Optimizing the broadband performance of TPF's high-contrast imaging testbed through modeling and simulations

We have carried out some investigation to optimize the broadband performance of the high-contrast imaging testbed (HCIT) at JPL through optical modeling and simulations. The analytical tool is an optical simulation algorithm developed by combining the HCIT's optical model with a speckle-nulling algorithm that operates directly on coronagraphic images, an algorithm very similar to the one that has been used on the HCIT. We have experimented in our simulations with different designs for the occulting mask and the Lyot Stop, and also tried several different speckle-nulling approaches. Some results predicted by our simulations agree well with the results measured on the HCIT. In this paper we describe the details of our simulations and present our results.