Beam engraving assembly

Abstract

A beam sculpture assembly for defining beam characteristics of a beam includes a chip substrate, a beam forming and manipulating structure on the chip substrate for emitting, receiving and / or manipulating the beam, and at least one phase mask, each phase mask having at least one respective core, the core has a thickness and a height. The beam forming and manipulating structure is located between the at least one phase mask and the chip substrate, and the at least one phase mask is configured to modify a beam characteristic of the beam. The beam characteristics include at least one of a spatial distribution of light amplitude, a temporal distribution of light amplitude, an optical phase, polarization, and optical orbital angular momentum.

Description

Technical Field

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

[0002] Photonic elements can be used to form and manipulate light beams, as well as to define beam properties. The beam properties can have spatial and / or temporal distributions of optical amplitude, optical phase, polarization, and orbital angular momentum (OAM) of the light. For example, by being able to precisely define the vector properties of the beam, spatial multiplexing of OAM information-bearing beams for free-space transceivers can be achieved. The ability to reliably define and change beam properties is particularly useful in applications such as light detection and ranging (LiDAR) systems and free-space transceivers.

[0003] Using the same structure or set of structures / components to simultaneously form, manipulate, and define the characteristics of a beam necessarily introduces trade-offs. Known beam forming and manipulation structures that typically operate in the visible, near-wavelength, and short-wave infrared regions include beam launchers constructed from mechanical free-space optical elements (e.g., mirrors, prisms, and lenses), liquid crystals, and phase-change materials. Defining the beam characteristics directly from the beam launcher (e.g., from an optical phased array OPA or focal plane switch array FPSA) can be difficult. The advantages and disadvantages of a beam launcher, such as field of view and spot size, are difficult to address simultaneously through the physical design of the beam launcher alone.

[0004] Chang et al., in Opt (expiring Sept. 29, 2021), report an example of a set of beam-emitting structures that use a focal plane switch array (FPSA) to form and manipulate a beam. Chang et al. disclose a photonic assembly for beam forming and steering that consists of three main components: a set of Mach-Zehnder optical switches, a microring emitter, and a metalens. The metalens of Chang et al. is an integral part of the FPSA for beam forming and steering. Each component is a necessary condition for beam steering and cannot be performed without them. The optical switch determines the microring emitter that is activated. The beam from the activated microring emitter is manipulated into a certain direction by the metalens. Because the beam generated in the far field is due to Fraunhofer diffraction (rather than beam focusing, such as by a lens), the spatial width of the far-field beam increases with the distance between the beam emitter and the beam detection plane, as is the case with other beam emitters. It is desirable to provide an improved photonic assembly to redefine and modify the beam characteristics of a beam from a beam forming and steering structure (e.g., from an OPA or FPSA). Summary of the invention

[0005] According to a first aspect, a beam carving assembly defines 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)) located on the chip substrate for transmitting, receiving and / or steering 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 steering structure is located between the at least one phase mask and the chip substrate, and the at least one phase mask is configured to modify the beam characteristics of the light beam. The beam characteristics include at least one of a spatial distribution of light amplitude, a temporal distribution of light amplitude, an optical phase, a polarization, and an orbital angular momentum of light.

[0006] From the above disclosure and the more detailed description of various embodiments, it will be clear to those skilled in the art that the present invention has made significant progress in the art of redefining and modifying beams from beam emitters. Of particular importance in this regard is the potential for a beam forming and manipulating structure with controlled beam characteristics. Additional features and advantages of various embodiments will be better understood in light of the detailed description provided below. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a schematic diagram of a beam engraving assembly for display stacking layers according to an embodiment;

[0008] Figure 2 is a table showing different types of optical phase masks according to several embodiments;

[0009] Figure 3 is a schematic isometric view of a discrete binary phase mask for defining beam characteristics of a light beam according to one embodiment;

[0010] Figure 4 is a schematic isometric view of a phase mask unit according to one embodiment;

[0011] Figure 5 is a schematic diagram of beam directionality steering using a phase mask stack according to certain embodiments disclosed herein;

