emitting component, thus reducing complexity.

[0090] The emitters can be evenly spaced.

[0091] The transmitter PIC may also include multiple beam splitters, each having an input and multiple outputs, and configured to separate light received at the input among the multiple outputs, wherein each output of the optical switch is coupled to a corresponding input of the beam splitter, and each output of each beam splitter is coupled to a corresponding input of the light-emitting element.

[0092] In this way, multiple beams can be emitted simultaneously, enabling faster scanning of the field of view by processing multiple beams at the same time. The beams can be spatially differentiated at the receiver. The angle of incidence can be converted from the receiver waveguide by optics in front of the receiver waveguide. Using a beam splitter with a light-emitting element having multiple inputs means that a single light-emitting element can simultaneously emit beams with different emission angles.

[0093] The light-emitting component may include at least one optical phased array (OPA), which or each optical phased array is configured to selectively emit a beam at one or more of a plurality of emission angles.

[0094] The light-emitting component may include multiple OPAs, and each of the multiple inputs of the light-emitting component includes an input to one of the multiple OPAs, and each of the multiple emitters of the light-emitting component may include an output of one of the multiple OPAs. The light-emitting component may include twelve OPAs. In this way, each of the multiple OPAs can be configured to correspond to a respective sub-range of the polar angle range, such that the OPA emitting light determines the sub-range of the polar angle from which light can be emitted from the light-emitting component. This reduces the amount of phase shift required in the OPAs, because the coarse steering of the light effectively occurs in the optical switching of the selected OPA. Each OPA then only needs to guide the light over a narrower sub-range of the polar angle component of the FOV.

[0095] The OPA, or each OPA, can have more than one input. For example, the OPA, or each OPA, can have eight inputs. In this way, each input of the OPA can correspond to a corresponding subrange of a polar angle range (where the OPA emits light), such that the input (where the light reaches the OPA) determines the subrange of polar angles from which light can be emitted from the light-emitting component. This means that less phase shift is needed in the OPA because the coarse steering of the light has already occurred in the optical switch, and the OPA only handles the fine steering.

[0096] The light-emitting component can have at least 900 emitters, for example, 912 emitters. As mentioned above, approximately 900 emitters are sufficient for a field of view (FOV) of approximately 90 degrees measured vertically and a beamwidth of 0.1 degrees. Each OPA can have an equal number of emitters. Each OPA can have seventy-eight emitters. The OPA, or each OPA, can be configured to selectively emit light with sixty-eight discrete polar angle components. The emitters can be spaced between 1 μm and 2 μm, or spaced 1.1 μm apart.

[0097] When measuring light emitted vertically from an OPA, the OPA or each OPA can be configured to emit light with a beam width between 0.5 and 2 degrees or no greater than 1.2 degrees.

[0098] The outputs of more than one of multiple beam splitters can be alternately coupled to the input of one or more OPAs, such that two adjacent inputs without an OPA are coupled to the same output of an optical switch. The number of outputs from each beam splitter can be half the number of inputs to that OPA or each OPA, and the outputs from two beam splitters can be alternately coupled to the input of one of the OPAs. In this way, simultaneously emitted beams can be separated at a greater angle, making them easier to distinguish at the receiver.

[0099] Each beam splitter can have four outputs. The four outputs of the first beam splitter and the four outputs of the second beam splitter can be coupled to one of the eight inputs of one of the OPAs in an alternating arrangement, such that two adjacent inputs of no OPA are coupled to the same beam splitter.

[0100] Two beam splitters can be formed by a combined beam splitter that includes a first input and a second input and an array of eight outputs, wherein light from the first input and light from the second input are directed to alternating outputs in the array of eight outputs, such that no two adjacent outputs receive light from the same input.

[0101] The optical switch can have 24 outputs. The optical switch may include one or more of the following:

[0102] A 1×2 Mach-Zehnder switch with one input and two outputs, and / or

[0103] A 1×3 Mach-Zehnder switch with one input and three outputs, and / or

[0104] A 1×4 Mach-Zehnder switch with one input and four outputs, and / or

[0105] An OPA switch includes an input, an arm waveguide array, and multiple outputs. The OPA switch is configured to selectively shift the phase of light in the arm waveguides, the amount of which depends on the arm waveguides in which the light travels, so as to selectively direct the light to one of the outputs.

[0106] Optical switches may include:

[0107] 23 1×2 Mach-Zehnder switches arranged in the tree, or

[0108] Arranged in the tree are 1×3 Mach-Zehnder switches and 21 1×2 Mach-Zehnder switches, or

[0109] 1×4 Mach-Zehnder switch and 3 1×6 OPAs, or

[0110] 1×24OPA switch.

[0111] The LiDAR transmitter PIC can be configured to emit multiple beams simultaneously. The LiDAR transmitter PIC can be configured to emit four beams simultaneously.

[0112] The OPA of the light-emitting component, or each OPA, may also include an array of arm waveguides and one or more phase shifters configured to shift the phase of light in the arm waveguides, the applied phase shift depending on the arm waveguide in which the light travels. The phase shift may vary linearly across the arm waveguide array. The phase shifters (one or more) may be one or more heaters. The one or more heaters may be configured to apply heat to a corresponding length of each corresponding arm waveguide in the array, the corresponding length varying across the array of arm waveguides. The corresponding length may vary linearly and / or continuously across the arm waveguide array. Each of the one or more heaters may have a triangular shape. The triangular shape includes any shape that increases across the array length (in the direction of the arm waveguide). For example, substantially triangular shapes, such as rounded triangles, where one or more corners of the triangle are rounded, or triangular shapes where one or more sides are curved in a concave or convex manner.

[0113] The light source may include multiple lasers, each configured to produce light of a corresponding different wavelength within a wavelength range, and the emitter may be a grating emitter configured to tune light having wavelengths within the wavelength range to a corresponding azimuth component. As an addition to or alternative to the grating emitter, a diffractive optical element (DOE) may be provided separately to the PIC to tune the light based on wavelength. Alternatively, the light source may be an input waveguide suitable for connection to one or more external lasers.

[0114] The light source can also provide a local oscillator (LO) output, which can be connected to the receiver PIC to provide an LO source.

[0115] The azimuth range can be smaller than the polar range. The transmitter can be oriented to change the vertical direction of the polar component scan and the horizontal direction of the azimuth component scan. The transmitter orientation can be selected according to the application.

[0116] The emitter PIC can be configured to simultaneously generate multiple corresponding different wavelengths of light within a wavelength range, and the grating emitter can be configured to separate the light. As described above, wavelength-based light steering and / or separation can be provided by the grating emitter and / or a separate DOE.

[0117] The light source may also include multiple modulators, each configured to modulate light from a corresponding laser among a plurality of lasers. The lasers, or each laser, may be tunable over a corresponding wavelength subrange within a wavelength range. The lasers, or each laser, may be thermally tunable. The lasers, or each laser, may be tunable at intervals between 2 nm and 5 nm, or at 3 nm intervals. Each laser may include a ring resonator. Alternatively, the light source may be an input waveguide suitable for connection to one or more external lasers and the aforementioned modulators.

[0118] The diffraction element at the receiver can guide the received light based on wavelength in a manner opposite to that of the transmitter grating emitter / DOE. Therefore, coding in the emitted light allows the receiver to determine the azimuth of the received light source. Modulation in the light can be provided to allow distance calculation at the receiver. This coding can also allow the use of coded or tracking signals to distinguish between simultaneous beams of different wavelengths. The tracking signal is an out-of-band modulation that can be added to the beam to identify the origin of the beam without affecting the emitted application signal. This can indicate the origin in azimuth or polar coordinates, or both. For example, in a dense wavelength division multiplexing (DWDM) system, low-frequency (kHz) tones of different frequencies are added to each wavelength, allowing the wavelength to be identified by monitoring the frequency of that tone.

[0119] The light source may include thirty-two lasers, and the thirty-two lasers may be provided by four eight-channel dies.

[0120] The transmitter PIC may further include: a second beam splitter having an input and multiple outputs, and configured to separate light received at the input among the multiple outputs; and one or more additional light-emitting elements, each or every additional light-emitting element having multiple inputs and multiple emitters, each additional light-emitting element including at least one OPA, each or every OPA being configured to selectively emit a beam at multiple emission angles having different corresponding polar components within the polar angle range of the FOV; and wherein the light-emitting elements and the additional light-emitting elements are each configured to selectively emit a beam at different corresponding ranges of azimuth components, wherein the input to the second beam splitter is coupled to the light source, and a first output of the outputs of the second beam splitter is coupled to the input of the light-emitting element, and one or more other outputs of the second beam splitter are coupled to the input of a corresponding additional light-emitting element. In this way, the azimuth range can be separated among the light-emitting elements, such that each light-emitting element only needs to cover a narrower range of azimuth angles. When the azimuth component is adjusted depending on the different wavelengths of light, this reduces the range of required wavelengths, thereby simplifying the manufacture of these components. Each light-emitting component can operate on a sub-range of the azimuth component, which can be adjusted by optics, so that the light-emitting components together cover the entire azimuth range of the field of view (FOV).

[0121] The LiDAR emitting component may also include an air-to-air grating configured to create multiple beams for each emitted wavelength, each beam having a different azimuth component.

[0122] The azimuth sub-range can be 15 degrees wide. Two additional light-emitting elements can be present, resulting in three light-emitting elements, each configured to selectively emit a beam over a corresponding range of the three sub-azimuth ranges. Each sub-azimuth range can have a width of 15 degrees, and each sub-azimuth range can be separated by 15 degrees, such that together they cover a 45-degree azimuth range.

[0123] LiDAR emitting components may also include angular magnification optics to increase the azimuth component of the emission angle. The magnified azimuth range can be as wide as 45 degrees. In this way, the grating emitter and / or DOE can emit a beam over a smaller azimuth range, which is then magnified by the optics to cover the azimuth range of the field of view (FOV). This reduces the steering angle at which the grating emitter and / or DOE need to operate, thus simplifying the fabrication of these components, especially when the azimuth component is adjusted depending on the different wavelengths of light.

[0124] Some embodiments of the present invention may provide a LiDAR emitting component comprising a LiDAR emitter PIC and a first optics configured to convert light emitted from each OPA from a first polar angle range emitted by the OPA to a second polar angle range, the second polar angle range being smaller than the polar angle range of the field of view (FOV), and a second optics configured to adjust the light from each OPA to a corresponding polar steering angle. The steering angle may be ±yn, where n is an integer and y is the size of the second polar angle range. The first polar angle range may be ±45 degrees, and / or the second polar angle range may be ±3.75 degrees. The polar angle range of the FOV may be the same as the first polar angle range and / or may be ±45 degrees.

[0125] In another aspect, some embodiments of the present invention may provide a LiDAR receiver PIC comprising: an optical steering component having a plurality of input waveguides and a plurality of outputs; a local oscillator (LO) source providing one or more LO signals; an optical switch having an input and a plurality of outputs configured to selectively guide light received at an input to one of the plurality of outputs; and a plurality of coherent receivers, each having a signal input and an LO input and at least one photodetector, wherein the LO source is coupled to the input of the optical switch, and each of the outputs of the optical switch is coupled to a corresponding one of the LO inputs, and wherein each of the outputs of the optical steering component is coupled to a corresponding one of the signal inputs.

[0126] Similar to the transmitter described above, this arrangement of the receivers allows the optical switch to perform coarse steering by selecting the coherent receiver to use. This means the optical steering component can provide less optical steering, as the incident light can be guided to the appropriate output among multiple outputs. This arrangement allows for scanning the direction of the field of view (FOV) with reduced optical loss and allows simple switching elements to be cascaded together to reduce component size and the complexity of guiding light across the FOV. Multiple outputs to the optical steering component mean less steering (e.g., phase shift) is required within the optical steering component, thus reducing complexity.

[0127] The input waveguides can be equally spaced. The optical steering component can include an optical phased array (OPA).

[0128] An optical steering component may include multiple Optical Points (OPAs), and each of the multiple input waveguides of the optical steering component may include an input to one of the multiple OPAs, and each of the multiple outputs of the optical steering component may include an output of one of the multiple OPAs. An optical steering component may include twelve OPAs. In this way, each of the multiple OPAs can be configured to correspond to a respective sub-range of a polar angle range, such that the OPA receiving the light determines the sub-range of the polar angle from which the light arriving at the optical steering component may originate. This reduces the amount of phase shift required in the OPAs, because coarse steering of the light effectively occurs in the optical switching of the selected OPAs. Each OPA then only needs to guide the light received from the narrower sub-range of the polar angle component of the field of view (FOV).

[0129] Each OPA can have an equal number of inputs. The OPA, or each OPA, can have seventy-eight input waveguides. The OPA, or each OPA, can have more than one output. In this way, each output of the OPA can correspond to a corresponding subrange of polar angles on which the OPA receives light, such that the output to which the light is guided by the OPA determines the subrange of polar angles from which the light may originate. This means that less phase shift is needed in the OPA because coarse steering of the light effectively occurs in the optical switch, and the OPA only handles fine steering. The OPA, or each OPA, can have eight outputs. The OPA, or each OPA, can be configured to receive light from sixty-eight discrete angles in a first plane. The input waveguides can be spaced 1 to 2 μm apart, or the input waveguides can be spaced 1.1 μm apart.

[0130] The LiDAR receiver PIC may also include multiple beam splitters, each having an input and multiple outputs, and configured to separate the light received at the input among the multiple outputs, wherein each output of an optical switch is coupled to a corresponding input of one of the beam splitters, and each output of each beam splitter is coupled to a corresponding LO input of one of the coherent receivers.

[0131] In this way, multiple beams can be received simultaneously, enabling faster field-of-view scanning by processing multiple beams concurrently. Beams can be spatially distinguished. The angle of incidence can be converted from the angle of incidence by optics in front of the receiver waveguide. Using a beam splitter with multiple output optical steering components means that beams with different angles of incidence can be received and processed simultaneously using a single optical steering component.

[0132] Each beam splitter can have four outputs. Two beam splitters can form a combined beam splitter, which includes a first input, a second input, and an array of eight outputs. Light from the first input and light from the second input are directed to alternating outputs in the array of eight outputs, such that no two adjacent outputs receive light from the same input. In this way, simultaneously received beams can be separated at a greater angle, making them easier to distinguish.

[0133] Each coherent receiver may include a pair of multimode interferometers (MMIs), each MMI having one of the LO inputs and one of the signal inputs of the coherent receiver, and the outputs of the two MMIs in the pair to one or more common photodetectors, wherein the two LO inputs in the pair are each coupled to different outputs of an optical switch.

