Method for making an index grating in an optical fibre, and quasi-distributed sensor network realized in this fibre

摘要

A quasi-distributed sensor array in an optical fibre (10), wherein the sensors are divided along the fibre by intermodal coupling zones formed by insulating the optical fibre (10) using a laser beam (16) passing through a mask (18) having a periodic spatial transmission which matches the difference between the propagation factors of the two modes to be coupled.