Disclosed is an optical fiber formed from a preform that includes a clad component and a core component. The core component includes one or more precursor core materials. The precursor core materials and the clad materials are selected such that that the photoelastic constants of at least one precursor core material and the clad material are of opposite sign resulting in a final glass optical fiber of tailored Brillouin performance. The clad material may include an oxide glass having a positive photoelastic constant and the core component may include a precursor core material that has a negative photoelastic constant. During formation, the precursor core material can melt and interact with clad material that precipitates into the core to form a glass of at least one tailored Brillouin property, such as very low Brillouin gain
