Article Abstracts | November 2006
The complete article appears in the November 2006 issue of Photonics Spectra. If you do not have a copy of this issue,
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Wavelength Selective Switches for Fiber Optic Telecommunications
As these switches become increasingly popular, it is important to understand how they work and where the technology is headed.
by Michael Nagy, Olympus Microsystems America, and Sorin Tibuleac, ADVA Optical Networking
Dense wavelength division multiplexing (DWDM) systems have become the standard technology in high-capacity telecommunications networks ranging in distance from a few kilometers to thousands of kilometers. They combine multiple wavelengths on a single optical fiber, with each wavelength having data modulation rates up to 10 Gb/s. The newest technology pushes the rate up to 40 Gb/s. Each wavelength can carry any communications protocol containing Internet data, video or telephony information.
At the beginning and end of an optical link are “on” and “off” ramps, where information is converted from electrical to optical signals (at the on ramp) or vice versa (at the off ramp). Devices called “optical add/drop multiplexers” perform the functions of the on and off ramps by allowing some wavelengths to pass through toward other network nodes and others to be terminated at the local node...
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