This paper presents an overview of our work on the theory, design, fabrication, and integration of micro/nano-scale optical wires and devices as applicable for all-optical generic and application-specific VLSI photonic integrated circuits. We use nano-wires, micro-resonators, plasmonic wires, photonic crystals, and metamaterials as the basic building blocks of integrated circuits and analyze the mismatch problems of various combinations of these building blocks in terms of material mismatch, size mismatch, shape mismatch, polarization mismatch, refractive index mismatch, and thermal/mechanical mismatch. We examine the efficiency of coupling and examine the possible solutions. We will then design and integrate the nano-wires and devices for various basic functions in telecommunications such as nano-couplers, wavelength splitters, power splitters, polarization splitters as applicable switches, modulators, sensors, wavelength management devices, and polarization devices. The paper discusses scientific and engineering issues of interfacing and integrating micro/nano-scale photonic devices of small and ultrasmall dimensions to a very large scale integration density. Scientific and engineering issues are examined and examples of recent progresses are presented.
