Temperature sensor based on double-core optical fiber

We report the theoretical and experimental study of a temperature sensor based on the changing of the refractive index with the temperature in double core optical fibre. Because of it the coupling coefficient between two cores depends on temperature. This sensor uses the double core fibre directly as a temperature sensor as well to a data transmission. The influence of variations of the temperature from 0°C to 135°C on the coupling coefficient (refractive index) is measured and we received the relation between the temperature and the signal in coupled core. This kind of sensor can be used for public safety, health and security systems.