A photonic crystal router applied to a mesh on-chip optical network

Abstract

This invention discloses a photonic crystal router for use in Mesh on-chip optical networks. The router consists of two 2×4 routing basic units and two 2×2 routing basic units, each containing only a cross-waveguide structure. The 2×4 routing basic unit comprises three cross-waveguide structures including horizontal input and output waveguides; the 2×2 routing basic unit is a cross-waveguide structure including vertical input and output waveguides. The entire router structure is vertically and horizontally symmetrical. A phase-change material is selected as the dielectric pillar material. By flexibly adjusting the refractive index of the key dielectric pillar at the center of the cross-waveguide structure, this structure can be applied to Mesh on-chip optical networks to achieve end-to-end non-blocking routing and wavelength-selective routing functions. Compared with existing 4×4 photonic crystal routers, this invention's router offers richer routing functions and features a simple structure, high transmission efficiency, and ease of implementation, making it important for applications in all-optical communication and on-chip networks.

Description

Technical Field

[0001] This invention relates to a photonic crystal router, which can be applied to Mesh on-chip optical networks in optical communication systems to realize data routing and information exchange between nodes, and is applicable to optical communication, especially the field of optical network technology. Background Technology

[0002] In recent years, the development of photonic integration technology has made it possible to apply optical interconnect technology to on-chip optical networks. As the core of an optical network, the optical router is responsible for routing and data exchange between nodes; therefore, the performance of the optical router directly determines the communication quality of the optical network. Photonic crystals, as a novel type of artificial microstructure, possess two unique characteristics: photonic bandgap and photonic localization, giving them excellent control over light. Optical routers designed based on photonic crystals feature low power consumption, low latency, and small size.

[0003] Currently, most photonic crystal routers are composed of basic units with ring resonant cavity structures, mainly including 1×2, 1×3, and 2×2 basic units. Higher-order N×N photonic crystal routers are constructed by combining multiple basic units. How to design the basic units and how to effectively combine them is crucial to the design of photonic crystal routers, directly affecting their functionality and characteristics.

[0004] Prior art [1] (IEEE Photonics Journal, Calo G, Petruzzi V. 2013, 5(3): 7901011.) discloses a 4×4 photonic crystal router based on a 1×2 basic unit. The 1×2 basic unit consists of a photonic crystal cross-shaped waveguide and a photonic crystal ring resonator located at the corner of the cross-shaped waveguide. By combining eight of these 1×2 basic units, wavelength selection functions of three wavelengths, 1488nm, 1506nm, and 1540nm, are realized. This router requires eight ring resonators and eight cross-shaped waveguides, has a complex structure, and only has a single wavelength selection routing function.

[0005] Prior art [2] (see Journal of the Optical Society of America B,G Calò,Petruzzelli V.2014,31(3):517-525.) discloses a 4×4 photonic crystal router based on 2×2 basic units. The 2×2 basic unit consists of a photonic crystal cross-shaped waveguide and two photonic crystal ring resonators located at the corner of the cross-shaped waveguide. The router is composed of four 2×2 basic units, which are symmetrical on all four sides and realize the wavelength selection function of three wavelengths: 1500nm, 1507nm, and 1513nm. The router structure contains eight ring resonators and four cross-shaped waveguides. The structure is still relatively complex and still only has a single wavelength selection routing function, which cannot simultaneously realize the non-blocking routing function.

[0006] Prior art [3] (see Optical and Quantum Electronics, Sathyadevaki R, Sridarshini T, Sivanantha Raja A. 2018, 50(11): 1-15.) discloses a 4×4 non-blocking photonic crystal router constructed based on 1×2 and 2×2 basic units. The router is composed of four 1×2 basic units and two 2×2 basic units. The router contains eight ring resonators and ten cross waveguides, and has a complex structure.

