Modern optical modeling and analysis programs allow users to create and analyze accurate optical and opto-mechanical systems in the software environment prior to building actual hardware based systems. The resultant accuracy of these models depends on the accuracy of the components that make up the model including the light source characteristics, surface and material properties, and the model geometry. In this paper we will consider factors that lead to improved modeling of the light source such as spectral and angular properties, the spatial distribution of light within the source, and the interaction of the light with the structure of the source. These factors are extremely important for near field modeling, especially for fiber and light pipe coupling. Several options will be discussed including simple source models such as point sources, ray files, surface properties that define optical parameters such as spectral and angular distribution, and detailed 3D solid models of the source. Simulated results for spectral, angular, and spatial distributions will be compared to actual measurements. Discussion will also include the appropriateness of each modeling approach with respect to different applications.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.