Sub-nanometer narrow bandwidth gratings using deeply etched SOI rib waveguides

摘要

We report the design and analysis of a novel sub nanometer narrow bandwidth grating using sidewall corrugated SOI rib waveguide. Wavelength filters with narrow bandwidth, smaller device footprint, lesser complexity and higher fabrication tolerance are essential for on-chip Wavelength Division Multiplexing (WDM) applications. In this paper, we propose a simple and effective method to obtain ultra-narrow bandwidth. The design consists of a deeply etched rib waveguide with slab sidewall corrugation for index modulation. In order to understand the device characteristics, numerical investigations were employed. With a corrugation width of 60 nm, narrow 3-dB bandwidth of 0.5 nm at 1550 nm was achieved. Our results also serve as the precursor for a Dense WDM architecture with channel spacing of 0.8 nm, realizable by varying the grating pitch.