Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Optics: A step in time saves two

18.07.2013
A technique that reduces the time to simulate the operation of active optical devices aids the design of nanoscale lasers

Tiny optical components - the heart of modern communications systems - might one day increase the operational speed of computers. When designing these components, optical engineers rely on mathematical simulations to predict the performance and efficiency of potential devices. Now, Qian Wang at the A*STAR Data Storage Institute and co©workers have developed a neat mathematical trick that more than doubles the speed of this usually slow computation1. Their method also enables more accurate modeling of increasingly complicated structures.


An efficient FDTD simulation can quickly calculate the electric and magnetic field patterns inside a nanocavity laser. © 2012 IEEE

In the mid-nineteenth century, the physicist James Maxwell established a set of equations that describe the flow of light. The oscillating electric and magnetic fields of an optical pulse react to the optical properties of the medium through which it is travelling. "Combining Maxwell's equations with equations that describe light¨Cmatter interactions can provide a powerful simulation platform for optoelectronic devices," explains Wang. "However, running the computations is usually time-consuming."

Finite-difference time-domain (FDTD) simulations are a well-established method for modeling the flow of light in optical devices. This technique models a device as a grid of points and then calculates the electric and magnetic fields at each position using both Maxwell's equations and knowledge of the fields at neighboring points. Similarly, calculating the time evolution of light using Maxwell's equations is simplified by considering discrete temporal steps. Smaller spatial and temporal steps yield more accurate results but at the expense of a longer calculation time.

Electron density in a semiconductor is a key determiner of a material's optical properties. This density varies at a slower rate than the electric and magnetic fields of the optical pulse. Wang and his colleagues therefore eliminated calculation of this material property at every time step to shorten the calculation.

The researchers proved the usefulness of their approach by modeling a semiconductor laser, consisting of a cylindrical cavity 2 micrometers in diameter that traps light at its edges (see image). The trapped light supplies the optical feedback required for lasing. They simulated the operation of this device using an FDTD spatial grid with a 20-nanometer resolution and 0.033 femtosecond time steps. The calculated field pattern in the cavity was the same whether the active optical properties of the semiconductor were calculated at every time increment, or once every 100 steps. Yet, this simplification reduced the computation time by a factor of 2.2.

"Currently we are applying our approach to design integrated nanolasers as a next-generation on-chip light source for various applications," says Wang.

The A*STAR-affiliated researchers contributing to this research are from the Data Storage Institute

References
Ravi, K., Wang, Q. & Ho, S.-T. Efficient FDTD simulation of active photonic devices with multiple temporal resolutions. IEEE Photonics Technology Letters 24, 584¨C586 (2012).

A*STAR Research | Research asia research news
Further information:
http://www.research.a-star.edu.sg/research/6702
http://www.researchsea.com

More articles from Physics and Astronomy:

nachricht UNH scientists help provide first-ever views of elusive energy explosion
16.11.2018 | University of New Hampshire

nachricht NASA keeps watch over space explosions
16.11.2018 | NASA/Goddard Space Flight Center

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland

15.11.2018 | Earth Sciences

When electric fields make spins swirl

15.11.2018 | Physics and Astronomy

Discovery of a cool super-Earth

15.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>