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Optical Switch (optical + switch)
Selected AbstractsA Light-Driven Supramolecular Optical Switch,ANGEWANDTE CHEMIE, Issue 40 2009Shin-nosuke Uno Reversibles Wechseln der Fluoreszenzemission eines DNA-basierten optischen Schalters von Blau zu Grün gelingt mit modulierendem Licht unterschiedlicher Wellenlänge (siehe Bild). Grundlage ist die Hybridisierung zweier pyrenfunktionalisierter DNA-Stränge in Gegenwart eines photochromen azobenzolhaltigen Effektorliganden, sofern dieser cis -konfiguriert vorliegt. Als Folge der Hybridisierung tritt die Excimerfluoreszenz von Pyren auf. [source] Design of a Multistage Optical Packet SwitchEUROPEAN TRANSACTIONS ON TELECOMMUNICATIONS, Issue 5 2000Carla Raffaelli Optical packet switching is considered as a means to achieve high speed networking in future optical multi-service networks, Optical switches of limited size are feasible with present-day photonic technology, so solutions for the design and implementation of large switches are proposed here. They are based on a multistage architecture built using small switching modules with output queuing, organised according to a Clos topology. Many degrees of freedom are available for switch design and they are exploited to achieve performance optimisation in relation to packet loss. Simulation and analytical tools are developed to evaluate switch architecture performance. Results and application examples are given to show the feasibility of the multistage architecture for optical networking. [source] Determination of activation temperature of glass bulb sprinklers using a thermal liquid bathFIRE AND MATERIALS, Issue 4 2006Mohammed M. Khan Abstract A thermal liquid bath was used to determine the activation temperature of a wide range of temperature rated (57,182°C) glass bulb (3 and 5 mm diameters) sprinklers using water and glycerine. An optical switch and a thermocouple were installed adjacent to each sprinkler (within 10 mm) to record the activation of each glass bulb in the liquid bath having a uniform temperature distribution (±0.5°C). All the tests for determining the activation temperatures of glass bulb sprinklers were conducted in the liquid bath using a 0.277°C/min rate of temperature rise. Based on a heat transfer analysis, this rate is within the maximum allowable rate of rise of water and glycerine temperatures, which allows the glass bulb temperature to closely follow the liquid temperature. The sprinkler activation temperature was evaluated in terms of percentage rating, which is expressed as the percent variation of the average activation temperature, as measured in the liquid bath, from the nominal rated temperature. Sprinklers (93°C rated or lower) activation temperatures in water were consistently within ±3.5% of rating. In glycerine, the activation temperatures of sprinklers rated between 93 and 182°C performed within 3.5% of their rating. Copyright © 2005 John Wiley & Sons, Ltd. [source] Optical switch dimensioning and the classical occupancy problemINTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 2-3 2002Vincenzo Eramo Abstract Results for optical switch dimensioning are obtained by analysing an urn occupancy problem in which a random number of balls is used. This analysis is applied to a high speed bufferless optical switch which uses tuneable wavelength converters to resolve contention between packets at the output fibres. Under symmetric packet routing the urn problem reduces to the classical occupancy problem. Since the problem is large scale and the loss probabilities are small, exact analysis by combinatorial methods is problematic. As an alternative, we outline a large deviations approximation which may be generalised in various ways. Copyright © 2002 John Wiley & Sons, Ltd. [source] 16×16 Mirror type optical switch with integrated fiber alignment and steady switching stateMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2008Qinghua H. Chen Abstract This paper reports a micro electro mechanical system (MEMS) 16×16 free space optical switch based on high-reflectivity mirrors. The mirror monolithically integrated with the fiber grooves can enlarge its rotation angles up to 90°, and keep this as a steady state to steer the optical signal. The reflectivity of the mirror is measured to be 93.1 , 96.3%. The smallest fiber-mirror-fiber insertion loss is 2.1 dB by utilizing optiFocusTM collimating lensed fibers. Moreover, only about ±0.01 dB oscillating amplitude of insertion loss is provoked after the device is tested for 15 min for 5 , 90 Hz in the vertical vibration amplitude of 3 mm. In addition, excellent antifatigue performance of the mirror, which can endure more than 109 cycles of actuation, has been proven. