Reduction of intrinsic polarization dependence in arc-induced long-period fiber gratings

We report a production technique of reducing the polarization-dependent loss (PDL) always present in arc-induced long-period fiber gratings (LPFGs). The proposed fabrication method is based upon the rotation of the optical fiber by an axial angle of 180 deg at each electric arc discharge, therefore, inducing opposite point-by-point asymmetric modulations over the entire length of the LPFG. PDL measurements of different arc-induced LPFGs fabricated by both the conventional and proposed method are presented. Finally, the obtained results show a significant decrease of the intrinsic PDL of arc-induced LPFGs with the proposed fabrication technique. (C) 2018 Society of Photo-Optical Instrumentation Engineers (SPIE)