Laser-induced ultraviolet absorption and refractive index changes in Ge–B–SiO 2 planar waveguides by inductively coupled plasma-enhanced chemical vapor deposition

Abstract

We report on the observation of a strong KrF laser-induced ultraviolet absorption and refractive index changes from germanium-doped and boron co-doped silica (Ge–B–SiO 2) planar waveguides. The Ge–B–SiO 2 planar waveguides on a pure silica substrate with optical propagation-loss of ∼0.2 dB/cm at 1.55 μm have been deposited by a new approach namely inductively coupled plasma-enhanced chemical vapor deposition. We have noticed that samples when annealed at 1000 °C are exhibiting very limited ultraviolet absorption at ∼240 nm, however, an enhancement has been found with the ∼240 nm absorption band due to the hydrogenation treatments. KrF laser has partially bleached the absorption at ∼240 nm and that has generated new paramagnetic site such as GeE ′ centers with significant changes in the ultraviolet related absorption and refractive index of Ge–B–SiO 2 waveguides.