EFFICIENT COUPLING INTO POLYMER WAVE-GUIDES BY GRATINGS

Investigations of highly efficient grating couplers for polymer slab a nd strip waveguides fabricated by electron-beam lithography are report ed. A maximum input efficiency of 67% is achieved. The electron-beam d irect-writing technique allows one to replicate the original gratings into polymer substrates by embossing. An all-polymeric optical chip wi th efficient grating couplers is demonstrated. Waveguide grating coupl ers with blazed profile and variable grating depth are investigated. T hus, the intensity distribution of the outcoupled light is matched to a Gaussian-like profile. A focusing blazed grating that couples the li ght with an efficiency of 42% into a polymer strip waveguide is report ed. A curvature correction of the grating lines allows one to improve the focusing properties. (C) 1997 Optical Society of America.