Bandstructure engineering of intersubband optical transitions has led to a new class of quantum cascade lasers (QCL) that simultaneously emit multiple wavelengths by suitable tailoring of the gain spectrum of identical cascaded active regions or by cascading of different active regions. Using the larrer approach the first super continuum semiconductor laser has been demonstrated. Bidirectional QCLs as well as preliminary results on intracavity nonlinear optical generation will be discussed.

© 2002 Optical Society of America

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