[0007] Prior art [4] (see Optik, Zhang J, Zhao M, Wang Y. 2022, 254: 168693.) discloses a 4×4 photonic crystal router based on a 1×3 basic unit. The 1×3 basic unit consists of a single nested double-ring resonant cavity, intersecting straight waveguides, and 90° bent waveguides. By combining four of these 1×3 basic units, non-blocking and wavelength-selective routing functions can be realized simultaneously. However, this router only has eight non-blocking routing transmission states, and the routing function is incomplete.

[0008] Prior art [5] (see Zhang Juan, Zhao Mingwei. A photonic crystal optical router with a cross-waveguide structure, CN114815052A.2022.4.21.) discloses a specially designed X-shaped cross-waveguide structure. By adjusting the refractive index of the four central dielectric pillars at the cross-section to control the light flow direction, the functions of cross-transmission, direct transmission and beam splitting of light can be flexibly realized. This photonic crystal router only realizes simple multi-functional optical routing transmission and cannot be directly applied to on-chip optical networks to realize information interaction between multiple processor cores.

[0009] Currently, most photonic crystal routers used in on-chip optical networks consist of ring resonant cavities and cross waveguides as basic units. Therefore, when multiple basic units are combined to implement higher-order routers, the structure becomes quite complex. Furthermore, most routers only have wavelength selection functionality, which is limited. Achieving non-blocking functionality makes the router structure even more complex and difficult to implement, thus restricting the application of photonic crystal routers. Summary of the Invention

[0010] In order to solve the problems of the prior art, the purpose of this invention is to overcome the shortcomings of the existing technology and provide a photonic crystal non-blocking wavelength selection router that is simple in structure, powerful in function, high in transmission efficiency, excellent in performance and easy to implement.

[0011] To achieve the above objectives, the concept of this invention is as follows:

[0012] Leveraging the flexibility of X-shaped cross-waveguides in both direct and cross-transmission, the basic routing unit is constructed using only cross-waveguides. The router structure includes two types of basic routing units: a 2×4 unit and a 2×2 unit. Two 2×4 units are placed symmetrically side-by-side (or top-bottom), and two more 2×2 units are placed symmetrically top-bottom (or side-by-side). The entire router structure is formed by interconnecting their two output ports with specific output ports of the 2×4 units. By adjusting the refractive index of the key dielectric pillar at the center of the cross-waveguide, wavelength selectivity and non-blocking routing capabilities can be flexibly achieved.

[0013] Based on the above inventive concept, the present invention adopts the following technical solution:

[0014] A photonic crystal router for use in Mesh on-chip optical networks employs a two-dimensional photonic crystal of square lattice dielectric pillar type, consisting of two 2×4 basic units (M1, M2) placed symmetrically on the left and right, and two 2×2 basic units (D1, D2) placed symmetrically on the top and bottom; all basic units are constructed from X-shaped cross waveguide structures.

[0015] Preferably, each of the two 2×4 basic units (M1, M2) contains three X-shaped cross waveguide structures:

[0016] One of the 2×4 basic units (M1) has the first X-shaped cross waveguide structure (M1.1) on the left, and the second and third X-shaped cross waveguide structures (M1.2 and M1.3) on the right, and are placed symmetrically vertically. The other two 2×4 basic units (M1 and M2) are symmetrical horizontally. The other 2×4 basic unit (M2) has the first X-shaped cross waveguide structure (M2.1) on the right, and the second and third X-shaped cross waveguide structures (M2.2 and M2.3) on the left, and are placed symmetrically vertically.

[0017] Preferably, each of the X-shaped cross waveguide structures (M1.1, M1.2, M1.3, M2.1, M2.2, and M2.3) is an X-shaped cross waveguide with horizontal waveguides at four ports; wherein the upper right port of M1.1 is connected to the upper left port of M1.2; the lower right port of M1.1 is connected to the lower left port of M1.3; and the lower left port of M1.2 is connected to the upper left port of M1.3, thus forming a 2×4 basic unit M1; while the upper left port of M2.1 is connected to the upper right port of M2.2; the lower left port of M2.1 is connected to the lower right port of M2.3; and the lower right port of M2.2 is connected to the upper right port of M2.3, thus forming a 2×4 basic unit M2.

