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.     

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.     

A new scheme of all-optical adder logic operation based on nonlinear property of the material and polarization encoding technique

Optical nonlinear materials have been used for several digital logic and arithmetic operations. These operations are conducted in real time domain as per their operational speed is concerned. In this paper authors propose a new method of all optical half adder scheme. This type of switching is based on polarization properties of light along with nonlinear properties of material. As the state of polarization of light ensures that the field intensity level of the light signal is the same in whole operation, the scheme may be extended to some wide applications in all optical parallel computation and information processing.     

All-optical Serial Data Transfer between Registers using optical non-linear materials

The inherent parallelism of optical signal is an advantageous feature for high-speed computations and other digital logic operations. Different techniques have been proposed for performing arithmetic, algebraic and logic operations using light as the information-carrier. Here we propose a new method for Serial Data Transfer between Registers using optical non-linear material. This system is all-optical in nature. Optical NAND gate and NOT gate are the basic building blocks of this system.     

When optical microscopy meets all-optical analog computing: A brief review

As a revolutionary observation tool in life science, biomedical, and material science, optical microscopy allows imaging of samples with high spatial resolution and a wide field of view. However, conventional microscopy methods are limited to single imaging and cannot accomplish real-time image processing. The edge detection, image enhancement and phase visualization schemes have attracted great interest with the rapid development of optical analog computing. The two main physical mechanisms that enable optical analog computing originate from two geometric phases: the spin-redirection Rytov-Vlasimirskii-Berry (RVB) phase and the Pancharatnam-Berry (PB) phase. Here, we review the basic principles and recent research progress of the RVB phase and PB phase based optical differentiators. Then we focus on the innovative and emerging applications of optical analog computing in microscopic imaging. Optical analog computing is accelerating the transformation of information processing from classical imaging to quantum techniques. Its intersection with optical microscopy opens opportunities for the development of versatile and compact optical microscopy systems.     

光学超振荡与超振荡光学器件

传统光学器件的衍射极限极大地制约了远场超分辨光学系统的进一步发展.如何从光学器件层面突破光学衍射极限瓶颈,实现非标记远场超分辨光学成像,是光学领域面临的巨大挑战.光学超振荡在不依靠倏逝波的条件下,可以在远场实现任意小的亚波长光场结构,这为突破光学衍射极限提供了一条崭新的途径.近年来,光学超振荡现象和超振荡光学器件的相关研究得到了快速发展,在理论和实验上成功地演示了超振荡光场的产生和多种超振荡光学器件,并在实验上展示了超振荡光学器件在非标记远场超分辨光学显微、成像以及超高密度数据存储等应用领域的巨大优势和应用潜力.本文对光学超振荡相关理论、超振荡光学器件设计理论和方法、超振荡光学器件发展现状、超振荡光场测试方法以及超振荡光学器件的应用等方面进行详细介绍和分析.     

Image amplifier for coherent optical active feedback in the 514 nm range

Optical feedback techniques will extend the region of possible applicationsof optics in data processing. Only a few different transfer functions can be obtained in a passive optical feedback system, but a wide variety of new possibilities can be suggested by introducing active elements (e.g. amplifiers and spatial phase modulators). A flashlamp pumped dye amplifier for optical feedback is presented and the resulting consequences for data processing systems are discussed.     

Optical response functions of ZnS, ZnSe, ZnTe by the LOM method

In recent years optical properties of nano-structures and semiconductors have gained increasing importance in many technological areas, such as blue laser fabrication techniques, optical switching devices, cascaded laser operations on chip sized platforms. In this work, the localized orbital method (LOM) is applied to compute the dielectric response functions for the semiconductors and the sample crystals of ZnS, ZnSe and ZnTe are taken into consideration. The bulk crystal response functions and atom-cavity optical responses are handled. This is the first application of LOM to optical properties of semiconductors.     

Alternating approach of implementing frequency encoded all-optical logic gates and flip-flop using semiconductor optical amplifier

In conduction of parallel logic, arithmetic and algebraic operations, optics has already proved its successful role. Since last few decades a number of established methods on optical data processing were proposed and to implement such processors different data encoding/decoding techniques have also been reported. Currently frequency encoding technique is found be a promising as well as a faithful mechanism for the conversion of all-optical processing as the frequency of light remains unaltered after refection, refraction, absorption, etc. during the transmission of light. There are already proposed some frequency encoded optical logic gates. In this communication the authors propose a new and different concept of frequency encoded optical logic gates and optical flip-flop using the non-linear function of semiconductor optical amplifier.     

All-optical conversion scheme from binary to its MTN form with the help of nonlinear material based tree-net architecture

In the field of optical computing and parallel information processing, several number systems have been used for different arithmetic and algebraic operations. Therefore an efficient conversion scheme from one number system to another is very important. Modified trinary number (MTN) has already taken a significant role towards carry and borrow free arithmetic operations. In this communication, we propose a tree-net architecture based all optical conversion scheme from binary number to its MTN form. Optical switch using nonlinear material (NLM) plays an important role.     

Ciphertext-only attacks on the double random phase encryption based on redundancy vulnerability

Optical Review - The double random phase encoding techniques have received considerable attention from researchers in recent years because of their advantages of parallel and high-speed processing...     

