Grating configuration for optical beam steering

Abstract

The apparatus includes at least one light source port that provides light waves having a tuneable spectral peak wavelength, one or more transmitting optical phased arrays (OPAs) each coupled to the light source port, transmitting OPAs that form beams having a wavelength control angle adjustment range in a first plane and a phase shift control angle adjustment range in a vertical plane, and receiving OPAs each coupled to a coherent receiver, configured to receive received light waves characterized by a wavelength control angle adjustment range in a first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane. The wavelength control angle adjustment ranges of at least two beams are at least partially non-overlapping, and the wavelength control angle adjustment range of each receiving OPA at least partially overlaps with at least one of the wavelength control angle adjustment ranges of the beams.

Description

Technical Field

[0001] Cross - reference to Related Applications This application claims the priority and benefit of U.S. Provisional Application No. 63 / 523,685, entitled "Grating Configuration for Optical Beam Steering," filed on June 28, 2023, the entire disclosure of which is incorporated herein by reference.

[0002] This disclosure relates to a grating configuration for optical beam steering.

Background Art

[0003] Some photonic integrated circuits (PICs) can enable beam steering, for example, by using one or more optical phased arrays (OPAs). Some OPAs have a linear distribution of grating antennas (also referred to as grating elements). Steering centered on a first axis perpendicular to the linear distribution can be provided by changing the relative phase shift within the phase shifters supplied to each grating antenna. This beam steering can be performed in a solid - state manner, rapidly, and potentially with random access, but may be limited to one dimension.

[0004] One application of such beam steering may occur in light detection and ranging (LiDAR) systems. In this system, light waves from a light source are transmitted to a target object at a given distance using an OPA, and light backscattered from the target object may be collected using another OPA. Using various techniques such as modulation and / or time of flight, the distance to the target object can be determined based on information related to the detection event. The light source used in such a system may be a laser or other coherent light source, which provides light waves (also referred to herein simply as "light") having a narrow linewidth and a peak wavelength within a specific range (e.g., about 100 nm to about 1 mm, or its sub-range). Another application in which beam steering may be relevant is free-space optical communications. [Overview of the Initiative]

[0005] In one embodiment, the apparatus generally includes at least one light source port that provides light waves having tuneable spectral peak wavelengths, one or more transmitting optical phased arrays (OPAs) each coupled to the light source port, and a plurality of receiving OPAs each coupled to a coherent receiver coupled to the light source port, each of the one or more transmitting OPAs including a plurality of tuneable optical phase shifters and a plurality of optical grating antennas including two or more optical grating antennas, each of the two or more optical grating antennas coupled to one of the plurality of optical phase shifters, and the one or more transmitting OPAs are configured to form a plurality of beams, each of the plurality of beams having a wavelength control angle adjustment range in a first plane and in a plane perpendicular to the first plane The plurality of receiving OPAs are characterized by a phase shift control angle adjustment range, each receiving OPA comprising a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of the two or more optical grating antennas being coupled to each of the optical phase shifters and configured to receive light waves from a set of receiving angles characterized by a wavelength control angle adjustment range in the first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane, at least two of the wavelength control angle adjustment ranges of the plurality of beams are at least partially non-overlapping, and each of the wavelength control angle adjustment ranges of the plurality of receiving OPAs at least partially overlaps with at least one of the wavelength control angle adjustment ranges of the plurality of beams.

[0006] The embodiment may include one or more of the following features:

[0007] The one or more transmitting OPAs include a plurality of transmitting OPAs, and each of the plurality of transmitting OPAs is configured to form one of the plurality of beams.

[0008] At least one of the one or more transmitting OPAs includes at least one waveguide configured to guide a light wave along a propagation axis, and a plurality of sets of grating elements distributed along the waveguide, wherein the plurality of sets of grating elements are configured to perturb a portion of the light wave as it propagates along the waveguide, emitting a plurality of beams at different angles around an axis perpendicular to the propagation axis, wherein the plurality of sets of grating elements includes a first set of grating elements where adjacent grating elements are separated from each other along the propagation axis by a first length, and a second set of grating elements where adjacent grating elements are separated from each other along the propagation axis by a gap where no grating elements are present, the second set of grating elements being at least twice the first length.

[0009] Each of the aforementioned sets of grating elements is in contact with a strip of material having substantially the same refractive index as the grating element.

[0010] The one or more transmitting OPAs consist of a single transmitting OPA configured to form the plurality of beams.

[0011] Each of the aforementioned sets of grating elements extends along a direction substantially perpendicular to the propagation axis.

[0012] Each of the sets of grating elements includes a first portion positioned to perturb a first portion of the wavefront of the light wave at a first position along the propagation axis, and a second portion positioned to perturb a second portion of the wavefront at a second position along the propagation axis different from the first position, wherein the second portion of the wavefront does not overlap with the first portion of the wavefront at least partially.

[0013] In another embodiment, a method for managing optical phased array beam steering generally involves providing an optical wave having a tuneable spectral peak wavelength from at least one light source port and transmitting a plurality of beams from one or more transmitting optical phased arrays (OPAs) coupled to the light source port, wherein each of the one or more transmitting OPAs includes a plurality of tuneable optical phase shifters and a plurality of optical grating antennas, each including two or more optical grating antennas coupled to each different one of the optical phase shifters, and the one or more transmitting OPAs are configured to form a plurality of beams, each of which has a wavelength control angle adjustment range in a first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane, and providing a coherent receiving The receiving of optical waves to a plurality of receiving OPAs, each coupled to a transmitter, wherein each receiving OPA comprises a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each comprising two or more optical grating antennas coupled to each different one of the optical phase shifters, and each receiving OPA is configured to receive optical waves from a set of receiving angles characterized by a wavelength control angle adjustment range in the first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane, wherein at least two of the wavelength control angle adjustment ranges of the plurality of beams are at least partially non-overlapping, and each of the wavelength control angle adjustment ranges of the plurality of receiving OPAs at least partially overlaps with at least one of the wavelength control angle adjustment ranges of the plurality of beams.

[0014] In another embodiment, the apparatus generally includes at least one waveguide configured to guide a light wave along a propagation axis, and a plurality of sets of grating elements distributed along the waveguide, the plurality of sets of grating elements configured to perturb a portion of the light wave as it propagates along the waveguide, emitting a plurality of beams at different angles around an axis perpendicular to the propagation axis, the plurality of sets of grating elements including a first set of grating elements where adjacent grating elements are separated from each other along the propagation axis by a first length, and a second set of grating elements where adjacent grating elements are separated from each other along the propagation axis by the first length, the second set of grating elements being separated from the first set of grating elements along the propagation axis by a gap where no grating elements are present, the gap being at least twice the size of the first length.

[0015] The embodiment may include one or more of the following features:

[0016] The apparatus further includes at least one light source port that provides light waves having tuneable spectral peak wavelengths, a transmitting optical phased array (OPA) coupled to the light source port, and a plurality of receiving OPAs, each coupled to a coherent receiver coupled to the light source port, wherein the transmitting OPA includes a plurality of tuneable optical phase shifters and a plurality of optical grating antennas, each of the two or more optical grating antennas coupled to a different one of the optical phase shifters, and each of the optical grating antennas includes a structure substantially identical to the waveguide and the plurality of sets of grating elements, and the optical Each grating antenna is configured to form a plurality of beams, each characterized by a wavelength-controlled angle adjustment range in a first plane and a phase-shift-controlled angle adjustment range in a plane perpendicular to the first plane, and each of the plurality of receiving OPAs includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of the two or more optical grating antennas being coupled to each of the optical phase shifters and configured to receive optical waves from a set of receiving angles characterized by a wavelength-controlled angle adjustment range in the first plane and a phase-shift-controlled angle adjustment range in a plane perpendicular to the first plane.

[0017] At least two of the wavelength control angle adjustment ranges of the plurality of beams are at least partially non-overlapping, and the wavelength control angle adjustment range of each of the plurality of receiving OPAs overlaps at least partially with at least one of the wavelength control angle adjustment ranges of the plurality of beams.

[0018] Each of the aforementioned sets of grating elements is in contact with a strip of material having substantially the same refractive index as the grating element.

[0019] Each grating element in the set of the plurality of grating elements includes a first portion positioned to perturb a first portion of the wavefront of the light wave at a first position along the propagation axis, and a second portion positioned to perturb a second portion of the wavefront at a second position along the propagation axis different from the first position, wherein the second portion of the wavefront does not overlap with the first portion of the wavefront at least partially.

