This dissertation presents each component of and a path towards heterogeneously integrated GaAs type III-V lasers bonded to Si3N4 passive waveguides on silicon, targeting visible integrated photonics on silicon. A continuous-wave Fabry-P\'erot laser, tapered mode converters from III-V to Si3N4, and Si3N4 sidewall distributed Bragg reflector elements, all made with an integrable process flow, are demonstrated to prove this principle. The goal of this integration is to combine electrically pumped InGaAs multiple quantum well (MQW) active material with low-loss, spectrally wide-bandwidth waveguides to enable compact, novel photonic integrated circuits. An additional benefit with Si3N4 is its lower thermal drift relative to silicon. Additionally, demonstrations of TiO2 based guides with ~pm/K thermal drift are presented to explore the possibilities of athermalized waveguides on silicon. Both TiO2 core and clad waveguides are studied, and new materials information on amorphous sputtered TiO2 are reported. As integration with such waveguides could open opportunities for novel athermal lasers, some passively athermal designs and designs with integrated athermal wavelength references are presented which show the merit of an integrated approach.As much process development was required to bring all of the device demonstrations presented in this dissertation to fruition, key process developments are highlighted and explained in detail to assist in any similar future developments.Finally, the vision of heterogeneous integration as an enabler for ultra-broadband photonic integrated circuits beyond existing InP/Si photonic integrated circuits is presented as future work
