Lithium niobate based Mach-Zehnder modulators are widely used in digital opticalcommunication systems, microwave photonic links and various photonics switchingsystems, but the operating bias point of the modulator is known to drift over time due toenvironment perturbations and aging effects. Therefore high precision bias controlbecomes very critical for application where either amplitude or phase information fromM-Z modulators determines the system performance. Conventional lithium niobate M-Zmodulator bias...