We present a design and simulations for a low power consumption, low manufacturing tolerance optical switch for integrated photonic lightwave circuits (PLC). The design is applicable to all material platforms, including silicon, lithium niobate, indium phosphide, glass, polymer, sol-gel, and gallium arsenide, just to name a few. The mechanism is one that functions by altering the index of refraction in the multimode slab region of a multimode interference splitter via the thermo-optic or electro-optic effect. The design is unique in that the electrodes are distributed to maintain multimode behavior, which 1. renders the device easy to manufacture via very loose tolerances, and 2. allows the multiple modes to vary adiabatically so as to maintain efficient optical power switching. The power consumption is only about four times higher than that of a Mach-Zehnder interferometer switch, and it requires much less tolerance in manufacturing.