[0134] Optical switches may include one or more of the following:

[0135] A 1×2 Mach-Zehnder switch with one input and two outputs, and / or

[0136] A 1×3 Mach-Zehnder switch with one input and three outputs, and / or

[0137] A 1×4 Mach-Zehnder switch with one input and four outputs, and / or

[0138] An OPA switch, comprising an input, an arm waveguide array, and multiple outputs, is configured to selectively shift the phase of light in the arm waveguides, the amount of which depends on the arm waveguide in which the light travels, in order to selectively direct the light to one of the outputs.

[0139] The optical switch can have twenty-four outputs, and the optical switch can include:

[0140] 23 1×2 Mach-Zehnder switches arranged in the tree, or

[0141] Arranged in the tree are 1×3 Mach-Zehnder switches and 21 1×2 Mach-Zehnder switches, or

[0142] 1×4 Mach-Zehnder switch and 3 1×6 OPAs, or

[0143] A 1×24 OPA switch comprising an input, an arm waveguide array, and 24 outputs, the OPA switch being configured to selectively shift the phase of light in the arm waveguides, the amount of phase shift being dependent on the arm waveguide in which the light travels, so as to selectively direct the light to one of the outputs.

[0144] The optical steering component, or each OPA, may further include an array of arm waveguides and one or more phase shifters configured to shift the phase of light in the arm waveguides, the applied phase shift depending on the arm waveguide in which the light travels. The phase shift may vary linearly across the arm waveguide array. One or more phase shifters may be one or more heaters. The one or more heaters may be configured to apply heat to a corresponding length of each respective arm waveguide in the array, the corresponding length varying across the array of arm waveguides. The corresponding length may vary linearly. Each of the one or more heaters may have a triangular or rounded triangular shape.

[0145] In another aspect, some embodiments of the present invention may provide a LiDAR transceiver, which includes a LiDAR transmitter PIC as described above and a LiDAR receiver PIC as described above.

[0146] The LiDAR transmitter PIC and / or LiDAR receiver PIC can be mounted on a photonic chip. The LiDAR transmitter PIC and LiDAR receiver PIC can be mounted on the same monolithic photonic chip.

[0147] The LO source can be provided by a light source. The LO source can be modulated or unmodulated. Receiving the LO source from the light source is a simple way to ensure that the LO source is coherent with the light received in the receiver.

[0148] The light source may include multiple lasers, each laser being configured to generate light of a corresponding different wavelength within a wavelength range, and the emitter may be a grating emitter configured to adjust light having wavelengths within a wavelength range to a corresponding azimuth component, and the transmitter PIC may be configured to simultaneously generate multiple corresponding different wavelengths of light, and the transceiver is configured such that the signal input and LO input of each coherent receiver carry light of the same wavelength within a wavelength range.

[0149] The light source can be configured to encode the light such that each corresponding wavelength of light has a different corresponding code. Each corresponding code can be a linear frequency modulated pulse or an amplitude modulated pulse. Alternatively, the light source can be an input waveguide suitable for connection to one or more external lasers and / or modulators as described above.

[0150] The LiDAR transceiver may further include: a first optics configured to convert light emitted from each OPA to a second polar angle range, the second polar angle range being smaller than the polar angle range of the FOV; and a second optics configured to redirect light from each OPA to a corresponding polar steering angle. The polar steering angle may be ±ny, where n is an integer and y is the size of the second polar angle range. The polar angle range of the FOV may be ±45 degrees, and / or the second polar angle range may be ±3.75 degrees.

[0151] A LiDAR receiver may include a LiDAR receiver PIC as described above, as well as a plate and a wedge. The wedge has a front surface and an opposing rear surface. An imaging component is arranged to define a received optical path through the front surface of the wedge, and the received optical path continues through the wedge and through the plate to the PIC receiver. A LiDAR transceiver may include a LiDAR receiver and a LiDAR transmitter PIC as described above. The transceiver is arranged to define a transmitted optical path from the transmitter through the wedge and through the front surface of the wedge. The PIC receiver may be located behind the rear surface of the plate, and the end surface of the plate away from the wedge may form an angle of less than 90 degrees with the rear surface of the plate, such that the received optical path exits the rear surface of the plate toward the PIC receiver.

[0152] Alternatively or concurrently, the lens may be located on the rear surface of the plate at the end of the plate away from the wedge, and may be formed of one or more microlenses. One or more lenses may be disposed between the plate and the PIC receiver. The lens may be integrated into the wedge and / or the plate and / or the diffractive optics.

[0153] One or more lenses may be circular, elliptical, or cylindrical, or the lenses may be formed from a microlens array. The microlens array may be integrated into the bottom surface of the board and may be formed by etching the bottom surface of the board. One or more additional lenses having any of the above-described characteristics may also be provided. The PIC receiver may have one or more input waveguides, and each microlens may be configured to focus light onto a corresponding input waveguide.

[0154] The imaging component may have a diffractive optical element on the front surface of the wedge, such that the received optical path extends through the diffractive optical element, through the front surface of the wedge, through the wedge and the plate to reach the PIC receiver.

[0155] By utilizing the geometry of wedges and plates, the optical path of the LiDAR receiver can be folded, allowing the imaging components to be manufactured thinner. Using a wedge and plate arrangement, light can be guided into a waveguide-based receiver while controlling the phase front of the collected light to achieve high coupling efficiency within the waveguide. In systems purely based on detecting the power of reflected light, maintaining the phase of the reflected light through receiving optics is not necessary; however, when the reflected light is to be coupled into a PIC waveguide, controlling the phase front of the collected light may be required to achieve high coupling efficiency within the waveguide. Advantageously, the wedge and plate arrangement is suitable for either application.

[0156] The wedge arrangement in some embodiments of the present invention means that the thickness of the optics can be significantly reduced. The provided wedges, plates, any lenses and / or diffractive optical elements are used to focus, concentrate and deflect the received light while maintaining phase fronting in order to provide good coupling to the PIC waveguide of the receiver.

[0157] Furthermore, in existing technology systems, it is impossible to position the receiver and transmitter PICs close enough together to avoid parallax effects without using wedges. By implementing a wedge and plate arrangement, the receiving and transmitting optical circuits can be spatially separated while avoiding parallax problems. The receiver and transmitter can be spatially separated. They can be held on a single die or located on separate dies. Moreover, this arrangement allows for the coupling of received light into the receiver PIC waveguide while maintaining the phase of the light. This can be advantageous for applications such as FMCW and PMCW LiDAR systems.

[0158] Use wedges and plates (examples are shown in...) Figure 33 As shown in the diagram, the received light is guided away from the path of the emitted light while still maintaining the received light and the transmitted light coaxial at the surface, where the light is transmitted into / received from the environment being scanned.

[0159] According to another aspect, some embodiments of the present invention can provide a LiDAR emitter photonic integrated circuit (PIC) for scanning an environment over a field of view (FOV) having an azimuth range and a polar range. The LiDAR emitter PIC includes: a light source; an optical switch having an input and a plurality of outputs, the optical switch being configured to selectively direct light received at the input to one of the plurality of outputs; and a light-emitting element having a plurality of inputs and a plurality of emitters, the light-emitting element being configured to selectively emit beams at a plurality of emission angles having different corresponding polar components within the polar range of the FOV. The light source is coupled to an input of the optical switch, and each of the plurality of outputs of the optical switch is coupled to a corresponding one of the plurality of inputs of the light-emitting element, such that the optical switch and the light-emitting element form a switching matrix, and the switching matrix is ​​configured to select the polar components of the emission angle of light within the polar range.

[0160] Using a switching matrix means that a combination of slow and fast switching elements can be used to achieve high switching speeds between points to be sampled. For example, if the light-emitting element is a slow-switching element and the optical switch is a fast switch, a fast switching speed for the entire switching matrix can still be achieved because the slow-switching portion of the light-emitting element can be switched while other portions of the light-emitting element are emitting light. In this way, the non-emitting portions of the light-emitting element can be switched using the sampling time of one or more of the emitting portions of the light-emitting element without affecting the total switching time between emission angles.

[0161] For example, in the simple case of a light-emitting element with four emission angles and two inputs, an optical switch can direct light to the first input of the light-emitting element, which corresponds to the first portion of the light-emitting element emitting at a first emission angle, while the second portion switches to the second emission angle. Then, the optical switch can direct light to the second input of the light-emitting element, causing the light to emit at the second emission angle, while the first portion of the light-emitting element switches to the third emission angle. Then, the optical switch can direct light to the first input of the light-emitting element, causing the light to emit at the third emission angle, while the second portion of the light-emitting element switches to the fourth emission angle. Then, the optical switch can direct light to the second input of the light-emitting element, causing the light to emit at the fourth emission angle, while the first portion of the light-emitting element switches back to the first emission angle. In this way, the switching time of the entire matrix is ​​the switching time of the optical switch (which is a fast switch), and the slow switching of the light-emitting element does not slow down the sampling of the FOV.

[0162] When the optical switch is slow and the light-emitting component is fast, the switch will remain in the first position for a time (N t). pixel +N t lec ), where N is the number of pixels sampled by the light-emitting component when the switch is in the first position. Then, the optical switch will... switch Internal switching. Therefore, the system is efficient because the number of slow switches is reduced. The efficiency will be (N t) pixel +N t lec ) / (N t pixel +N t lec +t switch Therefore, if t switch < <N×t pixel The system is therefore highly efficient.

[0163] When the OPA light-emitting component and / or switch includes a phase shifter as a heater, the switching time of the OPA can be determined by the time required to reconfigure the heater from one set of phase shifts to another. This can result in the OPA switch being a slow switch, as the heater may switch slowly due to the time spent on heat buildup or dissipation.

[0164] An optical switch can be a faster switch than a light-emitting component, or it can be a slower switch than a light-emitting component. A fast switch is one whose switching time is less than a pixel time. A pixel time is the length of time a LiDAR emitter spends sampling any specific point within its field of view (FOV). The switching time of an element is the time it takes for an element to reconfigure itself from one of its outputs to another.

[0165] The transmitter is configured to scan the emission angle array and emit light to each of the emission angles at a time (t) to reach a pixel. pixel ), and the optical switch is capable of switching at a time (t switch Switching between outputs in ) and t pixel >t switch .

[0166] The transmitter is configured to scan the emission angle array and emit light to each of the emission angles at a time (t) to reach a pixel. pixel ), and the optical switch is capable of switching at a time (t switch Switching between outputs in ) and t pixel <t switch .

[0167] The transmitter is configured to scan the emission angle array and emit light to each of the emission angles at a time (t) to reach a pixel. pixel ), and the light-emitting component is capable of switching at a time (t). lec In ) switching between extreme components, and t pixel >t lec .

[0168] The transmitter is configured to scan the emission angle array and emit light to each of the emission angles at a time (t) to reach a pixel. pixel ), and the light-emitting component is capable of switching at a time (t). lec In ) switching between extreme components, and t pixel <t lec .

[0169] The light-emitting element can be configured such that each input of the light-emitting element corresponds to a corresponding subrange of the polar angle range, such that the input determines the subrange of the polar angle from which light can be emitted from the light-emitting element, and the light reaches the light-emitting element at the input.

[0170] The light-emitting component may include at least one optical phased array (OPA), which or each optical phased array is configured to selectively emit a beam at one or more of a plurality of emission angles.

[0171] The light-emitting component may include a plurality of sub-light-emitting components, each sub-light-emitting component having one or more of a plurality of inputs to the light-emitting component, and each sub-light-emitting component corresponding to a corresponding sub-range of polar angle range, such that the sub-light-emitting component to which light reaches determines the sub-range of polar angle from which light may be emitted from the light-emitting component.

[0172] Optical switches can be configured to sequentially direct light to sub-emitting elements, such that each sub-emitting element receives light for a corresponding time (t). on Then, the light is not received for the corresponding time (t). off ), where for each sub-light-emitting component, t off ≥t lec .

[0173] Each sub-emitting element can be configured such that each input of the sub-emitting element corresponds to a corresponding sub-range of the polar angle range, such that the input determines the sub-range of the polar angle from which light can be emitted from the emitting element, and the light reaches the sub-emitting element at the input.

[0174] Each sub-light-emitting component can be an OPA.

[0175] The LiDAR transmitter PIC may also include multiple beam splitters, each having an input and multiple outputs, and configured to separate light received at the input among the multiple outputs, wherein each output of an optical switch is coupled to a corresponding input of the beam splitter, and each output of each beam splitter is coupled to a corresponding input of the transmitting element.

[0176] An optical switch can be a fast switch, and the light-emitting component can be a slow switching element. Conversely, an optical switch can be a slow switch, and the light-emitting component can be a fast switching element.

[0177] The light-emitting component may include one or more phase shifters, which may be one or more heaters. The light source may be formed by at least one laser.

[0178] According to another aspect, some embodiments of the present invention may provide a LiDAR system including a first scan stage for scanning in a first dimension and a second scan stage for scanning in a second dimension, the first scan stage including tuning and / or refractive optics; and the second scan stage including liquid crystal.

[0179] The present invention includes combinations of the foregoing aspects and preferred features, unless such combinations are obviously not permitted or explicitly avoided.

[0180] For example, optional features of the first, second, and / or third aspects can be combined with the fourth aspect. Any one or a combination of features of the imaging component of the first aspect can be combined with a transceiver according to any of the second, third, or fourth aspects. Furthermore, any feature of the LiDAR transmitter and / or receiver and / or transceiver PIC and / or its optional features can be combined with any feature of the first four aspects. Attached Figure Description

[0181] Embodiments and experiments illustrating the principles of the invention will now be discussed with reference to the accompanying drawings, in which:

[0182] Figure 1 An example of a prior art arrangement of lens, receiver, and transmitter is shown.

[0183] Figure 2 This is a diagram showing the coaxial arrangement of the receiving aperture and the transmitting aperture.

[0184] Figure 3A A cross-sectional view of the arrangement of diffractive optical elements, lenses, receiver OPA, and transmitter OPA is shown.

[0185] Figure 3B A schematic diagram is shown of a receiving optics device used to adjust and focus received light onto a photonic integrated circuit.

[0186] Figure 4 A schematic diagram illustrating the principle of using wedges and plates to collect light is shown.

[0187] Figure 5 Schematic diagrams of wedge-shaped members and plates, as well as examples of photonic integrated circuits (PICs), according to some embodiments of the present invention are shown.

