Patent ID: 6041069
Filing Date: 2000-03-21
Classification: G02B,H01S

Abstract:
A rare earth doped fibre laser including first and second fibres,the first optical fibre including a laser-active rare-earth dopant, andthe second optical fibre being photosensitive to enable a refractive index grating to be recorded therein and being optically coupled to the first fiber, said second optical fibre including a reflector comprising a refractive index grating formed in its core, the grating having been formed by exposing the second fibre to a first spatially periodic pattern of optical radiation such that said first pattern becomes recorded in the core of the second fibre, the spatial periodic pattern having been configured such that the laser operates with a selected predetermined wavelength with an extremely narrow bandwidth, determined by the spatially periodic pattern, and is selectively tunable for extremely narrow bandwidth operation at a different wavelength by exposing the second fibre to a second spatially periodic pattern of optical radiation such that said second pattern becomes recorded in the core.