Optical Full Adder Research Articles

Implementation of photonic crystal based optical full adder using ring resonators

In this paper, the implementation of an all-optical full adder based on a two-dimensional photonic crystal is proposed. The proposed structure consists of hexagonal lattice of silicon rods embedded in air substrate. To design the proposed optical full adder, three nonlinear ring resonators, some linear waveguides, and some point defects are used. The switching mechanism of the ring resonators is based on nonlinear Kerr effect. The performance of the proposed structure has been analyzed and investigated by using plane wave expansion (PWE) and finite difference time domain (FDTD) methods. The minimum contrast ratio of the structure is 17.02 dB. The response time of the structure is 0.724 ps and can operate at a bit rate of 1.381 Tb/s. The proposed structure is simple, compact, and offers high contrast ratio, fast response time along with high bit rate and therefore can be a promising candidate for high speed data processing, computing, networking, and optical integrated circuits.

Ultra-compact optical full-adder based on directed logic and microring resonators.

Photonic integrated circuits with compact design have opened possibilities for the development of optical computing systems; however, the overuse of photonic components in optical designs has slowed the progress of dense integration. In this paper, we propose an ultra-compact optical full-adder based on directed logic and microring resonators. To the best of our knowledge, the proposed structure requires fewer optical components than any other current designs, resulting in a significantly reduced footprint 59.2µm×29.2µm. Also, the proposed structure exhibits a maximum delay time of approximately 10ps, implying a minimum date rate of 100GHz. Simulation results by finite-difference time-domain (FDTD) demonstrate the effectiveness and feasibility of the proposed optical full-adder.

Design, simulation, and optimization of optical full-adder based on Mach–Zehnder interference

The rapid pace of data growth and the need for its transmission have increased the need for optical communications. For this reason, the growing need for optical telecommunications as one of the sub-sectors of telecommunications is increasing. Therefore, many studies and research have been done for the construction, improvement, and optimization of telecommunication devices. In optical telecommunications, the volume of data is high and the speed of information transfer is much higher than in other types of telecommunications. In this paper, the optical full-adder structure based on Mach–Zehnder interference (MZI) is designed and optimized. The components of the structure including waveguides, modal expansion, and the principles of mode Coupling, in waveguides, are introduced and studied. Finally, with the help of Opti-BPM software is designed, simulated, and optimized. This tool is usually designed and implemented using Mach–Zehnder interferometers. MZI are designed and fabricated using the optoelectric properties of lithium material, whose refractive index changes with the application of voltage. All designed optical full-adder had a lower MZI number than previous works, each MZI had smaller dimensions and its output intensity for all modes 1 is equal. The footprint of the proposed device is 172000μm×500μm, which is better than all previous full-adder devices.

A Novel Design of Octal-Valued Logic Full Adder Using Light Color State Model

Due to the demand of high computational speed for processing big data that requires complex data manipulations in a timely manner, the need for extending classical logic to construct new multi-valued optical models becomes a challenging and promising research area. This paper establishes a novel octal-valued logic design model with new optical gates construction based on the hypothesis of Light Color State Model to provide an efficient solution to the limitations of computational processing inherent in the electronics computing. We provide new mathematical definitions for both of the binary OR function and the PLUS operation in multi valued logic that is used as the basis of novel construction for the optical full adder model. Four case studies were used to assure the validity of the proposed adder. These cases proved that the proposed optical 8-valued logic models provide significantly more information to be packed within a single bit and therefore the abilities of data representation and processing is increased.

Investigation of light behavior of all optical full adders in two‐dimensional photonic crystals

AbstractIn this article, an optical full adder is investigated in terms of light flow inside the two‐dimensional (2‐D) crystal lattice waveguide structures. The phenomenon such as resonance, splitter, and combiner based on the principle of constructive and destructive interference is used in the modeling of all optical full adders. Also, defects are introduced in the junction of the waveguide structures to pass/stop light wave inside the waveguide structure. The designed full adder structure in 2‐D photonic crystals (PhCs) occupies an area of 382.91 μm2 and maximum light confinement at the Sum and Cout output ports are 0.52 and 0.6 arbitrary unit (a.u.), respectively. The response time of the full adder structure is about 0.25 ps and the maximum contrast ratio achieved at the Sum is 7.16 dB and Cout is 5.74 dB. RSoft FullWAVE simulation tool is used to perform a full‐vector simulation of photonic structures.

