Photon Design’s FDTD+FETD simulation tool OmniSim features a new design tool which allows you to design and optimise surface grating couplers automatically. You only need to specify your epitaxial structure and the properties of your output beam and OmniSim will automatically generate 2D grating profiles with routines for finding the best effiency, with a choice of periodic or apodised geometry. OmniSim can also generate the 3D layout of the grating and calculate their efficiency; for tapered gratings it will automatically generate the curvature of the grating lines based on the taper geometry. http://www.photond.com/products/omnisim/omnisim_features_04.htm