Logic OR gate device based on double-graphene rectangular resonant cavity edge coupling waveguide
Through a logic OR gate device based on a double graphene rectangular resonant cavity side coupled waveguide, the problems of low extinction ratio, large device size and slow response rate of all-optical logic gate devices are solved, and logic OR gate devices with high extinction ratio, high contrast and ultra-fast response rate are realized, which are suitable for all-optical communication networks and all-optical signal processing.
Patent Information
- Application Number
- CN202421936791.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-12
- Publication Date
- 2025-07-04
- Estimated Expiration
- 2034-08-12
AI Technical Summary
In the prior art, all-optical logic gate devices have problems such as low extinction ratio and contrast, large device size, slow response rate and difficult to integrate, especially in all-optical communication networks and all-optical signal processing.
A logic or gate device based on a double graphene rectangular resonant cavity edge coupling waveguide is adopted, including a silicon substrate, a sapphire layer, a graphene nanobar waveguide and a graphene rectangular resonant cavity. The edge coupling structure is formed by a graphene nanobar waveguide and a rectangular resonant cavity arranged in parallel, and the logic output is controlled by combining the graphene chemical potential.
It realizes the ultra-compact size of the logic OR gate device, less than 0.05μm2, high extinction ratio and high contrast ratio, ultra-fast response rate of 1ps, and easy to integrate logic OR gate devices.
Smart Images
Figure CN223065625U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of all-optical communication networks, and particularly relates to a logic OR gate device based on a side-coupled waveguide of a double-graphene rectangular resonant cavity. Background Art
[0002] In an all-optical communication network, an all-optical logic gate is a key component for realizing functions such as optical signal calculation, optical signal switching, all-optical address recognition, and all-optical signal extraction. With the rapid development of large-scale integrated photonic devices, the requirements for small size, high extinction ratio, high contrast, and ultra-fast speed of optical logic gates are becoming increasingly obvious. Therefore, it is very important to realize an all-optical logic gate device with a new working mechanism that has a compact device size, a high extinction ratio, a high contrast, an ultra-fast response rate, and is easy to integrate. Such new types of optical logic gate devices are increasingly widely used in all-optical communication networks and all-optical signal processing.
[0003] Surface Plasmon Polaritons (SPPs for short) are a kind of surface electromagnetic evanescent wave that propagates along the metal–dielectric interface and decays exponentially in the direction perpendicular to the metal surface. SPPs have the characteristics of being able to break through the traditional optical diffraction limit and having a strong local optical field enhancement, so that light can be guided and manipulated at the sub-wavelength scale. The SPP wave can be used as a carrier of energy and information, and it has important application value in high-density integrated photonic circuits.
[0004] Currently, optical logic gate devices based on SPPs have been widely studied, such as Mach–Zehnder interferometers (MZIs) and micro-ring resonator structures. In 2014, researchers such as K.J.A. Ooi proposed a graphene surface plasmon logic gate based on a Mach–Zehnder interferometer in the mid-infrared band. This logic gate has a compact device size and a relatively high average extinction ratio (15 dB). In 2015, researchers such as T. Birr realized ultra-fast all-optical AND, OR, NOT, and XOR gates by using the linear interference between dielectric cross waveguides. The size of the device reached 10 μm × 20 μm, and a half adder was realized based on this logic gate. Recently, researchers such as B. Zhu studied a magnetically controlled graphene logic gate device in a bilayer graphene waveguide structure based on the principle of non-reciprocal coupling. The minimum extinction ratios of the OR gate and AND gate designed by them reached 13.6 dB and 17.5 dB respectively. Therefore, realizing an SPP optical logic gate device with a compact device size, a high extinction ratio, a high contrast, an ultra-fast response rate, and easy integration is the future development trend of all-optical communication technology.
[0005] In recent years, graphene, a two-dimensional material composed of a single layer of carbon atoms, has provided a novel and low-loss way to confine and control surface plasmon polaritons (SPPs) waves, and thus has been widely used in the design of SPPs devices. Experimental studies by A.E. Nikolaenko et al. have shown that graphene has an ultrafast response time on the order of 1 ps, which can effectively achieve an ultra-fast repetition rate for optical logic gate devices.
[0006] The defects of the prior art are as follows:
[0007] 1. For traditional logic OR gate devices based on Mach-Zehnder interferometer (MZI) or microring resonator structures, the obtained average extinction ratio and contrast ratio are relatively low, which limits the application and development of logic OR gate devices in all-optical signal processing technologies.
