A method for optimizing disordered ultra-uniform solid devices based on morphology modification

Abstract

The present invention discloses a method for optimizing disordered ultra-uniform solid devices based on morphology modification, which adjusts the geometric morphology of disordered ultra-uniform solids through curve functions or surface functions, thereby optimizing the photonic band gap and optical loss characteristics of disordered ultra-uniform solid devices. First, several points on the boundary between the hole and the grid wall in the disordered ultra-uniform solid are selected; second, the selected points are connected and smoothed using the curve function or the surface function; finally, the boundary of the original disordered ultra-uniform solid is replaced by the smoothed curve to complete the adjustment of its geometric morphology.

Description

Technical Field

[0001] The invention relates to the technical field of optoelectronic devices, and in particular to a method for improving the photon band gap and optical loss of a disordered ultra-uniform solid device based on a device morphology modification technology. Background Art

[0002] In recent years, hyperuniform disordered solids have attracted great attention as an emerging artificial photonic bandgap structure. The network structure of a hyperuniform disordered solid is generally constructed by points that satisfy hyperuniform disordered distribution in a two-dimensional plane or three-dimensional space, and the grid wall and the filling hole are made of dielectric materials with different refractive indices. Among them, the points that satisfy the hyperuniform disordered distribution have short-range order characteristics, that is, the average spacing between points in the structure is relatively fixed. Past studies have shown that this short-range order characteristic can make the hyperuniform disordered solid have a wide spectrum and isotropic complete photonic bandgap, and at the same time, it has the advantages of being insensitive to polarization and temperature changes. Based on the above photonic bandgap characteristics, hyperuniform disordered solids can be used to develop optical devices with compact structure, flexible light field transmission direction, and insensitive to ambient temperature changes. So far, researchers have designed and manufactured a variety of optical devices based on hyperuniform disordered solids, including waveguides, resonant cavities, polarizers, stealth devices, lasers, etc. Among them, optimizing the photonic bandgap of hyperuniform disordered solids is the key to the development of the above devices.

[0003] In terms of papers, researchers have proposed methods based on point distribution optimization and structural coefficient optimization, and published a number of research results. For example, in 2009, Marian Florescu et al. proved through the structural factor of super-uniformity that the super-uniformity of point distribution in disordered super-uniform solids directly affects the size of their photonic band gap (Proceedings of the National Academy of Sciences, 106, 49, 20658). In addition, researchers have also optimized the photonic band gap of disordered super-uniform solids by changing structural parameters such as the number of unit points, network wall width and structure height. In 2014, Weining Man et al. realized a disordered super-uniform solid with a photonic band gap of about 100nm in the near-infrared band on a silicon-on-insulator wafer. Its average lattice constant is 499nm, the network wall width is 150nm, and the height is 220nm (11th International Conference on Group IV Photonics IEEE, 33-34, 2014). However, the above optimization methods have certain limitations. For example, the point distribution optimization method takes a long time to generate a multi-point system, and the structural coefficient optimization method has limited ability to expand the photonic band gap. In addition, the optical loss of the disordered ultra-uniform solid waveguide device developed based on the above method is still high.

[0004] In terms of patents, in 2018, Steinhardt Paul J et al. from Princeton University applied for a US patent for a disordered ultra-uniform solid and its preparation method (US201815965206). The patent uses an annealing algorithm to control the ultra-uniformity of the disordered structure to optimize the photonic band gap. In 2015, Mullen Ruth Ann et al. from Etaphase applied for a US patent for a disordered ultra-uniform solid (US201615280150). The structure can adjust the photonic band gap by controlling the width of the grid wall. At present, there is no application for related patents in China.

