Optical beam sculpting assembly

Abstract

A light beam sculpting assembly defines the light beam characteristics of a light beam and includes a chip substrate, a beam forming and steering structure disposed on the chip substrate and configured to emit, receive, and / or control the light beam, and at least one phase mask, each phase mask having at least one corresponding core having a thickness and a height. The beam forming and control structure is disposed between the at least one phase mask and the chip substrate, and the at least one phase mask is configured to modify the light beam characteristics of the light beam. The light beam characteristics include at least one of a spatial distribution of light amplitude, a temporal distribution of light amplitude, light phase, polarization, and orbital angular momentum of light.

Description

Technical Field

[0001] The present invention relates to the fields of integrated photonics using optical phased arrays, target tracking and ranging, data processing and remote sensing, and more particularly to an optical beam sculpting assembly having stacked phase masks disposed or integrated on a beam forming and steering structure (e.g., an optical phased array or a focal plane switch array).

Background Art

[0002] Photonic components can be used to form and steer optical beams and define beam characteristics. The beam characteristics can have a spatial and / or temporal distribution of optical amplitude, optical phase, polarization, and optical orbital angular momentum (OAM). For example, by accurately defining the vector characteristics of an optical beam, spatial multiplexing of OAM information transmission beams for free-space transceivers can be realized. The ability to reliably define and modify beam characteristics is particularly useful in applications such as optical detection and ranging (LiDAR) systems and free-space transceivers.

[0003] Using the same structure or set of structures / components to simultaneously form, control, and define beam characteristics inherently involves trade-offs. Known beam forming and steering structures that often function in the visible, near-wavelength, and short-wavelength infrared regions include mechanical free-space optical components (e.g., mirrors, prisms, lenses), liquid crystals, and beam emitters composed of phase change materials. It can be difficult to directly define optical beam characteristics from a beam emitter (e.g., from an optical phased array OPA or a focal plane switch array FPSA). Characteristics of a beam emitter such as field of view and spot size are difficult to simultaneously solve only by the physical design of the beam emitter.

Summary of the Invention

Problems to be Solved by the Invention

[0004] An example of a set of such beam output structures for forming and controlling an optical beam using a focal plane switch array (FPSA) is reported in Opt. Exp. 29, 2021 by Chang et al. Chang et al. disclose a photonic component for beam forming and steering formed from three main components: a Mach-Zehnder optical switch, microring emitters, and a metalens. The metalens of Chang et al. is an essential part of the FPSA for beam forming and steering. Each component is essential for beam steering and without it, beam steering cannot be performed. The optical switch determines which microring emitters are activated. The optical beam from the activated microring emitters is controlled in a specific direction by the metalens. Since the optical beam obtained in the far field is due to Fraunhofer diffraction (not beam focusing by a lens etc.), the spatial width of the far-field optical beam increases as the distance between the beam emitter and the beam detection surface increases, similar to the case of other beam emitters. It is desirable to provide an improved photonic component for redefining and modifying the beam characteristics of an optical beam from a beam forming and steering structure (e.g., from an OPA or FPSA).

Means for Solving the Problems

[0005] According to a first aspect, a light beam sculpting assembly defines light beam characteristics of a light beam and includes a chip substrate, a beam forming and steering structure (e.g., an optical phased array (OPA) or a focal plane switch array (FPSA)) disposed on the chip substrate and configured to emit, receive, and / or control the light beam, and at least one phase mask. Each phase mask has at least one corresponding core having a thickness and a height. The beam forming and control structure is disposed between the at least one phase mask and the chip substrate, and the at least one phase mask is configured to modify the light beam characteristics of the light beam. The light beam characteristics include at least one of a spatial distribution of light amplitude, a temporal distribution of light amplitude, a light phase, polarization, and orbital angular momentum of the light beam.