[0018] Preferably, the two middle ports of the two 2×4 basic units (M1, M2) are interconnected.

[0019] Preferably, the 2×2 basic unit (D1, D2) is an X-shaped cross waveguide with vertical waveguides at four ports.

[0020] Preferably, the two ports of the 2×2 basic unit (D1, D2) are respectively connected to the outer ports of the two 2×4 basic units (M1, M2) on the left and right.

[0021] Preferably, the X-shaped cross waveguide is composed of two waveguides orthogonal to the horizontal direction at 45°, and the width of the cross waveguide is... The spacing between adjacent dielectric pillars at the edge of the cross waveguide is a is the lattice constant of the background dielectric column.

[0022] Preferably, in the entire router structure, except for the dielectric pillars 2 and 4, whose radii differ from the background dielectric pillars, the radii of the other dielectric pillars are the same as the background dielectric pillars; and the refractive indices of the key dielectric pillars at each X-shaped cross waveguide center are different.

[0023] Preferably, the entire structure is symmetrical vertically and horizontally, with a total of eight ports in four directions. Two ports in each direction can be used as input ports or output ports. When one port is an input port, the other port is an output port.

[0024] Preferably, by selecting the appropriate refractive index of the key dielectric pillar at the center of each cross waveguide structure, wavelength selection routing function for input light of different wavelengths can be achieved.

[0025] Preferably, by selecting the appropriate refractive index of the key dielectric pillar at the center of each cross waveguide structure, the full-link non-blocking optical routing function in nine states can be achieved.

[0026] Compared with the prior art, the present invention has the following obvious and prominent substantive features and significant advantages:

[0027] In terms of structure, the structure of this invention only uses cross waveguides to construct a 4×4 photonic crystal router. There is no ring resonator in the entire structure. Compared with the basic unit with ring resonator used in prior art [1]-[4], the basic unit structure of this invention is simpler and easier to actually fabricate. In terms of routing function, compared with prior art [1] and prior art [2] which only realize wavelength selection function, and prior art [3] which realizes non-blocking routing function, the structure of this invention can not only realize wavelength selection routing function, but also realize non-blocking optical routing function of the whole link, which is more powerful. Although prior art [4] realizes non-blocking and wavelength selection routing function at the same time, it only has eight non-blocking states. The structure of this invention has nine states of non-blocking transmission, which is more complete and more flexible. Compared with prior art [5] which only realizes simple multi-functional optical routing transmission and cannot be directly applied to on-chip optical networks to realize information interaction between multiple processor cores, the structure of this invention can be directly applied to Mesh on-chip optical networks. In summary, the basic structural unit of this invention does not contain a ring resonant cavity, but only has a cross waveguide structure, which has the outstanding characteristics of simple structure, easy implementation, powerful function and high flexibility. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the photonic crystal optical router of the present invention. The entire structure consists of two 2×4 basic units M1 and M2, and two 2×2 basic units D1 and D2. Cross waveguide structures M1.1, M1.2, and M1.3 are interconnected to form the 2×4 basic unit M1, and cross waveguide structures M2.1, M2.2, and M2.3 are interconnected to form the 2×4 basic unit M2.

[0029] Figure 2This is a schematic diagram of the 2×4 basic unit M1. It contains three X-shaped cross waveguide structures M1.1, M1.2, and M1.3. Each X-shaped cross waveguide structure is an X-shaped cross waveguide with horizontal waveguides at four ports. The width of the cross waveguide is... At the edge of the cross waveguide, the spacing between the dielectric pillars is a is the lattice constant of the background dielectric pillar. Dielectric pillars 1, 2, 3, and 4 are the four key dielectric pillars at the center of their cross-waveguides.

