SINGLE MODE OPTICAL FIBER WITH GROOVE HAVING DIFFERENT REFRACTIVE INDEX

摘要

PURPOSE:To reduce the leakage of light and to decrease the bending and micropending loss by attaching a concentric layer with lower refractive index than that of the core of an optical fiber and a clad between the core and clad. CONSTITUTION:A concentric intermediate layer 3 whose essential component is quartz with lower refractive index than that of a core 1 whose essential component is quartz glass and a clad 2 is fitted between the core 1 and clad 2. After separating a silicon dioxide film including about 1mol% fluorine on the inner surface of a quartz glass tube whose outer diameter is 14mm. and inner diameter is 12mm. by vaper phase reaction and moreover separating a film including about 5mol% germanium dioxide on the inner surface of the silicon dioxide film, these films are heated at 1,700 deg.C and wire-drawn at 2,000 deg.C to obtain a single mode optical fiber with a groove having a different refractive index. Thus, light leakage is reduced and bending loss and micropending loss are decreased.