[0188] Figure 6A Cross-sectional views of wedges and plates, lenses, and diffractive optical elements according to some embodiments of the present invention are shown, and Figure 6B Perspective views of wedges and plates, lenses and diffractive optical elements according to some embodiments of the present invention are shown.

[0189] Figure 7A Cross-sectional views of wedges, plates, and diffractive optical elements according to some embodiments of the present invention are shown, and Figure 7B A perspective view of a diffractive optical element is shown.

[0190] Figure 8 A perspective view of an example diffractive optical element (DOE) according to some embodiments of the present invention is shown, as well as partial cross-sectional views of the front and rear surfaces of the DOE.

[0191] Figure 9APerspective views of a PIC having a transmitter OPA and four receiver OPAs, a wedge and a plate, and a DOE are shown, along with perspective views of the wedge, plate, and DOE mounted on the PIC, according to some embodiments of the present invention. Figure 9B An example arrangement of chips including a PIC, transmitting and receiving optics, and control devices is shown.

[0192] Figure 10A and 10B A schematic diagram of a DOE according to some embodiments of the present invention is shown, illustrating the redirection of a beam with two different wavelengths. Figure 10A A perspective view of the DOE is shown, and Figure 10B A cross-sectional view of the DOE is shown.

[0193] Figure 11A and 11B A schematic diagram of a DOE according to some embodiments of the present invention is shown, illustrating the redirection of a beam with a single wavelength. Figure 11A A perspective view of the DOE is shown, and Figure 11B A cross-sectional view of the DOE is shown.

[0194] Figure 12 (i) shows a schematic diagram of a DOE according to some embodiments of the present invention, which illustrates the creation of three beams based on each beam arriving at the DOE.

[0195] Figure 12 (ii) A schematic diagram of a DOE according to some embodiments of the present invention is shown, illustrating the spread of the beam over a large field of view.

[0196] Figure 13A A schematic diagram of a LiDAR transmitter PIC is shown, and Figure 13B A schematic diagram of another LiDAR transmitter, PIC, is shown.

[0197] Figure 14 A schematic diagram of an OPA for use as a light-emitting component is shown.

[0198] Figure 15 A schematic diagram of a single-stage OPA transmitter is shown.

[0199] Figure 16A A schematic diagram of two 1×4 beam splitters is shown. Figure 16B A schematic diagram of a 2×8 beam splitter is shown.

[0200] Figure 17A A schematic diagram of a 1×24 optical switch formed by a tree of 1×2 optical switches is shown. Figure 17B A more detailed diagram of a 1×2MZI switch is shown.

[0201] Figure 18A A schematic diagram of a 1×24 optical switch is shown, which is formed by a tree consisting of 1×3 optical switches and 1×2 optical switches. Figure 18B A more detailed diagram of the 1×3MZI switch is shown.

[0202] Figure 19 A schematic diagram of a 1×24 optical switch formed by a 1×24 OPA-based switch is shown.

[0203] Figure 20 A schematic diagram of a 1×24 optical switch is shown, consisting of a 1×4 MZI switch and four switches based on a 1×6 OPA.

[0204] Figure 21 A schematic diagram of a LiDAR receiver PIC is shown.

[0205] Figure 22 A schematic diagram of a photonic lens for use in a receiver PIC is shown.

[0206] Figure 23 A schematic diagram of a set of coherent receivers for use in a receiver PIC is shown.

[0207] Figure 24 A schematic diagram of the arrangement of the light source used in the LiDAR transceiver is shown.

[0208] Figure 25 A schematic diagram of another arrangement of light sources used in a LiDAR transceiver is shown.

[0209] Figure 26 A schematic diagram of another arrangement of light sources used in a LiDAR transceiver is shown.

[0210] Figure 27 A schematic diagram of a tunable laser used in a light source is shown.

[0211] Figure 28 A schematic diagram of a tunable laser used in a light source is shown.

[0212] Figure 29 A schematic diagram of a tunable laser used in a light source is shown, wherein the RF current I RF1 to I RF8 It is input for use in FM chirping.

[0213] Figure 30 A schematic diagram is shown of an optical device used to cover the FOV of the emitter for adjusting the output of the light-emitting component.

[0214] Figure 31 A schematic diagram showing an example of an OPA setup covering a 45-degree by 45-degree field of view is provided.

[0215] Figure 32 An exploded view of an example of an optical device for guiding light in the azimuth direction based on wavelength is shown.

[0216] Figure 33 The construction of a transceiver PIC with wedge-shaped / plate folded optics and diffractive optical emission and collection optical elements is shown.

[0217] Figure 34 A schematic diagram of a laser and MUX setup for use in some embodiments of the invention is shown.

[0218] Figure 35 A LiDAR system incorporating a liquid crystal phase shifter according to the present invention is shown. Detailed Implementation

[0219] Aspects and embodiments of the invention will now be discussed with reference to the accompanying drawings. Other aspects and embodiments will be apparent to those skilled in the art. All references herein are incorporated by way of citation.

[0220] The effects of wedges and plates will now be explained in more detail. Figure 4 This is a theoretical example illustrating the effect produced in a wedge 2 and a plate 3 having a series of mirrors 4a-4g, which can be similar to the case in a wedge and a plate of a receiving / imaging component.

[0221] Depend on Figure 4 The beam of light, indicated by the arrow, is incident on the lens and grating 1, and enters the wedge 2 at the front surface 2a of the wedge, traveling to the rear surface 2b, where it is reflected by the mirror 4a. The rear surface 2b of the wedge is inclined from the front surface 2a, so when the beam is reflected by the mirror 4a, it is guided toward the plate extending from the thicker end of the wedge. After being reflected by the mirror 4a, the beam travels back through the wedge 2 to the front surface 2a, where it is reflected by the mirror 4b, then travels through the wedge 2 and the plate 3, being reflected by the mirrors 4c, 4d, 4e, 4f, and 4g on the front surfaces 2a, 3a and the rear surfaces 2b, 3b of the wedge and the plate.

[0222] When the incident beam is reflected from a sequence of non-parallel mirrors, the angle of the beam relative to the vertical line of the top surface increases, and the beam is deflected and can travel a long working distance. This principle can be achieved using three long, continuous mirrors (instead of a series of discrete mirrors) on the front and rear surfaces of the wedge 2 and the plate 3.

[0223] In the wedges and plates of the imaging / receiving components Figure 4The mirror in the theoretical example is formed by the front and rear surfaces of the wedge 2 and the plate 3. Surfaces 2a, 2b, 3a, and 3b can reflect light using total internal reflection (TIR), or one or more of the surfaces can be coated with a high reflectivity (HR) coating.

[0224] A TIR reflector can be used instead of the mirror on the front surface 2a of the wedge to allow light to enter the wedge. The front surface 2a of the wedge 2 can have an anti-reflective (AR) coating to improve the coupling of light into the wedge. The light is then retained in the wedge 2 because the angle of incidence on the front surface 2a has been increased by reflection from the inclined rear surface 2b of the wedge when the light returns to the front surface. Depending on the materials and angles used, the TIR can also be used on one or more of the other surfaces 2b, 3a, 3b. For example, the HR coating on the front surface 3a and rear surface 3b of the plate can be omitted, where the TIR is used to retain light in the plate.

[0225] The wedge and plate structure allows incident external light to couple into the wedge, but then be trapped in the wedge and plate as it strikes the front surface of the wedge at an increasing angle to the normal, where that angle exceeds the critical angle of TIR.

[0226] If the bottom angled reflector is HR-coated (independent of TIR), the wedge angle can be at least half the TIR critical angle used for the wedge material to retain light within the wedge. For a TIR-dependent bottom surface, the wedge angle can be at least equal to the TIR critical angle in the wedge material to retain all light within the wedge. To make the wedge thinner, a small wedge angle can be used, and therefore an HR coating on the rear surface of the wedge can be used, as it results in a smaller wedge angle and a thinner wedge. The front surface of the wedge can also have a deflecting film.

[0227] Figure 5 The diagram illustrates a typical implementation of a wedge, where the wedge 2 is made of a high-index material (e.g., Si) with an index of 2 or greater to produce TIR with a small critical angle. The bottom surface 2b is coated with a high-reflectance (HR) coating (e.g., metal or multilayer), and the top surface 2a is coated with an anti-reflection (AR) coating to allow all incident light to pass through the wedge material. The AR coating does not affect the TIR properties of the interface. For Si, the critical angle is approximately 16.8°, so the wedge angle is approximately 8.4°. For a 10 mm trapping aperture A, the wedge thickness increases like the tangent of the wedge angle, and in this case is 1.5 mm thick and 20-40 mm long, so the use of the wedge and plate will fold in a height of 20-40 mm, which is, for example, Figure 3B The thickness may need to be 1.5mm in the arrangement.

[0228] like Figure 5As shown, plate 3 extends from wedge 2, allowing beams b1 and b2 to propagate through the wedge and through the plate. Due to multiple reflections from the rear surface 2b of the wedge, beam b1 will propagate at a more horizontal angle in plate 3, producing a beam that propagates closer to horizontally with each reflection, unlike beam b2, which propagates at a steeper angle to the horizontal in plate 3 because it has seen less reflection from the rear surface 2b of the wedge. Therefore, beam b1 propagates longer in wedge 2 but less in plate 3 (because it is more horizontal), while beam b2 propagates less in wedge 2 and more in plate 3. The total propagation distance of beam b1 entering from the thin side of the wedge can be approximately equal to the total propagation distance of beam b2 entering from the thick side of the wedge, depending on the lengths of the wedge and the plate. In this case, equal distances mean that the difference between the distances is less than the depth of focus of the lens.

[0229] At the end of the plate, the beam is reflected from an end surface 3c, which is angled to direct the beam toward the rear surface 3b and out of the plate to the PIC. The end surface 3c may be HR-coated or may rely on TIR to reflect the beam toward the rear surface 3b. If the rear surface 3b is HR-coated, gaps may exist in the HR coating to allow light reflected from the end surface 3c to pass through it. Regardless of whether the rear surface 3b has an HR coating or relies on TIR, an AR coating may be provided on a region of the rear surface 3b through which light is transmitted to the PIC receiver to maximize light transmission through the rear surface 3b once reflected from the end surface 3c.

[0230] When a wedge and plate arrangement is used in a transceiver, the received light can travel through the wedge and plate to fold the working distance as described above. However, this may not be necessary for emitted light that does not have an equivalent working distance to fold. Therefore, the emitted light can travel through the wedge instead of the plate. For example, the light can follow an emitted optical path from the PIC transmitter 8 to the rear surface of the wedge 2b, through the wedge 2, and out of the front surface of the wedge 2a. This can be achieved... Figure 6A and 7A As seen in the image. To reduce the loss of emitted light, a physical aperture can be provided by the wedge 2, or a virtual aperture can be provided by the wedge 2 by locally changing the coating on the rear surface 2b of the wedge 2 from an HR coating to an AR coating, wherein the emitted beam propagates through the wedge 2.

[0231] To ensure coaxial transmission and reception optical paths, thereby avoiding parallax errors, the transmitted beam passes through the center of wedge 2, such as... Figure 6A and 6B As shown.

[0232] In other embodiments, the transmitter may be provided separately from the imaging component. In such embodiments, a virtual or real aperture in the wedge is unnecessary, and therefore light loss in the received light within the wedge is reduced. In this case, the received and emitted light may not be coaxial, and the system can be configured to account for parallax error during the processing of the received signal. In these embodiments, the wedge and plate arrangement can be used to offset the PIC receiver away from the PIC transmitter. In these embodiments, the wedge and plate arrangement still provides the advantage of working distance folding and therefore a reduced system height.

[0233] exist Figure 6A and 6B The diagram illustrates the use of wedges and plates in 3D laser imaging components, as well as lenses and DOEs. Lenses and DOEs will be explained in more detail later. In some embodiments, the DOEs and lenses described herein can be used without wedges and plates, for example in applications where the thickness of the transceiver may be significant.

[0234] exist Figure 6A and 6B In the example shown, DOE 5 and lens 6 are mounted on the front surface 2a of the wedge. Emitter 8 uses wavelength scanning to scan the vertical or azimuth range (in... Figure 6A and 6B In the page plane of the cross-section shown), and using OPA to scan the horizontal or polar angle range (in Figure 6A and 6B The plane perpendicular to the page in the cross-section shown guides the light. The light follows the optical path from the emitter 8 through the correction optics and then enters the wedge 2 at the rear surface 2b. The light then travels through the wedge 2 and exits at the front surface 2a. The light then travels through the lens 6 and DOE 5, where multiple beams of different wavelengths are generated in the vertical direction by diffraction by adjusting the azimuth component of the light according to its wavelength.

[0235] In other examples, holes can be provided in the wedge to prevent the emitted beam from entering the wedge. Figure 6A and 6B In the example, the emitted optical path travels through the center of the front surface of the wedge.

[0236] Reflected light from multiple directions reaches the front surface of DOE 5 and travels through DOE 5 and lens 6 to the front surface 2a of the wedge. In this example, the receiving optical path area on the front surface of the wedge is located on the opposite side of the emitted optical path on the front surface of the wedge in the longitudinal direction of the wedge, such that on the front surface of the wedge, the receiving optical path area is closer to the thin end of the wedge than the emitted optical path area, and the receiving optical path area is farther away from the thin end of the wedge than the emitted optical path area.

[0237] The light then travels through the wedge to the rear surface 2b, where it is reflected due to TIR or the HR coating on the rear surface. The rear surface of the wedge slopes from the front surface, thus guiding the light toward the thick end of the wedge and the plate 3 in the manner described above. At the end of the plate furthest from the wedge, the light is guided toward the rear surface of the plate via end surface 3c, which forms an interior angle of less than 90 degrees with the rear surface 3b of the plate. The light then leaves the plate and travels toward the receiver. In this example, the receiver comprises four OPAs.

[0238] exist Figure 6A and Figure 6B In the example, wedge 2 and plate 3 can be made of silicon, and plate 3 is 0.5 mm to 2 mm thick. The thickness of the optics from the rear surface of the plate to the front surface of DOE 5 is between 2 mm and 4 mm. The width of the optics is between 5 and 20 mm, for example, between 5 and 10 mm. In other embodiments, different sizes can be used to suit the transceiver application.

[0239] Figure 7A The similar use of wedge 2 and plate 3 in 3D laser imaging receiver optics is shown in DOE15. Figure 7A The 3D beam steering in the process uses one or more OPAs in the first dimension (as the polar angle range of the FOV) and the second dimension (as the azimuth range), and is handled by varying the wavelength of the laser and diffraction from DOE 15.

