116 research outputs found
Numerical investigation of a feed-forward linewidth reduction scheme using a mode-locked laser model of reduced complexity
We provide numerical verification of a feed-forward, heterodyne-based phase noise reduction scheme using
single-sideband modulation that obviates the need for optical filtering at the output. The main benefit of a
feed-forward heterodyne linewidth reduction scheme is the simultaneous reduction of the linewidth of all modes
of a mode-locked laser (MLL) to that of a narrow-linewidth single-wavelength laser. At the heart of our simulator
is an MLL model of reduced complexity. Importantly, the main issue being treated is the jitter of MLLs and we
show how to create numerical waveforms that mimic the random-walk nature of timing jitter of pulses from
MLLs. Thus, the model does not need to solve stochastic differential equations that describe the MLL dynamics,
and the model calculates self-consistently the line-broadening of the modes of the MLL and shows good agreement with both the optical linewidth and jitter. The linewidth broadening of the MLL modes are calculated after
the phase noise reduction scheme and we confirm that the phase noise contribution from the timing jitter still
remains. Finally, we use the MLL model and phase noise reduction simulator within an optical communications
system simulator and show that the phase noise reduction technique could enable MLLs as optical carriers for
higher-order modulation formats, such as 16-state and 64-state quadrature amplitude modulation
The dielectric breakdown limit of silicone dielectric elastomer actuators
Soft silicone elastomers are used in a generation of dielectric elastomer actuators (DEAs) with improved actuation speed and durability compared to the commonly used, highly viscoelastic
polyacrylate 3M VHB films. The maximum voltage-induced stretch of DEAs is ultimately limited by their dielectric breakdown field strength. We measure the dependence of dielectric breakdown field strength on thickness and stretch for a silicone elastomer, when voltage-induced deformation is prevented. The experimental results are combined with an analytic model of equi-biaxial actuation to show that accounting for variable dielectric field strength results in different values of optimal pre-stretch and thickness that maximize the DEA actuation
Submicron Structures Fabrication and Research
Contains reports on thirteen research projects.Joint Services Electronics Program (Contract DAAG29-83-K-0003)U.S. Navy - Office of Naval Research (Contract N00014-79-C-0908)National Science Foundation (Grant ECS82-05701)I.B.M. (PO No. 90305-QPSA-559)U.S. Department of Energy (Contract DE-AC02-82-ER13019)Lawrence Livermore Laboratory (Contract 2069209
Reaction Front in an A+B -> C Reaction-Subdiffusion Process
We study the reaction front for the process A+B -> C in which the reagents
move subdiffusively. Our theoretical description is based on a fractional
reaction-subdiffusion equation in which both the motion and the reaction terms
are affected by the subdiffusive character of the process. We design numerical
simulations to check our theoretical results, describing the simulations in
some detail because the rules necessarily differ in important respects from
those used in diffusive processes. Comparisons between theory and simulations
are on the whole favorable, with the most difficult quantities to capture being
those that involve very small numbers of particles. In particular, we analyze
the total number of product particles, the width of the depletion zone, the
production profile of product and its width, as well as the reactant
concentrations at the center of the reaction zone, all as a function of time.
We also analyze the shape of the product profile as a function of time, in
particular its unusual behavior at the center of the reaction zone
Submicron Structures Technology and Research
Contains reports on fourteen research projects.Joint Services Electronics Program (Contract DAAG29-83-K-0003)U.S. Navy - Office of Naval Research (Contract N00014-79-C-0908)National Science Foundation (Grant ECS82-05701)Semiconductor Research Corporation (Grant 83-01-033)U.S. Department of Energy (Contract DE-ACO2-82-ER-13019)Lawrence Livermore National Laboratory (Contract 2069209)National Aeronautics and Space Administration (Contract NAS5-27591)Defense Advanced Research Projects Agency (Contract N00014-79-C-0908)National Science Foundation (Grant ECS80-17705)National Aeronautics and Space Administration (Contract NGL22-009-638
Gas Source Molecular Beam Epitaxy of Compound Semiconductors
Contains an introduction and reports on six research projects.Advanced Research Projects Agency Subcontract 284-25041Joint Services Electronics Program Contract DAAL03-92-C-0001National Center for Integrated Photonic Technology Contract 542-381National Science Foundation Grant DMR 92-02957National Science Foundation Contract DMR 92-02957National Science Foundation Grant DMR 90-2293
Submicron Structures Technology and Research
Contains reports on thirteen research projects.Joint Services Electronics Program (Contract DAAG29-83-K-0003)U.S. Navy - Office of Naval Research (Contract N00014-79-C-0908)National Science Foundation (Contract ECS82-05701)U.S. Department of Energy (Contract DE-ACO2-82-ER-13019)Lawrence Livermore Laboratory (Contract 2069209)National Aeronautics and Space Administration (Contract NGL-22-009-638)U.S. Navy - Office of Naval Research (Contract N00014-84-K-0073)National Science Foundation (Grant ECS80-17705)National Science Foundation (Grant ENG79-09980
Submicron Structures Fabrication and Research
Contains reports on twelve research projects.Lawrence Livermore Laboratory (Subcontract 2069209)Joint Services Electronics Program (Contract DAAG29-C-0104)U.S. Navy - Office of Naval Research (Contract N00014-79-C-0908)Joint Services Electronics Program (Contract DAAG29-80-C-0104)Harkness FoundationI.B.M.U.S. Department of Energy (Contract DE-ACO2-80-E10179)National Science Foundation (Grant ECS80-17705
Heterostructures for High Performance Devices
Contains table of contents for Part I, table of contents for Section 1, an introduction, reports on sixteen research projects and a list of publications.DARPA/NCIPTJoint Services Electronics Program Contract DAAL03-92-C-0001National Science FoundationToshiba Corporation Ltd.Charles S. Draper LaboratoriesHertz Foundation FellowshipVitesse SemiconductorGTE LaboratoriesNational Science Foundation FellowshipDARPA/MOSISTexas Instruments, Inc.U.S. Army Research Office Grant DAAL03-92-G-025
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