[0012] Figure 6 is along the xz cross section The electric field (E) of the additional embodiment of the photonic assembly is shown at z ) a table showing the variation of the z component of the estimated results of the field distribution;

[0013] Figure 7 is along the disclosed xz cross section The electric field (E) of the additional embodiment of the photonic assembly is shown at z ) a table showing the variation of the z component of the estimated results of the field distribution;

[0014] Figure 8 is along the xz cross section The electric field (E) of the additional embodiment of the photonic assembly is shown at z ) a table showing the variation of the z component of the estimated results of the field distribution;

[0015] Fig. 9 is a table showing schematic diagrams of beam focusing using a phase mask stack according to embodiments disclosed herein;

[0016] Fig.10 is the estimated electric field magnitude of the light field from the beam carving assembly according to the embodiments described herein; and

[0017] Fig.11 is a table showing representative combinations of beam directionality steering and beam focusing, and the estimated resulting electric field magnitude of the light field from the beam carving assembly.

[0018] It should be understood that the drawings are not necessarily drawn to scale, but rather present somewhat simplified representations of various features that illustrate the basic principles of the invention. The specific design features of the beam forming and steering structures disclosed herein, including, for example, the specific dimensions of the phase mask layer, will be determined in part by the specific intended application and use environment. Certain features of the illustrated embodiments are enlarged or distorted relative to other features to help provide a clear understanding. In particular, thin features may be thickened, for example, for clarity of illustration. Unless otherwise specified, all references to directions and positions refer to the directions shown in the drawings. DETAILED DESCRIPTION

[0019] It will be apparent to those skilled in the art, i.e., those with knowledge or experience in the art, that the beam carving assemblies disclosed herein may have many uses and design variations. The following detailed discussion of various alternative features and embodiments illustrates the general principles of the invention with reference to beam carving assemblies suitable for redefining and modifying beam characteristics from beam forming and steering structures, particularly wide-angle beam steering. Other embodiments suitable for other applications will be apparent to those skilled in the art, given the benefit of this disclosure.

[0020] Disclosed herein is a beam sculpting assembly for modifying beam characteristics, comprising a phase mask stack 120 mounted on a beam forming and steering structure located on a chip substrate. The beam sculpting assembly comprises a beam forming and steering structure and a phase mask. The beam forming and steering structure may include multiple components for beam forming and beam steering, for example, different components for forming a beam and for steering a beam. These different components may be integrated onto the same platform, for example, Opt by Chang et al. (expiring September 29, 2021). The phase mask stack 120 advantageously provides the ability to adjust beam characteristics from the beam forming and steering structure, including but not limited to any one of the spatial and temporal distribution of optical amplitude, optical phase, polarization, optical OAM, or a combination of both. The phase mask may include, for example, any one of silicon (Si), polysilicon, silicon nitride (Si3N4), silicon dioxide, germanium (Ge), lithium niobate (Li3NbO3), polymers, Group III-V compounds (i.e., compounds containing elements from Group III and Group V of the periodic table), and Group II-VI compounds (i.e., compounds containing elements from Group II and Group VI of the periodic table).

[0021] refer to Figure 1 , discloses a schematic block diagram 100 of a beam carving assembly 101, which includes at least one phase mask (P≥1) 121 of a phase mask stack 120 mounted above a beam forming and steering structure 110 located on a chip substrate 130. Each beam forming and steering structure 110 may include an array with beam emitters. There may be any number of phase masks based on the configuration of the beam carving assembly 101 selected for the application. An optical input field is sent to the beam emitters on the beam forming and steering structure 110 located on the chip substrate 130. The beam characteristics of the resulting beam from the array of beam emitters in 110 are defined by the phase mask stack 120. For example, the beam emitters in 110 may include a structure that induces light scattering (e.g., a grating structure) to collectively produce a beam.

