Interferometric polarization-independent modulator in LiTaO/sub 3/

Polarization-independent Mach-Zehnder modulators that utilize the off-diagonal r/sub 51/ electrooptic coefficient are produced in LiTaO/sub 3/. The waveguides are formed by Zn vapor diffusion. Extinction values of 85% at 0.633- mu m wavelength are demonstrated for both transverse electric and transverse magnetic polarization using a single control voltage and thermal tuning. The relatively large voltage-length product values (VL>or=15 V-cm) attained in these devices are attributed to a weak overlap between optical and electrical field profiles. Electrode alignment and dielectric loading are critical factors for the optimization of device operation.<
>