A novel type of interferometer was designed and tested experimentally. It combines the advantages of the spatial path separation used in the two-wave polarized Jamin interferometer and the high sensitivity that characterizes the multiwave Fabry-Perot interferometer. Furthermore, when it is sandwiched between crossed polarizers it shows a sensitivity to intracavity anisotropies that is proportional to the square of the Fabry-Perot interferometer's finesse.