Mechanical properties of fibre Bragg gratings

Because of these advantages, FBGs have been applied as embedded sensors to monitor or measure the internal strain of composite structures. Friebele 

With FBG sensors being prepared for field applications, growing interest is focused on the mechanical reliability of the fibre gratings. The influence of various parameters like humidity, - chemical composition of coating,  

A fibre Bragg grating consists of a modulation in the refractive index, n(z), along a short length (z) of the core in germania-doped silica fibre with a period of A, which is given by  

The inscription of permanent Bragg grating can be achieved in the core of an optical fibre by interference of two coherent ultra-violet light beams. The grating thus has a holographically induced refractive index modulation with a period A = sin(0/2), where 6 is the angle between the two writing beams 

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