Raman-active optical fiber

2 22522222An optical fiber has a fiber core with a higher refractive index and a cladding surrounding the core with a lower refractive index. The fiber core is made of a multi-component oxide glass composition which consists of a glass-forming component and two Raman-active components. The glass former is SiOand the Raman active components are of LiO and NbO. The concentration of the glass former is between 30 and 90 mol % and of the Raman active components is up to 50 mol % in total. The composition may further include a glass-modifying component of alkaline such as LiO, NaO, KO, RbO, CsO or earth-alkaline such as BeO, MgO, CaO, SrO, BaO in a concentration of up to 40 mol %.