光学成像在疾病诊断中的应用

当前，医生们利用各种成像技术与疾病进行斗争，其中光学成像技术是获得高分辨率图像的新方法，其原理是每种生物介质具有各自特有的光谱特性，可赖以区分病变组织和正常组织，或对潜在问题准确定位。而光学相干层析则是最精确的光学成像技术，可提供１０～２０μｍ量级的高分辨率及比迄今为止任何其他技术都高的灵敏度。本文着重讨论光学相干层析术的基本原理及目前发展状况     

Characterization of the spectral phase of ultrashort light pulses

The complete characterization of a short light pulse requires the measurement of the value of the electric field as a function of time, or conversely, as a function of the optical frequency. Many different techniques have been demonstrated for this purpose. They fall in two main categories, whether a known reference pulse whose spectrum encompasses that of the unknown pulse is available or not. In the first case, linear techniques such as time-domain or frequency-domain interferometry can be directly used, with the advantage of a high sensitivity. In the latter case, non-stationary filters can be implemented using optical non-linearities, in techniques such as Frequency Resolved Optical Gating (FROG) or Spectral Phase Interferometry for Direct Electric-field Reconstruction (SPIDER).     

Time-stretch oscilloscope with dual-channel differential detection front end for monitoring of 100 Gb/s return-to-zero differential quadrature phase-shift keying data

Optical performance monitoring of high-capacity networks is one of the enabling technologies of future reconfigurable optical switch networks. In such networks, rapid performance evaluation of data streams becomes challenging due to the use of advanced modulation formats and high data rates. The time-stretch enhanced recording oscilloscope offers a potential solution to monitoring high-rate data in a practical time scale. Here we demonstrate an architecture with a differential detection front end for simultaneous I/Q data monitoring of a 100 gigabits/s return-to-zero differential quadrature phase-shift keying signal. This demonstration shows the potential of this technology for rapid performance monitoring of high-rate optical data streams that employ advanced modulation formats.     

One-step optical trinary signed-digit arithmetic using redundant bit representations

A simple one-step fully parallel trinary signed-digit arithmetic is proposed for parallel optical computing. This technique performs multidigit carry-free addition and borrow-free subtraction in constant time. The trinary signed-digit arithmetic operations are based on redundant bit representation of the digits. Optical implementation of the proposed arithmetic can be carried out using correlation or matrix multiplication based schemes. An efficient matrix multiplication based optical implementation that employs a fixed number of minterms for any operand length is developed. It is shown that only 30 minterms (less than recently reported techniques) are enough for implementing the one-step trinary addition and subtraction.     

Defects in room temperature solid inert gases

We report on the use of high resolution electron microscopy and optical processing techniques to study defects in solid inert gas precipitates (bubbles) formed by ion implantation into aluminium. Faceted precipitates, of the order of 5 run in length and epitaxial with the aluminium, in some cases exhibit a high degree of crystalline perfection but in others departure from the regular atomic arrangement is evident in the lattice images. Optical processing techniques have been applied to enhance the lattice images and in some cases to colour encode the aluminium and inert gas spacings present in the micrograph, with the aim of indentifying specific defect structures in the inert gas solid. We demonstrate that the solid “bubble”, formed in a metal by ion implantation, provides a means of studying defects in a simple insulator, the rare gas solid.     

A method of developing frequency encoded multi-bit optical data comparator using semiconductor optical amplifier

Optical data comparator is the part and parcel of arithmetic and logical unit of any optical data processor and it is working as a building block in a larger optical circuit, as an optical switch in all optical header processing and optical packet switching based all optical telecommunications system. In this article the author proposes a method of developing an all optical single bit comparator unit and subsequently extending the proposal to develop a n-bit comparator exploiting the nonlinear rotation of the state of polarization of the probe beam in semiconductor optical amplifier (SOA). Here the dataset to be compared are taken in frequency encoded/decoded form throughout the communication. The major advantages of frequency encoding over all other conventional techniques are that as the frequency of any signal is fundamental one so it can preserve its identity throughout the communication of optical signal and minimizes the probability of bit error problem. For frequency routing purpose optical add/drop multiplexer (ADM) is used which not only route the pump beams properly but also to amplify the pump beams efficiently. Switching speed of ‘MZI-SOA switch’ as well as SOA based switches are very fast with good on–off contrast ratio and as a result it is possible to obtain very fast action of optical data comparator.     

Optical strain analysis of composite and monolithic materials

Optical techniques of moiré, holography, speckle and thermographic stress analysis† are very effective for analysing engineering problems involving materials such as man-made (fibre reinforced) and natural (wood, paperboard) composites, metals and rubber. The photo-mechanical techniques are combined herein with computer-vision (digital-imaging) concepts. Attention is also devoted to hybrid methods for processing and differentiating recorded optical data. Applications include those to fracture, stress waves, paper physics, material behavior, wood engineering, energy storage, and hostile environments.     

Microscopy and single molecule detection in photosynthesis

Progress in various fields of microscopy techniques brought up enormous possibilities to study the photosynthesis down to the level of individual pigment-protein complexes. The aim of this review is to present recent developments in the photosynthesis research obtained using such highly advanced techniques. Three areas of microscopy techniques covering optical microscopy, electron microscopy and scanning probe microscopy are reviewed. Whereas the electron microscopy and scanning probe microscopy are used in photosynthesis mainly for structural studies of photosynthetic pigment-protein complexes, the optical microscopy is used also for functional studies.     

光导纤维在载荷测量及角位移测量中的应用

介绍了力学量中载荷和角位移的测量传感器。其方法是利用光导纤维作为传感器主要元件,被测载荷使弹性元件变形,使光纤端面间光的耦合效率发生变化,通过测量光通量的变化而测知载何和角位移的大小。在载荷测量中特殊布置光纤的位置,通过电路对信号的差分处理能达到提高传感器线性度的目的。最后的传感器输出结果其非线性大为减小。角位移的测试中,这种角位移光纤传感器灵敏度高,分辨率小,适合于扭转试件的微小角位移测量。这类光纤传感器用于力学量测试可弥补一些传统测量方法的不足。