To accommodate the continuously growing amount of digital data handled in information and communications systems [1], optics is expected play a wider role in enhancing overall system performance by performing certain functional behavior [2] in addition to merely serving as the communication medium. The application of inherent optical features, such as parallelism, to computing systems has also been investigated [3, 4]. However, many technological difficulties remain to be overcome in adopting optical technologies in critical information and communication systems: one problem is the poor integrability of optical hardware because of spatial density restrictions imposed by the diffraction limit of light, resulting in relatively bulky hardware configurations.