WO2024040281A1 - Directeur de faisceau optique - Google Patents

Directeur de faisceau optique Download PDF

Info

Publication number
WO2024040281A1
WO2024040281A1 PCT/AU2023/050789 AU2023050789W WO2024040281A1 WO 2024040281 A1 WO2024040281 A1 WO 2024040281A1 AU 2023050789 W AU2023050789 W AU 2023050789W WO 2024040281 A1 WO2024040281 A1 WO 2024040281A1
Authority
WO
WIPO (PCT)
Prior art keywords
light
outgoing light
outgoing
beam director
incoming
Prior art date
Application number
PCT/AU2023/050789
Other languages
English (en)
Inventor
Fernando Diaz
Cibby Pulikkaseril
Original Assignee
Baraja Pty Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from AU2022902394A external-priority patent/AU2022902394A0/en
Application filed by Baraja Pty Ltd filed Critical Baraja Pty Ltd
Publication of WO2024040281A1 publication Critical patent/WO2024040281A1/fr

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/88—Lidar systems specially adapted for specific applications
    • G01S17/89—Lidar systems specially adapted for specific applications for mapping or imaging
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/04—Systems determining the presence of a target
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S17/00—Systems using the reflection or reradiation of electromagnetic waves other than radio waves, e.g. lidar systems
    • G01S17/02—Systems using the reflection of electromagnetic waves other than radio waves
    • G01S17/06—Systems determining position data of a target
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • G01S7/4817—Constructional features, e.g. arrangements of optical elements relating to scanning
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01S—RADIO DIRECTION-FINDING; RADIO NAVIGATION; DETERMINING DISTANCE OR VELOCITY BY USE OF RADIO WAVES; LOCATING OR PRESENCE-DETECTING BY USE OF THE REFLECTION OR RERADIATION OF RADIO WAVES; ANALOGOUS ARRANGEMENTS USING OTHER WAVES
    • G01S7/00—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00
    • G01S7/48—Details of systems according to groups G01S13/00, G01S15/00, G01S17/00 of systems according to group G01S17/00
    • G01S7/481—Constructional features, e.g. arrangements of optical elements
    • G01S7/4818—Constructional features, e.g. arrangements of optical elements using optical fibres
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/12007—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer
    • G02B6/12009—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer comprising arrayed waveguide grating [AWG] devices, i.e. with a phased array of waveguides
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
    • G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
    • G02B6/122—Basic optical elements, e.g. light-guiding paths
    • G02B6/1228—Tapered waveguides, e.g. integrated spot-size transformers
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/28—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals
    • G02B6/293—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means
    • G02B6/29379—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device
    • G02B6/2938—Optical coupling means having data bus means, i.e. plural waveguides interconnected and providing an inherently bidirectional system by mixing and splitting signals with wavelength selective means characterised by the function or use of the complete device for multiplexing or demultiplexing, i.e. combining or separating wavelengths, e.g. 1xN, NxM
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
    • G02B6/24—Coupling light guides
    • G02B6/26—Optical coupling means
    • G02B6/32—Optical coupling means having lens focusing means positioned between opposed fibre ends
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
    • H04B10/11—Arrangements specific to free-space transmission, i.e. transmission through air or vacuum
    • H04B10/114—Indoor or close-range type systems
    • H04B10/116—Visible light communication

