A surface plasmon all-optical logic device

Abstract

The application discloses a surface plasmon all-optical logic device and a use method, belongs to the technical field of integrated circuits, utilizes the photorefractive effect of tungsten, has a femtosecond-level response time when femtosecond laser irradiates tungsten, thereby solving the slow operation defect of an electronic logic gate, and improving the computing capacity and signal transmission capacity. The application introduces tungsten into both sides of a waveguide and utilizes the photorefractive effect of tungsten as an innovation point; the all-optical logic device is optically modulated by tungsten, utilizes the characteristic that surface plasmons can break through the diffraction limit, realizes the operation and integration of all-optical logic gates on a nanometer scale, further reduces the size of all-optical logic gates, and the response time is all within 150 femtoseconds, thereby greatly improving the modulation speed. The application can be applied in the fields of optical computing and integrated optical regulation.

Description

Technical Field

[0001] This invention belongs to the field of integrated circuit technology, specifically relating to a surface plasmon all-optical logic device. Background Technology

[0002] With the increasing speed of the internet and the enhancement of computer capabilities, the heat generation and speed limitations of traditional electronic integrated circuits severely restrict the improvement of information processing speed. Compared with traditional electronic integrated circuits, photonic integrated circuits have many advantages, including transmitting information at the speed of light, wider communication bandwidth, carrying more information, generating less heat, better signal shielding, and lower crosstalk. Therefore, photonic integrated circuits represent the expectation for the next generation of computing systems. Photonic integrated circuits are composed of various types of photonic devices, typically including lasers, waveguides, switches, modulators, and detectors. In all-optical networks, the core unit for realizing all-optical information processing is the transmission, switching, and computation of light. All-optical logic gates are the core components of optical switching systems and key factors determining network performance; they serve as a bridge between electronic computing and optical computing, and quantum computing. Traditional all-optical logic gates were initially built on semiconductor materials. These electronic devices are limited by Moore's Law, so their size cannot be reduced to micro-nano precision. Utilizing the property of surface plasmons to overcome the diffraction limit, the operation and integration of all-optical logic gates can be realized at the nanoscale, further reducing the size of all-optical logic gates. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the present invention aims to provide a surface plasmonic all-optical logic device to solve the technical problem that the size of all-optical logic gates built on semiconductor materials in the prior art is limited by Moore's Law and cannot be reduced to micro-nano precision.

[0004] To achieve the above objectives, the present invention employs the following technical solution:

[0005] The present invention discloses a surface plasmon all-optical logic device, comprising: a substrate; grating couplers are respectively disposed at both ends of the substrate; a slit waveguide is disposed between the grating couplers on the substrate; and a first tungsten metal and a second tungsten metal for modulating light are also disposed at the slit waveguide on the substrate, wherein the first tungsten metal and the second tungsten metal are respectively disposed on both sides or at the end of the slit waveguide.

[0006] Preferably, the substrate is composed of SiO2 sheets, and silver is attached to the upper surface of the SiO2 sheets.

[0007] Preferably, the SiO2 sheet has a length of 55~75 μm and a width of 20~100 μm.

[0008] Preferably, the first and second tungsten metals modulate light through the photorefractive effect of tungsten metals.

[0009] Preferably, when there is one slit waveguide, the first tungsten metal and the second tungsten metal are respectively disposed on both sides of the slit waveguide and modulate the light to form an all-optical AND gate.

[0010] Preferably, when there are two slit waveguides, the first tungsten metal and the second tungsten metal are respectively disposed on both sides of the two slit waveguides and modulate the light to form an all-optical OR gate.

[0011] Preferably, when there are three slit waveguides, the first tungsten metal and the second tungsten metal are respectively disposed at the ends of the two slit waveguides in the middle and modulate the light to form an all-optical NOT gate.

[0012] This invention also discloses a method of using a surface plasmonic all-optical logic device, comprising:

[0013] S1: Select the appropriate all-optical logic device according to the function to be implemented;

[0014] S2: A femtosecond laser pulse is used as a control signal and is incident perpendicularly on the selected first and second tungsten metal surfaces to change their optical properties;

[0015] S3: A signal light oblique incidence grating coupler is used to realize the function of an all-optical logic gate.

[0016] Preferably, the femtosecond laser pulse in S2 has a wavelength of 1550nm and a pulse width of 120fs.

[0017] Preferably, the performance of the all-optical logic gate in S2 is controlled by the extinction ratio ER, wherein,

[0018]

[0019] It is the transmittance when the output logic is "1". It is the transmittance when the output logic is "0".

