Multiband electro-optical NOT gate based on MIM waveguide and VO2 phase change

Abstract

The invention relates to the technical field of metal micro-nano optical devices and electro-optical integration, in particular to a multi-band electro-optical NOT gate based on MIM waveguide and VO2 phase change in the technical field of integrated circuit optical networks and on-chip optical computing. The device structure comprises an MIM single waveguide-circular resonator formed by taking metal silver as a substrate, and a VO2 micro-nano ring and an electrode regulation and control unit which are attached to the outside of the circular resonator. The time domain finite difference method (FDTD) and the finite element method (FEM) are adopted for verification, the VO2 electro-insulator-metal phase change characteristic is utilized, the multi-band plasma resonance effect of the MIM circular resonator is combined, and electric control on-off of optical signals is achieved in the nanometer size. The single-input single-output electro-optical NOT logic operation can be realized, and 800-1800nm multi-band work can be supported by depending on the multi-formant characteristic. The method has great application prospects in the fields of on-chip optical communication, ultra-compact photon integration, micro-nano sensing and optical calculation, and provides efficient and flexible information processing capacity for integrated electro-optical logic regulation and control.

Description

A multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition Technical Field

[0001] This invention relates to the field of metal micro-nano optical devices and electro-optic integration technology, and particularly to a multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition in the field of devices that utilize electro-optic modulation technology to realize logic operation functions and optical signal processing related technologies. Background Technology

[0002] With the rapid development of 6G communication and artificial intelligence technologies, optoelectronic devices are evolving towards high integration, small size, low power consumption, and multifunctional integration, placing higher demands on the information processing capabilities of nanoscale optical devices. Traditional optical devices, limited by the diffraction limit, struggle to meet the application requirements of high-density integrated photonic systems. Surface plasmon polaritons (SPPs) can overcome the diffraction limit, localizing electromagnetic fields at the subwavelength scale, providing an important technological path for realizing nanophotonic integration. Therefore, micro- and nano-optoelectronic devices based on surface plasmon polaritons have attracted widespread research and attention.

[0003] Metal-insulator-metal (MIM) waveguide structures can confine the optical field within an intermediate dielectric layer, enabling low-loss, high-confinement optical transmission at the nanoscale. They are a commonly used fundamental structure for constructing surface plasmon resonance (SPR) functional devices. In recent years, numerous functional devices based on MIM waveguides have been proposed and applied in optical communication, optical sensing, and optical information processing, including filters, high-sensitivity biosensors, multi-channel optical interconnect splitters and demultiplexers, and optical logic devices.

[0004] MIM waveguide-based optical logic gates are the core units for on-chip optical signal processing, attracting widespread attention due to their compact structure and ease of integration with nanophotonic circuits. MIM waveguide logic gates typically achieve their logic functions by controlling the coupling strength and interference effect between the waveguide and the resonator.

[0005] The electromodulation path directly triggers abrupt changes in the physical properties of electro-optic materials by applying voltage or current, thereby achieving precise dynamic control of the equivalent refractive index. It has the advantages of not requiring a high-power pump light source, extremely low overall power consumption, fast control response speed, and strong compatibility with traditional microelectronic circuits, making it the mainstream development direction for reconfigurable optical logic devices.

[0006] MIM waveguides, leveraging the surface plasmon effect, possess unique advantages such as strong subwavelength field localization, excellent optical field confinement, extremely low bending loss due to small size, operating band covering visible to mid-infrared light, and flexible and tunable structural design, making them perfectly suited for high-density nanophotonic integrated systems. Furthermore, combining electromodulation technology with MIM waveguide logic gates creates bidirectional technical gains. On one hand, MIM waveguides overcome the diffraction limit, enabling submicron-level ultra-compact device layouts; on the other hand, electromodulation achieves dynamic and controllable regulation, completely eliminating the functional rigidity and size dependence defects of all-optical logic gates. Compared to traditional all-optical logic gates, these electro-optic logic gates can achieve optical signal on / off and logic state switching without modifying the device's physical structure, offering higher tolerance for fabrication process tolerances, significantly reducing processing difficulty, and greatly improving versatility. Summary of the Invention

[0007] The purpose of this invention is to provide a multi-band electro-optic NOT gate based on MIM waveguides and VO2 phase transition, aiming to solve the problems of complex structure, high power consumption, poor compatibility, and insufficient multi-band control capability of existing optical logic gates, and to realize nanoscale, low power consumption, multi-band operation electro-optic NOT logic operation, adapting to the needs of on-chip photonic integration and optical computing.

