An all-optical comparison scheme between two multi-bit data with optical nonlinear material

Over the last few decades, several all-optical circuits have been proposed to meet the need of high-speed data processing. In some information processing architectures, the role of various analog and digital data comparisons is very important. In this letter, we proposed a multi-bit data comparison scheme. The scheme is based on the switching property of optical nonlinear material. Ultrafast operational speed larger than gigahertz can be expected from this all-optical scheme.OCIS codes: 190.0190, 200.0200, 200.1130, 200.3760.     

An all-optical parallel scheme for the exclusive-or operation

In this letter, we propose an all-optical parallel scheme for the exclusive-or (XOR) logic processing, in which the bright and dark pixels of an image source are adopted to represent the binary data. Two orthogonally polarized coherent light beams are overlapped using a 50/50 beam splitter, and are then checked using a polarization analyzer. The distribution of light intensity of final output image is the result of the XOR logic operation on the input pixels.     

Image transfer by modulation of short light pulses

This paper shows that the Fourier-processing based modulation of short laser pulses can be successfully used for all-optical image transfer. The system under consideration consists of a transmitter, where the transferred image modulates the frequency profile of a carrier pulse, and a receiver, where after the reverse processing an original image is restored. The main limitations are discussed and the information capacity of a single pulse is obtained. The results from preliminary experiments using a CPM-ring dye laser as a source of carrier pulses are presented.     

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 conversion scheme: Binary to quaternary and quaternary to binary number

To achieve the inherent parallelism in optics a suitable number system and efficient encoding/decoding scheme for handling the data are very much essential. Binary number is accepted as the best representing number system in almost all types of existing electronic computers. But, binary number (0 and 1) is insufficient in respect to the demand of the coming generation. Multi-valued logic (with radix >2) can be viewed as an alternative approach to solve many problems in transmission, storage and processing of large amount of information in digital signal processing. Here, in this paper all-optical scheme for the conversion of binary to quaternary number and vice versa have been proposed and described. Simulation has also been done. In this all-optical scheme the numbers are represented by different discrete polarized state of light.     

Terahertz optical asymmetric demultiplexer based tree-net architecture for all-optical conversion scheme from binary to its other 2n radix based form

To exploit the parallelism of optics in data processing,a suitable number system and an efficient encoding/decoding scheme for handling the data are very essential.In the field of optical computing and parallel information processing,several number systems like binary,quaternary,octal,hexadecimal,etc.have been used for different arithmetic and algebraic operations.Here,we have proposed an all-optical conversion scheme from its binary to its other 2n radix based form with the help of terahertz optical asymmetric demultiplexer (TOAD) based tree-net architecture.     

An all-optical integrated system for implementing arithmetic operation in 2’s complement method with the active participation of non-linear material based switches

Optics is regarded undoubtedly a potential and successful candidate in information and data processing because of its inherent parallelism. In last few decades several all-optical data processors, algebraic processors, arithmetic processors are proposed. Here in this communication the authors propose a completely new scheme for implementing binary data arithmetic in 2’s Complement method which is the most advantageous among all other established subtraction methods. To implement it we use non-linear material massively.     

All-Optical Multifunctional Logic Gates for Image Information Using Photorefractive Two-Wave Mixing

In this paper, we propose all-optical multifunctional logic gates for image information using photorefractive (PR) two-wave mixing. The optical setup is simply configured compared with the other all-optical logic gates for image information. The XOR-, OR-, and AND-operation are all-optically performed in the same optical setup through the transitional response of the PR medium. One can switch these logic operations simply by means of the on-off control of the signal and the pump beam illumination. We analyze the spatial distribution of beam intensity in these logic gates using a finite-difference beam propagation method (FD-BPM) and the crosstalk between adjoining pixels is examined from the result. We also experimentally verify that the XOR-, OR-, and AND-gates are realized in the same optical setup.     

Ultrafast all-optical switching in a silicon-polymer compound slotted photonic crystal nanobeam cavity

Optical Review - On-chip ultrafast all-optical switching is highly desirable and important for all-optical information processing and photonic integrated circuits (PIC). Although numerous...     

Polarization encoded all-optical quaternary successor with the help of SOA assisted Sagnac switch

The application of multi-valued (non-binary) signals can provide a considerable relief in transmission, storage and processing of large amount of information in digital signal processing. Optical multi-valued logical operation is an interesting challenge for future optical signal processing where we can expect much innovation. A novel all-optical quaternary successor (QSUC) circuit with the help of semiconductor optical amplifier (SOA)-assisted Sagnac switch is proposed and described. This circuit exploits the polarization properties of light. Different logical states are represented by different polarization state of light. Simulation result confirming described method is given in this paper. Proposed all-optical successor circuit can take an important and significant role in designing of all-optical quaternary universal inverter and modulo arithmetic unit (addition and multiplication).     

研制超宽带全光取样示波器设备

全光取样示波器是研究与开发超高速光通信系统和光子交换网络的关键性测试仪器设备. 本文简介了我们自行设计和研制出的超宽带全光取样示波器设备的实验样机系统, 并报道了我们已取得的初步实验结果. 采用自主研发的高稳定性被动锁模飞秒光纤激光器作为该光学示波器的光脉冲取样源, 我们通过利用高度非线性光纤中的四波混频效应, 成功地实现了对脉宽为1.8ps、重复频率分别为10GHz和40GHz的光脉冲信号的全光取样. 然后通过数字信号处理和计算机图形处理, 得到了再现后的超短光脉冲信号波形, 并测出了其脉冲宽度值为2.3ps. 借助于该光学取样示波器实验样机, 我们还成功地完成了对脉宽为1.8ps、经过伪随机数据序列调制后的10Gbit/s和40Gbit/s光数据信号眼图的精确测量. 这是我国首次报道有关超宽带全光取样示波器设备的实际研制工作及其相应的实验测试结果. 所得到的有关超短光脉冲信号波形的测试结果也与用70GHz宽带电子示波器和超快光电探测器组成的常规光电测量系统所获得的结果进行了比较, 清楚地表明了我们研制出的全光取样示波器实验样机比后者具有更高的时间分辨率和更大的测量带宽.     

