An optical modulator device comprised of a semiconductor laser acoustically coupled to a thin film resonator is disclosed herein. The thin film resonator includes a piezoelectric crystal layer having first and second opposing surfaces, with the first opposing surface being in contact with a metallic electrode. The semiconductor laser is interposed between an acoustically reflective surface and the second surface of the thin film resonator. In a preferred implementation the acoustically reflective surface is defined by a submount underlying a substrate upon which is mounted the semiconductor laser.A frequency modulator exhibiting an improved modulation index may be achieved by integrating a superlattice structure within the active region of the semiconductor laser. The superlattice structure will preferably include a cascaded stack of stacked pairs, each stack pair constituent being of a thickness equivalent to a multiple of one-half of the wavelength of optical emission produced by the semiconductor laser of the superlattice.The optical device may also be implemented in the form of a phase modulator disposed to provide a phase-modulated optical output of predetermined frequency. Phase modulation is produced in the absence of appreciable frequency modulation by configuring the thin film resonator to be of a longitudinal length less than that of the semiconductor laser.