Point-by-point inscription of phase-shifted fiber Bragg gratings by femtosecond IR radiation in passive and active rare-earth doped optical fibers

The paper presents the results on inscription of FBG with phase shifts in passive and active rare-earth doped optical fibers by the new versatile method based on femtosecond laser direct point-by-point writing. The technique allows to create phase-shifted FBGs with different values and position of phase shift along the fiber.