An electro-optical modulator device includes an optical signal path partially defined by a waveguide portion, a radio frequency (RF) signal path partially defined by a conductive line portion, an interaction region where an RF signal propagating in the RF signal path interacts with an optical signal propagating in the optical signal path to modulate the optical signal, and a first tuning portion arranged proximate to the conductive line portion, the first tuning portion including a conductive portion and a switch portion operative to connect the conductive portion to ground.