Golay-Differential Pulse Hybrid Coding Technology Based on Brillouin Optical Time Domain Analysis Sensors

A distributed Brillouin dam health monitoring scheme based on differential pulse pairs

“…Moreover, in the detection of BOTDA, the Stokes light variation is the sensing signal of BOTDA. When the noise level of the detector remains constant, the wider the width of the pulse light, the higher the signal-to-noise ratio of BOTDA [9] .…”

“…The spatial resolution of traditional Raman and Brillouin distributed fiber optic sensing systems corresponds to the pulse width of the pump pulse light, and it is usually necessary to reduce the pulse width of the pump light to improve spatial resolution. When the spatial resolution reaches 1m, this method is limited by the following limitations when continuing to improve spatial resolution [2] : First, due to the influence of phonon lifetime (~10ns, quartz fiber), the gain of Brillouin *yangxiaojun0707@163.com signal increases exponential type with the increase of pump pulse width. If the pump pulse width is less than the phonon lifetime, the signal to noise ratio of Brillouin signal is weak because the acoustic field has not reached a steady state, which reduces the measurement accuracy and measurement length of the system; Secondly, due to the influence of Brillouin gain spectrum broadening, as the pulse width of the pump pulse light decreases, especially below 10ns, the spectrum broadening phenomenon of the pump pulse light is very obvious, which will reduce the signal-to-noise ratio of the Brillouin signal.…”