Definitions

  • the present invention relates to components, systems and methods for directing light into multiple directions. More particularly, embodiments of the present disclosure relate to a beam director for a spatial profiling system.
  • the present invention generally relates to systems and methods for light-based estimation of a terrestrial or extra-terrestrial environment, for example to LiDAR systems and methods performed by LiDAR systems. Certain embodiments relate to a beam director suitable for use in such systems and to methods of light beam direction.
  • Spatial profiling refers to the two-dimensional (2D) or three-dimensional (3D) mapping of an environment over a 2D or 3D field of view of the environment. Each point or pixel in the field of view is associated with a distance to form a 2D or 3D representation of the environment. Spatial profiles may be useful in identifying objects and/or obstacles in the environment, thereby facilitating automation of tasks.
  • One technique of spatial profiling involves sending light into an environment in a specific direction and detecting any light reflected back from that direction, for example, by a reflecting surface in the environment.
  • This technique may be referred to as light detection and ranging, or LiDAR.
  • the reflected light carries relevant information for determining the distance to the reflecting surface.
  • the combination of the specific direction and the distance forms a point or pixel in the three-dimensional representation of the environment.
  • the above steps may be repeated for multiple different directions to form other points or pixels of the three-dimensional representation, thereby estimating the spatial profile of the environment within a desired field of view.
  • the present disclosure generally relates to spatial profiling systems, and to components for use in spatial profiling systems and to methods for spatial profiling.
  • a spatial estimation formed by the spatial profiling system may be of a terrestrial or an extra-terrestrial environment.
  • Various embodiments are described that include a beam director and a bidirectional optical subsystem, for example an optical circulator, downstream of the beam director, in an outgoing light path.
  • the beam director and bidirectional optical subsystem or optical circulator are integrated components, for example integrated onto a common substrate.
  • optical components for beam direction may include one or more dispersion components.
  • the dispersion components have an input slab and an array of waveguides optically coupled to the input slab.
  • the input slab diffracts the outgoing light, like in an arrayed waveguide grating, and the array of waveguides have ends across the diffracted outgoing light.
  • the dispersion components may further have or may lack an output slab.
  • the or a spatial profiling system includes a beam director configured to receive, directly or indirectly, outgoing light generated by a light source and direct the outgoing light based on wavelength, wherein the outgoing light is received at a first port of the beam director and a bidirectional optical subsystem configured to receive, directly or indirectly, the directed outgoing light for sending to the environment.
  • the bidirectional optical subsystem is further configured to send, directly or indirectly, incoming light including outgoing light reflected by the environment, to a second port of the beam director, wherein the second port is spatially offset from the first port of the beam director.
  • the beam director is further configured to send, directly or indirectly, the incoming light to a light receiver.
  • the spatial offset is larger than a beam diameter of the outgoing light.
  • At least one of the beam director, bidirectional optical subsystem and light conditioning element is fabricated on an integrated circuit chip.
  • At least two of the beam director, bidirectional optical subsystem and light conditioning element are integrated components. In some embodiments the beam director, bidirectional optical subsystem and light conditioning element are all integrated components.
  • the beam director includes at least one integrated circuit chip arrayed waveguide grating (AWG) type component, including a first AWG type component including: an input slab configured to receive the outgoing light and diffract the outgoing light; and an array of waveguides of different path lengths configured to receive the outgoing light from the input slab.
  • AWG integrated circuit chip arrayed waveguide grating
  • the bidirectional optical subsystem is paired with the first AWG type component and configured to receive, directly or indirectly, the outgoing light from the first AWG type component.
  • the array of waveguides is further configured to receive the incoming light.
  • the input slab is further configured to receive the incoming light directly from the array of waveguides and send, directly or indirectly, the incoming light to the light receiver.
  • the first AWG type component further includes an output slab configured to receive the outgoing light from the array of waveguides and output outgoing light, wherein the output slab is further configured to send the incoming light to the array of waveguides.
  • the first AWG type component does not include an output slab and wherein: the bidirectional optical subsystem is configured to receive the outgoing light from the array of waveguides and output the incoming light to the array of waveguides; and the input slab is further configured to receive the incoming light from the array of waveguides.
  • the spatial profiling system further includes at least one light conditioning element, for example a collimator, downstream of the optical circulator.
  • the beam director is a first beam director configured to direct the outgoing light over a first dimension of the environment and wherein the spatial profiling system further includes a second beam director configured to direct the outgoing light over a second dimension, wherein the second dimension is or includes a component perpendicular to the first dimension.
  • the second beam director may be, but is not necessarily, a mechanical beam director.
  • Embodiments of a sensor head for directing light into an environment for spatial profiling are also described, the sensor head providing an outgoing light path to an environment for light from a light source and providing an incoming light path for light from the environment, the incoming light path including the beam director and the bidirectional optical subsystem.
  • the outgoing light path includes a beam director including dispersion components configured to direct the outgoing light based on its wavelength and a bidirectional optical subsystem configured to receive, directly or indirectly, the outgoing light from the at least one beam director and output the outgoing light.
  • At least one of the beam director and bidirectional optical subsystem is fabricated on an integrated circuit chip. In some embodiments the beam director and the bidirectional optical subsystem are integrated components.
  • the outgoing light path further includes a beam-shaping component, wherein the beam-shaping component is a further said integrated component.
  • the outgoing light path is a first outgoing light path and the beam director is a first beam director and wherein the sensor head includes a second outgoing light path, the second outgoing light path including a second beam director, different from the first beam director.
  • bidirectional optical subsystem which may include or consist of an optical circulator, is common between the first outgoing light path and the second outgoing light path.
  • the beam director is configured to direct the outgoing light over a first dimension of the environment and wherein the spatial profiling system further includes a second beam director configured to direct the outgoing light over a second dimension, wherein the second dimension is or includes a component perpendicular to the first dimension.
  • Embodiments of a method performed in or by a spatial profiling system include directing outgoing light to an environment over an outgoing light path including a beam director that directs light based on wavelength of the outgoing light and a bidirectional optical subsystem downstream of the beam director, and receiving incoming light from the environment including outgoing light reflected by the environment over an incoming light path including the bidirectional optical subsystem and the beam director, wherein bidirectional optical subsystem spatially separates the incoming light path from the outgoing light path.
  • a spatial profiling system for profiling an environment
  • the spatial profiling system including an outgoing light path for outgoing light to the environment and an incoming light path for incoming light from the environment, and a beam director configured to direct in one or more of multiple directions: (a) the outgoing light travelling through the beam director along a first portion of the outgoing light path; and (b) incoming light travelling through the beam director along a first portion of the incoming light path.
  • the first portion of the outgoing light path is at least partially non-coaxial with the first portion of the incoming light path.
  • the system also includes a bidirectional optical subsystem configured to cause: (a) the directed outgoing light to travel through the bidirectional optical subsystem along a second portion of the outgoing light path, different to the first portion of the outgoing light path, and (b) the incoming light to travel through the bidirectional optical subsystem along a second portion of the incoming light path from the environment. At least part of the second portion of the outgoing light path is at least partially coaxial with the second portion of the incoming light path.
  • the bidirectional optical subsystem is also configured to cause the at least partially non-coaxial first portion of the outgoing light path and the first portion of the incoming light path to be non-coaxial or less coaxial than the second portion of the outgoing light path and the second portion of the incoming light path.
  • the beam director includes dispersion components for directing in the one or more multiple directions the outgoing light and the incoming light based on respective one or more wavelengths.
  • the beam director is optically coupled to a light transmitter for providing the outgoing light and a light receiver for receiving the incoming light, and wherein the first portion of the outgoing light path and the first portion of the incoming light path have a first spatial offset at respective optical coupling with the light transmitter and the light receiver.
  • the first spatial offset is sufficiently large to avoid or reduce axial overlap between the outgoing light and the incoming light at the respective optical coupling.
  • the bidirectional optical subsystem includes or consists of an optical circulator.
  • the optical circulator includes (a) at least one input port optically coupled to the beam director along the outgoing light path, (b) at least one bidirectional port forming part of both the outgoing light path and the incoming light path, and (c) at least one output port optically coupled to the beam director along the incoming light path.
  • the second portion of the outgoing light path is coaxial with the second portion of the incoming light path at the at least one bidirectional port.
  • the first portion of the outgoing light path is non-coaxial with a second spatial offset with the first portion of the incoming light path at the respective optical coupling of the beam director with a said input port and a said output port.
  • the second spatial offset is sufficiently large to avoid axial overlap between the outgoing light and the incoming light at the respective optical coupling.
  • the bidirectional optical system includes collimation optics, and the outgoing light path and the incoming light path are coaxial at the collimation optics.
  • a method performed by a spatial profiling system which includes: directing outgoing light into an environment, the outgoing light comprising light having a first polarisation and substantially not comprising light having a second polarisation, orthogonal to the first polarisation; receiving, from the environment, incoming light comprising reflected outgoing light; routing the incoming light, comprising routing a first component of the reflected outgoing light over a first route and routing a second component of the reflected outgoing light over a second route, different to the first route, wherein the first component of the reflected outgoing light has the first polarisation and the second component of the reflected outgoing light has the second polarisation; providing the second component of the reflected outgoing light to a light receiver, for detection; and wherein routing the incoming light comprises passing at least a portion of the incoming light through a birefringent wavelength router.
  • the birefringent wavelength router is in the form of an arrayed waveguide grating, the arrayed waveguide grating including at least one slab and a waveguide array with birefringence sufficient to spatially separate the first component of the reflected outgoing light from the second component of the reflected outgoing light.
  • the birefringent wavelength router may include an input slab for receiving the outgoing light and may lack an output slab.
  • the outgoing light includes light at a first wavelength channel and a second wavelength channel, different to the first wavelength channel and wherein the directing outgoing light into an environment comprises differential directing of the first and second wavelength channels by the birefringent wavelength router.
  • the light at the first wavelength channel and the light at the second wavelength channel may be included in the outgoing light in different time windows or may be included in the outgoing light within the same time window, optionally simultaneously.
  • the directing outgoing light into an environment includes directing the outgoing light by the birefringent wavelength router.
  • the second beam director is a mechanical beam director.
  • the incoming light includes speckle and the method includes spatial sampling for mitigating one or more effects of the speckle.
  • a method by a spatial profiling system that includes: receiving, from an environment to be spatially profiled by the spatial profiling system, incoming light comprising reflected outgoing light comprising light of a first polarisation and light of a second polarisation, different to the first polarisation, wherein the outgoing light was light of the first polarisation and not light of the second polarisation; by polarisation dispersion, separating the light of the first polarisation from the light of the second polarisation, for detection of the light of the second polarisation substantially separately to the light of the first polarisation.
  • the reflected outgoing light includes first reflected outgoing light based on outgoing light at a first wavelength channel and second reflected outgoing light based on outgoing light at a second wavelength channel, different to the first wavelength channel; the first reflected outgoing light is received by the spatial profiling system from a first direction and the second outgoing light is received by the spatial profiling system from a second direction, different to the first direction; the method includes combining the first reflected outgoing light and the second reflected outgoing light into the same or substantially the same light path.
  • the first reflected outgoing light and the second reflected outgoing light may be received in different time windows or may be received in the same time window, optionally simultaneously.
  • the received incoming light comprises reflected outgoing light at each of the plurality of wavelength channels.
  • the plurality of wavelength channels form a set of wavelength channels creating at least one wavelength dimension in a field of view of the spatial profiling system; the first polarisation of the set of wavelength channels is spatially displaced, due to the dispersion, over a first range of spatial displacements; the second polarisation of the set of wavelength channels is displaced, due to the dispersion, over a second range of spatial displacements, different to the first range of spatial displacements.
  • the first range of spatial displacements and the second range of spatial displacements do not overlap.
  • the spatial displacement is due to separation during the separating of the reflected outgoing light.
  • the separation is by a birefringent arrayed waveguide grating comprising at least one slab.
  • the reflected outgoing light includes outgoing light internally reflected by the spatial profiling system and not by the environment.
  • a spatial profiling system including: a light transmitter configured to provide outgoing light, the outgoing light comprising light having a first polarisation and substantially not comprising light having a second polarisation, orthogonal to the first polarisation; a beam director for directing the outgoing light into an environment and receiving incoming light comprising reflected outgoing light; a wavelength router comprising an optical path with birefringence, the optical router configured to route a first component of the reflected outgoing light to a first route and route a second component of the reflected outgoing light to a second route, different to the first route, wherein the first component of the reflected outgoing light has the first polarisation and the second component of the reflected outgoing light has a second polarisation, orthogonal to the first polarisation; and a light receiver for the first route and not the second route, the light receiver including a light detector configured to detect the second component of the reflected outgoing light.
  • the wavelength router comprises a birefringent arrayed waveguide grating and wherein the wavelength router is at least a part of the beam director.
  • the arrayed waveguide grating comprises an input slab for receiving the outgoing light and an output slab, wherein the waveguide array with birefringence extends between the input slab and the output slab.
  • the outgoing light includes light at a first wavelength channel and light at a second wavelength channel, different to the first wavelength channel and wherein the wavelength router is configured to differentially direct the first and second wavelength channels.
  • the wavelength router is a first beam director configured to direct the outgoing light over a wavelength dimension and wherein the spatial profiling system comprises a second beam director configured to direct the outgoing light over a second dimension, the first and second dimensions providing a two-dimensional field of view.
  • the second beam director is a mechanical beam director.
  • the reflected outgoing light comprises speckle and the wavelength router is configured to route a third component of the reflected outgoing light to a third route.
  • the light detector configured to detect the second component of the reflected outgoing light is a first light detector of the light receiver and wherein the light receiver includes a second light detector, different to the first light detector, configured to detect the third component of the reflected outgoing light.
  • a processing system in communication with the first light detector and the second light detector, wherein the processing system is configured to spatially sample the environment based on signals from the first light detector and the second light detector.
  • first”, second and so forth are used to distinguish one entity from another and are not used to indicate or require any particular sequencing, in time, position or otherwise.
