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For decades, silicon was not considered a favorable material for manipulating light. Ray Chen, Professor of Electrical Engineering at The University of Texas at Austin and Wei Jiang at Omega Optics (Austin, TX) recently invented a compact silicon modulator that can make a laser beam blink by driving a small electric current into the silicon chip cyclically. Exploiting fine silicon structures smaller than one-thousandth of the diameter of human hair, this invention helps us one big step closer to a long dream to put working optics on silicon chips. This provides a power consumption at least one order of magnitude smaller than existing devices while the active device length is one order smaller than the state of the art.
Such a silicon nanophotonic modulator is a milestone of optical interconnection technology. With the presence of silicon, optics won't be the same. And electronics will benefit from it enormously. For example, future computers that are thousands of times faster need to relay overwhelmingly large-volume data on a silicon chip. The current relaying scheme goes through electricity, which is slow. Optics is the way out. And the silicon modulator developed by Omega Optics is an essential part of it.
The silicon modulator could be used to relay data or information because the blinking of light can be controlled by the electric current injected into the silicon chip. By varying the current, one can change the blinking rate, interval, or the intensity of light to produce different patterns. Each pattern could be assigned a meaning. As light blinks along the way, information is carried around the silicon chip.
The goal is to use a minimum amount of electric current to produce the blinking effect. Silicon microprocessor chips are plagued by excess heating due to high power consumption, and optics can address that. By driving the structure dimensions toward nanoscale, the optical modulator slows down light significantly. This allows light stay longer in the device and has more time to interact with the alternating electrical current signal. The enhanced interaction in turn reduces the amount of current needed to produce the modulation, and more significantly, reduces the device dimension (or, technically speaking, interaction length) drastically. The reduction could be as much as two orders of magnitude, compared to common specs of integrated Mach-Zehnder modulators.
The work is supported by Air Force Office of Scientific Research, through an STTR program awarded to Omega Optics and the University of Texas at Austin.
Related News Link:
EE Times:
http://eetimes.com/news/latest/showArticle.jhtml?articleID=175800181
OE Magazine:
http://oemagazine.com/newscast/2005/112505_newscast01.html
SPIE News Archive (Week 47, News 2005):
http://spie.org/AboutSPIE/index.cfm?fuseaction=news&year=2005&month=November
NASA Photonics Tech Briefs:
http://www.nasatech.com/Briefs/Apr06/5656_201.html
Laser Focus World:
http://lfw.pennnet.com/articles/article_display.cfm?article_id=250405
Professor and former student maneuver light on silicon
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