All-optical Logic Gates Research Articles

Performance analysis of all-optical NAND, NOR, and XNOR logic gates using photonic crystal waveguide for optical computing applications

All-optical photonic integrated devices have gained great attention in the field of optical computing and large-scale integration. All-optical logic gates are useful for optical signal processing and optical communication network. The flexible devices presented here satisfy the functionality of NAND (NOT-AND), NOR (NOT-OR), and XNOR (exclusive NOR) logic gates using only one structure with proper changes in the phase of an applied light signal. The design of all-optical logic gates is implemented with photonic crystal waveguides using square lattice silicon rods. The performance of the structure is simulated, verified, and analyzed by the finite-difference time-domain method, with the principle of interference effect at a wavelength of 1550 nm. The contrast ratio (CR) of NAND, NOR, and XNOR logic gates is 17.59, 14.3, and 10.52 dB, respectively, with an optimized size of 7.2 μm × 5.4 μm.

Simulation of reconfigurable double-input optical gates based on a microring flower-like structure. part I. basic gates.

In this paper, a simulation and general analysis of nonlinear microring resonators (MRRs) as all-optical switches are discussed in a flower-like structure. These MRRs are modulated through an optical pump beam, which receives temporal shift of MRRs' resonance wavelengths. These shifts are a result of the refractive index changing due to carrier injection. A green laser is used as the optical pump to shift the resonant wavelength of each MRR. This proposed structure can operate as all-optical logic gates. Of those innovations are reconfigurable structure to achieve various gates, integrating capability, and a high extinction ratio between zero and one logical levels. This configuration would be useful to design optical integrated circuits.

Creation of a fast optical Toffoli gate based on photonic crystal nonlinear ring resonators

All-optical reversible logic gates can play crucial roles in the next generation of all-optical computing systems. In this paper, we will propose and design an all-optical Toffoli gate using photonic crystal-based nonlinear ring resonators. The proposed structure has three input and three output ports. There is a one-by-one mapping between the input and output ports; therefore, the proposed structure is a reversible gate with the maximum time delay about 2 ps and suitable for optical communication applications.

Design of Plasmonic NOT Logic Gate Based on Insulator – Metal – Insulator (IMI) waveguides

In this work, all-optical plasmonic NOT logic gate was proposed using Insulator-Metal-Insulator (IMI) plasmonic waveguides Technology. The proposed all-optical NOT gate is simulated and realized using COMSOL Multiphysics 5.3a software. Recently, plasmonic technology has attracted high attention due to its wide applications in all-optical signal processing. Due to its highly localization to metallic surfaces, surface plasmon (SP) may have huge applications in sub wavelength to guide the optical signal in the waveguides which results in overcoming the diffraction limit problem in conventional optics. The proposed IMI structure is consist of a dielectric waveguides plus metallic claddings, which guide the incident light strongly in the insulator region. Our design consists of symmetric nano-rings structures with two straight waveguides which based on IMI structure. The operation of all-optical NOT gate is realized by employing the constructive and destructive interface between the straight waveguides and the nano-rings structure waveguides. There are three ports in the proposed design, input, control and output ports. The activation of control port is always ON. By changing the structure dimensions, the materials, the phase of the applied optical signal to the input and control ports, the optical transmission at the output port is changed. In our proposed structure, the insulator dielectric material is glass and the metal material is silver. The calculated contrast ratio between (ON and OFF) output states is 3.16 (dB).

Liquid phase exfoliated boron nanosheets for all-optical modulation and logic gates

Boron nanosheets possess unique photoelectric properties, including photosensitivity, photoresponse, and optical nonlinearity. In this article, we show the interaction between light and boron nanosheets in which concentric rings formed in the far field, which attributed to the strong Kerr nonlinearity of boron nanosheets. Furthermore, the distortion, regulation and relationship between the Kerr nonlinearity and effective mass or carrier mobility of the diffraction rings of boron nanosheets have been investigated. Our work shows that the spatial self-phase modulation effect of boron nanosheets is indeed caused by nonlocal electronic coherence. In addition, we have implemented all-light modulation and all-light logic gates based on the prepared boron nanosheets. We believe that our results will provide a powerful demonstration of nonlinear photonic devices based on boron nanosheets and a reference for photonic devices based on two-dimensional materials.