[0240] Figure 7A Wedge 2 and plate 3 are shown, formed as a single integrated component. The end surface 3c of the plate furthest from the wedge forms an interior angle of less than 90 degrees with the rear surface 3b of the plate. End surface 3c may be coated with an HR coating to form a reflector. Receivers including four receiver OPAs 7 are located behind the rear surface 3b of the plate on the PIC. Transmitter OPA 8 is located behind the rear surface 2b of the wedge on the PIC. DOE 15 is located at the front surface 2a of the wedge and has a transmission area 15t and four receiving areas 15r1, 15r2, 15r3, and 15r4. The DOE will be described in more detail below.

[0241] exist Figure 7A In the example, the plate and wedge have a height of less than 1 mm, a length of approximately 20 mm, and a width of approximately 10 mm. DOE 15 is mounted on the front surface of the wedge 2. The DOE surface is approximately 10 mm × 10 mm. In other embodiments, different sizes can be used to suit the transceiver application.

[0242] The received light reaches the front surface of DOE 15 and passes through the receiving areas 15r1, 15r2, 15r3, and 15r4 of DOE 15 to the front surface 2a of wedge 2. The light then passes through the wedge to the rear surface 2b, where it is reflected either via TIR or due to the HR coating on the rear surface. As described above, the light is guided toward the plate due to the inclination of the rear surface 2b of the wedge. The light then passes through wedge 2 and plate 3 and is maintained within the wedge and plate by reflections from the front surfaces 2a and 3a and the rear surfaces 2b and 3b of the wedge and plate. When the light reaches the end of the plate furthest from the wedge, it is reflected from the end surface 3c and guided toward the rear surface 3b of plate 3. The light then leaves plate 3 and is transmitted to receiver OPA 7.

[0243] The light to be transmitted is transmitted from the emitter OPA 8 to the rear surface 2b of the wedge and enters the wedge. If an HR coating is applied to the rear surface 2b of the wedge for the purpose of retaining the received light within the wedge, this coating may not be present in a region of the rear surface of the wedge through which the light to be transmitted passes, allowing the light to effectively enter the wedge. The light then passes through the wedge 2 to the front surface 2a and exits the wedge. Finally, the light passes through the transmission region 15t of the DOE and enters the environment to be measured.

[0244] Figure 9A A wedge and plate are shown on top of a PIC 10 to collect light, focusing it onto one or more receiver OPAs 7. The PIC 10 includes four receiver OPAs 7 and a transmitter OPA 8. A wedge 2 and a plate 3 are positioned on the PIC such that the wedge 2 covers the transmitter OPA 8, and the end of the plate covers the receiver OPA 7. A DOE 15 is located on the front surface of the wedge 2. The DOE 15 is located at the front surface 2a of the wedge and has a transmission area 15t and four receiving areas. The DOE will be described in more detail below. This arrangement provides low-profile collection and emission optics.

[0245] The received light reaches the front surface of DOE 15 and, through the receiving area of ​​DOE 15, reaches the front surface of wedge 2, then through the wedge and the plate, as described above. When the light reaches the end of the plate furthest from the wedge, the light is reflected from the end surface 3c and guided toward the rear surface 3b of the plate 3. The light leaves the plate 3 and is transmitted to the receiver OPA 7. In other embodiments, different types of receivers (one or more) may be used instead of OPA 7.

[0246] The light to be transmitted is transmitted from the emitter OPA 8 to the rear surface of the wedge and enters the wedge. If an HR coating is applied to the rear surface 2b of the wedge for the purpose of retaining the received light within the wedge, the coating is absent in a region of the rear surface of the wedge, through which the light to be transmitted passes, allowing the light to be transmitted into the wedge. The light then passes through the wedge 2 and exits the wedge via its front surface. Finally, the light passes through the transmission region 15t of the DOE and enters the environment to be measured.

[0247] In this example, the transmitter OPA 8 and receiver OPA 7 have corresponding designs, for example, the same number of arm waveguides and the same number of input and output waveguides. The receiver and transmitter OPAs can be controlled using the same control element (e.g., a DAC). They are used to transmit / receive simultaneously in the same direction, i.e., they remain aligned. In this example, the OPAs are 1D and handle scanning within the polar angle range. The scanning azimuth range does not require active control because the wavelengths transmitted from the transmitter will be naturally recovered by the same grating at that vertical angle when returning to the receiver. The azimuth is encoded in wavelength.

[0248] Figure 9B An example arrangement of a chip 30, including a PIC 10, transmitting and receiving optics 35, and a control device 36, is shown. The PIC 10 has a transmitting block 32 and a receiving block 33, as well as a beam steering and receiving block 34 including a transmitter OPA and a receiver OPA. The control device 36 may be an electronic integrated circuit (EIC) that can control, drive, receive outputs from the optical components, and / or provide a data interface for the optical components. The PIC 10 and the control device 36 are mounted on a substrate such as a PCB, and the transmitting and receiving optics 35 are mounted on the PIC. The transmitting and receiving optics include a plate 3, a wedge 2, and a DOE 15, such as... Figure 9A As shown, a wedge covers the transmitter OPA, and a board covers the receiver OPA. Light from the transmitter OPA travels through the wedge and the DOE, and received light travels through the DOE, through the wedge, through the board, and reaches the receiver OPA. In this example, four receiver OPAs are provided and one transmitter OPA is used, but in other examples, the number of OPAs can be selected to match performance requirements. Furthermore, other types of transmitters and receivers can be implemented depending on performance requirements. The transmitter block 32 on the PIC 10 includes a laser and a waveguide to generate light to be emitted by the transmitter OPA. The receiver block 33 on the PIC 10 contains photonic circuitry for processing the light received by the receiver OPA. The chip 30 can be approximately 5 to 10 mm wide, but its size can vary depending on performance requirements.

[0249] Figure 3A and 3BThe lens and DOE shown can be used in combination with wedges and plates according to some embodiments of the invention. The receiver is an OPA receiver, and the transmitter shown is an OPA transmitter, but other types of receivers can be used. The OPA shown is a 1D OPA, meaning that all waveguide facets are on a single line (parallel to...). Figure 3B (x-axis in the diagram). Figure 3A and 3B In this process, DOEs and lenses are used. Figure 3B In the example shown, the received light passes through the DOE before passing through the lens. Other arrangements of DOE(one or more) and lenses(one or more) can be used instead of or added to those arrangements shown depending on the application requirements (e.g., changes can be made to adjust range or resolution). Solutions in which the received light passes through the lens first and then through the DOE can also be considered, although in the latter case the DOE may be more complex.

[0250] Lenses can be used to image all light incident on the lens aperture (~10mm × 10mm) into a spot size (10μm × 10μm or smaller) optimized for coupling into the PIC waveguide. In the xy-plane, the position of the image of the received light will depend on the angle of incidence in the xy-plane, as determined by... Figure 3B As shown. Typically, the focal length of a lens with an aperture diameter D (e.g., 10 mm) is at least four times the aperture diameter (or 40 mm in our example). Since the received light comes from a sufficiently far location for most imaging applications, it can be approximated as a plane wave, and the focused image will be at the working distance, which, for all practical purposes, is equal to the focal length. For this example, the achievable spot size for a lens with D = 10 mm and f = 40 mm has an FWHM of approximately 5-6 μm (for wavelengths in the 1550 nm range and spot size measured in air).

[0251] The lens can be located in front of the front surface of the wedge, such as... Figure 4 Figure 7 Figure 8 and Figure 9A As shown. The lens can be positioned between the DOE and the front surface of the wedge, as... Figure 6A and 6B As shown, it can be integrated with DOE, such as Figure 4 As shown in 7 and 9A, it can also be located in front of the DOE, which is located in front of the front surface of the wedge. When the lens is integrated into the DOE, it can be integrated as a Fresnel lens, such as... Figure 7A and 7B As shown.

[0252] The lens does not need to be circular, which means that in some embodiments, the focal length in the xy plane is the same as the focal length in the yz plane. One of the two focal lengths can even be infinite, causing the cylindrical lens to operate in either the yz or xy plane.

[0253] Alternatively, another lens, possibly cylindrical or a microlens array, can be used between the rear surface of the plate and the receiver. The cylindrical lens can operate along the same dimension as the first lens or in other dimensions.

[0254] As described above, one or more optical components, such as a DOE, can be provided in a LiDAR system to adjust, focus, and / or correct the light to scan the field of view (FOV) in the desired manner. The receiving area of ​​the DOE can also adjust the azimuth component of the received light based on the wavelength of the light.

[0255] To adjust light in a LiDAR system with coaxial transmit and receive optical paths, a DOE (Diffraction Optical Array) can be provided, having a transmission region at its center and receive regions distributed on opposite sides of the transmission region. The DOE has a front surface and a rear surface opposite the front surface, and emitted light travels from the rear surface through the DOE to the front surface, while received light travels from the front surface through the DOE to the rear surface. The DOE can be formed from more than one individual component. The transmission region may include an air-to-air grating to create multiple beams from a single beam from the emitter. The DOE may also include lens elements and / or correction optics in the transmission and / or receive regions. The diffractive optics described herein can be produced by 3D laser lithography. The receive region may be provided by 90% or more of the DOE.

[0256] The receiving area adjusts the light received at the front surface of the DOE to the output angle at the rear surface of the DOE. The degree of light redirection depends on the wavelength.

[0257] The receiving area can be adjusted according to the wavelength ( Figure 3B The plane (yz) in the image only adjusts the components of the light, such as the azimuth component of the light angle. The receiving area can be configured such that the polar components of the angle of the received light ( Figure 3B The plane (x, y) in the DOE is constant as light travels through it. Alternatively, the receiving area can be configured to change the polar components of the angle independently of the wavelength of the light.

[0258] In LiDAR systems that sample the field of view (FOV) using OPA and wavelength scanning methods, the azimuth component of the emitted light's angle can depend on the light's wavelength. Light reflects from the environment, and similarly, the azimuth component of the received light's angle depends on the light's wavelength. The receiving area of ​​the DOE is configured to adjust the azimuth component of the received light according to the wavelength so that received light from an azimuth range across the FOV has a common azimuth component, allowing it to be incident on a 1D OPA receiver, such as... Figure 10A and 10B As shown. The receiving area retains the polar components of the angle of the received light because the polar components of the angle of light depend on the orientation of the OPA in the transmitter and not on the wavelength. The polarization components can be spatially decoded by the OPA receiver. Multiple simultaneous beams from different polar angles and / or azimuth angles can be received at the DOE, and these beams can be simultaneously adjusted according to their wavelengths.

[0259] The transmission zone of a DOE can be configured to adjust the azimuth component of the light's angle according to its wavelength. The emitted light can alternatively or additionally be adjusted based on its wavelength by a grating emitter in a PIC emitter. Providing wavelength-dependent angles using a grating emitter in a PIC emitter may be more efficient than having this functionality in the DOE. In the transmission zone, the DOE can simply allow light to travel through it without interaction. The transmission zone can be configured to shape and / or improve the beam steering efficiency and / or correct the angle of emitted light traveling from the rear surface to the front surface.

[0260] The operation of the receiving area of ​​the DOE and lens is controlled by Figure 3B as well as Figure 10A and 10B As shown. Figure 3B The top-left image shows a view of the DOE, lens, and PIC from the field of view. The xz plane is parallel to the front surface of the DOE. The top-right image shows a side cross-sectional view of the DOE, lens, and PIC through the second plane (labeled xy), where light is guided by the OPA in the emitter. The bottom-left image shows a side cross-sectional view of the DOE, lens, and PIC through the first plane (labeled yz), where light is guided according to its wavelength. The xy plane shows how the polar components of the light are adjusted, and the yz plane shows how the azimuth components of the light are adjusted.

[0261] The dashed arrows depict light arriving at the DOE from the first position in the FOV, with the azimuth component W1 and the polar component O1. The solid arrows depict light arriving at the DOE from the second position in the FOV, with the azimuth component W2 and the polar component O2.

[0262] As shown in the upper right figure, the polar component of the light angle determines the location where the light reaches the PIC receiver. The polar angle in the FOV from which the received light originates is encoded in the location of the light at the receiver.

[0263] As shown in the lower left figure, the DOE adjusts the azimuth component of the light so that the beam has a common output azimuth component. Light is received from different azimuth angles of incidence depending on the wavelength of the light, and the DOE adjusts the light based on the wavelength in a manner complementary to the DOE's PIC emitter and / or transmission zone, such that light of different wavelengths exits the rear surface of the DOE with a common azimuth component. The DOE may include lens features to focus the received light onto one or more receivers. In this case, the output azimuth component of the light received from the DOE may depend on the position on the DOE to focus the light onto the receiver, but the output azimuth components are still considered common because they are directed to a common receiver.

[0264] The lens focuses the light onto the receiver. The wedge and plate can also be positioned between the lens and the PIC in the manner described above.

[0265] Therefore, both the first and second beams (solid and dashed arrows) arrive at the same receiver on the PIC. The azimuth component of the incident angle of each beam (W1 and W2) does not affect the position of the received beam on the PIC. The azimuth in the FOV from which the received light originates is encoded in the wavelength of the light and / or the chirp of the beam given to the PIC transmitter.

[0266] The azimuth component of the incident angle (yz plane) corresponds to the wavelength of light, and the grating in the DOE converts the azimuth (yz) incident angle component into a single back grating azimuth component independent of the wavelength (in... Figure 3B (As shown in the lower left figure, vertical). Therefore, the lens focuses all incident azimuth angles in the yz plane onto a single line (shown as parallel to the x-axis, which is perpendicular to the x-axis). Figure 3B (in the yz plane).

[0267] The grating does not need to operate along the z-axis in the yz-plane; it can operate along the x-axis in the xy-plane. The grating operates in a plane where the steering angle is controlled by the wavelength. When using a wedge, the direction of the wedge's length can be in a direction where the azimuth angle can be adjusted. In this way, the DOE can be configured such that the common output azimuth component is at an angle perpendicular to the front surface of the wedge and tilted towards the thick end of the wedge, so that all light remains within the wedge. A grating can be used in one direction, while a cylindrical lens is used in the orthogonal direction.

[0268] Figure 10A and 10B The diagram illustrates the receiving area of ​​the DOE, which shows eight incident beams. Figure 10A A schematic perspective view of the DOE receiving area and receiver, as well as two sets of beams, is shown. The sets have different wavelengths and different incident azimuth components. Each set has four beams with different polar angular components. Figure 10B A cross-sectional view showing the azimuth component is presented.

