Interference of FSBS and Kerr effect in a standard highly nonlinear fiber

We observe efficient forward stimulated Brillouin scattering (FSBS) in a standard 2-km highly-nonlinear optical fiber (NHLF), where we see multiple resonance peaks between 425 MHz to 1.1 GHz. The most efficient acousto-optical coupling appears for the 20th radially-guided acoustic mode at 933.8 MHz, which has maximum spatial overlapping with the tightly confined optical mode in the NHLF fiber. A large gain coefficient of 34.7 W^-1 is obtained at this resonance when pumped with a 8 mW continuous-wave (cw) beam at 1550 nm, and an enhanced gain of 57.6 is obtained by using a pulsed pump beam at 80 mW. Interference between the FSBS process and the Kerr effect is observed to enhance the resonance and cause asymmetric profile for the observed resonances.