The focus of this dissertation is the integration of 2D materials on a silicon photonics platform for optoelectronic applications. The current state of waveguide integrated photodetectors and modulators is reviewed and provides a context for the work detailed in the following chapters. The first dual-function graphene photodetector and modulator is demonstrated in a simple geometry that allows simultaneous use of both functionalities. Next, the first waveguide integrated black phosphorus photodetector is demonstrated with superior dark current to its graphene counterparts. Operation speeds six orders of magnitude higher than any previous black phosphorus detector is demonstrated together with a clear understanding of the photocurrent mechanisms that dominate the device. Finally, the nonlinear response of black phosphorus was used to investigate the intrinsic speed of a photodetector. Subsequent observation of third-harmonic generation led to characterization of chi(3) in black phosphorus for the first time.