[0006] From the foregoing disclosure and the following more detailed description of various embodiments, it will be apparent to those skilled in the art that the present invention provides a significant advance in the art of redefining and modifying a beam from a beam emitter. Of particular importance in this regard is the potential of the present invention to provide a beam forming and steering structure having controlled beam characteristics. Further features and advantages of the various embodiments will be better understood by considering the detailed description provided below.

Brief Description of the Drawings

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[0018] It should be understood that the accompanying drawings are not necessarily to scale and show somewhat simplified representations of various features that illustrate the basic principles of the present invention. For example, certain design features of the beamforming and steering structures disclosed herein, including certain dimensions of the phase mask layer, are partially determined by the particular intended application and use environment. Certain features of the illustrated embodiments are enlarged or distorted relative to others to aid in a clear understanding. In particular, thin features may be made thicker, for example, to clarify the illustration. All references to directions and positions refer to the directions illustrated in the drawings unless otherwise indicated.

Best Mode for Carrying Out the Invention

[0019] It will be apparent to those skilled in the art, i.e., those having knowledge or experience in this technical field, that many variations in use and design are possible for the optical beam sculpting assembly disclosed herein. The following detailed description of various alternative features and embodiments illustrates the general principles of the present invention with respect to an optical beam sculpting assembly suitable for redefining and modifying beam characteristics from beamforming and steering structures, particularly wide-angle beam steering. Other embodiments suitable for other applications will be apparent to those skilled in the art in view of the advantages of the present disclosure.

[0020] Disclosed herein is an optical beam sculpting assembly for modifying beam characteristics, including a phase mask stack 120 mounted on a beam forming and steering structure disposed on a chip substrate. The optical beam sculpting assembly includes a beam forming and steering structure and a phase mask. The beam forming and steering structure can include a plurality of components for beam forming and beam steering, for example, discriminative components for forming an optical beam and controlling the optical beam. These discriminative components can be integrated on the same platform, such as those of Chang et al., Opt. Exp. 29, 2021. The phase mask stack 120 advantageously provides the ability to adjust the characteristics of the beam from the beam forming and steering structure, including but not limited to the spatial and temporal distributions of optical amplitude, optical phase, polarization, and optical OAM. The phase mask can include, for example, any of silicon (Si), polysilicon, silicon nitride (Si3N4), silicon dioxide, germanium (Ge), lithium niobate (Li3NbO3), polymers, III-V compounds (i.e., alloys containing elements from groups III and V of the periodic table), and II-VI compounds (i.e., alloys containing elements from groups II and VI of the periodic table).

[0021] Referring to FIG. 1, there is disclosed a schematic block diagram 100 of an optical beam sculpting assembly 101 including at least one phase mask (P≧1) 121 of a phase mask stack 120 mounted on a beamforming and steering structure 110 disposed on a chip substrate 130. Each beamforming and steering structure 110 can include an array having beam emitters. Based on the configuration of the optical beam sculpting assembly 101 selected according to the application, any number of phase masks can be provided. The optical input field is sent to the beam emitters on the beamforming and steering structure 110 disposed on the chip substrate 130. The beam characteristics of the optical beam obtained from the array of beam emitters in 110 are defined by the phase mask stack 120. The beam emitters in 110 can include, for example, structures (such as grating structures) that induce light scattering to collectively generate an optical beam.

[0022] As shown in FIG. 1, the phase mask stacks p = 1, p = 2, …, p = P 121 are stacked perpendicular to each other. For example, the first phase mask p = 1 is stacked perpendicularly by the second phase mask p = 2, and the second phase mask p = 2 is stacked by the third phase mask p = 3. The first phase mask p = 1 is disposed on the beam forming and steering structure 110 disposed on the chip substrate 130. The phase masks p = 1, p = 2, …, p = P 121 and the beam forming and steering structure 110 are shown aligned on the chip substrate 130. Each phase mask can include a periodically arranged structure (core / pillar) having a cross-section of an ellipse, polygon, or closed Bézier curve, separated by a distance, and can be formed as a unit cell, as discussed in more detail below. The phase mask is configured to modify the optical beam characteristics of the optical beam. Such optical beam characteristics include, for example, at least one of the spatial distribution of the optical amplitude, the temporal distribution of the optical amplitude, the optical phase, the polarization, and the orbital angular momentum of the optical beam. Such modulation can further include modulation of the beam spot size, tilt angle, and field of view of the optical beam and can be configured to shift the directivity of the beam from the optical phased array.

