BOTDR integrated with FBG sensor array for distributed strain measurement

A novel scheme using Brillouin optical time-domain reflectometry (BOTDR) and a fibre Bragg grating (FBG) sensor array simultaneously for long distance strain monitoring and accurate strain measurement of some key position is presented. BOTDR and FBG sensing parts are integrated into one system and a strain experiment is carried out. Experimental results show that the whole sensing system can work simultaneously without reference and achieve a strain distribution measurement as well as the point to point precise strain detection along a 20km sensing fibre. The strain resolution of the system is 50ε for BOTDR and 1ε for FBG, respectively, along 20km distance, while a spatial resolution of 2m can be achieved for the BOTDR part.