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Circuits, Devices & Systems, IET

Issue 2 • Date March 2011

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Displaying Results 1 - 9 of 9
  • Editorial optical computing circuits, devices and systems

    Publication Year: 2011 , Page(s): 73 - 75
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (84 KB)  

    Information forms the basis of modern technology. To meet the ever-increasing demand for information, means have to be devised for a more efficient and better-equipped technology to intelligibly process data. Advances in photonics have made their impact on each of the four key applications in information processing, i.e., acquisition, transmission, storage and processing of information. The inherent advantages of ultrahigh bandwidth, high speed and low-loss transmission has already established fiber-optics as the backbone of communication technology. However, the optics to electronics inter-conversion at the transmitter and receiver ends severely limits both the speed and bit rate of lightwave communication systems. As the trend towards still faster and higher capacity systems continues, it has become increasingly necessary to perform more and more signal-processing operations in the optical domain itself, i.e., with all-optical components and devices that possess a high bandwidth and can perform parallel processing functions to eliminate the electronic bottleneck. View full abstract»

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  • Optical logic elementary circuits

    Publication Year: 2011 , Page(s): 76 - 83
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (537 KB)  

    Elementary blocks, performing logic operations, are the building elements for more complex subsystems implementing all-optical digital processing. They can potentially enable next generation optical networks and optical computing, overcoming the limitations of the electronics bandwidth, also guaranteeing scalability, transparency, easy reconfigurability and modularity. Finally, integrated technologies can reduce power consumption, footprint and cost. View full abstract»

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  • Low-power nanophotonic devices based on photonic crystals towards dense photonic network on chip

    Publication Year: 2011 , Page(s): 84 - 93
    Cited by:  Papers (14)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (725 KB)  

    The authors review their recent studies on various nanophotonic devices including all-optical switches, optical memories, electro-optic modulators, photo-detectors and lasers, all of which are based on photonic crystal (PhC) nanocavities. The strong light confinement achieved in PhC nanocavities has enabled these devices with ultrasmall footprint and ultralow power/energy consumption. These characteristics are ideally suited for constructing dense photonic network on chip, which will overcome the limitation of future CMOS chips in terms of high-speed operation with less energy consumption and heat generation. View full abstract»

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  • Integrated waveguide circuits for optical quantum computing

    Publication Year: 2011 , Page(s): 94 - 102
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (523 KB)  

    Although practical realisation of a fully functioning quantum computer is still a long way off, recent progress both experimentally and theoretically is paving the way for possible implementations. One of the leading approaches is quantum optics, where photons are used as carriers of quantum information, and are manipulated in both linear and non-linear optical circuits. More recently, advances in integrated quantum photonics are enabling the realisation of compact and stable quantum gates and circuits. This approach provides routes to enhancing the complexity of quantum optic experiments, and ultimately towards the development of advanced quantum technologies. This study presents an overview of recent developments in the field of integrated waveguide quantum circuits. Key building blocks required for the realisation of quantum circuits are presented, and a rudimentary version of Shor's quantum factoring algorithm is demonstrated. Planar waveguide quantum circuits provide a high-performance platform from which quantum technologies and experimental quantum physics using single photons can be developed, and a new generation of quantum information and computing devices can be monolithically integrated onto a single optical chip. View full abstract»

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  • Nanoparticles with logic and numeracy: towards 'computer-on-a-particle' optoelectronic devices

    Publication Year: 2011 , Page(s): 103 - 114
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (669 KB)  

    The review focuses on semiconductor nanoparticles and hybrid materials obtained by immobilisation of various molecular species on nanoparticulate semiconductors. These materials constitute unique systems combining collective properties of solids with structural diversity of molecules which show distinctive photoelectrochemical properties. Theoretical models of electronic interactions between molecules and semiconductor surfaces have been presented. Additionally, the review summarises the idea of small particles that can work as electronic devices. These devices are able to sense the environment and communicate with other devices and with the user. The devices are based on surface modified wide-band gap semiconductors and the photoelectrochemical photocurrent switching effect. This effect has created a new platform for novel chemical switches, logic gates and other information processing devices. The mechanism of photocurrent switching is discussed with respect to the type of surface complex-support interaction. Photoelectrochemical properties of multicomponent photoelectrodes based on wide band gap nanocrystaline semiconductors modified with various molecules were investigated. The review presents some examples of hybrid materials working as logic devices, including reconfigurable ones and simple arithmetic systems together with mechanistic problems related to nanoscale information processing. View full abstract»

