Optical　switches　are　key　components　for　routing　of　light　transmission　paths　in　data　links.　Existing　waveguide-based　Mach-Zehnder　interferometer　(MZI)　switches　occupy　a　significant　amount　of　real　estate　on-chip.　Here　we　propose　a　compact　Silicon　MZI　thermooptic　2　x　2　photonic　switch,　consisting　of　two　frustrated　total　internal　reflection　(TIR)　trench　couplers　and　TIR　mirror-based　90　degrees　waveguide　bends,　forming　a　rectangular　MZI　configuration.　The　switch　allows　for　reconfigurable　design　footprints　due　to　selected　control　of　the　optical　signal　being　transmitted　and　reflected　at　the　90　degrees　crosses　and　bends.　Our　analysis　results　show　that　the　switch　exhibits　a　chip　size　of　42　mu　m　x　42　mu　m,　the　extinction　ratio　of　similar　to　14　dB,　the　rise　and　fall　time　of　20　mu　s　and　16　mu　s,　and　the　low　switching　voltage　and　power　of　0.35　V　and　26　mW,　respectively.　This　device　configuration　can　readily　scale　its　pattern　at　the　two-dimensional　directions,　making　them　attractive　for　Silicon　photonic　integrated　circuits.　(C)2016　Optical　Society　of　America