[0022] like Figure 1As shown, the phase mask stacks ρ=1, ρ=2, ..., ρ=P 121 are stacked vertically together. For example, the first phase mask ρ=1 is stacked vertically by the second phase mask ρ=2, and the second phase mask ρ=2 is stacked by the third phase mask ρ=3. The first phase mask ρ=1 is located above the beam forming and steering structure 110, which is in turn located on the chip substrate 130. The phase masks ρ=1, ρ=2, ..., ρ=P 121 and the beam forming and steering structure 110 are shown as aligned on the chip substrate 130. Each phase mask can include periodically placed structures (cores / pillars) having an elliptical, polygonal or closed Bezier curve cross-section, separated by a distance, and can be formed into a unit cell, as discussed in more detail below. The phase mask is configured to modify the beam characteristics of the light beam. For example, such beam characteristics include at least one of the spatial distribution of light amplitude, the temporal distribution of light amplitude, the optical phase, the polarization, and the orbital angular momentum of the light. Such modulation may also include modulation of the beam's spot size, tilt angle, and field of view, as well as being configured to steer the directionality of the beam from an optical phased array.

[0023] Specific (overall) beam characteristics can optionally be modified independently and / or collectively by multiple phase masks 121. Phase masks can have the same, similar, or different functions to define the desired beam characteristics. The characteristics can be modified sequentially as the beam passes through the phase mask stack layer by layer. Each phase mask can have various properties that can be combined in a variety of ways to provide enhanced beam characteristics. Various dimensions of the optical phase mask, including core height, core thickness, or diameter, are selected based on the expected phase shift at a specific location on the phase mask.

[0024] Figure 2is a table showing different types of optical phase masks, discrete and continuous phase masks, as well as binary and multi-level. Preferably, at least one pair of optical phase masks is used in the beam carving assembly disclosed herein, and each mask can be of a different type. A discrete binary (i.e., a core with two discrete height levels) optical phase mask 121 is shown having a phase mask unit cell 122 formed by a core, in which case the pillars 126 have a height h and a thickness (or diameter when the shape is a pillar with a substantially circular cross-section), and there is a distance between the pillars. In this embodiment, the pillars are surrounded by a lower cladding 125 and an upper cladding 124, and the core extends from the lower cladding to the upper cladding in height. The lower cladding 125 and the upper cladding 124 form part of each unit cell and can each include one or more standard photonic materials, such as Si, polysilicon, Si3N4, Ge, Li3NbO3, polymers, and III-V compounds. Each core corresponding to the unit cell array is separated by a uniform distance (forming a symmetrical array) and a non-uniform distance. A phase mask stack can be obtained using an upper cladding, which is a lower cladding of the next optical phase mask. The thickness of the upper cladding can be, for example, 0.01 μm to 5 μm. In a binary optical phase mask, the height of each column is uniform, but the thickness and distance between each column may vary. When we need commercially scalable and economically sustainable mass-produced beam sculpting components, such photonic elements with discrete core heights and fixed upper and lower cladding thicknesses are advantageous because they can be conveniently manufactured layer by layer using standard manufacturing techniques.

[0025] Discrete multi-level optical phase mask 221 is a more general example of a discrete optical phase mask, in which the height, thickness, and distance between cores can vary. Figure 2 In the example multi-level phase mask unit cell 222, it can be seen that the core heights are not uniform, and the distances between the cores of adjacent phase mask units are also not uniform. Advantageously, such photonic elements with discrete multi-level core heights can be easily produced using standard manufacturing techniques, and have greater freedom to sculpt beam characteristics than phase masks with discrete binary core heights. The sculpted beam is able to redefine and modify the beam characteristics of the beam from the beam forming and steering structure.

[0026] For the continuous optical phase mask 321, the height of the core can be varied within each unit cell and between unit cells to form one or more continuous function curves. The height here refers to the distance or length extending above the lower cladding, such as Figure 2 As shown, the height can advantageously be non-uniform. Figure 2 In the embodiment of FIG. 3 , unit cell 322 is shown as having a series of continuous functions, as well as discontinuous or abrupt changes in phase mask height.