  • a first port and a second port has the same meaning as “a port and another port”.
  • a “port” or “optical port” is understood to mean an area of an optical component, such as the input slab or the output slab of the wavelength router, through which light passes, and does not necessarily require presence of a physical structure or component.
  • one port may be formed by an end of a waveguide or optical fibre, in which case the periphery of the port coincides with an internal surface of the waveguide or optical fibre, whereas another port may be within a larger area of an input slab or an output slab of a wavelength router, in which case the periphery of the port does not coincide with any structure of the waveguide.
  • “light” refers to electromagnetic radiation having optical frequencies, including far-infrared radiation, infrared radiation, visible radiation and ultraviolet radiation.
  • a designation of a view or orientation for instance a top view, a side view, horizontal or vertical is arbitrary for the purposes of illustration and does not suggest any required orientation.
  • Figure 1 illustrates an arrangement of a spatial profiling system.
  • Figure 2 illustrates an arrangement of a light source, for the spatial profiling system of Figure 1.
  • Figures 3A and 3B illustrate exemplary sensor heads.
  • Figures 4a, 4b and 4e each illustrate an embodiment of the exemplary sensor head of Figure 3A.
  • Figure 4c and 4d illustrate an embodiment of an exemplary on-chip AWG.
  • Figure 5 illustrates another embodiment of the exemplary sensor head of Figure 3A.
  • Figure 6 illustrates another embodiment of the exemplary sensor head of Figure 3A.
  • Figure 7 illustrates a variant of an on-chip modified arrayed waveguide grating (AWG) of the sensor heads of Figures 4-6.
  • AWG arrayed waveguide grating
  • Figure 8 illustrates another variant of an on-chip modified arrayed waveguide grating (AWG) of the sensor heads of Figures 4-6.
  • AWG arrayed waveguide grating
  • Figure 9 shows another exemplary sensor head.
  • Figures 10A-C illustrate examples of coaxial, non-coaxial and partially coaxial and partially non-coaxial light paths.
  • Figure 11 illustrates an arrangement of a spatial profiling system.
  • Figure 12 illustrates an arrangement of a light source, for the spatial profiling system of Figure 11.
  • Figure 13 illustrates an example arrangement of a sensor head, for the spatial profiling system of Figure 11.
  • Figures 14A and 14B each illustrate example sensor head components for the sensor head of Figure 13.
  • Figures 15A and 15B each illustrate in part an embodiment of a spatial profiling system.
  • Figure 16 shows example graphs of the angular separation resulting spatial separation caused by a birefringent AWG.
  • At least certain embodiments of the disclosed optical beam director include characteristics that provide a high directivity.
  • Directivity in the context of a LiDAR system refers to the amount of outgoing light (e.g. to the environment) relative to the amount of internally reflected light (e.g. by components of the system) detected by the system. Such internally reflected light is often unwanted.
  • a higher directivity corresponds to a lower return loss, which points to a LiDAR system that is more capable of distinguishing externally reflected light from unwanted internally reflected light as incoming light.
  • these embodiments may achieve the high directivity while maintaining an effective (e.g. sufficiently small) size and/or an effective (e.g.
  • optical beam director in a system for spatial profiling or in other words in a spatial estimation system.
  • Another example application of the optical beam director is in a system for free space optical communication or free space measurement, for example based on the Doppler Effect.
  • an optical system in particular a spatial profiling system, for directing light into an environment over one or two dimensions and detecting return light.
  • the one or two dimensions include a first dimension, for example along a y-axis which may be designated the vertical direction, and a second dimension, for example along an x-axis or horizontal direction.
  • a spatial profile may be formed by determining, based on the return light, a distance along a z- axis or a depth direction for each of a plurality of x-y coordinates.
  • the frame of reference used is not relevant - for example the one or two dimensions may be described using a polar coordinate system rather than a Cartesian coordinate system.
  • An example application of spatial profiling is to autonomous or semi- autonomous vehicles.
  • a spatial profiling system on or in a vehicle can estimate, from the vehicle’s perspective, a spatial profile of the environment in which the vehicle is to navigate, including the distance to environmental objects, such as an obstacle or a target ahead.
  • a spatial profiling system using light may be referred to as a light detection and ranging (LiDAR) system.
  • LiDAR light detection and ranging
  • a LiDAR system estimates the spatial profile (e.g. the z- axis or depth at each of a plurality of x-y co-ordinates) of an environment based on light
  • Embodiments of the described optical system are capable of steering light based on wavelength. For example one or more selected wavelength channels are directed in a first set of directions and one or more different selected wavelength channels are directed in a second set of directions, different to the first set. While the following description primarily refers to selecting a single wavelength channel (e.g. by tuning a wavelength-tunable laser), a person skilled in the art would appreciate that the description is also applicable, with minor modifications such as optically coupling together two or more wavelength-tunable lasers or filtering an optical frequency comb, to select two or more wavelength channels.
  • LiDAR involves transmitting light into the environment and detecting the light returned by the environment.
  • the system can determine information on the distance of reflecting surfaces within its field of view (FOV), for example the surface of an object or obstacle, the contour of the ground and/or the location of a horizon.
  • FOV field of view
  • a spatial estimation of part or all of the environment within the FOV may be formed based on this information.
  • the distance of a reflecting surface may be determined based on a round-trip-time of the light.
  • the round trip time of a pulse of light is determined, from which the range to a reflecting surface in the direction that the pulse of light was transmitted may be determined.
  • distance may be determined using frequency-modulated continuous wave (FMCW) or random-modulated continuous wave (RMCW) techniques.
  • FMCW frequency-modulated continuous wave
  • RMCW random-modulated continuous wave
  • the output of a continuous wave laser is modulated with a random binary sequence and the returned signal correlated against the known sequence, with the delay indicating the distance.
  • the random binary sequence may be a pseudo random binary sequence.
  • pulses of light that include a time-varying profile are emitted and the time varying profile used for distance determination.
  • the outgoing light includes a linear frequency chirp, or phase variations for detecting round trip time, instead of detecting the round trip time of a series of modulated pulses.
  • one of the dimensions relates to the range of a point from the origin of the outgoing light, whereas the other two dimensions relate to the two dimensional space (e.g. a space definable by a Cartesian (x, y) or polar (theta, phi) coordinate system) across which the light is directed.
  • the area or angular range over which the light is directed for detection of return light is a field of view of the spatial profiling system.
  • the field of view of the LiDAR system may be fixed or may be a controlled variable.
  • one or more beams of light are directed into the environment and the one or more optical beams are steered across two dimensions (i.e. a first dimension and a second dimension of a two-dimensional field of view), the combination of knowledge of the steering and the determined range providing information for spatial profiling.
  • the beam steering is based on wavelength, by directing light of a one wavelength in one direction and light of another wavelength in a different direction, by one or more suitable wavelength directing components.
  • the LiDAR system may determine speed or velocity information of an entity, for example a vehicle, where the LiDAR system is located and/or the reflecting surface in the environment.
  • the speed or velocity determination may be based on the detected light returned by the environment, either directly, for example based on Doppler-shifted signals contained in the returned light, or based on a change in distance determination with time. For example in a FMCW system a coherent beat tone of a chirped waveform will reveal the Doppler shift.
  • the speed information may be obtained or determined from external information that is not derived from the LiDAR system.
  • the outgoing light path and the incoming light path are coaxial.
  • the outgoing light path and the incoming light path have the same or overlapping optic axes.
  • Use of a coaxial system may result in an increase in collection efficiency of the return light, in comparison to non-coaxial systems.
  • a potential problem with coaxial systems is internal back-reflection along the outgoing light path being detected by the light detector. The higher the back-reflection the worse the directivity of the LiDAR system. Better directivity can be achieved by suppressing this internal back reflection.
  • Figure 1 illustrates an example arrangement of a spatial profiling system 100.
  • electrical connections e.g. analogue or digital signals
  • optical connections e.g. guided or free space optical transmission
  • the blocks represent functional components of the spatial profiling system 100. It will be appreciated that functionality may be provided by distinct or integrated physical components.
  • a light source may include an integrated amplifier and/or an integrated modulator.
  • the system 100 includes a light transmitter 101 for generating outgoing light
  • the light transmitter 101 may include a light source 102. In some embodiments, the light transmitter 101 may also include an optical amplifier 104 to amplify (provide gain to) light from the light source 102. In some embodiments the optical amplifier 104 is an Erbium-doped fibre amplifier (EDFA) of one or more stages. In other embodiments one or more stages of a semiconductor optical amplifier (SOA), a booster optical amplifier (BOA), or a solid state amplifier (e.g. a Nd:YAG amplifier) may be used. In some embodiments, the optical amplifier 104 may be omitted.
  • EDFA Erbium-doped fibre amplifier
  • the outgoing light 150 from the light transmitter 101 is received by a sensor head 107 at one or more input ports 121.
  • the sensor head 107 directs the outgoing light
  • the sensor head 107 also receives incoming light 153 along an incoming path 152 in the free space environment via the one or more ports 122. The sensor head 107 then sends the received incoming light 153 via one or more output ports 123 to a light receiver 109.
  • the sensor head 107 includes a beam director that directs outgoing light of different wavelengths in different directions over one or two dimensions based on wavelength. Additionally or alternatively, the beam director includes one or more components for directing outgoing light in different directions based on mechanical movement of the one or more components.
  • the sensor head 107 includes one or more components for conditioning the light. For example the sensor head 107 may include one or more collimators to receive diverging light from the beam director and provide conditioned light in the form of one or more collimated beams of light.
  • the incoming light 153 is received at the light receiver 109 via one or more output ports 123 of the sensor head 107.
  • the light receiver 109 may include a light detector 106.
  • the light detector 106 includes one or more photodetectors.
  • An example photodetector is an avalanche photodiode (APD).
  • the light detector 106 generates incoming electrical signals that are representative of the detected incoming light.
  • the light detector circuitry 106 may include a trans-impedance amplifier following the photodetector.
  • An analog-to-digital converter 108 may convert analogue incoming electrical signals to digital incoming electrical signals. The incoming digital signals are received and processed by a control system 110.
  • the light source 102 and the amplifier 104 may be also controlled by the control system 110.
  • the control system 110 controls aspects of operation of the other components in the system, for example one or more components of the senor head 107 and/or the light detector 106.
  • the control system 110 may determine the profile of the environment based on its control or knowledge of the outgoing light and based on the incoming light signals. For example, some embodiments utilise a round trip time for light to determine the depth dimension.
  • the control system 110 may communicate or store information for use by another processing system. The other processing system may then determine the spatial profile of the environment.
  • the spatial profiling system 100 separates the functional components into two main physical units, called herein an engine 111 and the sensor head 107.
  • the engine 111 and the sensor head 107 are substantially collocated. The collocation allows these components to be compactly packaged within a single unit or in a single housing.
  • the sensor head 107 is remote from the engine 111.
  • the engine 111 is optically coupled to the remote sensor head 107 via one or more guided optical connections, such as waveguides or optical fibres.
  • a spatial profiling system 100 may include a single engine 111 and multiple sensor heads. Each of the multiple sensor heads may be optically coupled to the engine 111 via respective guided optical connections. The multiple sensor heads may be placed at different locations and/or orientated with different fields of view.
  • Figure 2 illustrates an example arrangement of the light source 102.
  • the light source 102 includes a wavelength-tunable light source 202, such as a wavelength-tunable laser diode, providing light of a tunable wavelength.
  • the wavelength may be based on one or more electrical currents, for example the injection current into one of more wavelength tuning elements in a laser cavity, applied to the laser diode.
  • the light source 102 accordingly is configured to provide outgoing light at a selected one or more of multiple selectable wavelength channels (each represented by its respective centre wavelength Xi, X2, ... N).
  • the wavelength range of the wavelength-tunable light source is at least 20 nm, or at least 25 nm, or at least 30 nm, or at least 35 nm.
  • the resolution of the wavelength-tunable light source i.e. smallest wavelength step
  • the wavelength channels are at about 1550 nm. Other wavelengths may be used, for example about 905 nm or about 1310 nm.
  • the wavelength-tunable light source may be tuned from a first wavelength to a second wavelength within, for example, 2 microseconds, in some cases within 1 microsecond, within 0.5 microsecond, within 0.25 microsecond, or within 0.1 microsecond.
  • the wavelength tuning speed depends on the separation of the first wavelength and the second wavelength.
  • the wavelength-tunable light source may be wavelength-tunable within 8 nm/ms, such as under 80 nm/ms, under 800 nm/ms, under 8 nm/ps, or under 80 nm/ps.
  • the light source 102 may include a single tunable laser or more than one tunable laser (or other types of lasers). The light source 102 may select one wavelength channel at a time or may simultaneously provide two or more different selected wavelength channels (i.e. channels with different centre wavelengths).
  • the light source 101 may include a broadband light source and one or more tunable spectral filters to provide substantially continuous-wave (CW) light intensity at the selected wavelength(s).
  • the light source 101 may include one or more optical frequency combs.
  • the light source 101 includes multiple laser diodes, each wavelength-tunable over a respective range and whose respective outputs are combined to form a single output. The respective outputs may be combined using a wavelength combiner, such as an optical splitter or an arrayed waveguide grating (AWG).
  • AWG arrayed waveguide grating
  • the light source 102 is configured to provide the outgoing light to include at least one time-varying profile at the selected one or more of the multiple wavelength channels.
  • the time-varying profile may be used, for example, in determining the range to the reflecting surface or object.
  • the light source 101 includes a modulator 204 for imparting a time-varying profile on the outgoing light. This modulation may be in addition to any wavelength tuning as herein before described. In other words, the modulation would be of light at the tuned wavelength. It will be appreciated that the tuned wavelength may refer to a center frequency or other measure of a wavelength channel that is generated.
  • the time varying profile may, for example, be one or more of a variation in intensity, frequency, phase or code imparted to the outgoing light.
  • the light source 102 emits pulses of light, which pulses may include the time-varying profile.
  • the difference between the presence of a pulse and the absence of a pulse is a time varying profile for use in determining range, for example based on a detected round trip time of the light pulses.
  • the outgoing light from the light source 102 has a different form, for example individual pulses for detecting the round trip time of the individual pulses instead of detecting the round trip time of a series of modulated pulses.
  • the modulator 204 is a semiconductor optical amplifier (SOA) or a Mach Zehnder modulator integrated on a laser diode of the light source 102.
  • the electrical current applied to the SOA may be varied over time to vary the amplification of the CW light produced by the laser over time, which in turn provide outgoing light with a time-varying intensity profile.
  • the modulator 204 is an external modulator (such as a Mach Zehnder modulator or an external SOA modulator) to the laser diode.
  • the modulator 204 is a phase modulator.
  • the modulator 204 is located before the optical amplifier 104
  • the modulator may be located either before or after the optical amplifier 104 in the outgoing light path.
  • the light source 102 includes a laser having a gain medium into which an excitation electrical current is controllably injected for imparting a time-varying intensity profile on the outgoing light.
  • the light source 102, optical amplifier 104 and a modulator are provided by a sampled-grating distributed Bragg reflector (SG-DBR) laser.
  • SG-DBR sampled-grating distributed Bragg reflector
  • the SG-DBR laser may be controllable to provide 10 Gbps modulation, may operate across a 35 nm wavelength range and change from one wavelength channel to another in less than 100 nanoseconds.
  • the wavelength channels may have centre frequencies about 1 GHz or more apart.
  • the operation of the light source 102 such as one or both of the wavelength- tunable laser 202 (e.g. its wavelength) and the modulator 204 (e.g. the modulating waveform), may be controlled by the control system 110.
  • the control system may include an application specific device configured to perform the operations described herein, such as a configured programmable logic device, or a general purpose computing device with computer readable memory storing instructions to cause the computing device to perform the operations.