[0020] In another embodiment, a method for manufacturing an optical device generally includes forming at least one waveguide configured to guide a light wave along a propagation axis, and forming a plurality of sets of grating elements distributed along the waveguide, wherein the plurality of sets of grating elements are configured to perturb a portion of the light wave as it propagates along the waveguide, emitting a plurality of beams at different angles about an axis perpendicular to the propagation axis, wherein the plurality of sets of grating elements include a first set of grating elements where adjacent grating elements are separated from each other along the propagation axis by a first length, and a second set of grating elements where adjacent grating elements are separated from each other along the propagation axis by a gap where no grating elements are present, which is at least twice the size of the first length.

[0021] In another aspect, generally, the apparatus includes at least one waveguide configured to guide light waves along a propagation axis, and a plurality of grating elements distributed along the waveguide. The plurality of grating elements are configured to perturb a portion of the light waves when the light waves propagate along the waveguide. Each of the plurality of grating elements includes a first portion disposed to perturb a first portion of the wavefront of the light waves at a first position along the propagation axis, and a second portion disposed to perturb a second portion of the wavefront at a second position along the propagation axis different from the first position. The second portion of the wavefront is at least partially non-overlapping with the first portion of the wavefront.

[0022] The aspect may include one or more of the following features.

[0023] Each of the plurality of grating elements includes a first portion that contacts the waveguide at the first position and extends along a direction substantially perpendicular to the propagation axis, and a second portion that contacts the waveguide at the second position and extends along a direction substantially perpendicular to the propagation axis.

[0024] The first portion and the second portion of a particular grating element may be connected to each other.

[0025] The first portion and the second portion of a particular grating element may be connected to each other.

[0026] Each of the plurality of grating elements may include a first portion that contacts the waveguide at a third position and extends at least to the first position, and a second portion that contacts the waveguide at the third position and extends at least to the second position.

[0027] The particular grating element extends along a substantial straight line that forms an angle not perpendicular to the propagation axis.

[0028] The apparatus further includes at least one light source port that provides light waves having tuneable spectral peak wavelengths, a plurality of transmitting optical phased arrays (OPAs) each coupled to the light source port, and a plurality of receiving OPAs each coupled to a coherent receiver coupled to the light source port, each transmitting OPA of the plurality of transmitting OPAs including a plurality of tuneable optical phase shifters and a plurality of optical grating antennas including two or more optical grating antennas, each of the two or more optical grating antennas coupled to each different of the optical phase shifters, and each of the optical grating antennas including a structure substantially identical to the waveguide and the plurality of grating elements, wavelength control in a first plane The receiving OPA is configured to form a beam characterized by a wavelength control angle adjustment range and a phase shift control angle adjustment range in a plane perpendicular to the first plane, and each of the plurality of receiving OPAs includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of the two or more optical grating antennas being coupled to each different of the optical phase shifters, and each of the optical grating antennas including a structure substantially identical to the waveguide and the plurality of grating elements, and is configured to receive optical waves from a set of receiving angles characterized by a wavelength control angle adjustment range in the first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane.

[0029] At least two of the wavelength control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a wavelength control angle adjustment range that at least partially overlaps with the wavelength control angle adjustment range of at least one beam of the plurality of transmitting OPAs, or at least two of the phase shift control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a phase shift control angle adjustment range that at least partially overlaps with the phase shift control angle adjustment range of at least one beam of the plurality of transmitting OPAs.

[0030] In another aspect, generally, a method of manufacturing an optical device includes forming at least one waveguide configured to guide light waves along a propagation axis, and forming a plurality of grating elements distributed along the waveguide, wherein the plurality of grating elements are configured to perturb a portion of the light waves as the light waves propagate along the waveguide, and each of the plurality of grating elements includes a first portion arranged to perturb a first portion of the wavefront of the light waves at a first position along the propagation axis, and a second portion arranged to perturb a second portion of the wavefront at a second position along the propagation axis different from the first position, and the second portion of the wavefront is at least partially non-overlapping with the first portion of the wavefront.

[0031] In another embodiment, the apparatus generally includes at least one light source port that provides light waves having tuneable spectral peak wavelengths, a plurality of transmitting optical phased arrays (OPAs) each coupled to the light source port, and a plurality of receiving OPAs each coupled to a coherent receiver coupled to the light source port, each transmitting OPA of the plurality of transmitting OPAs including a plurality of tuneable optical phase shifters and a plurality of optical grating antennas including two or more optical grating antennas, each of the two or more optical grating antennas being coupled to one different of the optical phase shifters and configured to form a beam characterized by a wavelength control angle adjustment range in a first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane, each receiving OPA of the plurality of receiving OPAs including a plurality of tuneable optical phase shifters and a plurality of optical grating antennas including two or more optical grating antennas, Each optical grating antenna is coupled to one of the different optical phase shifters and configured to receive optical waves from a set of receiving angles characterized by a wavelength control angle adjustment range in the first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane, wherein at least two of the wavelength control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a wavelength control angle adjustment range that at least partially overlaps with the wavelength control angle adjustment range of at least one beam of the plurality of transmitting OPAs, or at least two of the phase shift control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a phase shift control angle adjustment range that at least partially overlaps with the phase shift control angle adjustment range of at least one beam of the plurality of transmitting OPAs.

[0032] The embodiment may include one or more of the following features:

[0033] At least two of the wavelength control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a wavelength control angle adjustment range that at least partially overlaps with the wavelength control angle adjustment range of at least one beam of the plurality of transmitting OPAs.

[0034] At least two of the phase shift control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a phase shift control angle adjustment range that at least partially overlaps with the phase shift control angle adjustment range of at least one beam of the plurality of transmitting OPAs.

[0035] At least two of the wavelength control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a wavelength control angle adjustment range that at least partially overlaps with the wavelength control angle adjustment range of at least one beam of the plurality of transmitting OPAs, and at least two of the phase shift control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a phase shift control angle adjustment range that at least partially overlaps with the phase shift control angle adjustment range of at least one beam of the plurality of transmitting OPAs.

[0036] At least one of the plurality of transmitting OPAs includes at least one waveguide configured to guide a light wave along a propagation axis, and a plurality of sets of grating elements distributed along the waveguide, wherein the plurality of sets of grating elements are configured to perturb a portion of the light wave as it propagates along the waveguide, emitting a plurality of beams at different angles around an axis perpendicular to the propagation axis, wherein the plurality of sets of grating elements includes a first set of grating elements where adjacent grating elements are separated from each other along the propagation axis by a first length, and a second set of grating elements where adjacent grating elements are separated from each other along the propagation axis by a gap where no grating elements are present, which is at least twice the size of the first length.

[0037] Each of the aforementioned sets of grating elements is in contact with a strip of material having substantially the same refractive index as the grating element.

[0038] At least one of the plurality of transmitting OPAs includes at least one waveguide configured to guide a light wave along a propagation axis, and a plurality of grating elements distributed along the waveguide, wherein the plurality of grating elements are configured to perturb a portion of the light wave as it propagates along the waveguide, emitting a plurality of beams at different angles around an axis perpendicular to the propagation axis, and the plurality of grating elements include a first portion positioned to perturb a first portion of the wavefront of the light wave at a first position along the propagation axis, and a second portion positioned to perturb a second portion of the wavefront at a second position along the propagation axis different from the first position, wherein the second portion of the wavefront is at least partially non-overlapping with the first portion of the wavefront.

[0039] The first and second parts of a particular grating element may be connected to each other.

[0040] In another embodiment, a method for managing optical phased array beam steering generally includes transmitting an optical wave having a tuneable spectral peak wavelength from at least one light source port, transmitting a beam from a plurality of transmitting optical phased arrays (OPAs), each coupled to the light source port, each transmitting OPA comprising a plurality of tuneable optical phase shifters and a plurality of optical grating antennas, each of which is coupled to a different one of the optical phase shifters, and receiving the optical wave to a plurality of receiving OPAs, each coupled to a coherent receiver coupled to the light source port, each receiving OPA comprising a plurality of tuneable optical phase shifters and a plurality of optical grating antennas, each of which is configured to form a beam characterized by a wavelength control angle adjustment range in a first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane, and receiving the optical wave to a plurality of receiving OPAs, each coupled to a coherent receiver coupled to the light source port, each receiving OPA comprising a plurality of tuneable optical phase shifters and a plurality of optical grating antennas The present invention includes a plurality of optical grating antennas, each of which is coupled to a different optical phase shifter and configured to receive light waves from a set of receiving angles characterized by a wavelength control angle adjustment range in the first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane, wherein at least two of the wavelength control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a wavelength control angle adjustment range that at least partially overlaps with the wavelength control angle adjustment range of at least one beam of the plurality of transmitting OPAs, or at least two of the phase shift control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a phase shift control angle adjustment range that at least partially overlaps with the phase shift control angle adjustment range of at least one beam of the plurality of transmitting OPAs.