[0008] 2. For traditional logic OR gate devices based on dielectric cross-waveguide structures, the device size is large, which is not conducive to large-scale integration of the devices.
[0009] 3. Due to the slow response rate of traditional materials, the response rate of logic OR gate devices is reduced, which is not conducive to the application and development of ultra-fast logic OR gate devices in broadband high-speed optical communication networks and all-optical signal processing technologies.
[0010] 4. Since actual logic OR gate devices should be three-dimensional and fabricated on a substrate, but many of the proposed device structures currently only study two-dimensional planar structures and do not consider the thickness of the metal film and out-of-plane losses, which is not conducive to the structural design and performance analysis of logic OR gate devices. Summary of the Invention
[0011] The present utility model aims at the above problems and provides a logic OR gate device based on a dual-graphene rectangular resonator edge-coupled waveguide, aiming to achieve a logic OR gate device with a compact device size, a high extinction ratio, a high contrast ratio, an ultra-fast response rate, and easy integration.
[0012] To solve the above problems, the technical solution provided by the present utility model is as follows:
[0013] A logic OR gate device based on a dual-graphene rectangular resonator edge-coupled waveguide includes a silicon substrate, a sapphire layer, graphene nanoribbon waveguides, and graphene rectangular resonators, wherein: the sapphire layer is disposed above the silicon substrate; the graphene nanoribbon waveguides and the graphene rectangular resonators are disposed on the upper surface of the sapphire layer.
[0014] The graphene nanoribbon waveguides include a first graphene nanoribbon waveguide and a second graphene nanoribbon waveguide.
[0015] The first graphene nanoribbon waveguide and the second graphene nanoribbon waveguide are arranged in sequence from front to back.
[0016] The graphene rectangular resonator includes a first graphene rectangular resonator and a second graphene rectangular resonator.
[0017] The first graphene rectangular resonator and the second graphene rectangular resonator are arranged in parallel; the first graphene rectangular resonator and the second graphene rectangular resonator are respectively disposed on the left and right sides of the graphene nanoribbon waveguide, and form an edge-coupling structure with the graphene nanoribbon waveguide.
[0018] The chemical potential of the graphene nanoribbon waveguide is fixed at 0.6 eV.
[0019] When the chemical potentials of the first graphene rectangular resonator and the second graphene rectangular resonator are fixed at 0.60 eV, the logic output by this logic exclusive-OR gate is "1".
[0020] When the chemical potentials of the first graphene rectangular resonator and the second graphene rectangular resonator are fixed at 0.2 eV, the logic output by this logic exclusive-OR gate is "0".
[0021] Preferably, the thickness of the silicon substrate is 300 nm; the thickness of the sapphire layer is 300 nm; the length of the first graphene rectangular resonator is 140 nm and the width is 10 nm; the length of the second graphene rectangular resonator is 140 nm and the width is 10 nm; the width of the first graphene nanoribbon waveguide is 10 nm; the width of the second graphene nanoribbon waveguide is 10 nm.
[0022] Preferably, the refractive index and loss factor of the sapphire layer are 1.60 and 0.0004 respectively at a wavelength of 5.37 μm.
[0023] Preferably, the coupling distance between the graphene nanoribbon waveguide and the graphene rectangular resonator is 10 nm.
[0024] Preferably, the coupling length between the first graphene nanoribbon waveguide and the first graphene rectangular resonator is 60 nm; the coupling length between the second graphene nanoribbon waveguide and the second graphene rectangular resonator is 60 nm.
[0025] Preferably, the distance between the first graphene nanoribbon waveguide and the second graphene nanoribbon waveguide is 20 nm; the distance from the dipole exciting the surface plasmon polariton to the center of the graphene rectangular resonator is 150 nm; the distance between the center of the graphene rectangular resonator and the detector is 150 nm.
[0026] Preferably, the relaxation time of the graphene used in the present utility model is 0.5 ps; the thickness of a single layer of the graphene is 0.2 nm.
[0027] Compared with the prior art, the utility model has the following advantages:
[0028] 1. Since the utility model adopts a graphene nanostrip waveguide and a graphene rectangular resonant cavity structure, a double graphene rectangular resonant cavity edge-coupled waveguide system is applied to an integrated graphene logic OR gate device, thereby solving the problems of low extinction ratio and low contrast of the graphene logic OR gate device.
