Analysis of spectroscopic properties of erbium doped Ta2O5-Al2O3-SiO2 optical fiber

An optical fiber with erbiusn ions doped in a Ta2O5-Al2O3SiO2 glass was fab ricated by modified chemical vapor deposition process along with an aerosol delivery technique. The effects of Ta2O5 on the spectroscopic properties o f the erbium ions in the glass host have been studied for an application in optical amplifiers. The ground state absorption spectra for the pump bands , I-4(15/2) --> I-4(11/2), I-4(15/2) --> I-4(9/2), I-4(15/2) --> F-4(9/2), and the gain band, I-4(15/2) --> I-4(13/2), of erbium ions were measured an d compared with those in aluminosilicate hosts. The excited state absorptio n I-4(13/2) --> H-2(11/2), S-4(3/2) around 800 nm and subsequent upconversi on fluorescence around 500 nm were also investigated Furthermore backward a mplified spontaneous emission in the 1.5 mu m region was measured for vario us pump wavelengths and intensities. Differences in spectroscopic features of erbium ions in these glasses compared with aluminosilicate glass contain ing erbium ions were attributed to Ta2O5 doping providing a lower local sym metry of crystal fields around erbium ions. (C) 1999 Elsevier Science B.V. All rights reserved.