[0005] In summary, although the research on disordered ultra-uniform solids has developed rapidly in recent years, the technology for optimizing the photonic band gap still has many shortcomings, which affects the application of disordered ultra-uniform solids in photonic devices. It is very meaningful to develop a method that can efficiently and quickly optimize disordered ultra-uniform solids, effectively broaden the photonic band gap of the device, and reduce the optical loss of disordered ultra-uniform structures. Summary of the invention

[0006] The purpose of the present invention is to overcome the deficiencies in the prior art and to provide a method for improving the photonic band gap and optical loss of disordered ultra-uniform solid devices based on device morphology modification technology.

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

[0008] A method for optimizing disordered ultra-uniform solid devices based on morphology modification is provided. The geometric morphology of the disordered ultra-uniform solid device is adjusted by a curve function or a surface function to optimize the photonic band gap and optical loss characteristics of the solid device. The specific steps are as follows:

[0009] (1) Selecting several points on the boundary between the hole and the grid wall in the disordered ultra-uniform solid device;

[0010] (2) Connect and smooth the selected points using curve functions or surface functions;

[0011] (3) The boundary of the original disordered ultra-uniform solid is replaced by a smoothed curve or surface to complete the adjustment of its geometric morphology.

[0012] Furthermore, the grid wall is made of one of silicon, silicon dioxide, germanium, silicon-germanium alloy, silicon nitride, lithium niobate, and sulfide.

[0013] Furthermore, the holes are filled with one or more of air, silicon dioxide, and silicon nitride.

[0014] Furthermore, the disordered ultra-uniform solid device is a two-dimensional planar structure or a three-dimensional structure.

[0015] Furthermore, the curve function is a combination of one or more of a Bezier curve, an Euler curve, an Euler torus curve, and a quadratic curve, and the surface function is a combination of one or more of a Bezier surface, a bi-arc surface, and a quadratic surface.

[0016] Furthermore, the operating wavelength of the disordered ultra-uniform solid device is microwave, THz wave, mid-infrared band or near-infrared band.

[0017] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0018] (1) Compared with unmodified disordered ultra-uniform solids, the present invention can significantly widen the photonic band gap, optimize the light field confinement capability, and reduce light scattering optical loss by changing the morphology of the disordered ultra-uniform structure, thereby reducing the optical loss of the disordered ultra-uniform solid device.

[0019] (2) The method for making disordered ultra-uniform solid devices based on morphology modification of the present invention has a higher degree of compatibility with the multi-project wafer process and a higher tolerance to processing errors, which is conducive to the development of low-cost, high-quality, high-density integrated disordered ultra-uniform solid integrated photonic circuits and the realization of on-chip system-level applications.

[0020] (3) Compared with the existing point distribution optimization method, the photonic bandgap optimization time of the morphology modification method proposed in the present invention is shorter. When designing disordered ultra-uniform solids suitable for different conditions, the point distribution optimization method needs to generate a new system containing a large number of points and then iteratively optimize the complex system, which is quite time-consuming. The present invention only needs to modify the grid wall of the disordered ultra-uniform solid through different curve functions, without the need to perform a complex iterative optimization process on the system containing a large number of points. It can save time and effectively adjust the performance of the disordered ultra-uniform solid to meet different application requirements.

[0021] (4) Compared with the existing structural coefficient optimization method, the morphology modification method proposed in the present invention has a better photonic band gap optimization effect. The structural coefficient optimization method has a small degree of design freedom, and the ability to optimize the photonic band gap by adjusting the structural coefficient is limited. The present invention can modify the morphology of disordered ultra-uniform solids by selecting curve functions or surface functions with different parameters, thereby regulating the photonic band gap of disordered ultra-uniform solids, providing higher design freedom and flexibility. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the principle of the present invention.

[0023] Figure 2 This is an image of a disordered ultra-uniform solid waveguide device based on morphology modification in specific embodiment 1 of the present invention.

[0024] Figure 3 and Figure 4 These are the simulation results and experimental results of the transmission spectra of the disordered ultra-uniform solid waveguide device before and after modification in the specific embodiment 1 of the present invention.

[0025] Figure 5 This is an image of a disordered ultra-uniform solid cladding microring resonator based on morphology modification in specific embodiment 2 of the present invention.

