Authors:	Dylewicz, R, Hogg, R.A., Airey, R., Paszkiewicz, R, P. Bienstman, Patela, S.
Title:	Simulations of nanograting-assisted light coupling in GaN planar waveguide
Format:	International Journal
Publication date:	7/2011
Journal/Conference/Book:	Optical and Quantum Electronics
Volume(Issue):	42
DOI:	10.1007/s11082-011-9485-4
Citations:	5 (Dimensions.ai - last update: 17/11/2024) 5 (OpenCitations - last update: 3/5/2024) Look up on Google Scholar
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Abstract

The numerical simulations of nanogratings integrated with gallium nitride (GaN)
planar waveguides as well as the experimental in-coupling results are presented. A simulation
tool based on the eigenmode expansion method and advanced boundary conditions provided
a rigorous model of 400-nm-period grating couplers. A full-vectorial Maxwell solver allowed
performing a number of simulations with varying grating parameters, where coupling efficiency,
reflection and transmission characteristics of device were calculated. Gratings with
different etch depths and arbitrary shapes were simulated using a staircase approximation,
with an optimized number of steps per single slope. For the first time, an impact of dry
etch processing on GaN coupler efficiency was evaluated, due to the inclusion of the sloped
sidewalls, with regard to the technological constrains. Finally, the experimental results in the
visible spectrum region ()" = 633 nm), for 400-nm-deep gratings etched in GaN waveguide,