Surface stabilized smectic liquid crystal devices can be used in a wide variety of optical filters for providing very rapid discrete, and continuous tunability. One such example, analyzed here, is the discrete switching Ferroelectric Liquid Crystal Polarization Interference Filter (FLCPIF). This filter is implemented using binary swiching surface stabilized FLC's and linear polarizers. A single-stage FLCPIF is analyzed, and the number of output spectra is determined which optimizes performance and makes the most efficient use of the devices. The extension of principles to multiple-stage FLCPIF's, and FLCPIF's which include passive retarders is discussed.