[0029] 2. Since the size of the logic or gate device based on the double graphene rectangular resonant cavity edge-coupled waveguide of the utility model is less than 0.05 μm 2 , which can realize an ultra-compact structure, thereby greatly reducing the size of the logic OR gate device and solving the problem that the logic OR gate device is not easy to integrate on a large scale in the on-chip plasmon optical path.
[0030] 3. Since the graphene response time used in the present invention is on the order of 1 ps, an ultra-fast response rate of the logic OR gate device is achieved. BRIEF DESCRIPTION OF THE DRAWINGS
[0031] Figure 1 It is a structural schematic diagram of a logic OR gate of a specific embodiment of the utility model;
[0032] Figure 2a It is a schematic diagram of the transmission spectrum of the logic OR gate when the logic input is "1 1" according to a specific embodiment of the utility model;
[0033] Figure 2b It is a schematic diagram of the transmission spectrum of the logic OR gate when the logic input is "1 0" according to a specific embodiment of the utility model;
[0034] Figure 2c This is a schematic diagram of the transmission spectrum of a logic OR gate when the logic input is “0 0” according to a specific embodiment of the present invention.
[0035] Wherein: 1. Silicon substrate, 2. Sapphire layer, 3. Graphene nanostrip waveguide, 4. Graphene rectangular resonant cavity, 3.1. First graphene nanostrip waveguide, 3.2. Second graphene nanostrip waveguide, 4.1. First graphene rectangular resonant cavity, 4.2. Second graphene rectangular resonant cavity, 5. Forward, 6. Backward DETAILED DESCRIPTION
[0036] The present invention is further explained below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.
[0037] like Figure 1As shown, a logic OR gate device based on a side-coupled waveguide of a double-graphene rectangular resonator includes a silicon substrate 1, a sapphire layer 2, a graphene nanoribbon waveguide 3, and a graphene rectangular resonator 4, where: The sapphire layer 2 is disposed above the silicon substrate 1; The upper surface of the sapphire layer 2 is provided with a graphene nanoribbon waveguide 3 and a graphene rectangular resonator 4.
[0038] The graphene nanoribbon waveguide 3 includes a first graphene nanoribbon waveguide 3.1 and a second graphene nanoribbon waveguide 3.2.
[0039] The first graphene nanoribbon waveguide 3.1 and the second graphene nanoribbon waveguide 3.2 are arranged in sequence from front to back.
[0040] The graphene rectangular resonator 4 includes a first graphene rectangular resonator 4.1 and a second graphene rectangular resonator 4.2.
[0041] The first graphene rectangular resonator 4.1 and the second graphene rectangular resonator 4.2 are arranged in parallel; The first graphene rectangular resonator 4.1 and the second graphene rectangular resonator 4.2 are respectively disposed on the left and right sides of the graphene nanoribbon waveguide 3 and form a side-coupling structure with the graphene nanoribbon waveguide 3.
[0042] The chemical potential of the graphene nanoribbon waveguide 3 is fixed at 0.6 eV.
[0043] When the chemical potentials of the first graphene rectangular resonator 4.1 and the second graphene rectangular resonator 4.2 are fixed at 0.60 eV, the logic output by this logic XOR gate is "1".
[0044] When the chemical potentials of the first graphene rectangular resonator 4.1 and the second graphene rectangular resonator 4.2 are fixed at 0.2 eV, the logic output by this logic XOR gate is "0".
[0045] It should be noted that in practical applications, the SPPs on the graphene nanoribbon waveguide 3 can be excited by a grating or a prism. In this utility model, a dipole is used to excite the surface plasmon of the boundary mode at the front end of the graphene nanoribbon waveguide 3, and a detector is arranged at the rear end of the graphene nanoribbon waveguide 3 to detect the SPPs wave.
[0046] It should be further noted that this invention adopts the method of simulation by FDTD–solution software to determine the structural parameters of the logic OR gate device based on the side-coupled waveguide of the double-graphene rectangular resonator.
[0047] In this specific embodiment, the thickness of the silicon substrate 1 is 300 nm; the thickness of the sapphire layer 2 is 300 nm; the length of the first graphene rectangular resonator 4.1 is 140 nm, and the width is 10 nm; the length of the second graphene rectangular resonator 4.2 is 140 nm, and the width is 10 nm; the width of the first graphene nanoribbon waveguide 3.1 is 10 nm; the width of the second graphene nanoribbon waveguide 3.2 is 10 nm.
