3-mm Recognition Capability of Forward Stimulated Brillouin Scattering Measurement by Brillouin Selective Sideband Amplification

Forward stimulated Brillouin scattering (F-SBS) has gained rapid development due to its innovative capabilities such as detecting the mechanical properties of materials surrounding the optical fibers. However, the capability of current schemes to measure ultra-weak F-SBS signals remains inadequate, which is fatal for sensors with high spatial recognition capability and precise measurement. Here, we proposed an enhanced detection scheme of F-SBS based on Brillouin selective sideband amplification. The transverse acoustic waves (TAWs) are excited and impose phase modulation on the probe wave. Then, one of the sidebands of phase modulation is amplified via backward stimulated Brillouin scattering (B-SBS). The demodulation efficiency is related to the B-SBS gain, which is expected to be at least 3 orders of magnitude higher than current schemes. In the experiment, F-SBS on a 3-mm etched segment over a standard single-mode fiber was recognized for demonstrating the spatial recognition capability, along with temperature sensing. To the best of our knowledge, this is the most advanced spatial recognition capability for F-SBS measurement currently reported.