An optical phased array waveguide array

Abstract

The application discloses an optical phased array waveguide array, which comprises a plurality of alternately arranged waveguides and interval layers, and antennas integrated on the interval layers. Compared with the prior art, the waveguide array of the application rationally utilizes the space of an optical phased array chip, and the interval layer integrated with the antennas is arranged in the waveguide interval. The interval layer not only bears the function of directing the outgoing light beam, but also reduces the crosstalk between channels, which helps to realize the optical phased array with a large effective field of view, a small light beam divergence angle and low crosstalk between channels. The structural design of the application supports the realization of the structures of the waveguide array on the same layer of the chip by using the same material and the same etching depth, and the process is simple and stable, and the cost performance is high.

Description

Technical Field

[0001] This invention relates to the field of optoelectronics technology, and more particularly to an optical phased array waveguide array. Background Technology

[0002] Optical phased arrays are a type of optical integrated device that achieves directional emission, scanning, or reception of light beams by controlling the phase between each channel. Waveguide arrays containing antennas are an important component of optical phased arrays, used to directionally emit light beams.

[0003] Generally, to direct the guided wavelight within a chip into spatial light outside the chip, an antenna structure within the waveguide array is required. This antenna structure is typically located on the surface, sides, or ends of each waveguide, or adjacent to the waveguide. In practical applications, to ensure the emitted beam has the smallest possible divergence angle and the largest possible effective field of view in the scanning direction, the waveguides and antennas in the waveguide array must be arranged compactly. However, dielectric waveguides do not completely confine the light field within the waveguide core; a portion of the light field is distributed around the waveguide as evanescent waves. This phenomenon is particularly pronounced in waveguides with subwavelength characteristic dimensions. When the waveguides are arranged compactly, these evanescent waves may enter adjacent waveguides, causing amplitude / phase disturbances in the light field within each channel and resulting in severe crosstalk. Specifically, when the antenna radiates the guided wavelight into space, the emitted light may also enter other channels, further exacerbating crosstalk. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides an optical phased array waveguide array. To provide a basic understanding of some aspects of the disclosed embodiments, a brief summary is given below. This summary is not intended as a general description, nor is it intended to identify key / important components or to define the scope of protection of these embodiments. Its sole purpose is to present some concepts in a simple form as a prelude to the detailed description that follows.

[0005] The present invention adopts the following technical solution:

[0006] The present invention provides an optical phased array waveguide array, which includes: a plurality of alternately arranged waveguides and spacer layers, wherein an antenna is integrated on the spacer layer.

[0007] Furthermore, the spacer layer includes at least one subwavelength thin layer, and the subwavelength thin layer is arranged to extend along the light guiding direction of the waveguide array.

[0008] Furthermore, the antenna is integrated on a subwavelength thin layer adjacent to the waveguide and on the side facing the waveguide.

[0009] Furthermore, the antenna is composed of periodic, quasi-periodic, or aperiodic scattering structures.

[0010] Furthermore, the spacer layers located at the edges of the waveguide array include a subwavelength thin layer, and the subwavelength thin layer at the edge has an antenna integrated on the side facing the waveguide.

[0011] The beneficial effects of this invention are as follows:

[0012] 1. The present invention integrates the antenna within the spacer layer. Compared with the existing solutions, the waveguide array proposed in this invention makes reasonable use of the space of the optical phased array chip. The spacer layer with integrated antenna is set within the waveguide spacer, which not only undertakes the function of directional beam emission, but also reduces crosstalk between channels. This helps to achieve an optical phased array with a large effective field of view, a small beam divergence angle, and low crosstalk between channels.

[0013] 2. The structural design of this invention supports the realization of each structure of the waveguide array in the same layer of the chip with the same material and the same etching depth, which is simple and stable in process and has high cost performance. Attached Figure Description

[0014] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 This is a schematic diagram of the optical phased array waveguide array of the present invention;

[0016] Figure 2 This is a schematic diagram of one possible configuration of the spacer layer located at a non-edge position in this invention;

[0017] Figure 3 This is a schematic diagram of another configuration of the spacer layer located at a non-edge position in the present invention;

[0018] Figure 4 This is a schematic diagram illustrating the configuration of the spacer layer located at the edge position in this invention. Detailed Implementation

[0019] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be understood that the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0020] like Figure 1-4As shown, the present invention provides an optical phased array waveguide array. In the various figures of the present invention, a solid box represents a specific structural unit, such as a waveguide, a subwavelength thin layer, a chainsaw-like structure integrated from a subwavelength thin layer and multiple antennas, etc.; a dashed box represents a component with complete functionality, which may contain one or a series of specific structures.

[0021] The waveguide array 10 of the present invention specifically includes: a plurality of alternately arranged waveguides 1 and spacer layers 2.

[0022] Waveguide 1 connects the pre-amplifier structure 3 and the post-amplifier structure 4. Input light propagates as guided wavelight within the channel formed by the waveguides. The pre-amplifier structure 3 has functions such as beam splitting, polarization control, amplitude modulation, and phase modulation, while the post-amplifier structure 4 has functions such as measurement, feedback, and attenuation. In some optional embodiments, the post-amplifier structure 4 is not essential. The pre-amplifier structure 3 and post-amplifier structure 4 mentioned above are prior art and will not be described further in this invention.

