An optical modulation method to suppress stimulated Brillouin scattering and the phase noise in a remote interferometric fiber sensing system

•The method is applied in interferometric fiber sensing systems.•The method suppresses SBS and its induced phase noise.•The method also avoids the linewidth broadening induced phase noise.•The method increases the input power and transmission length of the system.•The method keeps the system a low phase noise level with a higher input power.

A novel optical modulation method for stimulated Brillouin scattering (SBS) and the phase noise suppression in a remote interferometric fiber sensing system is proposed. Compared to the conventional phase modulation method to suppress SBS with only one phase modulation signal, another phase modulation signal with π shift is applied at the output end of the fiber, which converts the generated multi-frequency light to single-frequency light. Therefore the method can suppress not only SBS but also the phase noise induced by linewidth broadening owing to the first phase modulation. As a result, the method can keep the system a low phase noise level with a higher input power, which overcomes the conventional drawback of linewidth broadening. The results show a good reference to the design of remote interferometric fiber sensing systems.