[0269] exist Figure 10A and 10B In this configuration, eight beams are simultaneously incident on the DOE. The eight beams cover four different polar angular components (O1, O2, O3, O4) managed by one or more OPAPC transmitters and two different azimuth angles (W1, W2) generated by the diffraction of the beams in the transmission zone (not shown for simplicity) of the PIC transmitter and / or the DOE.

[0270] The DOE's receiving area adjusts the azimuth component of the beam according to its wavelength, ensuring that each of the azimuth components W1 and W2 is converted into the same output azimuth component. Therefore, all beams are guided to the same receiver. The origins of beams of different wavelengths are encoded in the wavelengths and / or codes generated in the transmitter, thus eliminating the need for spatial separation between beams of different wavelengths in the receiver. Maintaining distinct polar components allows beams with different polar components to be received at different locations on the OPA receiver, and in this way, the polar components of the incident angle of the received light can be determined.

[0271] The receiving area can include multiple sub-areas. Each of the sub-areas can be configured to adjust light received from a corresponding different azimuth or polar angle from the environment. This can be advantageous because each sub-area of ​​the DOE then only needs to handle a narrower angular range, which makes it easy to design each sub-area of ​​the DOE. If two sub-areas are used, each sub-area can be configured to adjust light received from a corresponding half of the FOV.

[0272] For example, if four sub-regions are provided, and the azimuth angle range of the FOV is from -90 degrees to +90 degrees with respect to the direction perpendicular to the receiving surface, then the first sub-region can be configured to adjust the light received from an azimuth angle between -90 degrees and -45 degrees with respect to the normal to the front surface of the DOE; the second sub-region can be configured to adjust the light received from an azimuth angle between -45 degrees and 0 degrees; the third sub-region can be configured to adjust the light received from an azimuth angle between 0 degrees and +45 degrees; and the fourth sub-region can be configured to adjust the light received from an azimuth angle between +45 degrees and +90 degrees. Simultaneously, an emission angle of + / -90 degrees may not be exactly possible; here we refer to an angle as close to 90 degrees as possible.

[0273] In another example, if four sub-regions are provided and the azimuth range of the FOV is from -45 degrees to +45 degrees, the first sub-region can be configured to adjust the light received from the azimuth angle between -45 degrees and -22.5 degrees with respect to the normal of the front surface of the DOE; the second sub-region can be configured to adjust the light received from the azimuth angle between -22.5 degrees and 0 degrees; the third sub-region can be configured to adjust the light received from the azimuth angle between 0 degrees and +22.5 degrees; and the fourth sub-region can be configured to adjust the light received from the azimuth angle between +22.5 degrees and +45 degrees.

[0274] In some embodiments, the transmission region of the DOE can be configured to separate the emitted light to generate multiple beams, each with a different azimuth component. In these embodiments, as one beam enters the DOE at the rear surface of the transmission region, multiple beams exit the front surface of the transmission region, each with a different azimuth component. This can be advantageous, for example, when the PIC emitter cannot generate a sufficiently wide wavelength range to cover the angular range of the desired FOV. The beams(one) emitted by the grating emitter(s)(s)(s) can each be split into multiple beams traveling in different directions, allowing sampling of the entire angular range of the desired FOV.

[0275] For example, if the PIC grating emitter can emit beams within a 15-degree angular range, and the desired field of view (FOV) is 45 degrees wide, the transmission area of ​​the DOE can be configured to split each beam into three beams, with the three created beams spaced 15 degrees apart. In this way, the entire desired FOV can be sampled.

[0276] This is Figure 12 As shown in (i), the beam is guided by a grating emitter in the PIC emitter over a first range of azimuth angles. The beam then reaches the rear surface of the DOE, and the DOE creates multiple beams from each beam traveling through the DOE to the front surface, the created beams being guided over a second, larger azimuth angle range. Figure 12 In (i), the DOE creates three beams from each beam that reaches the rear surface, such that the second azimuth range is three times wider than the first azimuth range.

[0277] When a DOE is used to create multiple beams of the same wavelength traveling in different directions, these multiple beams can remain separated as they are received via the receiving area of ​​the DOE. Therefore, the receiving area can be configured to tune the light from each of the multiple beams of the same wavelength to a different output angle, such as... Figure 11A and 11B As shown.

[0278] Figure 11AA schematic perspective view of the DOE receiving area and receiver, as well as two sets of beams with the same wavelength but different incident azimuth angles, and four beams with different polar angles in each set, is shown. Figure 11B A cross-sectional view showing the azimuth angle is provided.

[0279] In this diagram, eight beams are simultaneously incident on the DOE. These eight beams cover four different polar components (O1, O2, O3, O4) managed by one or more OPA PIC transmitters and two different azimuth components (W1, W2) already generated by creating the beams in the DOE's transmission zone (not shown for simplicity). The DOE adjusts the azimuth components of the beams according to their wavelengths, such that each of azimuths W1 and W2 is converted into a different output azimuth and thus directed to different receivers. When beams are created from transmission zones with the same wavelength but different azimuth components, the DOE's receiving zone directs these beams to different PIC receivers, making it possible to identify the direction from which the beams originate within the FOV.

[0280] In some embodiments, more than one wavelength can be received simultaneously, so that the mechanisms shown in Figures 10 and 11 occur simultaneously.

[0281] by Figure 11A and 11B The advantage of creating multiple beams in this way is that emitting multiple beams of the same wavelength at the same time means that several points in the field of view can be measured simultaneously, thereby improving the sampling rate.

[0282] A DOE can be designed with sub-regions arranged to receive and modulate light from one direction, and to transmit separate emitted beams in that direction via a transmission region of the DOE. In this way, multiple received beams can be modulated and focused onto different PIC receivers, such as those with... Figure 7A and 7B The OPA shows four different lenses, or a single larger receiving lens to collect more light. Since the four beams will have different azimuth components, they can be guided by the DOE to different receiver lines at the same wavelength (see [link to OPA diagram]). Figure 3A (x-rays in the image). In this way, the system can distinguish four beams by means of a receiver, which is focused onto the receiver.

[0283] The optical devices shown in Figures 6 and 7 each have a transmission region located in the emission optical path and a receiving region located in the receiving optical path. The transmission region is used to create multiple beams and / or adjust the light to be transmitted into the imaging environment and / or shape the light to be transmitted into the imaging environment. The receiving region is used to adjust the received light to ensure that it is guided to the PIC receiver. The transmission region can be located at the center of the DOE, and the receiving region can be located at other locations, such as... Figure 7A and 7B In all directions shown or only in such Figure 6A and 6B The transmission area is surrounded by the vertical direction (direction of the azimuth component) shown.

[0284] Figure 6A and Figure 6B The DOE shown in Figure 7 has four sub-receiving areas, each configured to adjust light from a different sub-range of the azimuth component within the FOV, so as to guide the light from that sub-range of the azimuth component to the corresponding receiver. Figure 6A and 6B In this configuration, receiving sub-regions and transmission regions are arranged linearly in the vertical direction (direction of the azimuth component), with two receiving sub-regions 5r1 and 5r2, followed by a transmission region 5t, and then two other receiving sub-regions 5r3 and 5r4. The sub-regions can be configured to direct light from a sub-range of their respective angles to a corresponding receiver among multiple receivers. This can be the case when the transmission region is used to create multiple beams with different azimuth angles, such that multiple beams with the same wavelength but originating from different azimuth angles each reach different PIC receivers. In other embodiments, the entire receiving region can be configured to direct light from any azimuth angle within the azimuth range of the FOV to a single receiver.

[0285] exist Figure 7A and 7B In this configuration, the transmission zone is located at the center of a square DOE, and four receiving sub-zones are arranged around the transmission zone, each located at a corresponding corner of the adjacent DOE.

[0286] exist Figure 6A and Figure 6B as well as Figure 3A In this DOE, there is a strip or rectangular area at the center that adjusts the incident beam from the transmitter, splitting it into multiple beams, correcting the direction and / or collimating it, and also providing azimuth wavelength dependence to adjust the multiple beams according to the transmitter wavelength. Because the emitted beam does not pass horizontally through the wedge, the operating distance of the transmitting optics can be much shorter than that of the receiving optics, for example, about 2-5 mm.

[0287] Phase plates can be used in DOEs to provide many degrees of design freedom, such as... Figure 7A and 7B (The lens function is integrated into the diffractive optical element) and Figure 8 As shown in the image. Figure 7A and 7B A single DOE is shown that combines wavelength dependence, beam shaping, focusing, spatial multiplexing, and beam splitting. Figure 8The diagram illustrates three functions that can be performed by the DOE through its two parts. In this example, the front surface 10a of the DOE is a wavelength-sensitive diffraction grating, and the rear surface 10b is a beam steering structure.

[0288] Note that wavelength-dependent gratings can be generated as blazed gratings, which can be considered as a series of refractive elements. Beam splitting and focusing (wavelength-independent functions) can best be generated using a stepped phase plate pattern, where each feature is a square of approximately 1 μm and up to a depth of one wavelength, such as... Figure 8 As shown. When designing such a phase plate, the number of depth steps in the phase plate is chosen to meet the required application FOV and resolution (in a similar manner to the selection of the number of emitters in an OPA). Steering and focusing elements can also be incorporated into the DOE or used as additional elements to guide light to the desired PIC receiver.

[0289] Figure 8 An example of a DOE is shown, illustrating that a DOE can be considered to have three separate functions. Figure 8 The example DOE shown has two separate element parts: the front surface provides a wavelength-sensitive diffraction grating, and the rear surface provides beam steering in a manner similar to an OPA. The rear surface of the DOE also provides beam focusing. In other examples, the wavelength-sensitive diffraction grating may be provided by the rear surface instead of the front surface. Beam steering may be provided by the front surface instead of the rear surface. Beam focusing may be provided by the front surface instead of the rear surface, or by both the front and rear surfaces. Alternatively, beam focusing may be provided by a separate lens, in which case the DOE may not provide beam focusing.

[0290] In some embodiments, optical devices such as lenses can be used to diffuse the emitted light to a larger field of view, such as... Figure 12 As shown in (ii). For example, this can be advantageous when the PIC transmitter cannot produce a sufficiently wide wavelength range to cover the angular range of the desired FOV. If the PIC transmitter can emit a beam within a limited angular range, and the desired FOV is a larger angular range, the transmission zone of the optics can be configured to increase the angle at which the emitted light travels. In this way, the entire desired FOV can be sampled.

[0291] For example, if the PIC grating emitter can emit a beam at a 15-degree angle, and the desired field of view (FOV) is 45 degrees wide, the transmission zone of the optics can be configured to triple the angle, with the emitted light traveling at said angle. In this way, the entire desired FOV can be sampled.

[0292] Figure 32An example of an optical device for guiding the azimuth component of light is shown. The lower component shows a receiving area and a transmitting area, with the transmitting area at the center and surrounded by the receiving area. This lower component is in front of one or more light-emitting components of the emitter(s), and may also be in front of a wedge-shaped component. The transmitting area is configured to collimate the light in the azimuth direction and narrow the extreme FOV of each OPA in the light-emitting component, for example, from 90 degrees to 7.5 degrees, resulting in a resolution of 0.1 degrees. The receiving area acts as a lens to focus the received light.

[0293] The intermediate component is a diffraction grating that adjusts the azimuth component of the light according to its wavelength. This effectively demultiplexes the azimuth component of the emitted light and multiplexes the azimuth components of the received light at different wavelengths.

[0294] The upper portion increases the azimuth component of the emitted light and decreases the azimuth component of the received light, thereby widening the field of view (FOV). For example, the azimuth component of the FOV can be increased from 15 degrees to 45 degrees, where the resolution decreases from 0.03 degrees to 0.1 degrees.

[0295] In one example, achieving 32 lasers tuned to a wavelength of 100 nm means each laser is tuned to approximately 3.2 nm. This can be achieved by heating a DBR laser to approximately 42 degrees Celsius using a silicon grating and a heater. Figure 12 Following method (i), a step size of 0.67 nm per point in the FOV achieves 150 different angles, providing an average pixel width of 0.1 degrees. Figure 12 Following method (ii), a step size of 0.22nm per point in the FOV achieves 450 different angles, which provides an average pixel width of 0.1 degrees.

[0296] Figure 13A An example of a transmitter PIC architecture for use in a LiDAR transmitter is shown. A light source 41, providing light from at least one laser, supplies light to an optical switch 42, which has inputs from the light source and multiple outputs supplying light to a light-emitting element 45. The light-emitting element 45 has multiple inputs and multiple emitters, and is configured to selectively emit beams at multiple emission angles within a FOVθ. FOV Within the polar angle range, there are different corresponding polar components.

[0297] Figure 13B An example of a transmitter PIC architecture for use in a LiDAR transmitter is shown. A light source 41, formed by at least one laser, supplies light to an optical switch 42, which has an input from the light source and multiple outputs that supply light to a beam splitter 43. The beam splitter 43 then supplies light to an OPA light-emitting element 45. Figure 13BThe example has a beam splitter, meaning that multiple beams can be emitted simultaneously in different directions, thereby increasing the sampling rate. However, in other embodiments, such as Figure 13A The embodiment shown may not require a beam splitter.

[0298] exist Figure 13B In the example, light source 41 is a tunable emitter that simultaneously provides four different wavelengths. This means that four azimuth angles can be sampled simultaneously, thereby improving the scanning speed of the LiDAR emitter PIC. In other embodiments, depending on the desired application, only one or any other number of wavelengths can be emitted simultaneously. In other embodiments, one or more lasers may be provided on a separate chip from other components, and the light source may be one or more input waveguides that can be connected to one or more individual lasers.

[0299] The light source is coupled to the switch via a waveguide that simultaneously carries four wavelengths. In other embodiments, the light source may provide only one or more wavelengths at any given time. The waveguide in the PIC may be capable of carrying multiple wavelengths simultaneously. The waveguide may be a broadband waveguide. Adjacent wavelengths may be separated by 30 nm.

[0300] The light source 41 also outputs an LO signal 13 with the same wavelength as one or more wavelengths output to the optical switch 42. The LO signal can be used by the receiver, and will be discussed in more detail below.

[0301] Figure 13B The LiDAR transmitter PIC has 1×24 switches, but in other embodiments, the number of outputs of (one or more) switches can be different and can be selected to suit the application.