A proposal for an all optical full adder using nonlinear photonic crystal ring resonators

Optical full adders are one of the main building blocks required for realizing optical computers and Arithmetic Logic Units. In this paper we aim to design and propose an all optical full adder using nonlinear photonic crystal ring resonators. First of all an optical limiter was proposed using two nonlinear resonant rings. Then the final structure was created using the optical limiter. The maximum delay time for the proposed structure obtained to be 2 ps. As mentioned reducing the variation between the minimum and maximum optical power level for the logic 1 state at the output ports are the most important feature of the proposed structure.

Application of nonlinear photonic crystal ring resonators in realizing all optical OR/NOT/AND gates

Arithmetic logic unit (ALU) is the core of any digital processing systems. For creating an all optical ALU one needs basic logic gates such as optical NOT, OR and AND gates along with an optical full adder and optical multiplexer. In this paper we aim to design and propose these three basic logic gates using nonlinear photonic crystal ring resonators. The simulations will be done using plane wave expansion and finite difference time domain methods. The proposed structures work based on controlling the optical behavior of the nonlinear resonators using optical power. The simulation results show that the switching threshold for this resonant ring is about 15 mW/μm2. Reduced delay times and switching optical power are the main advantages of the proposed structures. Also by adding two resonant rings in input ports we reduced the cross reflection between the input ports.

Design and simulation of an all optical full-adder based on photonic crystals

In this paper, we have designed and investigated a new all optical full-adder based on two-dimensional photonic crystal, using interaction between incident signals in optical waveguides. The designed structure is simple and it is only consisted of 15 × 22 dielectric rods with a radius of 109 nm in a square cell and lattice constant of 409 nm, which incorporates of five optical waveguides. Two types of defects have been used to control the light behavior. The surface of the proposed structure is equal to 72 μm2, hence it is very compact. The operating wavelength of the proposed device is 1550 nm which is appropriate for telecommunication systems. The average delay time of the device is less than 2 ps, which indicates a data rate of more than 0.5 THz. This structure has a smaller size, faster response, and larger separation, between logic level 0 and 1, compared to two previously reported structures (the average constant ratio of device is 11 dB).

Design and analysis of an optical full-adder based on nonlinear photonic crystal ring resonators

In this paper, first we have used a photonic crystal ring resonator in a two-dimensional structure composed of GaAs rods for designing a channel drop filter (CDF). Then the CDF is used to design a 1-bit full-adder. The structure has two nonlinear ring resonators which are coupled to eight waveguides. The nonlinear ring resonators have Kerr-type nonlinearity which causes the resonant mode of photonic crystal resonators to depend on intensity of input power launched into the structure. The proposed structure has three input and two output ports which are dubbed “A”, “B” and “C” as input and “Sum” and “Carry” as output. The maximum delay time of the structure is about 3 ps. The structure has been simulated and analyzed using finite difference time domain (FDTD) and plane wave expansion (PWE) methods. The main advantages of the proposed structure are compactness, reduction of the delay time, reduction of the optical power intensity required at input ports and reduction of the backward reflection toward the input ports.

An ultra-compact all optical full adder based on nonlinear photonic crystal resonant cavities

In this paper we are going to propose and design an all optical full adder based on photonic crystal. For realizing the proposed structure we will use four nonlinear resonant cavities inside a two dimensional photonic crystal. Nonlinear resonant cavities will be created by replacing the ordinary rods via defect rod made of nonlinear material such as doped glass. The simulation results show that the worst cases for logics 0 (the maximum normalized power in OFF state) and 1 (the minimum normalized power in ON state) are 3% and 53% for SUM port and they are 10% and 100% for CARRY port respectively. Also the maximum delay time for the proposed device is about 8 ps.

Frequency encoded data based optical full adder using reversible Toffoli gates

In WDM communication based networks the processors have to deal with large number of data. It is seen that the data loss becomes significant when the conventional logic gates have been used as the building block of the processors. The reversible logic gates already have established its utility due to its low power consumption and less hardware complexity. In case of reversible logic gate, inputs are directly mapped to outputs after performing some logic functions. As the inputs of the reversible gate can be uniquely recovered from the outputs, power loss is ideally zero. Toffoli gate, invented by Tommaso Toffoli is one of the most common universal reversible logic gates. It is a three-input-three-output reversible logic gate. In this article, authors have proposed a new technique of designing optical Toffoli gate, and subsequently propose a method of developing an optical full adder with the help of Toffoli gates. For this purpose the authors have deployed the polarization switching characteristic of semiconductor optical amplifier (SOA). The authors have exploited frequency encoded data due to the inherent identity. The proposed optical frequency encoded full adder will be a key component of an optical reversible Arithmetic Logic Unit (ALU), or any other reversible optical computing. Simulation results of the Toffoli gate based on theoretical model PSW show the feasibility of the of the proposed scheme.

