Investigation of an electrooptic modulator formed from coupled channel diffused waveguides in LiNbO$_3$

A calculation was made of the characteristics of an electrooptic modulator utilizing coupled channel waveguides in a $Z$-cut LiNbO$_3$ crystal. Various parameters of the waveguides and electrode system were assumed in the calculation. A modulator was made from coupled channel waveguides with a control voltage of 17 V ($\lambda$ =1.06 $\mu$) and a depth of modulation $\gtrsim$ 90%. The frequency characteristic of the modulator was determined. A method was developed for the determination of the waveguide coupling coefficient by measuring the relative efficiency of second harmonic generation.