are successfully fabricated using a nanoimprint technique a first method employs the use of direct imprinting to fabricate pmma and ps micro ring devices of less than 1 5 u03bcm in height this first method may also be used to fabricate taller micro ring structures through the use of mechanically stronger polymers such as polycarbonate alternatively a second method of fabrication is provided that employs a template filling method to fabricate larger micro ring devices than could otherwise be fabricated using the aforementioned direct imprinting technique this second method of fabrication may also be used in connection with those polymers that are traditionally difficult to directly imprint the fabricated devices can operate with air cladding or with other fluid media as cladding depending on the application for bio and chemical sensor application having a fluid cladding is essential for the chemicals and biomolecules to interact with the micro ring waveguide additionally according to the principles of the present invention a thermal flow process to reduce surface roughness of polymer waveguides is provided this process further provides an effective way to modify the submicron gap separation that controls the coupling of the optical field to the micro ring waveguide the polymer micro ring devices made from polystyrene ps were fabricated by using a nanoimprinting technique after the polymer waveguide had been formed the samples are heated to a temperature close to the glass transition temperature of ps for a predetermined amount of time this heat treatment reduces the viscosity of ps and enhances its fluidity sem characterization clearly shows that the sidewall roughness can be greatly reduced which is a result of surface tension effect of the polymer higher.