[0008] To achieve the above objectives, this invention provides a multi-band electro-optic NOT gate based on MIM waveguides and VO2 phase transition, comprising: a MIM single-waveguide-circular resonator combination structure with silver as the metal substrate and air as the intermediate dielectric layer disposed on the substrate; and a VO2 phase transition electro-regulation unit disposed in the resonator region to control the resonant coupling and on / off transmission of optical signals via voltage signals. This structure has only a single input waveguide port and a single output waveguide port. An external voltage triggers an insulator-metal phase transition in the VO2 material, changing the equivalent refractive index of the micro / nano ring and precisely controlling the resonant coupling transmission state of the optical signal. This achieves single-waveguide, low-power, high-contrast electro-optic NOT logic operation at the nanoscale. Simultaneously, relying on the multi-resonance peak characteristics of the resonator, it realizes multi-band tunable NOT logic functions within a wide wavelength range of 800nm-1800nm. By employing the finite-difference time-domain (FDTD) and finite element method (FEM) to complete device simulation optimization and performance verification, the complex design of traditional multi-port input is abandoned. Optical signal transmission is completed through only single-port input and single-port output. With the help of external voltage regulation, efficient switching and logic state reversal of the output optical signal are achieved.

[0009] Furthermore, the MIM single waveguide-circular resonator has a three-layer structure of metal-air-metal, with the upper and lower metal layers made of silver and the middle insulating dielectric layer being air.

[0010] Furthermore, in the MIM single waveguide-circular resonator structure, the air slit widths in the horizontal direction of the VO2 micro / nano ring and the MIM single waveguide are consistent.

[0011] Furthermore, the width of the VO2 micro-nano ring is 50 nm, and the width of the air slit in the horizontal direction of the MIM single waveguide is 50 nm.

[0012] Furthermore, the circular resonator has a horizontal radius of 340 nm, the VO2 micro-nano ring has a maximum outer radius of 390 nm, and the minimum inner radius is designed to be 340 nm.

[0013] Furthermore, the VO2 micro / nano ring and the MIM single waveguide are placed horizontally and coaxially, and the two are on the same horizontal axis of symmetry. The coupling gap between the VO2 micro / nano ring and the single waveguide is set to 10nm to ensure efficient coupling and stable transmission of optical signals.

[0014] Furthermore, the voltage signal control unit uses VO2 material with electro-insulator-metal phase transition properties to form a VO2 micro / nano ring structure concentrically attached to the circular resonator.

[0015] Furthermore, the voltage signal control unit adds electrodes to the upper and lower sides of the material. By applying an external voltage, a rapid reversible phase transition of the VO2 material from an insulating state to a metallic state is triggered.

[0016] Furthermore, the optical signal is input through a single input port; when no external voltage is applied, VO2 is in an insulating state with a high refractive index, and the optical signal is efficiently transmitted to the output port, with the output end exhibiting a logic "1" state with high transmittance in multiple bands; after the rated voltage is applied, VO2 quickly transforms into a metallic state, the refractive index drops sharply, the resonance condition is destroyed, the optical signal coupling transmission is blocked, and the output end exhibits a logic "0" state with low transmittance, realizing the complete reversal of the input and output optical signals and completing the electro-optic NOT logic operation.

[0017] This invention provides a multi-band electro-optic NOT gate based on MIM waveguides and VO2 phase transition, comprising: a MIM single-waveguide-circular resonator combination structure with air as an intermediate dielectric layer disposed on a silver metal substrate; and a VO2 phase transition electro-regulation unit disposed in the resonator region to control the resonant coupling and on / off transmission of optical signals via voltage signals. Compared with existing technologies, its significant advantages are: extremely simple structure, high integration, single-waveguide single-port input / output design, and compact overall device size; efficient regulation and excellent performance, relying on the low-voltage electro-induced phase transition of VO2 for regulation, resulting in low regulation voltage, extremely low power consumption, fast response speed, and high logic contrast; and leveraging the multi-resonance peak characteristics of the MIM air dielectric resonator to support multi-band adjustable operation from 800nm ​​to 1800nm, flexibly adapting to different optical communication and optical sensing bands, and applicable to a wider range of scenarios. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 is a schematic diagram of a multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition according to the present invention.

