March 2003

The Evolution of SONET/SDH Over WDM

Paul Bonenfant

Among the promising innovations moving to market: a fully automated optical layer and fully integrated synchronous optical network/synchronous digital hierarchy over wavelength division multiplexing.

Fiber to the Home Why "the Last Mile" Is Truly the Hardest

After decades of talk, fiber-to-the-home installations are now a reality in some U.S. communities. The key players are not giant phone or cable-TV companies but small public utilities, rural phone cooperatives and upscale housing developers.

Novel Fiber Lasers and Applications

Under impetus from the telecom market, new types of fiber lasers have been developed and deployed. On the horizon are new applications that demand transmission at different wavelengths and higher output powers.

Tunable MEMS Devices for Optical Networks

Dynamic wavelength provisioning is the greatest benefit associated with the use of tunable lasers and filters in transparent networks. A prerequisite is the availability of tunable devices that meet the rigorous performance requirements of fixed wavelength transceivers—at comparable costs.

The Invention of "Light Writing," or How the Cosmos Came to Draw Itself

In the nineteenth century, scientists began to explore ways of “fixing” the image thrown by a lens. The invention of the daguerreotype was followed by the appearance of less expensive techniques, including the tintype. The photoheliograph, a device for taking telescopic photographs of the sun, was unveiled in 1854.

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