[0023] Certain (overall) beam characteristics can optionally be modified independently and / or collectively by a plurality of phase masks 121. The phase masks can have the same, similar, or discriminative functions to define the desired optical beam characteristics. The characteristics can be sequentially modified as the optical beam passes through the phase mask stack layer by layer. Each phase mask can have various attributes that can be combined in a plurality of ways to improve the beam characteristics. The various dimensions of the optical phase mask, including the height of the core, the thickness or diameter of the core, are selected based on the desired phase shift at a particular position on the phase mask.

[0024] FIG. 2 is a table showing different types of optical phase masks, discrete and continuous phase masks, and binary and multi-valued. Preferably, in the optical beam sculpting assembly disclosed herein, at least a pair of optical phase masks are used, and each mask may be of a different type. The discrete binary (i.e., having two discrete levels of height) optical phase mask 121 has a core, in this case, a height h and a thickness (diameter when sculpted as a pillar having a substantially circular cross-section), and is shown with a phase mask unit cell 122 formed of pillars 126 having a distance between the pillars. In this embodiment, the pillars are surrounded by an underclad 125 and an overclad 124, and the core extends from the underclad to the overclad by its height only. The underclad 125 and the overclad 124 form part of each unit cell and may each include one or more standard photonic materials such as Si, polysilicon, Si3N4, Ge, Li3NbO3, polymers, and III-V compounds. Each of the cores corresponding to the array of unit cells is separated by either a uniform distance (to form a symmetric array) or a non-uniform distance. The stack of phase masks can be obtained using an overclad that is an underclad for the next layer of the optical phase mask. The thickness of the overclad can be, for example, from 0.01 μm to 5 μm. In a binary optical phase mask, the height of each pillar is uniform, but the thickness of each pillar and the distance between the pillars can vary. Such a photonic component with a discrete core height and fixed overclad and underclad thicknesses can be easily manufactured layer by layer using standard manufacturing techniques, and is advantageous when mass production is required for commercial expansion and economic sustainability of the beam sculpting assembly.

[0025] The discrete multi-valued optical phase mask 221 is a more general example of a discrete optical phase mask where the (core) height, thickness, and distance between cores can all vary. For example, in the exemplary multi-valued phase mask unit cell 222 of FIG. 2, it can be seen that the cores are formed with non-uniform heights and the distance between the cores of adjacent phase mask unit cells can be non-uniform. Advantageously, such a photonic component having a discrete multi-valued core height can be readily fabricated using standard manufacturing techniques and has a greater degree of freedom to sculpt beam characteristics compared to a phase mask having a discrete binary core height. The sculpted beam enables redefining and modifying the beam characteristics of an optical beam from a beamforming and steering structure.

[0026] In the case of a continuous optical phase mask 321, the core height can vary within and between each unit cell to form one or more continuous function curves. Here, the height is understood to mean the distance or length extending above the underclad and, as shown in FIG. 2, the height may advantageously be non-uniform. Further, in the embodiment of FIG. 2, the unit cell 322 is shown with a discontinuous or abrupt change in the height of the phase mask along with a series of continuous functions.

