Bi 2 O 3 -based glass for S-band amplification

Abstract

Bi<SUB>2</SUB>O<SUB>3</SUB>-based thulium (Tm<SUP>3+</SUP>) doped glass fiber (Bi-TDF) for S-band amplification was investigated. Tm<SUP>3+</SUP> was doped in Bi<SUB>2</SUB>O<SUB>3</SUB>-SiO<SUB>2</SUB> based glass and melted using a conventional method. Emission spectra of the <SUP>3</SUP>H<SUB>4</SUB> - <SUP>3</SUP>F<SUB>4</SUB> were measured with pumping at a wavelength of 792 nm using laser diode (LD). Full width of half maximum (FWHM) of the emission is 1.4 times and 1.1 times broader than that of fluoride glass and tellurite glass, respectively. Moreover, the emission peak shifted towards longer wavelength as compared with fluoride and tellurite glasses. Single mode Bi-TDFs with Tm<SUP>3+</SUP> concentrations of 2000 ppm, 3900 ppm and 6000 ppm were fabricated and evaluated with fusion splicing to SiO2 fibers. Gain profiles were measured with bi-directional pumping using 1047 nm Yb fiber lasers. The gain-peaks observed around 1470 nm shifted towards longer wavelength with increasing Tm<SUP>3+</SUP> concentration. Gain properties of Bi-TDF were improved by additional pumping at the wavelength of 1560 nm with Tm<SUP>3+</SUP> concentrations of 2000 ppm and 3900 ppm. A maximum gain over 10 dB of Bi-TDF was obtained using a fusion spliceable Bi-TDF with a length of only 100 cm.