In most distributed Brillouin sensing systems, it is crucial to keep the long-term stability of the electro-optic modulator (EOM) operating point. The dither-tone based bias control methods are widely adopted in this kind of systems for its robustness and reliability, but the low frequency dither tone (a few kilohertz) added into the dc bias port of the EOM may have a detrimental impact on the sensing performance of the Brillouin sensing system. Experimental results show that the dither frequency should not be set around quarter of the pulse repetition rate or its multiples, and the employed dither amplitude should be in the range of 0.003V_π to 0.015V_π (V_π is the RF half-wave voltage of the EOM), in order to overcome the limitation of dither tone based bias control techniques in BOTDA systems. These results will provide guidelines to improve the performance of the Brillouin sensing systems using dither-based EOM bias control method.

Date Published: 8 October 2015
PDF: 6 pages
Proc. SPIE 9679, AOPC 2015: Optical Fiber Sensors and Applications, 967911 (8 October 2015); doi: 10.1117/12.2200973

Published in SPIE Proceedings Vol. 9679:
AOPC 2015: Optical Fiber Sensors and Applications
Yanbiao Liao; Weixu Zhang; Desheng Jiang; Wei Wang; Gilberto Brambilla, Editor(s)