[0041] Multiple embodiments may have one or more of the following advantages.

[0042] The optical methods and systems disclosed herein can be used to emit or receive optical beams over a wide range of angles (i.e., a large field of view), or to probe and measure environments or areas. The grating arrangements disclosed herein allow for the addition of angular offsets along two dimensions of beam steering (wavelength-controlled angular adjustment range and phase-shift-controlled angular adjustment range). Such angular offsets allow for the coverage of a wide range of angles for optical transceivers incorporating multiple optical phased arrays. Some grating arrangements allow for the transmission of multiple beams by a single optical phased array, reducing complexity, power consumption, size, and weight where possible.

[0043] Other features and advantages will become apparent from the following description, as well as from the drawings and claims. [Brief explanation of the drawing]

[0044] This disclosure is best understood in conjunction with the attached drawings, as detailed below. It is emphasized that, by common practice, various features of the drawings are not to scale. Conversely, dimensions of various features have been arbitrarily enlarged or reduced for clarity.

[0045] [Figure 1] This is a schematic diagram of an exemplary optical phased array. [Figure 2] This is a schematic diagram of an example optical transceiver system. [Figure 3A] This is a schematic diagram of an example optical transceiver system. [Figure 3B] This is a schematic diagram of an example optical transceiver system. [Figure 3C] This is a schematic diagram of an example optical transceiver system. [Figure 3D]This is a schematic diagram of an exemplary optical transceiver system and an exemplary field of view of each optical phased array within the transceiver. [Figure 3E] This is a schematic diagram of an exemplary optical transceiver system and an exemplary field of view of each optical phased array within the transceiver. [Figure 3F] This is a schematic diagram of an example optical transceiver system. [Figure 3G] This is a schematic diagram of an example optical transceiver system. [Figure 4A] This is a schematic diagram of an exemplary optical phased array. [Figure 4B] This is a schematic diagram of an exemplary grating antenna. [Figure 4C] Predictive plots of the square of the far-field electric field as a function of emission angle in four exemplary optical phased arrays. [Figure 4D] This is a schematic diagram of an exemplary grating antenna. [Figure 4E] This is a predicted plot of the square of the far-field electric field as a function of the emission angle for an exemplary grating antenna. [Figure 4F] This is a schematic diagram of an exemplary grating antenna. [Figure 4G] This is a predicted plot of the square of the far-field electric field as a function of the emission angle for an exemplary grating antenna. [Figure 4H] This is a schematic diagram of an exemplary grating antenna. [Figure 4I] This is a schematic diagram illustrating an example of a grating antenna configuration. [Figure 5A] Predicted plots of light intensity as a function of angle in air for three corresponding exemplary grating antennas, and schematic diagrams of the corresponding exemplary grating antennas. [Figure 5B] This is a schematic diagram of an exemplary grating antenna. [Figure 5C] This is a schematic diagram of an exemplary grating antenna. [Figure 5D]This is a schematic diagram of an exemplary grating antenna. [Figure 6A] This is a schematic diagram of an exemplary grating antenna and a corresponding predictive plot of an exemplary far-field radiation pattern. [Figure 6B] This is a schematic diagram of an exemplary grating antenna and a corresponding predictive plot of an exemplary far-field radiation pattern. [Figure 6C] This is a schematic diagram illustrating an example of a grating antenna configuration. [Figure 6D] This is a schematic diagram illustrating an example of a grating antenna configuration. [Figure 7A] This is a schematic diagram of an exemplary grating antenna. [Figure 7B] This is a schematic diagram illustrating an example of a grating antenna configuration. [Modes for carrying out the invention]

[0046] Photonic integrated circuits (PICs) can enable beam steering, for example, by using optical phased arrays (OPAs). However, two-dimensional solid-state beam steering can be difficult in PIC-only architectures. In some examples, a second dimension of beam steering can be accessed by combining wavelength tuning with a grating-based antenna as an array of antennas within the OPA. For example, the grating-based antenna may be an optical grating antenna (or simply referred to herein as a “grating antenna”). This grating antenna comprises a waveguide and grating elements distributed over at least a portion of the waveguide to perturb the light waves propagating through the waveguide, as will be described in more detail below.

[0047] This specification discloses technologies and devices including 2D beam steering. In some examples, the disclosed technologies and devices can perform 2D beam steering, enabling light emitted from one or more optical phased arrays to individually or collectively cover an entire hemispherical volume. In other examples, 2D beam steering may cover a volume that is part of the entire hemispherical volume. For example, 2D beam steering may cover a conical volume, or a portion of the entire hemispherical volume obtained by removing a spherical cone volume from the hemisphere. Furthermore, 2D beam steering may cover a portion of a spherical cone volume obtained by removing a smaller spherical cone volume from the spherical cone volume. A spherical cone (also called a spherical sector) is a portion of a sphere defined by a conical boundary having its vertex (i.e., a point of the spherical cone) at the center of the sphere. A spherical cone is the union of a spherical cap and a cone formed by the center of the sphere and the base of the spherical cap. The disclosed technologies and devices allow for an increased field of view accessible to light emitted from or received from an optical phased array.

[0048] Some examples described herein include optical phased arrays comprising a receiving aperture (i.e., a receiving optical phased array, a receiving unit, or a receiving subsystem) and a transmitting aperture (i.e., a transmitting optical phased array, a transmitting unit, or a transmitting subsystem). Some examples may include separate structures (e.g., in a bistatic arrangement) where the transmitting aperture and the receiving aperture are not physically connected to each other or are manufactured as standalone devices. In some examples, the transmitting aperture and the receiving aperture may be identical (e.g., in a monostatic arrangement).

[0049] In this specification, the angle range may include both a wavelength-controlled angle adjustment range in a first plane and a phase-shift-controlled angle adjustment range in a plane perpendicular to the first plane.

[0050] Figure 1 shows an exemplary optical phased array 100 including an array of grating antennas 102. Light can be transmitted from or received by entering into a plurality of grating elements (not shown) distributed along the line in which the grating antennas are positioned. The optical phased array 100 further includes an array of phase shifters 104, which may be, for example, thermal phase shifters, electro-optic phase shifters, and / or micro-electromechanical phase shifters. In some examples, each phase shifter 104 may be controlled independently, and in other examples, two or more of the phase shifters 104 may be controlled jointly. The phase shifters 104 can modulate the directional and radiant intensity patterns (i.e., gain patterns) associated with one or more beams transmitted from or received from the optical phased array 100. An optical power splitter 106 optically couples its optical port 108 to each phase shifter 104, and the phase shifters 104 are optically coupled to their respective grating antennas 102. In this example, the power splitter 106 is connected by waveguides in a binary tree configuration, but generally, a non-binary tree configuration may be used. Thus, the optical wave received by the grating antenna 102 is merged with the output optical wave at the optical port 108 and can then be further manipulated, converted, or measured. In the reverse direction, the input optical wave given at the optical port 108 can be coupled to the grating antenna 102 via a grating element (e.g., a grating coupler) and transmitted.

[0051] In some implementations, the examples described herein may be designed to operate over a determined optical wavelength range, for example, a band of λ = 1500 to 1600 nm or a band of λ = 1270 to 1330 nm, and the fundamental spacing pitch a between grating antennas may be as large as the optical wavelength. For example, for operation in the 1500 to 1600 nm band, 700 nm ≤ a ≤ 4000 nm may be typical.

