Dependence of dispersive and birefringence properties of silicon nanowires on waveguide dimensions.

We study numerically the dependence of dispersive and birefringence properties of silicon nanowires on waveguide dimensions and show that they have a strong geometrical dependence when nanowire dimensions become comparable to the wavelength of light inside the device. We develop a graphical method for engineering two or more dispersion parameters simultaneously and use it to demonstrate the possibility of fabricating silicon nanowires with flattened dispersion curves over a wide spectral range with normal or anomalous nominal values. We quantify polarization-mode dispersion through the differential group delay and show that it can acquire large values for properly designed nanowires. Our analysis should help in designing silicon-based photonic integrated circuits.