A grid optimization method for a disordered hyperuniform solid device

Abstract

The present invention discloses a grid optimization method for a disordered super-uniform solid device, comprising: firstly, designing a base point region; secondly, inserting regularly distributed base points within the base point region; thirdly, generating a random point distribution outside the base point region and performing point optimization to obtain a disordered super-uniform point distribution; thereafter, performing triangulation on the regular point distribution to form regularly distributed lattice points within the base point region; performing triangulation on the disordered super-uniform point distribution to obtain lattice points of the mesh structure of the disordered super-uniform solid device; then, connecting adjacent lattice points among all lattice points to form grid walls, constructing the disordered super-uniform solid device, and completing grid optimization; finally, introducing waveguide defect lines into the disordered super-uniform solid device to construct a waveguide integrated device. The present invention regulates the boundary grid of the disordered super-uniform solid to generate regular grid walls, avoiding the generation of additional defect holes after introducing waveguide defect lines, thereby reducing the loss of the disordered super-uniform solid waveguide device and optimizing the photonic bandgap characteristics of the device.

Description

Technical Field

[0001] The present invention relates to the technical field of optoelectronic devices, and particularly relates to a method for optimizing the grid structure of a disordered hyperuniform solid device, so as to improve the photonic bandgap characteristics, optical loss, and processing error of an on-chip integrated disordered hyperuniform solid device. Background Art

[0002] In recent years, disordered hyperuniform solids, as an emerging artificial photonic bandgap structure, have received extensive attention. A disordered hyperuniform solid is a disordered structure, generally composed of a network structure formed by connecting points that satisfy hyperuniform disordered distribution in a two-dimensional plane or three-dimensional space. Different from traditional periodically arranged photonic crystals, disordered hyperuniform solids do not have long-range order, obvious repeatability, and periodicity as a whole. However, their hyperuniformity and short-range order enable them to still exhibit photonic bandgap characteristics and have unique advantages such as broadband complete photonic bandgap, isotropy, and broadband low dispersion. Disordered hyperuniform solids break the previous concept that only long-range ordered structures have photonic bandgaps, and can be used to develop optically compact devices with flexible light field transmission directions, and provide new ideas for solving the dilemmas faced by traditional artificial bandgap structures in applications involving wide wavelength bands and different polarization modes. So far, using the light field regulation ability of disordered hyperuniform solids, researchers have designed and manufactured various on-chip devices based on disordered hyperuniform solids. However, after introducing waveguide defect lines for on-chip device interconnection, the structure of disordered hyperuniform solids is damaged, resulting in problems such as deterioration of photonic bandgap characteristics, high optical loss, and large processing error in on-chip integrated disordered hyperuniform solid devices. Optimizing the structure of disordered hyperuniform solids and developing high-performance on-chip disordered hyperuniform solid waveguide devices are the basis for large-scale integration of disordered hyperuniform solid devices on chips.

[0003] In terms of papers, researchers have published many research results on improving the performance of on-chip integrated disordered hyperuniform solid waveguide devices. For example: In 2014, Milan M. et al. designed a disordered hyperuniform solid waveguide by inserting defect lines into a disordered hyperuniform solid in the communication band (11th International Conference on Group IV Photonics IEEE, 33 - 34, 2014), and found that the waveguide formed by introducing straight waveguide defect lines into the structure has lower optical loss than the waveguide formed by directly continuously filling the hole structure of the disordered hyperuniform solid. In 2019, Milan M. Others also designed a disordered hyperuniform solid waveguide device in the near-infrared (near-IR) band on a silicon-on-insulator wafer (Scientific Reports 9, 20338, 2019). By adjusting the angle between the waveguide defect line and the grid walls on both sides to be close to perpendicular, the optical loss of the disordered hyperuniform solid waveguide was further reduced. In 2023, Wan Dian et al. proposed a method for modifying the morphology of disordered hyperuniform solids. A 1.5 dB increase in transmittance could be achieved in a 10-μm-long disordered hyperuniform waveguide modified by a Bessel curve, and a 26% improvement in the quality factor was observed in a 2-μm-radius micro-ring modified by a Bessel curve, opening up a new way to optimize disordered hyperuniform devices. However, the above optimization methods have certain limitations. After introducing waveguide defect lines into the disordered network structure of disordered hyperuniform solids, the remaining defect holes on both sides of the waveguide defect lines perturb the optical properties of the structure and cause intense light scattering, resulting in the deterioration of the photonic bandgap characteristics and an increase in optical loss of the disordered hyperuniform waveguide device. In addition, these tiny irregular defect holes are difficult to fabricate precisely, which further increases the processing error of the disordered hyperuniform waveguide device.