[0302] Waveguides couple the switch outputs to the inputs of the beam splitters. Each output of the optical switch 42 is coupled to a corresponding input of the beam splitter 43. The outputs of the beam splitters are each coupled via waveguides to their respective inputs to the light-emitting element 45.

[0303] Figure 13B The light-emitting components include twelve OPAs, each with eight inputs and seventy-eight emitters. The inputs where light arrives determine the coarse direction in which it will be emitted, and the OPAs actively determine the fine output angle. Figure 13BIn this system, the OPA has a phase shifter to shift the phase of the light within the OPA, thereby guiding the beam along the desired polar angle. The phase shifter can be a triangular phase shifter, such as a triangular heater. Each OPA can guide light to sixty-eight different polar angles with a beamwidth of 1.2 degrees, thus giving each OPA a polar FOV close to 90 degrees (+ / - 45 degrees). Therefore, the total number of resolvable points using these OPAs is 816. Optical devices can be used to convert each of the OPA outputs to the desired polar angle as a whole θ. FOV The sub-range of the transmitter's extreme FOV.

[0304] In other embodiments, other numbers of OPAs can be used with different numbers of inputs and emitters. These properties of the OPA can be selected to suit the application of the emitter.

[0305] Figure 14 An example of an OPA used in a light-emitting component is shown. An input waveguide 46 is coupled to a Gaussian beam splitter 47, which is coupled to an array of path-matched arm waveguides 48. Triangular phase shifters 49 are arranged to cause a phase shift across the arm waveguides 48. Each arm waveguide is coupled to a corresponding fan-in waveguide 50, which is coupled to a corresponding path-length matched emitter 51. The phase shift imparted by the triangular phase shifters 49 in the arm waveguides affects the emission angle of the light from the emitter 51. The Gaussian beam splitter is a 99% cutoff beam splitter. Power for the triangular phase shifters 49 is provided at I1 and I2.

[0306] Figure 14 The example shown has eight inputs, 78 arm waveguides, and 78 emitters, which can guide light at 68 different polar angles with diffraction limitation. Each of the eight inputs 46 of the OPA covers + / - 5.6 degrees (11.25-degree range) of the OPA's field of view (FOV), and the phase shift imparted in the arm waveguides 48 is used to select a fine direction for imparting light within this range. In other embodiments, the FOV of the OPA can be separated differently.

[0307] Figure 14 The triangular phase shifters 49 are arranged "from top to bottom" and are capable of phase shifts up to 10 pi. For light at a wavelength of 1550 nm, the emitters have a 1.1 μm pitch for a field of view (FOV) of + / - 45 degrees. The beamwidth emitted at 0 degrees is 1.2 degrees. The emitters are grating emitters to allow wavelength redirection, which will be discussed in more detail below.

[0308] Using an OPA with multiple inputs and using multiple OPAs each reduces the complexity of the components required for adequate sampling of the LiDAR transceiver's field of view (FOV). For comparative purposes, Figure 15 A single-stage OPA transmitter is shown in the figure.

[0309] The OPA has an input waveguide 46 coupled to a Gaussian beam splitter 47, which is coupled to an array of path-matching arm waveguides 48. Individual phase shifters 52 are arranged to cause a phase shift across the arm waveguides 48. Each arm waveguide is coupled to a corresponding one of the fan-in waveguides 50, and each fan-in waveguide 50 is coupled to a corresponding one of the path-length-matching emitters 51. The phase shift imparted by the phase shifters 52 in the arm waveguides completely determines the emission angle of the light from the emitters 51. The phase shifters may be heaters.

[0310] Figure 15 The example in the example has one input, 912 arm waveguides, and 912 emitters, which can guide light at 810 different polar angles with diffraction limitations. There are 912 2pi phase shifters, each requiring a control signal. The phase shift assigned in arm waveguide 8 is used to select the direction across the entire FOV of the OPA.

[0311] The diagram shows the relationship with Figure 14 Compared to single-stage OPAs, which require more complex electronics and system control, this layered architecture offers a more complex FOV (field of view) of + / -45 degrees for 1550nm wavelength light. Figure 15 The OPA in the image has emitters with a spacing of 1.1 micrometers. The 912 emitters provide 810 diffraction-limited points, resulting in a beam width of 0.1 degrees at 0 degrees. The emitters are related to... Figure 14 The grating emitter and the waveguide support four wavelengths to allow wavelength steering in the azimuth direction.

[0312] like Figure 14 As shown, multiple inputs can be provided to the light-emitting component simultaneously (see the dashed and solid lines indicating simultaneous inputs at inputs 1 and 8). This can be achieved using a beam splitter. The same beam splitter(s) can be used for selection in the receiver, which will be discussed in more detail below.

[0313] To better separate simultaneous beams, a beam splitter can be coupled to the light-emitting component, preventing simultaneous beams from being sent to adjacent inputs. Figure 14 In the example, this means that the beams are 22.5 degrees apart when received at two inputs that are separated from each other (e.g., inputs 1 and 3), and therefore easier to distinguish at the receiver than when the beams originate from adjacent light-emitting component inputs (which would mean the beams are only 11.25 degrees apart).

[0314] exist Figure 16AAn example of this separated configuration that allows for simultaneous beam firing is shown. In this example, two 1×4 beam splitters 43a and 43b are shown, with output waveguides O1-8 crossed to alternately couple to the inputs of the light-emitting components. Due to the input from optical switch 42, at most one of the beam splitters 43a and 43b will be supplied with light at any given time. If the top beam splitter 43a is supplied by the optical switch, outputs O1, O3, O5, and O7 will supply their corresponding light-emitting component inputs, and if the bottom beam splitter 43b is supplied by the optical switch 42, outputs O2, O4, O6, and O8 will supply the light-emitting components.

[0315] exist Figure 16B An alternative beam splitter 43c is shown. Here, the beam splitter is a 2×8 MMI, where two inputs I1, I2 supply eight outputs O1-8 via interference in the beam splitter. Due to the input from optical switch 42, at most one of inputs I1, I2 will be supplied with light at any given time. If the top input I1 is supplied by the optical switch, outputs O1, O3, O5, and O7 will supply their corresponding light-emitting component inputs, and if the bottom input I2 is supplied by the optical switch 42, outputs O2, O4, O6, and O8 will supply light with respect to the light-emitting components.

[0316] Other types of beam splitters with different numbers of inputs and outputs can be used instead of 1×4 or 2×8, and these beam splitters can be selected to suit the application.

[0317] When the number of outputs from each beam splitter is half the number of inputs to the light-emitting element or each OPA, the outputs from two beam splitters can be alternately coupled to the input of one of the OPAs. Thus, two beam splitters supply each OPA in the light-emitting element. This alternation principle can be applied similarly to other numbers of beam splitters. For example, the light-emitting element can be supplied by three or four beam splitters. When multiple beam splitters are present, a first output from each beam splitter can be sequentially connected to the input of the light-emitting element, followed by a second output from each beam splitter, and so on, to separate the outputs from each beam splitter across the input of the light-emitting element. In other words, adjacent inputs of the light-emitting element are connected to different beam splitters.

[0318] As mentioned above, in Figure 13A In configuration B, a 1×24 optical switch is provided in the transmitter. The same switches are available for selection in the receiver, which will be discussed in more detail below. The switches can be formed from a switch tree or individual switch components. Some examples of suitable switch types will now be discussed, but the number of switches and outputs can be selected to suit the application.

[0319] Figure 17AAn example of a 1×24 optical switch formed by a 1×2 optical switch tree is shown. At each level, the output of each of the (one or more) 1×2 switches supplies the input of two 1×2 switches at another level. The levels of switches and the number of couplings can be arranged to provide the desired number of outputs.

[0320] Figure 17B An example of a 1×2 switch type is shown. The Mach-Zehnder 1×2 switch has two phase shifters and two 2×2 MMIs. Only one phase shifter is active at any given time. These switches are suitable for use in transmitter PICs. They are in Figure 17A The use of a 1×24 switch requires 23 1×2 switches, thus requiring 46 phase shifters, but at any given time a maximum of 5 phase shifters will be operating.

[0321] Another example of a 1×24 optical switch is in Figure 18A As shown in the figure, Figure 18A The diagram shows a tree consisting of 1×3 optical switches and 21 1×2 optical switches. The 1×3 optical switches form the first layer, and the remaining layers are formed by 1×2 optical switches.

[0322] An example of a 1×3 switch is in Figure 18B As shown in the diagram, the Mach-Zehnder interferometer (MZI) 1×3 switch has three phase shifters and two 3×3 MMIs. Only two phase shifters are active at any given time. These switches are suitable for use in transmitter PICs. Figure 18A The 1×24 optical switch shown requires 45 phase shifters, but at any given time a maximum of 5 phase shifters will be operating.

[0323] Figure 19 Another example of a 1×24 optical switch is shown. This switch is an OPA switch with 1 input and 24 outputs. Light travels from the input waveguide through a Gaussian beam splitter (99% Gaussian cutoff) to 28 path-length matched arm waveguides. Each arm waveguide has a phase shifter. The light then travels through a free diffraction region to the output waveguide, and the phase shift imparted to the light in the arm waveguides determines which output waveguide the light will reach. Figure 19 The diagram shows the optical path length between the arm waveguide and the output waveguides of the sixth and nineteenth outputs. All phase shifters are active between 0 and 2π. The arm waveguides are constructed similarly to arrayed waveguide grating (AWG) arms, but they are path-length matched and have phase shifters on each arm.

[0324] By changing the number of output waveguides and arm waveguides, the OPA can be designed to have different numbers of outputs.

[0325] Figure 20Another example of a 1×24 switch is shown. This example has a 1×4 Mach-Zehnder interferometer (MZI) switch and four 1×6 OPA switches. The 1×4 MZI switch has six phase shifters, but only two are operational at any given time. The 1×6 OPA switches are constructed similarly to... Figure 19 The OPA switches shown are different, but each OPA contains 6 outputs, 8 arm waveguides, and 8 phase shifters. The first layer of optical switches (1×4 in this example) can be fast switches, and the OPAs can be slow switches. In this way, the speed of the first layer of MZI switches can be utilized by allowing inactive OPA switches to switch when one of the OPAs is active.

[0326] Other possible switch arrangements are 1×3MZI switch followed by 3×8OPA switches, or 1×6MZI switch followed by 6×4OPA switches.

[0327] Figure 21 An example of a receiver PIC is shown. The receiver PIC has an optical steering component 25 with multiple input waveguides and multiple outputs, each output coupled to a coherent receiver 29 and a local oscillator (LO) source 13, providing one or more LO signals to an optical switch 22. The optical switch 22 has inputs and multiple outputs, and provides the LO signal to one of a plurality of beam splitters 23, which in turn supply the LO signal to the coherent receiver.

[0328] For the transmitter described above, other embodiments of the receiver may not have a beam splitter. In this case, the LO signal can be supplied directly to the coherent receiver from the optical switch. The input-to-output beam splitter ratio will be the same in the receiver as in the transmitter, allowing the receiver to handle all simultaneous beams generated by the transmitter.

[0329] Figure 21 The example in the diagram has a receiver optics 28 that converts the extreme components of the incident angle of the beam on the field of view (FOV) to one of the input waveguides 27. Optics 28 also guides the azimuth component of the incident angle to couple the received light into the input waveguide. The input waveguide 28 transmits the light to a layer of planar Si photonic lenses, each lens having 78 receivers. This converts the input waveguide into the input angle for the OPA used in the light steering component. The photonic lenses will be discussed in more detail below.

[0330] The light then enters the OPA of the light-directing component, which is configured to "unsteer" the light in a manner corresponding to the light-emitting component of the emitter. The light-directing component handles fine-tuning and directs the light to one of its outputs. The output of the light-directing component that the light reaches corresponds to the input of the light-emitting component at the emitter, allowing the polar components of the light's angle of incidence to be determined.

[0331] When multiple beams are emitted simultaneously by the transmitter at different polar angles, they are separated at the receiver because they are tuned to different outputs of the light steering component, each output connected to a different photodetector in the coherent receiver.

[0332] The light then reaches a coherent receiver, where the signal can be detected by beating the LO signal received from the light source of the transmitter.

[0333] In other embodiments, the LO source can be supplied from a separate source (not from the transmitter).

[0334] exist Figure 21 In the example shown, the 816 discrete polar components of the incident angle of the light at the receiver are guided by receiver optics 28 to 816 input waveguides 27. Each of these input waveguides is coupled to the input of one of twelve photonic lenses 26, each having 78 outputs. The outputs from the photonic lenses 26 are coupled to the input of a light-directing component consisting of twelve OPAs, each having 78 input waveguides and 8 output waveguides. Each output of the light-directing component is coupled to a coherent receiver, which also receives the LO signal input. When four simultaneous beams are emitted from the transmitter due to a 1×4 (or 2×8) beam splitter in the transmitter, each beam having a different polar component, only four of the eight output waveguides of the receiver OPA carry the light. Each of these four outputs is connected to a different photodetector circuit.

[0335] Examples of photonic lenses in Figure 22 As shown in the figure, the lens employs 68 input waveguides 30, with only some waveguides carrying light at any given time, and output light on 78 waveguides 31, which form the input to the OPA in the light-directing component. The lens distributes light from a single input waveguide across the 78 outputs in a 99% truncation Gaussian manner. The optical path lengths from input waveguide n1 and another input waveguide n2 are shown as an example in the figure.

[0336] The output waveguide 31 is of circular path length, and the input waveguide 30 is path length matched on the Rowland circle. The number of waveguides can be adjusted to suit the desired application and FOV.

[0337] Figure 23An example set of coherent receivers 29 is shown. Figure 21 In the example receiver, twelve of these receiver sets are provided; one for each of the twelve OPAs. The LO signal 13 is split by beam splitter 23 and then reaches the coherent receiver. As discussed above regarding the transmitter, the beam splitter can have any number of outputs to suit the application, but in this example, the beam splitter has two inputs and eight outputs. At any given time, only one input will carry light. The outputs are cross-connected to supply alternating inputs to the coherent receiver.

[0338] The coherent receiver is arranged such that the four signal inputs from the light steering component and the corresponding LO signal inputs reach the same coherent receiver and the same MMI in the coherent receiver. The beat frequency between two inputs results in a signal at the photodetector.

