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Advances in OptoElectronics
Volume 2008 (2008), Article ID 752847, 6 pages
Research Article

Phase Velocity Estimation of a Microstrip Line in a Stoichiometric Periodically Domain-Inverted Modulator Using Electro-Optic Sampling Technique

Division of Advanced Electronics and Optical Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan

Received 30 April 2008; Accepted 30 July 2008

Academic Editor: Chang-qing Xu

Copyright © 2008 Shintaro Hisatake et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We estimate the phase velocity of a modulation microwave in a quasi-velocity-matched (QVM) electro-optic (EO) phase modulator (QVM-EOM) using EO sampling which is accurate and the most reliable technique for measuring voltage waveforms at an electrode. The substrate of the measured QVM-EOM is a stoichiometric periodically domain-inverted crystal. The electric field of a standing wave in a resonant microstrip line (width: 0.5 mm, height: 0.5 mm) is measured by employing a CdTe crystal as an EO sensor. The wavelength of the traveling microwave at 16.0801 GHz is determined as 3.33 mm by fitting the theoretical curve to the measured electric field distribution. The phase velocity is estimated as  m/s, though there exists about 5% systematic error due to the perturbation by the EO sensor. Relative dielectric constant of is led as the maximum likelihood value that derives the estimated phase velocity.