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 3012,3016, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23879 [source] Optical design and performance of a novel multifunction optical deviceMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2008Q. H. Chen Abstract This letter presents a novel MEMS-based multifunction-integrated optical device capable of performing as variable optical power splitter (VOPS), optical switch (OS), and variable optical attenuator (VOA). The device manipulates the light with a binary-slope mirror driven by compound electrostatic actuator. The optical models for splitting and attenuating are investigated, respectively. Ball-lensed fibers are assembled with the device to achieve high coupling efficiency in this work. Measurements reveal that the excess loss of the device is less than 3 dB, and the controllable attenuation range is up to 39 dB. Moreover, polarization-dependent loss is less than 0.7 dB. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2185,2189, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23603 [source] Synthetic approaches to 3H -naphtho[2,1- b]pyrans and 2,3-dihydro-1H -naphtho[2,1- b]pyransJOURNAL OF HETEROCYCLIC CHEMISTRY, Issue 6 2009Amitabh Jha Naphtho[2,1- b]pyran nuclei are prevalent in natural products with significant biological and medicinal properties. 3,3-Disubstituted 3H -naphtho[2,1 -b]pyrans are photochromic and find use in electronic display systems, ophthalmic lenses, optical switches, and temporary or permanent memories. Of the various possible structural isomers of naphthopyran framework, this review is an account of reported synthetic procedures to produce 3H -naphtho[2,1-b]pyrans and their dihydro analogs, 2,3-dihydro-1H -naphtho[2,1 -b]pyrans. The advantages and disadvantages of each procedure in terms of yields, complexity, formation of side-products, use of uncommon/expensive reagents, etc., are also described. J. Heterocyclic Chem., (2009). [source] A High-Content Diarylethene Photochromic Polymer for an Efficient Fluorescence ModulationMACROMOLECULAR RAPID COMMUNICATIONS, Issue 20 2006Yong-Chul Jeong Abstract Summary: A highly fluorescent photochromic polymer, poly-BTFO4, was prepared. The fluorescence quantum yield of the poly-BTFO4 was six times higher than that of BTFO4. Fatigue resistance of the polymer at its photostationary state was significantly enhanced compared with that of BTFO4. Importantly, the poly-BTFO4 film also showed an efficient photochromism as well as strong fluorescence similar to the results in solution, which allow photoinduced fluorescence switching applicable to optical switches. Improvement of fluorescence quantum yield and fatigue resistance. [source] Carrier-induced refractive index change in InNPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 2 2008C. Bulutay Abstract Rapid development of InN technology demands comprehensive assessment of the electronic and optoelectronic potential of this material. In this theoretical work the effect of free electrons on the optical properties of the wurtzite phase of InN is investigated. The blue shift of the optical absorption edge by the free-carrier band filling is known as the Burstein-Moss effect for which InN offers to be a very suitable candidate as has been recently demonstrated experimentally. Due to well known Kramers-Kronig relations, a change in absorption is accompanied by a change in the index of refraction. Considering n-type InN samples with free electron concentrations ranging from 5×1017 to 5×1020 cm,3, and employing a nonlocal empirical pseudopotential band structure, it is shown that this leads to a few percent change of the index of refraction. These carrier-induced refractive index changes can be utilized in optical switches, futhermore it needs to be taken into account in the design of InN-based optical devices such as lasers and optical modulators. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Proceedings of the 3rd International Conference on Physics of Light,Matter Coupling in Nanostructures (PLMCN3)PHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 6 2004Alexey Kavokin The 3rd International Conference on Physics of Light,Matter Coupling in Nanostructures (PLMCN3) took place in Acireale, Sicily, Italy from 1,4 October 2003. The aim of this conference was to review the fundamental background for realization of a new generation of opto-electronic devices such as polariton lasers, new optical switches and emitters based on microcavities. The idea was to combine the experience of spectroscopists and theorists with that of specialists in crystals growth of wide-band semiconductors (GaN, CdTe, ZnSe, ZnO) and organic materials. [source] | |||||||||||||