The Compact Pulse Electric Field Sensing Technology Based On Integrated Optical Waveguide

Instantaneous,high-energy electromagnetic pulses will have a great impact on power operation,microwave communication and the use of instruments and equipment,Therefore,the accurate measurement of this kind of electromagnetic pulse is particularly important.The integrated optical waveguide pulsed electric field sensor is widely used in the measurement of electromagnetic pulse due to its advantages of small volume,high integration and wide bandwidth.In this thesis,a large linear dynamic range,transient pulsed electric field sensing technology is used as the research object,and an asymmetric Mach-Zehnder interferometer（MZI）type integrated optical waveguide micro-pulse based on lithium niobate（Li Nb O₃,LN）electro-optic modulation electric field sensor is proposed.This thesis mainly completes the following four aspects of work:（1）The integrated optical waveguide pulsed electric field sensing mechanism is studied.The basic working principle of LN asymmetric MZI integrated optical waveguide field sensor is analyzed,the mathematical relationship between the output optical power of the sensor system and the applied electric field is obtained.The influence of the structural parameters of the asymmetric MZI interferometer on the sensor operating point is analyzed,and the selection principle of the structural parameters of the MZI interferometer is proposed.On this basis,the hardware structure of the sensing system is designed and established.（2）The influence of the structural parameters of the conical antenna on the characteristic parameters of the sensor,such as bandwidth and sensitivity,is simulated and analyzed.Using CST STUDIO to build a simulation model,the physical relationship between the sensor’s amplitude-frequency characteristics and structural parameters such as the height and bottom width of the conical antenna is obtained.On this basis,the optimal structural parameters of the conical antenna that satisfy the conditions of broadband and transient pulsed electric field sensing are proposed.（3）An integrated optical waveguide pulsed electric field sensor with conical antenna is designed and manufactured,at the same time,a comprehensive performance test platform of the sensor is established,and the response characteristics of the sensor to microwave environment and nanosecond pulse signal are tested experimentally.The experimental results show that the output amplitude frequency response fluctuation of the sensor is less than 3d B in the frequency range of 2.6GHz～6GHz,and the measured field strength range covers 0.0135V/m～46k V/m.And it can accurately capture the time-domain waveform of nanosecond pulse signal with rise time of 0.5ns.（4）In the experimental test,we found that the response of the conventional conical antenna integrated optical waveguide pulsed electric field sensor to the standard lightning pulse signal will be distorted.To solve this problem,a single shielded electrode integrated optical waveguide electric field sensor is designed in this paper.Both theory and experiments prove that the single-shielded electrode electric field sensor proposed in this paper has a 3d B bandwidth coverage from DC to GHz,and has a flat frequency response curve in this range,which can truly restore the lightning strike pulse signal（1.2/50μs）.time domain waveform.