A fiber grating is an intrinsic sensor which changes the spectrum of an incident signal due to a change in fiber properties such as strain, temperature or polarization. The operation of a fiber grating relies on a permanent modification of this core, achieved by exposing a section of photosensitive fiber to a patterned beam of intense UV laser light. The UV light creates a periodic variation in the fiber core's refractive index—a measure of how light speed is. Optical fiber grating technology serves as a foundational stone in modern communication and sensing systems.
