Three-dimensional photonic crystal waveguide structure

Abstract

The invention discloses a three-dimensional photonic crystal waveguide structure, and the structure comprises a photonic crystal main body which is provided with a complete photonic band gap; the channel is arranged in the middle of the photonic crystal body in a penetrating mode, and the central axis of the channel coincides with the central axis of the photonic crystal body so that light waves with the wavelength corresponding to the complete photonic band gap can be received and guided. According to the three-dimensional photonic crystal main body structure, the three-dimensional photonic crystal main body structure has a complete photonic band gap. The band gap can effectively limit propagation of electromagnetic waves of a specific wave band in a three-dimensional space.

Description

Technical Field

[0001] The present invention relates to the field of waveguide technology, and in particular to a three-dimensional photonic crystal waveguide structure. Background Art

[0002] A photonic crystal is a material structure consisting of a periodic arrangement of dielectric materials in space, typically composed of two or more materials with different dielectric constants. A two-dimensional photonic crystal waveguide is formed by periodically arranging high- and low-refractive-index materials in a two-dimensional plane. This structure creates a photonic bandgap, where photons of certain frequencies cannot propagate through the crystal. By introducing line defects, waveguides can be formed, allowing light waves at specific frequencies to be precisely guided through the crystal structure, enabling applications such as photonic crystal circulators.

[0003] However, the periodic structure of existing two-dimensional photonic crystal waveguides limits the number and types of waveguide modes that can be supported, restricting their use in applications with multi-mode or special mode requirements. At the same time, they can only restrict the propagation of light within the plane, but cannot effectively restrict it in other polarization directions, resulting in their insufficient performance in high-density optical integration and complex three-dimensional optical applications. Summary of the Invention

[0004] The main purpose of the present invention is to propose a three-dimensional photonic crystal waveguide structure, which aims to solve the problem that it is difficult for users to change the number of electronic photo frames used to display pictures at any time.

[0005] To achieve the above objectives, the present invention proposes a three-dimensional photonic crystal waveguide structure, which includes:

[0006] a photonic crystal body having a complete photonic band gap;

[0007] A channel is provided through the middle of the photonic crystal body, wherein the central axis of the channel coincides with the central axis of the photonic crystal body, so as to receive and guide light waves having a wavelength corresponding to the complete photonic bandgap.

[0008] In some embodiments, the photonic crystal body includes a first photonic crystal array uniformly distributed around the central axis of the channel, and a second photonic crystal array spaced between two adjacent first photonic crystal arrays.

[0009] In some embodiments, the first photonic crystal array and the second photonic crystal array are composed of a plurality of dielectric spheres arranged in an array.

[0010] In some embodiments, the first photonic crystal array is a cubic columnar structure.

[0011] In some embodiments, the second photonic crystal array is a hexagonal columnar structure.

[0012] In some embodiments, the radius of the dielectric sphere is r, satisfying 174 μm≤r≤175 μm.

[0013] In some embodiments, the cross-section of the channel is a regular hexagon.

[0014] In some embodiments, a container for accommodating the photonic crystal body is further included, and a filling ratio of the photonic crystal body to the container is N, satisfying 0.4780≤N≤0.4808.

[0015] In some embodiments, the frequency of the complete photonic bandgap is F, satisfying 215 GHz ≤ F ≤ 225 GHz.

[0016] The technical solution of the present invention constructs a three-dimensional photonic crystal main structure so that it has a complete photonic bandgap. This bandgap can effectively limit the propagation of electromagnetic waves of a specific wavelength band in three-dimensional space. Compared with two-dimensional photonic crystals, this three-dimensional structure has omnidirectional photonic bandgap characteristics. When the wavelength of the electromagnetic wave is within the bandgap range, no matter from which angle the electromagnetic wave is incident, it cannot propagate in the photonic crystal main body and can only be restricted to the specific channel formed in the middle of the structure. Therefore, the photonic crystal main body is insensitive to the angle of the incident light and can support multiple modes and numbers of waveguides. At the same time, thanks to the photonic bandgap effect, external stray electromagnetic waves with the same wavelength frequency as the electromagnetic wave cannot enter the interior of the structure, thereby effectively isolating external interference, ensuring the intensity and stability of electromagnetic wave transmission, and significantly enhancing the ability to constrain electromagnetic waves. These characteristics provide important technical support for the realization of cutting-edge applications such as high speed and low latency in future 6G millimeter wave communications. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a three-dimensional schematic diagram of a three-dimensional photonic crystal waveguide structure according to an embodiment of the present application;