  • the instructions and/or data for controlling operation of the processing unit may be in whole or in part implemented by firmware or hardware elements, including configured logic gates.
  • the control system 110 may include, for example, a single computer processing device (e.g. a central processing unit, graphics processing unit, or other computational device), or may include a plurality of computer processing devices.
  • the control system 110 may also include a communications bus in data communication with one or more machine readable storage (memory) devices which store instructions and/or data for controlling aspects of the operation of the processing unit.
  • the memory devices may include system memory (e.g. a BIOS), volatile memory (e.g. random access memory), and non-volatile memory (e.g.
  • control system 110 includes one or more interfaces.
  • the interfaces may include a control interface with the light source 102 and a communication interface with the light detector 106.
  • light from the light source 102 is also provided to the detector 106 to provide a reference signal 155 via a light path 154 from the light source 102 to the detector circuitry 106.
  • the light from the light source may first enter a sampler (e.g. a 90/10 fiber-optic coupler), where a majority portion (e.g. 90%) of the light is provided to the beam director and the remaining sample portion (e.g. 10%) of the light is provided instead to the detector circuitry.
  • the detector circuitry may then be configured to inhibit detection of non-reflected light based on a difference in wavelength or modulation between the outgoing light and the non-reflected light.
  • the detection circuitry 106 includes one or more balanced detectors to coherently detect the reflected light mixed with reference light at the one or more balanced detectors.
  • the spatial profiling system 100 may therefore implement homodyne or heterodyne detection of the incoming light 153.
  • Other detection methods may be used, such as direct direction. In direct detection there is no need for the reference signal 155.
  • Figure 3 illustrates an exemplary sensor head 300, which may be an embodiment of the sensor head 107 of Figure 1.
  • the sensor head 300 includes an outgoing light path 307, along which outgoing light originating from the light transmitter 101 travels towards the environment.
  • the sensor head 300 further includes an incoming light path 309, along which incoming light reflected from the environment travels towards the light receiver 109.
  • the sensor head 300 includes a beam director 301, for directing light based on wavelength.
  • the beam director 301 receives the outgoing light 151 from the light transmitter 101 at a first port 311.
  • the sensor head 300 includes a bidirectional optical subsystem 303.
  • the bidirectional optical subsystem 303 may include, for example, an optical circulator with an input port 312 optically connected to receive the outgoing light 151 provided by the beam director 301, a bidirectional port 313 for sending the outgoing light 151 towards the environment and receiving the incoming light 153 reflected from the environment, and an output port 314 for sending the incoming light 153 towards the beam director 301.
  • the received incoming light 153 at the beam director 301 is sent towards the light receiver 109 via a second port 315 of the beam director 301.
  • the output port 314 is spatially offset (e.g. laterally offset) from the input port 312 by a first spatial offset.
  • the first spatial offset may be sufficiently large to avoid or reduce axial overlap between the incoming light and the outgoing light, for example respectively at the input port 312 and the output port 314.
  • the first spatial offset may be larger than a spot size (e.g. beam diameter, full-width at half maximum) of the light beam exiting and/or the light beam entering the beam director 301.
  • the second port 315 is spatially offset (e.g. laterally offset) from the first port 311 by a second spatial offset.
  • the second spatial offset may correspond to or be based on the first spatial offset.
  • the first spatial offset and the second spatial offset may be the same.
  • a change in the first spatial offset e.g. by locating the output port 314 close to or further from the input port 312 may cause a corresponding change in the second spatial offset.
  • the second spatial offset may be sufficiently large to avoid or reduce axial overlap between the incoming light and the outgoing light, for example respectively at the first port 311 and the second port 315.
  • the second the spatial offset may be larger than the spot size of the light beam arriving at the bidirectional optical subsystem 303 from the beam director 301 or arriving at the beam director 301 from the bidirectional optical subsystem 303.
  • the bidirectional optical subsystem 303 may include one or more non-reciprocal optics, for example components for separating the light into distinct polarisations and directing the individual polarisations through the core, such as one or more individual birefringent crystals and Faraday rotators. Examples of optical circulators are described in PCT/AU2018/051175, published as WO 2019/084610 A1 (Baraja Pty Ltd), which is hereby incorporated herein by reference in its entirety.
  • the bidirectional optical subsystem 303 may include a 2x1 coupler, instead of a circulator.
  • the two ports on one side of the 2x1 coupler function as, respectively, the input port and the output port of the circulator.
  • the 1 port on the other side of the 2x1 coupler functions as the bidirectional port of the circulator.
  • Figure 3 shows a simplified outline of an embodiment of a sensor head.
  • the sensor head 300 may include zero or one or more optical components in between the beam director 301 and the bidirectional optical subsystem 303.
  • the outgoing light and/or the incoming light may be directly sent between the beam director 301 and the bidirectional optical subsystem 303, or indirectly sent via one or more other optical components.
  • the sensor head 300 may include zero or one or more optical components in between the bidirectional optical subsystem 303 and the environment.
  • the sensor head 300 may include zero, one or more optical components in between the beam director 301 and the light receiver 109.
  • the beam director 301 includes one or more distinct dispersive components, such as one or more individual gratings and/or prisms and/or grisms.
  • the beam director 301 may therefore direct the outgoing light 151 based on its wavelength, by diffraction and/or refraction of the outgoing light 151.
  • the beam director may therefore be viewed as directing the outgoing light 151 over a wavelength dimension.
  • the beam director 301 may additionally or alternatively include one or more components for directing light based on physical movement, for example a scanning mirror arrangement and/or one or more physically rotating dispersive components.
  • the beam director 301 may therefore be viewed as directing the light over a mechanical dimension.
  • the outgoing light path 307 for the outgoing light 151 between the beam director 301 and the bidirectional optical subsystem 303 includes a plurality of light paths distributed across the range of operation of the beam director 301.
  • one set of light paths may correspond to one wavelength channel and another set of light paths correspond to another wavelength channel.
  • the set of light paths corresponding to a wavelength channel may consist of one light path, for example in a 2D scanning arrangement based on wavelength, or may include a plurality of light paths with each of the plurality of light paths corresponding to one wavelength channel and a plurality of positions across a mechanical dimension.
  • the light conditioning element 305 may include a collimator.
  • the collimator may be formed by one or more distinct optical components, such as one or more lenses for collimating the outgoing light.
  • Sensor heads with distinct optical components may present assembly complexity in, for example, aligning the distinct components with each other. Such sensor heads with distinct optical components may also be relatively bulky in size and/or have a relatively high cost of production, as large active areas are required for a large aperture, which is desirable for providing a larger field of view. It will be understood that the above issues may become more severe when more distinct optical components are required in the sensor head, for example, to provide a desired amount of light dispersion. Accordingly part or all elements of the sensor head 107 may be designed on an integrated circuit chip, e.g. in a silicon on insulator (SOI) photonic platform. In other words, a plurality of the distinct optical components of the sensor head mentioned above may be implemented instead as integrated components. Furthermore, one or more components of the engine 111 may be integrated with components of the sensor head 107. For example one or more components the optical amplifier 104 and/or the modulator 204 may be integrated with at least the beam director 301.
  • SOI silicon on insulator
  • the bidirectional optical subsystem 303 By placing the bidirectional optical subsystem 303 after, or in other words downstream of, the beam director 301 in the outgoing light path 307 (i.e. placing the bidirectional optical subsystem 303 before, or upstream of, the beam director 301 in the incoming light path 309), undesired back-reflection of the outgoing light within the sensor head 300 (e.g. reflected by one or more surfaces within the beam director 301 up until the bidirectional port 313) may be back-reflected towards the light transmitter 101 , rather than towards the light receiver 109.
  • the outgoing light path 307 may include, for example between the light transmitter 102 and port 313, an optical isolator to reduce effects of such back-reflection while allowing passage of outgoing light 151.
  • the sensor head is configured to exhibit a return loss of -60 dB or lower. In some embodiments, the sensor head is configured to exhibit a return loss of -70 dB or lower. In some embodiments, the sensor head is configured to exhibit a return loss of -80 dB or lower. In some embodiments, the sensor head is configured to exhibit a return loss of 90 dB or lower.
  • light paths that are “coaxial” refers to light paths that share the same optic axis.
  • the light paths may be of any length, including infinitesimally short, may be linear or not linear.
  • Light paths may be coaxial regardless of beam size or travel direction of the light.
  • outgoing light travelling in a portion of an outgoing light path and being well-collimated and having a smaller spot size may share a coaxial light path with incoming light travelling in a portion of an incoming light path and being less collimated and having a larger spot size.
  • the incoming light and the outgoing light have an axial overlap such that they travel through an optical component at substantially the same region or location, typically in opposite directions.
  • This overlap may facilitate collection of incoming light.
  • the incoming light and the outgoing light may have less or no axial overlap. This non-overlap may facilitate rejection or isolation of incoming light.
  • Figure 10A illustrates examples of light paths, viewed in cross-section, that are coaxial.
  • Figure 10B illustrates examples of light paths, viewed in cross-section, that are non-coaxial.
  • Figure 10C illustrates examples of light paths, viewed in cross-section, that are partially coaxial or equivalently partially non-coaxial.
  • the optical axes of the two light paths indicated by the dot at the centre of each light path, are parallel.
  • both light paths are circular in cross-section and one light path is smaller in diameter than the other. It will be appreciated that the light paths may be other shapes and other respective sizes.
  • Figures 4(a)-(b) illustrate an exemplary sensor head 400, which may be an embodiment of the sensor head 300 of Figure 3A.
  • Figure 4(a) illustrates a top view of the sensor head 400
  • Figure 4(b) illustrates a side view of the sensor head 400.
  • the beam director is an on-chip beam director 401.
  • the beam director 401 is an Echelle grating.
  • the beam director 401 is in the form of a modified on-chip arrayed waveguide grating (AWG) fabricated, for example, in any one or more of Si, SiC>2 and SiN, on a substrate 410.
  • a modified AWG may be an AWG lacking one or more AWG components.
  • the modified AWG lacks output fibre/waveguides optically coupled to the output slab 406. That is, one end of the modified AWG in this example terminates at the output slab 406 that would in a regular AWG be otherwise optically coupled to output fibre/waveguides.
  • the on-chip beam director 401 includes an input slab 402.
  • the outgoing light 151 from the light transmitter 101 is received at a first position 411 on a first edge 421 of the input slab 402, e.g. via an optical fibre/waveguide 431.
  • the outgoing light diffracts within the input slab 402 towards a second edge 422, at an opposite end of the input slab 402 to the first edge 421.
  • the diffracted outgoing light is received by first ends 423 of an array of waveguides 404 of different path lengths. After propagating in the array of waveguides 404, the outgoing light output from second ends 424 of the array of waveguides 404, is received at a first edge 425 of an output slab 406.
  • the outgoing light from the array of waveguides diffracts within the output slab 406 towards a second edge 426, opposite to the first edge 425, of the output slab 406.
  • the outgoing light interferes at the second edge 426 of the output slab 406 to form wavelength-directed outgoing light 151.
  • the second edge 426 may be viewed as forming a port of the beam director.
  • the modified AWG includes dispersive components for directing the outgoing light 151 based on wavelength.
  • the bidirectional optical subsystem is in the form of an on-chip circulator 403, integrated with the on-chip beam director 401.
  • the on-chip circulator 403 may be an embodiment of circulator as described in the incorporated international patent application PCT/AU2018/051175, fabricated on the substrate 410.
  • the wavelength-dispersed outgoing light is received at an input port 412 of the circulator 403.
  • the input port 412 extends along the second edge 426, so as to receive the outgoing light 151 that has been directed by the beam director 401.
  • the on-chip circulator 403 is immediately adjacent to the second edge 426, so that the input port 412 is coterminous with the second edge 426.
  • the input port 412 is spaced apart from the second edge 426.
  • the wavelength-dispersed outgoing light is then directed to a bidirectional port 413 of the circulator 403.
  • the wavelength-dispersed outgoing light 151 from the bidirectional port 413 of the circulator 403 is collimated by the light conditioning element, for example collimation optics or a focusing lens 405, before being sent to the environment.
  • the incoming and outgoing light paths may be coaxial through light conditioning element and at the bidirectional port 413.
  • the incoming light 153 reflected from the environment is collected by the focussing lens 405 and then sent to the bidirectional port 413 of the circulator 403.
  • the incoming light 153 received at the bidirectional port 413 is directed to an output port 414 of the circulator 403, the output port 414 being spatially offset (e.g. laterally offset) from the input port 412.
  • the spatial offset is larger than a spot size of the light beam at the second edge 426 of the output slab 406 (i.e. the edge interfacing the output slab 406 with the circulator 403) and/or the first edge 421 of the input slab 402 (i.e.
  • the lateral offset of the input port 412 and output port 414 of the circulator 403 may be in the order of 20-40 pm.
  • the incoming light received at the output port 414 of the circulator 403 retraces the outgoing light path but in a backward direction and with a spatial offset through the output slab 406.
  • the incoming light diffracted within the output slab 406 is received at the second ends 424 of the array of waveguides 404.
  • the incoming light propagated through the array of waveguides 404 is then received at the first ends 423 of the array of waveguides 404.
  • the incoming light diffracts within the input slab 402 towards the first edge 421 of the input slab 402 at a second position 415 that is spatially offset (e.g. laterally offset) from the first position 411 where the outgoing light is received at the input slab 402 from the light transmitter 101.
  • Figure 4(a) illustrates the outgoing light 151 (depicted in dotted lines) and incoming light 153 (depicted in dashed lines) propagating in their light paths through the on-chip AWG 401 only at a single wavelength channel.
  • Figures 4(c) and 4(d) Propagation of light at multiple wavelength channels is illustrated in Figures 4(c) and 4(d).
  • Figures 4(a), 4(b), 4(c) and (4d) are intended to be viewed together to illustrate incoming light (depicted in dotted lines) and outgoing light (depicted in dashed lines) at different wavelength channels propagating through the on-chip AWG 401, hence through the sensor head 400.
  • Figure 4(c) illustrates outgoing light 151 through the on-chip AWG 401 at multiple wavelength channels
  • Figure 4(d) illustrates incoming light 153 through the on-chip AWG 401 at multiple wavelength channels.
  • Like components and features to those described with reference to Figures 4(a) and 4(b) are shown with like reference numerals.
  • the on-chip AWG 401 directs outgoing light 151 at different wavelength channels at different directions. Based on interference of light at the second ends 424 of the array of waveguide 404, the on-chip AWG 401 disperses or separates light of different wavelength channels, as the outgoing 151 light propagates from the first edge 425 towards the second edge 426 of the output slab 406. For example, outgoing light 151a at a first wavelength channel X1 is directed to a first direction. Outgoing light 151b at a second wavelength channel A2 is directed to a second direction, different to the first direction. Outgoing light 151c at a third wavelength channel A3 is directed to a third direction, different to the second direction and the first direction.
  • the dispersion in angular terms may be anywhere between 4 and 6 microdegrees per GHz of optical frequency range. This angular dispersion corresponds to 20 to 30 milli-degrees over approximately 5 THz of optical frequency range (equivalent to a wavelength range of 40 nm at wavelength channels nearby 1550 nm).
  • the length L of the output slab 406 (or the region between the second ends 424 of waveguide array 404 and the focal plane or line in the embodiment of Figure 7 or 8) may range between 20-200 mm.
  • the dispersion in spatial terms may be 0.3 - 3.0 microns per GHz of optical frequency range. This spatial dispersion corresponds to 1.5 to 15 mm over approximately 5 THz of optical frequency range (equivalent to a wavelength range of 40 nm at wavelength channels nearby 1550 nm).
  • the on-chip AWG 401 receives incoming light 151 at the different wavelength channels at different directions, corresponding to those directions of the outgoing light 151. Based on reciprocity of light, incoming light 153 of the different wavelength channels on reception traces back through the output slab 406 in reverse direction to their corresponding outgoing light paths. For example, incoming light 153a at the first wavelength channel X1 propagates through the output slab 406 in reverse direction to outgoing light 151a. Incoming light 153b at the second wavelength channel A2 propagates through the output slab 406 in reverse direction to outgoing light 151b. Incoming light 153c at the third wavelength channel A3 propagates through the output slab 406 in reverse direction to outgoing light 151c.
