Electro-optic modulation analysis of a Y-cut Z-propagation LiNbO3 light modulator: Comparison with an X-cut Z-propagation LiNbO3 light modulator and a dual LiNbO3 crystal type modulator

We analyzed dependence of modulation characteristics on manufacturing errors for a Y-cut Z-propagation (YZ) and an X-cut Z-propagation (XZ) LiNbO3 (LN) crystal light modulators. We investigated that the modulation of the YZ modulator is hardly affected by small rotation error of Z-axis, while the XZ modulator suffers significant influence. We also analyzed temperature characteristics of modulation of conventional temperature-compensation LN light modulator. These numerical results show that the modulated signal change of the YZ modulator due to temperature variance is not more than 2.5% of that of the temperature-compensation modulator, in the presence of applied electric field of integral times of the half-wave voltage, modulated signal of the YZ modulator is almost independent on the temperature.