%0 Journal Article %J Optics Letters %D 2015 %T Design of broadband subwavelength grating couplers with low back reflection %A Wang, Yun %A Shi, Wei %A Wang, Xu %A Lu, Zeqin %A Caverley, Michael %A Bojko, Richard %A Chrostowski, Lukas %A Jaeger, Nicolas %I OSA %K Gratings; Effective medium theory ; Subwavelength structures %P 4647--4650 %U http://ol.osa.org/abstract.cfm?URI=ol-40-20-4647 %V 40 %X We present a methodology to design broadband grating couplers using one-dimensional subwavelength gratings. Using the presented method, we design subwavelength grating couplers (SWGCs) with 1-dB bandwidths ranging from 50 to 90\&\#xA0;nm. Our designed SWGCs have competitive coupling efficiency, as high as \&\#x2212;3.8\&\#x2009;\&\#x2009;dB for the fundamental TE mode, and state-of-the-art back reflections, as low as \&\#x2212;23\&\#x2009;\&\#x2009;dB. %8 10/2015 %9 article