Fourth-order cascaded Raman shift in a birefringence ZBLAN fluoride fiber

Abstract We investigate fourth-order cascaded Raman shift in a birefringence ZrF 4 –BaF 2 –LaF 3 –AlF 3 –NaF (ZBLAN) fluoride fiber, which is the first demonstration of cascaded Raman shift in fluoride fibers. The pump source is a commercially available 1064 nm picosecond fiber laser. At the average pump power of ∼7 W, fourth-order cascaded Raman shift is observed if the pump pulse is polarized to the slow axis, and third-order cascaded Raman shift is obtained if the pump pulse is polarized to the fast axis. The Raman shift generation is simulated by the generalized nonlinear Schrodinger equation (GNLSE), and the results are in good agreement with the experiments.