A photonic crystal (PC) cavity embedded Ba(0.7)Sr(0.3)TiO(3) (barium strontium titanate, or BST) rib waveguide, which functions as an optical filter at lambda = 1550 nm, is designed using finite-difference time-domain (FDTD) simulation. The PC cavity is composed of two 5-row photonic crystal mirrors, which are formed by air holes (radii 250 nm) arranged in triangular lattice (periodicity 625 nm) in the BST matrix. Calculations suggested that the required cavity length should be 800 nm for the resonant peak to be situated at 1550 nm. Based on this design, PC cavities were fabricated on BST thin-film rib waveguides by focused ion beam etching with satisfactory results. The transmission spectra of the BST thin-film rib waveguides with PC cavities have been measured. The results agreed well with the FDTD simulation. (C) 2010 Elsevier B.V. All rights reserved.