[0004] In terms of patents, in 2017, Mullen Ruth Ann et al. of Etaphase Corporation applied for a US patent (US10031288B2) for a method for optimizing a disordered hyperuniform solid waveguide device. This method designed a disordered hyperuniform solid waveguide device by constructing a smooth ordered transition region composed of periodic or quasi-periodic structures between the disordered hyperuniform solid and the waveguide. However, the ordered transition region in this method affects the interaction between the optical fields in the disordered hyperuniform solid and the waveguide, resulting in the deterioration of the photonic bandgap characteristics. In 2023, Wan Dian et al. of Tianjin University applied for a Chinese patent (CN202310698203.1) for a method for optimizing disordered hyperuniform solid devices based on morphology modification. This patent adjusts the geometric morphology of disordered hyperuniform solid devices through curve functions or surface functions to optimize the photonic bandgap and optical loss characteristics of disordered hyperuniform solid devices. However, since the morphology modification method does not consider the performance deterioration caused by introducing waveguide defect lines into disordered hyperuniform solids, the optimization effect of this method on the optical loss in disordered hyperuniform solid waveguide integrated devices is limited.

[0005] In summary, although the research on disordered hyperuniform solids has developed rapidly in recent years, the disordered grid structure of disordered hyperuniform solids will form a large number of defect holes after introducing waveguide defect lines, resulting in problems such as photon bandgap distortion, high optical loss, and large processing errors in disordered hyperuniform solid waveguide devices. This makes it difficult for on-chip disordered hyperuniform solid devices to be interconnected with other on-chip devices through waveguides, which hinders the application of disordered hyperuniform solids in large-scale on-chip integration. Developing a method that can effectively optimize the grid structure of disordered hyperuniform solids to improve the photon bandgap characteristics, optical loss, and processing errors of disordered hyperuniform solid waveguide devices has high practical application value. Summary of the Invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a method for optimizing the grid structure of disordered hyperuniform solid devices and thereby improving the photon bandgap, optical loss, and processing errors of disordered hyperuniform solid waveguide devices.

[0007] The purpose of the present invention is achieved through the following technical solutions:

[0008] A grid optimization method for disordered hyperuniform solid devices, which generates regular grid walls by regulating the boundary grids of disordered hyperuniform solid devices, avoids the generation of additional defect holes after inserting waveguide defect lines, and optimizes the photon bandgap characteristics of disordered hyperuniform solid devices. The method specifically includes the following steps:

[0009] (1) Design a base point region;

[0010] (2) Insert regularly distributed base points within the base point region to obtain a regular point distribution;

[0011] (3) Generate a random point distribution outside the base point region and perform point optimization to obtain a disordered hyperuniform point distribution;

[0012] (4) Perform triangulation on the regular point distribution to form regularly distributed lattice points within the base point region; perform triangulation on the disordered hyperuniform point distribution to obtain the lattice points of the network structure of the disordered hyperuniform solid device;

[0013] (5) Connect adjacent lattice points among all lattice points to form grid walls. The grid walls include several hole structures, and a disordered hyperuniform solid device is constructed. The disordered hyperuniform solid device has regular hole structures that can be completely covered by waveguide defect lines, completing the grid optimization;

[0014] (6) Construct a waveguide integrated device by introducing waveguide defect lines into the disordered hyperuniform solid device.

