High efficiency silicon nitride surface grating couplers

• DOI: 10.1364/oe.16.000328
• Publication Date: 2008-01-07T17:43:28Z
• Authors: Guillaume Maire; Laurent Vivien; Guillaume Sattler; Andrzej Kazmierczak; Benito Sanchez; Kristinn B. Gylfason; Amadeu Griol; Delphine Marris-M...; Eric Cassan; Domenico Giannone; Hans Sohlström; Daniel Hill
• Keywords: Equipment Failure Analysis; Refractometry; Silicon Compounds; Transducers; 0103 physical sciences; Computer-Aided Design; Computer Simulation; Equipment Design; Models, Theoretical; 01 natural sciences; 7. Clean energy

High efficiency surface grating couplers for silicon nitride waveguides have been designed, fabricated, and characterized. Coupling efficiencies exceeding 60 % are reported at a wavelength of 1.31 mum, as well as angular and wavelength -3 dB tolerances of 4 degrees and 50 nm, respectively. When the wavelength is increased from 1310 nm to 1450 nm the coupling efficiency progressively decreases but remains above 20 % at 1450 nm. The influence of the duty ratio of the grating has also been investigated: maximum coupling efficiency was obtained at 50 % duty ratio.