Phase Velocity Estimation of a Microstrip Line ina Stoichiometric Periodically Domain-InvertedLiTaO3Modulator Using Electro-Optic Sampling Technique

[摘要] We estimate the phase velocity of a modulation microwave in aquasi-velocity-matched (QVM) electro-optic (EO) phase modulator(QVM-EOM) using EO sampling which is accurate and the most reliabletechnique for measuring voltage waveforms at an electrode. Thesubstrate of the measured QVM-EOM is a stoichiometric periodicallydomain-invertedLiTaO3crystal. The electric field of a standing wavein a resonant microstrip line (width: 0.5 mm, height: 0.5 mm) is measured byemploying a CdTe crystal as an EO sensor. The wavelength of the travelingmicrowave at 16.0801 GHz is determined as 3.33 mm by fitting the theoreticalcurve to the measured electric field distribution. The phase velocity isestimated asvm=5.35×107 m/s,though there existsabout 5% systematic error due to the perturbation by the EO sensor.Relative dielectric constant ofεr=41.5is led as the maximumlikelihood value that derives the estimated phase velocity.

[学科分类] 电子、光学、磁材料