Abstract: Provided is a method for determining a required adaption of a bias of an electro-optic modulator. The electro-optic modulator includes an input waveguide that is split into two paths. The two paths are then recombined into an output waveguide. The method includes the steps of recording a modulation voltage applied to the electro-optic modulator over a particular amount of time; recording a power at an output of the electro-optic modulator in response to the modulation voltage over the particular amount of time; correlating the recorded modulation voltage and the recorded power; and determining the required adaption of the bias based on the correlation between the recorded modulation voltage and the recorded power.