Polarization encoded all-optical quaternary R-S flip-flop using binary latch

The developments of different multi-valued logic (MVL) systems have received considerable interests in recent years all over the world. In electronics, efforts have already been made to incorporate multi-valued system in logic and arithmetic data processing. But, very little efforts have been given in realization of MVL with optics. In this paper we present novel designs of certain all-optical circuits that can be used for realizing multi-valued logic functions. Polarization encoded all-optical quaternary (4-valued) R-S flip-flop is proposed and described. Two key circuits (all-optical encoder/decoder and a binary latch) are designed first. They are used to realize quaternary flip-flop in all-optical domain. Here the different quaternary logical states are represented by different polarized state of light. Terahertz Optical Asymmetric Demultiplexer (TOAD) based interferometric switch can take an important role. Computer simulation result confirming described methods and conclusion are given in this paper.     

Polarization-encoded all-optical quaternary multiplexer and demultiplexer - A proposal

Multi-valued logic is positioned as a coming generation technology that can execute arithmetic functions faster and with less interconnect than binary logic. Furthermore, nonbinary data storage would require less physical space than binary data. The application of multi-valued digital signals can provide considerable relief of capacity constraints. In electronics many proposals have already been reported. But, here for the first time we propose an all-optical circuit for designing quaternary (four-valued) multiplexer and demultiplexer with the help of some polarization-encoded basic quaternary logic gates (quaternary min and quaternary delta literal). Nonlinear interferometer-based optical switch can take an important role here. The principles and possibilities of design of all-optical quaternary multi-valued multiplexer and demultiplexer circuits are proposed and described.     

Passive, “self-trapped family” all-optical half adder using all-optical XOR and AND gates

The paper presents an alternative novel approach to obtain all-optical logic. We show that XOR, NOT, and AND logic could be obtained by appropriately setting parameter of all-optical passive transistor. An AND gate followed by NOT gives NAND logic (building block) that, in principle can provide complete set of passive, fiber compatible “self-trapped family” all-optical logic gates (with Boolean completeness) and may find many possibilities in the area of all-optical computing. To give one example, we propose all-optical half adder.     

Designing of an all-optical scheme for single input ternary logical operations

In this paper, for the first time to our knowledge, we propose and describe a novel design of single circuit capable of generating all the possible 27 logic functions for single input ternary (3-valued) logic system in all-optical domain. Here the different logical states have been represented by different polarized state of light. Terahertz optical asymmetric demultiplexer (TOAD) based interferometric switch plays a significant role as ultra-fast all-optical switching device. Proposed all-optical circuit is numerically investigated and simulated.     

Coupled-Soliton All-Optical Logic Device with Two Parallel Tapered Waveguides

In this article, a new all-optical logic device by using the interaction of spatial solitons has been proposed. The operation of the proposed device is based on the evolution of a nonlinear guided wave propagating along two parallel tapered waveguides with a Kerr-type nonlinear medium between them. The numerical results show that this device could be potentially useful in several all-optical logic functions (AND, OR, and XOR).     

Coupled-Soliton All-Optical Logic Device with Two Parallel Tapered Waveguides

In this article, a new all-optical logic device by using the interaction of spatial solitons has been proposed. The operation of the proposed device is based on the evolution of a nonlinear guided wave propagating along two parallel tapered waveguides with a Kerr-type nonlinear medium between them. The numerical results show that this device could be potentially useful in several all-optical logic functions (AND, OR, and XOR).     

Erratum to: Multiple magnetic transitions in single crystals of Ce12Fe57.5As41and La12Fe57.5As41

Commercial computers based on electronic logic devices have brought great changes to the world. However, traditional electronic devices are suffering from numerous technical challenges in their attempts to continue to satisfy Moore's law. Alloptical logic devices, as promising successors to their electronic counterparts, have become a major focus of optics research. In this paper, we provide a review of current all-optical logic devices. The logic gates in these devices, which are described in the first part of the review, are divided into five categories based on the different principles used in their realization. Complex optical devices with various functions and reconfigurable devices are summarized in the next section. In the final part of this paper, we discuss some of the previous works on all-optical integrated chips with specific functions. This review will provide a complete technological roadmap for all-optical devices and aims to be helpful in possible future developments in this growing field.     

