Asymmetric Fabry-Perot modulators containing an electrooptic polymeric film are described. The designs of these structures are optimized for reflection operation by maximizing both cavity finesse and the effective field strength acting across the spacer region, hence minimizing drive voltages. The electrooptic responses of these devices are modeled and the voltages required to realise 3-dB and 10-dB modulation are calculated. It is thus demonstrated that organic thin-film-based Fabry-Perot devices are potential candidates for high-speed, low-drive-voltage, electrooptic switches, modulators, and interconnect elements. Experimental results from prototype devices are also presented.