Research on the FBG's High Temperature Sustainability Influenced bythe Doping Process

摘要

The numerous potential applications of UV-induced fiber Bragg gratings (FBGs) in fiber optic sensing and telecommunication have generated a significant interest in this field in recent years. However, two major factors—the photosensitivity of the fiber in which the grating is written and the thermal stability of the grating—are of prime importance in terms of choosing the most appropriate fiber to use and of the long-term functionality of the grating over a wide range of temperatures. Based on the plasma chemical vapor deposition (PCVD) process, the high Ge (Germanium) and Ge/B (Germanium/Boron) co-doped photosensitive fiber were developed. It is mature technique that to precise control the dopant quantity by PCVD process. The photosensitive fibers with different doping composition and doping concentration have been studied. Based on the experimental results obtained from studies of several kinds of photosensitive fiber on both the photosensitivity and the temperature sustainability of the FBGs written into them, the experimental results exhibit that the Boron dopant brings deleterious influence on the FBG's high-temperaturesustainability. The FBG sustainable temperature will become lower than 500°C when the Boron concentration reaches14% in germanium highly doped photosensitive fiber.