Long period gratings in unconventional optical fibers made with 3D-printed periodic interdigitated grooved structure

This work outlines the analysis and implementation of mechanically induced long-period gratings (MILPGs) in both conventional and non-traditional optical fibers, encompassing standard single-mode fiber (SMF-28), double-cladding fibers such as Thorlabs DCF-13 and Nufern S-1310, and a P-doped fiber. The fabrication of grating involves the application of transverse pressure to specially grooved plates, inducing periodic alterations in fiber structure and refractive index (RI). An innovative aspect in the proposed fabrication process is the use of stereolithography (SLA) 3D printing technique to create interdigitated, nearly sinusoidal-shaped grooved structure. Through this approach, we evaluated the performance of the MILPGs in order to comprehend how weight, grating length and fiber coating influence the effectiveness of MILPG. The characterizations were performed within wavelength range of 1100-1700 nm. The resulting devices showcase superior spectral characteristics, including negligible power losses and well-defined narrow attenuation bands. Notably, the proposed fabrication method stands out for its cost-effectiveness, it is easy-to-use and capable of rapid production. As a wide range of optical fibers have been explored in this work, each of which possesses unique geometrical and optical characteristics and this comprehensive exploration of fabrication parameters opens avenues for applying these devices in sensing and communication, marking the first comprehensive investigation of MILPGs in these specific optical fibers, thereby making a distinctive and innovative contribution to the field.