Bragg grating in a two-mode optical fibre for sensing applications

Abstract The effects of writing a Bragg grating in a two-mode fibre used for acoustic detection are investigated. The advantages of such a grating, acting as both partial reflector and modal filter, are discussed with reference to a new quasi-distributed optical-fibre sensing system. It is envisaged that such a system may be deployed for monitoring synthetic ropes over lengths of 0.5 to 5 km.