[0030] Figure 3 This is a schematic diagram of a 2×2 basic unit structure. It is an X-shaped cross waveguide with vertical waveguides at four ports, and the width of the cross waveguide is... The spacing between dielectric pillars at the edge of the cross waveguide is a is the lattice constant of the background dielectric pillar. Dielectric pillars 1, 2, 3, and 4 are the four key dielectric pillars at the center of their cross-waveguides.

[0031] Figure 4 The light field distribution and transmission spectrum of light of different wavelengths simultaneously input from port N1 of the structure of Embodiment 1 of the present invention and output from different output ports are shown. (a) is the light field distribution of 1410nm light input from port N1 and output from port S2; (b) is the light field distribution of 1520nm light input from port N1 and output from port E2; (c) is the light field distribution of 1550nm light input from port N1 and output from port W2; (d) is the transmission spectrum of ports S2, E2, and W2.

[0032] Figure 5 (a) is the light field distribution diagram of 1550nm light entering from port W1 and exiting from port S2 after passing through three cross waveguides in Embodiment 2 of the present invention; (b) is the transmission spectrum of ports W2, S2, E2 and N2.

[0033] Figure 6 (a) is the light field distribution diagram of 1550nm light entering from port W1 and passing through three cross waveguides to output from port N2 in Embodiment 2 of the present invention; (b) is the transmission spectrum of ports W2, S2, E2 and N2.

[0034] Figure 7 (a) is the light field distribution diagram of 1550nm light entering from port W1 and passing through four cross waveguides to output from port E2 in Embodiment 2 of the present invention; (b) is the transmission spectrum of ports W2, S2, E2 and N2.

[0035] Figure 8 (a) is the light field distribution diagram of 1550nm light entering from port N1 and passing through four cross waveguides to output from port S2 in Embodiment 2 of the present invention; (b) is the transmission spectrum of ports W2, S2, E2 and N2.

[0036] Figure 9 (a) is the light field distribution diagram of 1550nm light entering from port W1 and passing through five cross waveguides to output from port S2 in Embodiment 2 of the present invention; (b) is the transmission spectrum of ports W2, S2, E2 and N2. Detailed Implementation

[0037] The above solution will be further described below with reference to specific embodiments. The preferred embodiments of the present invention are described in detail below:

[0038] Example 1:

[0039] In this embodiment, a photonic crystal router with a cross-waveguide structure is provided. It adopts a two-dimensional photonic crystal of square lattice dielectric pillar type and is composed of two 2×4 basic units M1 and M2 placed symmetrically on the left and right and two 2×2 basic units D1 and D2 placed symmetrically on the top and bottom; all basic units are composed of X-shaped cross-waveguide structures.

[0040] This embodiment provides a photonic crystal non-blocking wavelength selection router that is simple in structure, powerful in function, excellent in performance, and easy to implement.

[0041] Example 2:

[0042] See Figure 1 , Figure 2 and Figure 3 This embodiment is basically the same as Embodiment 1, with the following differences:

[0043] The two 2×4 basic units each contain three X-shaped cross waveguide structures. In one 2×4 basic unit M1, the first X-shaped cross waveguide structure M1.1 is located on the left, and the second and third X-shaped cross waveguide structures M1.2 and M1.3 are located to the right of the first X-shaped cross waveguide structure M1.1, arranged symmetrically vertically. In the other 2×4 basic unit M2, the first X-shaped cross waveguide structure M2.1 is located on the right, and the second and third X-shaped cross waveguide structures M2.2 and M2.3 are located to the left of the first X-shaped cross waveguide structure M2.1, arranged symmetrically vertically. All X-shaped cross waveguide structures M1.1, M1.2, M1.3, M2.1, M2.2, and M2.3 together form an X-shaped cross waveguide with horizontal waveguides at four ports. The upper right port of M1.1 is connected to the upper left port of M1.2; the lower right port of M1.1 is connected to the lower left port of M1.3; and the lower left port of M1.2 is connected to the upper left port of M1.3, thus forming a 2×4 basic unit M1. The upper left port of M2.1 is connected to the upper right port of M2.2; the lower left port of M2.1 is connected to the lower right port of M2.3; and the lower right port of M2.2 is connected to the upper right port of M2.3, thus forming a 2×4 basic unit M2. The middle two ports of the two 2×4 basic units M1 and M2 are interconnected.