[0052] Figure 2 shows an exemplary optical transceiver system 200 comprising a radiant intensity pattern 201 associated with a transmitter optical phased array 202 and a receiver optical phased array 204. The transmitter main lobe 206 and the receiver main lobe 208 overlap. Such overlapping lobe arrangement can result, for example, from tuning phase shifters associated with the transmitter grating antenna and the receiver grating antenna in the optical phased array. Generally, one or more optical beams emitted or received from an optical phased array in a transceiver system can be steered using, for example, reflection, dispersion, and / or refraction structures. Return signals from objects located near the main lobes are received by the receiver optical phased array 204.

[0053] Figure 3A shows an exemplary optical transceiver system 300A that includes both a transmit (TX) optical phased array and a receive (RX) optical phased array. These optical phased arrays are configured to transmit or receive light over a certain range of tunable angles (by using wavelength-controlled angle adjustment ranges corresponding to a certain range of wavelengths over which the light waves received from a coherent light source, such as a tunable laser, are tuned). In this example, there are four pairs of TX and RX optical phased arrays. Within each pair, the TX and RX optical phased arrays each have substantially similar ranges of tunable transmit or receive angles for beam steering. The four pairs of TX and RX optical phased arrays are: (1) the first TX optical phased array 302A and the first RX optical phased array 304A, each having a first angular range 301A; (2) the second TX optical phased array 302B and the second RX optical phased array 304B, each having a second angular range 301B; (3) the third TX optical phased array 302C and the third RX optical phased array 304C, each having a third angular range 301C; and (4) the fourth TX optical phased array 302D and the fourth RX optical phased array 304D, each having a fourth angular range 301D. In some examples, different fields of view (e.g., corresponding to the steering range of the transmitted beam or to the angles of different sets of received beams) are at least partially non-overlapping. For example, each angular range associated with the OPA covers its respective field of view, thereby allowing the four pairs of TX and RX optical phased arrays to transmit and receive light over a collectively larger field of view. In some examples, the fields of view may have a small overlap so that the collective field of view is substantially increased compared to a single field of view from one optical phased array. In other examples, the fields of view may have substantial overlap (e.g., to allow for detection redundancy or depending on the application). It is understood that the light transmitted or received by the optical phased array may have an angular intensity profile with a small but non-zero tail.In this specification, partially overlapping fields of view are directed to two or more fields of view in which portions of their respective intensity profiles (not present in the (possibly rapidly attenuating) tails of those intensity profiles) overlap. In this example, the angular range associated with each optical phased array is offset with respect to at least one other optical phased array in the optical transceiver system 300A (this is done, for example, by using grating elements of different pitches, as shown in Figure 3B). While this angular offset relates to the wavelength-controlled angular adjustment range in the first plane, the phase-shift controlled angular adjustment range allows for additional tuning possibilities in a plane orthogonal to the first plane.

[0054] Figure 3B shows an exemplary optical transceiver system 300B, which includes both a TX optical phased array and an RX optical phased array on a photonic chip 310, configured to transmit and / or receive light over a tunable angular range. In this example, there are four pairs of TX and RX optical phased arrays. Within each pair, the TX and RX optical phased arrays each have a substantially similar constant transmit or receive angular range for beam steering, partly due to each TX and RX pair having substantially similar pitches Λ. The four pairs of TX and RX optical phased arrays are: (1) the first TX optical phased array 312A and the first RX optical phased array 314A, each having a pitch Λ4; (2) the second TX optical phased array 312B and the second RX optical phased array 314B, each having a pitch Λ3; (3) the third TX optical phased array 312C and the third RX optical phased array 314C, each having a pitch Λ2; and (4) the fourth TX optical phased array 312D and the fourth RX optical phased array 314D, each having a pitch Λ1. The first TX optical phased array 312A, the second TX optical phased array 312B, the third TX optical phased array 312C, and the fourth TX optical phased array 312D are each optically coupled to the light source port 318 via an optical splitter 316. As a result, the light source port 318 provides an optical wave that may have a tuneable spectral peak wavelength. The optical splitter 316 can selectively allow optical coupling between the light source port 318 and the TX optical phased array (for example, sequentially connecting only one TX optical phased array at a time, or connecting all four TX optical phased arrays to the light source port 318). The optical wave may be generated on the photonic chip 310 or optically coupled on the photonic chip 310. The first RX optical phased array 314A, the second RX optical phased array 314B, the third RX optical phased array 314C, and the fourth RX optical phased array 314D are each optically coupled to the corresponding IQ detector 320. Each IQ detector 320 is optically coupled to the corresponding LO signal 322 (local oscillator signal).In this example, the LO signal 322 is also derived from the light wave provided at the light source port 318. The IQ detector 320 is an example of a coherent receiver that generates in-phase and quadrature-phase signals. Other examples of coherent receivers include balance detectors. Within a coherent receiver, two light waves are coherently mixed. One of these light waves may be a local oscillator (LO), and the other light wave may be a received optical signal (e.g., from a first RX optical phased array 314A) that can be backscattered (e.g., in LiDAR applications). The LO signal and the RX signal may be substantially the same mode so as to be coherently mixed. A particular mode of the light wave corresponds to a particular spatial mode and a particular temporal mode. The spatial mode may have a particular intensity distribution across a cross-sectional plane perpendicular to the propagation axis of the light wave. The temporal mode may depend on the reference used. For example, a particular time mode may be based on a particular longitudinal mode (having a particular wavelength) oscillating within the laser system in continuous-wave operation, or on a particular time envelope oscillating within the laser system in pulsed operation (e.g., in a mode-locked laser). Thus, a laser system (not shown) may be configured and calibrated to produce a single-mode output used in such a coherent receiver. As a result, both the LO signal 322 (as an optical wave) and the transmit optical wave (e.g., in a LiDAR or communications application) at the light source port 318 are provided, the transmit optical wave is then transmitted by one or more TX optical phased arrays and subsequently received by one or more RX optical phased arrays.

[0055] Figure 3C shows an exemplary optical transceiver system 300C that includes both TX and RX optical phased arrays configured to transmit or receive light over tunable angular ranges. This example includes one TX optical phased array 322 and four RX optical phased arrays. The TX optical phased array 322 has four beams (i.e., multimodal emission), each beam having its own tunable range from which it can transmit light, namely the first angular range 321A, the second angular range 321B, the third angular range 321C, and the fourth angular range 321D. The first RX optical phased array 324A is configured to receive light over a first angular range 321A, the second RX optical phased array 324B is configured to receive light over a second angular range 321B, the third RX optical phased array 324C is configured to receive light over a third angular range 321C, and the fourth RX optical phased array 324D is configured to receive light over a fourth angular range 321D. Thus, while the TX optical phased array 322 is configured to emit light over four angular ranges, each of the four RX optical phased arrays is configured to receive light over a single angular range that substantially overlaps with at least one of the four angular ranges of the TX optical phased array 322. In some applications, the four angular ranges of the TX optical phased array 322 may not substantially overlap with one or more of the ranges of the four RX optical phased arrays. In some examples, RX optical phased arrays with multiple beam reception may be used, similar to the TX optical phased array 322. However, for such optical transceivers, it can be difficult to distinguish which of multiple beams is being received by such an RX optical phased array. In such cases, the RX optical phased array shown in Figure 3C may allow for the distinction between multiple beams by having a receiving angle that substantially overlaps with only one beam from the TX optical phased array 322.

[0056] Figure 3D shows an exemplary optical transceiver system 300D having an exemplary field of view (FOV). This example includes one TX optical phased array 332 and four RX optical phased arrays, each optical phased array coupled to a corresponding port. The TX optical phased array 332 receives transmitted light from the transmitter port 338 (coupled to a light source port, not shown), and the RX optical phased arrays provide the received light at their respective receiver ports 339. Each of the four RX optical phased arrays has an FOV corresponding to a certain angular range (for example, the angular range of angles θ1 for the first RX optical phased array 334A). The TX optical phased array 332 has four angular ranges. Each of the four angular ranges relates to a corresponding light beam emitted by the TX optical phased array 332. For example, one light beam emitted by the TX optical phased array 332 may have an angular range of θ1, a second light beam may have an angular range of θ2, a third light beam may have an angular range of θ3, and a fourth light beam may have an angular range of θ4. The angular ranges θ1 to θ4 may be larger or smaller than those shown in this example, and additional or fewer light beams may be emitted by the TX optical phased array 332.

