Enhanced gain coefficient in Raman amplifier based on silicon nanocomposites.

Abstract: In this paper, silicon nanoparticles dispersed into a silica phase by sol–gel processing has been investigated by structural and nonlinear-optical characterization. The structural characterization has been performed by energy filtered and scanning transmission electron microscopy. A silicon nanoparticles mean radius of about 49nm and a nanoparticle density of about 1.62×10⁸ dots/cm² have been obtained. Regarding nonlinear optics characterization, the observation of stimulated Raman scattering and the realization of a Raman amplifier based on silicon nanocomposites are described. Using a 1427nm cw pump laser, amplification of Stokes signal, at 1542.2nm, up to 1.4dB/cm is demonstrated. A preliminary valuation of approximately a fivefold enhancement of the gain coefficient a significant reduction of threshold power are reported. Our findings have a potential interest for silicon-based Raman lasers. [Copyright &y& Elsevier]