Experiments using a Mach-Zender type interferometer have been carried out to study the polarization modulation in a single mode optical fiber induced by cylindrical PZT phase modulators. The polarization modulation has been observed to increase drastically as the modulation frequency is increased. The frequency dependence of the polarization modulation has been calculated by a two dimensional acoustic model and results of the calculation have been campared with experimental data. It has been demonstrated that the polarization modulation can be reduced by inserting a half wave plate in the middle of the coiled fiber around the cylindrical PZT phase modulators.
