Novo método de fabricação de redes de período longo com baixa perda dependente da polarização

Abstract

This work presents the fabrication of arc-induced long period fiber gratings with reduced polarization-dependent loss. An important characteristic of arc-induced gratings is their intrinsic high polarization-dependent loss, which limits their use in sensing and optical communications applications. The proposed technique is based on the axial rotation of the optical fiber after each electric arc discharge. The induced transverse asymmetric perturbation rotates along fiber axis. Therefore, it is possible to average the contribution of transverse inhomogeneity of the refractive index induced along the fiber grating length and reduce the undesirable effects of polarizationdependent loss. The fabrication technique was described, the polarization-dependent loss behavior of the produced gratings was investigated. The experimental results show that it is possible to substantially reduce the intrinsic polarization-dependent loss of these gratings. Finally, we investigated the torsion-dependent spectral response of a long period grating. The results show that it is possible to achieve an enhanced linear torsion sensitivity of 0.197 nm/(rad/m), which is higher than that of conventional arcinduced long period gratings.