Infrared interferometric nulling is a promising technology for exoplanet detection. Nulling research for the Terrestrial Planet Finder Interferometer has been exploring a variety of interferometer architectures at the Jet Propulsion Laboratory (JPL). Three architectures have been identified as having promise for achieving deeper broadband IR null depths. Previous nulling research concentrated on layouts using dispersive elements to achieve a quasi-achromatic phaseshift across the passband. However, use of a single glass for the dispersive phase shift method inherently limits the nulling bandwidth. JPL is researching use of multiple glass types to increase null depth and bandwidth. In order to pursue nulls over much broader wavelength regions, nondispersive interferometer architectures can be employed. Toward this end, JPL has been researching two reflective architectures as nulling interferometers. The key enabling technology for this and other nondispersive field flip architectures is single mode spatial filtering devices. We have obtained results with both pinhole spatial filtering and single mode fibers.© (2005) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.