  • the light at different wavelength channels recombines as it propagates from the second ends 424 to the first ends 423 of the array of waveguides and re-focusses to the second position 415 of the input slab 402. While Figures 4(c) and 4(d) each illustrate three wavelength channels, the on-chip AWG 401 is configured to receive and/or direct light of different wavelength channels sequentially or simultaneously. That is, the on-chip AWG 401 may receive and/or direct light of one, more or all of the different wavelength channels at a time.
  • FIG. 4(e) illustrates another embodiment of sensor head 450.
  • like components and features to those described with reference to Figures 4(a) to 4(d) are shown with like reference numerals.
  • the on-chip AWG 401 includes one or more additional fibres or waveguides 433 for collecting the speckled or diffused light.
  • some of the incoming light (such as specular component of incoming light propagating through the arrays of waveguides 404 in a fundamental mode) is received at the second position 415 of the input slab 402 and collected by the associated optical fibre/waveguide 432.
  • some of the incoming light (such as speckled or diffused component of incoming light propagating through the arrays of waveguides 404 in higher order modes) is received at one or more positions 416 further spatially shifted from the position 415 of the input slab 402.
  • the incoming light received at the one or more further spatially shifted positions 416 is collected by the one or more additional fibres of waveguide 433.
  • a measure of light received at the one or more further spatially shifted positions 416 is a measure of the level of specularity.
  • spatial sampling may be used, for example, by collecting the incoming light at one or more of the spatially shifted positions. Details of speckle effect mitigation methods are described in US patent application no. 63/304305 (Baraja Pty Ltd), which is hereby incorporated herein by reference.
  • Figure 5 illustrates another exemplary sensor head 500, which may be an embodiment of the sensor head 300 of Figure 3A.
  • Figure 5(a) illustrates a top view of the sensor head 500
  • Figure 5(b) illustrates a side view of the sensor head 500.
  • the light conditioning element in addition to the collimating optics (e.g. the collimation optics or the focusing lens 405), the light conditioning element in this example also includes beam-shaping optics.
  • the outgoing light and incoming light transmission between the on-chip AWG 401 and the on-chip circulator 403 is the same as that for Figure 4 and is not repeated for succinctness.
  • the outgoing light from the circulator 403 is first received by a beam-shaping component 501 (e.g. a cylindrical mirror or lens) for increasing numerical aperture in one dimension. That is, the outgoing light is expanded by the beam-shaping component 501 in one dimension.
  • the beamshaping component 501 may be an on-chip component, fabricated on the substrate 410.
  • the outgoing light is then collimated by the collimation optics or focusing lens 405 before being sent to the environment.
  • Figure 5(c) which depicts a perspective view of the focusing lens 405
  • diverging outgoing light from the beamshaping component 501 has an elliptical power density with increasing beam width towards the focusing lens 405.
  • the focusing lens 405 collimates the diverging outgoing light into collimated outgoing light, e.g. towards the environment.
  • Incoming light e.g. from the environment, is collected by the focusing lens 405.
  • the focusing lens 405 converges incoming light.
  • the converged incoming light is provided to the beam- shaping component 501 , e.g. along the incoming light path towards the light receiver.
  • an increased numerical aperture may improve light collection efficiency (e.g. more power of the incoming light reflected from the environment may be collected), which may relieve the output power requirement from the light transmitter 101 (e.g. less peak/average output power is required to meet the detection range requirements).
  • Less peak output power may further facilitate a lower constrain on directivity, which may help for the sensor head design with smaller optics.
  • the incoming light path 309 of the system i.e. from the environment to the light receiver 109
  • the incoming light reflected from the environment is collected by the focussing lens 405 and then sent to the beam-shaping component 501.
  • the incoming light is compressed along the dimension over which the outgoing light is expanded by the beam-shaping component 501.
  • the compressed incoming light is then received at the bidirectional port 413 of the circulator 403 for further transmission.
  • the spatial profiling system 100 includes a single beam director and optical circulator pair, for example as shown in Figures 4 and 5.
  • a single beam director and optical circulator pair for example as shown in Figures 4 and 5.
  • Figure 6 illustrates another exemplary sensor head 600 in its top view, which may be an embodiment of the sensor head 300 of Figure 3A.
  • the beam director for sensor head 600 includes a set of a plurality of modified on-chip AWGs.
  • a beam direction 601 of the sensor head 600 includes four on-chip modified AWGs 601 A, 601 B, 601C and 601 D, each of which include like components and features to the on-chip modified AWG 401 described with reference to Figure 4, for directing the outgoing light over a larger spatial extent compared to the single on-chip modified AWG (e.g.
  • Each of the multiple on-chip modified AWGs directs light with the same or different wavelength ranges. Whilst the embodiment of Figure 6 has four AWGs, in other embodiments there may be two, three or more than four AWGs.
  • the senor head 600 also includes a circulator 603, similar to the circulator 403 but occupying a larger spatial extent.
  • the circulator 603 includes multiple input ports (612A, 612B, 612C and 612D) and multiple output ports (614A, 614B, 614C and 614D) at a first end of the circulator 603 for receiving the outgoing light from and sending the incoming light to the corresponding on-chip modified AWG (601 A, 601 B, 601C and 601 D) and multiple bidirectional ports (not shown) at a second end, opposite to the first end, of the circulator 603 for sending the outgoing light and receiving the incoming light to the light conditioning element.
  • the light conditioning element includes a beam-shaping component 607, which is similar to the beam-shaping component 501 but occupying a larger spatial extent.
  • the beam-shaping component 607 is omitted.
  • the light conditioning element may also include a collimating component 605, which is similar to the collimation optics or focusing lens 405 but occupying a larger spatial extent.
  • FIG. 4 to 6 While the embodiments of Figures 4 to 6 include one circulator for one or more beam directors, in other embodiments a two or more circulators are provided for a beam director. For example, two circulators may be fabricated adjacent to each other along the edge of the output slab of an AWG in the form described above.
  • the output slab of the previously described on-chip modified AWG may be further omitted to reduce footprint of the beam director and hence the sensor head. That is, one end of the modified AWG in these embodiments terminates at the second ends of the array of waveguides that would in a regular AWG be otherwise optically coupled to the output slab.
  • Figures 7 and 8 illustrate two variants of the on-chip modified AWG without the output slab (701 and 801), each of which may be used to replace one or more of the on-chip modified AWGs (401, 401 A, 401 B, 401C and 401 D) in the previously described sensor heads 400, 500 and 600.
  • like components and features to those described with reference to Figure 4 are shown with like reference numerals.
  • Figure 7 illustrates an on-chip modified AWG 701 without an output slab.
  • the on-chip modified AWG 701 is otherwise similar to the on-chip AWG 401, such as that illustrated in Figures 4(c) and 4(d). Like components and features to those described with reference to Figure 4 are shown with like reference numerals.
  • the on-chip modified AWG 701 terminates at the second ends 424 of the array of waveguides 404.
  • the on- chip modified AWG 701 therefore has a smaller size than the on-chip AWG 401.
  • Light exiting the second ends 424 in the on-chip modified AWG 701 is coupled to free-space, which is focused to a horizontal focal plane or line 702 external to the on-chip modified AWG 701. That is, the outgoing light is focused by the on-chip modified AWG 701 in the horizontal direction (i.e. X direction as illustrated in Figure 7).
  • the variant 701 is so- called a focussing variant of the on-chip modified AWG.
  • the variant 701 has a vertical focal plane or line 703 at (or before) the second end 424 of the array of waveguides 404 in the outgoing light path.
  • the outgoing light is diverged by the on-chip modified AWG 701 at the second end 424 of the array of waveguides 404 in the vertical direction (i.e. Y direction as illustrated in Figure 7).
  • This astigmatism may be compensated by the following light conditional element or elements (e.g. the collimation optics focusing lens 405).
  • FIG. 8 illustrates an on-chip modified AGW 801 without an output slab, which has a horizontal focal plane or line 802 internal to the on-chip modified AGW 801.
  • the horizontal focal plane or line 802 is within the array of waveguides 404. That is, the outgoing light has a virtual focus within the array of waveguides 404and is diverged by the on-chip modified AWG 801 in the horizontal direction (i.e. X direction as illustrated in Figure 8).
  • the variant 801 is so-called a diverging variant of the on-chip modified AWG.
  • the variant 801 has a vertical focal plane 803 at (or before) the second end 424 of the array of waveguides 404 in the outgoing light path.
  • the outgoing light is diverged by the on-chip modified AWG 801 at the second end 424 of the array of waveguides 404 in the vertical direction (i.e. Y direction as illustrated in Figure 7).
  • the astigmatism may be compensated by the following light conditional element (e.g. the collimation optics or focusing lens 405).
  • the embodiments described so far have included a sensor head for directing light over a (first) dimension, which is based on wavelength-based dispersion of the outgoing light and so called a wavelength dimension.
  • the sensor head may include mechanisms to direct light over another (second) dimension, which dimension is or at least includes a component perpendicular to the first dimension.
  • the mechanism may also operate based on wavelength, so as to provide a second wavelength dimension.
  • the mechanism may operate by mechanical movement, so as to provide a mechanical dimension.
  • Figure 9 shows another exemplary sensor head 900, which includes the sensor head 300, 350, 400, 500 or 600 described with reference to Figures 3A, 3B and 4-6, respectively (the description of which is not repeated for succinctness) and a mechanical beam director 901, for example a physically rotating reflector (e.g. mirror) or rotating prism arrangement.
  • the mechanical beam director 901 receives the outgoing light from the light conditioning element of the sensor head 300, 350, 400, 500 or 600, which has been directed across a first dimension (e.g. wavelength dimension), and steers it across a second dimension orthogonal to the first dimension (e.g. mechanical dimension).
  • the mechanical dimension when using a pulsed light source, may create a plurality of rows of image points, including a row 903 for light at Xi and including a row 904 for light at XN.
  • the columns in the image plane 902 are formed by the wavelength dispersion.
  • the dispersion across the wavelength dimension may occur at a much faster cycle rate than the cycle rate for steering across the mechanical dimension.
  • a beam director which includes two wavelength dimensions may be formed by replacing the mechanical beam director 901 with a dispersive element.
  • the dispersive element may for example be or include one or more diffraction gratings, to further direct different groups of wavelength channels of the outgoing light from the light conditioning element across the second wavelength dimension.
  • the mechanical movement to provide a mechanical dimension is movement of, for example rotation of, the beam director.
  • the beam director may rotate about an axis through and substantially perpendicular to a plane of the wavelength dimension.
  • the substrate 410 and optionally the lens 405 may be located on rotatable platform that spins about an axis A.
  • Figure 11 illustrates an example arrangement of a spatial profiling system 100A.
  • electrical connections e.g. analogue or digital data or control signals
  • optical connections e.g. guided or free space optical transmission
  • Optical input ports and optical output ports of components are represented by solid-filled circles.
  • the spatial profiling system 100A includes a light transmitter 101 A, a sensor head 103A, a light receiver 104A and a processing and control system 105A.
  • the spatial profiling system 100A forms an outgoing light path P1 for outgoing light L1 that is provided to an environment for spatial profiling and an incoming light path P2 for incoming light L2 that is provided to the light receiver 104A for detection.
  • the incoming light L2 includes outgoing light L1 that has been reflected by the environment.
  • the light transmitter 101A includes a light source 102A for generating the outgoing light L1.
  • the light source 102A may include one light generator or more than one light generator, for example one or more laser diodes.
  • the light source 102A is wavelength-tunable, for selectively providing light at one or more of a range of selectable wavelengths.
  • the light source may include one or more wavelength-tunable laser diodes.
  • the light transmitter 101 A includes one or more optical amplifiers for providing gain to the outgoing light L1 and/or one or more optical modulators for imparting a time-variation to at least one property of the outgoing light L1.
  • Outgoing light L1 from the light transmitter 101 A is provided to the sensor head 103A.
  • the outgoing light L1 may be provided directly from the light transmitter 101 A to the sensor head 103A, or indirectly via one or more other optical components in the outgoing light path P1 , such as a collimator.
  • the sensor head 103A directs the outgoing light L1 to the environment.
  • the sensor head 103A includes a beam director for controlling the direction of the outgoing light L1.
  • the sensor head 103A may include one or more wavelength-based beam directors that direct one wavelength of the light source 102A in one direction and another wavelength in another direction.
  • a range of wavelengths may therefore be directed in a range of directions.
  • the beam director there may be a one-to-one correspondence between the selectable wavelengths and the directions, or one set of a plurality of selectable wavelengths may be directed in a single direction and another set selectable wavelengths directed in another direction.
  • the sensor head 103A may also or instead include one or more beam directors that include one or more mechanically moveable components to control the direction of the outgoing light, for example one or more scanning mirrors and/or rotating or tilting dispersive or diffractive components. Accordingly, the outgoing light L1 is directed in one direction at one time when the mechanically moveable components are in one position or orientation and directed in another direction at another time when the mechanically moveable components are in another position or orientation, and so forth to provide a range of directions.
  • one or more beam directors that include one or more mechanically moveable components to control the direction of the outgoing light, for example one or more scanning mirrors and/or rotating or tilting dispersive or diffractive components. Accordingly, the outgoing light L1 is directed in one direction at one time when the mechanically moveable components are in one position or orientation and directed in another direction at another time when the mechanically moveable components are in another position or orientation, and so forth to provide a range of directions.
  • the sensor head 103A may include both a wavelength-based beam director and a mechanical beam director.
  • the sensor head 103A may include one or more diffractive and/or dispersive components that direct light based on wavelength, with the directed light provided onto a scanning mirror for mechanical beam direction.
  • at least one diffractive or dispersive component for wavelength-based beam direction is mounted on a rotating platform, with rotation of the diffractive or dispersive component causing mechanical beam direction.
  • Spatial profiling systems with both wavelength and mechanical beam direction components may be viewed as having a wavelength dimension and a mechanical dimension.
  • the wavelength dimension and a mechanical dimension may be orthogonal or substantially orthogonal.
  • the sensor head 103A also receives incoming light L2 along the incoming light path P2.
  • the sensor head 103A includes a bidirectional port 108A through which both the outgoing light L1 and the incoming light L2 traverse.
  • the outgoing light path P1 and the incoming light path P2 coincide or overlap at least at the bidirectional port of the sensor head 103A.
  • the outgoing light path P1 and the incoming light path P2 may share a common optical axis or have parallel optical axes at the bidirectional port. This sharing of a common optical axis or the presence of parallel optical axes and coinciding or overlapping light paths may continue through at least one beam director of the one or more beam directors of the sensor head 103A.
  • the sensor head 103A separates the incoming light L2 from the outgoing light L1.
  • the separation may be achieved by the sensor head 103A directing the incoming light L2 to a different port to the port where the incoming light L1 is received (as represented by the separated ports in Figure 11) and/or by providing the incoming light L2 from the sensor head 103A so that the light path P2 is not parallel to the light path P2.
  • this separation occurs at another location along the light paths P1 , P2, for example proximate or within the light receiver 104A.
  • the outgoing light path P1 and the incoming light path P2 do not coincide or overlap at or within the sensor head 103A.
  • the sensor head may optionally be split into two physical components, one for providing the outgoing light path P1 and one for providing the incoming light path P2.
  • the incoming light L2 traversing the incoming light path P2 is received by the light receiver 104A.
  • the light may be provided directly from the sensor head 103A to the light receiver 104A, or indirectly via one or more other optical components in the incoming light path P2, such as an optical filter.
  • the light receiver 104A includes a light detector 106A.
  • the light detector generates a signal S1 based on the incoming light L2.
  • the signal S1 is representative of the information carried by the detected incoming light L2 for determining the distance to the reflecting surface.
  • the signal S1 may be an analogue data signal.
  • the light detector 106A may include one or more photodetectors.
  • An example photodetector is an avalanche photodiode (APD).
  • the light receiver 104A may include two photodiodes for balanced detection.