All-Optical Switching and Multiple Logic Gates Based on Hybrid Square–Rectangular Laser

All-optical switching and multiple logic gates are experimentally demonstrated using AlGaInAs/InP hybrid square-rectangular lasers. Controllable bistability induced by saturable absorption in the square microcavity is achieved around the threshold with the square cavity in an open circuit state. Based on the bistability, all-optical switching operation is realized by injecting set/reset optical signals with the wavelengths around the lasing mode of 1529.9 nm and another high-Q mode at 1560 nm. Furthermore, mode competitions between three resonant modes around 1541 nm with an interval of 1.2 nm are used to realize all-optical multiple logic gates of NOT, NOR, and NAND functions under low-power optical pulses, with injecting currents to the square and rectangular sections. The static extinction ratio of 34, 40 and 24 dB are obtained for NOT, NOR, and NAND gates, respectively, and the dynamic extinction ratio over 10 dB of NOT function at 15 Gb/s, NOR and NAND functions at 2 Gb/s are demonstrated. With the merits of multifunctional operations, large optical injection wavelength tolerant ranges, low power consumption, small footprint and suitability for on-chip integration, the device offers a potential solution for all-optical signal processing in photonic integration circuits.

All-optical logic gate based on manipulation of surface polaritons solitons via external gradient magnetic fields

We theoretically study the magneto-optical manipulation of surface polaritons (SPs) in the negative index metamaterial--dielectric interface waveguide system. We analyze the linear and nonlinear propagation properties of the system when a weak gradient magnetic field is applied. A lossless superluminal SPs soliton is obtained via active Raman gain. We show that the SPs soliton will deflect in the weak gradient magnetic field (Stern-Gerlach-like effect); thus, the trajectory of SPs can be controlled by the gradient magnetic field, and dynamic control of SPs can also be realized by using a time-dependent gradient magnetic field. In addition, a ``XNOR''-like logic gate is realized based on the trajectory control of SPs with external magnetic field and the interaction of the SPs soliton. This paper has certain theoretical significance for nanoscale optical information processing.

Optimization of an All-Optical Photonic Crystal NOT Logic Gate Using Switch Based on Nonlinear Kerr Effect and Ring Resonator

In this paper, the use of the Kerr effect in a two-dimensional square lattice of In0.82Ga0.18As0.40P0.60 rods in photonic crystal proposes an ultra-compact all-optical NOT logic gate. The main device operation is based on the concept of all the optical switches. In our work, the novelty lies in the design of a new simple nonlinear ring based on the combination of silicon nano-crystal "Si–Nc/In0.82Ga0.18As0.40P0.60" materials that can be used. The contrast ratio and delay time for the proposed NOT logic gate are respectively 25.52 dB and 0.66 ps. The structure size is equal to 168 μm2. Designed logic gates are characterized by low energy consumption, high-speed response, compactness and easy integration. All simulations are based on Non-Linear-Finite Difference Time Domain (NL-FDTD) and Plane Wave Expansion (PWE) numerical methods.

All-Optical Logic Gate Operating with Single Input and Output Wavelength

All-Optical Logic Gate Operating with Single Input and Output Wavelength

Vortex Beam Encoded All-Optical Logic Gates Based on Nano-Ring Plasmonic Antennas.