[0023] Spacer layer 2 is used to radiate the guided light propagating in each channel of the waveguide array into space and to isolate crosstalk between channels.

[0024] An antenna 6 is integrated on the spacer layer 2. Specifically, the spacer layer 2 includes at least one subwavelength thin layer 5, which extends along the light guiding direction of the waveguide array. The antenna 6 is integrated on the subwavelength thin layer 5 adjacent to the waveguide 1, and is integrated on the side of the subwavelength thin layer 5 facing the waveguide 1.

[0025] like Figure 1 As shown, near each adjacent waveguide 1, there is a chainsaw-shaped structure 231, where an antenna 6 is combined with a subwavelength thin layer 5 to form a chainsaw-shaped structure 231. A subwavelength thin layer 5 is placed between two chainsaw-shaped structures 231, meaning there are three subwavelength thin layers 5 between two adjacent waveguides 1. Antennas 6 are integrated only on the subwavelength thin layer 5 adjacent to waveguide 1, and on the side facing waveguide 1. To improve isolation, several subwavelength thin layers 5 can be placed between two chainsaw-shaped structures 231. The antennas 6 scatter the evanescent waves distributed around the adjacent waveguides 1, ultimately directing the guided light into space. The subwavelength thin layers 5 limit the range of the evanescent waves and reduce the amount of emitted light entering the waveguides that guide other channels, thus suppressing crosstalk. Figure 1 As shown, on one side of waveguide 1 near the edge, there is a structure 21 in which a series of waveguides 1 and spacer layers 2 are arranged alternately.

[0026] like Figure 2As shown, one configuration of the spacer layer located at a non-edge position is illustrated, comprising two chainsaw-shaped structures 231. These can be considered as two subwavelength thin layers 5 forming the spacer layer, with the antenna 6 integrated on the side of the subwavelength thin layer 5 facing the waveguide 1. No other subwavelength thin layers are arranged between the two chainsaw-shaped structures 231. This configuration is suitable for applications requiring reduced waveguide spacing, compared to... Figure 1 The configuration shown in the figure improves the integration density of the waveguide array, increases the effective field of view, and reduces the beam divergence angle.

[0027] like Figure 3 As shown, another configuration of the spacer layer located at a non-edge position is illustrated, comprising a double-sided chainsaw-like structure 234, which can be considered as a subwavelength thin layer 5 forming the spacer layer. Antennas 6 are integrated on both sides of the subwavelength thin layer 5, suitable for applications requiring further reduction in waveguide spacing. Compared to... Figure 2 The configuration shown further improves the integration density of the waveguide array, increases the effective field of view, and reduces the beam divergence angle.

[0028] In the above text, non-edge position means that waveguides are provided on both sides of spacer layer 2. Correspondingly, spacer layer located at the edge position means that the current spacer layer has waveguides arranged on only one side, and the other side is the edge of the waveguide array. That is, both sides of the waveguide array are edged by a spacer layer, and its structure is different from that of the spacer layer located at the non-edge position of the array.

[0029] like Figure 4 As shown, the configuration of the spacer layer located at the edge is highlighted. The spacer layer located at the edges of the waveguide array includes a subwavelength thin layer 5, and the subwavelength thin layer 5 at the edge integrates an antenna 6 on the side facing the waveguide 1. Specifically, a chainsaw-shaped structure 231 is provided on each side of the alternating waveguide spacer layer structure 25, which can be regarded as a set of antennas and a set of subwavelength thin layers. In this case, the chainsaw-shaped structure is used instead of the antenna without a spacer layer in order to improve the symmetry of the scattering of the guided wave light in the optical channel guided by the edge waveguide.

[0030] The waveguide spacer alternating structure 25 refers to the structure in which waveguide 1 and spacer 2 are arranged alternately. The spacer 2 in the waveguide spacer alternating structure 25 is the spacer located at a non-edge position.

[0031] This invention does not limit the specific number of spacer layer 2 and waveguide 1, but generally the number of waveguides in an optical phased array should be greater than 4.

[0032] Antenna 6 consists of periodic, quasi-periodic, or aperiodic scattering structures. Specifically, antenna 6 can be a periodic structure designed based on Bragg scattering conditions, or a quasi-periodic or aperiodic structure designed using optimization algorithms. The geometry of antenna 6 includes, but is not limited to, common geometric structures such as cuboids and cylinders, or other shapes obtained according to optimization algorithms that simultaneously possess reasonable manufacturability and scattering function, or can be implemented using alternating combinations of different materials to form a grid. Furthermore, antennas in different spacing layers, or two sets of antennas in the same spacing layer, can be implemented using the same method and structural parameters, or they can be implemented using different methods or different structural parameters. Considering that the cuboid is an antenna geometry design that has been tested in various photonic integrated device designs and is easy to combine with subwavelength thin layers, this invention preferably describes a cuboid antenna and a chainsaw-like structure composed of a cuboid antenna and a subwavelength thin layer, but it should not be considered that designs using other antenna configurations deviate from the scope of protection of this patent.