[0027] Figure 3 An isometric schematic diagram of a binary phase mask is shown. Figure 4 Shows Figure 3 The phase mask 121 comprises 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 can be arbitrarily selected, and the size (height and diameter / diagonal / thickness) of the phase mask unit cell can be based on the expected phase shift at a specific location on the phase mask. The distance between adjacent cores of the phase mask unit cell can be the same or can 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 phase mask unit cell core can be between 0.01 μm and 3 μm, and the periodic distance between adjacent phase mask unit cells can be in a square lattice between 0.01 μm and 3 μm. The lattice refers to a regular arrangement of phase mask unit cells, for example, a triangular, square or hexagonal two-dimensional lattice arrangement of phase mask unit cells. Advantageously, as Figure 1 As shown, at least one phase mask 121 may be stacked above the beam forming and steering structure.

[0028] The optical phase shift of each periodic lattice point is a function of the phase mask unit cell size. Figure 4 In one example shown, the phase mask unit core has a cylindrical pillar structure. The phase mask unit cell 122 can be a discrete (binary) phase mask having a cylindrical pillar structure of height H, introducing the desired phase shift. Alternatively, the phase mask unit cell 122 can be multi-level, or can have a continuous spatial height. The cylindrical pillar structure 123 shown has an elongated top surface 127 and sidewalls 128 extending downward from the top surface. The refractive index of the cylindrical pillar structure can be greater or less than the surrounding cladding. In Figure 4 In the embodiment of the present invention, the phase mask unit cell 122 introduces an optical phase shift based on its binary thickness structure. The different optical phase shifts caused by each phase mask unit cell 122 at different points on the phase mask 121 are combined so that the beam from the beam forming and steering structure can be reasonably carved.

[0029] In one example, the binary thickness structure of the core 126 of the phase mask unit cell 122 is a cylindrical pillar structure with a thickness of 0.5 μm (continuously discrete). The cylindrical pillar structure is surrounded by an upper cladding 124 and a lower cladding 125 in the unit cell 122. The phase mask unit cell 122 receives an optical input field with an amplitude a. The input optical field a propagates through the unit cell 122, and an output optical signal ae is generated by plane wave approximation. ikH , where the wave vector k = 2πn eff / λ0,n eff is the effective refractive index of the pillar structure, and λ0 is the wavelength of the light field.

[0030] Figure 4 The optical phase shift of each periodic lattice point represented by the unit cell shown can be modified by modifying k (which is n eff function) and / or modify H to cause. In one example, n eff The phase mask unit cell 122 is formed by a phase mask having a diameter D that varies with the diagonal or diameter D of the column structure. Advantageously, such a column structure (constituting the core) can be produced using standard manufacturing techniques (such as lithography and deposition) and includes standard photonic materials such as Si, polysilicon, Si3N4, Ge, Li3NbO3, polymers, and III-V compounds. According to one embodiment, the height of each column in the phase mask unit cell is fixed based on a layer-based deposition or etching process in a conventional semiconductor manufacturing process. Advantageously, for the phase mask unit cell 122, the diameter of the column structure is the determining factor in introducing an optical phase shift. For example, for a polysilicon cylindrical column with a thickness of 0.5 μm, surrounded by a silicon dioxide upper cladding and a lower cladding, and a periodic distance between adjacent units in the unit cell of 0.65 μm, a diameter of 0.3575 μm to 0.6175 μm (i.e., 0.55 to 0.95 times the periodic distance between adjacent units) will cause a monotonically increasing phase shift of 0 to 2π. Therefore, the expected optical phase shift at any arbitrary point on the phase mask can be designed based on the relationship between the diameter and the optical phase shift induced from the diameter. In a similar way, for the metalens, the phase distribution of the beam is transformed based on the modulo 2π operation, which means that the radius of the pillar structure in the unit cell changes periodically. The phase distribution of the beam is changed by the phase mask.

