Grating Inscription Into Fluoride Fibers: A Review

Abstract

First demonstrated over four decades ago, fiber gratings, and in particular fiber Bragg gratings (FBGs), have become indispensable and ubiquitous components within fiber laser cavities as well as optical communication networks and sensor systems. Because of their overwhelming use, the bulk of published work to date has concentrated on fibers that are composed of silica-based glasses, yet those become virtually opaque at wavelengths above 2 μm, i.e., in the technically increasingly important mid-infrared part of the electromagnetic spectrum. Soft glass fluoride fibers on the other hand, in particular those composed of ZBLAN (abbreviation for ZrF 4-BaF 2-LaF 3-AlF 3-NaF), offer low-loss transmission out to wavelengths of up to almost 4 μm. However, while fiber manufacturing itself has now reached a high level of maturity, with passive fiber attenuation levels as low as 1 dB/km becoming commercially available, grating fabrication in these fibers remains challenging, and research into suitable inscription techniques is still a very active and ongoing scientific field. This review aims to provide an overview of work that has been done in this area to date with an emphasis on femtosecond-laser based fabrication methods.

Fiber Bragg grating sensors for monitoring of physical parameters: a comprehensive review

“…Femtosecond laser is the key to fabricate high quality Bragg gratings in such fibers to enable practical application of mid-infrared technology and still further research is required in its fabrication process. 130…”

Recent Advances in Fiber Bragg Grating Sensing

“…Over the years, the scientific community has relentlessly pushed the boundaries of FBG technology, leading to a cascade of breakthroughs in sensor design, fabrication techniques, and applications [ 4 , 5 , 6 ]. Our exploration will delve into the innovative strides made in the fabrication of FBGs, from traditional UV-induced gratings [ 7 ] to advanced techniques like femtosecond laser inscription [ 8 , 9 ], offering readers a glimpse into the evolution of the fabrication methodologies that underpin the success of optical fiber sensors.…”

Numerical Optimization of Dy-Doped ZBLAN Fiber Lasers for Yellow Emission

“…Compared to the widely adopted silica glass, fluoride ones offer a lower phonon energy, needed for Mid-InfraRed (MIR) emission, and better loss characteristics in the visible spectrum [10]. Although fluoride glass processing is still challenging, high-quality components, like combiners [11] and Fiber Bragg Gratings (FBGs) [12]- [15], have been demonstrated. Moreover, fibers made with ZBLAN and fluoroindate glasses, doped with different rare-earth elements, have been used for high-efficiency lasers emitting in the MIR range [14]- [21].…”