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MIT Electrical Engineering and Computer Science
EECS Event |
Tuesday, April 24, 2001
2:00 PM (refreshments 1:45)
Grier Room, Room 34-401B
EECS Special Seminar
Abstract
As data communication links are continuously being pushed to higher speeds and larger bandwidths, all-optical devices are becoming key elements to sustain this development. In this talk, I will discuss all-optical wavelength conversion as a prime example for the synthesis of semiconductor physics, optics and practical application. In the first part, quantum interference and its dramatic effects on the optical properties of a medium such as electromagnetically induced transparency (EIT) or slow light is described. Specifically, I will show how EIT can be used to realize wavelength conversion and optical switching by taking advantage of either the linear or nonlinear susceptibility. Examples for both approaches are presented and evaluated for their potential to operate at high bandwidths. In the second part of the talk, quantum well intersubband transitions are introduced as a new platform for ultrafast all-optical devices at fiber-optic communication wavelengths. By using bandgap engineering, it is possible to realize quantum wells that exhibit optical transitions in the conduction band around 1.55 µm. These transitions have very promising high-speed properties and a number of advantages over conventional interband approaches. I will discuss approaches in different material systems, along with absorption measurements and design strategies for such wavelength converters. .