Investigation of Waveguide Mode Profiles of AWGs Using a Low-Coherence Interferometric Method

In this paper, we propose and demonstrate a novel method to characterize waveguide mode profiles in arrayed waveguide grating (AWG) devices by utilizing a low-coherence interferometric measurement. Our method calculates the waveguide mode profile from its far-field diffraction pattern obtained by the low-coherence interferometric measurement utilizing AWG as a testing vehicle. The waveguide mode profile and its far-field diffraction pattern follow the Fourier transformation relationship. Detailed formulation and analysis procedures are presented in this paper. Experimental results of waveguide mode profiles for Gaussian waveguides and multimode interference waveguides are also shown. This method is very effective in characterizing complex waveguide designs in advanced AWG devices.