Design and fabrication of a heterodyne electrooptic modulator in lithium niobate

In this research, design and fabrication of an integrated heterodyne electrooptic modulator in lithium niobate have been presented. In this modulator, the waveguide is made by using proton exchange process; to exert two high frequency signals, deposited electrodes with Mach-Zender arms between them are used. In this method, every electrical signal is applied on one of the Mach-Zender arms, so that it can be stimulated by one specific frequency; these two signals are united optically to create frequencies equal to sum and subtraction of the input signal frequencies in the output. Also, by using finite element method, the influence of proton diffusion scale in the output light mode, electrode dimension, and configuration in the overlap integral of the light mode and electrical field, as well as electrode impedance, is estimated.