[0044] The 2×2 basic units D1 and D2 constitute an X-shaped cross waveguide with vertical waveguides at four ports. The 2×4 and 2×2 basic units have two ports connected to the outer ports of the two 2×4 basic units on either side. The X-shaped cross waveguide is characterized by being composed of two waveguides orthogonal to the horizontal direction at 45°, with a width of [missing information]. The spacing between adjacent dielectric pillars at the edge of the cross waveguide is 'a' represents the lattice constant of the background dielectric pillars. In the aforementioned X-shaped cross-waveguides, the radii of the dielectric pillars at the centers of all X-shaped cross-waveguides in the entire router structure are the same as those of the background dielectric pillars, except for the radii of dielectric pillars 2 and 4. Furthermore, the refractive indices of the key dielectric pillars at the centers of each X-shaped cross-waveguide are different.

[0045] The aforementioned photonic crystal router is symmetrical both vertically and horizontally, with eight ports in four directions. Two ports in each direction can serve as both input and output ports; when one port is an input port, the other is an output port. By selecting appropriate refractive indices for the key dielectric pillars at the center of each cross-waveguide structure, this router structure can achieve wavelength-selective routing for input light of different wavelengths and nine states of full-link non-blocking optical routing.

[0046] This invention employs only cross-waveguides to construct a 4×4 photonic crystal router, with no ring resonator in the entire structure. The basic unit structure of this invention is simpler and easier to fabricate. Regarding routing functionality, this embodiment not only enables wavelength-selective routing but also achieves full-link non-blocking optical routing, offering greater functionality. This embodiment features nine states of non-blocking transmission, providing a more complete and flexible non-blocking transmission capability. This embodiment can be directly applied to Mesh on-chip optical networks. In summary, this embodiment's basic unit structure, lacking a ring resonator and consisting only of a cross-waveguide structure, possesses outstanding characteristics such as simple structure, ease of implementation, powerful functionality, and high flexibility.

[0047] Example 3:

[0048] This embodiment is basically the same as the above embodiments, with the following differences:

[0049] This implementation is used to achieve wavelength selection routing for 1410nm, 1520nm and 1550nm optical signals.

[0050] See Figure 1 , Figure 2 and Figure 3 A photonic crystal router for Mesh on-chip optical networks is described. Its basic structure is a two-dimensional photonic crystal with square lattice dielectric pillars, with 95 horizontal and 59 vertical dielectric pillars. Ports W1, N1, E1, and S1 are input ports, and ports W2, N2, E2, and S2 are output ports. The background is air, and the dielectric pillar material is Ge2Sb2Se4Te1 (GSST), a phase-change material with low absorption characteristics in the optical communication wavelength range. External excitation (such as laser pulse irradiation) is used to achieve rapid transitions between different states of the material, flexibly controlling the refractive index of the dielectric pillars. In both the 2×4 and 2×2 basic units, the cross-waveguide width is... The spacing between dielectric pillars at the edge of the cross waveguide is The lattice constant a = 0.58 μm, and the refractive index and radius of the background dielectric pillars are n = 3.46 and R = 0.08 μm, respectively. The radii of dielectric pillars 2 and 4 at the center of the cross waveguide are 0.115 μm, and the radii of dielectric pillars at other locations are the same as those of the background dielectric pillars.

[0051] Table 1 shows the optical links and the operating status of each cross waveguide structure when 1410nm, 1520nm and 1550nm light are simultaneously input into the four input ports of the router.

[0052] Table 1. Optical link and cross-waveguide operation status when different light sources are simultaneously input to the four input ports of the router.