[0048] In this specific embodiment, the refractive index and loss factor of the sapphire layer 2 are 1.60 and 0.0004 respectively at a wavelength of 5.37 μm.
[0049] In this specific embodiment, the coupling distance between the graphene nanoribbon waveguide 3 and the graphene rectangular resonator 4 is 10 nm.
[0050] In this specific embodiment, the coupling length between the first graphene nanoribbon waveguide 3.1 and the first graphene rectangular resonator 4.1 is 60 nm; the coupling length between the second graphene nanoribbon waveguide 3.2 and the second graphene rectangular resonator 4.2 is 60 nm.
[0051] In this specific embodiment, the distance between the first graphene nanoribbon waveguide 3.1 and the second graphene nanoribbon waveguide 3.2 is 20 nm; the distance from the dipole exciting the surface plasmon polariton to the center of the graphene rectangular resonator 4 is 150 nm; the distance between the center of the graphene rectangular resonator 4 and the detector is 150 nm.
[0052] In this specific embodiment, the relaxation time of the graphene used in this utility model is 0.5 ps; the thickness of the single-layer graphene is 0.2 nm.
[0053] In this specific embodiment, the size of the logic OR gate device based on the dual-graphene rectangular resonator edge-coupled waveguide is less than 0.05 μm 2 , and a super-compact graphene logic OR gate device can be realized.
[0054] It should be noted that in order to avoid the substrate loss of the light wave in the mid-infrared band, the substrate material used in the structure is sapphire Al2O3.
[0055] Such as Figure 2a 、 2b, as shown in 2c, it should be noted that when the logical input is "1 1", both the first graphene rectangular resonator 4.1 and the second graphene rectangular resonator 4.2 can be turned on, and the transmission distance is relatively short. The amplitude of the transmission peak at 5.31μm exceeds 0.70, and the extinction ratio at this time is -1.55dB. When the logical input is "1 0" or "0 1", since only one of the first graphene rectangular resonator 4.1 and the second graphene rectangular resonator 4.2 can be turned on, the amplitude of the transmission peak is significantly lower than that when the logical input is "1 1". At this time, the amplitude of the transmission peak at 5.31μm is reduced to 0.56, and the extinction ratio reaches -2.52dB. When the logical input is "0 0", since both the first graphene rectangular resonator 4.1 and the second graphene rectangular resonator 4.2 do not meet the phase matching condition and neither of the two rectangular resonators can be turned on, the transmittance at 5.31μm is reduced to 1.8×10 -3 , and the extinction ratio at this time reaches -27.50dB.
[0056] As shown in Table 1, the table shows the truth table and extinction ratio of the logic OR gate based on the edge-coupled waveguide of the double graphene rectangular resonator. The maximum difference in the extinction ratio between the output of 1 being turned on and the output of 0 being turned off reaches 25.95dB. The above simulation results show that the present invention can realize a graphene logic OR gate device with high extinction ratio and high contrast.
[0057] Table 1. Truth table and extinction ratio of the logic OR gate based on the edge-coupled waveguide of the double graphene rectangular resonator
[0058]
[0059] In the above detailed description, various features are combined in a single embodiment to simplify the present disclosure. This method of disclosure should not be interpreted as reflecting an intention that the embodiments of the claimed subject matter require more features than those clearly stated in each claim. On the contrary, as reflected by the appended claims, the present invention is in a state with fewer features than all the features of the disclosed single embodiment. Therefore, the appended claims are hereby clearly incorporated into the detailed description, where each claim stands alone as a separate preferred embodiment of the present invention.
[0060] In order for any person skilled in the art to implement or use the present invention, the above-described disclosed embodiments have been described. For those skilled in the art; various modification methods of these embodiments are obvious, and the general principles defined herein can also be applied to other embodiments without departing from the spirit and protection scope of the present disclosure. Therefore, the present disclosure is not limited to the embodiments given herein, but is consistent with the broadest scope of the principles and novel features disclosed in this application.
