Bill,..Re:.MEMS
More on the mirror technology from IEEE Spectrum.
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spectrum.ieee.org
Mirror, mirror
Microelectromechanical systems (MEMS) continue to move into mainstream applications. Of note is the growing use of tiny mirrors that can be moved by electrostatic forces. Micromirror technology was pioneered by Texas Instruments Inc., Dallas, for use in projection displays [see Spectrum, November 1993, pp. 27-31]. But micromirrors may soon be found in telescopes located in outer space, while their earthbound cousins form a key element of the WaveStar LambdaRouter recently announced by Lucent Technologies. The all-optical wavelength router switches traffic in an optical network at the optical wavelength level--it is not a packet router, which looks at individual packets and routes them to their destinations [see "Communications"].
In the router, optical signals are transferred from fiber to fiber without being converted into and from electrical signals, as is the practice today. Instead, the signals bounce off an array of 256 freely and independently rotating mirrors. The mirrors are circular--less than a millimeter in diameter--and supported in a gimbal mount, which lets them rotate about two axes. To be specific, the mirror can rotate about hinges attached to a surrounding ring, which can rotate about hinges attached to yet another concentric ring. Each mirror is illuminated by a single wavelength and is tilted by electrostatic forces so that the individual wavelength can be passed on to one of 256 input and output fibers. This approach saves time and means that network traffic can be directed 16 times faster and with a hundredth the power needed with electrical switches. Standard micromachining techniques suffice to fabricate each array on a single substrate [see "The broad sweep of integrated microsystems," Spectrum, December 1998, pp. 24-33].
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But this still sounds electromechanical. The optical switches by Nanovation sound more 'solid state'? <g>
nanovation.com
nanovation.com
Cheers,
Lee
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