[0053]

[0054] In Table 1, state P1 corresponds to the cross-transmission of 1410nm and 1520nm wavelength light in the X-shaped cross waveguide, and the straight-through transmission of 1550nm wavelength light. At this time, the refractive indices of the key dielectric pillars 1, 2, 3 and 4 at the center of the cross waveguide are 4.7, 3.4, 3.9 and 3.4, respectively. State P2 corresponds to the cross-transmission of 1410nm light in the X-shaped cross waveguide, and the straight-through transmission of 1520nm light. At this time, the refractive indices of the key dielectric pillars 1, 2, 3 and 4 at the center of the cross waveguide are 3.7, 5, 3.7 and 5, respectively. Figure 4 This describes the optical field distribution and transmission spectrum of light at different output ports when light of wavelengths of 1410nm, 1520nm, and 1550nm is incident from port N1. Figure 4 It can be seen that when light of 1410nm, 1520nm, and 1550nm is incident from port N1, the 1410nm light is ultimately output from port S2, with a transmittance of 95.14% at port S2; the 1520nm light is ultimately output from port E2, with a transmittance of 92.36% at port E2; and the 1550nm light is ultimately output from port W2, with a transmittance of 90.40% at port W2. Therefore, this router achieves wavelength selection routing for three wavelengths and has high transmission efficiency. The crosstalk of the entire router is -26.1 to -9.47 dB, and the insertion loss is 0.43 to 0.88 dB.

[0055] Example 4:

[0056] This embodiment is basically the same as the above embodiments, with the following differences:

[0057] This implementation is used to achieve non-blocking routing of 1550nm optical signals.

[0058] See Figure 1 , Figure 2 and Figure 3 A photonic crystal router for Mesh on-chip optical networks is described. Its basic structure is a two-dimensional photonic crystal with square lattice dielectric pillars, with 95 horizontal and 59 vertical dielectric pillars. Ports W1, N1, E1, and S1 are input ports, and ports W2, N2, E2, and S2 are output ports. The background is air, and the dielectric pillar material is Ge2Sb2Se4Te1 (GSST), a phase-change material with low absorption characteristics in the optical communication wavelength range. External excitation (such as laser pulse irradiation) is used to achieve rapid transitions between different states of the material, flexibly controlling the refractive index of the dielectric pillars. In both the 2×4 and 2×2 basic units, the cross-waveguide width is... The spacing between dielectric pillars at the edge of the cross waveguide is The lattice constant a = 0.58 μm, and the refractive index and radius of the background dielectric pillars are n = 3.46 and R = 0.08 μm, respectively. The radii of dielectric pillars 2 and 4 at the center of the cross waveguide are 0.115 μm, and the radii of dielectric pillars at other locations are the same as those of the background dielectric pillars.

[0059] Table 2 shows the nine non-blocking routing transmission states of the router when 1550nm light is input from ports W1, N1, E1, and S1. Each routing state includes four specified paths and the corresponding working state of each cross waveguide.

[0060] Table 2. Optical links and operating states of each cross waveguide when light is input from different ports.

[0061]

[0062] In Table 2, the refractive indices of the key dielectric pillars 1, 2, 3 and 4 at the center of the cross-transmission state are 5.1, 3.9, 5.1 and 3.9, respectively; and the refractive indices of the key dielectric pillars 1, 2, 3 and 4 at the center of the cross-transmission state are 4.7, 3.4, 3.9 and 3.4, respectively.

