Singular hyperbolicity for transitive attractors with singular points of 3-dimensional <Emphasis Type="Italic">C</Emphasis><Superscript>2</Superscript>-flows

In the context of C^r-flows on 3-manifolds (r ≥ 1), the notion of singular hyperbolicity, inspired on the Lorenz Attractor, is the right generalization of hyperbolicity (in the sense of Smale) for C¹-robustly transitive sets with singularities. We estabish conditions (on the associated linear Poincaré flow and on the nature of the singular set) under which a transitive attractor with singularities of a C²-flow on a 3-manifold is singular hyperbolic.     

All-optical 2R regeneration using passive saturable absorption

This paper reports on the regenerative properties and efficiency of an all-optical 2R regenerator based on a tandem of saturable absorber (SA) chips. A new SA structure allowing mark level equalization, which is a complement to the function of extinction ratio enhancement of the classical SA structure, is described. The experimental results at 42.6 Gbit/s show that amplitude fluctuations on both low and high power levels are significantly reduced with the SA tandem regenerator, and the system margin improvements in terms of receiver sensitivity and Q factor are obtained.