[0015] Furthermore, the waveguide defect line is any number of linear shapes formed by one or a combination of straight lines, circular arcs, elliptical arcs, Euler curves, Bessel curves, and Gaussian curves with arbitrary orientations.

[0016] Furthermore, the regularly distributed base points are distributed on any number of linear shapes formed by one or a combination of straight lines, circular arcs, elliptical arcs, Euler curves, Bessel curves, and Gaussian curves.

[0017] Furthermore, the grid wall material is any one of silicon, germanium, silicon-germanium alloy, silicon nitride, lithium niobate, and sulfide.

[0018] Furthermore, the hole structure is filled with one or a combination of air, silicon dioxide, and silicon nitride.

[0019] Furthermore, the disordered hyperuniform solid device is a two-dimensional planar structure or a three-dimensional solid structure.

[0020] Furthermore, the operating wavelength of the disordered hyperuniform solid device is in the microwave, THz wave, mid-infrared band, or near-infrared band.

[0021] Furthermore, the formed regular grid walls can be distributed on the boundary of the disordered hyperuniform solid device; they can also be distributed at any position within the disordered hyperuniform solid device.

[0022] Furthermore, the formed regular grid walls can be distributed along any number of linear shapes formed by one or a combination of straight lines, circular arcs, elliptical arcs, Euler curves, Bessel curves, and Gaussian curves with arbitrary orientations.

[0023] Furthermore, the shape of the grid wall can be a simple polygon or a composite shape formed by one or a combination of straight lines, circular arcs, elliptical arcs, Euler curves, Bessel curves, and Gaussian curves.

[0024] Compared with the prior art, the beneficial effects brought by the technical solution of the present invention are:

[0025] (1) Compared with the existing optimization methods that adjust the angles of the disordered hyperuniform solid grid walls on both sides of the waveguide defect line and replace the disordered hyperuniform solid grid walls on both sides with periodic or quasi-periodic smooth ordered transition regions, the grid-optimized disordered hyperuniform solid waveguide device proposed by the present invention can have better photonic bandgap performance and optical field regulation ability under the condition that the optical field in the waveguide fully interacts with the disordered hyperuniform solid. Adjusting the angle between the waveguide defect line and the grid walls on both sides to be close to perpendicular to reduce optical loss will cause an exacerbation of the photonic bandgap distortion, resulting in the degradation of the photonic bandgap performance of the waveguide device. After replacing the disordered hyperuniform solid grid walls on both sides with periodic or quasi-periodic smooth ordered transition regions, the interaction between the smooth ordered transition region and the optical field in the waveguide is strong, while the interaction between the optical field and the disordered hyperuniform solid is weakened, causing the degradation of the photonic bandgap performance of the waveguide device. By forming a regular grid wall structure, the present invention can avoid the distortion of the bandgap of the disordered hyperuniform solid without replacing the disordered hyperuniform solid grid walls on both sides with smooth ordered transition regions, so that the disordered hyperuniform solid waveguide device has complete photonic bandgap performance and stronger optical field regulation ability in a wider wavelength band.

[0026] (2) Compared with the existing topography modification optimization methods, the grid optimization method proposed by the present invention has lower optical loss. The existing topography modification methods only perform Bessel curve modification on the holes during design and do not consider the generation of irregular defect holes after introducing waveguide defect lines into the disordered hyperuniform solid, resulting in limited optical loss reduction effect of the method for optimizing disordered hyperuniform solid waveguide integrated devices. The present invention regulates the disordered grid wall structure in the disordered hyperuniform solid, avoids the generation of additional defect holes after introducing waveguide defect lines, and further reduces the optical loss of the disordered hyperuniform solid waveguide device.

