Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Etching holes in vertical-cavity surface-emitting lasers creates better beam

11.02.2004


Researchers at the University of Illinois at Urbana-Champaign have found a way to significantly improve the performance of vertical-cavity surface-emitting lasers by drilling holes in their surfaces. Faster and cheaper long-haul optical communication systems, as well as photonic integrated circuits, could be the result.



Low-cost VCSELs are currently used in data communication applications where beam quality is of little importance. To operate at higher speeds and over longer distances, the devices must function in a single transverse mode with a carefully controlled beam.

"These characteristics are normally found only in very expensive lasers, not in mass-produced VCSELs," said Kent D. Choquette, an Illinois professor of electrical and computer engineering and a researcher at the university’s Micro and Nanotechnology Laboratory. "By embedding a two-dimensional photonic crystal into the top face of a VCSEL, however, we can accurately design and control the device’s mode characteristics."


Choquette and his colleagues -- Illinois graduate students Aaron J. Danner and James J. Raftery Jr., and scientist Noriyuki Yokouchi at the Furukawa Electric Co. in Yokohama, Japan -- will report their findings in the Feb. 16 issue of the journal Applied Physics Letters.

The two-dimensional photonic crystal, created by drilling holes in the semiconductor surface, introduces a periodic change in the index of refraction, Choquette said. The holes represent regions of low refractive index, surrounded by semiconductor material where the index is higher. A particular combination of refractive indices will produce a single-mode waveguide that permits only one transverse wave of the laser beam to propagate.

"Our photonic crystal consists of a triangular array of circular holes that have been etched into the top of a VCSEL," Choquette said. "Because the index variation has to be on the length scale of light, the periodicity of the holes must be on the order of several hundred nanometers."

To create such a precise array of holes, the researchers first lithographically define the desired pattern into a silicon dioxide mask layer on the semiconductor surface using focused-ion beam etching. The holes are then bored into the semiconductor material using inductively coupled plasma etching.

"By selectively varying parameters such as depth, diameter and spacing of the holes, we can control the modal characteristics of the laser," Choquette said. "This means we can accurately design and fabricate single-mode VCSELs for high-performance optical communication systems."

The next step, he said, is to push VCSEL performance toward higher power by considering designs that are much larger in diameter.

"Looking beyond that, we also have fundamental problems with high-speed data communication on our circuit boards and in our chips," Choquette said. "This is a technology that could serve as the foundation for a new way of looking at optical interconnects and photonic integrated circuits."


###
The National Science Foundation and Defense Advanced Research Projects Agency funded the work.

James E. Kloeppel | UIUC
Further information:
http://www.news.uiuc.edu/news/04/0210crystals.html

More articles from Physics and Astronomy:

nachricht Electronic evidence of non-Fermi liquid behaviors in an iron-based superconductor
11.12.2018 | Science China Press

nachricht Physicists edge closer to controlling chemical reactions
11.12.2018 | Moscow Institute of Physics and Technology

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: Topological material switched off and on for the first time

Key advance for future topological transistors

Over the last decade, there has been much excitement about the discovery, recognised by the Nobel Prize in Physics only two years ago, that there are two types...

Im Focus: Researchers develop method to transfer entire 2D circuits to any smooth surface

What if a sensor sensing a thing could be part of the thing itself? Rice University engineers believe they have a two-dimensional solution to do just that.

Rice engineers led by materials scientists Pulickel Ajayan and Jun Lou have developed a method to make atom-flat sensors that seamlessly integrate with devices...

Im Focus: Three components on one chip

Scientists at the University of Stuttgart and the Karlsruhe Institute of Technology (KIT) succeed in important further development on the way to quantum Computers.

Quantum computers one day should be able to solve certain computing problems much faster than a classical computer. One of the most promising approaches is...

Im Focus: Substitute for rare earth metal oxides

New Project SNAPSTER: Novel luminescent materials by encapsulating phosphorescent metal clusters with organic liquid crystals

Nowadays energy conversion in lighting and optoelectronic devices requires the use of rare earth oxides.

Im Focus: A bit of a stretch... material that thickens as it's pulled

Scientists have discovered the first synthetic material that becomes thicker - at the molecular level - as it is stretched.

Researchers led by Dr Devesh Mistry from the University of Leeds discovered a new non-porous material that has unique and inherent "auxetic" stretching...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

New Plastics Economy Investor Forum - Meeting Point for Innovations

10.12.2018 | Event News

EGU 2019 meeting: Media registration now open

06.12.2018 | Event News

Expert Panel on the Future of HPC in Engineering

03.12.2018 | Event News

 
Latest News

Electronic evidence of non-Fermi liquid behaviors in an iron-based superconductor

11.12.2018 | Physics and Astronomy

Topological material switched off and on for the first time

11.12.2018 | Materials Sciences

NIST's antenna evaluation method could help boost 5G network capacity and cut costs

11.12.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>