b$.$ Consider a long single$-$mode optical fiber with core diameter of $6\backslash$mu m having an attenuation of $0\mathrm{.}5$ dB $/$ km when operating at a wavelength of $1\mathrm{.}3\backslash$mu m and the laser source bandwidth is $600$ MHz$.$ i$.$ Compare the threshold optical powers for stimulated Brillouin scattering and Raman scattering within the fiber at the wavelength specified and provide your judgment based on the value obtained. $($CO$2$; PO$2-4$ Marks$)$ ii$.$ Suggest a way of avoiding the losses introduced by nonlinear scattering. $($CO$2$; PO$2-3$ Marks$)$