[0061] The foregoing description includes examples of one or more embodiments. Of course, it is not possible to describe all possible combinations of components or methods for the purpose of describing the above embodiments, but those of ordinary skill in the art should recognize that the various embodiments can be further combined and arranged. Therefore, the embodiments described herein are intended to cover all such changes, modifications, and variations that fall within the scope of the appended claims. In addition, with respect to the term "comprising" as used in the specification or claims, the word is to be construed in a manner similar to the term "including" as interpreted when used as a transitional word in a claim. In addition, any use of the term "or" in the claims or specification is intended to mean "non-exclusive or".
[0062] The specific embodiments described above further elaborate on the objectives, technical solutions, and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.
Claims
1. A logic OR gate device based on a side-coupled waveguide of a double graphene rectangular resonator, characterized in that: It includes a silicon substrate (1), a sapphire layer (2), a graphene nanoribbon waveguide (3), and a graphene rectangular resonator (4), where: the sapphire layer (2) is disposed above the silicon substrate (1); the graphene nanoribbon waveguide (3) and the graphene rectangular resonator (4) are disposed on the upper surface of the sapphire layer (2); The graphene nanoribbon waveguide (3) includes a first graphene nanoribbon waveguide (3.1) and a second graphene nanoribbon waveguide (3.2); The first graphene nanoribbon waveguide (3.1) and the second graphene nanoribbon waveguide (3.2) are arranged in sequence from front to back; The graphene rectangular resonator (4) includes a first graphene rectangular resonator (4.1) and a second graphene rectangular resonator (4.2); The first graphene rectangular resonator (4.1) and the second graphene rectangular resonator (4.2) are arranged in parallel; the first graphene rectangular resonator (4.1) and the second graphene rectangular resonator (4.2) are respectively disposed on the left and right sides of the graphene nanoribbon waveguide (3) and form an edge-coupling structure with the graphene nanoribbon waveguide (3); The chemical potential of the graphene nanoribbon waveguide (3) is fixed at 0.6 eV; When the chemical potentials of the first graphene rectangular resonator (4.1) and the second graphene rectangular resonator (4.2) are fixed at 0.60 eV, the logic output by this logic exclusive-OR gate is "1"; When the chemical potentials of the first graphene rectangular resonator (4.1) and the second graphene rectangular resonator (4.2) are fixed at 0.2 eV, the logic output by this logic exclusive-OR gate is "0".
2. The logic OR gate device based on the edge-coupled waveguide of a double graphene rectangular resonator according to claim 1, characterized in that: The thickness of the silicon substrate (1) is 300 nm; the thickness of the sapphire layer (2) is 300 nm; the length of the first graphene rectangular resonator (4.1) is 140 nm and the width is 10 nm; the length of the second graphene rectangular resonator (4.2) is 140 nm and the width is 10 nm; the width of the first graphene nanoribbon waveguide (3.1) is 10 nm; the width of the second graphene nanoribbon waveguide (3.2) is 10 nm.
3. The logic OR gate device based on the edge-coupled waveguide of a double graphene rectangular resonator according to claim 2, characterized in that: The refractive index and loss factor of the sapphire layer (2) at a wavelength of 5.37 μm are 1.60 and 0.0004 respectively.
4. The logic OR gate device based on the edge-coupled waveguide of a double graphene rectangular resonator according to claim 3, wherein: The coupling distance between the graphene nanoribbon waveguide (3) and the graphene rectangular resonator (4) is 10 nm.
5. The logic OR gate device based on the edge-coupled waveguide of a double graphene rectangular resonator according to claim 4, characterized in that: The coupling length between the first graphene nanoribbon waveguide (3.1) and the first graphene rectangular resonator (4.1) is 60 nm; the coupling length between the second graphene nanoribbon waveguide (3.2) and the second graphene rectangular resonator (4.2) is 60 nm.
6. The logic OR gate device based on the edge-coupled waveguide of a double graphene rectangular resonator according to claim 5, wherein: The distance between the first graphene nanoribbon waveguide (3.1) and the second graphene nanoribbon waveguide (3.2) is 20 nm; the distance from the dipole exciting surface plasmon polaritons to the center of the graphene rectangular resonator (4) is 150 nm; the distance between the center of the graphene rectangular resonator (4) and the detector is 150 nm.
7. The logic OR gate device based on the edge-coupled waveguide of a double graphene rectangular resonator according to claim 6, characterized in that: The relaxation time of the graphene used in this device is 0.5 ps; the thickness of the single-layer graphene is 0.2 nm.