Nonlinear chalcogenide fiber

Chalcogenide fibers used in our experiments are formed from very high purity materials in order to achieve single mode fibers with relatively low losses of approximately 0.5 dB/m. All-optical processing devices typically require a nonlinear phase shift /spl Delta//spl Phi/=/spl gamma/PL=/spl pi/ radians for an optical pulse propagating with a peak power P through a fiber length L. The nonlinear fiber response is measured by /spl gamma/=2/spl pi/n/sub 2///spl lambda/A/sub eff/, where n/sub 2/ is the nonlinear Kerr coefficient, /spl lambda/ is the wavelength and A/sub eff/ is the effective core area. Our experiments demonstrate /spl gamma/=1500 W/sup -1/km/sup -1/ for core areas of 50 /spl mu/m/sup 2/. We measure strong self-phase modulation in As-Se fibers formed from high purity materials. Raman gains near 40% were measured using a CW pump power near 200 mW in a 70 cm long fiber with a core area of 50 /spl mu/m/sup 2/. Applications of these fibers to Raman and parametric amplifiers as well as optical processing devices will be discussed.