Research On Practical Applications Of Optical Fiber Current Sensors

This thesis presents both the theory and the aPplication of fiber optic cuJTent sensors in detall.Electric current sensors employing highly circularly birefringent fiber are proposed. Also a novelscheme to compenwte for laser source power and ambient temperature fluctUation is proposedhere. This scheme is based on the traditiona1 signal-processing scheme with simpler and moreeffective design. Besides, the temperta effect on fiber optic current sensor is discussed. Resultsof theoretical simulation and exPerimeflts showed that the electric current sensors employinghighly circularly bireffingent fiber can comPensate for the fiuctUation effectively with straight-lineresponse tO an the sensing current.Research on detecting current employing single mode fiber is discussed in this thesis;theoretical simulation and experimellts results are presented. MoreoveT, a new concept, opticalsystem common mode rewhn ration, is brought forward, which is a concept to evaluate theantidamming caPabi1ity in a dual inPut oPtical system.Employing all fiber devices to build the all fiber optical fiber current sensor system, wedetected and monitored the large current in the Depanment of Electrical Engineering at XiamenUniversity for a long time. Compared with the tradihonal transducer, the optical fiber currentsensor has more ometallding specification on current detecting and monitoring. It shows that theoptical fiber currellt sensor can be pul into practical aPplications.A novel high gain opto-electron detecting amplifier is proposed. To resolve the problem thatweak traditional amplifiers couldn't amplify signal effectively, this type of arnplifier is designedand elaborated here.Almost all of theoretical analysis and experiments, such as how to choose the devices, how todesign the oPtical system, etc. have been exPlained clearly. Some new idea and problem met inexperiments are also forward. We believe that all we have done wilI exPedite the process of putthe fiber oPtic current sensor in to use as an industrial product.