Design of Phase Detection of All-Fiber Voltage Sensor

An all-fiber voltage sensor based on inter-mode interference is introduced.The coherent mode-spot light intensity which comes from dual-mode fiber is detected by two diodes.The inter-mode phase difference change caused by the measured voltage is measured from the change of mode-spot light intensity.The principle of phase tracking of the system with source-contained homodyne detection method is discussed. The phase detection system and circuit is presented.The simulation and experiment results show that this design scheme can achieve the purpose of phase tracking.