REVERSIBILITY OF PHOTOINDUCED BIREFRINGENCE IN ULTRALOW-BIREFRINGENCEFIBERS

New measurements of the birefringence induced in ultralow-birefringenc e fibers by a succession of orthogonally polarized UV side exposures s how the reversibility of the process. Moreover, it is shown that the b irefringence growth depends on two parameters, the total irradiation d ose and the nature of the successive polarized UV side exposures. Thes e observations indicate that geometric asymmetry is not the major caus e of the birefringence and confirm a model of birefringence growth bas ed on dipole alignment. (C) 1996 Optical Society of America