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] This invention discloses a surface plasmon optical logic device that utilizes the optical effect of tungsten metal. When tungsten is irradiated with a femtosecond laser, it exhibits a femtosecond-level response time, thus overcoming the slow operation of electronic logic gates and improving computing power and signal transmission capabilities. By introducing tungsten metal into both sides of the waveguide and utilizing its photorefractive effect, the all-optical logic device uses tungsten metal for optical modulation. Leveraging the ability of surface plasmons to overcome the diffraction limit, it achieves the operation and integration of all-optical logic gates at the nanoscale, further reducing the size of the all-optical logic gates and significantly improving the modulation speed, with a maximum contrast ratio of 15.95 dB. It can be applied in fields such as optical computing and integrated optical control. Attached Figure Description

[0022] Figure 1 Schematic diagram of a surface plasmon all-optical AND gate device;

[0023] Figure 2 Schematic diagram of a surface plasmon all-optical OR gate device;

[0024] Figure 3 Schematic diagram of a surface plasmon all-optical NAND gate device;

[0025] Figure 4 This is a demonstration diagram of femtosecond laser incident light.

[0026] Figure 5 This is a diagram illustrating the modulation speed.

[0027] Wherein: 1-substrate; 2-grating coupler; 3-first tungsten metal; 4-second tungsten metal; 5-slit waveguide. Detailed Implementation

[0028] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0029] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0030] The present invention will now be described in further detail with reference to the accompanying drawings:

[0031] Currently, there are two main standards for logic gates: the Institute of Electrical and Electronics Engineers (IEEE) standard and the International Electrotechnical Commission (IEC) standard. According to these two standards, there are seven basic logic gates: AND, OR, NOT, NAND, NOR, XOR, and XNOR. This invention studies all-optical logic gates based on surface plasmon resonance (SPR). It applies the principles and characteristics of SPR and the optical properties of tungsten metal to design all-optical logic gates with different structures. This invention uses the finite-difference time-domain method as the basic analytical method and the fundamental principles of SPR as theoretical support. It analyzes the performance of the designed logic gates by simulating the transmission characteristics of SPR in different logic gate structures. This invention designs and analyzes all-optical AND, all-optical OR, and all-optical NAND gates respectively.

[0032] To address the challenges of establishing a low-loss, miniature all-optical logic gate model, achieving ultrafast and highly stable micro / nano neural network information processing capabilities, and expanding the application of all-optical logic devices in photonic computing and optical communication, a logic gate structure model containing normally open signals and control signals is proposed.

[0033] The present invention discloses a surface plasmon all-optical logic device, comprising: a substrate 1; grating couplers 2 are respectively disposed at both ends of the substrate 1, a slit waveguide 5 is disposed between the grating couplers 2 on the substrate 1, and a first tungsten metal 3 and a second tungsten metal 4 for modulating light are also disposed at the slit waveguide 5 on the substrate 1, the first tungsten metal 3 and the second tungsten metal 4 are respectively disposed on both sides or at the ends of the slit waveguide 5.

[0034] As a preferred embodiment, the substrate 1 is composed of a SiO2 sheet, and silver is attached to the upper surface of the SiO2 sheet.

[0035] As a preferred embodiment, the SiO2 sheet has a length of 55~75 μm and a width of 20~100 μm.

[0036] As a preferred embodiment, the first tungsten metal 3 and the second tungsten metal 4 modulate light through the optical effect of tungsten metal.

[0037] As a preferred embodiment, when the slit waveguide 5 is a single piece, the first tungsten metal 3 and the second tungsten metal 4 are respectively disposed on both sides of the slit waveguide 5 and modulate the light to form an all-optical AND gate.

[0038] As a preferred embodiment, when there are two slit waveguides 5, the first tungsten metal 3 and the second tungsten metal 4 are respectively disposed on both sides of the two slit waveguides 5 and modulate the light to form an all-optical OR gate.

[0039] As a preferred embodiment, when there are three slit waveguides 5, the first tungsten metal 3 and the second tungsten metal 4 are respectively disposed at the ends of the two slit waveguides 5 and modulate the light to form an all-optical NOT gate.

[0040] This invention also discloses a method of using a surface plasmonic all-optical logic device, comprising:

[0041] S1: Select the appropriate all-optical logic device according to the function to be implemented;

[0042] S2: A femtosecond laser pulse is used as a control signal and is incident perpendicularly on the selected first tungsten metal 3 and second tungsten metal 4 surfaces to change their optical properties and form the function of an all-optical logic gate.

[0043] S3: The signal light oblique incidence grating coupler 2 is used to realize the function of the all-optical logic gate.