[0018] Figure 2 for Figure 1 A top view of a stereogram;

[0019] Figure 3 This is a three-dimensional schematic diagram of a first photonic crystal array in a three-dimensional photonic crystal waveguide structure according to an embodiment of the present application;

[0020] Figure 4 This is a three-dimensional schematic diagram of a second photonic crystal array in a three-dimensional photonic crystal waveguide structure according to an embodiment of the present application;

[0021] Figure 5This is a three-dimensional schematic diagram of a channel formed by a first photonic crystal array in a three-dimensional photonic crystal waveguide structure according to an embodiment of the present application;

[0022] Figure 6 for Figure 5 A top view of a stereogram;

[0023] Figure 7 A complete photonic bandgap distribution diagram of a three-dimensional photonic crystal waveguide structure according to an embodiment of the present application;

[0024] Figure 8 Schematic diagram of the transmission rate of a channel in a three-dimensional photonic crystal waveguide structure according to an embodiment of the present application. DETAILED DESCRIPTION

[0025] The following will be combined with the accompanying drawings to clearly and completely describe the solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0026] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the various components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0027] It should also be noted that when an element is referred to as being "fixed on" or "disposed on" another element, it may be directly on the other element or there may be an intermediate element. When an element is referred to as being "connected to" another element, it may be directly connected to the other element or there may be an intermediate element.

[0028] In addition, the descriptions of "first", "second", etc. in the present invention are for descriptive purposes only and should not be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between the various embodiments can be combined with each other, but this must be based on the fact that they can be implemented by ordinary technicians in this field. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0029] In this embodiment, a three-dimensional photonic crystal structure is proposed, referring to Figure 1 and Figure 2, the structure comprises: a photonic crystal body 10, wherein the photonic crystal body 10 has a complete photonic band gap;

[0030] The channel 20 is provided through the middle of the photonic crystal body 10 , and the central axis of the channel 20 coincides with the central axis of the photonic crystal body 10 , so as to receive and guide light waves having a wavelength corresponding to the complete photonic bandgap.

[0031] In this embodiment, a three-dimensional photonic crystal waveguide structure is disclosed, primarily for achieving precise transmission and control of light waves of specific wavelengths at the micrometer scale. The photonic crystal body 10 is constructed using a periodic dielectric structure with a regular refractive index distribution in three dimensions, thereby forming a photonic band gap. The photonic crystal body 10 can be a three-dimensional face-centered structure, a three-dimensional body-centered structure, a diamond-type structure, or other structures. Two materials with high dielectric constant contrast are selected, exemplarily, air with a dielectric constant of 1 and a dielectric constant relative to air of 23.04, to form a significant refractive index periodicity.

[0032] In this embodiment, the channel 20 is an air channel 20 that runs through the photonic crystal body 10. Its cross-section can be a regular polygon or a circle, and its axis coincides with the geometric center axis of the photonic crystal body 10. The channel 20 provides a propagation path for light waves. Exemplarily, the channel 20 is circular, and the radius is set to 0.8 times the lattice constant, which allows light waves of a specific wavelength to propagate along the channel 20 without generating light reflection loss. The channel 20 is formed by selectively removing part of the high dielectric constant dielectric material when constructing the photonic crystal body 10, and runs through the entire crystal structure along the Z-axis. Since the channel 20 is located inside a crystal with a complete photonic band gap, light waves at the edge of the band gap cannot pass through the crystal structure and can only propagate along the channel 20, thereby forming a good waveguide effect. The photonic crystal body 10 can be prepared by methods such as dip pen nanolithography, colloidal microsphere self-assembly, electron beam direct writing, and reactive ion beam etching.

