Abstract
In this paper we present preliminary experimental results of an improved dual grating-assisted directional coupler. As the top SiON layer is thicker, the total insertion loss is reduced, and coupling efficiency significantly increased in the Lband wavelength region, compared to the previously reported results. The coupling efficiency is in the 42-56% range for both C-and L-band wavelength regions. Temperature dependence of the coupler has been also investigated. © 2006 IEEE.