Backscattered lightwaves from an optical fibre are used to realise distributed fibre optic sensing(DFOS)systems for measuring various parameters.Rayleigh,Brillouin,and Raman backscattering provide different sensitivit...Backscattered lightwaves from an optical fibre are used to realise distributed fibre optic sensing(DFOS)systems for measuring various parameters.Rayleigh,Brillouin,and Raman backscattering provide different sensitivities to different measurands and have garnered the attention of researchers.A system combining the three principles above can effectively separate the measured strain and temperature completely as well as provide measurements of both dynamic and static parameters.However,the combined system is extremely complicated if the three systems are independent of each other.Hence,we propose a single-end hybrid DFOS system that uses two successive pulses to realise the Brillouin amplification of Rayleigh backscattering lightwaves for combining Rayleigh and Brillouin systems.A 3-bit pulse-coding method is employed to demodulate the Raman scattering of the two pulses to integrate Raman optical time-domain reflectometry into the hybrid system.Using this hybrid scheme,a simultaneous measurement of multiple parameters is realised,and a favourable measurement accuracy is achieved.展开更多
基金funding from the National Natural Science Foundation of China(NSFC)under grant numbers 61735015,62275151the Major Key Project of PCL.
文摘Backscattered lightwaves from an optical fibre are used to realise distributed fibre optic sensing(DFOS)systems for measuring various parameters.Rayleigh,Brillouin,and Raman backscattering provide different sensitivities to different measurands and have garnered the attention of researchers.A system combining the three principles above can effectively separate the measured strain and temperature completely as well as provide measurements of both dynamic and static parameters.However,the combined system is extremely complicated if the three systems are independent of each other.Hence,we propose a single-end hybrid DFOS system that uses two successive pulses to realise the Brillouin amplification of Rayleigh backscattering lightwaves for combining Rayleigh and Brillouin systems.A 3-bit pulse-coding method is employed to demodulate the Raman scattering of the two pulses to integrate Raman optical time-domain reflectometry into the hybrid system.Using this hybrid scheme,a simultaneous measurement of multiple parameters is realised,and a favourable measurement accuracy is achieved.