[0026] Figures 6 to 9 The transmission spectra and fitting curves of the disordered ultra-uniform solid cladding micro-ring resonator modified with different weighted Bezier curves in specific embodiment 2 of the present invention are shown. DETAILED DESCRIPTION

[0027] The present invention will be further described in detail below in conjunction with the accompanying 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.

[0028] Figure 1 The figure shows a method for optimizing disordered ultra-uniform solid devices based on morphology modification protected by the present invention, which adjusts the geometric morphology of disordered ultra-uniform solids through curve functions or surface functions, thereby optimizing the photonic band gap and optical loss characteristics of disordered ultra-uniform solid devices. The optimization method is as follows: first, select several points on the boundary between the hole and the grid wall in the disordered ultra-uniform solid; second, connect and smooth the selected points using curve functions or surface functions; finally, replace the original boundary of the disordered ultra-uniform solid with the smoothed curve or surface to complete the adjustment of its geometric morphology.

[0029] Example 1

[0030] Figure 2 The figure shows a disordered ultra-uniform solid waveguide device, and the enlarged part is a disordered ultra-uniform solid modified by Bezier curve. The waveguide is realized by introducing defect lines in the disordered ultra-uniform solid modified by Bezier curve. The disordered ultra-uniform solid waveguide device is designed and manufactured on a silicon-insulator wafer with a top silicon of 220nm and an oxide buried layer of 3μm. Its specific design parameters are: waveguide width 1000nm, period of disordered ultra-uniform solid 8μm, wall width 200nm, length 10μm.

[0031] The disordered ultra-uniform solid waveguide devices modified by two Bezier curves with weights of ∞ and 1 were simulated and measured respectively. The morphology of the device modified by the Bezier curve with weight ∞ is consistent with that of the unmodified device. Figure 3 and Figure 4 The simulation and measurement results of the transmission spectrum of the unmodified disordered ultra-uniform solid waveguide with weight ∞ are shown in Figure 3 As shown in the figure, the insertion loss of the waveguide at 2280nm wavelength is about -4dB, and the transmission spectrum shows a decrease in transmittance at 2220-2290nm. This may be because the sharp corner of the single chamber designed during the manufacturing process is limited by the processing limit size and is made into a shorter arc line. The simulation and measurement results of the transmission spectrum of the disordered ultra-uniform solid waveguide modified by the Bezier curve with a weight of 1 are shown in Figure 4As shown. The insertion loss of the waveguide at 2280nm is -2.5dB, and it remains flat in the wavelength range of 2200-2300nm. The insertion loss varies by about -2dB near the two edges of the photonic band gap. In addition, the measurement results are more consistent with the simulation, indicating that the tolerance of the manufacturing process for the disordered ultra-uniform solid device modified by Bezier curve is better than that of the unmodified disordered ultra-uniform solid device. Therefore, selecting a Bezier curve with a suitable weight to modify the geometric morphology of the disordered ultra-uniform solid can improve the insertion loss and tolerance to processing errors of the disordered ultra-uniform solid waveguide device.

[0032] Finally, the method of this embodiment is only a preferred implementation scheme and is not intended to limit the protection scope of the present invention. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

[0033] Example 2

[0034] Figure 5 The figure shows a disordered ultra-uniform solid-clad microring resonator modified with a Bezier curve. The microring resonator is realized by covering the disordered ultra-uniform solid outside the microring resonator and etching away the connection between the microring and the disordered ultra-uniform solid. The device is designed and fabricated on a silicon-insulator wafer with a top silicon of 220nm and an oxide buried layer of 3μm. The specific design parameters are: microring radius 2μm, waveguide width 600nm, waveguide and microring spacing 200nm, disordered ultra-uniform solid period 8μm, and wall width 200nm.

