A novel method of achieving flat spectral response arrayed waveguide grating (AWG) in silicon-on-insulator (SOI)

Abstract

Arrayed Waveguide Gratings (AWG) have gained significant popularity in Wavelength Division Multiplexing (WDM) in recent years. One of the most important characteristics of an AWG is to have a flat spectral response in order to maximize the performance of the device and reduce crosstalk. In this paper, we present a novel method of achieving a flat spectral response AWG in silicon-on-insulator (SOI). This is achieved using free carrier doping, which ultimately introduces absorption which alter the intensity field distribution at the output of the array waveguides. By applying Fourier optics to the free space region of the AWG, this field profile is the inverse Fourier transform of the output field at the AWG, hence producing a flat spectral response. The rib of the arrayed waveguides is designed to operate in singlemode condition and exhibit minimum polarization dependence. The AWG is designed to operate at a centre wavelength of 1.55μm at a grating order of 51 with path length differences of 22.61μm. Particular emphasis is paid to the theoretical analysis and development of a flat spectral response AWG, including a number of different implantation doses.