  • an analog-to-digital converter 107A converts the analogue data signal to a digital signal S2.
  • light from the light source 102A is also provided to the detector 106A to provide a reference light signal or local oscillator light signal L3.
  • the local oscillator light signal L3 is provided to the light receiver 104A.
  • the detector circuitry may then be configured to inhibit detection of non-reflected light based on a difference in wavelength or modulation between the outgoing light and the non-reflected light.
  • the light detector 106A may include one or more balanced detectors to coherently detect the reflected light in the incoming light L2 mixed with the reference light.
  • the spatial profiling system 100A may therefore implement coherent (homodyne or heterodyne) detection of the incoming light L2.
  • the light detector 106A is configured to recover, or provide a measure of, both the amplitude (E) and phase ( ⁇
  • the light detector 106A includes an in-phase and quadrature (IQ) optical demodulator.
  • the IQ demodulator is configured to combine a first portion of the incoming light L2 with a first (in-phase) portion of the reference light L3, for example via an optical coupler, to provide a first combination.
  • the IQ demodulator is further configured to combine a second portion of the incoming light L2 with a second (quadrature) portion of the reference light L3, for example via another optical coupler, to provide a second combination.
  • the first (in-phase) portion and the second (quadrature) portion of the reference light L3 are phase-separated by 90 degrees of pi/2 radians.
  • the IQ demodulator may include an optical path length, such as an optical delay line, to facilitate the phase separation.
  • the IQ demodulator may include one or more multi-mode interference (MMI) couplers to facilitate the phase separation.
  • MMI multi-mode interference
  • the IQ demodulator is configured to generate an electrical in-phase signal (of magnitude I) based on the first combination, and an electrical quadrature signal (of magnitude Q) based on the second combination.
  • the in- phase signal (of magnitude I) and the quadrature signal (of magnitude Q) can be further combined, for example upon digitization by the ADC 107A discussed below, to recover the amplitude (E) and phase ( ⁇
  • ) are all a function of time.
  • Other detection methods may be used, such as direct direction. In direct detection there is no need for the local oscillator light signal L3.
  • the digital signals S2 are received and processed by the processing and control system 105A.
  • the processing and control system 105A may, based on the digital signal S2, determine a distance to a reflecting surface (or object) in the environment.
  • the light transmitter 101 A may be controlled by the processing and control system 105A by a control signal over a control line C1.
  • the processing and control system 105A also controls aspects of operation of the other components in the system, for example one or more components of the sensor head 103A over a control line C2 and/or one or more components of the light receiver 104A over a control line C3.
  • Two or more of the control lines C1 to C3, optionally with other control lines, may be combined into a control bus, with the controlled components being individually addressable.
  • the processing and control system 105A may determine the distance to a reflecting surface of the environment based on its knowledge of the control of components of the spatial profiling system 100A.
  • the processing and control system 105A may determine a spatial profile of the environment based on a collection of distance determinations.
  • the processing and control system 105A may include a communications interface with another data processing system, and communicate signals with the other data processing system to enable it to perform the spatial profiling determination based on the distance determinations by the processing and control system 105A, or enable it to perform the distance and/or spatial profiling determination.
  • the processing and control system 105A may include one or more application specific devices configured to perform the operations described herein, such as one or more manufactured or configured programmable logic devices, such as application specific integrated circuits or field programmable gate arrays, or one or more general purpose computing devices, such as microcontrollers or microprocessors, with computer readable memory storing instructions to cause the computing device or devices to perform the operations.
  • application specific devices configured to perform the operations described herein, such as one or more manufactured or configured programmable logic devices, such as application specific integrated circuits or field programmable gate arrays, or one or more general purpose computing devices, such as microcontrollers or microprocessors, with computer readable memory storing instructions to cause the computing device or devices to perform the operations.
  • the instructions and/or data for controlling operation of the processing unit may be in whole or in part implemented by firmware or hardware elements, including configured logic gates. These elements may be integrated on a common substrate, for example as a system on a chip integrated circuit, or distributed across devices that are on separate substrates.
  • the processing and control system 105A may include, for example, a single computer processing device (e.g. a central processing unit, graphics processing unit, or other computational device), or may include a plurality of computer processing devices.
  • the processing and control system 105A may also include a communications bus in data communication with one or more machine readable storage (memory) devices which store instructions and/or data for controlling aspects of the operation of the processing unit.
  • the memory devices may include system memory (e.g. a BIOS), volatile memory (e.g. random access memory), and non-volatile memory (e.g. one or more hard disk or solid state drives to provide non-transient storage).
  • the processing and control system 105A includes one or more interfaces, for example interfaces for the control lines C1 to C3 or a control bus, and an interface to receive the signal S2.
  • An external interface may provide an option to update the firmware and/or software of the processing and control system 105A.
  • An external interface may provide an option for a plurality of LiDAR systems to communicate, for example to share information for spatial profiling and/or to share spatial profiles, allowing determinations and actions based on spatial profiling actions of more than one LiDAR system.
  • control operations and the data processing operations are performed by separate physical devices. In other embodiments one or more physical devices may perform both control and data processing operations.
  • the spatial profiling system 100A separates the functional components into two or more physical units.
  • the sensor head 103A may be included in one of the physical units and the light transmitter 101A, light receiver 104A and the processing and control system 105A may be included in one other physical unit, or one or more of these may be in a further physical unit.
  • the sensor head 103A is remote from one or more of the other components.
  • the remote sensor head 103A may be coupled to the other units via one or more guided optical connections, such as waveguides or optical fibres.
  • a spatial profiling system may include multiple sensor heads 103A. Each of the multiple sensor heads 103A may be optically coupled to the light receiver 104A by respective guided optical connections.
  • the multiple sensor heads 103A may be placed at different locations and/or orientated with different fields of view.
  • the light transmitter 101 A and the light receiver 104A are implemented on the same optical sub-assembly. In other embodiments, the light transmitter 101 A and the light receiver 104A are implemented on different optical sub-assemblies.
  • the ADC 107A, and the processing and control system 106A may be implemented on the same printed circuit board assembly or different printed circuit board assemblies, separate from any optical sub-assembly or sub-assemblies.
  • the printed circuit board assembly or assemblies may include or correspond to a system-on-a-chip (SoC) or a system-on-a-module (SoM).
  • SoC system-on-a-chip
  • SoM system-on-a-module
  • FIG 12 illustrates an example arrangement of a light transmitter 201 A, which may for example form the light transmitter 101 A of the spatial profiling system 100A described with reference to Figure 11.
  • the light transmitter 201 A includes a tunable laser 202A, for example a wavelength-tunable laser diode, as a source of a beam of light.
  • the tuned wavelength of the tunable laser 202A may be based on one or more electrical currents, for example the injection current into one of more wavelength tuning elements in a laser cavity, applied to the laser diode.
  • the electrical currents are controlled responsive to a control signal over the control line C1.
  • the light transmitter 201 A accordingly is configured to provide a beam of outgoing light at a selected one or more of multiple selectable wavelength channels (each represented by its respective centre wavelength Xi, X2, ... N).
  • the wavelength range of the wavelength-tunable light source is at least 20 nm, or at least 25 nm, or at least 30 nm, or at least 35 nm.
  • the resolution of the wavelength-tunable light source i.e. smallest wavelength step
  • the wavelength channels are at about 1550 nm or about 1310 nm. Other wavelengths may be used, for example about 905 nm.
  • the light transmitter 201A may select one wavelength channel at a time or may simultaneously provide two or more different selected wavelength channels (i.e. channels with different centre wavelengths).
  • the light from the light source may pass through an optical splitter 203A, where a majority portion of the light is continued along an outgoing light path and the remaining portion of the light is provided as a local oscillator signal.
  • the optical splitter 203A may be a 90/10 fiber-optic coupler, providing 90% of the light as outgoing light and 10% of the light as a local oscillator signal for coherent detection.
  • the optical splitter 203A is omitted.
  • the light transmitter 101A may also include an optical amplifier 204A to amplify (provide gain to) the outgoing light.
  • the optical amplifier 204A is an Erbium-doped fibre amplifier (EDFA) of one or more stages.
  • EDFA Erbium-doped fibre amplifier
  • SOA semiconductor optical amplifier
  • BOA booster optical amplifier
  • solid state amplifier e.g. a Nd:YAG amplifier
  • the gain may be controlled responsive to a control signal over the control line C1.
  • the optical amplifier 204A is omitted.
  • the light transmitter 201 A includes a modulator 205A for imparting a time-varying profile on the outgoing light.
  • This modulation may be in addition to any wavelength tuning as herein before described. In other words, the modulation would be of light at the tuned wavelength.
  • the tuned wavelength may refer to a center frequency or other measure of a wavelength channel that is generated.
  • the time varying profile may, for example, be one or more of a variation in intensity, frequency, phase or code imparted to the outgoing light.
  • the operation of the modulator 205A (e.g. the modulating waveform), may be controlled by the processing and control system 105A by a control signal over the control line C1.
  • the modulator 205A is an external modulator (such as a Mach Zehnder modulator, an electro-optic modulator or an external SOA modulator) to the laser diode.
  • the modulator 205A is a phase modulator.
  • Figure 12 illustrates an example in which the modulator 205A is located after the optical amplifier 204A, it will be appreciated that the modulator may be located either before or after the optical amplifier 204A in the outgoing light path.
  • the modulator of the light transmitter is a semiconductor optical amplifier (SOA) or a Mach Zehnder modulator integrated on a laser diode of the light source.
  • the electrical current applied to the SOA may be varied over time to vary the amplification of the CW light produced by the laser over time, which in turn provide outgoing light with a time-varying intensity profile.
  • the light source instead of including an integrated or external modulator, includes a laser having a gain medium into which an excitation electrical current is controllably injected for imparting a time-varying intensity profile on the outgoing light.
  • a light source, an optical amplifier and a modulator are provided by a sampled-grating distributed Bragg reflector (SG-DBR) laser.
  • the modulator 205A may be controlled to implement, for example, FMCW or RMCW LiDAR.
  • the light transmitter 101 A may include a broadband light source and one or more tunable spectral filters to provide substantially continuous-wave (CW) light intensity at the selected wavelength(s).
  • the light transmitter 101 A includes multiple laser diodes, each wavelength-tunable over a respective range and whose respective outputs are combined to form a single output. The respective outputs may be combined using a wavelength combiner, such as an optical splitter or an arrayed waveguide grating (AWG).
  • a wavelength combiner such as an optical splitter or an arrayed waveguide grating (AWG).
  • the outgoing light may substantially or entirely include one polarisation and substantially or entirely not include the orthogonal polarisation.
  • the outgoing light is only polarised light, but in some embodiments unpolarised light may form a component of the outgoing light.
  • the outgoing light includes at 90%, or at least 95%, or at least 97% or at least 99% or substantially 100A% of light of one polarisation.
  • the outgoing light includes at most 10%, or at most 5%, or at most 3% or at most 1% or substantially no light of one polarisation and a substantial portion of light of the orthogonal polarisation.
  • the substantial portion having the orthogonal polarisation may be at least 50%, or at least 70%, or at least 80% or at least 90% or more.
  • the light transmitter 201 A includes a polariser 206A.
  • the polariser 206A my for example filter the outgoing light into either transverse electric (TE) polarised light or transverse magnetic (TM) polarised light.
  • the light transmitter 101 A or the light transmitter 201 A may be controllable to provide 10 Gbps modulation, may operate across a 35 nm wavelength range and change from one wavelength channel to another in less than 500A nanoseconds, or less than 200A nanoseconds or less than 100A nanoseconds.
  • the wavelength channels may have centre frequencies about 1 GHz or more apart.
  • Figure 13 illustrates an example arrangement of a sensor head 301A, which may for example form the sensor head 103A of the spatial profiling system 100A described with reference to Figure 11.
  • the sensor head 301 A includes an optical circulator 302A and a beam director 303A, which includes a fast-axis beam director, such as a wavelength-based beam director 304A and a slow-axis beam director, such as a mechanical beam director 305A.
  • the fast-axis beam director is configured to direct the beam along a first axis (a “fast axis”) more quickly than the slow- axis beam director is configured to direct the beam along a second axis (a “slow axis”), that is orthogonal or substantially orthogonal to the first axis.
  • the beam director 303A may be downstream of the optical circulator 302A in the outgoing light direction.
  • the optical circulator 302A may be downstream of the beam director 303A in the outgoing light direction.
  • the fast-axis beam director may be downstream of the slow-axis beam director in the outgoing light direction.
  • the fast-axis beam director may be downstream of the slow-axis beam director in the outgoing light direction.
  • the optical circulator 302A is omitted. Separation of the outgoing light (TE in Figure 11) and the incoming light in the original polarisation also TE in Figure 11) may be performed instead by an optical isolator followed by a 2x1 optical coupler (i.e. two input ports and one output port) in the downstream direction, with one of the input ports optically coupled to the optical isolator and the other of the input ports optically coupled to a beam trap (see later herein). Also, as previously described, in some embodiments only wavelength beam direction may be performed by the beam director. Additionally, combined wavelength and mechanical beam direction may be performed, through mechanical movement of a component for wavelengthbased beam direction.
  • the blocks of Figures 1 to 3 represent functional components of the spatial profiling system 100A. Functionality may be provided by distinct or integrated physical components.
  • a light detector may be separate to or integrated with an analogue-to-digital converter (ADC).
  • ADC analogue-to-digital converter
  • the optical circulator 302A (or optical coupler) and wavelength-based beam director 304A may be separate physical components or a single integrated component.
  • Figure 14A shows components of a sensor head, for example the sensor head 301 A of Figure 13, which may form part of the spatial profiling system of Figure 11.
  • the components of Figure 4A are described below in this context.
  • the components include a wavelength router 400A, which in some embodiments forms all or part of the wavelength-based beam director 304A of Figure 13, and an optical circulator 441, which may be the optical circulator 302A of Figure 13.
  • a 2x1 optical coupler may be used instead of an optical circulator.
  • the wavelength router 400A may include or be an arrayed waveguide grating (AWG) or an Echelle grating.
  • AWG arrayed waveguide grating
  • the AWG may be fabricated as an integrated circuit chip, for example, in Si, SiO2 or SiN. Description herein referring to an AWG would be understood by a skilled person in the art to be appliable, without minor modifications, to an Echelle grating.
  • the wavelength router 400A includes an input slab 402A, an output slab 403A and a waveguide array 404A.
  • the terms input and output are used here relative to the outgoing light path P1.
  • the output slab 403A effectively operates as an input slab of the AWG.
  • the waveguide array 404A includes waveguides of different length, to create interference patterns of an AWG.
  • the wavelength router 400A also includes an array of single mode optical fibres 449, distributed across the input slab 402A.
  • An optical fibre 451 of the array of single mode optical fibres 449 forms part of the outgoing light path P1 , and receives outgoing light from the optical circulator 441.
  • the optical circulator 441 receives outgoing light L1 over a light path 453, which may be free-space or guided optical components.
  • the optical fibre 451 is connected to a central location of the input slab 402A.
  • the other optical fibres in the array of single mode optical fibres 449 are placed across the input slab 402A, symmetrically about the optical fibre 451.
  • the outgoing light L1 is from the light source 102A, which is wavelength- tunable, for selectively providing light at a selected one or more of a range of selectable wavelengths Ai to AN.
  • the outgoing light L1 may cycle through each of Ai to AN in order to cover a wavelength dimension.
  • the light source may continuously change wavelength between wavelength channels or may include a step change in wavelength between wavelength channels. Due to the interference in the output slab 403A arising from the waveguide array 404A, different wavelengths exit the output slab 403A at different angles. This difference in angle may be used for beam direction.