[0339] Each coherent receiver has a pair of multimode interference components 32 (MMIs), each MMI having one of the LO inputs and one of the signal inputs of the coherent receiver, and the outputs of both MMIs in the pair are connected to one or more common photodetectors 33. Due to the alternating arrangement of the beam splitters, the two LO inputs in the pair are each coupled to different outputs of the optical switches. Therefore, only one of the MMIs in the pair will be active at any given time. This arrangement allows for greater use of the coherent receivers and reduces the number of components required. The output of the photodetector is routed to a transimpedance amplifier (TIA) to amplify the signal. If the photodetector is connected to more than one MMI, the system can be configured such that only one MMI carries light from the LO at any given time. Furthermore, if an MMI carries LO light, the corresponding signal input of the MMI carries the signal from the received beam.

[0340] Figure 21 The OPA layer in the receiver is structurally similar to that of... Figure 14 The OPAs described are the same, but used in reverse. Figure 21 The switches and splitters in the receiver are also structurally similar to those regarding... Figures 16A to 20 The descriptions are the same.

[0341] The light source in the emitter can be provided by one or more lasers 134. An example of the arrangement of lasers 134 is shown in... Figures 24 to 29 As shown in the diagram. As mentioned above, different wavelengths can be provided so that the azimuth component of the FOV can be sampled via wavelength-dependent steering. Figure 24 In the example, four separate lasers are provided, allowing four wavelengths of light to be provided simultaneously. The four lasers 134 provide a total of 32 different coarse wavelengths. Each laser can be tuned between eight different wavelengths covering a subrange of the total 32 wavelengths.

[0342] Each of the lasers 134 has a separate output between a light source for the transmitter and an LO source for the receiver.

[0343] After the light is separated between the LO source and the light source, the light from all the lasers is multiplexed by a band multiplexer (MUX) 135 so that it is carried by a single waveguide acting as the light source. The light from the LO source is also multiplexed by a band multiplexer 136 so that it is carried by a single waveguide acting as the LO source.

[0344] The light from each laser 134 is phase-modulated by a phase modulator (PM). The modulation can be configured to allow distance determination (e.g., by pulse detection for time-of-flight systems or frequency chirping for FMCW systems). Furthermore, the light can be encoded to indicate the origin of the light in the transmitter. The receiver can then decode the azimuth. Modulation can be applied to the light (e.g.,...) Figure 25 (As shown) This occurs before or after the separation between the LO source and the light source, such as Figure 24 As shown. The LO source may not be modulated at all, such as... Figure 25 As shown. Alternatively, modulation can occur within the laser itself, such as... Figure 26 As shown, it realizes a tunable FM modulated laser.

[0345] Before or after multiplexing light from each laser, the light can also be amplified by utilizing semiconductor optical amplifiers. Figures 24 to 26 The SOA shown is an example of a possible location for an SOA.

[0346] The light from the LO signal can be attenuated by a variable optical attenuator (VOA) to reduce LO power and / or improve the signal-to-noise ratio performance of the received light.

[0347] Figure 27 A set of lasers G1-G4 is shown in the light source suitable for the transmitter PIC, for example, according to Figures 24 to 26 It is arranged in one of the following configurations. It consists of 32 distributed Bragg reflector (DBR) lasers, covering a total wavelength range of 100 nm. Each laser can be tuned in increments of approximately 3 nm, in increments of 0.11 nm. The lasers are grouped into four groups of eight lasers each, and all lasers in a group output to a set of waveguides. Four different wavelengths can be provided simultaneously within this waveguide.

[0348] The multiplexer can be an AWG or an echelle grating or a cascaded MZI MUX, which has thermal matching to match the input.

[0349] Figure 28An example of a tunable laser is shown. The laser is an eight-channel tunable CW laser. A reflective semiconductor optical amplifier (RSOA) receives eight different laser gain currents I0. LD1 to I LD8 It is designed for fine-tuning of power and wavelength and features a single EPI with a gain of approximately 30 nm. It also has a high-reflectivity coating on the rear surface facing away from the imaging environment and an anti-reflective coating on the front (output) surface.

[0350] Silicon gratings λ1 to λ8 have a receiving current I HT1 to I HT8 The heater is used for temperature tuning up to 3.6 nm over a 50°C temperature change. The silicon grating has eight different time periods. The channels are then multiplexed by an 8×1 multiplexer. Only one laser element operates at any given time, and a monitoring tap can also be provided after the multiplexer.

[0351] Figure 29 Another laser that can be implemented is shown. It is similar to the one mentioned above. Figure 28 The described structure, except for the laser RF current I RF1 to I RF8 It is also input for FM chirping.

[0352] Figure 34 An example of a laser and a MUX is shown, where two eight-channel lasers supply a 1×16 multiplexer (MUX). A wavelength monitor supplied by a portion of the MUX's output is also provided. The wavelength monitor can be off-chip. The wavelength control of the lasers can also be off-chip. The amplitude and wavelength of the lasers are adjustable. The MUX has a balanced envelope response, which can help flatten the optical power output with wavelength. The 16 lasers can cover a 50nm wavelength range because each laser has a 4nm tuning range.

[0353] Figure 30 An optical device is shown that can be used to convert the output of the light-emitting component of a transmitter PIC to cover the FOV of the transmitter. Figure 13A Each OPA of the light-emitting component of B can generate a polar angle component within a range of + / -45 degrees. Figure 30 The optics in the design have two layers. The first layer transforms the field of view (FOV) of each OPA from + / -45 degrees to a smaller FOV of + / -3.75 degrees. This first layer can be an array of 12 microlenses. The second optics layer adds an incremental steering to each output, such that the entire light-emitting component covers the entire range of the FOV. In this example, the steering is (7.5n - 3.75) degrees, where n is an integer between -5 and 6.

[0354] Figure 31An example of a transmitter is shown, wherein the azimuth component of the field of view is divided into three segments, each segment being scanned using a corresponding OPA, OPA1-3. In other embodiments, a different number of light-emitting elements may be provided, such that the azimuth FOV can be divided into two or more segments. A beam splitter 55 is disposed between the light source 41 and the light-emitting elements (OPAs in this example, but other types of light-emitting elements may be present in other examples). Each light-emitting element is configured to guide light at its corresponding portion of the azimuth. The beam splitter is configured to separate the light received at the input between the plurality of outputs. Each light-emitting element has a plurality of inputs and a plurality of emitters, the light-emitting element including at least one OPA. Each light-emitting element is configured to selectively emit a beam at a plurality of emission angles having different corresponding polar components within the polar angular range of the FOV, and wherein the light-emitting element and said or each additional light-emitting element are configured to selectively emit a beam each at different corresponding ranges of the azimuth component. The input to the beam splitter is coupled to the light source, and each of the outputs of the beam splitter is coupled to the input of a corresponding one of the light-emitting elements. In this example, the OPA consists of blocks of phase shifters and grating emitters. Phase tuning is used to guide the azimuth component of the light, and the polar component of the light is divided into three segments for wavelength tuning. This example uses 32 lasers with 3nm tuning, and each segment covers 15 degrees of the polar FOV. The grating emitter in each of the three light-emitting components is configured to guide the light to its corresponding segment of the polar component of the FOV.

[0355] Figure 33 An example arrangement of a PIC transceiver, wedge, plate, and optics is shown. As shown in the side view, the optics can be positioned on the front (top) of the wedge, and the wedge and plate can be positioned on the PIC such that the transmitter light-emitting component is aligned with the wedge, and the light-collecting component on the PIC is behind the rear of the plate. A 45-degree directional mirror can be provided at the end of the plate to guide light away from the plate to one or more receiver light-collecting components.

[0356] It is conceivable that any of the embodiments described herein may be adapted to include a liquid crystal phase shifter. Figure 35 An example of such a LiDAR system incorporating a liquid crystal phase shifter according to the present invention is shown. The illustrated embodiment is a 32-beam LiDAR with a first group of 16 beams and a second group of 16 beams, with only one group of beams active at any given time. However, it should be noted that the same setup can be applied to any integer number x of beams, where x / 2 beams are active at a time.

[0357] Two types of scans occur. A first scan step provides scanning in a first dimension, and a second scan step provides scanning in a second dimension. The first scan step is a "fast scan" process with a faster scanning speed relative to the second "slow scan" step. The first scan step, occurring in the first dimension, is performed using laser tuning and refractive optics. The refractive optics can take the form of plates, wedges, and lenses. The second scan step, occurring in the second dimension, uses liquid crystals. In the illustrated embodiment, a first group of 16 lasers performs a rapid scan in the first dimension, while the liquid crystals of a second group of 16 lasers are reset to a new angle. Once the liquid crystals are set at the second angle, the system switches from the first group of lasers to the second group, which then performs a rapid scan using their respective refractive optics.

[0358] Each laser can be in the form of a DFB laser, which is tunable within a given wavelength range; an example of a suitable wavelength range is 2.5 μm.

[0359] Two sets of lasers can be located on a single photonic integrated circuit (PIC). The light output from the PIC passes through expansion and collimation optics, followed by refractive optics that control scanning in the first dimension, and finally through a liquid crystal that controls scanning in the second dimension. The aperture after the liquid crystal can have a diameter of 1, 2, 3, 4, or 5 mm.

[0360] Importantly, such as Figure 35 As shown, the entire system can be configured to operate in both transmit (tx) and receiver (rx) modes.

[0361] An example arrangement can be formed using gratings and wavelengths on the emitter to efficiently sample the field of view (FOV) using waveguides with a height of 1 μm or less, and this can be combined into a 1D ensemble of gratings across the OPA waveguides. However, small waveguides (e.g., 1 μm or less) may be more sensitive to OPA phase error manufacturing tolerances, and complex gratings (e.g., blazed profiles or phase plates) are more process-intensive and take longer to integrate into the fabrication of silicon photonics processes. Using external gratings (e.g., glass) or phase plate elements can provide more degrees of freedom and simplify overall manufacturing. The configuration of the gratings and lenses can be selected to suit the application.

[0362] The features disclosed in the foregoing description, or in the following claims, or in the drawings (expressed in their specific form or according to means for performing the disclosed function, or methods or processes for obtaining the disclosed result) (as the case may be) may be used alone or in any combination of these features to implement the invention in its various forms.

[0363] Any LiDAR system described herein can be applied to larger automotive systems, including one or more vehicles or one or more components for use on vehicles.

[0364] While the invention has been described in conjunction with the exemplary embodiments described above, many equivalent modifications and variations will be apparent to those skilled in the art upon presentation of this disclosure. Therefore, the exemplary embodiments of the invention described above are to be considered illustrative rather than restrictive. Various changes may be made to the described embodiments without departing from the spirit and scope of the invention.

[0365] To avoid any doubt, any theoretical explanations provided herein are for the purpose of enhancing the reader's understanding. The inventor does not wish to be bound by any of these theoretical explanations.

[0366] Any chapter headings used in this document are for organizational purposes only and should not be construed as limiting the subject matter described.

[0367] Throughout this specification, including the following claims, unless the context otherwise requires, the words “comprising” and “including”, as well as variations of “comprising,” “including,” and “including,” shall be understood to imply inclusion of the said whole or step or group of whole or steps, but not to exclude any other whole or step or group of whole or steps.

[0368] It should be noted that, as used in the specification and appended claims, the singular forms “a,” “an,” and “the” include plural indicators unless the context clearly specifies otherwise. A range may be expressed herein as from “about” a particular value and / or to “about” another particular value. When such a range is expressed, another embodiment includes from one particular value and / or to another particular value. Similarly, when a value is expressed as an approximation using the antecedent “about,” it should be understood that the particular value forms another embodiment. The term “about” with respect to numerical values ​​is optional and means, for example, + / - 10%.

Claims

1. A LiDAR emitter photonic integrated circuit (PIC) for scanning the environment over a field of view (FOV), the FOV having an azimuth range and a polar range, the LiDAR emitter PIC being configured to scan the azimuth range using wavelength scanning and to scan the polar range using at least one optical phased array (OPA), the LiDAR emitter PIC comprising: A light source for providing light from at least one laser, wherein the light source comprises a plurality of lasers, each laser being configured to produce light of a corresponding different wavelength within a wavelength range. An optical switch having an input and multiple outputs, the optical switch being configured to selectively direct light received at the input to one of the multiple outputs, and A light-emitting component having multiple inputs and multiple emitters, the light-emitting component being configured to selectively emit beams at multiple emission angles having different corresponding polar components within the polar angle range of the field of view (FOV), and wherein the emitters are grating emitters configured to tune light having wavelengths within the wavelength range to corresponding azimuth components, wherein the light-emitting component includes at least one optical emission platform (OPA), the OPA or each OPA being configured to selectively emit beams at one or more of the multiple emission angles. The light source is coupled to the input of the optical switch, and each of the plurality of outputs of the optical switch is coupled to a corresponding one of the plurality of inputs of the light-emitting element. The light source is a tunable emitter configured to simultaneously provide multiple wavelengths. The LiDAR transmitter PIC further includes multiple beam splitters, each having an input and multiple outputs, and configured to separate the light received at the input among the multiple outputs. Each output of the optical switch is coupled to a corresponding input of the beam splitter, and each output of the beam splitter is coupled to a corresponding input of the light-emitting element. The outputs of more than one of the plurality of beam splitters are alternately coupled to the input of the OPA or one of the OPAs, such that no two adjacent inputs of the OPA are coupled to the same output of the optical switch. The LiDAR transmitter PIC is configured to simultaneously generate multiple corresponding different wavelengths of light within the wavelength range, and the grating emitter is configured to split the light into corresponding azimuth angles. The optical switch and the light-emitting component form a switching matrix, which is configured to select the extreme components of the emission angle of the light. The optical switch is a fast switching element, the light-emitting component is a slow switching element, and the switching time of the entire switching matrix is ​​the switching time of the optical switch.

2. The LiDAR emitter PIC of claim 1, wherein the light-emitting element comprises a plurality of OPAs, and each of the plurality of inputs of the light-emitting element comprises an input to one of the plurality of OPAs, and each of the plurality of emitters of the light-emitting element comprises an output of one of the plurality of OPAs.

3. The LiDAR transmitter PIC according to claim 2, wherein each OPA has an equal number of transmitters.

4. The LiDAR transmitter PIC of claim 1, wherein the OPA or each OPA has more than one input.

5. The LiDAR transmitter PIC of claim 1, wherein the number of outputs from each beam splitter is half the number of inputs to the OPA or each OPA, and the outputs from the two beam splitters are alternately coupled to the input of one of the OPAs.

6. The LiDAR transmitter PIC of claim 1, wherein the LiDAR transmitter PIC is configured to emit multiple beams simultaneously.

7. The LiDAR transmitter PIC of claim 1, wherein the OPA or each OPA of the light-emitting component further comprises an arm waveguide array and one or more phase shifters configured to shift the phase of light in the arm waveguides, the applied phase shift amount depending on the arm waveguides in which the light travels.

