We have developed a conservative logic, reversible optoelectronic intensity modulator. The device, called an X-modulator, works by using quantum wells in a nearly symmetric Fabry-Perot cavity to direct an incident optical beam to transmit through the device or to be reflected from the device depending upon the state of the switching element. The first experimental device simultaneously switches reflectivity and transmission from 6% to 60% and 60% to 6% respectively. We also examine the cavity design parameter space and the effects of incident angle on device performance. Furthermore, experimental results from combinations of stacked devices are discussed. Explanation of a voltage reduction method by grading material composition will also be provided. After discussing the individual device performance, a discussion of simple systems utilizing X-modulators will be given. In particular an analysis of crossbar switches, field programmable gate arrays, and lookup tables will be given as well as a description of wavelength demultiplexing applications.