A novel double-clad As<sub>2</sub>Se<sub>3</sub> chalcogenide photonic crystal fiber is proposed and the slow light via stimulated Brillouin scattering is theoretically investigated. The Brillouin gain spectrum by taking into account the high-order acoustic modes is analyzed. The simulated results indicate that the slow light can be tuned by varying the air filling fraction in the inner cladding. The time delay upto 1120ns can be achieved with 1-m-long fiber when pumped with 10mW. But these features of slow light are less affected with the change of the air filling fraction in the outer cladding.
Intermodal Brillouin frequency shift and Brillouin gain spectrum in few-mode fibers are investigated by full vectorial finite element method, and the influences of pump power on the time delay and pulse broadening factor are also simulated. The simulation results show that Brillouin gain of intermodal stimulated Brillouin scattering varies with different modes pairs. Time delay increases with increasing of pump power. Pulse broadening factors decrease with the input signal pulse width but increase with the input pump power. Optimized results show that time delay of <i>LP</i><sub>01</sub> - <i>LP</i><sub>01</sub>mode pair is 213.2ns, and the corresponding pulse broadening factors is 1.126.