An optofluidic nano-Bragg microcavity filter is designed using three-dimensional finite difference time domain technique and fabricated using electron-beam lithography and reactive ion etching techniques on a silicon-on-insulator (SOI) material. Continuous filter tuning is possible via small refractive index changes by introducing different fluids. An index change of 0.03 corresponds to a peak resonance wavelength shift of approximately 1 nm. The SOI chip is also integrated with a polydimethlysiloxane microfluidic chip for the fluid delivery. (C) 2010 American Vacuum Society. [DOI: 10.1116/1.3498763]