[0057] Figure 3E shows an exemplary optical transceiver system 300E having an exemplary field of view (FOV). This example includes a first TX optical phased array 342A, a second TX optical phased array 342B, and four RX optical phased arrays, each optical phased array coupled to a corresponding port. The TX optical phased arrays receive transmitted light from their respective transmitter ports 348 (coupled to light source ports, not shown), and the RX optical phased arrays provide the received light at their respective receiver ports 349. Each of the four RX optical phased arrays has an FOV corresponding to a certain angular range (e.g., the angular range θ1 for the first RX optical phased array 344A). The first TX optical phased array 342A has two angular ranges, each corresponding to a corresponding light beam emitted by the first TX optical phased array 342A. For example, one optical beam emitted by the first TX optical phased array 342A may have an angular range of θ1, and a second optical beam may have an angular range of θ3. The second TX optical phased array 342B also has two angular ranges. Each of the two angular ranges relates to a corresponding optical beam emitted by the second TX optical phased array 342B. For example, one optical beam emitted by the second TX optical phased array 342B may have an angular range of θ2, and a second optical beam may have an angular range of θ4. The angular ranges θ1 to θ4 may be larger or smaller than those shown in this example, and additional or fewer optical beams may be emitted by the first TX optical phased array 342A or the second TX optical phased array 342B.

[0058] Figure 3F shows an exemplary optical transceiver system 300F. A first TX optical phased array 352A is configured to transmit light over a first angular range 351A, and a first RX optical phased array 354A is configured to receive light over the first angular range 351A. Similarly, a second TX optical phased array 352B is configured to transmit light over a second angular range 351B, and a second RX optical phased array 354B is configured to receive light over the second angular range 351B. In this example, the angular range associated with each optical phased array is offset with respect to at least one other optical phased array in the optical transceiver system 300F (this is achieved, for example, by using grating elements arranged in two columns of the same pitch but offset from each other, as shown in Figures 5A-5D). This angular offset relates to the phase shift control angular adjustment range in a second plane, which corresponds to the range of phase shifts imposed using the OPA's phase shifter, while the wavelength control angular adjustment range allows for additional tuning possibilities for beam steering orthogonal to the second plane.

[0059] In general, optical transceiver systems may be designed to selectively incorporate elements from the optical transceiver systems shown in Figures 3A, 3C, and 3E. For example, angular offsets related to both wavelength-controlled and phase-shift-controlled angular adjustment ranges may allow for a wider field of view for optical transceiver systems that include optical phased arrays having one or more such angular offsets.

[0060] Figure 3G shows an exemplary optical transceiver system 300G, which includes both a TX optical phased array and an RX optical phased array configured to transmit or receive light over a tuneable angular range. The first TX optical phased array 362 transmits four beams (i.e., multimodal emission), each having a corresponding tuneable range. Collectively, the four beams of the first TX optical phased array 362 can transmit light over a first collective angular range 370, which includes a first angular range 370A, a second angular range 370B, a third angular range 370C, and a fourth angular range 370D. The first RX optical phased array 364A is configured to receive light over a first angular range 370A, the second RX optical phased array 364B is configured to receive light over a second angular range 370B, the third RX optical phased array 364C is configured to receive light over a third angular range 370C, and the fourth RX optical phased array 364D is configured to receive light over a fourth angular range 370D. The second TX optical phased array 366 transmits four beams (i.e., multimodal emission), each having a corresponding tunable range. Collectively, the four beams of the second TX optical phased array 366 can transmit light over a second collective angular range 372, including a fifth angular range 372A, a sixth angular range 372B, a seventh angular range 372C, and an eighth angular range 372D. The fifth RX optical phased array 368A is configured to receive light over a fifth angular range 372A, the sixth RX optical phased array 368B is configured to receive light over a sixth angular range 372B, the seventh RX optical phased array 368C is configured to receive light over a seventh angular range 372C, and the eighth RX optical phased array 368D is configured to receive light over an eighth angular range 372D. In this example, the angular range associated with each optical phased array is offset with respect to at least one other optical phased array in the optical transceiver system 300G.

[0061] Figure 4A shows an OPA 400A (Optical Phased Array) including a number of grating antennas 402 capable of transmitting and receiving light. Each grating antenna includes a waveguide 404 and grating elements 406 arranged periodically at a constant pitch (i.e., constant spacing between grating elements 406). The solid angle range in which the OPA 400A can transmit and receive light can be modified with respect to two orthogonal directions: (1) a wavelength-controlled angle adjustment range that steers around the y-axis and allows scanning along the x-axis, and (2) a phase-shift controlled angle adjustment range that steers around the x-axis and allows scanning along the y-axis. Wavelength-controlled steering can be performed by modifying the wavelength of light transmitted or received by the OPA 400A, and phase-shift controlled steering can be performed by changing the relative phase shift between different grating antennas 402.

[0062] Figure 4B shows a grating antenna 400B including a waveguide 420 and grating elements 422 (e.g., grating couplers) periodically arranged according to a unit cell 424 having a constant grating element pitch (i.e., a constant spacing between grating elements 422) that can be on the order of the wavelength λ of light. A grating element pitch of less than λ / 2 results in a single tuneable beam of light being transmitted or received by an optical phased array (not shown) including such a grating antenna.

[0063] Figure 4C shows predicted plots of the square of the far-field electric field as a function of emission angle for four exemplary RX optical phased arrays having different grating element pitches associated with the grating antenna. As the grating element pitch changes between 0.5 and 0.636 μm, the emission angle associated with the peak in the square of the far-field electric field changes accordingly. Therefore, by incorporating optical phased arrays with different grating element pitches into an optical transceiver, the optical transceiver can transmit and receive light over a wider angular range, as shown in Figures 3A, 3B, 3C, and 3D.

[0064] Figure 4D shows an exemplary grating antenna 400D that includes a waveguide 430 and grating elements 432 periodically arranged according to a unit cell 434 having a non-constant grating element pitch (i.e., a non-constant spacing between grating elements 432 within a unit cell compared to grating elements 432 within adjacent unit cells). In this example, the grating elements 432 within a unit cell 434 are separated by a distance 436 on the order of the wavelength of light λ. The distance 438 between the last grating element in a unit cell and the first grating element in a subsequent unit cell can be much larger than the grating distance 436, such that each unit cell 434 has a length of 7 μm. By designing the grating elements 432 in such a configuration, the grating antenna 400D can transmit and receive multiple light beams at different angles, as shown in Figure 4E. In general, the length of a unit cell can vary depending on the application. In some examples, the length of a unit cell is substantially greater than the wavelength of light being transmitted or received. The length of a unit cell 434 determines the number of beams appearing in the array factor, and the arrangement of perturbations within the unit cell 434 (e.g., grating elements 432) determines the overall envelope (i.e., element factor) that sets the relative intensities of the different beams. Generally, the beam spacing can be inversely proportional to the unit cell spacing, so a longer unit cell length results in an array factor with more beams. Additional modifications within each unit cell 434 (e.g., shorter or longer arrangements of grating elements, resulting in fewer or more grating elements) result in a wider or narrower element factor based on the resulting intensity shaping (i.e., envelope) applied to (i.e., multiplied by) those beams. Other modifications within and / or between unit cells can achieve different beam characteristics, such as different relative intensities of different beams.

[0065] Figure 4E shows a predicted plot of the square of the far-field electric field as a function of emission angle for an exemplary grating antenna with a non-constant grating element pitch (e.g., grating antenna 400D in Figure 4D). The multiple peaks in the far-field electric field indicate that at least eight light beams at different emission angles can be transmitted and received by such a grating antenna. The shown peaks may be further tuned by correcting the wavelength of the transmitted or received light.

[0066] Figure 4F shows an exemplary grating antenna 400F, which includes a waveguide 440 and grating elements 442 periodically arranged according to unit cells 444 having a non-constant grating element pitch (i.e., non-constant spacing between grating elements 442 within a unit cell compared to grating elements 442 within adjacent unit cells). In this example, some grating elements 442 are separated by a distance on the order of the wavelength λ of light, while some grating elements 442 are separated by a larger distance. For example, in this example, each unit cell has a length of 7 μm. By arranging the grating elements 442 in such a configuration, the grating antenna 400F can emit and receive multiple light beams at different angles. Compared to the grating antenna 400D in Figure 4D, the grating antenna 400F in Figure 4F has fewer grating elements 442 per unit cell 444.

