A Demultiplexer with Blazed Waveguide Sidewall Grating

We propose a new type of waveguide diffraction grating demultiplexer with a very small footprint, designed for the silicon-on-insulator platform. Summary Integrated waveguide de-multiplexers as AWG's and etched echelle gratings (EEG) have been designed in the last decade to accommodate the specifications of telecommunication for narrow channel spacing. Now, with new applications with relaxed specifications (such as FTTH, optical sensing, etc.), new designs have emerged for compact coarse WDM devices. Among them we have been interested in the performance of the dispersive waveguide grating recently published by Hao et al [1], and we propose the use a sub-wavelength antireflection structure to improve its design. The device is presented in Fig. 1; it consists essentially of a curved waveguide on the left of the picture, in which the external wall is etched as a first order grating in order to diffract the light, originally in the waveguide, towards the output waveguides at the right. The arrangement is based on a Rowland circle (RC) configuration, with the radius o