Planar grating multiplexers using silicon nanowire technology: Numerical simulations and fabrications

Abstract—Planar waveguide gratings have shown great potential for the application of the wavelength division multiplexing (WDM) functionality in optical communications due to their compactness and high spectral finesse. Planar gratings based on silicon nanowire technology have high light confinements and consequently very high integration density, which is 1–2 orders of magnitude smaller than conventional silica based devices. In the present paper, we will simulate the silicon nanowire based planar grating multiplexer with total-internal-reflection facets using a boundary integral method. The polarization dependent characteristics of the device are analyzed. In addition, the planar grating multiplexer with 1 nm spacing is fabricated and characterized. Compared with measured values, the numerical results show that the sidewall roughness in the grating facets can result in a large insertion loss for the device. 1