[0063] Because the router's structure is symmetrical both vertically and horizontally, the end-to-end non-blocking optical routing transmission includes five independent and non-repeating optical links: A, B, C, D, and E. Link A: Input at port W1, passes through three cross-waveguides, and outputs at port S2. Link B: Input at port W1, passes through three cross-waveguides, and outputs at port N2. Link C: Input at port W1, passes through four cross-waveguides, and outputs at port E2. Link D: Input at port N1, passes through four cross-waveguides, and outputs at port S2. Link E: Input at port W1, passes through five cross-waveguides, and outputs at port S2. The permutations and combinations of these five independent and non-repeating links constitute all 36 links for the nine non-blocking states. Figure 5-9The figures show the optical field distribution and transmission spectrum at each output port for optical links A, B, C, D, and E, respectively. For link A, the cross waveguides M1.1, M1.3, and D2 are all in a straight-through state, with a transmittance of 94.37% for 1550nm light at port S2. For link B, the cross waveguides M1.1, M1.2, and D1 are in a cross-through state, a straight-through state, and a cross-through state, respectively, with a transmittance of 95.93% for 1550nm light at port N2. For link C, the cross waveguides M1.1, M1.2, M2.2, and M2.1 are all in a cross-through state, with a transmittance of 95.93% for 1550nm light at port N2. The transmittance of 0nm light at port E2 is 94.90%. For link D, the cross waveguides D1, M2.2, M2.3, and D2 are all in cross-connected state, and the transmittance of 1550nm light at port S2 is 96.59%. For link E, the cross waveguides M1.1, M1.2, M2.2, M2.3, and D2 are in cross-connected, cross-connected, pass-through, cross-connected, and cross-connected states respectively, and the transmittance of 1550nm light at port S2 is 92.97%. At a working wavelength of 1550nm, the signal-to-noise ratio for non-blocking transmission of the entire router is 17.84–20.06 dB.

[0064] As shown above, by appropriately selecting the refractive indices of the four dielectric pillars at the center of the cross waveguides and adjusting the operating states of each cross waveguide, wavelength-selective routing functions for 1410nm, 1520nm, and 1550nm optical signals, as well as end-to-end non-blocking routing functions for 1550nm optical signals, can be achieved.

[0065] In summary, the photonic crystal router with a cross-waveguide structure of this invention consists of two 2×4 routing basic units and two 2×2 routing basic units, each containing only a cross-waveguide structure. The 2×4 routing basic unit comprises three cross-waveguide structures including horizontal input and output waveguides; the 2×2 routing basic unit is a cross-waveguide structure including vertical input and output waveguides. The entire router structure is vertically and horizontally symmetrical. A phase-change material is selected as the dielectric pillar material. By flexibly adjusting the refractive index of the key dielectric pillar at the center of the cross-waveguide structure, this structure can be applied to Mesh on-chip optical networks to achieve full-link non-blocking routing and wavelength-selective routing functions. Compared with existing 4×4 photonic crystal routers, this router has richer routing functions and features a simple structure, high transmission efficiency, and ease of implementation, making it important for applications in all-optical communication and on-chip networks.