[0020] Figure 2 is a schematic diagram of a multi-band electro-optic NOT gate signal transmission coupling structure based on MIM waveguide and VO2 phase transition according to the present invention.

[0021] Figure 3 is a schematic diagram of the effective dielectric refractive index and size of a multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition according to the present invention.

[0022] Figure 4 is a transmittance transmission diagram of a multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition according to the present invention.

[0023] 1-Signal transmission input waveguide, 2-Signal transmission output waveguide, 3-Air circular resonator, 4-Voltage signal control unit VO2 micro / nano ring, 5-Silver dielectric substrate. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this application clearer, embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0025] Please refer to Figures 1 to 4. This invention provides a multi-band electro-optic NOT gate based on MIM waveguides and VO2 phase transition, comprising: a MIM single-waveguide-circular resonator combination structure with silver as the metal substrate and air as the intermediate dielectric layer disposed on the substrate; and a VO2 phase transition electro-regulation unit disposed in the resonator region to control the resonant coupling and on / off transmission of optical signals via voltage signals. This structure has only a single input waveguide port and a single output waveguide port. By triggering the VO2 material to undergo an insulator-metal phase transition through an external voltage, the equivalent refractive index of the micro / nano ring is changed, and the resonant coupling transmission state of the optical signal is precisely controlled. This achieves single-waveguide, low-power, and high-contrast electro-optic NOT logic operation at the nanoscale. At the same time, relying on the multi-resonance peak characteristics of the resonator, it realizes multi-band tunable NOT logic functions in a wide wavelength range of 800nm-1800nm. By employing the Finite-Difference Time-Domain (FDTD) and Finite Element Method (FEM) to complete device simulation optimization and performance verification, the complex design of traditional multi-port input is abandoned. Optical signal transmission is completed through only single-port input and single-port output. With the help of external voltage regulation, efficient switching and logic state reversal of the output optical signal are achieved without modifying the physical structure of the device to complete the multi-band NOT logic function.

[0026] More specifically, in one embodiment, the MIM single waveguide-circular resonator has a three-layer structure of metal-air-metal, where the upper and lower metal layers are made of silver, and the middle insulating dielectric layer is air.

[0027] More specifically, in one embodiment, in the MIM single waveguide-circular resonator structure, the air slit widths in the horizontal direction of the VO2 micro / nano ring and the MIM single waveguide are the same.

[0028] More specifically, in one embodiment, the width of the VO2 micro / nano ring is 50 nm, and the width of the air slit in the horizontal direction of the MIM single waveguide is 50 nm.

[0029] More specifically, in one embodiment, the circular resonator has a horizontal radius of 340 nm, the VO2 micro-nano ring has a maximum outer radius of 390 nm, and the minimum inner radius is designed to be 340 nm.

[0030] More specifically, in one embodiment, the VO2 micro / nano ring and the MIM single waveguide are placed horizontally and coaxially, both on the same horizontal axis of symmetry. The coupling gap between the VO2 micro / nano ring and the single waveguide is set to 10 nm to ensure efficient coupling and stable transmission of optical signals.

[0031] More specifically, in one embodiment, the voltage signal control unit uses VO2 material with electro-insulator-metal phase transition properties to form a VO2 micro / nano ring structure concentrically attached to the circular resonator.

[0032] More specifically, in one embodiment, the voltage signal control unit electrodes are located on the upper and lower sides of the material, and by applying an external voltage, a rapid reversible phase transition of the VO2 material from an insulating state to a metallic state is triggered.

