Subscribe free to our newsletters via your
. Space Travel News .




CHIP TECH
A faster path to optical circuits
by Staff Writers
Lausanne, Switzerland (SPX) Jun 17, 2014


File image.

Just as electronic circuits work with electrical charges, optical circuits process pulses of light, which gives them a distinct advantage in terms of speed. Optical technologies are therefore the object of intense research, aiming to develop novel optical devices that can control the flow of light at the nanometer scale.

EPFL scientists have developed a new method that can optimally design a widely-used class of optical devices with unprecedented effectiveness. Their designs have been fabricated in the US, at the University of Rochester, and successfully tested in Italy, at the University of Pavia. In two publications in Applied Physics Letters and Scientific Reports, the result of this collaboration will considerably speed up the development of optical circuits.

In order to use light for encoding information in future communication systems, it is first necessary to regulate its flow and retain it for even a fraction of a second, to avoid signal "traffic jams". This is achieved by optical nanocavities, which are arrangements of mirrors that force light to bounce between them and can therefore retain it in a small space.

They are widely used in lasers and optical devices, and are made from a variety of materials, such as silicon. Optical nanocavities are also ideal for building optical circuits, which regulate the flow of light just like conventional transistors regulate the flow of electrons. Optical circuits can also be integrated with electronic circuits into extremely compact structures to increase performance in information and communication technologies.

The most promising optical nanocavities are built inside structures called "photonic crystals", giving them the name "photonic crystal nanocavities (PCNs)". PCNs operate like the components of an electronic circuit, except they control the flow of light instead of the flow of electrons. Because of their complex geometry, the optimization of PCNs is a challenging task, requiring lengthy computer simulations of hundreds of possible designs before selecting the best for nanofabrication.

The group of Vincenzo Savona at EPFL has developed a novel method to design, simulate and optimize PCNs and applied it to one of the most common PCN types, used widely in commercial optical circuits. The goal was to maximize the PCN quality factor - a term that refers to the length of time the nanocavity can hold a photon before it escapes.

"Ideally you want to confine light as long as possible and inside a volume as small as possible", says Savona. "The nanocavities we are optimizing are smaller than the optical wavelength itself (about 1 micrometer) and have a quality factor higher than 1 million, meaning that a photon can go back and forth inside the nanocavity more than 1 million times before escaping."

The scientists perfected a computer modeling algorithm that can simulate a single PCN structure in matter of minutes -much faster than the several hours typically required by commercial tools. As PCN optimization requires simulating thousands of different structures, this new approach offers considerable advantages in terms of time and effectiveness.

The fast algorithm was combined with an optimization software tool that is referred to as 'genetic' or 'evolutionary' because it uses a kind of 'natural' selection to choose the best nanocavity structures.

The "evolutionary" process begins by regarding each PCN structure as an individual in a population, like animals in a herd. The individuals then "breed" between them, meaning that two single PCN structures combine to create a new one that is a cross-over between its two parents.

As PCN generations succeeded one another, Savona's algorithm rapidly simulated the structures, and the evolutionary software selected the best individuals - in this case, the ones that showed the best "fitness" with respect to a desired quality, e.g. photon lifetime or frequency. The entire process is fully automated and typically involves a few hundreds of generations, each including one hundred individuals. "Our fast method means that an optimization will typically take a couple of days on a computer", says Savona.

The best PCN designs were sent to a laboratory in the US to be nanofabricated on a silicon platform. From there, the PCNs were shipped to another laboratory in Italy, where they were successfully tested.

"In the end, we improved all of the most widespread PCN designs by a factor of 10-20 in terms of lifetime of the confined photons", Savona explains. The devices show some of the highest quality factors ever measured in PCNs, which can have a tremendous impact on the development of integrated photonic circuits.

.


Related Links
Ecole Polytechnique Federale de Lausanne
Computer Chip Architecture, Technology and Manufacture
Nano Technology News From SpaceMart.com






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





CHIP TECH
Researchers find weird magic ingredient for quantum computing
Waterloo, Canada (SPX) Jun 16, 2014
A form of quantum weirdness is a key ingredient for building quantum computers according to new research from a team at the University of Waterloo's Institute for Quantum Computing (IQC). In a new study published in the journal Nature, researchers have shown that a weird aspect of quantum theory called contextuality is a necessary resource to achieve the so-called magic required for universal qu ... read more


CHIP TECH
Nasa readies satellite to measure atmospheric CO2

Arianespace A World Leader In The Satellite Launch Market

Airbus Group and Safran To Join Forces in Launcher Activities

US not able yet to remove dependency on Russian rocket motors

CHIP TECH
Discovery of Earth's Northernmost Perennial Spring

US Congress and Obama administration face obstacles in Mars 2030 project

Opportunity Recovering From Flash Memory Problems

Rover Corrects its Spacecraft Clock

CHIP TECH
Solar photons drive water off the moon

55-year old dark side of the moon mystery solved

New evidence supporting moon formation via collision of 2 planets

NASA Missions Let Scientists See Moon's Dancing Tide From Orbit

CHIP TECH
Cracks in Pluto's Moon Could Indicate it Once Had an Underground Ocean

Hubble Begins Search Beyond Pluto For Potential Flyby Targets

Final Pre-Pluto Annual Checkout Begins

Assessing Pluto from Afar

CHIP TECH
Kepler space telescope ready to start new hunt for exoplanets

Astronomers Confounded By Massive Rocky World

Two planets orbit nearby ancient star

First light for SPHERE exoplanet imager

CHIP TECH
ULA Signs Multiple Contracts for Next-Gen Propulsion Work

Why We Need Rocket Engines

NASA again delays flying saucer test

Orion Ready To Feel The Heat

CHIP TECH
Chinese lunar rover alive but weak

China's Jade Rabbit moon rover 'alive but struggling'

Chinese space team survives on worm diet for 105 days

Moon rover Yutu comes closer to public

CHIP TECH
The Role Of Amateur Astronomers In Rosetta's Mission

Giant Telescopes Pair Up to Image Near-Earth Asteroid

NASA Instruments on Rosetta Start Comet Science

Asteroid Discovered by NASA to Pass Earth Safely




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement All images and articles appearing on Space Media Network have been edited or digitally altered in some way. Any requests to remove copyright material will be acted upon in a timely and appropriate manner. Any attempt to extort money from Space Media Network will be ignored and reported to Australian Law Enforcement Agencies as a potential case of financial fraud involving the use of a telephonic carriage device or postal service.