半导体光放大器的稳态增益饱和特性

高速全光逻辑门是实现光分组交换、光计算和未来高速大容量光传输的关键器件,近年来受到广泛的关注。半导体光放大器（SOA）因为具备体积小、工作波长范围宽、响应时间短及良好的非线性特性等优点,成为研制高速全光逻辑器件的首选。采用分段模型分析了SOA的稳态增益饱和特性,通过数值求解载流子速率方程和光传输方程对其特性进行了仿真实现。结果表明,SOA在入射光功率不同时会表现出明显的非线性;在一定范围内增加光功率,SOA增益持续增加,继续增加入射光功率,SOA逐渐进入饱和吸收状态,增益反而降低。     

基于非线性光纤环镜的40Gb/s可重构光逻辑门

提出了一种新型的基于非线性光纤环镜(NOLM)的可重构全光逻辑门实现方案。传统的基于NOLM的全光逻辑利用自相位调制效应或交叉相位调制效应,透射传输函数重构的自由度低,可实现的逻辑门种类较少。该方案在传统的结构基础上,分析了NOLM中探测光的偏振态的演化,以及输入光偏振态和环内偏振控制器对NOLM的传输特性的影响。理论分析和数值仿真结果表明在考虑NOLM中的非线性偏振旋转效应的情况下,可以更加自由地构建不同透射传输函数,从而利用单一NOLM结构,仅通过调节偏振控制器,即能够可重构地实现绝大部分基础组合逻辑。实验中,完成了两路40Gb/s的数据信号之间的"非"、"与"、"或"、"或非"、"同或"、"异或"等各种基础组合逻辑,验证了方案的可行性。     

All-optical reconfigurable logic operations with the help of terahertz optical asymmetric demultiplexer

An all-optical reconfigurable logic operation essentially constitutes a key technology for avoiding complex and speed limited optoelectronics conversions and performing various processing tasks. All-optical reconfigurable logic operations with the help of terahertz optical asymmetric demultiplexer (TOAD) is proposed and described. The paper describes the all-optical reconfigurable logic operations using a set of all-optical multiplexer and optical switches. We have tried to exploit the advantages of TOAD-based switch to design an integrated all-optical circuit which can perform the different logic operations AND, XOR, NOR and NOT. Numerical simulation confirming described methods is given in this paper.     

All optical switching in henna thin film

The optical nonlinearity in henna (Lawson (2- hydroxyl-1,4 naphthoquinone) film was utilized to demonstrate all optical switching. The nonlinear absorption of the henna film was calculated by measuring the transmission of the laser beam (λ = 488 nm) as a function of incident light intensities. The observed nonlinear absorption is attributed to a two-photon absorption process. The pump and probe technique was used to demonstrate all optical switching. The switching characteristics can be utilized to generate all-optical logic gates such as simple inverter switches (NOT) NOR, AND NAND logic functions.     

Design and analysis of an all-optical processor for modular arithmetic

We present a logical design of an all-optical processor that performs modular arithmetic. The overall design is based a set of interconnected modules that use all-optical gates to perform simple logical functions. The all-optical logic gates are based on the semiconductor optical amplifier nonlinear loop. Simulation results are presented and some practical design issues are discussed.     

Mach-Zehnder interferometer-based all-optical reversible logic gate

In recent years, reversible logic has emerged as a promising computing paradigm having application in low-power CMOS, quantum computing, nanotechnology and optical computing. Optical logic gates have the potential to work at macroscopic (light pulses carry information), or quantum (single photons carry information) levels with great efficiency. However, relatively little has been published on designing reversible logic circuits in all-optical domain. In this paper, we propose and design a novel scheme of Toffoli and Feynman gates in all-optical domain. We have described their principle of operations and used a theoretical model to assist this task, finally confirming through numerical simulations. Semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer (MZI) can play a significant role in this field of ultra-fast all-optical signal processing. The all-optical reversible circuits presented in this paper will be useful to perform different arithmetic (full adder, BCD adder) and logical (realization of Boolean function) operations in the domain of reversible logic-based information processing.     

