Mach-Zehnder optical modulators and IQ modulators based on a series push-pull travelling wave electrode are provided. The modulator includes a conductive backplane providing an electrical signal path. One or more voltage control taps are electrically connected to the conductive backplane within an area underneath the travelling wave electrode and provide an equalizing DC control voltage to the conductive backplane. In other variants, a plurality of conductive backplane segments are provided, and at least one voltage control tap is electrically connected to each conductive backplane segment within an area underneath the travelling wave electrode and provides a DC control voltage to the corresponding conductive backplane segment.