Birefringent gratings induced by polarized laser in azobenzene-doped poly(methyl methecrylate) optical fibers

Birefringence gratings induced by 532nm polarized laser in an azobenzene doped polymethyl methacrylate (PMMA) fiber and perform block were investigated. Significant photo-induced birefringence has been observed from the fiber. The maximum induced index change is about 3.1x10+MIN5) from this material. The induced birefringence was attributed to the nonlinear absorption at 532nm wavelength. It is found there is the threshold intensity of 0.29mW/cm 2 . The birefringence decayed little by little when laser turned off, a certain amount of saturation was remained. The dynamics process of the birefringence was studied. This birefringent grating may apply in the polarization dispersion compensation of the fiber communication.