  • At least one lens or other suitable optical component is provided in the outgoing light path P1 , downstream of the output slab 403A, for example a collimating lens to collimate the outgoing light and/or a lens to magnify the difference in angle and therefore increase the field of view.
  • an image is formed, the image formed by interfering signals in the input slab 402A.
  • the image may therefore be described as an interference pattern.
  • Such an image or interference pattern is representative of a spatial sample of the surface or the objected from which light is reflected.
  • the target i.e. the part of the environment reflecting the outgoing light
  • the target is spatially sampled, which can be utilised to detect or mitigate speckle effects.
  • the array of single mode optical fibres 449 therefore each provide a return signal R1 to R7.
  • Return signals R-1 to R-7 which decompose or de-construct speckle effects, are referred herein as “despeckled” signals.
  • a plurality of these despeckled signals may be provided to the light receiver 104A for detection, such as coherent detection as discussed above.
  • the light detector 106A may be configured to detect the specularity of the return signal, such as detection of the image or interference pattern related to the speckle. In case of coherent detection, the light detector 106A may be further configured to recover or provide a measure of the amplitude and phase of each despeckled signal.
  • the light detector 106A may be configured to detect specularity based on amplitude and phase of the incoming light in a spatially resolved manner. Whilst the example shows seven fibres, there may be more or less fibres with a corresponding change of more or less receiver channels, ADCs and processing resources. In some embodiments, the light detector 106A is further configured to determine the state of polarization of the return light, such as that of any one or more of the despeckled signals R-1 to R-7. For example, the light detector 106A may include one or more polarizers for each of the despeckled signals R-1 to R-7.
  • Determination of the state of polarization provides an indication of the degree of polarization of the return light, such as how preserved its degree of polarization is upon its reflection from a surface or an object. Further, based on the state of polarization of each of the despeckled signals R-1 to R-7, the degree of polarization of the return light is determined in a spatially resolved manner to facilitate an indication of material characteristics of the surface or object. In particular, the degree of polarization of the return light may be determined relative to the degree of polarization of the outgoing light or the local oscillator.
  • each of despeckled signals R-1 to R-7 is converted to an electrical signal by the optical receiver 104A, which may be converted to a digital signal, for example by ADC 107A. Therefore, the signal S2 of Figure 11 may be viewed as a composite signal, including a signal component corresponding to each of despeckled signals R-1 to R-7. Signal processing, for example by the processing and control system 105A may then combine the digital signals representing the despeckled signals R-1 to R-7, to reduce speckle effects.
  • despeckled signals R-1 to R-7 such as one or more of their spatially resolved amplitude, phase and polarization may be used to characterise or categorise the incoming light L2 and therefore provide at least an input to a characterisation or categorisation of the surface generating the reflected light component of the incoming light L2.
  • the wavelength router 400B is configured to receive outgoing light from multiple outgoing light paths, such as two outgoing light paths 453a and 453b. Each outgoing light path may carry light from the same or different wavelength-tunable light source.
  • the wavelength router 400B is further configured to provide multiple return signals for each of multiple outgoing light paths.
  • Figure 4B like components and features to those described with reference to Figure 4A are shown with like reference numerals.
  • Figure 4B illustrates some parts of the wavelength router and omits other parts of the wavelength router.
  • the waveguide array 404A are shown partially, and components downstream of the waveguide array 404A are omitted.
  • input light from the multiple outgoing light paths 453a and 453b may each be provided to the input slab 402A via, respectively, circulators 441a and 441b and optical fibres 451a and 451b.
  • outgoing light carried by each of the multiple outgoing light paths 453a and 453b propagates through the waveguide array 404A in the outgoing direction.
  • incoming light associated with each of the multiple outgoing light paths 453a and 453b propagates through the waveguide array 404A in the incoming direction.
  • optical fibres 451a and 451b hence the outgoing light paths 453a and 453b, are sufficiently separated such that their associated return signals are received independently.
  • return signals R-1 a to R-7a associated with light path 453a are received independently from return signals R-1 b to R-7b associated with light path 453b.
  • Figure 4B illustrates light from multiple outgoing light paths 453a and 453b propagating in the input slab 402A separately without overlapping in space.
  • light from multiple outgoing light paths 453a and 453b may or may not overlap in space, and may or may not co-propagate along the same one or more waveguides of the waveguide array 404A.
  • the wavelength router 400A is a birefringent wavelength router, for example a birefringent AWG.
  • the birefringent wavelength router is a birefringent diffraction grating, such as a birefringent Echelle grating or birefringent prism.
  • waveguides in the waveguide array 404A may include at least a portion made from a waveguide material of relatively high birefringence.
  • waveguides in the waveguide array 404A may include a waveguide core with a large aspect ratio.
  • the waveguide may include an InP deeply etched ridge with a thin InGaAsP guiding layer.
  • Other forms of birefringent AWG or birefringence compensating AWG may be used.
  • the outgoing light may be polarised, for example due to passing through a polariser.
  • the outgoing light may be transverse electric (TE) polarised light. This polarisation is maintained in the outgoing light, including as it passes through the birefringent AWG and any optical components downstream of the beam director.
  • the outgoing light leaving the LiDAR system is therefore polarised light. Any internal back-reflection will also be polarised.
  • the incoming light which includes outgoing light reflected by the environment, will include a mix of orthogonal polarisation components.
  • TE polarised outgoing light also as shown in Figures 5A and 5B
  • diffused reflection of the outgoing light by the environment will contain both TE and TM polarised light, which may be in roughly equal proportion.
  • Specular reflection of the TE polarised outgoing light will also contain both TE and TM polarised light, with a majority having the original (TE in this example) polarisation.
  • the proportion of the original polarisation may depend on the reflecting material. Reflection from a retroreflector may retain most, for example 99% or more, of the original (TE in this example) polarisation.
  • the outgoing light is TM polarised light
  • diffused reflection of the TM polarised outgoing light by the environment will contain both TE and TM polarised light, which may be in roughly equal proportion.
  • Specular reflection of the TM polarised outgoing light will also contain both TE and TM polarised light, with a majority having the original (TM in this example) polarisation.
  • the proportion of the original polarisation may depend on the reflecting material. Reflection from a retroreflector will retain most, for example 99% or more, of the original (TM in this example) polarisation.
  • the incoming light is passed through the birefringent AWG, in the opposite direction to the outgoing light. Due to the birefringence within the AWG, the different orthogonal polarisation components of the reflected light in the incoming light will back- propagate through the birefringent AWG along the incoming light path, starting from the waveguide array, in different manners.
  • the component of light in the original polarisation e.g. TE in the first example above
  • the component light in the orthogonal polarisation e.g.
  • TM in the first example above will back-propagate through the birefringent AWG along a different path from the outgoing light path, due to the different effective refractive index in the orthogonal axis, and hence different paths lengths experienced by the orthogonally polarised light, and is spatially offset after propagating through the input slab.
  • the spatial offset acquired by the incoming light after propagating through the input slab provides optical isolation of the incoming light from, for example, unwanted light internally reflected by components of the sensor head. That is, the incoming light is isolated or otherwise distinguished from internally back-reflected light based on the spatial offset.
  • the light in the original polarisation therefore propagates back to the circulator. In some embodiments this light is not used to form a signal for distance/range determination of specular or diffuse targets for spatial estimation, at least during some conditions or under all conditions.
  • the light in the original polarisation is not collected by a light receiver. In other words the light is discarded or disregarded.
  • the light is directed to an optically black surface or an otherwise light absorbing or trapping surface.
  • the return signal R-1 of Figure 4 may be directed to a light trap. In other embodiments the light may be discarded to the environment.
  • the light is collected by a light receiver, separate to the light receiver(s) for light in the orthogonal polarisation. That light receiver may be utilised for distance/range determination in the absence of high signal returns, such as from a retroreflector and/or internal back-reflection, and not utilised in the presence of high signal returns. Alternatively, that light receiver may be configured to not be overwhelmed by retroflection and/or internal back-reflection and used for distance/range determination of the retroreflector.
  • the spatial profiling system generates a signal indicative of the presence of a retroreflector in the field of view. One or more actions may be taken in response to that signal, by the spatial profiling system, which actions may be initiated or caused by or performed by the processing and control system 105A, or by a system in communication with the spatial profiling system.
  • At least a portion of the component light in the orthogonal polarisation is collected by a light receiver, for example the light receiver 104A.
  • the collected light in the orthogonal polarisation is used to form at least one signal for distance/range determination for spatial estimation.
  • a plurality of signals are formed, for example based on two or more of return signals R-2 to R-7.
  • the output slab 403A is omitted from the birefringent AWG.
  • the output slab facilitates waveguiding to maintain light propagation along the plane of the output slab. Since the output slab facilitates no dispersion, it can be omitted from the birefringent AWG.
  • the outgoing light from the waveguide array 404A may be passed to another beam director, over guided or free space optics.
  • the outgoing light may be collimated, for example by a collimating lens, prior to or as part of beam direction. Examples of wavelength-based beam directors are described in the incorporated international patent application no. PCT/AU201A6/0508A99.
  • the wavelength-based beam director 304A of Figure 13 may then include a birefringent AWG without an output slab.
  • Figures 15A and 15B each show in part an embodiment of a spatial profiling system 500A.
  • Figure 15A shows components in an outgoing light path, which may for example be the outgoing light path P1 (see Figure 11).
  • Figure 15B shows components in an incoming light path, which may for example be the incoming light path P2 (see Figure 11).
  • TE polarised light is represented by the y direction, which is vertically up/down the page
  • TM polarised light is represented by the x direction, which is into/out of the page.
  • outgoing light is generated by a light transmitter 501 A.
  • the light transmitter 501 A generates polarised outgoing light for spatial estimation of an environment.
  • this is TE polarised light.
  • the polarised outgoing light includes outgoing light at a selected one or more of multiple selectable wavelength channels at respective centre wavelengths Xi, X2, ... XN.
  • all wavelength channels Xi to XN may be individually provided in a predetermined or randomised sequence.
  • the outgoing light passes through an optical circulator 502A.
  • the optical circulator 502A is replaced by a 2x1 coupler or by an optical isolator that passes light traversing the outgoing light path and blocks light traversing the incoming light path.
  • the polarised outgoing light passes through a birefringent AWG 503A, which may for example be the wavelength router 400A (see Figure 14).
  • the birefringent AWG 503A includes an input slab 504A and an output slab 508A.
  • the polarised outgoing light enters the input slab 504A at its first location 506A.
  • the birefringent AWG includes an input slab but lacka an output slab.
  • the output slab 508A facilitates waveguiding to maintain the light propagation in the plane of the output slab 508A (i.e. along the y-z plane in Figure 15).
  • the output slab 508A facilitates no dispersion, hence can be omitted from the birefringent AWG 503A. As explained herein, this may form a wavelength dimension for beam steering.
  • the polarised outgoing light also passes through a second beam director.
  • the second beam director may also direct light based on wavelength, to provide a second wavelength dimension or may direct light based on mechanical movement, to provide a mechanical dimension.
  • the second wavelength dimension or mechanical dimension is orthogonal to, or includes a component orthogonal to the wavelength dimension formed by the birefringent AWG 503A, thereby providing beam direction over two dimensions for 3-dimensional spatial estimation.
  • the second beam director may be omitted, for example where 2- dimensional spatial estimation is required or where the mechanical dimension is provided by movement of the birefringent AWG 503A, for example rotation of the birefringent AWG 503A about a mechanical axis of rotation that is aligned with extends along an optical axis of light exiting the birefringent AWG 503A.
  • incoming light includes reflected outgoing light.
  • the reflected outgoing light includes outgoing light externally reflected by the environment, as well as any outgoing light that is internally reflected by the spatial profiling system and not by the environment.
  • the internally reflected light may be light internally reflected by one or more of the optical components of the spatial profiling system, such as a collimating lens after the birefringent AWG.
  • the externally reflected outgoing light shares at least part of the incoming light path with any internally reflected outgoing light. That is, upon receipt by th birefringent AWG 503A, the externally reflected outgoing light is unisolated from the internally reflected light.
  • the reflected outgoing light includes light of both TE and TM polarisations.
  • the reflected outgoing light also includes light at selected one or more of multiple selectable wavelength channels at respective centre wavelengths Ai, A2, ... AN.
  • the spatial profiling system 500A is coaxial.
  • the incoming light path overlaps the outgoing light path through the beam director and in part through the birefringent AWG 503A.
  • the incoming light is provided to and passes through the waveguides of the birefringent AWG 503A, entering the input slab 504A of the birefringent AWG 503A. Due to the birefringence, the TE and TM polarised light is separated at the input slab 504A of the birefringent AWG 503A.
  • AD L tan (AT>) , where L is the length of the input slab and AT> is the angular offset between the two polarisations.
  • the incoming light of different wavelength channels after propagating through the the birefringent AWG 503A is recombined into the same or substantially same light path. That is, the incoming light of different wavelength channels comprising the original polarisation is provided at the first location 507A at the input slab 504A, spatially offset from incoming light of different wavelength channels comprising the orthogonal polarisation provided at a second location 509A at the input slab 504A.
  • FIG. 16 shows example graphs of the angular separation (left hand graph) and resulting spatial (right hand graph) separation caused by a birefringent AWG, such as the birefringent AWG 503A.
  • the angular separation is sufficient so that a polarisation of one wavelength channel does not spatially overlap with, or is otherwise spatially separate from, the opposite polarisation of another wavelength channel.
  • the highest displacement for TM mode light is for AN, which has a lower displacement than the lowest displacement for TE mode light (for A1).
  • incoming light of the same polarisation (TE) as the outgoing light passes through the optical circulator 502A.
  • This light may traverse a guided optical path, for example an optical fibre, extending between the birefringent AWG 503A and the optical circulator 502A.
  • the optical circulator 502A directs the light to a light trap 505A, for example over another guided optical path such as another optical fibre. Alternatively this light may be discarded or disregarded by other methods, such as directing the light to a suitable location in the environment.
  • Incoming light of different polarisation (TM) is return light for detection.
  • the return light for detection is directed, for example from the second location 509A over a guided optical path, to a light receiver 506A, which may be for example the light receiver 104A.
  • a light receiver 506A which may be for example the light receiver 104A.
  • the capture and detection of a plurality of such return light signals allows for spatial sampling, which in turn allows for the effects of speckle to be mitigated or measured.
  • the output slab of the birefringent AWG 503A is omitted. These embodiments are represented in Figures 5A and 5B by the dashed line boundary of the output slab of the birefringent AWG 503A..
  • the dispersion curves of the TE and TM mode are, except for the angular offset and spatial offset, identical or substantially identical.
  • the design can be influenced to achieve this by the geometry of the waveguide array of the AWG, such as their cross-sectional shape (e.g. rectangular or round), or their longitudinal shape (e.g. tapered).
  • the length (L) of the input slab of the AWG is in the range of 20-200A mm (inclusive).
  • the angular offset is in the range of 0.02-0.03 degrees (inclusive).
  • the spatial offset is in the range of 10-100A pm (inclusive).
  • reception of retroflection by the light receiver 506A is reduced, due to the tendency of retroflection to maintain its original polarisation (e.g. TE mode) and find its way to the light trap 505A.
  • This reduction in reception of retroflection may avoid or reduce the instances in which the light receiver 506A is overwhelmed.
  • the retroreflector may return some orthogonally polarised light (e.g. TM mode), it will typically be at a much lower level and therefore may not overwhelm the light receiver 506A.
  • specular or diffused reflection which contains polarisation orthogonal to the original polarisation (e.g. TM mode) is still received by the light receiver.

