Embodiments include systems and methods for integrated circuitry optical modulation. In one embodiment, an integrated circuit comprises an optical waveguide enabling multi-level modulation. The embodiment comprises an optical waveguide with integrated circuit modulators. An optical waveguide is split into at least two branches so that modulation can be imposed in each branch. In one embodiment, the branches are combined to produce an optical signal path in which additional modulation is imposed. In an embodiment of an integrated circuit optical demodulator, a received modulated optical signal is divided into branches and demodulated. Embodiments provide a single integrated circuit for multi-level modulation, thereby avoiding the disadvantages of modulation using separate discrete components. Also, a single integrated circuit for multi-level demodulation is provided.