All-optical quaternary circuits using quaternary T-gate

In multi-valued logic (radix>2), quaternary multiplexer (also known as T-gate) places a significant role for data transmission and signal processing. Four valued multiplexer transmit one data (from 4-input) to the output corresponding to the one selected input. Any four-valued logic can be implemented using T-gate. So it is called ‘universal’ element. In this paper some all-optical quaternary logical operations, quaternary half-adder, quaternary multiplier and quaternary comparator is proposed and described using only all-optical quaternary T-gate.     

All-optical reconfigurable multi-logic gates based on nonlinear polarization rotation effect in a single SOA

We demonstrate an all-optical reconfigurable logic gate based on dominant nonlinear polarization rotation accompanied with cross-gain modulation effect in a single semiconductor optical amplifier (SOA).Five logic functions,including NOT,OR,NOR,AND,and NAND,are realized using 10-Gb/s on-off keying signals with flexible wavelength tunability.The operation principle is explained in detail.By adjusting polarization controllers,multiple logic functions corresponding to different input polarization states are separately achieved using a single SOA with high flexibility.     

基于高非线性光纤中非线性偏振旋转效应的全光逻辑门研究

提出了一种新型的基于高非线性光纤(HNLF)中非线性 偏振旋转(NPR)效应的全光逻辑门实现方案. 将两路非归零码数据信号A和B以及一路直流光同时注入HNLF, 光功率变化导致的非线性双折射在两个偏振分量上引入非线性相对相移, 从而导致光信号的偏振态旋转. 在HNLF输出端, 通过波分解复用器和偏振分束器同时滤出数据信号和直流光的正交偏振态, 从而同时实现多种基础组合逻辑, 并可以在同一段HNLF中实现较为复杂的半加器、半减器逻辑功能. 理论分析了信号光在HNLF中的偏振态演化, 以及利用HNLF中的NPR效应同时实现多种全光逻辑门的原理. 并在实验中得到了10 Gbit/s全光信号"与”、"非”、"或”、"同或”、"异或”、"A· B”、"A·B”、半加器、半减器等逻辑功能, 验证了方案的可行性.     

All-Optical Logic Device Using Bent Nonlinear Tapered Y-Junction Waveguide Structure

We propose an all-optical logic device made of a bent tapered Y-junction waveguide with a Kerr-type nonlinear interface. It could provide an AND gate, OR gate, and exclusive-OR (XOR) gate. We could obtain different transmission results by adjusting the bending angle. The numerical simulation results show that the device functions as AND, OR, and XOR gates.     

All-optical logic gates and a half-adder based on lithium niobate photonic crystal micro-cavities

All-optical logic gates including AND, XOR, and NOT gates, as well as a half-adder, are realized based on twodimensional lithium niobate photonic crystal(PhC) circuits with Ph C micro-cavities. The proposed all-optical devices have an extinction ratio as high as 23 dB due to the effective all-optical switch function induced by twomissing-hole micro-cavities. These proposed devices can have potential implementation of complex integrated optical functionalities including all-optical computing in a lithium niobate slab or thin film.     

All-Optical Logic Device Using Bent Nonlinear Tapered Y-Junction Waveguide Structure

We propose an all-optical logic device made of a bent tapered Y-junction waveguide with a Kerr-type nonlinear interface. It could provide an AND gate, OR gate, and exclusive-OR (XOR) gate. We could obtain different transmission results by adjusting the bending angle. The numerical simulation results show that the device functions as AND, OR, and XOR gates.     

基于掺锡As2S8条波导的全光逻辑门研究

实验研究了掺锡As2S8条波导的光阻断效应,提出一种新型的基于掺锡As2S8波导的全光逻辑门方案,并试制了掺锡As2S8条波导全光逻辑门,实验结果显示该逻辑门具有良好的波形特性,表明该材料适合做全光逻辑门,具有一定的应用潜力.