[0033] This embodiment achieves strong confinement and low-loss transmission of light waves of a specific wavelength by introducing a Z-axis channel 20 into the structure of a three-dimensional photonic crystal body 10 with a complete photonic band gap, effectively suppressing lateral leakage and backscattering, and is particularly suitable for use in optical communications, integrated optical circuits, quantum information and other fields.

[0034] Reference Figure 3 and Figure 4 In one embodiment, the photonic crystal body 10 includes a first photonic crystal array 11 uniformly distributed around the central axis of the channel 20 , and a second photonic crystal array 12 spaced between two adjacent first photonic crystal arrays 11 .

[0035] In this embodiment, the first photonic crystal array 11 can be in a ring or annular shape, uniformly distributed in the radial direction of the central axis of the channel 20, and is the main part of forming a complete photonic band gap. The first photonic crystal array 11 is a periodically arranged structure constructed using a high dielectric constant material (such as silicon). The crystal structure can be a simple body-centered cubic, face-centered cubic, or diamond structure. Its function is to provide effective confinement of propagating light and prevent light waves from leaking to the outside. Exemplarily, the first photonic crystal array 11 is a simple body-centered cubic structure.

[0036] The second photonic crystal array 12 is disposed between adjacent first photonic crystal arrays 11. It is a periodically arranged structure constructed using the same dielectric constant material as the first photonic crystal array 11, but has a different crystal structure from the first photonic crystal array 11, and is used to fill the gaps between the second photonic crystal arrays 12. The arrangement of the first photonic crystal array 11 and the second photonic crystal array 12 with different crystal structures is primarily intended to facilitate the construction of the photonic crystal body 10. The first photonic crystal array 11 can be rotated around the axis of a side channel 20 to form the main portion, with the second photonic crystal array 12 filling the gaps between the main portion. The combined design of the first and second photonic crystal arrays 12 provides the photonic crystal body 10 with greater structural flexibility.

[0037] Reference Figure 3 and Figure 4 As shown, in one embodiment, the first photonic crystal array 11 and the second photonic crystal array 12 are composed of a plurality of dielectric spheres arranged in an array.

[0038] In this embodiment, the first photonic crystal array 11 and the second photonic crystal array 12 are both composed of a plurality of dielectric spheres arranged in an array. The dielectric spheres have a high refractive index, such as silicon, gallium arsenide, etc. The three-dimensional arrangement of the dielectric spheres can be a simple body-centered cubic structure or a face-centered cubic structure to ensure that the structure forms a complete three-dimensional photonic band gap. The dielectric spheres are simply stacked repeatedly in a non-dense manner, stacked layer by layer, and evenly distributed around the channel 20 to form a high refractive index structure around the central axis of the channel 20. The use of dielectric spheres to construct the first and second photonic crystal arrays has good manufacturing adaptability and can be achieved through methods such as colloidal self-assembly, nano-printing or multi-photon polymerization. The periodic structure formed by the multi-layer dielectric sphere array can effectively generate a three-dimensional complete photonic band gap.

[0039] Reference Figure 3 and Figure 4 As shown, in one embodiment, the first photonic crystal array 11 is a cubic columnar structure; the second photonic crystal array 12 is a hexagonal columnar structure.

[0040] In this embodiment, the first photonic crystal array 11 is a cubic prism structure, specifically a simple cubic structure. Each layer is provided with a three-by-four rectangular dielectric sphere, totaling twelve dielectric spheres, with six layers provided. Six dielectric spheres are evenly arranged by rotating the first photonic crystal array 11 around a vertical central axis on one side, forming a central channel 20. The second photonic crystal array 12 is a hexagonal prism structure, or a triangular prism structure formed by a simple arrangement of dielectric spheres. In this case, each layer is provided with three dielectric spheres in the shape of an equilateral triangle, with six layers provided. The structure is embedded in the gap between two adjacent first photonic crystal arrays 11. Because the first photonic crystal array 11 surrounds and forms the channel 20, the second photonic crystal array 12 is also periodically arranged around the channel 20, achieving optimized space filling.

[0041] In one embodiment, the radius of the dielectric sphere is r, which satisfies 174 μm≤r≤175 μm.