[0066] The embodiments of the present invention have been described above in conjunction with the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made according to the purpose of the invention. Any changes, modifications, substitutions, combinations or simplifications made based on the spirit and principle of the technical solution of the present invention shall be equivalent substitutions. As long as they meet the purpose of the invention and do not deviate from the technical principle and inventive concept of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. A photonic crystal router applied to a mesh optical network on chip, characterized in that: The two-dimensional photonic crystal adopts a square lattice dielectric pillar type and consists of two 2×4 basic units (M1, M2) placed symmetrically on the left and right and two 2×2 basic units (D1, D2) placed symmetrically on the top and bottom; all basic units are composed of X-shaped cross waveguide structures. The two 2×4 basic units (M1, M2) each contain three X-shaped cross waveguide structures: In the first 2×4 basic unit (M1), the first X-shaped cross waveguide structure (M1.1) is located on the left, and the second X-shaped cross waveguide structure (M1.2) and the third X-shaped cross waveguide structure (M1.3) are located on the right side of the first X-shaped cross waveguide structure (M1.1), symmetrically placed vertically. Since the two 2×4 basic units (M1, M2) are symmetrical horizontally, in the second 2×4 basic unit (M2), the first X-shaped cross waveguide structure (M2.1) is located on the right, and the second X-shaped cross waveguide structure (M2.2) and the third X-shaped cross waveguide structure (M2.3) are located on the left side of the first X-shaped cross waveguide structure (M2.1), symmetrically placed vertically. The X-shaped cross waveguide structures (M1.1, M1.2, M1.3, M2.1, M2.2) The entire structure is an X-shaped cross waveguide with horizontal waveguides at four ports. The upper right port of the first X-shaped cross waveguide structure (M1.1) of the first 2×4 basic unit (M1) is connected to the upper left port of the second X-shaped cross waveguide structure (M1.2) of the first 2×4 basic unit (M1); the lower right port of the first X-shaped cross waveguide structure (M1.1) of the first 2×4 basic unit (M1) is connected to the lower left port of the third X-shaped cross waveguide structure (M1.3) of the first 2×4 basic unit (M1); and the lower left port of the second X-shaped cross waveguide structure (M1.2) of the first 2×4 basic unit (M1) is connected to the upper left port of the third X-shaped cross waveguide structure (M1.3) of the first 2×4 basic unit (M1), thus forming the first 2×4 basic unit (M1). The upper left port of the first X-shaped cross waveguide structure (M2.1) of the second 2×4 basic unit (M2) is connected to the upper right port of the second X-shaped cross waveguide structure (M2.2) of the second 2×4 basic unit (M2); the lower left port of the first X-shaped cross waveguide structure (M2.1) of the second 2×4 basic unit (M2) is connected to the lower right port of the third X-shaped cross waveguide structure (M2.3) of the second 2×4 basic unit (M2); and the lower right port of the second X-shaped cross waveguide structure (M2.2) of the second 2×4 basic unit (M2) is connected to the upper right port of the third X-shaped cross waveguide structure (M2.3) of the second 2×4 basic unit (M2), thus forming the second 2×4 basic unit (M2). The two ports of the 2×2 basic unit (D1, D2) are respectively connected to the outer ports of the two 2×4 basic units (M1, M2) on the left and right.

2. The photonic crystal router for use in a Mesh-on-a-chip optical network according to claim 1, characterized in that: The two middle ports of the two 2×4 basic units (M1, M2) are interconnected.

3. The photonic crystal router for Mesh on-chip optical networks according to claim 1, characterized in that: The 2×2 basic unit (D1, D2) is an X-shaped cross waveguide with vertical waveguides at four ports.

4. The photonic crystal router for Mesh on-chip optical networks according to any one of claims 1-3, characterized in that: The X-shaped cross waveguide consists of two waves perpendicular to the horizontal direction at a 45° angle. ° The waveguides are orthogonally constructed, and the width of the cross waveguide is... The spacing between adjacent dielectric pillars at the edge of the cross waveguide is , where a is the lattice constant of the background medium column.

5. The photonic crystal router for Mesh on-chip optical networks according to any one of claims 1-3, characterized in that: In the entire router structure, except for the dielectric pillars (2) and (4), whose radii differ from the background dielectric pillars, the radii of the other dielectric pillars are the same as the background dielectric pillars; the refractive indices of the key dielectric pillars at each X-shaped cross waveguide center are different.

6. The photonic crystal router for Mesh on-chip optical networks according to claim 1, characterized in that: The entire structure is symmetrical both vertically and horizontally, with a total of eight ports in four directions. Two ports in each direction can be used as input ports or output ports. When one port is an input port, the other port is an output port.

7. The photonic crystal router for Mesh on-chip optical networks according to claim 1, characterized in that: By selecting the appropriate refractive index of the key dielectric pillar at the center of each cross waveguide structure, wavelength selection routing for input light of different wavelengths can be achieved.

8. The photonic crystal router for Mesh on-chip optical networks according to claim 1, characterized in that: By selecting the appropriate refractive index of the key dielectric pillar at the center of each cross waveguide structure, nine states of unobstructed optical routing can be achieved.

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