CN-121657204-B - Optical waveguide and three-channel wavelength division multiplexer

CN121657204BCN 121657204 BCN121657204 BCN 121657204BCN-121657204-B

Abstract

The invention discloses an optical waveguide and a three-channel wavelength division multiplexer, which comprises a waveguide interface, a first energy valley photonic crystal and a second energy Gu Guangzi crystal, wherein the first energy valley photonic crystal is formed by periodically arranging a plurality of first regular hexagonal cells with lattice constants as period lengths, a single first regular hexagonal cell has C 3v rotational symmetry, the upper top point and the lower top point of the first regular hexagonal cell are provided with a first silicon medium column and a second silicon medium column, the second energy Gu Guangzi crystal is formed by periodically arranging a plurality of second regular hexagonal cells with lattice constants as period lengths, the single second regular hexagonal cell has C 3v rotational symmetry, the upper top point and the lower top point of the second regular hexagonal cell are provided with a second silicon medium column and a first silicon medium column, and the edge of the first silicon medium column is longer than that of the second silicon medium column, so that the first regular cell and the second regular cell K point in the same energy band have opposite vortex chirality. The energy valley photonic crystal has C3 symmetry and higher stability.

Inventors

XU XIAOFANG
CHANG YAJING
RAO ZHONGTIAN
LI JIN
Han Zongyue
ZHOU WENJI
DI JIANKE
Wang Qimen
SUN YAN

Assignees

苏州城市学院

Dates

Publication Date: 20260512
Application Date: 20260204

Claims (7)

1. An optical waveguide is characterized by comprising a waveguide interface, and a first energy valley photonic crystal and a second energy Gu Guangzi crystal which are distributed on two sides of the waveguide interface; The single first regular hexagonal unit cell has C 3v rotational symmetry, and is formed by alternately arranging a first silicon medium column and a second silicon medium column at six vertexes of the single first regular hexagonal unit cell, wherein the upper vertexes and the lower vertexes of the first regular hexagonal unit cell are respectively a first silicon medium column and a second silicon medium column; The second energy Gu Guangzi crystal is formed by arranging a plurality of second regular hexagonal unit cells in a honeycomb array with a lattice constant a as a period length, wherein a single second regular hexagonal unit cell has C 3v rotational symmetry, the first silicon medium columns and the second silicon medium columns are alternately arranged at six vertexes of the unit cell, and the upper vertexes and the lower vertexes of the second regular hexagonal unit cell are respectively a second silicon medium column and a first silicon medium column; The cross sections of the first silicon medium column and the second silicon medium column are regular hexagons, and the side length of the first silicon medium column is longer than that of the second silicon medium column, so that the K points of the first regular hexagon unit cell and the second regular hexagon unit cell in the same energy band have opposite vortex chirality; when the waveguide interface is a small Z-shaped boundary, the moving distance of two adjacent second silicon medium columns in the small Z-shaped boundary along the extending direction of the waveguide interface is t=0.33a; When the waveguide interface is a large Z-shaped boundary, the moving distance of two adjacent first silicon medium columns in the large Z-shaped boundary along the extending direction of the waveguide interface is t=0.143 a, or t=0.3125 a, or t=0.5 a.
2. The optical waveguide of claim 1, wherein the optical waveguide is an input waveguide; the small Z-shaped boundary is formed by staggered arrangement of second silicon medium columns of the first regular hexagon unit cells and second silicon medium columns of the second regular hexagon unit cells at intervals.
3. The optical waveguide of claim 1, wherein the optical waveguide is an output waveguide; The large Z-shaped boundary is formed by arranging first silicon medium columns of the first regular hexagon unit cells and first silicon medium columns of the second regular hexagon unit cells in a staggered mode at intervals.
4. An optical waveguide according to claim 1, wherein the lattice constant a=575 nm.
5. The three-channel wavelength division multiplexer is characterized by comprising an excitation source, an input waveguide connected with the excitation source, and a first output waveguide, a second output waveguide and a third output waveguide which are respectively connected with the input waveguide, wherein the working frequency range of the first output waveguide is concentrated at 183-191 THz, the working frequency range of the second output waveguide is concentrated at 194-200 THz, and the working frequency range of the third output waveguide is concentrated at 203-212 THz; the input waveguide, the first output waveguide, the second output waveguide and the third output waveguide all comprise waveguide interfaces, and a first energy valley photonic crystal and a second energy Gu Guangzi crystal which are distributed on two sides of the waveguide interfaces; The single first regular hexagonal unit cell has C 3v rotational symmetry, and is formed by alternately arranging a first silicon medium column and a second silicon medium column at six vertexes of the single first regular hexagonal unit cell, wherein the upper vertexes and the lower vertexes of the first regular hexagonal unit cell are respectively a first silicon medium column and a second silicon medium column; the second energy Gu Guangzi crystal is formed by arranging a plurality of second regular hexagonal unit cells in a honeycomb array with a lattice constant a as a period length, wherein a single second regular hexagonal unit cell has C 3v rotational symmetry, first silicon medium columns and second silicon medium columns are alternately arranged at six vertexes of the unit cell, and the upper vertexes and the lower vertexes of the second regular hexagonal unit cell are respectively a second silicon medium column and a first silicon medium column; The cross sections of the first silicon medium column and the second silicon medium column are regular hexagons, and the side length of the first silicon medium column is longer than that of the second silicon medium column, so that the K points of the first regular hexagon unit cell and the second regular hexagon unit cell in the same energy band have opposite vortex chirality; The waveguide interface of the input waveguide is a small Z-shaped boundary, and the small Z-shaped boundary is formed by arranging second silicon medium columns of the first regular hexagon unit cells and second silicon medium columns of the second regular hexagon unit cells in a staggered manner at intervals; the waveguide interfaces of the three output waveguides are large Z-shaped boundaries, the large Z-shaped boundaries are formed by staggered arrangement of first silicon medium columns of the first regular hexagon unit cells and first silicon medium columns of the second regular hexagon unit cells at intervals, and the moving distances between two adjacent second silicon medium columns in the three waveguide interfaces are different; The moving distance of two adjacent second silicon medium columns in the waveguide interface of the input waveguide along the extending direction of the waveguide interface is t=0.33a, the moving distance of two adjacent first silicon medium columns in the waveguide interface of the first output waveguide along the extending direction of the waveguide interface is t=0.143 a, the moving distance of two adjacent first silicon medium columns in the waveguide interface of the second output waveguide along the extending direction of the waveguide interface is t=0.3125 a, and the moving distance of two adjacent first silicon medium columns in the waveguide interface of the third output waveguide along the extending direction of the waveguide interface is t=0.5a.
6. The three-channel wavelength division multiplexer of claim 5 wherein the input waveguide is a linear waveguide and the first, second and third output waveguides are linear or Z-shaped waveguides.
7. The three-channel wavelength division multiplexer of claim 5 wherein the lattice constant a=575 nm.