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • General Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Radar, Positioning & Navigation (AREA)
  • Remote Sensing (AREA)
  • Optics & Photonics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Optical Integrated Circuits (AREA)

Abstract

L'invention concerne des systèmes et des composants de profilage spatial destinés à être utilisés dans des systèmes de profilage spatial, ainsi que des procédés de profilage spatial. Divers modes de réalisation comprennent un directeur de faisceau et un sous-système optique bidirectionnel, par exemple un circulateur optique, en aval du directeur de faisceau, dans un trajet de lumière sortante. Dans certains modes de réalisation, le directeur de faisceau et le sous-système optique bidirectionnel ou le circulateur optique sont des composants intégrés, par exemple intégrés sur un substrat commun. Des modes de réalisation de composants de dispersion pour un directeur de faisceau optique sont décrits, lesquels comportent une plaque d'entrée et un réseau de guides d'ondes couplé optiquement à la plaque d'entrée. La plaque d'entrée diffracte la lumière sortante, comme dans un réseau sélectif planaire, et le réseau de guides d'ondes a des extrémités à travers la lumière sortante diffractée. Les composants de dispersion peuvent en outre comporter une plaque de sortie ou être dépourvus de celle-ci.
PCT/AU2023/050789 2022-08-22 2023-08-21 Directeur de faisceau optique WO2024040281A1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
AU2022902394 2022-08-22
AU2022902394A AU2022902394A0 (en) 2022-08-22 An optical beam director
AU2022902741 2022-09-21
AU2022902741A AU2022902741A0 (en) 2022-09-21 Spatial profiling systems and methods

Publications (1)

Publication Number Publication Date
WO2024040281A1 true WO2024040281A1 (fr) 2024-02-29

Family

ID=90011951

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/AU2023/050789 WO2024040281A1 (fr) 2022-08-22 2023-08-21 Directeur de faisceau optique

Country Status (1)

Country Link
WO (1) WO2024040281A1 (fr)

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180284237A1 (en) * 2017-03-30 2018-10-04 Luminar Technologies, Inc. Non-Uniform Beam Power Distribution for a Laser Operating in a Vehicle
US20180284284A1 (en) * 2017-03-29 2018-10-04 Luminar Technologies, Inc. Optical resolution in front of a vehicle
US20200249354A1 (en) * 2017-09-26 2020-08-06 Innoviz Technologies Ltd Binning and non-binning combination
US20200333441A1 (en) * 2017-11-01 2020-10-22 Baraja Pty Ltd. Optical circulator
US20220128666A1 (en) * 2019-02-06 2022-04-28 Rockley Photonics Limited Optical components for scanning lidar

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20180284284A1 (en) * 2017-03-29 2018-10-04 Luminar Technologies, Inc. Optical resolution in front of a vehicle
US20180284237A1 (en) * 2017-03-30 2018-10-04 Luminar Technologies, Inc. Non-Uniform Beam Power Distribution for a Laser Operating in a Vehicle
US20200249354A1 (en) * 2017-09-26 2020-08-06 Innoviz Technologies Ltd Binning and non-binning combination
US20200333441A1 (en) * 2017-11-01 2020-10-22 Baraja Pty Ltd. Optical circulator
US20220128666A1 (en) * 2019-02-06 2022-04-28 Rockley Photonics Limited Optical components for scanning lidar

Similar Documents

Publication Publication Date Title
US12038511B2 (en) Precisely controlled chirped diode laser and coherent LIDAR system
US12078759B2 (en) Techniques for spectral scanning in a LIDAR system
US11555923B2 (en) LIDAR system with speckle mitigation
JP7558335B2 (ja) 同時の測距距離および速度測定のための、複数個のレーザおよびコヒーレント受信器の相補的変調に基づくｌｉｄａｒシステム
AU2020203638B2 (en) Spatial profiling system and method
US11709240B2 (en) Descan compensation in scanning LIDAR
US20210316756A1 (en) Device and method for scanning measurement of the distance to an object
US11579294B2 (en) Lidar system with integrated frequency shifter for true doppler detection
KR102628929B1 (ko) 모드 필드 확장기를 갖는 lidar 시스템
KR20210018925A (ko) 광학 빔 지향기
US11733361B2 (en) Polarization encoded beam delivery and collection
US11474206B2 (en) Hybrid optical phase array and MEMS beamsteering for chip-scale Lidar system
CN111077508A (zh) 多光子芯片激光雷达系统架构
US11789154B2 (en) Walk-off compensation in remote imaging systems
JP2022503412A (ja) 光ビーム導波器
WO2024040281A1 (fr) Directeur de faisceau optique
US20240069330A1 (en) Optical beam director
WO2023141672A1 (fr) Systèmes et procédé de profilage spatial
EP4375701A1 (fr) Dispositif de balayage optique dans la mesure de distance avec fmcw lidar
WO2024050594A1 (fr) Systèmes et procédés de profilage spatial

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 23855881

Country of ref document: EP

Kind code of ref document: A1