Calculation and Experimental Verification of Two-Dimensional Focusing Grating Couplers

A ray tracing method has been performed to calculate the focus spot size of two-dimensional focusing grating couplers that are produced by holographic interferometry of freely propagating wave-fronts. The calculations have been used to optimize the constructing optical configuration. Diffraction limited spot diameters of about 2 μm can be achieved for couplers at wavelength 632. 8 nm. These spot sizes have been experimentally verified for coupling and focusing TE modes which are guided in sputtered glass films on Si substrates. Copyright © 1981 by The Institute of Electrical and Electronics Engineers, Inc.