Fiber Bragg gratings in polarization maintaining specialty fiber for Raman fiber lasers

The fabrication of fiber Bragg gratings (FBG) in highly nonlinear specialty fibers for Raman fiber lasers (RFL) is described. Besides the special properties of FBGs in polarization maintaining (PM) fibers that have to be considered with regard to an optimized laser performance, a method for the post-fabrication tuning of the grating reflectivity by exploiting the nonlinear photosensitivity characteristic of the fiber is presented. Experimental results for a RFL setup with a cavity length of 3 m and FBGs directly inscribed into the active Raman fiber are discussed.