[0035] The disordered ultra-uniform solid cladding micro-ring resonator modified by two Bessel curves with weights ∞ and 1 were measured respectively. The device morphology after modification by the Bessel curve with weight ∞ is consistent with the device morphology without modification. The transmission spectrum results are fitted with the Lorentz curve, and the results are as follows Figures 6 to 9 The transmission spectrum of the unmodified disordered ultra-uniform solid cladding micro-ring resonator with weight ∞ is shown in Figure 6 As shown in Figure 2, the resonant wavelength of the microring resonator is 2204.58 nm, the full width at half maximum is 1.40 nm, and the quality factor of the microring resonator is about 1570. The Bezier curves with different weights are used to modify the disordered ultra-uniform solid to change the performance of the disordered ultra-uniform solid cladding microring resonator: The transmission spectrum of the disordered ultra-uniform solid cladding microring resonator modified by the Bezier curve with a weight of 0.5 is shown in Figure 2. Figure 7 As shown in Figure 2, the resonant wavelength of the microring resonator is 2204.58 nm, the full width at half maximum is 1.64 nm, and the quality factor of the microring resonator is about 1340. The transmission spectrum of the disordered ultra-uniform solid cladding microring resonator modified by the Bezier curve with a weight of 1 is shown in Figure 2. Figure 8As shown in Figure 2, the resonant wavelength of the microring resonator is 2206.95 nm, the full width at half maximum is 1.11 nm, and the quality factor of the microring resonator is about 1980. The transmission spectrum of the disordered ultra-uniform solid cladding microring resonator modified by the Bezier curve with a weight of 2 is shown in Figure 2. Fig. 9 As shown, the resonant wavelength of the microring resonator is 2205.57nm, the full width at half maximum is 1.41nm, and the quality factor of the microring resonator is about 1560. Therefore, by selecting a Bezier curve with a suitable weight to modify the geometric morphology of the disordered ultra-uniform solid, the photonic band gap can be optimized and the light field binding ability of the disordered ultra-uniform solid cladding microring resonator can be adjusted.

[0036] 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 solution of the present invention. The above specific embodiments are merely illustrative and not restrictive. Without departing from the scope of the present invention and the scope of protection of the claims, a person of ordinary skill in the art can also make many forms of specific changes under the guidance of the present invention, which all fall within the scope of protection of the present invention.

Claims

1. A method for optimizing disordered ultra-uniform solid devices based on morphology modification, characterized in that: The grid wall of the disordered ultra-uniform solid device is modified by curve functions or surface functions with different weights to regulate and optimize the photonic band gap and optical loss characteristics of the disordered ultra-uniform solid device. The specific steps are as follows: (1) Selecting several points on the boundary between the hole and the grid wall in the disordered ultra-uniform solid device; (2) Connect and smooth the selected points using curve functions or surface functions; (3) The original boundary of the disordered ultra-uniform solid is replaced by a smoothed curve or surface to complete the adjustment of its geometric morphology.

2. The method for optimizing disordered ultra-uniform solid devices based on morphology modification according to claim 1, characterized in that: The grid wall is made of one of silicon, silicon dioxide, germanium, silicon-germanium alloy, silicon nitride, lithium niobate and sulfide.

3. The method for optimizing disordered ultra-uniform solid devices based on morphology modification according to claim 1, characterized in that: The holes are filled with one or more of air, silicon dioxide and silicon nitride.

4. The method for optimizing disordered ultra-uniform solid devices based on morphology modification according to claim 1, characterized in that: The disordered ultra-uniform solid device is a two-dimensional planar structure or a three-dimensional structure.

5. The method for optimizing disordered ultra-uniform solid devices based on morphology modification according to claim 1, characterized in that: The curve function is a combination of one or more of a Bezier curve, an Euler curve, an Euler torus curve, and a quadratic curve; the surface function is a combination of one or more of a Bezier surface, a bi-arc surface, and a quadratic surface.

6. The method for optimizing disordered ultra-uniform solid devices based on morphology modification according to claim 1, characterized in that: The operating wavelength of the disordered ultra-uniform solid device is microwave, THz wave, mid-infrared band or near-infrared band.

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