A 2x2 polymeric thermo-optic switch is designed and fabricated. It is made of four asymmetric Y-branch waveguides connected in cascades. Polymers used for the lower cladding layer and core layer are fluorinated polyimides with different refractive indices. Polymer used for the upper cladding layer is teflon. The channel waveguides forming the device have been fabricated by the reactive ion etching method. The measured crosstalk for each path is less than -20 dB for TE polarization. The power consumption is about 650 mW. The fabricated device remains in the cross state without power consumption.