Contents I. Introduction
The use of parametric processes in materials presenting a third order nonlinearity is a well-known technique for the demonstration of optical signal processing functionalities, including wavelength conversion, parametric amplification, optical phase conjugation and regeneration [1]. Such demonstrations have traditionally been performed using highly nonlinear optical fibers (HNLFs) as the nonlinear interaction medium. However, due to their relatively weak nonlinearity, HNLF lengths of the order of several hundred meters are typically required. In such fibers, the efficiency of parametric processes is often limited by stimulated Brillouin scattering (SBS). Furthermore, longitudinal variations of the dispersion may affect the fulfillment of the phase matching condition, hence the parametric device bandwidth. Therefore, even though fiber modules can be made relatively compact, and in spite of the maturity of the HNLF technology, other nonlinear materials have been investigated over the past few years.
