Ultrasmall integrated devices based on silicon nanowires for optical communications

Planar lightwave circuits (PLCs) based on Si nanowires exhibit several serious problems due to the small cross sections of the nanowires. These problems include large scattering loss, large coupling loss to a single-mode fiber, and high dependency on polarization. Several solutions to these problems have emerged. Recent progress on Si-nanowire-based passive PLC devices encompasses arrayed waveguide grating (de)multiplexers, microring resonators, and multimode interference couplers.