Fiber Optic Current Sensors

Abstract

Fiber optic current sensors utilize the Faraday effect which causes the polarization of the light to rotate. These sensors have several advantages compared to conventional current measurement methods such as electrical insulation and small size and weight. There is however requirement on specially manufactured fiber and components in order to cancel out undesired linear birefringence which will transform the polarization. In this thesis the foundations of these system have been investigated and tested in a configuration including a SMF (Single Mode Fiber) as the sensing coil terminated with a Faraday mirror. The wavelength of operation is around 1550 nm and the number of loops in the sensing coil is approximately 2100. The SMF was not preferable in these types of sensors and it is recommended to use spun highly birefringent fiber for such large number of loops in order to cancel out the linear birefringence properly.