[0027] FIG. 3 shows an isometric schematic view of a binary phase mask, and FIG. 4 shows a unit cell of the binary phase mask of FIG. 3. The phase mask 121 includes a binary phase mask having a cylindrical core 126 and a phase mask unit cell 122. The distance between adjacent cores of each phase mask unit cell can be arbitrarily selected, and the dimensions (both height and diameter / diagonal / thickness) of the phase mask unit cell can be based on the intended phase shift at a specific position on the phase mask. The distance between adjacent cores of the phase mask unit cell may be the same or may vary. Optionally, the height of the phase mask unit cell can be between 0.01 μm and 10 μm, the diameter or cross-section of the core of the phase mask unit cell can be between 0.01 μm and 3 μm, and the periodic distance between adjacent phase mask unit cells can be arranged in a square lattice, for example, between 0.01 μm and 3 μm. A lattice refers to a regular arrangement of phase mask unit cells, for example, a two-dimensional lattice arrangement of triangular, square, or hexagonal phase mask unit cells. Advantageously, as shown in FIG. 1, at least one phase mask 121 can be stacked on the beamforming and steering structure.

[0028] The optical phase shift at the lattice points of each period is a function of the dimensions of the phase mask unit cell. In an example shown in FIG. 4, the phase mask unit cell core has a cylindrical pillar structure. The phase mask unit cell 122 can be a discrete (binary) phase mask having a cylindrical pillar structure with a height H that introduces the required phase shift. Alternatively, the phase mask unit cell 122 may be multi-valued or may have a continuous spatial height. The illustrated cylindrical pillar structure 123 has an elongated upper surface 127 and side walls 128 extending downward from the upper surface. The refractive index of the cylindrical pillar structure may be greater than or less than that of the surrounding cladding. In FIG. 4, the phase mask unit cell 122 introduces an optical phase shift based on its binary thickness structure. The different optical phase shifts induced by each phase mask unit cell 122 at different points on the phase mask 121, taken together, enable proper sculpting of the light beam from the beamforming and steering structure.

[0029] In one example, the binary thickness structure of the core 126 of the phase mask unit cell 122 is a cylindrical pillar structure having a thickness of 0.5 μm (consistently discrete). The cylindrical pillar structure is surrounded by an overclad 124 and an underclad 125 within the unit cell 122. The phase mask unit cell 122 receives an optical input field of amplitude a. The input optical field a propagates through the unit cell 122 and, by plane wave approximation, produces an output optical signal ae ikH where the wave vector k = 2πn eff / λ o , n eff is the effective refractive index of the pillar structure, and λ o is the wavelength of the optical field.

[0030] The optical phase shift at each periodic lattice point represented by the unit cell shown in FIG. 4 can be induced by either modifying k (function of n eff ) and / or modifying H. In one example, n effIt varies according to the diagonal or diameter D of the pillar structure. Advantageously, such a pillar structure (constituting the core) can be manufactured using standard manufacturing techniques such as lithography and deposition, and includes standard photonic materials such as Si, polysilicon, Si3N4, Ge, Li3NbO3, polymers, III-V compounds, etc. According to one embodiment, the height of each pillar within the phase mask unit cell is fixed based on layer-based deposition or etching processes in a conventional semiconductor manufacturing process. Advantageously, for the phase mask unit cell 122, the diameter of the pillar structure is a determining factor for introducing an optical phase shift. For example, for a polysilicon cylindrical pillar with a thickness of 0.5 μm surrounded by silicon dioxide overclad and underclad within a unit cell with a periodic distance of 0.65 μm between adjacent unit cells, diameters from 0.3575 μm to 0.6175 μm (i.e., 0.55 times to 0.95 times the periodic distance between adjacent unit cells) induce a monotonically increasing phase shift from 0 to 2π. Thus, the intended optical phase shift at any point on the phase mask can be designed according to a selection based on the relationship between the diameter and the induced optical phase shift from the diameter. Similarly, for a metasurface, the phase profile of the light beam is transformed based on a modulo 2π operation meaning that the radius of the pillar structure within the unit cell varies periodically. The phase profile of the light beam varies with the phase mask.

