Induction Brazing of Type-I Fiber Bragg Gratings Into Kovar Ferrules Exploiting Curie Transition

While soldering fiber Bragg gratings into ferrules may allow them to overcome their inherent mechanical and chemical weaknesses, the high temperatures required to achieve reliable encapsulation can result in decreased grating reflectivity. In this paper, finite element models and data from on-line temperature measurements of regenerated gratings during induction heating are analyzed. The results are used to design and implement an optimized methodology, which allows standard, type-I gratings to be brazed into ferrules with high-temperature solders, while ensuring low reflectivity losses.