Brillouin Gain Reduction Via B $_{2}$ O $_{3}$ Doping

We present both modeling results and experimental data demonstrating that B₂O₃ (boric oxide) can be used as an effective SBS-suppressive optical fiber codopant due to a very large acoustic damping coefficient. A Ge-containing fiber with ~6 wt% B₂O₃ at room temperature has a Brillouin gain coefficient more than 4 dB lower than that of standard Ge-doped SMF. These B-doped fibers, unlike standard Ge-doped SMF, have Brillouin spectra that broaden with increasing fiber temperature. Modeling parameters (acoustic velocity, spectral width, etc.) for bulk B₂O₃ based on a fit-to-data are provided. Modeling results for the B-Ge-Si oxide system indicate that the bulk material gain falls below 0.5×10^-11 m/W at 1534 nm near the 1B₂O₃:4SiO₂ molar composition.