Digital computing with optics

Some of the current uses of optics in digital computing such as storage and networking, and the projected uses of optical interconnects are described. Several architectures that are being explored for optoelectronic computing are also described. These architecture are based on either the speed or the parallelism that is possible with optical systems. One or more of these architectures should prove fruitful within the next five years     

Space-time complexity in optical computing

Given certain simple and well defined operations and complexity measures, the product of spatial complexity with temporal complexity must exceed a certain minimum problem complexity if that processor is to solve that problem. Some optical processors violate that condition in a favorable direction (anomalously small temporal complexity). We next extend the requirement to embrace those optical processors. In its final form, the theorem requires that the product of spatial, temporal, and fanin complexities equal or exceed the problem complexity.Some parts of this work were presented at the SPIE symposium Optical Information Processing Systems and Architectures II, in San Diego, California, July 1990.     

Digital rights management in ubiquitous computing

The Internet has revolutionized multimedia content distribution, shifting the way content producers and users approach digital rights. However, ubiquitous computing will alter the digital rights management environment even more, and current techniques are ill equipped to deal with the changes. Distributed trust can help to overcome the challenge of maintaining digital rights for ubiquitous computing, using cellular automata to measure trust levels across a system.     

Reconfigurable optical interconnections for parallel computing

We describe our research on optically interconnected optoelectronic parallel computing systems. Our architecture is based on a multilayer pipeline of two-dimensional optoelectronic device arrays in which each pixel is composed of an optical input channel, a general-purpose programmable processor, local memory, and a surface-emitting laser diode as an optical output channel. Free-space optics provides parallel, global communication between layers in the pipeline via optical paths that are dynamically reconfigurable. Design and initial realization of a system are described     

网格计算在大规模光学计算中的应用

概要介绍了网格计算的基本原理和研究背景,以及网格计算的特点、应用和目前的研究现状.着重提出了一种应用于光学设计的网格计算系统,对这个系统的任务调度、通信方式以及整个作业的具体实施过程展开讨论.并且构建了一种网格仿真实验,用来测试本系统的运行情况,重点检测网格系统对整个作业执行的时间跨度长短和负载均衡性的好坏.仿真实验的结果表明,本网格计算系统对作业执行的时间跨度随着节点的增加成倍减小,在均衡负载等方面也有显著的效果,运行状况良好.     

Optoelectronic InP-InGaAs smart pixels for optical interconnectionsand computing

We describe InP-InGaAs optoelectronic smart pixels for applications in optical interconnection and computing. These circuits consist of monolithically integrated p-i-n photodiodes, heterojunction bipolar transistor (HBT) receivers and transmitters, and surface-bonded folded-cavity surface-emitting lasers (FCSEL's). Design, fabrication, and performance of two different circuits: a high-sensitivity pixel, and a high-bandwidth pixel with logic functions are discussed. We achieve a minimum switching energy of 6 fJ, a maximum pixel bandwidth of 800 MHz, and an optoelectronic gain of 3. To our knowledge, these are the best overall performance characteristics of any optoelectronic smart pixel technology and are competitive or superior to that achieved using all-electronic interconnects     

Digital MEMS for optical switching

Over the last few years an amazing amount of interest has emerged for applications of micro electro-mechanical systems (MEMS) in telecommunications. Silicon-based optical MEMS have proven to be the technology of choice for low-cost scalable photonic applications because they allow mass manufacturing of highly accurate miniaturized parts, and use materials with excellent mechanical and electrical properties. Applications include tunable lasers, optical switches, and tunable filters. The use of MEMS for optical switching has turned out to be most attractive since this application could revolutionize fiber optic telecommunications. We discuss the technology, performance, and reliability of 2D MEMS optical switches. We show that this technology meets the scalability, performance, and reliability requirements for important applications in fiber optic networks     

An optical multi-mesh hypercube: a scalable optical interconnectionnetwork for massively parallel computing

A new interconnection network for massively parallel computing is introduced. This network is called an optical multi-mesh hypercube (OMMH) network. The OMMH integrates positive features of both hypercube (small diameter, high connectivity, symmetry, simple control and routing, fault tolerance, etc.) and mesh (constant node degree and scalability) topologies and at the same time circumvents their limitations (e.g., the lack of scalability of hypercubes, and the large diameter of meshes). The OMMH can maintain a constant node degree regardless of the increase in the network size. In addition, the flexibility of the OMMH network makes it well suited for optical implementations. This paper presents the OMMH topology, analyzes its architectural properties and potentials for massively parallel computing, and compares it to the hypercube. Moreover, it also presents a three-dimensional optical design methodology based on free-space optics. The proposed optical implementation has totally space-invariant connection patterns at every node, which enables the OMMH to be highly amenable to optical implementation using simple and efficient large space-bandwidth product space-invariant optical elements     

Digital and analog optical broad-band transmission

The paper describes several experimental digital and analog optical broad-band transmission systems and characterizes the problems which had to be solved to realize these systems. The experiences gained are described and discussed with respect to the future development of digital and analog optical broad-band transmission technique.     