[0027] (3) The fabrication of the disordered hyperuniform solid device based on grid optimization has a higher degree of match with the multi-project wafer process, avoids the generation of irregular defect holes when introducing waveguide defect lines, thus avoiding tiny and complex structures that are difficult to process, reducing processing errors, being beneficial to the development of low-cost, high-quality, high-density integrated disordered hyperuniform solid integrated photonic circuits, and being beneficial to the realization of high-performance large-scale on-chip integrated devices.

[0028] (4) The technical solution of the present invention provides a higher degree of design freedom for the structural design of disordered hyperuniform solid devices. By forming a regular grid wall structure in the disordered hyperuniform solid, the generation of additional irregular defect holes after introducing specific defects in the on-chip device design is avoided, and the influence of the additional irregular defect holes on the on-chip device design is circumvented, enabling the disordered hyperuniform solid to perform on-chip device design with a higher degree of freedom while maintaining the device performance.

[0029] (5) The solution of the present invention is applicable to the design of disordered hyperuniform solid devices for various applications, with wide applicability. It can not only be applied to the design of on-chip disordered hyperuniform solid waveguides, but also to the design of on-chip integrated devices such as polarizers, filters, microcavities, lasers, and sensors. It can also be used for the design of off-chip integrated devices such as metasurfaces and light trapping plates, opening up a new way for the development of disordered hyperuniform solid devices for applications such as signal processing, nonlinearity, and sensing. Description of the Drawings

[0030] Figure 1 It is a design method diagram of the present invention.

[0031] Figure 2 and Figure 3 are respectively images of the disordered hyperuniform solid waveguide after grid optimization and without grid optimization in Specific Embodiment 1 of the present invention.

[0032] Figure 4 and Figure 5 are respectively the simulation results and experimental results of the transmission spectra of the disordered hyperuniform solid waveguide after grid optimization and without grid optimization in Specific Embodiment 1 of the present invention.

[0033] Figure 6 It is an image of the disordered hyperuniform solid defect cavity after grid optimization in Specific Embodiment 2 of the present invention.

[0034] Figure 7 and Figure 8 are respectively the simulation results and measurement results of the disordered hyperuniform solid defect cavity after grid optimization in Specific Embodiment 2 of the present invention. Detailed Description of the Embodiments

[0035] The present invention will be further described in detail below with reference to the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] Figure 1Shown is a grid optimization method for a disordered hyperuniform solid device protected by the present invention. When the waveguide defect line is a straight line, the base point region is designed as a rectangle located at the upper and lower boundaries of the point distribution. Base points are inserted at equal intervals along two rows respectively, and then a random point distribution is generated outside the base point region and point optimization is carried out to generate a disordered hyperuniform point distribution. Further, after triangulation, irregular lattice points are generated outside the base point region and regular lattice points are generated inside the base point region, so as to generate a regular grid structure at the boundary of the constructed disordered hyperuniform solid that can be completely covered by the waveguide defect line. Finally, in the disordered hyperuniform solid waveguide constructed by introducing a waveguide defect line into the center of a 2×2 disordered hyperuniform solid array, the generation of irregular defect holes is avoided, thereby optimizing the photonic bandgap characteristics, optical loss and processing error of the waveguide. The optimization method is as follows:

[0037] S1. Design the base point region;

[0038] S2. Insert regularly distributed base points into the base point region in the point distribution to obtain a regular point distribution;

[0039] S3. Generate a random point distribution outside the base point region and carry out point optimization to obtain a disordered hyperuniform point distribution;

[0040] S4. Triangulate the regular point distribution to form regularly distributed lattice points in the base point region; triangulate the disordered hyperuniform point distribution to obtain the lattice points of the mesh structure of the disordered hyperuniform solid device;

[0041] S5. Connect adjacent lattice points among all lattice points to form grid walls. The grid walls include several hole structures. Construct a disordered hyperuniform solid device. The disordered hyperuniform solid device has a regular hole structure that can be completely covered by the waveguide defect line, and other hole structures do not overlap with the waveguide defect line region, completing the grid optimization;

[0042] S6. Construct a waveguide integrated device by introducing a waveguide defect line into the disordered hyperuniform solid device.