ALL OPTICAL IMPLEMENTATION OF HIGH SPEED AND LOW POWER REVERSIBLE FULL ADDER USING SEMICONDUCTOR OPTICAL AMPLIFIER BASED MACH-ZEHNDER INTERFEROMETER

In the recent years reversible logic design has promising applications in low power computing, optical computing, quantum computing. VLSI design mainly concentrates on low power logic circuit design. In the present scenario researchers have made implementations of reversible logic gates in optical domain for its low energy consumption and high speed. This study is all about designing a reversible Full adder using combination of all optical Toffoli and all optical TNOR and to compare it with the Full adder designed using all optical Toffoli gate in terms of optical cost. All optical TNOR gate can work as a replacement of existing NAND based All optical Toffoli Gate (TG). The gates are designed using Mach-Zehnder Interferometer (MZI) based optical switch. The proposed system is developed with the basic of reversibility to design all optical full Adder implemented with CMOS transistors. The design is efficient in terms of both architecture and in power consumption.

Realization of All Optical Full Adder by Utilizing DM Soliton Pulses

Realization of All Optical Full Adder by Utilizing DM Soliton Pulses

All-Optical Incrementer/Decrementer with the Help of Semiconductor Optical Amplifier-Assisted Sagnac Switch

In this article, an all-optical adder based incrementer/decrementer circuit is proposed and described with the help of Semiconductor Optical Amplifier (SOA)-assisted Sagnac switch. The proposed design is more efficient in terms of speed and hardware complexity. The article describes the incrementer/decrementers using a set of optical half adder and full adder. The principle and possibilities of all-optical incrementer/decrementers is explained. A theoretical model is presented and verified through numerical simulation. The new method promises both higher processing speed and accuracy. The model can be extended for studying more complex all-optical circuit of enhanced functionality in which incrementer/decrementers is the basic building block.

The azulene–rhodamine all optical full adder

The original suggestion made by Levine and co-workers to utilize the azulene-rhodamine bichromophoric system to constract full adder logic at the molecular scale is now implemented. Preliminary results are presented pertaining to a newly synthesized bicromophoric molecule based on this pair, in which, for the first time, an all optical full adder is implemented, utilizing two-photon nonlinear optical excitation and intramolecular electronic energy transfer between the two moieties.

A novel all optical molecular scale full adder

We show, that one molecule can communicate its logic output as input to another molecule. This transfer is achieved as an electronic energy transfer from a donor to an acceptor. We discuss a specific pair, the rhodamine 6G-azulene, for which there is considerable data, but the scheme is general enough to allow a wide choice of D and A pairs. We present results pertaining to a newly synthesized bichromophoric molecule based on this pair, in which a for the first time an all optical full adder is implemented, utilizing two-photon nonlinear optical excitation and intramolecular electronic energy transfer between the two moieties.

Optical guided wave arithmetic

Two novel full adder architectures are proposed that can be implemented with optical couplers using fiber optics or integrated optics. The first adder has the advantage over other proposed approaches by requiring only three different component devices: optical logical OR, op- tical logical NOT, and optical couplers. Configurations of the three com- ponents are described that are relatively simple to implement and are expected to function at greater than gigabit per second rates. The sec- ond adder requires fewer gates by using additional different gates: ana- log ADD and thresholding. Methods of implementing in fiber optics and with integrated optics are suggested including the synchronization of the lasers and methods for changing phase. The optical full adder can be used to provide high speed word addition by multiplexing independent additions. The pros and cons of fiber optics versus integrated optics for one architecture versus the other are discussed. © 1999 Society of Photo- Optical Instrumentation Engineers. (S0091-3286(99)00603-0)

Polarization-encoded optical logic operations in photorefractive media

We propose and demonstrate optical logic operations using polarization encoding and wave mixing in photorefractive crystals. In our approach two orthogonal polarization states of light beams are used to represent respective logic values of 1 and 0. All 16 two-input logic operations can be easily achieved by use of the recording and readout of photoinduced volume gratings in photorefractive crystals. An optical full adder is also proposed and demonstrated.

Optical full adder

We report construction and successful operation of a ripple carry full adder with an architecture based on symbolic substitution logic. The principal piece of hardware is a microchannel spatial light modulator. Examples of its operation are given for addition of 4-bit numbers.

Implementation of a binary optical full adder using a Venn diagram and optical phase conjugation

Conventional optical pattern logic schemes can only process two input variables at a time. We propose a new optical spatial encoding scheme that is capable of simultaneously processing multiple input variables. Based on this new scheme an optical full adder was experimentally demonstrated using a picosecond optical phase-conjugation device.