The fiber optic measurement technology for parameters apart from the main applications of strain and temperature is based exclusively on the technology of the fiber bragg grating (FBG). FBGs are created by exposing the fiber to a periodic pattern of intense UV radiation at a specific position of the fiber. Several FBGs (typically 15 to 20) can be written in a single fiber and read out simultaneously with one system. This technology enables measurements along a glass fiber over long distances up to several kilometers with a spatial resolution of about 1 cm. Depending on the size to be measured, specially developed sensors are used. The readout device, the interrogator, on the other hand, is the same as that used for other measured variables (temperature and strain).