A device may include a substrate. The device may include an optical waveguide formed in or on the substrate. The device may include a signal electrode extending along a longitudinal axis. The signal electrode may include a first portion with a proximal end that is proximal to the optical waveguide, to induce a signal from the signal electrode to the optical waveguide. The signal electrode may include a second portion, at least partially attached to or continuous with a distal end of the first portion. The device may include one or more ground electrodes that form an enclosure. The enclosure may enclose the signal electrode with regard to a side of the substrate in a plane perpendicular to the longitudinal axis.