A selffocusing spectral splitter is a precision optical component designed specifically for connecting and separating divergent light beams. It is typically used in passive optical devices for fiber optic connections to effectively collimate light beams and enhance the performance of. So far, solar spectral splitters suffered from a strong angle dependency, which caused degradation in performance at the slightest deviation from normal incidence. a laser beam) into two (or sometimes more) beams, which may or may not have the same optical power (radiant flux).