Thermal stability of chemical composition gratings in fluorine–germanium-doped silica fibers

Abstract

A model based on diffusion of dopants in a periodic structure has been applied to describe thermal decay of chemical composition gratings in fluorine-germanium-doped silica fibers. The good agreement between previously reported values and the diffusion coefficients derived here from experiments and models in the 1000-1200 degrees C temperature range indicate that fluorine diffusion is the main mechanism of grating decay. Experimental results also indicate that the presence of phosphorous significantly increases the decay rate of chemical composition gratings.

Thermal Evaluation of Fiber Bragg Gratings at Extreme Temperatures

“…Throughout this work many similarities to the work of Fokine were observed including the formation O-CCGs [8], similar ratios of decay rate to heat rate in formation of O-CCGs [4], and similar gratings decay behavior [4,5]. However we saw a trend of shifting to longer wavelengths at high temperatures whereas he indicated a shift to shorter wavelength [2].…”

“…The survivability of FBGs up to and above 1000°C has generated interest [4,5], but their per-formance and long term survivability at these temperatures is not well published. This paper looks at, in great detail, the performance and long term survivability of FBGs up to 1000°C through more than 700 hours of thermal cycling and over 400 hours of continuous operation.…”

Research Progress of High-Temperature-Resistant Fiber Grating and Application in the Field of Sensing

“…The process of production including the grating degeneration and regeneration, thus also known as regenerative fiber grating. This kind of grating is of so excellent high temperature stability that work normally at 1000℃ [22]. The production process of chemical composition of fiber grating includes hydrogen loading, UV, the process of hydrogen diffusion and high temperature annealing treatment, in which the grating degeneration and regeneration occurs in the high temperature annealing stage.…”

Underlying mechanisms, applications, and limitations of chemical composition gratings in silica based fibers

“…A model based on diffusion of dopants in a periodic structure has been used to study the decay behavior of CCGs and to determine diffusion constants for the grating decay [15]. The model parameters for grating decay depend on the period of the grating, temperature dependent diffusion coefficient and time.…”