Integrated optical backplane amplifier

A solution for compensating losses in optical interconnects is provided. Large-core Al2O3:Nd3+ channel waveguide amplifiers are characterized and tested in combination with passive polymer waveguides. Coupling losses between the two waveguides are investigated in order to optimize the channel geometries of the two waveguide types. A tapered Al2O3:Nd3+ waveguide is designed to improve the pump intensity in the active region. A maximum 0.21-dB net gain at a signal wavelength of 880 nm is demonstrated in a structure in which an Al2O3:Nd3+ waveguide is coupled between two polymer waveguides. The gain can be improved by increasing the pump power and adjusting the waveguide properties of the amplifier

Nanomanufacturing and U.S. Competitiveness: Challenges and Opportunities

Nanotechnology has been defined as the control or restructuring of matter at the atomic and molecular levels in the size range of about 1–100 nanometers (nm); 100 nm is about 1/1000th the width of a hair. The U.S. National Nanotechnology Initiative (NNI), begun in 2001 and focusing primarily on R&D, represents a cumulative investment of almost $20 billion, including the request for fiscal year 2014. As research continues and other nations increasingly invest in R&D, nanotechnology is moving from the laboratory to commercial markets, mass manufacturing, and the global marketplace. Today, burgeoning markets and nanomanufacturing activities are increasingly competitive in a global context—and the potential EHS effects of nanomanufacturing remain largely unknown. GAO was asked to testify on challenges to U.S. competitiveness in nanomanufacturing and related issues. Our statement is based on GAO’s earlier report on the Forum on Nano-manufacturing, which was convened by the Comptroller General of the United States in July 2013 (GAO 2014; also referred to as GAO-14-181SP). That report reflects forum discussions as well as four expert-based profiles of nano-industry areas, which GAO prepared prior to the forum and which are appended to the earlier report

Migration from electronics to photonics in multicore processor

Thesis (M. Eng.)--Massachusetts Institute of Technology, Dept. of Materials Science and Engineering, 2008.Includes bibliographical references (leaf 54).Twenty - first opportunities for Gigascale Integration will be governed in part by a hierarchy of physical limits on interconnect. Microprocessor performance is now limited by the poor delay and bandwidth performance of the on - chip global wiring layer. This thesis is envisioned as a critical showstopper of electronic industry in the near future. The physical reason behind the interconnect bottleneck is the resistive nature of metals. The introduction of copper in place of aluminum has temporarily improved the interconnect performance, but a more disruptive solution will be required in order to keep the current pace of progress, optical interconnect is an intriguing alternative to metallic wires. Many - core microprocessors will push performance per chip from the 10 gigaflop to the 10 teraflop range in the coming decade. Pin limitations, the energy cost of electrical signaling, and the non - scalability of chip - length global wires are significant bandwidth impediments. Silicon nanophotonic based many core architecture are introduced in order to meet the bandwidth requirements at acceptable power levels.by Zhoujia Xu.M.Eng

Communications and control for electric power systems: Power system stability applications of artificial neural networks

This report investigates the application of artificial neural networks to the problem of power system stability. The field of artificial intelligence, expert systems, and neural networks is reviewed. Power system operation is discussed with emphasis on stability considerations. Real-time system control has only recently been considered as applicable to stability, using conventional control methods. The report considers the use of artificial neural networks to improve the stability of the power system. The networks are considered as adjuncts and as replacements for existing controllers. The optimal kind of network to use as an adjunct to a generator exciter is discussed

Advanced space power requirements and techniques. Task 1: Mission projections and requirements. Volume 1: Technical report

The objectives of this study were to: (1) develop projections of the NASA, DoD, and civil space power requirements for the 1980-1995 time period; (2) identify specific areas of application and space power subsystem type needs for each prospective user; (3) document the supporting and historical base, including relevant cost related measures of performance; and (4) quantify the benefits of specific technology projection advancements. The initial scope of the study included: (1) construction of likely models for NASA, DoD, and civil space systems; (2) generation of a number of future scenarios; (3) extraction of time phased technology requirements based on the scenarios; and (4) cost/benefit analyses of some of the technologies identified

Dependability enhancing mechanisms for integrated clinical environments

In this article, we present a set of lightweight mechanisms to enhance the dependability of a safety-critical real-time distributed system referred to as an integrated clinical environment (ICE). In an ICE, medical devices are interconnected and work together with the help of a supervisory computer system to enhance patient safety during clinical operations. Inevitably, there are strong dependability requirements on the ICE. We introduce a set of mechanisms that essentially make the supervisor component a trusted computing base, which can withstand common hardware failures and malicious attacks. The mechanisms rely on the replication of the supervisor component and employ only one input-exchange phase into the critical path of the operation of the ICE. Our analysis shows that the runtime latency overhead is much lower than that of traditional approaches

ELECTROMAGNETIC MODELING WITH A NEW 3D ALTERNATING-DIRECTION-IMPLICIT (ADI) MAXWELL EQUATION SOLVER

We introduce a time-domain method to simulate the digital signal propagation along on-chip interconnects, aperture radiation, and indoor-communication by solving the Maxwell equation with the Alternating-Direction-Implicit (ADI) method. With this method, we are able to resolve the large scale (i.e. electromagnetic wave propagation) and fine scale (i.e. metal skin depth, substrate current, coating material) structure in the same simulation, and the simulation time step is not limited by the Courant condition. The simulations allow us to calculate in detail parasitic current flow inside the substrate; propagation losses, skin-depth and dispersion of digital signals on non-ideal interconnects; detailed surface current and standing wave pattern in aperture radiation problem; signal power map and propagation delay in complicated in-door communication scenario