Description
Optical fibers made from soft glasses that have minimum loss in the infrared region are gaining remarkable attention in various applications. Among the different soft glasses, ZBLAN glass which is the most common composition of zirconium fluoride-based glasses has long been thought of as a good alternative for silica fibers in telecommunications owing to its low intrinsic loss of ~0.01 dB/km at ~2.4 µm. Further, ZBLAN-based fibers have been widely used in laser and amplifier applications owing to the high rare-earth solubility, low refractive index, and low phonon energy.
This work is devoted to unveiling the impact of preform fabrication on the core volume and core/clad interface quality, propagation loss, and measured NA of the resulting step-index fibers. Ultimately, we seek to produce high-quality ZBLAN preforms and consequently low-loss fibers, which can be used for laser applications and would be a step forward for next-generation telecommunication networks.
Due to the high cost and sophisticated techniques required for ZBLAN glass fabrication, we started by using tellurite glass, as a proxy for ZBLAN, because they share relatively similar thermal characteristics. First, we explored the optical characteristics of four step-index tellurite fibers made from cast, extruded, and cane-in-tube preforms. The results revealed that the casting method outperformed other methods due to its high-quality interface, albeit with a low-quality core volume that necessitated further optimization. Consequently, this method was selected and optimized further for the fabrication of ZBLAN preforms. The findings demonstrated that employing low-temperature core melt during preform fabrication yielded low-loss fibers, achieving a minimum loss of ~0.2 dB/m at 1.7 µm.
We will present the challenges, progress, and the future directions for the development of step-index preforms.
| I am the presenting author | Yes |
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