[0043] Example 1

[0044] Figure 2 Shown is the disordered hyperuniform solid waveguide after grid optimization. The enlarged part shows that a straight waveguide defect line is introduced into the disordered hyperuniform solid after grid optimization. Its design parameters are as follows: Three rows of base points are symmetrically inserted along the center line of the waveguide defect line and are evenly distributed in a straight line parallel to the waveguide defect line. The lateral spacing of the evenly distributed base points in the same row is 0.82 μm, and the longitudinal and lateral spacings of adjacent base points across rows are 0.41 μm and 0.82 μm respectively. The waveguide width is 0.8 μm, the length is 36 μm, the period of the disordered hyperuniform solid is 9 μm, the wall width is 0.25 μm, and the Bessel modification weight is 1. Figure 3Shown is a disordered hyperuniform solid waveguide device without mesh optimization under the same design parameters. The enlarged part shows that a waveguide defect line is directly introduced into the unoptimized disordered hyperuniform solid. There are many irregular defect holes at the junction of the waveguide boundary and the disordered hyperuniform solid, which will cause distortion of the photonic bandgap and increase the loss and degrade the performance of the disordered hyperuniform waveguide device.

[0045] Figure 4 Shown are the simulation results and experimental results of the transmission spectrum of the disordered hyperuniform solid waveguide device after mesh optimization. The dashed line is the simulation result, and the solid line is the experimental result. The experimental results show that the disordered hyperuniform solid waveguide after mesh optimization has an ultra-wide 3dB bandwidth of 2.13 - 2.375μm, and has a flat transmission spectrum in the wavelength range of 2.22 - 2.35μm, demonstrating the complete broadband photonic bandgap characteristics, with an average transmittance of -2.8dB. Figure 5 Shown are the simulation results and experimental results of the transmission spectrum of the disordered hyperuniform solid waveguide device without mesh optimization. The dashed line is the simulation result, and the solid line is the experimental result. The experimental results show that the 3dB bandwidth passband of this waveguide is 2.10 - 2.18μm, and there is a serious drop in transmittance at 2.22 - 2.29μm. The transmission spectrum fluctuates greatly and is not complete, and the transmittance is low, with an average transmittance of -5.8dB. Compared with the unoptimized disordered hyperuniform waveguide, the transmittance of the disordered hyperuniform waveguide after mesh optimization is increased by 3.0dB. In addition, the experimental transmission spectrum of the disordered hyperuniform solid waveguide after mesh optimization is in good agreement with the simulation transmission spectrum because mesh optimization eliminates irregular defect holes, thus avoiding difficult-to-process tiny complex structures and reducing the processing error of the device. Therefore, the disordered hyperuniform waveguide after mesh optimization has a more complete photonic bandgap, lower optical loss, and processing error.

[0046] Finally, the method of this embodiment is only a preferred implementation, and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0047] Embodiment 2

[0048] Figure 6The figure shows a disordered hyperuniform solid defect cavity after lattice optimization, which is formed by introducing three collinear straight waveguide defect lines in a disordered hyperuniform solid through lattice optimization. Its design parameters are as follows: Three rows of base points are symmetrically inserted along the waveguide defect line as the center line, and the base points are uniformly distributed linearly in the direction parallel to the waveguide defect line. The lateral spacing of the uniformly distributed base points in the same row is 0.82 μm, and the longitudinal and lateral spacings of adjacent base points in different rows are 0.41 μm and 0.82 μm respectively. The waveguide width is 0.8 μm, the length of the defect cavity (the length of the central waveguide defect line) is 1.1 μm, the distance between the inner end faces of the two side waveguide defect lines and the adjacent end faces of the central waveguide defect line is 1.4 μm, the period of the disordered hyperuniform solid is 9 μm, the wall width is 0.25 μm, and the Bessel modification weight is 1.

