Dual-laser Brillouin optical correlation-domain reflectometry

Abstract We develop a new configuration for Brillouin optical correlation-domain reflectometry (BOCDR), termed dual-laser BOCDR. This method enables distributed strain and temperature measurement by sweeping the relative phase between the frequency-modulated pump and reference laser outputs. During operation, we identify a unique 0 Hz Rayleigh noise caused by the interference between the Rayleigh scattered lights within a fiber under test (FUT). We demonstrate that this noise can be effectively suppressed by increasing the reference power while decreasing the Stokes power. Subsequently, we conduct distributed strain measurement along a 13 m-long FUT, observing Brillouin gain spectra at frequencies of as low as approximately 200 MHz.