Vortex beam encoded all-optical logic gates are suggested to be very important in future information processing. However, within current logic devices, only a few are encoded by using vortex beams and, in these devices, some space optical elements with big footprints (mirror, dove prism and pentaprism) are indispensable components, which is not conducive to device integration. In this paper, an integrated vortex beam encoded all-optical logic gate based on a nano-ring plasmonic antenna is proposed. In our scheme, by defining the two circular polarization states of the input vortex beams as the input logic states and the normalized intensity of the plasmonic field at the center of the nano-ring as the output logic states, OR and AND (NOR and NAND) logic gates are realized when two 1st (1st) order vortex beams are chosen as the two input signals; and a NOT logic gate is obtained when one 1st order vortex beam is chosen as the input signal. In addition, by defining the two linear polarization states (x and y polarization) of the input vortex beams as the two input logic states, an XNOR logic gate is realized when two 1st order vortex beams are chosen as the two input signals.

Evolution of Adder and Subtractor Circuit Using Si3N4 Microring Resonator

Abstract All-optical processor capable of processing optical bits has been a long-standing goal of photonics. In this paper, we report the results obtained by numerical simulations regarding the designing of an all-optical combinational circuit of an adder and subtractor circuits based on Si3N4 microring resonators. The designs of combinational circuit like adders and subtractor based on the use of all-optical basic logic gates are discussed while presenting the numerically simulated results. Extinction ratios of 5.2 dB, 3.5 dB and 2.7 dB are obtained for the half adder, full adder and half subtractor, respectively.

(2 + 1) dimensional all-optical logical gates based on soliton interaction in bulk nonlocal nonlinear media

We propose the (2 + 1) dimensional all-optical logical gates based on the interaction between two components of vector solitons in nonlocal nonlinear media. The input logical states are controlled by tilting the input beams or not, and the output logical states are decided by integrated power on the photodetector. We design these logical gates in a theoretical model of liquid crystal E7 with only two input beams that are tilted in 2 dimensions, and this model is suitable to other nonlocal nonlinear media. With the degrees of nonlocality and the locations of two input beams properly preset, we achieve the logical AND, NAND, OR, NOR, XOR and NXOR gates. Expecting the logical OR gate, the logical gates are based on the attractive interaction.

A design procedure for fan-out improvement in all-optical photonic crystal logic design

In this paper, a general method is proposed to improve the fan-out parameter for all-optical logic gates and functions. Two different types of devices are designed to increase the fan-out of a logic operation and its inverted logic. Nonlinear cavities are used to design driving units. Silicon nanocrystal is used as the nonlinear material to create the required frequency shift for different values of input power. Plane wave expansion and finite difference time domain methods are used to simulate and analyze the proposed structures. The propagation delay of the proposed structure is less than 1.5 ps and the maximum required power for fan-out of three is 15 W.

Design and Modeling of Polarization-Conversion Based all-Optical Basic Logic Gates in a Single Silicon Ring Resonator

The demonstration of all-optical basic logic gates using single silicon micro-ring resonator is presented in the paper. Based on the nature of the pump signal rather than its intensity, the polarization-conversion in ring resonator occurs with the response time of 0.2 ps. To validate the proposed model, the finite-difference time domain (FDTD) and Matlab simulation results are included in the report. The Q-factor and operational speed are also calculated to justify its utility. The ring parameters are optimized through numerical simulation to obtain the conversion of polarization in the ring resonator. The nature of the pump and source signal is responsible to obtain polarization conversion based all-optical switch and all-optical logic gates in the ring resonator. The design in this paper is simple and stable.

A novel structure for realization of an all-optical, one-bit half-adder based on 2D photonic crystals

In this paper, a new structure for realizing a one-bit half-adder is proposed based on 2D photonic crystals. The proposed structure consists of 25 × 20 hexagonal lattice silicon rods in an ambient of air. The main advantages of this structure are a proper distinct space between “0” and “1” logical states of outputs, and smooth and stable outputs for a long time. These advantages are found to eliminate the error in identification of logical states (i.e., 0 and 1) at outputs. Working at a 1550-nm wavelength band (the most commonly used wavelength in optical communication known as third window), the simplicity of its structure and also integrable size has made this structure very efficacious for being realized as an all-optical logic gate.