[0042] In this embodiment, the radius of the dielectric spheres is controlled between 174 μm and 175 μm, preferably 174.5 μm. Combined with the minimum contact gap between the spheres, the lattice constant is determined to be 364, making it suitable for constructing millimeter-wave / terahertz photonic bandgap structures for frequencies between 215 GHz and 225 GHz. The dielectric spheres are large enough to support the construction of fine three-dimensional periodic arrays and are easily fabricated using processes such as laser direct writing, template-based microsphere deposition, and self-assembled microsphere lithography.

[0043] In one embodiment, the cross section of the channel 20 is a regular hexagon.

[0044] In this embodiment, the channel 20 is formed by enclosing six first photonic crystal arrays 11. The first photonic crystal array 11 is a simple cubic structure, consisting of four dielectric spheres in the length direction and three dielectric spheres in the width direction. When enclosing the channel 20, the dielectric spheres close to the side of the channel 20 form a regular hexagonal cross-section. The two adjacent sides of the regular hexagon share a dielectric sphere as the vertex of the corner. In this way, each side is composed of three dielectric spheres, and the number of dielectric spheres forming the regular hexagonal channel 20 is twelve. In the above structure, the two opposite sides of the channel 20 jointly form a polarization transmission mode. In this case, the regular hexagon has three polarization transmission modes. Of course, the two adjacent sides of the regular hexagon can form the vertex of a corner through two dielectric spheres. In this case, the number of dielectric spheres forming the regular hexagonal channel 20 is eighteen.

[0045] Reference Figure 1 and Figure 2 In one embodiment, it further includes a container for accommodating the photonic crystal body 10, and the filling ratio of the photonic crystal body 10 to the container is N, satisfying 0.4780≤N≤0.4808.

[0046] In this embodiment, the three-dimensional photonic crystal waveguide structure also includes a container for fixing and supporting the photonic crystal body 10 structure to achieve its stable packaging, optical isolation and device integration. The container can be a cube, a cylinder or a regular hexagonal prism structure, and its inner cavity size is slightly larger than the outer boundary of the photonic crystal body 10; the photonic crystal body 10 is arranged inside the container by injection or other methods. The filling ratio is defined as the volume ratio of the photonic crystal body 10 in the container. Preferably, the filling ratio is 0.4794. At this time, the radius of the dielectric sphere constituting the photonic crystal body 10 is 174.5μm, the lattice constant is 364μm, and the relative dielectric constant is 23.04. The setting of the above filling ratio determines the frequency range of the complete photonic band gap.

[0047] In one embodiment, the frequency of the full photonic bandgap is F, which satisfies 215 GHz≤F≤225 GHz.

[0048] In this embodiment, in order to realize a complete photonic bandgap within this frequency range, the process of setting up the photonic crystal body 10 is as follows: First, the subunits constituting the photonic crystal body 10 are set, specifically, as follows: Figure 3 and Figure 4 As shown, a first photonic crystal array 11 with a simple cubic structure and a second photonic crystal array 12 with a hexagonal columnar structure are provided. By rotating the first photonic crystal array 11, a structure as shown in FIG. Figure 5 and Figure 6 The three-dimensional structure shown in FIG. 1 is then filled with the second photonic crystal array 12 to form a Figure 1 and Figure 2 The three-dimensional structure shown. The photonic crystal body 10 is obtained by scanning the combination of the second photonic crystal array 12 and the first photonic crystal array 11 through MOST in Rsoft, and a complete photonic band gap is obtained. The scanning steps include: preparing the designed photonic crystal body 10 model, adding the lattice constant a as a variable, ranging from 0.5μm to 1.0μm, with a step size of 0.05μm, adding the dielectric sphere radius r as a variable, ranging from 0.1a to 0.4a, with a step size of 0.02a; adding the band gap width as the objective function, adding the normalized frequency as the auxiliary objective function, running about 200 simulations through MOST, using a line graph to view the change of the band gap width with r / a under different a values, using a contour map to view the band gap width distribution in the ar two-dimensional parameter space, and finding the parameter combination with the largest band gap width, such as Figure 7As shown, a fine scan is performed, and finally the various parameters under this three-dimensional structure design are obtained, specifically: the lattice constant is 364μm, the radius of the dielectric sphere is 174.5μm, the side length of the regular hexagon of the waveguide channel 20 is 743μm, the relative dielectric constant is 23.04, and the filling ratio is 0.4794. The range of the complete photonic band gap of the waveguide channel 20 is 215GHz≤F≤225GHz. That is, the frequency range of the electromagnetic wave that can be transmitted. Finite element analysis is performed through COMSOL to analyze its transmission efficiency, including: determining the analysis mode, importing the photonic crystal body 10 model, setting the material refractive index and other parameters of the photonic crystal body 10, setting the boundary conditions (including ports and photonic crystal boundaries), dividing the waveguide area grid, and performing calculations. The following is obtained Figure 8 The results shown.

