We review a polymeric waveguide technology developed to produce affordable high-performance optical components that address the needs of both the telecom and the datacom industries. We engineer advanced organic polymers that can be readily made into planar singlemode, multimode, and micro-optical waveguide structures of controlled numerical apertures and geometries. These materials are formed from highly crosslinked acrylate monomers with specific linkages that determine properties such as flexibility, toughness, optical loss, and environmental stability. These monomers are intermiscible, providing for precise continuous adjustment of the refractive index over a wide range. In polymer form, they exhibit state-of-the-art loss values, suppressed polarization effects, and exceptional stability, enabling their use in a variety of demanding applications. Waveguides are formed photolithographically, with the liquid monomer mixture polymerizing upon illumination in the UV via either mask exposure or laser direct writing. A wide range of rigid and flexible substrates can be used. The devices we describe include a variety of passive and thermo-optically active elements that achieve a variety of coupling, routing, and filtering functionalities. These devices can be either individually pigtailed and packaged components or they can be part of a massively parallel photonic integrated circuit on the multichip module (MCM), board, or backplane level.