FOCUSING WAVE-GUIDE GRATING COUPLER USING A DIFFRACTIVE DOUBLET

A novel focusing waveguide grating coupler comprising an integrated un iform grating coupler and binary-phase-only diffractive lens is propos ed, designed, and fabricated. Experimental results are also presented to demonstrate the device performance. This device is in direct compet ition with single-element focusing grating couplers defined by direct- write electron-beam lithography and its structure is attractive becaus e the fabrication procedure is better suited for mass production. (C) 1997 Optical Society of America.