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INTEGRATED CIRCUITS FOR DISPERSION COMPENSATION IN OPTICAL COMMUNICATION LINKS
21.1 MOTIVATION
Demand for highdata rates has motivated researchers to work on optical communication links in many applications. However, the most powerful computing and storage platforms we have today operate on electrical signals. The use of optical signals in a system that is predominantly electrical presents some challenges. Electrical links use copper wires and are advantageous in terms of cost but suffer from channel impairments such as skin effect and dielectric losses, especially at high frequencies. Crosstalk can be a major concern in closely spaced electrical links at high data rates. On the other hand, optical links employ optical fiber and are colloquially labeled an infinite bandwidth medium due to their low loss. Furthermore, relatively little noise is introduced along an optical fiber, and fibers can be bundled tightly together with much less crosstalk than copper wires. However, optical links mandate the use of expensive components to convert the signals between the electrical and optical domains, and their bandwidth is limited by the dispersive property of light. Dispersion occurs because the propagation delay of a light signal through an optical fiber depends on the wavelength of light and also on the light’s mode of propagation. Called dispersion, these impairments cause different portions of an optical pulse to ...