[0031] In one embodiment, beam directionality manipulation is performed using a phase mask stack mounted above a beam forming and steering structure. In known beam forming and steering structures, wide angle beam steering may not be achievable or require large optical phase shifters, which may involve significant energy consumption. In known phase shifters, the refractive index change that causes the optical phase shift required for beam steering is low (typically about 0.0001 in PN doped phase shifters and about 0.01 when heated at about 100°C in thermal phase shifters). For PN doped phase shifters, although the waveguide (forming part of the phase shifter) can be doped with higher dopant levels to further increase the refractive index change (which increases the optical phase shift for beam manipulation), the increase in doping concentration inevitably increases optical losses in the doped waveguide, which is undesirable. For thermal phase shifters, although the waveguide (forming the phase shifter) can be heated to a greater extent to further increase the refractive index change, the amount of heat required may be too high. This is also undesirable. Therefore, long phase shifters (>10μm) are typically used to compensate for the low refractive index change. These problems can be solved by adding a phase mask stack to the beam forming and steering structure (similar to Figure 1 A phase mask layer is integrated vertically above the beam (as shown) to define and modify the spatial distribution of the light amplitude of the beam, i.e., in this example to shift (e.g., amplify) the directionality of the beam. Figure 5 A schematic diagram of a beam directionality steering mechanism using a phase mask stack is shown, where the i-th layer can be any arbitrary layer from the beam forming and steering structure 110 or the phase mask stack 121, for example, phase mask p121. The i+1 layer is the layer above the i-th layer. The i-th layer can include an array of beam emitters 112 from the beam forming and steering structure, or an array of phase mask cells 122, and the i+1 layer includes an array of phase mask cells. When multiple phase masks are used for beam directionality steering, the i-th layer can recursively refer to the i+1-th layer in the previous iteration.

[0032] exist Figure 5 In the example, the beam from the i-th layer is at an angle θ to the vertical axis. i As shown in the figure, the light beam passes through the phase mask in the i+1th layer at an angle θ that deviates from the vertical axis. i+1 propagation, where θ i+1 ≠θ i The phase mask may include a thin layer of phase mask cells that are judiciously designed and selected to change the directivity of the light beam. In a preferred embodiment, the thickness of the phase mask cells may be 0.01 μm to 5 μm to shift the directivity of the light beam to a specific angle, which may be 0° to ±180°. In another preferred embodiment, the refractive index of the surrounding layer material may vary from 1 to 5.

[0033] Advantageously, the beam emitters on the beam forming and steering structure and / or phase mask may be placed periodically. The distance between each core of each unit cell is denoted by d. The beam direction angle, i.e. the angle formed by the beam relative to the vertical axis, is denoted by θ. The subscripts of the variables indicate the layer of the unit cell being referenced, e.g., the i-th layer or the i+1-th layer.

[0034] exist Figure 5 For the i-th layer: Beam directivity: in, λ i,i+1 =λ0 / n i,i+1 , is the effective refractive index n i,i+1 The effective wavelength of the light field in free space of the i-th upper cladding (i.e., the i+1-th lower cladding); λ0 is the wavelength of the light field; d i is the distance between the centers of adjacent unit cells in the i-th layer; is the optical phase difference of the light field at the i-layer unit cell.

[0035] exist Figure 5 For the i+1th layer: Beam directivity: Among them, λ i+1,i+2 =λ0 / n i+1,i+2 , is the effective refractive index n i+1,i+2 The effective wavelength of the light field in free space of the i+1th upper cladding (i.e., the i+2th lower cladding); d i+1 is the distance between the centers of adjacent unit cells in the i+1th layer; is the optical phase difference of the light field of the i+1th layer of the unit cell. Advantageously, by using Figure 3 The column structure in the i+1th layer induces a phase shift, and the overall phase shift of the structure is in is the optical phase incident on the i+1th layer of the unit cell from the i-th layer; and is the optical phase introduced due to the unit cell size, assuming that the unit cells in the i+1th layer always have the same height H i+1 .