[0031] In one embodiment, the beam directivity shift is performed using a phase mask stack mounted on a beamforming and steering structure. In known beamforming and steering structures, wide-angle beam steering cannot be achieved or requires a large optical phase shifter, which may involve high energy consumption. The refractive index change for inducing the optical phase shift required for beam steering in known phase shifters is low (typically about 0.0001 for a PN-doped phase shifter and about 0.01 when heated at about 100 °C for a thermal phase shifter). In the case of a PN-doped phase shifter, the waveguide (forming part of the phase shifter) can be doped with a higher doping amount to further increase the refractive index change (increase the optical phase shift for beam steering), but the increase in doping concentration inevitably increases the optical loss in the doped waveguide, which is undesirable. In the case of a thermal phase shifter, the waveguide (constituting the phase shifter) can be heated more to further increase the refractive index change, but the required amount of heat may become prohibitively high. This is also undesirable. As a result, long phase shifters (> 10 μm) are typically used to compensate for the low refractive index change. Such problems can be addressed by implementing a layer of phase masks vertically integrated on a beamforming and steering structure (similar to that shown in FIG. 1) to define and modify the spatial distribution of the optical amplitude of the optical beam, i.e., to shift (e.g., amplify) the directivity of the beam in this example. FIG. 5 is a schematic diagram showing the mechanism of beam directivity shift using a phase mask stack, where layer i can be any layer from either the beamforming and steering structure 110 or the phase mask stack 121, e.g., the phase mask p121. Layer i + 1 is the layer above layer i. Layer i is composed of an array of beam emitters 112 from the beamforming and steering structure or an array of phase mask unit cells 122, while layer i + 1 is composed of an array of phase mask unit cells. When multiple phase masks are used for beam directivity shift, layer i can recursively refer to layer i + 1 of the previous iteration.

[0032] In FIG. 5, the light beam from layer i is incident at an angle θi from the vertical axis on the phase mask of layer i+1. As shown, the light beam propagates through the phase mask of layer i+1 at an angle θ i+1 shifted from the vertical axis (θ i+1 ≠θ i ). The phase mask can include thin-layer phase mask unit cells, and the thin layers are carefully designed and selected to shift the directivity of the light beam. In a preferred embodiment, the thickness of the phase mask unit cell can be from 0.01 μm to 5 μm to shift the directivity of the light beam to a specific angle (which can be from 0° to ±180°). In another preferred embodiment, the refractive index of the material of the surrounding layer can be varied from 1 to 5.

[0033] Advantageously, beam-forming and steering structures and / or beam emitters on the phase mask can be arranged periodically. Let the distance between the cores of each unit cell be d. Let the beam steering angle, which is the angle made by the light beam with respect to the vertical axis, be θ. The subscript of the variable indicates the layer to which the unit cell is referred, for example, layer i or i+1.

[0034] In FIG. 5, for layer i, Beam directivity:

Equation

[0035] In FIG. 5, for layer i+1: Beam directivity:

Number

Number

Number

Number

[0036] The beam directivity shift includes, but is not limited to, beam directivity amplification. For example, without loss of generality, considering only one beam forming and steering structure layer (i = 1) and one phase mask layer (P = 1, i.e., i = 2), and assuming θ1 = 10° = 0.1745 rad, Δφ1 = 30° = π / 6 rad, n 1,2 = n 2,3 , d1 = d2, it is. The beam directivity from layer 2 (from phase mask p = 1) is θ2 = sin -1 (1(1sin(0.1745)+1 / 6))~20° is. When adding phase mask p = 1, the directivity of the beam is amplified approximately twice from θ1 = 10° to θ2 ~ 20°. From the above derivation, it can be seen that for at least one phase mask, that is, I > 1 (including the beam forming and steering structure layer i = 1), i = 1, 2, …, I, the directivity of the beam is amplified by the following coefficient. [Number]

[0037] Figures 6, 7, and 8 show the finite difference time domain (FDTD) numerical simulation results of beam directivity shift using the vertical stacking of phase mask stacks on the OPA (beam forming and steering structure). In one example, the numerically simulated optical beam sculpting assembly has defined parameters. For example, a cylindrical pillar polysilicon structure with a thickness of 0.5 μm is used as the phase mask unit cell, with a pitch d = 0.65 μm, and represents a 2π phase shift with a radius in the range of (0.275 to 0.475)×d. Each layer also includes a silicon dioxide overclad with a thickness of 0.25 μm (between unit cell cores) and air in the region ahead of the topmost overclad. The beam directivity from the OPA is 10°.

