Photosensitivity of sol-gel derived inorganic xB(2)O(3) : 20GeO(2) : (80-x) SiO2 system with various boron concentrations

摘要

Optical properties of sol-gel synthesized boron co-doped germanosilicate(xB(2)O(3) : 20GeO(2) : (80-x) SiO2) thin films (single layer) were investigated by varying the molar concentration of B2O3 for x = 5, 10 and 20 under various annealing temperatures, ranging from 500 to 1000 degrees C. Densification of the thin film was found to be influenced by the concentration of boron under various annealing temperatures. Iterative deposition of the dense xB(2)O(3) : 20GeO(2) : (80-x) SiO2 (for x = 5, 10 and 20) thin film was used to fabricate a few micrometre thick single-mode slab waveguides at 1.55 mu m. Refractive indices and the propagation loss values of the waveguide samples were determined by using the prism-coupler technique. Under ultra-violet illumination, the refractive index change (Delta n) of the xB(2)O(3) : 20GeO2 : (80-x) SiO2 increases with increasing B2O3 concentration, for both transverse electric and transverse magnetic. The values of Delta n(TE) are similar to 0.009, similar to 0.012 and similar to 0.014, for x = 5, 10 and 20, respectively. The high values of Delta n, which increase with the B2O3 concentration are probably caused by the larger stress present in the boron doped films.