Automated technique to inscribe reproducible long-period gratings using a CO₂ laser splicer

We propose a technique to inscribe long period gratings (LPGs) in standard single-mode fibers (SSMFs). The proposed method uses a commercial CO₂ splicer that allows for the rotation of the fiber during laser irradiation, enabling a uniform exposure around the fiber. LPGs inscribed in SSMFs with different periods are presented. Gratings can be reproduced with a maximum difference between resonant wavelength values of less than 1 nm. Furthermore, it is possible to inscribe gratings with attenuation dips of -25  dB while at the same time obtaining polarization-dependent losses as low as 2 dB.