[0038] Figure 6 is a table showing the numerical simulation results of the profile of the z - component of the electric field (E z ) of the photonic component (described in Figure 1) at Δφ = 30° along the xz cross - section disclosed with different numbers of phase masks (in three examples of the model in Figure 6, phase mask p = 1 only, layers p = 1 and 2, and layers p = 1, 2, and 3). Specifically, unit cell c x = 1, 2, …, C x (where C x(where \(C\) is the total number of unit cells in the \(x\)-direction), along the \(x\)-direction, the radius \(D / 2\) of the phase mask unit cell is \(c\) x It changes according to \(\Delta\varphi(\text{mod}360^{\circ}) / 360^{\circ}\times(0.475 - 0.275)d+0.275d\). The beam directions shifted by the phase mask are \(14.5^{\circ}\), \(26.7^{\circ}\), and \(40.6^{\circ}\) for the phase mask \(p = 1\) only, layers \(p = 1\) and \(2\), and layers \(p = 1\), \(2\), and \(3\), respectively.

[0039] Fig. 7 is another table similar to Fig. 6, but shows the estimated results of the \(z\)-component field profile of the electric field (\(E\) z ) of the additional embodiments of the photonic component at \(\Delta\varphi = 60^{\circ}\) along the \(xz\)-section disclosed with different numbers of phase masks (in two examples of the model in Fig. 7, the phase mask \(p = 1\) only, and layers \(p = 1\) and \(2\)). Specifically, for unit cells \(c\) x \(= 1,2,\cdots,C\) x (where \(C\) x is the total number of unit cells in the \(x\)-direction), along the \(x\)-direction, the radius \(D / 2\) of the phase mask unit cell is \(c\) x It changes according to \(\Delta\varphi(\text{mod}360^{\circ}) / 360^{\circ}\times(0.475 - 0.275)d+0.275d\). The beam directions shifted by the phase mask are \(14.5^{\circ}\), \(26.7^{\circ}\), and \(40.5^{\circ}\) for the phase mask \(p = 1\) only, and layers \(p = 1\) and \(2\), respectively. Fig. 8 is another table similar to Fig. 6, but shows the estimated results of the \(z\)-component of the field profile of the electric field (\(E\) z ) of the additional embodiments of the photonic component at \(\Delta\varphi=-120^{\circ}\) along the \(xz\)-section disclosed with different numbers of phase masks (in two examples of the model in Fig. 8, the phase mask \(p = 1\) only, and layers \(p = 1\) and \(2\)). Specifically, for unit cells \(c\) x \(= 1,2,\cdots,C\) x (where \(C\) x is the total number of unit cells in the \(x\)-direction), along the \(x\)-direction, the radius \(D / 2\) of the phase mask unit cell is \(c\) xIt changes according to Δφ (mod 360°) / 360°×(0.475 - 0.275)d + 0.275d. The beam directions shifted by the phase mask are 14.5° and -33.2° respectively in layer p = 1 and layers p = 1 and 2, only for the phase mask p = 1.

[0040] In known beamforming and steering structures, the spatial concentration of an optical beam in the far field spreads within a certain angle Δθ due to Fraunhofer diffraction. ff The resulting spatial width of the far - field beam is given by 2L tan(Δθ ff ). Here, L is the distance between the beamforming and steering structure and the detection or measurement plane. From this equation, it is clear that the spatial width of the far - field beam increases with the increase of L. This indicates beam divergence. Advantageously, the embodiments disclosed herein provide an additional layer of phase masks vertically integrated on the beamforming and steering structure layer (similar to that shown in FIG. 1) to spatially focus the optical beam to a single point at a predetermined or adjustable focal length, thereby addressing the aforementioned problem of beam divergence. FIGS. 9 and 10 show the use of phase masks for beam focusing. FIG. 9 is a table showing a schematic diagram showing the mechanism of beam focusing using a phase mask stack according to the embodiments disclosed herein for vertical and oblique optical beam incidence.