8. The LiDAR transmitter PIC of claim 7, wherein the phase shift varies linearly across the array of the arm waveguides.

9. The LiDAR transmitter PIC of claim 7, wherein the one or more phase shifters are heaters configured to apply heat to a corresponding length of each corresponding arm waveguide in the array, the corresponding length varying across the array of arm waveguides.

10. The LiDAR transmitter PIC of claim 9, wherein the corresponding length varies linearly across the array of the arm waveguides.

11. The LiDAR transmitter PIC of claim 10, wherein each of the one or more heaters has a triangular or rounded triangular shape.

12. The LiDAR transmitter PIC of claim 1, wherein the light source further comprises a plurality of modulators, each modulator being configured to modulate light from a corresponding laser among the plurality of lasers.

13. The LiDAR transmitter PIC of claim 1, wherein the laser or each laser is tunable over a corresponding wavelength subrange within the wavelength range.

14. The LiDAR transmitter PIC of claim 1, wherein the transmitter PIC further comprises: A second beam splitter has an input and multiple outputs, and is configured to separate the light received at the input among the multiple outputs. One or more additional light-emitting components, each of which has multiple inputs and multiple emitters, including at least one OPA, configured to selectively emit a beam at multiple emission angles having different corresponding polar components within the polar angle range of the FOV, and wherein the light-emitting component and the additional light-emitting components are each configured to selectively emit a beam at different corresponding ranges of azimuth components. The input to the second beam splitter is coupled to the light source, and a first output of the output of the second beam splitter is coupled to the input of the light-emitting element, and other outputs of the second beam splitter, or each other output, are coupled to the input of a corresponding additional light-emitting element.

15. A LiDAR emitting component, comprising: The LiDAR transmitter PIC according to claim 2, A first optical element is configured to convert light emitted from each OPA to a second polar angle range, the second polar angle range being smaller than the polar angle range of the FOV. The second optical device is configured to adjust the corresponding polar steering angle of the light from each OPA.

16. The LiDAR emitting component according to claim 15, further comprising: An air-to-air grating, configured to create multiple emitted beams of each wavelength, each of which is separate, and / or An angular magnifying optics device used to increase the azimuth component of the emission angle.

17. A LiDAR emitting component, comprising: The LiDAR transmitter PIC according to claim 1, and An air-to-air grating is configured to create multiple emitted beams of each wavelength, each of which is separate, and / or angular magnifying optics are used to amplify the azimuth component of the emission angle.

18. A LiDAR receiver PIC for receiving reflected light from the environment in a LiDAR system, said LiDAR system comprising a LiDAR transmitter PIC according to claim 1, and said LiDAR receiver PIC comprising: The optical steering component has multiple input waveguides and multiple outputs. The local oscillator LO source provides one or more LO signals. An optical switch having an input and multiple outputs, the optical switch being configured to selectively direct light received at the input to one of the multiple outputs, and Multiple coherent receivers, each having a signal input and a LO input, and at least one photodetector. The LO source is coupled to the input of the optical switch, and each of the outputs of the optical switch is coupled to a corresponding LO input. Each of the outputs of the light steering component is coupled to a corresponding one of the signal inputs. The optical steering component includes a plurality of OPAs, and each of the plurality of input waveguides of the optical steering component includes an input to one of the plurality of OPAs, and each of the plurality of outputs of the optical steering component includes an output to one of the plurality of OPAs. The LO source is configured to provide multiple wavelengths simultaneously. The LiDAR receiver PIC further includes multiple beam splitters, each having an input and multiple outputs, and configured to separate the light received at the input among the multiple outputs. Each of the outputs of the optical switches is coupled to a corresponding input of one of the beam splitters, and each of the outputs of each of the beam splitters is coupled to a corresponding LO input of one of the coherent receivers.

19. The LiDAR receiver PIC of claim 18, wherein the OPA or each OPA has more than one output.

20. The LiDAR receiver PIC of claim 18, wherein each OPA has an equal number of inputs.

21. The LiDAR receiver PIC of claim 18, wherein the input waveguides are spaced between 1 and 2 μm, or the input waveguides are spaced 1.1 μm apart.

22. The LiDAR receiver PIC of claim 18, wherein each coherent receiver includes a pair of multimode interferometers (MMIs), each MMI having one of the LO inputs and one of the signal inputs of the coherent receiver, and both MMIs in the pair output to one or more common photodetectors, wherein the two LO inputs in the pair are each coupled to different outputs of the optical switch.

23. The LiDAR receiver PIC of claim 18, wherein the OPA or each OPA of the light steering component further comprises an arm waveguide array and one or more phase shifters configured to shift the phase of light in the arm waveguides, the applied phase shift amount depending on the arm waveguides in which the light travels.

24. The LiDAR receiver PIC of claim 23, wherein the phase shift varies linearly across the arm waveguide array.

25. The LiDAR receiver PIC of claim 23, wherein the one or more phase shifters are heaters configured to apply heat to a corresponding length of each corresponding arm waveguide in the array, the corresponding length varying across the arm waveguide array.

26. The LiDAR receiver PIC of claim 25, wherein the corresponding length varies linearly.

27. The LiDAR receiver PIC of claim 26, wherein each of the one or more heaters has a triangular or rounded triangular shape.

28. A LiDAR transceiver for scanning the environment over a field of view (FOV), the FOV having an azimuth range and a polar range, the LiDAR transceiver comprising: A LiDAR transmitter photonic integrated circuit (PIC), the LiDAR transmitter PIC being configured to scan the azimuth range using wavelength scanning and the polar range using at least one optical phased array (OPA), and comprising: A light source for providing light from at least one laser, wherein the light source comprises a plurality of lasers, each laser being configured to produce light of a corresponding different wavelength within a wavelength range. A transmitter optical switch having an input and multiple outputs, the optical switch being configured to selectively direct light received at the input to one of the multiple outputs, and A light-emitting component having multiple inputs and multiple emitters, the light-emitting component being configured to selectively emit beams at multiple emission angles having different corresponding polar components within the polar angle range of the field of view (FOV), wherein the emitters are grating emitters configured to tune light having wavelengths within the wavelength range to corresponding azimuth components, wherein the light-emitting component includes at least one optical emission platform (OPA), the OPA or each OPA being configured to selectively emit beams at one or more of the multiple emission angles. The light source is coupled to the input of the emitter optical switch, and each of the plurality of outputs of the emitter optical switch is coupled to a corresponding one of the plurality of inputs of the light-emitting element; and LiDAR receiver PIC includes: The optical steering component has multiple input waveguides and multiple outputs. The local oscillator LO source provides one or more LO signals. A receiver optical switch having an input and multiple outputs, the optical switch being configured to selectively direct light received at the input to one of the multiple outputs, and Multiple coherent receivers, each having a signal input and a LO input, and at least one photodetector. The LO source is coupled to the input of the receiver optical switch, and each of the outputs of the receiver optical switch is coupled to a corresponding LO input. Each of the outputs of the light steering component is coupled to a corresponding one of the signal inputs. The light source is a tunable emitter configured to simultaneously provide multiple wavelengths. The LiDAR transmitter PIC also includes multiple beam splitters, each with an input and multiple outputs, and is configured to separate the light received at the input among the multiple outputs. Each output of the emitter optical switch is coupled to a corresponding input of the beam splitter, and each output of each beam splitter is coupled to a corresponding input of the light-emitting element. The outputs of more than one of the plurality of beam splitters are alternately coupled to the input of the OPA or one of the OPAs, such that no two adjacent inputs of the OPA are coupled to the same output of the optical switch. The LiDAR transmitter PIC is configured to simultaneously generate multiple corresponding different wavelengths of light within the wavelength range, and the grating emitter is configured to split the light into corresponding azimuth angles. The optical switch and the light-emitting component form a switching matrix, which is configured to select the extreme components of the emission angle of the light. The optical switch is a fast switching element, the light-emitting component is a slow switching element, and the switching time of the entire switching matrix is ​​the switching time of the optical switch.

29. The LiDAR transceiver of claim 28, wherein the LiDAR transmitter PIC is disposed on the first photonic chip.

30. The LiDAR transceiver of claim 28, wherein the LiDAR receiver PIC is disposed on the second photonic chip.

31. The LiDAR transceiver of claim 29, wherein the LiDAR transmitter PIC and the LiDAR receiver PIC are disposed on the same monolithic photonic chip.

32. The LiDAR transceiver of claim 28, wherein the LO source is supplied by the light source.

33. The LiDAR transceiver of claim 28, wherein the LO source is modulated or unmodulated.

34. The LiDAR transceiver according to claim 32, The transceiver is configured such that the signal input and the LO input to each coherent receiver carry light of the same wavelength within the wavelength range.

35. The LiDAR transceiver of claim 34, wherein the light source is configured to encode the light such that each corresponding wavelength of light has a different corresponding code.

36. The LiDAR transceiver of claim 35, wherein each corresponding code is chirped or amplitude modulated.

37. The LiDAR transceiver according to claim 28, further comprising: A first optical element is configured to convert light emitted from each OPA to a second polar angle range, the second polar angle range being smaller than the polar angle range of the FOV. The second optical device is configured to adjust the corresponding polar steering angle of the light from each OPA.

38. The LiDAR transceiver of claim 37, wherein the polar steering angle is ±ny, where n is an integer and y is the size of the range of the second polar angle.

39. The LiDAR transceiver of claim 37, wherein the polar angle range of the FOV is ±45 degrees, and / or the second polar angle range is ±3.75 degrees.

40. A LiDAR emitter photonic integrated circuit (PIC) for scanning the environment on a field of view (FOV), the FOV having an azimuth range and a polar range, the LiDAR emitter PIC being configured to scan the azimuth range using wavelength scanning and to scan the polar range using at least one optical phased array (OPA), and comprising: The light source includes multiple lasers, each configured to produce light of a corresponding different wavelength within a wavelength range. An optical switch having an input and multiple outputs, the optical switch being configured to selectively direct light received at the input to one of the multiple outputs, and A light-emitting component having multiple inputs and multiple emitters, the light-emitting component being configured to selectively emit beams at multiple emission angles having different corresponding polar components within the polar angle range of the field of view (FOV), wherein the emitters are grating emitters configured to tune light having wavelengths within the wavelength range to corresponding azimuth components, wherein the light-emitting component includes at least one optical emission platform (OPA), the OPA or each OPA being configured to selectively emit beams at one or more of the multiple emission angles. The light source is coupled to the input of the optical switch, and each of the plurality of outputs of the optical switch is coupled to a corresponding one of the plurality of inputs of the light-emitting element, such that the optical switch and the light-emitting element form a switching matrix, and the switching matrix is ​​configured to select the polar component of the emission angle of light, the polar component being within the polar angle range. The light source is a tunable emitter configured to simultaneously provide multiple wavelengths. The LiDAR transmitter PIC further includes multiple beam splitters, each having an input and multiple outputs, and configured to separate the light received at the input among the multiple outputs. Each output of the optical switch is coupled to a corresponding input of the beam splitter, and each output of the beam splitter is coupled to a corresponding input of the light-emitting element. The outputs of more than one of the plurality of beam splitters are alternately coupled to the input of the OPA or one of the OPAs, such that no two adjacent inputs of the OPA are coupled to the same output of the optical switch. The LiDAR transmitter PIC is configured to simultaneously generate multiple corresponding different wavelengths of light within the wavelength range, and the grating emitter is configured to split the light into corresponding azimuth angles. The optical switch is a fast switching element, the light-emitting component is a slow switching element, and the switching time of the entire switching matrix is ​​the switching time of the optical switch.

41. The LiDAR transmitter PIC of claim 40, wherein the optical switch is a faster switch than the light-emitting component.

42. The LiDAR transmitter PIC of claim 40, wherein the optical switch is a slower switch than the light-emitting component.

43. The LiDAR transmitter PIC of claim 40, wherein the transmitter is configured to scan an array of emission angles and emit light to each of the emission angles at a pixel time t. pixel Furthermore, the optical switch is capable of switching at time t switch Switching between outputs, and t pixel > t switch .

44. The LiDAR transmitter PIC of claim 40, wherein the transmitter is configured to scan an array of emission angles and emit light to each of the emission angles at a pixel time t. pixel Furthermore, the optical switch is capable of switching at time t switch Switching between outputs, and t pixel < t switch .

45. The LiDAR transmitter PIC of claim 40, wherein the transmitter is configured to scan an array of emission angles and emit light to each of the emission angles at a pixel time t. pixel Furthermore, the light-emitting component is capable of switching at time t lec The middle switches between extreme components, and t pixel > t lec .

46. ​​The LiDAR transmitter PIC of claim 40, wherein the transmitter is configured to scan an array of emission angles and emit light to each of the emission angles at a pixel time t. pixel Furthermore, the light-emitting component is capable of switching at time t lec The middle switches between extreme components, and t pixel < t lec .

47. The LiDAR transmitter PIC of claim 40, wherein the light-emitting element is configured such that each input of the light-emitting element corresponds to a corresponding subrange of the polar angle range, such that the input determines a subrange of the polar angle from which light can be emitted from the light-emitting element, the light reaching the light-emitting element at the input.

48. The LiDAR transmitter PIC of claim 40, wherein the light-emitting element comprises a plurality of sub-light-emitting elements, each sub-light-emitting element having one or more of the plurality of inputs of the light-emitting element, and each sub-light-emitting element corresponding to a corresponding sub-range of the polar angle range, such that the sub-light-emitting element to which light reaches determines a sub-range of the polar angle from which light can be emitted.

49. The LiDAR transmitter PIC of claim 48, wherein the optical switch is configured to sequentially direct light to sub-emitting elements such that each sub-emitting element receives light for a corresponding time t. on Then, the light does not arrive for the corresponding time t. off For each sub-light-emitting component, t off ≥t lec .

50. The LiDAR emitter PIC of claim 48, wherein each sub-emitting element is configured such that each input of the sub-emitting element corresponds to a corresponding sub-range of the polar angle range, such that the input determines a sub-range of the polar angle from which light can be emitted, the light reaching the sub-emitting element at the input.

51. The LiDAR emitter PIC of claim 48, wherein each sub-emitting element is an OPA.

52. The LiDAR transmitter PIC of claim 40, wherein the optical switch is a fast switch and the light-emitting component is a slow switching element.

53. The LiDAR emitter PIC of claim 52, wherein the light-emitting component comprises one or more heaters.

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