[0067] Figure 4G shows a predicted plot of the square of the far-field electric field as a function of emission angle for an exemplary grating antenna with a non-constant grating element pitch (e.g., grating antenna 400F in Figure 4F). The multiple peaks in the far-field electric field indicate that at least eight light beams at different emission angles can be transmitted or received by such a grating antenna. Both Figures 4G and 4E show predicted plots for a grating antenna with a unit cell length of 7 μm, and therefore they both show the same number of emitted beams (i.e., eight peaks in the far-field electric field). However, the grating antenna corresponding to Figure 4G contains less perturbation within each unit cell, resulting in a wider element factor (i.e., envelope) applied to (i.e., multiplied by) those eight beams.

[0068] Figure 4H shows an exemplary grating antenna 400H, which includes a waveguide 450 and grating elements 452 periodically arranged according to a unit cell 454 having a non-constant grating element pitch (i.e., non-constant spacing between grating elements 452 within a unit cell compared to grating elements 452 within adjacent unit cells). In this example, the grating elements 452 are interconnected by strips 456. The strips 456 are made from the same material as the grating elements 452 (e.g., silicon nitride) and are parallel to the propagation axis of the waveguide 450. In other examples, the strips 456 may be made of a different material but may have substantially the same refractive index as the grating elements 452. Including such strips can simplify the manufacturing of the grating antenna. Furthermore, the strips 456 can be designed so that the range of angles from which light is emitted from the TX optical phased array containing a number of grating antennas 400H better matches the range of angles from which light is received from the RX optical phased array containing grating antennas with a constant subwavelength pitch between the grating antennas. A mismatch in refractive indices between the TX and RX optical phased arrays can result in non-matching angular ranges. For example, a grating antenna with separation greater than wavelength between grating elements and without strips (e.g., 400F in Figure 4F) may have substantially different refractive indices than an RX optical phased array that includes grating antennas with a constant subwavelength pitch between them. This difference in refractive index can arise from differences in the amount of grating material (e.g., silicon nitride) on the waveguide surface. Therefore, by incorporating strip 456, the refractive index on the surface of waveguide 450 can be designed to better match that of the RX optical phased array.

[0069] Figure 4I shows an exemplary arrangement 400I of a grating antenna including a first waveguide 460A, a second waveguide 460B, a third waveguide 460C, and grating elements 462. The grating elements 462 are arranged periodically according to a unit cell 464 having a non-constant grating element pitch (i.e., a non-constant spacing between grating elements 462). In this example, the three waveguides are interconnected by grating elements 462 extending over a distance that separates the waveguides. Such a design simplifies manufacturing and, due to better control of the relative positions of grating elements across two or more grating antennas, leads to faster manufacturing throughput and improved consistency between optical transmission and reception.

[0070] In some examples, an optical transceiver system may have one or more RX optical phased arrays having grating element pitches corresponding to each natural angular beam emitted by a grating antenna having a non-constant grating element pitch. In this case, such a transceiver can have a wide field of view for both transmission and reception.

[0071] Figure 5A shows three exemplary predictive plots (502A, 502B, and 502C) of light intensity as a function of angle in air for three corresponding grating antennas (504A, 504B, and 504C) having different grating element (506A, 506B, and 506C) arrangements optically coupled to their respective waveguides (508A, 508B, and 508C). The light wave propagates along the x-axis through waveguides 508A, 508B, and 508C. In the first grating antenna 504A, the grating elements 506A are arranged in a single column, with each grating element extending in a direction perpendicular to the propagation axis, in this example parallel to the y-axis. In the second grating antenna 504B, the grating elements 506B are arranged in two separate columns of the same pitch, but different parts of the grating elements are offset from each other by a first offset 507A. In the third grating antenna 504C, the grating elements 506C are arranged in two separate columns with the same pitch but different grating element portions further offset from each other by a second offset 507B, in this example, where the second offset 507B is greater than the offset of the second grating antenna 504B. In such a configuration, light waves traveling along the propagation axis through the grating antennas 504B and 504C are perturbed by the first portion of the grating elements and then by the second offset portion of the grating elements. Optical antennas capable of this perturbation are also shown in Figures 5B, 5C, 5D, and 6B. The first prediction plot 502A, corresponding to the first grating antenna 504A, shows a near-central emission pattern. The second prediction plot 502B, corresponding to the second grating antenna 504B, shows an angularly offset emission pattern. The third prediction plot 502C, corresponding to the third grating antenna 504C, shows an emission pattern that is further angularly offset compared to the second prediction plot 502B. Therefore, the emission pattern can be further angularly offset by increasing the offset between the two columns of grating elements.In some examples, more than two rows of grating elements may be used. In other examples, the grating elements may form two connected rows that are the same pitch but offset from each other, as shown in Figure 5C. In yet another example, the grating elements may form a single row that is non-orthogonal (i.e., at a constant angle) to the propagation axis of the waveguide in which they exist, as shown in Figure 6B. By arranging the grating elements such that flat wavefronts are perturbed (i.e., phase-shifted) at different positions along the propagation axis, light waves in the waveguide can have an angularly offset emission pattern. Furthermore, non-flat wavefronts can also be considered in the grating element arrangement to apply a desired angular offset.

[0072] Figure 5B shows an exemplary grating antenna 500B, which includes a waveguide 520 and grating elements 522 optically coupled to the waveguide 520. Along the direction parallel to the propagation axis of the waveguide 520, and in this example along the x-axis, the grating elements 522 are arranged in two separate rows of the same pitch, except that different grating element portions are offset from each other.

[0073] Figure 5C shows an exemplary grating antenna 500C, which includes a waveguide 530 and grating elements 532 optically coupled to the waveguide 530. Along the direction parallel to the propagation axis of the waveguide 530, the grating elements 532 are arranged in two connected rows of the same pitch, except that different grating element portions are offset from each other.

[0074] Figure 5D shows an exemplary grating antenna 500D, which includes a waveguide 540 and grating elements 542 optically coupled to the waveguide 540. Along the direction parallel to the propagation axis of the waveguide 540, the grating elements 542 are arranged in two rows of the same pitch but offset from each other. The two rows are connected by a strip 544 parallel to the propagation axis of the waveguide 540.

[0075] Figure 6A shows a predicted plot of an exemplary grating antenna 600A and the corresponding exemplary far-field radiation pattern 601A. The grating antenna 600A includes a waveguide 602 and a grating element 604 positioned perpendicular to the propagation axis of the waveguide 602. Thus, light 606 having a flat first wavefront 608A has no angular deflection and remains flat after propagating through the grating element 604, resulting in a flat second wavefront 608B. The far-field radiation pattern 601A is substantially centered at 0 degrees on the phase axis.

[0076] Figure 6B shows a predicted plot of an exemplary grating antenna 600B and the corresponding exemplary far-field radiation pattern 601B. The grating antenna 600B includes a waveguide 612 and grating elements 614 arranged non-orthogonal to the propagation axis of the waveguide 612. Thus, light 616 having a flat first wavefront 618A will, at different locations along the propagation axis, result in a flat second wavefront 618B having an angular deflection of φ, remaining flat after propagating through the grating elements 614, and propagating at a non-zero angle with respect to the phase axis, as different connections of one of the grating elements 614 perturb different portions of the wavefront 618A.

[0077] Figure 6C shows an exemplary configuration 600C of a grating antenna, which includes a first waveguide 622A, a second waveguide 622B, and grating elements 624 arranged non-orthogonally with respect to the propagation axes of each waveguide. Thus, light 626 having a flat first wavefront has angular deflection.

[0078] Figure 6D shows an exemplary configuration 600D of a grating antenna, which includes a first waveguide 632A, a second waveguide 632B, and grating elements 634 that are positioned non-orthogonal to the propagation axes of each waveguide and extend to both waveguides. Thus, light 636 having a flat first wavefront has angular deflection.

[0079] Figure 7A shows an exemplary arrangement of a grating antenna 700A that combines several features previously described in Figures 4F, 4I, 6C, and 6D. The grating antenna 700A includes a waveguide 701 and grating elements 702 periodically arranged according to a unit cell 704 having a non-constant grating element pitch (i.e., non-constant spacing between grating elements 702 within a unit cell compared to grating elements 702 within adjacent unit cells). In this example, there are grating elements 702 separated by distances on the order of the wavelength λ of light, while there are also grating elements 702 separated by larger distances such that the unit cell 704 has a length of 7 μm. By arranging the grating elements 702 in such a configuration, the grating antenna 700A can emit and receive multiple light beams around two vertical axes. Compared to the grating antenna 400D in Figure 4D, the grating antenna 700A in Figure 7A has grating elements arranged non-orthogonal to the propagation axis of the waveguide 701.