[0041] Layer i can be any layer and can be from the beamforming and steering structure 110 or the phase mask stack 121, for example, from the phase mask p121. Layer i + 1 is the layer above layer i. Layer i is composed of an array of beam emitters 112 from the beamforming and steering structure or an array of phase mask unit cells 122, while layer i + 1 may be composed of an array of phase mask unit cells.

[0042] In FIG. 9, the optical beam from layer i is incident on the phase mask on layer i + 1 at an angle θ from the vertical axis iIt is incident. As shown, the optical fields of the beams at different points propagate through the phase mask of layer i+1 at an angle shifted from the vertical axis in order to be focused at a focal length f having a focal plane 130, a focus 131 and an optical axis 132. In the case of an oblique optical field incident from layer i, the horizontal shift s from the focus 131 of the vertical optical field incident (from layer i) is s = f sin(θ i )). The phase mask can include a thin layer of phase mask unit cells for focusing the light beam. In a preferred embodiment, the thickness of the phase mask unit cell can be from 0.01 μm to 5 μm in order to shift the directivity of the light beam to a specific angle. In another preferred embodiment, the refractive index of the surrounding layer material can be in the range of 1 to 5.

[0043] Advantageously, the beam forming and steering structures and / or the beam emitters on the phase mask unit cells can be arranged periodically. The distance between each unit cell is denoted as d. Let the beam steering angle, which is the angle at which the light beam is formed with respect to the vertical axis, be θ. The subscript of the variable indicates the layer to which the unit cell is referred, for example layer i or i+1.

[0044] The phase mask for beam focusing is provided by designing to shift the optical phase of each adjacent phase mask unit cell in the horizontal direction by the following formula.

Equation

Equation

Equation

[0045] The phase mask stack 120 can include phase masks having the same and / or distinguishable functions to simultaneously achieve the same, similar, or distinguishable functions for modifying beam characteristics. For example, beam directivity amplification (θ i+1 >θ i)The phase mask stack 120 including a layer having a beam focusing function can be combined with the example shown in FIG. 11. The numerically simulated optical beam sculpting assembly has defined parameters. The parameters are determined based on the relationship between the diameter of the cylindrical pillars of a consistently fixed height within the unit cell and the induced optical phase shift of the optical field as the optical field propagates through the unit cell. For the layers for beam directivity (p = 1 and p = 2): A cylindrical pillar polysilicon structure with a thickness of 0.5 μm is used as the phase mask unit cell, with a pitch of d = 0.65 μm and a radius in the range of (0.275 to 0.475)×d, representing a 2π phase shift. Each layer also has a silicon dioxide overclad with a thickness of 0.25 μm (between unit cell cores). The beam directivity from the OPA is 10°, but the diameters of each adjacent unit cell in layers p = 1 and p = 2 are designed such that the overall beam directivity is 12.4°. As the layer for beam focusing (p = 3): A cylindrical pillar silicon nitride structure with a thickness of 0.5 μm is used as the phase mask unit cell, with a pitch of d = 0.8 μm and a radius in the range of (0.125 to 0.5)×d, representing a 2π phase shift. The discriminative radius of the cylindrical pillars in each phase mask unit cell is f = 170 μm based on Equation (4). Layer p = 3 has an air overclad. FIG. 11 is a schematic diagram of a combination of beam directivity shift and beam focusing according to an embodiment of the photonic component disclosed herein, and a table showing the estimated results of the electric field strength of the optical field from the optical beam sculpting assembly.

[0046] The devices disclosed herein are expandable, providing flexibility in vertically integrating an optical phase mask onto a beamforming and steering structure, and using discrete phase shift unit cells (i.e., phase mask unit cells) to modify beam characteristics from the beamforming and steering structure. Different phase masks having the same, similar, or discriminative functions that can be used by vertically integrating onto the beamforming and steering structure achieve multifunctional layers (function integration) on a single integration platform.