Digital demodulator for optical FSK signals

The authors present a novel FSK-demodulator for optical phase diversity receivers. It is based on a digital flip-flop and is shown to have a sensitivity of about 3 dB below that of a delay and multiply demodulator. The concept is a step towards a fully integrated low-cost FSK receiver.<>     

一种新型高速四进制光计算算法研究

提出了一种面向多级调制格式的先进高速光计算算法,利用高非线性光纤中超快简并和非简并四波混频(FWM),采用100Gb/s正交相位调制(DQPSK)信号,仿真实验实现了50Gbaud/s高速光计算,包括加法、双定向减法、补码、加倍等光计算功能。当比特误码率(BER)为10-9时,测得高速光计算的功率代价小于4dB。     

Naive-LSTM based services awareness of edge computing elastic optical networks

Great challenges and demands are presented by increasing edge computing services for current elastic optical networks(EONs) to deal with serious diversity and complexity of these services. To improve the match degree between edge computing and optical network, the services awareness function is necessary for EON. This article proposes a Naive long short-term memory(Naive-LSTM) based services awareness strategy of the EON, where the Naive-LSTM model makes full use of the most simplified structure...     

Digital transport of HDTV on optical fiber

An overview of the broadband integrated services digital network (BISDN) is given. A codec that compresses high-definition television to fit within the roughly 135-Mb/s capacity of a synchronous optical network synchronous transport signal level 3c (SONET STS-3c) signal carrying BISDN asynchronous transfer mode (ATM) cells, thus requiring compression of roughly only 6:1, is described. The order and format of the transmitted HDTV data is considered. ATM adaption and user layer information are discussed. Error control in the user layer is addressed     

Digital pulse interval modulation for optical communications

This article presents a study of digital pulse interval modulation (DPIM) for optical wireless communications using intensity modulation with direct detection. The DPIM code properties are discussed, and expressions for the transmission capacity, power spectrum, and error probability are presented. We show that for a given number of bits per symbol, DPIM has a higher transmission capacity, a similar spectral profile, and only a marginally inferior error probability performance compared with pulse position modulation, and is rather less complex to implement. Finally, problems associated with the nonuniform symbol length characteristics of DPIM together with possible solutions are discussed     

Digital fibre transmission using optical homodyne detection

Homodyne detection of a 140 Mbit/s PSK signal transmitted over 30 km of cabled fibre has been achieved using a balanced optical phase-locked-loop receiver. System phase error was dominated by the laser frequency instability and not the cabled fibre.     

时分多路可通话的光通信传输系统实验装置

介绍了数字时分多路可通话的光通信传输系统实验装置的设计原理和实现方案,具体介绍了系统各模块电路设计思路,简述了光接口实验测试方法和通话实验方法.     

Quantitative analysis on the computing performance improvement by parallel optical interconnection

This paper compares the optical and electrical interconnect systems by analyzing the efficiency and evaluating the total processing time, and design an experiment to demonstrate this performance promotion. With the increasing demand on large-scale parallel computing tasks, data transmission instead of data computing has become more and more important, so the rapid development of optical chip-to-chip interconnects techniques has gotten more attention. In this paper, we take fast Fourier transform (FFT) computation as an example to study whether and how the optical interconnection has influence on the computing performance, and three topology models are used to judging the transmission latency, and the relationship between the total processing time and the FFT points is also under investigation. Both results show parallel optical interconnection can bring large advantages in promoting computing performance. It is also found that the larger the transmission scale is, the more saving optical interconnection makes.     

Efficient reversible NOR gates and their mapping in optical computing domain

Reversible logic is a computing paradigm in which there is a one to one mapping between the input and the output vectors. Reversible logic gates are implemented in an optical domain as it provides high speed and low energy computations. In the existing literature there are two types of optical mapping of reversible logic gates: (i) based on a semiconductor optical amplifier (SOA) using a Mach–Zehnder interferometer (MZI) switch; (ii) based on linear optical quantum computation (LOQC) using linear optical quantum logic gates. In reversible computing, the NAND logic based reversible gates and design methodologies based on them are widely popular. The NOR logic based reversible gates and design methodologies based on them are still unexplored. In this work, we propose two NOR logic based n-input and n-output reversible gates one of which can be efficiently mapped in optical computing using the Mach–Zehnder interferometer (MZI) while the other one can be mapped efficiently in optical computing using the linear optical quantum gates. The proposed reversible NOR gates work as a corresponding NOR counterpart of NAND logic based Toffoli gates. The proposed optical reversible NOR logic gates can implement the reversible boolean logic functions with a reduced number of linear optical quantum logic gates or reduced optical cost and propagation delay compared to their implementation using existing optical reversible NAND gates. It is illustrated that an optical reversible gate library having both optical Toffoli gate and the proposed optical reversible NOR gate is superior compared to the library containing only the optical Toffoli gate: (i) in terms of number of linear optical quantum gates when implemented using linear optical quantum computing (LOQC), (ii) in terms of optical cost and delay when implemented using the Mach–Zehnder interferometer.     

A new method for computing nonlinear carrier diffusion insemiconductor optical devices

The solution of carrier diffusion equations typically associated with semiconductor optical devices has been achieved by combining a function expansion scheme, using the Hermite-Gauss functions as the basis set, with the collocation numerical procedure. Results for a wide range of cases obtained by this new scheme compare very favorably with those calculated with other methods. Not only is the present process computationally fast and efficient, but it has the added attraction of providing the basis for conveniently solving also the nonlinear electromagnetic wave equation for the self-consistent modeling of such devices