A Mach-Zehnder modulator (MZM) includes a first optical path with a first diode coupled to a first voltage signal node and configured to modify a phase of a first light signal transmitted through the first optical path. A further diode is positioned in the first optical path and configured to introduce a phase shift to the first light signal. A second optical path includes a second diode coupled to a second voltage signal node and configured to modify a phase of a second light signal transmitted through the second optical path. A first voltage signal carried on the first voltage signal node and a second voltage signal carried on the second voltage signal node each vary between a reverse biasing voltage level and a forward biasing voltage level. An optical coupler is coupled to the first and second optical paths.