Optical devices based on vertical microcavities offer an easy access to optical signals, propagated either in free space or in optical fibres, which presents a serious advantage when cost-related packaging issues are considered. Thanks to the enhanced nonlinear optical properties of excitonic transitions in III-V semiconductor quantum wells, it is possible to obtain saturable absorbers with a low saturation threshold power. They may exhibit a fast relaxation (down to the sub-picosecond time scale) through the introduction of non-radiative recombination centres, which can be incorporated during the epitaxial growth, or after the growth via ionic irradiation.

 

We shall present some recent results obtained through this approach for two types of applications

-          all-optical regeneration of high bit rate telecommunication signals

-          a ps-range optical pulse source at 1.55 µm wavelength based on the association of a vertical external cavity surface emitting laser (VECSEL) and a semiconductor saturable absorber mirror (SESAM)

Jean-Louis Oudar graduated from Ecole Polytechnique, Paris, in 1971 and received the Doctorate es-Sciences degree in Physics from the University of Paris in 1977. Since joining the Centre National d'Etudes des Telecommunications (CNET), he has worked on nonlinear optical phenomena in condensed matter: studying the enhanced optical nonlinearities of organic compounds, he developed the basis of a molecular engineering approach for nonlinear organic materials, an internationally recognised pioneering work. In 1979 he spent a year as a visiting scientist at the Physics Department of Berkeley University, where he worked on new techniques of nonlinear spectroscopy based on four-wave mixing. Then at CNET and France Telecom R&D, his research has been conducted on the ultrafast dynamic nonlinearities of III-V semiconductor microstructures, quantum optics of microcavities, and the development of optical bistable and switching devices. In 2000, he joined the newly created Laboratory for Photonics and Nanostructures of the Centre National de la Recherche Scientifique (CNRS-LPN), where he is currently leading the Photonic Devices for Telecommunications group. His present research interests include fast saturable absorber nanophotonic devices for all-optical regeneration, semiconductor light sources for optofluidic systems, short pulse generation and mode-locking phenomena in semiconductor lasers, including 1.55µm wavelength vertical external cavity surface emitting lasers.