  We theoretically and numerically study the effects of thermal noise on pulses
in backwards Stimulated Brillouin Scattering (SBS). Using a combination of
stochastic calculus and numerical methods, we derive a theoretical model that
can be used to quantitatively predict noise measurements. We study how the
optical pulse configuration, including the input powers of the pump and Stokes
fields, pulse durations and interaction time, affects the noise in the output
Stokes field. We investigate the effects on the noise of the optical loss and
waveguide length, and we find that the signal-to-noise ratio can be
significantly improved, or reduced, for specific combinations of waveguide
properties and pulse parameters.

Optics