[0033] More specifically, in one embodiment, the optical signal is input through a single input port; when no external voltage is applied, VO2 is in an insulating state with a high refractive index, and the optical signal is efficiently transmitted to the output port, with the output end exhibiting a logic "1" state with high transmittance in multiple bands; after the rated voltage is applied, VO2 quickly transforms into a metallic state, the refractive index drops sharply, the resonance condition is destroyed, the optical signal coupling transmission is blocked, and the output end exhibits a logic "0" state with low transmittance, realizing the complete reversal of the input and output optical signals and completing the electro-optic NOT logic operation.

[0034] This invention also provides a specific embodiment and simulation experiment for illustration: As a specific example, the invention is further illustrated by referring to Figure 1. The multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition includes a MIM single waveguide-circular resonator combination structure formed by an air slit on a silver substrate, and a VO2 phase transition electro-control unit disposed in the resonator region. The incident light source is a TM-polarized plane wave, incident forward along a single input port. Two control states are achieved by having or not having an external voltage. When the optical signal is at the 860nm operating wavelength, the signal transmittance is ≥0.5 without voltage control, and the transmittance is ≤0.1 after applying voltage control. Moreover, the same NOT logic function can be achieved in multiple resonance peak bands at 1120nm and 1600nm, verifying the multi-band operating characteristics of the device.

[0035] In this way, by regulating the VO2 phase transition by voltage, multi-band electro-optic NOT logic operations can be realized without changing the device structure size and light source parameters, adapting to the integrated application needs of scenarios such as on-chip optical computing and high-speed optical communication.

[0036] The above description discloses only one preferred embodiment of the present invention, and should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition, characterized in that, It includes a silver substrate for SPP excitation, a MIM single waveguide-circular resonator structure disposed on the silver substrate, a voltage signal modulation unit attached to the outside of the circular resonator structure, and a single light source input port disposed in the waveguide structure and an output port disposed at the other end of the structure as signal coupling. The MIM single waveguide-circular resonator structure, the voltage signal modulation unit, and the silver substrate are placed at the same horizontal height. The voltage signal modulation unit is constructed by depositing a VO2 micro / nano ring and fabricating microelectrodes outside the circular resonator. By applying a voltage signal to the electrodes, the insulator-metal phase transition of VO2 is triggered, changing the equivalent refractive index of the VO2 micro / nano ring, thereby modulating the optical signal coupling state between the resonator and the MIM single waveguide, realizing single-input single-output electro-optic NOT logic operation. Furthermore, the MIM single waveguide and circular resonator coupling structure has multiple resonant transmission peaks in the 800nm-1800nm ​​band that can be modulated by VO2.

2. The multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition as described in claim 1, characterized in that, The VO2 micro-nano ring and the circular resonator are concentric.

3. A multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition as described in claim 2, characterized in that, The width of the rectangular waveguide in the MIM single waveguide-circular resonator structure is equal to that of the VO2 micro / nano ring in the horizontal plane.

4. A multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition as described in claims 2 and 3, characterized in that, The width of the VO2 micro-nano ring is 50 nm, and the width of the rectangular waveguide in the horizontal direction is 50 nm.

5. A multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition as described in claims 2, 3, and 4, characterized in that, The radius of the circular resonator in the horizontal direction is 340 nm.

6. A multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition as described in claims 2, 3, 4, and 5, characterized in that, The VO2 micro-nano ring has a maximum outer radius of 390 nm and a minimum inner radius of 340 nm.

7. A multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition as described in claims 1 to 6, characterized in that, The signal coupling interface between the VO2 micro / nano ring and the single waveguide is set as a horizontal tangent structure, and the structures are on the same horizontal axis of symmetry to achieve efficient waveguide coupling and transmission of optical signals.

8. A multi-band electro-optic NOT gate based on MIM waveguide and VO2 phase transition as described in claims 1 to 7, characterized in that, The microelectrodes are positioned above and below one side of the VO2 micro-nano ring. A voltage signal is applied to trigger the VO2 phase transition. When VO2 is in an insulating state, the optical signal corresponding to the resonant wavelength is transmitted and output through the MIM waveguide. When VO2 is in a metallic state, the resonant condition is destroyed, the optical signal is suppressed and cannot be output, thereby realizing the NOT logic operation.

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