ABSTRACT:

Stimulated Brillouin Scattering (SBS) is a fascinating nonlinear effect arising from the interaction of light with acoustic modes. In fibers, it therefore depends on both their propagation characteristics.  SBS is particularly interesting in microstructured fibers, in which this propagation can be controlled through the geometry of the fiber.  In this talk, we first give a general overview of the characteristics and properties of these relatively new fibers.  We then present our results on Stimulated Brillouin Scattering in these, showing in particular its strong polarization dependence and evidence for new acoustic modes. In the second part of the talk, we show how SBS can be used to slow down or accelerate light, with possible application to optical delay lines.  Finally, in the last part of the talk, we look at the propagation of light in multicore microstructured fibers, coupling between cores, the effect of polarization and what happens in the nonlinear regime.

BIOSKETCH:

Professor J.Toulouse received his PhD from Columbia University in Solid State Science in early 1982. After a two year postdoc, also at Columbia, studying very low temperature dielectric relaxations of irradiation defects in quartz, he joined the Physics Department at Lehigh in 1984. There, he began a study of Phase Transitions in disordered systems (mixed ferroelectrics and glasses) using a variety of techniques, including ultrasonics, Raman and neutron scattering. In 1996, after one and half year as a program director at NSF, he launched a new research program in nonlinear fiber optics at Lehigh (Stimulated Brillouin, Stimulated Raman etc.) in collaboration with colleagues at Lucent Technologies/Bell Laboratories, and soon after led a campus-wide initiative in Photonics that resulted in the creation of a new Center for Optical Technologies in 2001. In 2001-2002, he spent half a sabbatical year at Lucent Technologies (Holmdel) in the Advanced WDM Transmission group and the other half in the Optoelectronics group at the University of Bath (England), with the inventors of Photonic Crystal Fibers. His present research continues on two fronts, “Collective Phenomena in Disordered Ferroelectrics” and “Nonlinear Optical Effects in Novel Optical Fibers”.