摘要
光纤电压互感器中电光晶体 BGO( Bi4 Ge3 O12 )的缺陷、杂质及内部残余应力引起自然双折射 ,降低仪器的电压测量精度。从理论上分析了晶体在不同方向承受应力时不同通光方向上的双折射 ;又从热光效应的原理出发 ,推导出调制度的变化与温度、电压之间的定量关系 ,得出调制深度对温度的变化率与调制度本身成正比、与外施电压成正比的结论。因此 ,为提高仪器的温度稳定性 ,保证必要的灵敏度 ,必须使施加到电光晶体上的电压合理。 BGO晶体的吸收和色散较小 ,对光纤电压互感器测量精度的影响不大。
The faults,impurity and residual stress within the electro optic crystal BGO(Bi 4Ge 3O 12 ) of optic fiber voltage transformer will cause a natural birefringence and reduce the voltage measuring accuracy of instrument.The birefringence in the different clear directions when the crystal suffered the stress from the different directions is analyzed in theory.A quantitative relation among modulation level,temperature and voltage is derived from the thermo optic effect,i.e.,the rate of change of modulation depth with temperature is in direct proportional to modulation depth itself and applied voltage.In order to improve the temperature stability of the instrument and maintain a necessary sensitivity,the voltage applied to the electro optic crystal must be reasonable.The absorption and dispersion of the crystal is small and their influence on the measuring accuracy of optic fiber voltage transformer is not large.
出处
《光电工程》
CAS
CSCD
2000年第4期67-71,共5页
Opto-Electronic Engineering
基金
湖北省自然科学基金资助项目!( 98J0 67)
关键词
光纤电压互感器
电光晶体
测量精度
Optical fiber voltage transformer
Electro optical crystals
Measuring accuracy
Voltage measurement
Electro optical effect