[0033] The optical phased array waveguide array described above can be implemented on various common chip platforms, including but not limited to silicon, silicon nitride, lithium niobate, polymers, etc. Furthermore, the waveguides used can be strip-shaped, ridge-shaped, composite-structured, etc. Preferably, considering the simplicity of fabrication, waveguides, antennas, and subwavelength thin layers of the same height can be fabricated on a dielectric material layer of the same height using a single "photolithography-etching" process. However, in the optical phased array waveguide array proposed in this invention, the waveguides, antennas, spacers, and other substructures can also be made of different materials, have different heights, or have different etching depths corresponding to each substructure. While this invention preferably describes multiple waveguides arranged in a one-dimensional array, it should not be considered that selecting other waveguide combination forms, such as two-dimensional arrangements, ring arrangements, star arrangements, etc., deviates from the scope of protection of this patent.

[0034] The path of guided light in a waveguide array is not limited to the interior of each waveguide, but also includes the area surrounding each waveguide. Generally, most of the energy is concentrated inside the waveguide, while a small portion is distributed outside. The portion of the guided light distributed outside the dielectric waveguide is called the evanescent wave. The intensity of the evanescent wave decreases with increasing spatial distance from the waveguide. Without special design, the evanescent wave is mainly distributed within one to several wavelengths of the vicinity of the waveguide. When there are other waveguides within this distance, the evanescent wave may couple into those waveguides, causing crosstalk between channels and affecting the performance of the optical phased array. When there are structures that can disturb the optical field, such as scatterers, within this distance, these structures can scatter the evanescent wave into space, radiating the guided light into space. This radiated spatial light, when entering other waveguides, can also cause crosstalk between channels. Through a reasonable design, the present invention introduces a spacer layer 2 between waveguides 1, so that waveguides 1 and spacer layer 2 form an alternating structure, and integrates an antenna 6 on the subwavelength thin layer 5 of spacer layer 2. The antenna 6 realizes the directional emission of guided light, that is, the antenna 6 scatters the evanescent waves on both sides of the waveguide in each adjacent channel, and the subwavelength thin layer 5 suppresses the crosstalk between channels caused by evanescent waves and emitted light.

[0035] This invention reduces the spacing between waveguides in the waveguide array while strictly controlling crosstalk between channels. The antenna is compactly integrated on the spacer layer 2 surrounding waveguide 1. This not only fully utilizes the space on the chip to compactly arrange functional units, facilitating a large effective field of view and a small beam divergence angle in the beam scanning direction, but also features complete separation between antenna 6 and waveguide 1, ensuring that antenna 6 only acts on the evanescent wave. This allows for precise control of the optical attenuation coefficient of the waveguide array, potentially enabling ultra-long waveguide arrays and further reducing the beam divergence angle perpendicular to the scanning direction. Furthermore, this invention has a simple structure, and the waveguide array can be fabricated using mature and stable processes without increasing the chip fabrication process steps or manufacturing difficulty. Moreover, it meets performance requirements without interfering with the normal operation of other modules in the optical phased array.

[0036] The structural design of this invention achieves compact integration of multiple structural modules on an optical phased array waveguide array. Compared with existing solutions, it has the potential to achieve an optical phased array with a larger effective field of view, a smaller beam divergence angle, and lower inter-channel crosstalk. Furthermore, since the waveguide and spacer layer are located on the same layer of the chip, they can be fabricated using the same process as traditional optical phased array chips. The addition of a spacer layer or the integration of an antenna on the spacer layer does not increase the number of photolithography and etching processes required for fabricating the optical phased array chip. This provides a simple and low-cost method for realizing optical phased array waveguide arrays, showing promising application prospects in fields such as autonomous driving, industrial robots, free-space optical communication, and holographic displays.

[0037] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An optical phased array waveguide array, characterized in that, The waveguide array includes: several alternating waveguides and spacer layers, and an antenna is integrated on the spacer layer; The spacer layer is located at a non-edge position of the waveguide, and the spacer layer at the non-edge position includes at least two subwavelength thin layers, which are arranged to extend along the light guiding direction of the waveguide array; the antenna is integrated on the subwavelength thin layer adjacent to the waveguide and is integrated on the side facing the waveguide.

2. The optical phased array waveguide array according to claim 1, characterized in that, It also includes a spacer layer located at the edge of the waveguide, the spacer layer at the edge comprising: a subwavelength thin layer, the subwavelength thin layer being arranged to extend along the light guiding direction of the waveguide array; the antenna is integrated on the subwavelength thin layer and integrated on the side facing the waveguide.

3. The optical phased array waveguide array according to claim 1, characterized in that, The antenna consists of periodic, quasi-periodic, or aperiodic scattering structures.

4. An optical phased array waveguide array according to claim 3, characterized in that, The spacer layer located at the edges of the waveguide array includes a subwavelength thin layer, and the subwavelength thin layer at the edge has an antenna integrated on the side facing the waveguide.

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