Abstract: This paper presents the integrated circuit design, targeting a CMOS 65 nm 1.2 V technology, of a high-speed driver that provides the differential input signals to a Mach Zender Modulator (MZM), and allows tuning of the MZM operating point through adjustment of the bias voltage. A multi-voltage domain circuit is proposed, where each domain is isolated through deep n-well trenches, to face the high voltage swing and the bias regulation requirements of the MZM. The MZM device, whose prototype has been implemented in silicon photonics iSiPP50G technology, is emerging as a promising solution for radiation tolerant, in the range of 1 Grad, and high-speed, in the range of 10 Gbps, optical links. These stringent requirements are needed in high energy physics experiments in the upgrade of the Large Hadron Collider or in future Linear Colliders.