Cover Story

NATURAL SELECTION-IT IS NATURE'S RUTHLESS TOOL FOR OPTIMIZING SYSTEMS, YET ONE THAT ENCOURAGES DIVERSITY. AS ENGINEERS WE CAN STUDY THE STRUCTURE OF NATURAL SYSTEMS FOR CLUES THAT MAY LEAD TO THE OPTIMIZATION OF MAN-MADE SYSTEMS. ONE OF... more>>

Features

Soliton Transmission Speeds Greatly Multiplied By Sliding-Frequency Guiding Filters

The invention of the erbium fiber amplifier just a half-dozen years ago1,2 paved the way for development of wide-band, "all-optical," long distance fiber transmission systems. There were two principal incentives for the development of these systems. First, the huge bandwidth of the optical amplifiers would limit neither the fundamental bit rate nor the potential for extensive wavelength-division-multiplexing (WDM). Second, save for the amplifiers themselves, the system would be strictly passive, so that the many expensive, rate-limiting, active components of electronic regeneration, with their potential for failure, would be eliminated. It was also important that most other properties. more>>