[0044] As a preferred embodiment, the femtosecond laser pulse in S2 has a wavelength of 1550nm and a pulse width of 120fs.

[0045] As a preferred embodiment, the performance of the all-optical logic gates in S2 is controlled by the extinction ratio ER, wherein...

[0046]

[0047] It is the transmittance when the output logic is "1". It is the transmittance when the output logic is "0".

[0048] All-optical AND gates optically modulate tungsten metal using two control signals. When the tungsten metal is illuminated by the control signals, its refractive index changes, thus modulating the logic gate. All-optical OR gates optically modulate tungsten metal using two control signals. When the tungsten metal is illuminated by the control signals, its refractive index changes, thus modulating the logic gate. All-optical NAND gates modulate the logic gate using the principle of coherent cancellation between two beams. When the two control signals are out of phase by (2k+1)π, the two beams coherently cancel each other out. In operation, all-optical logic devices use two femtosecond laser pulses with a wavelength of 1550nm and a pulse width of 120fs as control signals, which are incident perpendicularly on the surface of tungsten metal, altering its optical properties. When illuminated, the tungsten metal is in an excited state, providing light transmission; when not illuminated, it is in a non-excited state, providing light filtering. Normally open signal light forms surface plasmons in the air slits on the silver surface, undergoing different optical modulations as it passes through the tungsten metal, thus forming the function of an all-optical logic gate.

[0049] See Figure 1 The all-optical AND gate in this invention is constructed using a SiO2 substrate 1, a grating coupler 2, a first tungsten metal 3, a second tungsten metal 4, and a slit waveguide 5 to form a surface plasmon all-optical AND gate. Tungsten metal is introduced to both sides of the slit waveguide 5, and light is modulated through the photorefractive effect of tungsten. The SiO2 substrate 1 is composed of a SiO2 sheet with a length of 57 μm, a width of 25 μm, and a height of 1 μm. Because SiO2 has a high refractive index in air, it produces better results in photon transmission. A 300 nm thick layer of silver is attached to the surface of the SiO2 substrate 1.

[0050] Referring to Table 1, two control beams, A and B, illuminate the first tungsten metal 3 and the second tungsten metal 4, respectively, while the signal beam is obliquely incident on the grating coupler 2. An all-optical AND gate is formed by changing the switching of the control beams. The designed device is simulated and analyzed using the finite-difference time-domain method. The signal beam from a mode light source is used, with a working wavelength of 1.55 μm. The incident method is as follows... Figure 4 As shown. The performance of all-optical logic gates can be studied using the extinction ratio ER, where... , It is the transmittance when the output logic is "1". This refers to the transmittance when the output logic is "0". When the transmittance detected by the output port is less than or equal to 5%, the output result is considered as logic "0"; when the transmittance detected by the output port is greater than or equal to 10%, the output result is considered as logic "1". The control light sources are represented by IA and IB, respectively, and the signal light source is represented by PC, with the signal light source PC being normally open.

[0051] Table 1 Truth Table of All-Optical AND Gates for Surface Plasmon Polaritons

[0052]

[0053] See Figure 2 The all-optical OR gate in this invention is constructed using a SiO2 substrate 1, a grating coupler 2, a first tungsten metal 3, a second tungsten metal 4, and an MZI slit waveguide 5 to form a surface plasmon all-optical OR gate. The SiO2 substrate 1 is composed of a SiO2 sheet with a length of 63 μm, a width of 30 μm, and a height of 1 μm. Because SiO2 has a high refractive index in air, it produces better results in photon transmission. A 300 nm thick layer of silver is attached to the surface of the SiO2 substrate 1.

[0054] Referring to Table 2, two control lights, A and B, illuminate the first tungsten metal 3 and the second tungsten metal 4, respectively, while the signal light is obliquely incident on the grating coupler 2. An all-optical logic OR gate is formed by changing the switching of the control lights. The designed device is simulated and analyzed using the finite-difference time-domain method. A modal light source is used for incident illumination, with a working wavelength of 1.55 μm. The incident method is as follows... Figure 4 As shown. The performance of all-optical logic gates can be studied using the extinction ratio ER, where... , It is the transmittance when the output logic is "1". This refers to the transmittance when the output logic is "0". When the transmittance detected by the output port is less than or equal to 5%, the output result is considered as logic "0"; when the transmittance detected by the output port is greater than or equal to 10%, the output result is considered as logic "1". The control light sources are represented by IA and IB, respectively, and the signal light source is represented by PC, with the signal light source PC being normally open.

