Methods for Low Crosstalk and Wavelength Tunability in Arrayed-Waveguide Grating for On-Silicon Optical Network

Abstract : Arrayed waveguide gratings (AWGs) are used to accomplish complex functionalities in dense wavelength division multiplexing networks, as well as in signal processing, measurement, characterization or sensing. In this work, we discuss the design and the experimental characterization of a 6 x 400 GHz channel-spaced AWG to be used as wavelength multiplexer/demultiplexer in a silicon-on-insulator based optical transport network. We adopted a whiskered-shaped star coupler design to investigate how the reduction in the reflectivity of the free propagation region boundaries affects the overall performances of the AWG. We demonstrated 2.9 dB insertionloss, which does not include fiber coupling loss, and (-24.4 +/- 0.1) dB crosstalk for a design realized with a single etching technique. Moreover, we demonstrated an efficient fine-tuning (7.5 nm/W) of the spectral position of the AWG output channels.