[0080] Figure 7B shows an exemplary configuration 700B of a grating antenna, which includes a first waveguide 720A, a second waveguide 720B, a third waveguide 720C, and grating elements 712 that are non-orthogonal to the propagation axis of each waveguide and extend across all waveguides. The grating elements 712 are periodically arranged according to a unit cell 714 having a non-constant grating element pitch (i.e., a non-constant spacing between grating elements 712 within a unit cell compared to grating elements 712 within adjacent unit cells). Similar to the grating antenna 400I shown in Figure 4I, such a design simplifies manufacturing and allows for faster manufacturing throughput and improved consistency of optical transmission and reception due to better control of the relative positions of grating elements across two or more grating antennas.

[0081] Although this disclosure has been described in relation to certain embodiments, it should be understood that this disclosure is not limited to the disclosed embodiments, but rather is intended to cover various modifications and equivalent arrangements included in the appended claims, and the scope should be given the broadest possible interpretation to include all modifications and equivalent structures permitted under the law.

Claims

1. It is a device, A light source port that provides a light wave having a tunable spectral peak wavelength, One or more transmitting optical phased arrays (OPAs), wherein each of the one or more transmitting OPAs is Connected to the aforementioned light source port, It includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of which is coupled to a different optical phase shifter among the plurality of optical phase shifters, The one or more transmitting OPAs are configured to form a plurality of beams, each of which is characterized by a wavelength control angle adjustment range in a first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane, A plurality of receiving OPAs, where each of the plurality of receiving OPAs is A coherent receiver connected to the light source port is coupled to the light source port, It includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of which is coupled to a different optical phase shifter among the plurality of optical phase shifters, A plurality of receiving OPAs are configured to receive light waves from a set of receiving angles characterized by a wavelength control angle adjustment range in the first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane. Includes, An apparatus wherein at least two of the wavelength control angle adjustment ranges of the plurality of beams are at least partially non-overlapping, and the wavelength control angle adjustment range of each of the plurality of receiving OPAs at least partially overlaps with at least one of the wavelength control angle adjustment ranges of the plurality of beams.

2. The apparatus according to claim 1, wherein the one or more transmitting OPAs include a plurality of transmitting OPAs, and each of the plurality of transmitting OPAs is configured to form one different of the plurality of beams.

3. At least one of the one or more transmitting OPAs is A waveguide configured to guide light waves along the propagation axis, Multiple sets of grating elements distributed along the waveguide and Includes, The multiple sets of grating elements are configured to perturb a portion of the light wave as it propagates along the waveguide, emitting multiple beams at different angles around an axis perpendicular to the propagation axis, and the multiple sets of grating elements are configured to perturb a portion of the light wave as it propagates along the waveguide, A first set of grating elements in which adjacent grating elements are separated from each other by a first length along the propagation axis, A second set of grating elements, wherein adjacent grating elements are separated from each other along the propagation axis by the first length, Includes, The apparatus of claim 1, wherein the second set of grating elements is separated from the first set of grating elements along the propagation axis by a gap in which no grating elements are present, and which is at least twice the length of the first set of grating elements.

4. The apparatus of claim 3, wherein each of the multiple sets of grating elements is in contact with a strip of material having substantially the same refractive index as the grating element.

5. The apparatus according to claim 3, wherein the one or more transmitting OPAs consist of a single transmitting OPA configured to form the plurality of beams.

6. The apparatus of claim 3, wherein each grating element of the plurality of sets of grating elements extends along a direction substantially perpendicular to the propagation axis.

7. Each of the aforementioned sets of grating elements is: A first portion is positioned at a first position along the propagation axis to perturb a first portion of the wavefront of the light wave, A second portion is positioned at a second position along the propagation axis, different from the first position, to perturb the second portion of the wavefront. Includes, The apparatus of claim 3, wherein the second portion of the wavefront does not overlap with the first portion of the wavefront at least partially.

8. A method for managing optical phased array beam steering, A light wave having a tunable spectral peak wavelength is supplied from at least one light source port, Transmitting multiple beams from one or more transmitting optical phased arrays (OPAs), wherein each of the one or more transmitting OPAs is Connected to the aforementioned light source port, It includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of which is coupled to a different optical phase shifter among the plurality of optical phase shifters, The one or more transmitting OPAs are configured to form a plurality of beams, each of which is characterized by a wavelength control angle adjustment range in a first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane, and transmits. The process involves receiving light waves into multiple receiving OPAs, wherein each of the multiple receiving OPAs is: A coherent receiver connected to the light source port is coupled to the light source port, It includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of which is coupled to a different optical phase shifter among the plurality of optical phase shifters, The system is configured to receive light waves from a set of receiving angles characterized by a wavelength control angle adjustment range in the first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane. Includes, A method wherein at least two of the wavelength control angle adjustment ranges of the plurality of beams are at least partially non-overlapping, and the wavelength control angle adjustment range of each of the plurality of receiving OPAs at least partially overlaps with at least one of the wavelength control angle adjustment ranges of the plurality of beams.

9. It is a device, A waveguide configured to guide light waves along the propagation axis, Multiple sets of grating elements distributed along the waveguide and Includes, The aforementioned sets of grating elements are configured to perturb a portion of the light wave as it propagates along the waveguide, emitting multiple beams at different angles around an axis perpendicular to the propagation axis. The aforementioned sets of grating elements are A first set of grating elements in which adjacent grating elements are separated from each other by a first length along the propagation axis, A second set of grating elements, wherein adjacent grating elements are separated from each other along the propagation axis by the first length, Includes, The apparatus wherein the second set of grating elements is separated from the first set of grating elements along the propagation axis by a gap in which no grating elements are present, and which is at least twice the length of the first set of grating elements.

10. A light source port that provides a light wave having a tunable spectral peak wavelength, Transmitting optical phased array (OPA), Connected to the aforementioned light source port, It includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of which is coupled to a different optical phase shifter of the plurality of optical phase shifters, wherein each optical grating antenna has a structure substantially identical to the waveguide and the plurality of sets of grating elements. A transmitting OPA is configured to form a plurality of beams, each characterized by a wavelength control angle adjustment range in a first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane. A plurality of receiving OPAs, where each of the plurality of receiving OPAs is A coherent receiver connected to the light source port is coupled to the light source port, It includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of which is coupled to a different optical phase shifter among the plurality of optical phase shifters, A plurality of receiving OPAs are configured to receive light waves from a set of receiving angles characterized by a wavelength control angle adjustment range in the first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane. The apparatus of claim 9, further comprising:

11. The method of claim 10, wherein at least two of the wavelength control angle adjustment ranges of the plurality of beams are at least partially non-overlapping, and the wavelength control angle adjustment range of each of the plurality of receiving OPAs at least partially overlaps with at least one of the wavelength control angle adjustment ranges of the plurality of beams.

12. The apparatus of claim 9, wherein each of the multiple sets of grating elements is in contact with a strip of material having substantially the same refractive index as the grating element.

13. Each of the aforementioned sets of grating elements is: A first portion is positioned at a first position along the propagation axis to perturb a first portion of the wavefront of the light wave, A second portion is positioned at a second position along the propagation axis, different from the first position, to perturb the second portion of the wavefront. Includes, The apparatus of claim 9, wherein the second portion of the wavefront does not overlap with the first portion of the wavefront at least partially.

14. A method for manufacturing optical devices, Forming at least one waveguide configured to guide light waves along the propagation axis, To form multiple sets of grating elements distributed along the waveguide. Includes, The aforementioned sets of grating elements are configured to perturb a portion of the light wave as it propagates along the waveguide, emitting multiple beams at different angles around an axis perpendicular to the propagation axis. The aforementioned sets of grating elements are A first set of grating elements in which adjacent grating elements are separated from each other by a first length along the propagation axis, A second set of grating elements, wherein adjacent grating elements are separated from each other along the propagation axis by the first length, Includes, A method wherein the second set of grating elements is separated from the first set of grating elements along the propagation axis by a gap in which no grating elements are present, and which is at least twice the length of the first set of grating elements.