[0036] Beam directional manipulation includes but is not limited to beam directional amplification. For example, without loss of generality, only one beam forming and manipulation structure layer (i.e., i=1) and one phase mask layer (ρ=1, i=2) are considered, and θ1=10°=0.1745rad. ; n 1,2 =n 2,3 ; d1=d2; The directivity of the beam from layer 2 (from phase mask ρ=1) is: θ2=sin -1 (1(1sin(0.1745)+1 / 6))~20° Adding a phase mask ρ = 1 results in the beam directivity being amplified by about a factor of 2 from θ1 = 10° to θ2 ~ 20°. From the above derivation, it can be seen that for at least one phase mask, I>1 (including the beam forming and steering structure layer i = 1), where I = 1, 2, ..., I, the beam directivity is amplified by a factor of θ2 ~ 20°.

[0037] Figure 6 , 7and 8 show the results of numerical finite-difference time-domain (FDTD) simulations of beam directionality steering using a vertical stack of phase mask stacks on an OPA (a beam forming and steering structure). In one example, the numerically simulated beam carving component defines parameters such as 0.5 μm thick cylindrical pillar-shaped polysilicon structures as phase mask cells with a spacing of d = 0.65 μm and a radius ranging from (0.275 to 0.475) x d, representing a 2π phase shift. Each layer is also provided with a 0.25 μm thick silica cladding (between the cell cores) and air in the region outside the topmost cladding. The beam is oriented at 10° to the OPA.

[0038] Figure 6 is a table showing the xz cross section At, photonic components (such as Figure 1 The electric field (E) of the embodiment shown in FIG. z )Z-component distribution numerical simulation results, this cross section uses different numbers of phase masks (in Figure 6 In the three examples of the model, the phase mask ρ = 1 layer, the phase mask ρ = 1 and 2 layers, and the phase mask ρ = 1, 2 and 3 layers. Specifically, from the unit cell c x =1,2,…,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 calculated according to When the phase mask is ρ=1 layer, ρ=1 and 2 layers, and ρ=1, 2 and 3 layers, the beam direction is steered at angles of 14.5°, 26.7° and 40.6°, respectively.

[0039] Figure 7 is with Figure 6 Another similar table, but with a cross section along xz The electric field (E) of other embodiments of the photonic assembly at z ) field distribution, where different numbers of phase masks (in Figure 7 In the two examples of the model, the phase mask ρ = 1 layer and the phase mask ρ = 1 and 2 layers. Specifically, from the unit cell c x =1,2,…,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 calculated according to When the phase mask is ρ=1 layer, ρ=1 and 2 layers, the beam direction is steered at 14.5°, 26.7° and 40.5° respectively. Figure 8 is with Figure 6 Another similar table, but with a cross section along xz The electric field (E) of other embodiments of the photonic assembly at z ) field distribution, where different numbers of phase masks (in Figure 8 In the two examples of the model, the phase mask ρ = 1 layer and the phase mask ρ = 1 and 2 layers. Specifically, from the unit cell c x =1,2,…,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 calculated according to When the phase mask is ρ=1, ρ=1 and 2 layers, the phase mask manipulates the beam direction by 14.5° and -33.2° respectively.

[0040] In known beam forming and steering configurations, the spatial concentration of the beam in the far field is at a certain angle Δθ due to Fraunhofer diffraction. ff The final spatial width of the far-field beam is given by 2Ltan(Δθ ff ), where L is the distance between the beam forming and steering structure and the detection or measurement plane. It is evident from this expression that the spatial width of the far-field beam increases as L increases. This indicates beam divergence. Advantageously, the embodiments disclosed herein also provide a layer of beam forming and steering structures (similar to Figure 1 The above-mentioned beam divergence problem is solved by an additional layer of phase mask integrated vertically above the optical layer 20 (as shown) to spatially focus the beam to a single point of predetermined or adjustable focal length. Fig. 9 and Fig.10 Demonstrated the use of phase masks for beam focusing. Fig. 9 is a table showing schematic diagrams of the mechanisms of beam focusing using a phase mask stack under normal and oblique beam incidence according to embodiments disclosed herein.

