Micro-tapered Long Period Grating for Mid-Infrared Wavelengths

Traditionally, long period gratings (LPGs) are fabricated by exposing the optical fiber core to ultraviolet (UV) lasers to induce periodic refractive index changes [1]. Alternative techniques that bypass UV laser exposure, useful in case of non-photosensitive materials, include the use of femtosecond lasers, CO2 lasers, electric arc discharges, and resistive filament heating under tension [2,3]. The capability to fabricate intricate structures with high precision is crucial for advancing the practical applications of fluoride glass, particularly in diverse mid-infrared technologies, including sensing, filtering, and laser systems [4,5].