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  • All-optical logic gate in silicon nanowire optical waveguides

    Publication Year: 2011 , Page(s): 115 - 122
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (664 KB)  

    In this study, the authors propose a novel optical waveguide consisting of arrays of silicon nanowires (SiNWs) in close proximity for applications to all-optical logic operations. The logic operations are based on two non-linear phenomena, stimulated Raman scattering (SRS) and free carrier absorption (FCA). Since, the SRS coefficient is increased in the nanowire regime, the performance of the optical logic gates in terms of optical power required can be improved by a factor of at least 7 using our proposed waveguides. The advantage of the proposed waveguide is that it allows for increased photon-carrier interactions while keeping the optical confinement factor high even when the individual nanowire diameters are less than 100 nm. We analyse the waveguides using the finite-difference time domain method and show that the radiation loss is less than 0.034 cm-1. Further, the waveguide allows for optical guidance even when the nanowires are randomly arranged. We also show a maskless etch method to create SiNWs with dimensions required to create our proposed waveguide structure. View full abstract»

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  • All-optical binary to gray code and gray to binary code conversion scheme with the help of semiconductor optical amplifier-assisted sagnac switch

    Publication Year: 2011 , Page(s): 123 - 131
    Cited by:  Papers (3)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1037 KB)  

    Gray codes are widely used to facilitate error correction in digital communications. An all-optical four-bit binary to Gray code and Gray to binary code converter with the help of semiconductor optical amplifier-assisted Sagnac switch is proposed and described. This study describes all-optical conversion scheme using a set of all-optical switches. The new method promises both higher processing speed and accuracy. Numerical simulation result confirming the described methods and conclusion are given here. View full abstract»

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  • Interferometric switch based all optical scheme for conversion of binary number to its quaternary-signed digit form

    Publication Year: 2011 , Page(s): 132 - 142
    Cited by:  Papers (1)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (674 KB)  

    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. In arithmetical operation signed digit number is very essential for carry free computation. To achieve the parallelism in computation, a suitable number system and an efficient encoding/decoding scheme for handling the data are very much essential. In radix-4 system negative number is represented by quaternary-signed digit (QSD). In this study a conversion from 3-bit binary number (2>;s complement representation) to its equivalent single-digit QSD is reported. The technique for conversion of QSD to its binary equivalent form is also presented. All-optical circuits are designed with non-linear material-based interferometric switches such as terahertz optical asymmetric demultiplexer in optical tree architecture, where the numbers are represented by different discrete polarised state of light. Device-based simulation of the proposed optical circuit is used to verify the operation of the optical converter. View full abstract»

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  • Computer-aided design model for a quantum-cascade laser

    Publication Year: 2011 , Page(s): 143 - 147
    Cited by:  Papers (2)
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (317 KB)  

    This study presents a simple, single and an accurate computer-aided design model for quantum-cascade laser based on multi-layer perceptrons. Each critical quantity (optical gain, differential refractive index change, linewidth enhancement factor) that is used in the model requires long mathematical calculations with a strong background knowledge. In addition to that, these quantities use different theories, estimations and assumptions of some parameter values. The model tremendously decreases the computational time in the order of microseconds and is in very good agreement with previously published results. View full abstract»

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Aims & Scope

IET Circuits, Devices & Systems covers the following topics:

Circuit theory and design, circuit analysis and simulation, computer aided design; filters (analogue and switched capacitor); circuit implementations, cells and architectures for integration including VLSI; testability, fault tolerant design, minimisation of circuits and CAD for VLSI; novel or improved electronic devices for both traditional and emerging technologies including nanoelectronics and MEMs, device and process characterisation, device parameter extraction schemes; mathematics of circuits and systems theory; test and measurement techniques involving electronic circuits, circuits for industrial applications, sensors and transducers.

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