[0049] Figure 7 The figure shows the simulation results of the disordered hyperuniform solid defect cavity after lattice optimization. The simulation results show that the full width at half maximum of the disordered hyperuniform solid defect cavity after lattice optimization is about 32.4 nm, the Q value is about 70, and the peak transmittance is 0.36. Figure 8 The figure shows the measurement results of the disordered hyperuniform solid defect cavity after lattice optimization. The full width at half maximum of the disordered hyperuniform solid defect cavity obtained experimentally after lattice optimization is about 32.1 nm, the Q value is about 70, and the peak transmittance is 0.35, showing good consistency with the simulation results. This is because lattice optimization avoids the additional processing errors caused by irregular defect holes, so that the disordered hyperuniform solid defect cavity has a high processing tolerance. In addition, thanks to the fact that lattice optimization avoids the generation of additional defect holes, the disordered hyperuniform solid defect cavity will not show distortion of the transmittance spectrum due to the excitation of additional modes by light in the irregular defect holes, but shows an ideal complete Gaussian-shaped transmittance spectrum. Therefore, the disordered hyperuniform defect cavity after lattice optimization has good processing tolerance and transmittance spectrum characteristics.

[0050] Finally, the method of this embodiment is only a preferred implementation scheme and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

[0051] The present invention is not limited to the embodiments described above. The above description of the specific embodiments is intended to describe and illustrate the technical solutions of the present invention. The above specific embodiments are only illustrative and not restrictive. Without departing from the spirit of the present invention and the scope protected by the claims, those of ordinary skill in the art can make many specific transformations in various forms under the inspiration of the present invention, and these all belong to the protection scope of the present invention.

Claims

1. A grid optimization method for a disordered hyperuniform solid device, characterized in that By regulating the boundary grid of the disordered hyperuniform solid device to generate a regular grid structure, the generation of additional defect holes after inserting waveguide defect lines is avoided, and the photonic bandgap characteristics of the disordered hyperuniform solid device are optimized. The specific steps are as follows: (1) Design a base point area; (2) Insert regularly distributed base points in the base point area to obtain a regular point distribution; (3) Generate a random point distribution outside the base point area and perform point optimization to obtain a disordered hyperuniform point distribution; (4) Triangulate the regular point distribution to form regularly distributed lattice points in the base point area; triangulate the disordered hyperuniform point distribution to obtain the lattice points of the mesh structure of the disordered hyperuniform solid device; (5) Connect adjacent lattice points among all lattice points to form grid walls, and there are several hole structures on the grid walls to construct a disordered hyperuniform solid device. There is a regular hole structure in the disordered hyperuniform solid device that can be completely covered by waveguide defect lines, and the grid optimization is completed; (6) Construct a waveguide integrated device by introducing waveguide defect lines into the disordered hyperuniform solid device.

2. The grid optimization method of the disordered hyperuniform solid device according to claim 1, characterized in that The waveguide defect line is any number of linear shapes composed of one or several combinations of straight lines, circular arcs, elliptical arcs, Euler curves, Bessel curves, and Gaussian curves with arbitrary orientations.

3. The grid optimization method of the disordered hyperuniform solid device according to claim 1, characterized in that The regularly distributed base points are distributed on any number of linear shapes composed of one or several combinations of straight lines, circular arcs, elliptical arcs, Euler curves, Bessel curves, and Gaussian curves.

4. The grid optimization method for the disordered hyperuniform solid according to claim 1, characterized in that The material of the grid wall is any one of silicon, germanium, silicon-germanium alloy, silicon nitride, lithium niobate, and sulfide.

5. The grid optimization method for disordered hyperuniform solids according to claim 1, characterized in that The hole structure is filled with one or several of air, silicon dioxide, and silicon nitride.

6. The grid optimization method for the disordered hyperuniform solid according to claim 1, wherein The disordered hyperuniform solid device is a two-dimensional planar structure or a three-dimensional solid structure.

7. The grid optimization method for the disordered hyperuniform solid according to claim 1, wherein The working wavelength of the disordered hyperuniform solid device is in the microwave, THz wave, mid-infrared band, or near-infrared band.

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