The last decade has witnessed an incredible increase of Internet traffic that has spurred a rapid evolution of optical communication technology for higher data transmission capacity. Digital signal processing (DSP) has enabled coherent optical communications with advanced modulation formats, which led to giant leaps of single-channel data rates in long-haul transport networks. Next-generation fiber-optic communication systems will have a dramatically increased complexity that cannot be achieved using discrete optical components. Photonic integrated circuits are the most promising solution to the dilemma of scaling system complexity while reducing cost per bit/s. Further advances for future ultra-high-capacity optical transmission systems require synchronized development of integrated photonic devices and DSP algorithms will enable dramatically improved performance and higher power efficiency for ultra-high capacity optical transmission systems. It this project, we examine high-quality coherent signal generation applying advanced DSP algorithms to significantly improve the state of the art of integrated coherent optical transmitters.