[0055] Table 2 Truth Table of All-Optical OR Gates for Surface Plasmons

[0056]

[0057] See Figure 3 The all-optical NAND gate in this invention is constructed using a SiO2 substrate 1, a grating coupler 2, and a slit waveguide 5 to form a surface plasmon all-optical NAND gate. The SiO2 substrate 1 is composed of a SiO2 sheet with a length of 74 μm, a width of 90 μm, and a height of 1 μm. Because SiO2 has a high refractive index in air, it can produce better results in photon transmission. A 300 nm thick layer of silver is attached to the surface of the SiO2 substrate 1.

[0058] Referring to Table 3, the two control beams A and B are obliquely incident on grating couplers 2 and 4, respectively, and the signal beam is obliquely incident on grating coupler 3. By changing the phase of control beam A to (2k+1)π, beams A and B coherently cancel each other out, thus achieving the function of an all-optical logic NAND gate.

[0059] Table 3 Truth Table of All-Optical AND-NOT Gates for Surface Plasmon Polaritons

[0060]

[0061] This application utilizes the photorefractive effect of tungsten metal. When femtosecond lasers irradiate tungsten, it achieves a femtosecond-level response time, thus overcoming the slow operation of electronic logic gates and improving computing power and signal transmission capabilities. By introducing tungsten metal into both sides of the waveguide and utilizing its photorefractive effect, the all-optical logic device achieves optical modulation through tungsten metal, significantly increasing the modulation speed. Its modulation speed is as follows: Figure 5 As shown, by utilizing the property that surface plasmons can overcome the diffraction limit, the operation and integration of all-optical logic gates can be realized at the nanoscale, further reducing the size of all-optical logic gates. This can be applied in fields such as optical computing and integrated optical control.

[0062] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A plasmonic all-optical logic device, characterized in that, Comprising: A substrate (1); grating couplers (2) are respectively arranged at both ends on the substrate (1), a slit waveguide (5) is arranged between the grating couplers (2) on the substrate (1), and a first tungsten metal (3) and a second tungsten metal (4) for modulating light are also arranged at the position of the slit waveguide (5) on the substrate (1), and the first tungsten metal (3) and the second tungsten metal (4) are respectively arranged on both sides or the ends of the slit waveguide (5); the substrate (1) is composed of a SiO2 sheet, and silver is attached to the upper surface of the SiO2 sheet.

2. The plasmonic all-optical logic device according to claim 1, wherein, The SiO2 sheet has a length of 55 - 75 um and a width of 20 - 100 um.

3. The plasmonic all-optical logic device according to claim 1, wherein, The first tungsten metal (3) and the second tungsten metal (4) modulate light through the photorefractive effect of tungsten metal.

4. The plasmonic all-optical logic device according to claim 1, wherein, When the slit waveguide (5) is one, the slit waveguide (5) is arranged in a "one" shape on the substrate (1), between the grating couplers (2), and the first tungsten metal (3) and the second tungsten metal (4) are respectively arranged on both sides of the slit waveguide (5) and modulate light, forming an all-optical AND gate.

5. The plasmonic all-optical logic device according to claim 1, wherein, When the slit waveguide (5) is two, the two slit waveguides (5) are merged at both ends and separated in the middle and arranged in a "square" shape on the substrate (1), between the grating couplers (2), and the first tungsten metal (3) and the second tungsten metal (4) are respectively arranged on the two slit waveguides (5), parallel to each other and modulate light, forming an all-optical OR gate.

6. The plasmonic all-optical logic device according to claim 1, wherein, When the slit waveguide (5) is three, the three slit waveguides (5) are separated from each other at one end and merged at the other end and arranged on the substrate (1), and grating couplers (2) are respectively arranged at the four ends formed by the three slit waveguides (5) and modulate light, forming an all-optical NOT gate.

7. The method of using a plasmonic all-optical logic device according to any one of claims 1-6, wherein, Comprising: S1: Select the corresponding all-optical logic device according to the function to be realized; S2: Use a femtosecond laser pulse as a control signal, vertically incident on the surfaces of the selected first tungsten metal (3) and second tungsten metal (4) to change their optical properties; S3: Use the signal light to obliquely incident on the grating coupler (2) to realize the function of the all-optical logic gate.

8. The method of claim 7, wherein the surface plasmonic all-optical logic device is a plasmonic NOT gate. In S2, the wavelength of the femtosecond laser pulse is 1550 nm and the pulse width is 120 fs.

9. The method of claim 7, wherein the surface plasmonic all-optical logic device is a plasmonic NOT gate. In S2, the performance of the all-optical logic gate is controlled by the extinction ratio ER, where, It is the transmittance when the output logic is "1". It is the transmittance when the output logic is "0".

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