All-optical method for maintaining a fixed intensity level of a light signal in optical computation

In data and image processing the role of optics is already well established. Due to inherent parallelism the optical systems run faster than its electronic counterparts. Optical nonlinear material can be used as a successful optical switch. The primary requirement for proper functioning of such nonlinear material based logic devices is a fixed intensity level of the optical signal against a specific logic state. In this communication, the authors propose a new concept to obtain a fixed intensity level of optical signal against a specific logic state for data processing. The scheme may extend a tremendous application not only to the area of all-optical computation, but also to optical communication process.     

Mach-Zehnder interferometer-based tree architecture for all-optical logic and arithmetic operations

Interferometric devices for optical processing have been of great interest in recent years. Semiconductor optical amplifier (SOA)-based Mach-Zehnder interferometer (MZI) has already taken a significant role in the field of ultra-fast all-optical signal processing. Optical tree architecture (OTA) provides important contributions in optical interconnecting networks. In this communication, we have tried to exploit the advantages of both OTA and SOA-based MZI switches. We have proposed SOA-MZI-based tree architecture, a new and alternative scheme, for integrated all-optical logic and arithmetic operations. This architecture can enable one to perform all-optical processing of signals, including two input logic operations, half-adder, full-adder, full-subtractor, one-bit data comparator, etc.     

Design of ternary Multiplexer and De-multiplexer circuit with optical nonlinear material (OPNLM) based switch

Multiplexer and De-multiplexer operation play a very important role in all-optical computation, communication and control. Considerable number of multiplexing – de-multiplexing scheme in digital optical processing have already been reported. A design of all-optical ternary Multiplexer De-multiplexer circuit with optical nonlinear material (OPNLM) based switch is proposed and described in this paper. Different logic states have been represented by different polarization states of light. Logical simulation is also included here. This circuit will be useful in future all-optical multi-valued logic based computing and information processing system.     

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.     

All-optical frequency-encoded inversion operation with tristate logic using reflecting semiconductor optical amplifiers

Optics has already proved its strong potential in information and data processing because of its inherent parallelism. Several all-optical data processors were proposed since the last few decades. Again it is also known that tristate operations can be well accommodated with optics in data and information processing, as this type of operation can enhance the information quality and capacity. Very recently, the concept of frequency variant encoding /decoding technique has been established because of its basic advantages. The potential advantage of frequency-dependent encoding/decoding is that, as the frequency is the fundamental character of a signal, it will remain unaltered in reflection, refraction, absorption, etc. during transmission. In this communication, the authors therefore propose a method of implementing frequency-encoded inversion logic operations with tristate logic using reflecting semiconductor optical amplifiers (RSOA).     

纳米光子学全光开关研究进展

全光开关是全光网络和数字光信息处理的基本器件,该器件主要基于非线性光学原理.自激光发明以来,对该器件的研究已历时半个世纪.虽然全光开关的基础研究十分活跃,研究成果丰硕,但是至今尚未做出实用器件.文章分析了全光开关面临的困难, 指出只有在极小的时空条件下,也就是采用飞秒激光驱动的纳米尺寸器件,才有可能研制出低开关功率、高开关速度、低插入损耗的实用的全光开关器件.文章简要介绍了近10年来纳米全光开关的研究成果,包括纳米尺寸干涉仪开关（空间开关）、量子限制光双稳触发器（时间开关）、半导体光放大器的波长转换器（波长开关）、光子晶体带隙移动开关和表面等离子体激元开关（强度开关）等5类16种典型的纳米全光开关器件.     

Method of developing all-optical parallel to serial converter exploiting Kerr non-linearity of medium

Different all-optical logic operations, memory blocks etc. are developed using the inherent parallelism of optics. In any digital communication and computation system, the role of serial to parallel and parallel to serial data conversion are very much essential for making a data convenient for transition.Here in this paper, the authors propose a new scheme for developing an all-optical parallel to serial data conversion system by using optical J-K Flip-Flops and some logic gates based on optical non-linear switches. The uses of such switches are widely established in the area of optical parallel computation.This process can be extend for developing some all-optical digital devices like shift register, optical pulse counters etc. The proposed scheme deals with the best use of high parallelism of the optics, so the super-fast processing speed can be achieved.     

All-optical computation — A parallel integrator based upon a single gate full adder

The achievement of low power all-optical bistability in small semiconductor devices at the end of the 1970's led to an upsurge in interest in all-optical information processing and optical computing. Based on the proven characteristics of existing bistable systems designs are put forward in this paper for a parallel optical integrator, using a single bistable element for full-adder operation. Optical storage or beam delay computational loops, and time-series to space-parallel conversion designs are presented.     

A method of generating single optical pulse in nanosecond range with the joint uses of electro-optic modulator and nonlinear material

Optics has already been established as a successful candidate in data processing. Lots of all-optical data processors are proposed in the last few decades. Again it is well-known that, in many situations, an optical single pulse is very much useful to trigger an optical data processing circuit. In this communication the authors propose a method of generating a sub-nanosecond optical pulse using electro-optic modulator and nonlinear material.