Developments of Low Frequency Electric Field Sensor using $Ti:LiMbO_3$ Optical Modulator

$Ti:LiMbO_3$ 광변조기를 이용한 저주파 전계센서의 개발

  • 최영규 (신라대학교 광전자공학과)
  • Published : 2001.07.31


The use of an asymmetric Mach-Zehnder interferometric amplitude modulator to measure a relatively low frequency electric field strength is described. The sensitivity of an electric field sensor using a $Ti:LiMbO_3$ optical modulator is strongly affected by the shape of a electrode(probe antenna). To measure the low frequency electric field, a probe antenna of wide effective area is more useful than the usual dipole antenna. As a proof of this, the optical modulator was fabricated with a plate-type probe antenna and the usefulness of this antenna tested for measuring low frequency electric field strength. Measurements were performed in the range 0.1 V/cm to 60 V/cm at 60Hz through 100 kHz. Using a probe antenna of $10\;mm{\times}10\;mm$, the output voltage of $10^{-2}\;mV$ was measured with respect to the electric field strength of 0.1 V/cm at 60 Hz. By increasing the effective area of the probe antenna, better sensitivity is obtainable over the measured range.