All-optical logic gate NAND using semiconductor optical amplifiers with simulation

Hybrid encoding technique for the representation of the binary states of information, four-wave mixing in semiconductor optical amplifier (SOA) as frequency generator and cross-polarization rotation effect in semiconductor optical amplifier as a frequency converter are used to design all-optical universal logic gate NAND. The devices can perform ultrafast operation and easily integrable. The simulated results of the proposed logic gate ensure feasibility of the proposals.

Design of all-optical universal logic gates using mode-conversion in single silicon microring resonator

All-optical universal logic gates are theoretically investigated and demonstrated in a single silicon microring resonator due to mode conversion. Mode conversion takes place at the switching speed of 0.2 ps and at ultrahigh quality factor (Q-factor) and requires low power. Simulated results obtained from the finite-difference-time-domain method verified our proposed model. The Q-factor for NOT, NAND, and NOR logic gates is noted as high as around 1500, 1500, and 2400, respectively. The design is simple and silicon-on-insulator compatible.

Shape Engineering of InP Nanostructures by Selective Area Epitaxy.

Greater demand for III-V nanostructures with more sophisticated geometries other than nanowires is expected because of the recent intensive investigation of nanowire networks that show great potential in all-optical logic gates, nanoelectronics, and quantum computing. Here, we demonstrate highly uniform arrays of InP nanostructures with tunable shapes, such as membrane-, prism-, and ring-like shapes, which can be simultaneously grown by selective area epitaxy. Our in-depth investigation of shape evolution confirms that the shape is essentially determined by pattern confinement and the minimization of total surface energy. After growth optimization, all of the different InP nanostructures grown under the same growth conditions show perfect wurtzite structure regardless of the geometry and strong and homogeneous photon emission. This work expands the research field in terms of producing nanostructures with the desired shapes beyond the limits of nanowires to satisfy various requirements for nanoelectronics, optoelectronics, and quantum device applications.

All-optical logic gates based on unidirectional surface plasmon polaritons

Optical logic gates are important elements in optical computing and optical circuits. In this study, all-optical logic gates, including OR, XOR, XNOR, NAND, and NOT gates, are obtained in a composite structure composed of gyroelectric material and metal based on the interference and absorption of surface waves. In the composite structure, a Y-shaped channel through which surface plasmon polaritons propagate unidirectionally is formed. Through the ingenious one-way surface plasmon polaritons, backscattering and side-scattering generated by the composite structure and influencing the surrounding devices are prohibited effectively. The precisely controlled optical phase difference ensures the realization of five different logic gates with high contrast ratios. The maximum contrast ratios for XOR, XNOR, NAND, and NOT gates are 31.64dB, 43.47dB, 31.47dB, and 43.47dB, respectively. The output logic states "1"or "0" obtained by different logic inputs have nearly the same light intensity. Our research results provide the possibility for constructing all-optical integrated logic devices.

All-optical or logic gate based on a photonic crystal fiber Michelson interferometer operating with pulse-position modulation

We present a numerical investigation of the study of the Michelson interferometer by exploring the potential of such a device to act as an all-optical logic gate when excited with ultrashort pulses of 100 fs. The input pulse is controlled by a pulse-position modulation (PPM) modulator, which has the role of controlling the value and direction of the temporal displacement from the variation of the PPM modulating factor. We present the study on the signal-to-noise ratio (SNR), which served as the basis for constructing a merit figure of the studied logic gates in order to verify their performance. We considered pulse propagation under the influence of dispersive effects, as well as the nonlinear effects in the propagation regime with no loss for the input pulses. It was possible to implement the OR logic operation in at least one interval of the modulation adjustment parameter in each of the distinct pumping power regimes, thus obtaining a total of nine intervals of OR logic gate. The situation with the best SNR = 29.36 dB, for the suggested logic gate operation, was found at the power of 150 kW with the modulation adjustment parameter e = 43 fs. Numerical studies were done from the coupled–coupled equations solved using the fourth-order Runge–Kutta method. The implementation of fully optical logic gates tends to revolutionize digital systems in the field of data storage, such as optical memory, “replacement” of electronic circuits among other applications.