A light source assembly (300) for emitting depolarized light, and comprising: at least one light source (312) configured to emit substantially polarized light; and a light depolarizer (318) arranged to receive light from the light source and comprising a high birefringence optical fiber having a longitudinal core and orthogonal birefringent axes having an angular displacement around the core that varies along the length of the fiber, wherein light emitted from the depolarizer comprises a plurality of polarization states.