[0049] In this embodiment, a three-dimensional photonic crystal body 10 is constructed to possess a complete photonic bandgap. This bandgap effectively restricts the propagation of electromagnetic waves of a specific wavelength band within three-dimensional space. Compared to two-dimensional photonic crystals, this three-dimensional structure exhibits omnidirectional photonic bandgap properties. When the wavelength of an electromagnetic wave falls within this bandgap range, regardless of the angle of incidence, the electromagnetic wave cannot propagate within the photonic crystal body 10 and is confined to a specific channel 20 formed in the center of the structure. Therefore, the photonic crystal body 10 is insensitive to the angle of incident light and can support a variety of modes and numbers of waveguides. Furthermore, thanks to the photonic bandgap effect, external stray electromagnetic waves with the same wavelength frequency as the electromagnetic wave cannot enter the structure, effectively isolating it from external interference, ensuring the strength and stability of electromagnetic wave transmission, and significantly enhancing its ability to confine electromagnetic waves. Advantages include a simple structure, multiple transmitted polarization states, enhanced electromagnetic wave confinement, a complete photonic bandgap, and the ability to simultaneously transmit TE and TM waves.

[0050] The above description is only a partial or preferred embodiment of the present invention. Neither the text nor the drawings can limit the scope of protection of the present invention. Any equivalent structural transformation made by using the contents of the present invention specification and drawings under the overall concept of the present invention, or direct / indirect application in other related technical fields, is included in the scope of protection of the present invention.

Claims

1. A three-dimensional photonic crystal waveguide structure, characterized in that: include: a photonic crystal body having a complete photonic band gap; A channel is provided through the middle of the photonic crystal body, wherein the central axis of the channel coincides with the central axis of the photonic crystal body, so as to receive and guide light waves having a wavelength corresponding to the complete photonic bandgap.

2. The three-dimensional photonic crystal waveguide structure according to claim 1, characterized in that: The photonic crystal body includes a first photonic crystal array uniformly distributed around the central axis of the channel, and a second photonic crystal array spaced between two adjacent first photonic crystal arrays.

3. The three-dimensional photonic crystal waveguide structure according to claim 2, wherein: The first photonic crystal array and the second photonic crystal array are composed of a plurality of dielectric spheres arranged in an array.

4. The three-dimensional photonic crystal waveguide structure according to claim 3, wherein: The first photonic crystal array is a cubic columnar structure.

5. The three-dimensional photonic crystal waveguide structure according to claim 3, wherein: The second photonic crystal array is a hexagonal columnar structure.

6. The three-dimensional photonic crystal waveguide structure according to claim 3, characterized in that: The radius of the dielectric sphere is r, which satisfies 174 μm≤r≤175 μm.

7. The three-dimensional photonic crystal waveguide structure according to claim 1, characterized in that: The cross section of the channel is a regular hexagon.

8. The three-dimensional photonic crystal waveguide structure according to claim 1, wherein: It also includes a container for accommodating the photonic crystal body, and the filling ratio of the photonic crystal body to the container is N, satisfying 0.4780≤N≤0.4808.

9. The three-dimensional photonic crystal waveguide structure according to claim 1, wherein: The frequency of the complete photonic bandgap is F, which satisfies 215 GHz≤F≤225 GHz.

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