Lead-containing fluoride glass, optical fiber and process for producing it

摘要

Lead-containing fluoride glass comprises 50-70 mol % of ZrF4, 3-5 mol % of LaF3, 0.1-3 mol % of YF3, and 2-15 mol % of NaF and/or LiF and/or CsF, where LaF3+YF3=4.5-6 mol %, and further comprises lead. An optical fiber comprises a core made of the lead-containing fluoride glass and a cladding surrounding the core. A process for producing an optical fiber comprises forming a base material for a core of the lead-containing fluoride glass, forming a base material for a cladding of fluoride glass containing 30-60 mol % of HfF4, and drawing the base materials into an optical fiber at a drawing temperature of 315-340 DEG C.