An optical device includes a grounded base and an optical modulator chip having a top surface, a back surface and side surfaces. The optical modulator chip is positioned on the grounded base with the back surface facing the grounded base. The optical modulator chip includes a first ground electrode, a signal electrode and a second ground electrode located over the top surface of the optical modulator chip. The first and second ground electrodes of the optical modulator chip are interconnected on a surface of the optical modulator chip.