[0041] The i-th layer may be any arbitrary layer and may be from the beam forming and steering structure 110 or the phase mask stack 121, for example, the phase mask p 121. The i+1 layer is the layer above the i-th layer. The i-th layer may include an array of beam emitters 112 or a phase mask cell array 122 from the beam forming and steering structure, while the i+1 layer includes a phase mask cell array.

[0042] exist Fig. 9 In the example, the beam from the i-th layer is at an angle θ to the vertical axis. iThe light field of the beam at different points then propagates through the phase mask in the i+1th layer at an angle off the vertical axis to be focused at a focal length f, with a focal plane 130, a focal point 131, and an optical axis 132. For the oblique light field incident on the i-th layer, the horizontal manipulation s of the focal point 131 of the vertical light field incident (from the i-th layer) is s=fsin(θ i )). The phase mask may include a thin layer of phase mask cells for focusing the light beam. In a preferred embodiment, the thickness of the phase mask cells may be 0.01 μm to 5 μm to manipulate the directionality of the light beam to a specific angle. In another preferred embodiment, the refractive index of the surrounding layer material may be in the range of 1 to 5.

[0043] Advantageously, the beam emitters on the beam forming and steering structure and / or phase mask unit cells can be placed periodically. The distance between each unit cell is denoted as d. The beam direction angle, i.e. the angle formed by the beam relative to the vertical axis, is denoted as θ. The subscripts of the variables indicate the layer of the unit cell being referenced, for example, the i-th layer or the i+1-th layer.

[0044] By designing the optical phase of each horizontally adjacent phase mask unit cell to be offset, a phase mask for beam focusing is provided. Among them, for line focusing, For point focusing, x is the distance corresponding to Δr In one example, a numerically simulated beam sculpting component has defined parameters, e.g., 0.4 μm thick cylindrical pillar-shaped polysilicon structures as phase mask cells, with a spacing of d = 0.75 μm and a radius range of (0.05 to 0.5) x d, representing a 2π phase shift. The specific radius of the cylindrical pillars in each phase mask cell is calculated based on equation (4), where f = 170 μm. The i-th layer = 1 (beam forming and steering structure portion) provides a 0.25 μm thick upper cladding of silicon dioxide (between the cell cores), while the i-th layer = 2 (i.e., p = 1 layer; the top layer) provides an upper cladding of air. Fig.10 The estimated electric field magnitude of the light field produced by the beam carving assembly is shown.

[0045] The phase mask stack 120 may include phase masks having the same and / or different functions to simultaneously implement the same, similar, or different functions to modify the characteristics of the beam. For example, a combination of phase masks having a beam directivity magnification (θ i+1 >θ i ) and a phase mask stack 120 of a layer having a beam focusing function, such as Fig.11As shown. The numerically simulated beam carving component has defined parameters. These parameters are determined based on the relationship between the diameter of the cylindrical pillars with constant height in the unit cell and the phase shift of the light field caused when the light field propagates in the unit cell. For the beam directivity layer (ρ=1 and ρ=2): 0.5μm thick cylindrical pillar-shaped polysilicon structures serve as phase mask unit cells with a spacing of d=0.65μm and a radius range of (0.275 to 0.475)xd, indicating a 2π phase shift. Each layer is also covered with 0.25μm thick silicon dioxide (between the unit cell cores). The beam directivity of the OPA is 10°, and the diameter of each adjacent unit cell in the ρ=1 and ρ=2 layers is designed to provide an overall beam directivity of 12.4°. For the beam focusing layer (p=3): 0.5 μm thick cylindrical pillar-shaped silicon nitride structures as phase mask cells with a spacing of d=0.8 μm and a radius range of (0.125 to 0.5) xd, representing a 2π phase shift. The specific radius of the cylindrical pillars in each phase mask cell is based on equation (4) with f=170 μm. The p=3 layer is provided with an air envelope. Fig.11 is a table showing a schematic diagram of a combination of beam directionality steering and beam focusing according to one embodiment of a photonic assembly disclosed herein, and an estimated electric field amplitude of a light field produced by the beam sculpting assembly.

