Characterization of the growths of UV-induced birefringence in effective mode index and index modulation in fiber Bragg gratings

The ultraviolet-induced polarization-mode dispersion and polarization-dependent loss of fiber Bragg gratings in single-mode fibers (SMF-28) are characterized in a real-time and in situ fashion during grating inscription. For the first time, the growths in birefringence of both the effective mode index and the index modulation are presented.