Description

Optical waveguide and three-channel wavelength division multiplexer Technical Field The invention belongs to the technical field of photonic crystals, and particularly relates to an optical waveguide and a three-channel wavelength division multiplexer. Background In recent years, photonic integrated circuits (Photonic Integrated Circuits, PICs) have made remarkable progress in the field of modern information processing. As a key platform for all-optical communication and quantum computing, developments have driven the development of a variety of integrated functional devices, such as light sources, optical modulators, transceivers, wavelength division multiplexing (WAVELENGTH DIVISION MULTIPLEXING, WDM) devices, photodetectors, and the like. The Wavelength Division Multiplexing (WDM) device can transmit multiple wavelength optical signals in parallel, and plays an important role in the fields of long-distance communication, data center interconnection, high-performance calculation, and the like. However, the conventional wavelength division multiplexing device based on the dielectric film or the fiber bragg grating has the problems of large volume, high transmission loss, low integration level and the like. To overcome these problems, photonic crystals (Photonic Crystals, PCs) are ideal candidates for realizing high performance wavelength division multiplexing devices due to their unique photonic bandgap tuning capability and flexible structural design. On the basis, the two-dimensional energy Gu Guangzi crystal (Valley Photonic Crystals, VPCs) can simulate the Gu Huoer effect of quantum energy due to the introduction of the energy valley topological state, further enhances the unidirectionality and the robustness of light transmission, and provides a new idea for realizing high-precision wavelength selective separation. The design of the traditional wavelength division multiplexing device is mainly based on a silicon waveguide and an optical fiber, but the performance of the traditional wavelength division multiplexing device is limited by material characteristics and manufacturing processes, and the traditional wavelength division multiplexing device is large in size and is unfavorable for photon integration. Compared with the method, the two-dimensional energy Gu Guangzi crystal is a photonic crystal which realizes high forward transmittance based on a spin valley locking effect, and the high-efficiency regulation and control of light waves are realized through energy Gu Tai (VALLEY STATES) of topology protection. Compared with the traditional photonic crystal, the Gu Guangzi-capable crystal wavelength division multiplexer has remarkable advantages in the aspects of anti-interference capability and transmission efficiency, and generally has a larger working bandwidth. For example, ruan et al propose a three-channel WDM based on a two-dimensional photonic crystal rotating cylindrical array, in which three channels can achieve 9.41 GHz,10.27 GHz, 10.79, GHz frequency transmissions, respectively, but the three channels have low optical transmission efficiency (< 65%) in experimental verification. Xu et al report an original silicon cell generated based on a reverse topology optimization method, so that topology boundary state WDM with high transmission efficiency is successfully constructed, but energy transmission of two channels belonging to 6.3GHz and 12.4GHz can be realized. Wang et al propose a dual channel WDM based on silicon plate air column with dual channels operating in the demultiplexed mode in the communication bands 1500 nm and 1630 nm respectively, but with energy transfer efficiency at both boundary states below 80%. Guo et al precisely regulate and control the lattice constant and the size characteristic of VPCs on the basis of the team design topology power divider, thereby realizing the dual-channel wavelength division multiplexing decomposition function (5.9 GHz, 6.2 GHz) and being capable of being only divided into two channels. Xu et al constructed three-channel multi-angle WDM (10.08 GHz, 9.97 GHz, 9.92 GHz) using A "A-B-A" arrangement with metallic tripodal photonic crystals that introduce rotational degrees of freedom, had the advantages of low cross talk, low scattering, etc., but could not achieve complete demultiplexing of the three frequencies. In summary, for Gu Guangzi crystal WDM, the above research has designed various device architectures based on different cell construction modes, but WDM research with three characteristics of complete multiplexing/demultiplexing, high transmission efficiency and adjustable transmission bandwidth has been recently involved. Disclosure of Invention In view of the above problems, the present invention provides an optical waveguide and a three-channel wavelength division multiplexer, in which the energy valley photonic crystal in the optical waveguide has C3 symmetry, so that the optical waveguide has higher stability. In order to achieve the