[0046] Therefore, the device disclosed in this article is scalable and provides flexibility to vertically integrate optical phase masks onto beam forming and steering structures, and use discretized phase shift unit cells (i.e., phase mask unit cells) to modify the beam characteristics of the beam forming and steering structures. Different phase masks with the same, similar or different functions can be used by vertical integration above the beam forming and steering structures, thereby realizing a multifunctional layer (feature integration) on a single integrated platform.

[0047] Furthermore, the beam forming and steering structure with vertically stacked phase masks is compact and fully integrated on the chip substrate of the beam engraving assembly. The phase masks can also be precisely positioned by the chip design without the need for any mechanical positioning, making the system less prone to mechanical errors. The beam forming and steering structure is also cost-effective because the platform is fully integrated on the chip and additional phase masks can be conveniently added using the same manufacturing steps. This ease of manufacturing additional phase masks enables the mass production of such devices, thereby improving cost efficiency.

[0048] It will be apparent from the foregoing disclosure and detailed description of certain embodiments that various modifications, additions and other alternative embodiments may be made without departing from the true scope and spirit of the invention. The embodiments discussed have been selected and described in order 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 in various embodiments and with various modifications to suit the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally and equitably entitled.

Claims

1. A beam carving assembly for defining beam characteristics of a beam, the beam carving assembly comprising the following combination: Chip substrate; A beam forming and steering structure located on the chip substrate for transmitting, receiving and / or steering a beam; as well as at least one phase mask, each phase mask having at least one corresponding core, the core having a thickness and a height, wherein the optical phased array is located between the at least one phase mask and the chip substrate, and the at least one phase mask is configured to modify beam characteristics of the light beam; The light beam characteristics include at least one of the spatial distribution of light amplitude, the temporal distribution of light amplitude, optical phase, polarization and light orbital angular momentum.

2. The beam engraving assembly according to claim 1, wherein: The at least one phase mask each includes one of Si / SiO2, polysilicon, SiN4, SiO2, Ge, Li3NbO3, a polymer, a III-V compound, and a II-VI compound.

3. The beam engraving assembly according to claim 1, wherein: Each of the phase masks comprises one of a discrete optical phase mask and a continuous optical phase mask.

4. The beam engraving assembly according to claim 3, wherein: The discrete optical phase mask includes one of a binary optical phase mask and a multi-level optical phase mask.

5. The beam carving assembly according to claim 1, wherein: Each of the phase masks modulates at least one of a spot size, a tilt angle, and a beam field of view of the light beam.

6. The beam carving assembly according to claim 1, wherein: Each of the phase masks is configured to steer the directionality of a light beam from the optical phased array.

7. The beam carving assembly according to claim 1, wherein: Each of the phase masks includes a lower cladding and an upper cladding, and the core extends from the lower cladding to the upper cladding by the height.

8. The beam carving assembly according to claim 7, wherein: Each of the phase masks includes a plurality of unit cells formed into an array, each unit cell having one of the corresponding cores, each of the corresponding cores being separated by one of a uniform distance and a non-uniform distance.

9. The beam carving assembly according to claim 7, wherein: Each of the cores has one of an ellipse, a polygon and a closed Bezier curve cross section.

10. The beam carving assembly of claim 1, wherein: Each of the phase masks has the same height.

11. The beam engraving assembly according to claim 1 further includes at least two phase masks located above the optical phase array on the chip substrate, each of the at least two phase masks modulating at least one of the spot size, beam tilt angle or directionality, and beam field of view of the light beam.

12. The beam carving assembly of claim 1, wherein: The phase distribution of the light beam is transformed based on a modulo 2π operation, wherein the modulo 2π phase shift is a function of the thickness of the core in a phase mask unit cell.

13. The beam carving assembly of claim 1, wherein: The at least one phase mask includes periodically placed unit cells, each unit cell having a corresponding core of non-uniform height.

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