0000000000447717
AUTHOR
Angelica Maria Mesa Yandy
Development and analysis of a model based on chirped fiber Bragg gratings employed for cracks characterization in materials
In this work a model was developed that allows to understand the behavior of a chirped fiber Bragg grating for the detection and characterization of cracks in materials. In addition to the amplitude response, we show that the group delay of the grating provides useful information for the characterization of the crack. The position of the crack can be determined thanks to the linear chirp of the grating that fixes a correlation between the spatial position and both, the wavelength and the group delay. However, our analysis shows that this simple approach has a source of error, which can be overcome if a controllable external strain can be applied to the embedded grating, additional to the st…
Spectral properties of a variable period Bragg grating including a segment isolated of external deformations
In this work the behavior of a Bragg grating of variable period (usually called a linearly chirped fiber Bragg grating — CFBG) is analyzed when a small portion of it is fixed so that its properties remain unchanged, while the rest of the grating is affected by a longitudinal deformation. The system was simulated using the Transfer Matrix Method to obtain its behavior under different levels of deformation and it was observed the appearance of negative peaks in the spectral response (transmission peaks). The analysis allowed characterizing the system with different sizes of the fixed portion (defects) (0.5 to 6 mm), for a grating with 10 cm long and 3 nm spectral width.