Investigating the Response of Distributed Fibre Optic Acoustic Sensing for Subsea Cable Motion Monitoring

摘要

A simultaneous Distributed Acoustic Sensing (DAS) and DistributedTemperature Sensing (DTS) system is presented. In DAS, perturbationsacross hundreds of metres of fibre are detected by the use of phasesensitiveOptical Time-Domain Reflectometry (OTDR) from Rayleighbackscattering caused by these perturbations. DTS relies on RamanOTDR in a similar fashion. The capabilities of the DAS system arepresented, showing detection limits on the order of sub Hz to kHz whileachieving spatial resolution on the order of metres. The ability todifferentiate between different types of perturbation including tapping,transient signals and smooth, strumming motion is demonstrated.