[0047] Furthermore, a beamforming and steering structure having vertically stacked phase masks is compact, and the integration is fully achieved on the chip substrate of the optical beam sculpting assembly. The phase mask can also be accurately positioned via chip design without the need for mechanical positioning, thereby enabling a robust system less prone to mechanical errors. The beamforming and steering structure is also cost - effective since the platform is fully integrated on - chip and additional phase masks can be conveniently added using the same manufacturing steps. Such convenience in manufacturing additional phase masks enables mass production of such devices, thereby improving cost - efficiency.

[0048] From the foregoing disclosure and the detailed description of specific embodiments, it is apparent that various modifications, additions, and other alternative embodiments are possible without departing from the true scope and spirit of the invention. The embodiments discussed were selected and described to provide the best illustration of the principles of the invention and its practical application, thereby enabling one of ordinary skill in the art to use the invention with various modifications suitable for the particular uses contemplated in various embodiments. All such modifications and variations are within the scope of the invention as determined by the appended claims and are applicable when they are interpreted in accordance with the scope to which they are fairly, legally, and equitably entitled.

Claims

1. An optical beam sculpting assembly that defines optical beam characteristics of an optical beam, comprising: a chip substrate; a beam forming and steering structure disposed on the chip substrate and configured to emit, receive, and / or control the optical beam; at least one phase mask, each phase mask having at least one corresponding core having a thickness and a height, an optical phased array being disposed between the at least one phase mask and the chip substrate, the at least one phase mask being configured to modify the optical beam characteristics of the optical beam; comprising the above in combination; wherein the optical beam characteristics include at least one of a spatial distribution of optical amplitude, a temporal distribution of optical amplitude, optical phase, polarization, and orbital angular momentum of light; an optical beam sculpting assembly.

2. Each of the at least one phase mask includes one of Si / SiO ２ , polysilicon, SiN ４ , SiO ２ , Ge, Li ３ NbO ３ , a polymer, a III-V compound, and a II-VI compound. The optical beam sculpting assembly according to Claim 1.

3. Each of the phase masks includes one of a discrete optical phase mask and a continuous optical phase mask; The optical beam sculpting assembly according to Claim 1.

4. The discrete optical phase mask includes one of a binary optical phase mask and a multi-valued optical phase mask; The optical beam sculpting assembly according to Claim 3.

5. Each of the phase masks adjusts at least one of a beam spot size, an inclination angle, and a field of view of the optical beam; The optical beam sculpting assembly according to Claim 1.

6. Each of the phase masks is configured to shift the directivity of the beam from the optical phased array; The optical beam sculpting assembly according to Claim 1.

7. Each of the phase masks includes an underclad and an overclad; The core extends by the height from the underclad toward the overclad; The optical beam sculpting assembly according to Claim 1.

8. Each phase mask includes a plurality of unit cells formed as an array; Each unit cell has one of the corresponding cores, and each of the corresponding cores is separated by one of a uniform distance and a non-uniform distance; The optical beam sculpting assembly according to Claim 7.

9. Each core has one of an elliptical, polygonal, and closed Bézier curve cross-section. The optical beam sculpting assembly according to claim 7.

10. Each of the phase masks has the same height, The optical beam sculpting assembly according to claim 1.

11. Further comprising at least two phase masks disposed above the optical phase assembly on the chip substrate, Each of the at least two phase masks adjusts at least one of the beam spot size, the beam tilt angle or directivity, and the beam field of view. The optical beam sculpting assembly according to claim 1.

12. The phase profile of the optical beam is converted based on modulo 2π arithmetic, The modulo 2π phase shift is a function of the thickness of the core within the phase mask unit cell. The optical beam sculpting assembly according to claim 1.

13. The at least one phase mask includes periodically arranged unit cells, Each of the unit cells has a corresponding core with a non-uniform height. The optical beam sculpting assembly according to claim 1.

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