Study On Working Point Stabilization Method Of Lithium Niobate Electric Field Sensor

The integrated optical waveguide lithium niobate electric field sensor has the characteristics of small size,strong electromagnetic interference resistance,small disturbance to spatial electric field,and large bandwidth,which is very suitable for application in electric field sensing.Due to the fact that lithium niobate electric field sensors are susceptible to external conditions(especially temperature),research has been carried out on the methods for stabilizing the operating points of electric field sensors.The main research contents include:1.A method for stabilizing the working point of electric field sensors based on wavelength tuning is implemented.Using an asymmetric electric field sensor,the working point of the electric field sensor can be changed by tuning the wavelength to compensate for the impact of external factors on the working point of the sensor.Tune the laser using a control module and receive feedback optical signals from the sensor output.Find the optimal working wavelength of the electric field sensor by the maximum and minimum values in the feedback signal.Compare and analyze the working point obtained by the method experiment with the cosine curve fitting results.2.Design and implement the method of working point stabilization of electric field sensor based on cosine curve fitting.The disadvantage of wavelength tuning based work point stabilization method is analyzed,that is,only the maximum and minimum values in the work point curve that are most likely to be misjudged are used in the selection of work points.In the more complex electric field sensing system,the operating point error obtained by this method is relatively large.Aiming at this disadvantage,a method of working point stabilization based on cosine curve fitting is designed and implemented.By selecting an appropriate wavelength range and averaging all feedback signals,the feedback voltage corresponding to the optimal operating point can be obtained,thereby finding the optimal operating wavelength of the electric field sensor.In this method,a self checking function of the electric field sensing system is added,which can automatically detect whether each module in the electric field sensing system is working properly.An electric field sensing box has been fabricated,including a microcontroller control board designed and manufactured independently.A nanosecond strong electric field pulse measurement experiment was conducted using the electric field sensing system in the chassis,verifying the working point stability method based on cosine curve fitting.3.Design and implement the real-time stability method of the working point of the electric field sensor.Due to changes in external conditions,the electric field sensing system also needs to suspend electric field measurement and resume work point stabilization.Aiming at this problem,a new method for stabilizing the operating point is designed and implemented,which can make the electric field sensing system work continuously for a long time.When the electric field to be measured is a high-frequency electric field,the real-time change of the DC feedback signal can reflect the drift of the working point of the electric field sensor.Conduct temperature experiments on electric field sensors.After the temperature changes,this method only needs about 0.5 seconds to complete the stability of the working point,and the time consumption is far lower than wavelength scanning.