For Brillouin optical time-domain analysis(BOTDA) based on distributed Brillouin amplification(DBA), constant Brillouin response achieved by the exponentially variable bandwidth/intensity pump modulation suffers from ...For Brillouin optical time-domain analysis(BOTDA) based on distributed Brillouin amplification(DBA), constant Brillouin response achieved by the exponentially variable bandwidth/intensity pump modulation suffers from the much lower pumping efficiency for long-range sensing, which counterbalances the merit of DBA. In this Letter, pump modulation by multiple constant bandwidths was proposed and demonstrated. The ～98.9 km sensing with ～5 m spatial resolution and no use of optical pulse coding(OPC) was achieved by ～8 dBm Brillouin pump, which is lower by ～9 dB in theory by comparison with exponentially increased bandwidth modulation.Compared with traditional DBA-BOTDA, signal-to-noise ratio(SNR) enhancement with >4.6 dB was obtained. The flattened standard deviation(STD) of Brillouin frequency shift(BFS)(less than ～2 MHz) along the whole fiber was demonstrated.展开更多
The impacts of Brillouin pump depletion and nonlinear amplification in coded long-range Brillouin optical time-domain analysis （BOTDA） based on distributed Brillouin amplification （DBA） were studied. The error of ...The impacts of Brillouin pump depletion and nonlinear amplification in coded long-range Brillouin optical time-domain analysis （BOTDA） based on distributed Brillouin amplification （DBA） were studied. The error of Brillouin frequency shift （BFS） due to Brillouin pump depletion was compared for DBA-BOTDA using non-cyclic and cyclic coding. For non-cyclic coding, significant over- and under-shoots of BFS were found in the range with larger BFS variation, such as hot spot. The impact of Brillouin pump depletion can be reduced considerably by cyclic coding. Furthermore, to compensate the BFS error due to nonlinear amplification, a simple and effective log linearization was oroDosed and demonstrated.展开更多
基金supported by the National Natural Science Foundation of China(NSFC)(No.61205079)the Scientific Research Fund of Sichuan Provincial Education Department(No.18ZA0401)
文摘For Brillouin optical time-domain analysis(BOTDA) based on distributed Brillouin amplification(DBA), constant Brillouin response achieved by the exponentially variable bandwidth/intensity pump modulation suffers from the much lower pumping efficiency for long-range sensing, which counterbalances the merit of DBA. In this Letter, pump modulation by multiple constant bandwidths was proposed and demonstrated. The ～98.9 km sensing with ～5 m spatial resolution and no use of optical pulse coding(OPC) was achieved by ～8 dBm Brillouin pump, which is lower by ～9 dB in theory by comparison with exponentially increased bandwidth modulation.Compared with traditional DBA-BOTDA, signal-to-noise ratio(SNR) enhancement with >4.6 dB was obtained. The flattened standard deviation(STD) of Brillouin frequency shift(BFS)(less than ～2 MHz) along the whole fiber was demonstrated.
基金supported by the National Natural Science Foundation of China(NSFC)(No.61205079)the Scientific Research Fund of Sichuan Provincial Education Department(No.18ZA0401)the Open Experimental Programs of Sichuan Normal University(No.KFSY2017083)
文摘The impacts of Brillouin pump depletion and nonlinear amplification in coded long-range Brillouin optical time-domain analysis （BOTDA） based on distributed Brillouin amplification （DBA） were studied. The error of Brillouin frequency shift （BFS） due to Brillouin pump depletion was compared for DBA-BOTDA using non-cyclic and cyclic coding. For non-cyclic coding, significant over- and under-shoots of BFS were found in the range with larger BFS variation, such as hot spot. The impact of Brillouin pump depletion can be reduced considerably by cyclic coding. Furthermore, to compensate the BFS error due to nonlinear amplification, a simple and effective log linearization was oroDosed and demonstrated.