15. It is a device, A waveguide configured to guide light waves along the propagation axis, Multiple grating elements distributed along the waveguide and Includes, The plurality of grating elements are configured to perturb a portion of the light wave as it propagates along the waveguide, and each of the plurality of grating elements is, A first portion is positioned at a first position along the propagation axis to perturb a first portion of the wavefront of the light wave, A second portion is positioned at a second position along the propagation axis, different from the first position, to perturb the second portion of the wavefront. Includes, The apparatus wherein the second portion of the wavefront does not overlap with the first portion of the wavefront at least partially.

16. Each of the aforementioned multiple grating elements is, The first portion that contacts the waveguide at the first position and extends along a direction substantially perpendicular to the propagation axis, The second portion that contacts the waveguide at the second position and extends along a direction substantially perpendicular to the propagation axis and The apparatus of claim 15, including the apparatus of claim 15.

17. The apparatus of claim 16, wherein the first portion and the second portion of a specific grating element are connected to each other.

18. The apparatus of claim 15, wherein the first portion and the second portion of a specific grating element are connected to each other.

19. Each of the aforementioned multiple grating elements is, The first portion that contacts the waveguide at the third position and extends at least to the first position, The second portion that contacts the waveguide at the third position and extends at least to the second position The apparatus of claim 18, including the apparatus of claim 18.

20. The apparatus of claim 18, wherein the particular grating element extends along a substantially straight line that makes an angle not perpendicular to the propagation axis.

21. A light source port that provides a light wave having a tunable spectral peak wavelength, A plurality of transmitting optical phased arrays (OPAs), wherein each of the plurality of transmitting OPAs is Connected to the aforementioned light source port, It includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of which includes two or more optical grating antennas coupled to different optical phase shifters of the plurality of optical phase shifters, wherein each optical grating antenna includes a structure substantially identical to the waveguide and the plurality of grating elements. A plurality of transmitting OPAs are configured to form a beam characterized by a wavelength control angle adjustment range in a first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane, A plurality of receiving OPAs, where each of the plurality of receiving OPAs is A coherent receiver connected to the light source port is coupled to the light source port, It includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of which includes two or more optical grating antennas coupled to different optical phase shifters of the plurality of optical phase shifters, wherein each optical grating antenna includes a structure substantially identical to the waveguide and the plurality of grating elements. A plurality of receiving OPAs are configured to receive light waves from a set of receiving angles characterized by a wavelength control angle adjustment range in the first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane. The apparatus of claim 15, further comprising:

22. At least two of the wavelength control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a wavelength control angle adjustment range that at least partially overlaps with the wavelength control angle adjustment range of at least one beam of the plurality of transmitting OPAs, or The apparatus according to claim 21, wherein at least two of the phase shift control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a phase shift control angle adjustment range that at least partially overlaps with the phase shift control angle adjustment range of at least one beam of the plurality of transmitting OPAs.

23. A method for manufacturing optical devices, Forming at least one waveguide configured to guide light waves along the propagation axis, Forming a plurality of grating elements distributed along the waveguide and Includes, The plurality of grating elements are configured to perturb a portion of the light wave as it propagates along the waveguide, Each of the aforementioned multiple grating elements is, A first portion is positioned at a first position along the propagation axis to perturb a first portion of the wavefront of the light wave, A second portion is positioned at a second position along the propagation axis, different from the first position, to perturb the second portion of the wavefront. Includes, A method wherein the second portion of the wavefront does not overlap with the first portion of the wavefront at least partially.

24. It is a device, A light source port that provides a light wave having a tunable spectral peak wavelength, A plurality of transmitting optical phased arrays (OPAs), wherein each of the plurality of transmitting OPAs is Connected to the aforementioned light source port, It includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of which is coupled to a different optical phase shifter among the plurality of optical phase shifters, A plurality of transmitting OPAs are configured to form a beam characterized by a wavelength control angle adjustment range in a first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane, A plurality of receiving OPAs, where each of the plurality of receiving OPAs is A coherent receiver connected to the light source port is coupled to the light source port, It includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of which is coupled to a different optical phase shifter among the plurality of optical phase shifters, A plurality of receiving OPAs are configured to receive light waves from a set of receiving angles characterized by a wavelength control angle adjustment range in the first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane. Includes, At least two of the wavelength control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a wavelength control angle adjustment range that at least partially overlaps with the wavelength control angle adjustment range of at least one beam of the plurality of transmitting OPAs, or An apparatus wherein at least two of the phase shift control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a phase shift control angle adjustment range that at least partially overlaps with the phase shift control angle adjustment range of at least one beam of the plurality of transmitting OPAs.

25. The apparatus of claim 24, wherein at least two of the wavelength control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a wavelength control angle adjustment range that at least partially overlaps with the wavelength control angle adjustment range of at least one beam of the plurality of transmitting OPAs.

26. The apparatus of claim 24, wherein at least two of the phase shift control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a phase shift control angle adjustment range that at least partially overlaps with the phase shift control angle adjustment range of at least one beam of the plurality of transmitting OPAs.

27. At least two of the wavelength control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a wavelength control angle adjustment range that at least partially overlaps with the wavelength control angle adjustment range of at least one beam of the plurality of transmitting OPAs, and The apparatus of claim 24, wherein at least two of the phase shift control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a phase shift control angle adjustment range that at least partially overlaps with the phase shift control angle adjustment range of at least one beam of the plurality of transmitting OPAs.

28. At least one of the plurality of transmitting OPAs is A waveguide configured to guide light waves along the propagation axis, Multiple sets of grating elements distributed along the waveguide and Includes, The aforementioned sets of grating elements are configured to perturb a portion of the light wave as it propagates along the waveguide, emitting multiple beams at different angles around an axis perpendicular to the propagation axis. The aforementioned sets of grating elements are A first set of grating elements in which adjacent grating elements are separated from each other by a first length along the propagation axis, A second set of grating elements, wherein adjacent grating elements are separated from each other along the propagation axis by the first length, Includes, The apparatus of claim 24, wherein the second set of grating elements is separated from the first set of grating elements along the propagation axis by a gap in which no grating elements are present, and which is at least twice the length of the first set of grating elements.

29. The apparatus of claim 28, wherein each of the multiple sets of grating elements is in contact with a strip of material having substantially the same refractive index as the grating element.

30. At least one of the plurality of transmitting OPAs is A waveguide configured to guide light waves along the propagation axis, Multiple grating elements distributed along the waveguide and Includes, The plurality of grating elements are configured to perturb a portion of the light wave as it propagates along the waveguide, emitting a plurality of beams at different angles around an axis perpendicular to the propagation axis. The aforementioned multiple grating elements are, A first portion is positioned at a first position along the propagation axis to perturb a first portion of the wavefront of the light wave, A second portion is positioned at a second position along the propagation axis, different from the first position, to perturb the second portion of the wavefront. Includes, The apparatus of claim 24, wherein the second portion of the wavefront does not overlap with the first portion of the wavefront at least partially.

31. The apparatus of claim 30, wherein the first portion and the second portion of a specific grating element are connected to each other.

32. A method for managing optical phased array beam steering, A light wave having a tunable spectral peak wavelength is supplied from at least one light source port, Transmitting beams from multiple transmitting optical phased arrays (OPAs), wherein each of the multiple transmitting OPAs is Connected to the aforementioned light source port, It includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of which is coupled to a different optical phase shifter among the plurality of optical phase shifters, A device configured to transmit, which forms a beam characterized by a wavelength control angle adjustment range in a first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane. The process involves receiving light waves into multiple receiving OPAs, wherein each of the multiple receiving OPAs is: A coherent receiver connected to the light source port is coupled to the light source port, It includes a plurality of tunable optical phase shifters and a plurality of optical grating antennas, each of which is coupled to a different optical phase shifter among the plurality of optical phase shifters, The system is configured to receive light waves from a set of receiving angles characterized by a wavelength control angle adjustment range in the first plane and a phase shift control angle adjustment range in a plane perpendicular to the first plane. Includes, At least two of the wavelength control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a wavelength control angle adjustment range that at least partially overlaps with the wavelength control angle adjustment range of at least one beam of the plurality of transmitting OPAs, or A method wherein at least two of the phase shift control angle adjustment ranges of the beams of the plurality of transmitting OPAs are at least partially non-overlapping, and each of the plurality of receiving OPAs has a phase shift control angle adjustment range that at least partially overlaps with the phase shift control angle adjustment range of at least one beam of the plurality of transmitting OPAs.

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