Significance Statement
The present work investigates the waveguide dispersion of subwavelength structures, and proposes that the waveguide dispersion can be reduced by reducing the period of subwavelength structures. A 3 dB bandwidth increment of 20% has been observed by introducing this concept into previously demonstrated grating couplers. To fully exploit the bandwidth merits of the structures, gratings with interleaved subwavelength structures were designed and fabricated. Two typical types of interleaving geometries have been investigated. Both demonstrated a 1 dB bandwidth ~70 nm, a 3 dB bandwidth ~117 nm, and a peak efficiency ~−5.1 dB at 1570 nm for transverse-electric polarized light. The simulation confirms that the dispersion engineering adds an extra 12 nm to the 1 dB bandwidth.
Optics InfoBase , Conference Papers , CLEO_SI , 2013 , CTh4F , Page CTh4F.7
Xiaochuan Xu, Harish Subbaraman, David Kwong, John L. Covey, Amir Hosseini, andRay T. Chen
University of Texas at Austin, United States and
Omega Optics, Inc., United States.
Abstract
A wideband grating coupler based on interleaving dispersion engineered subwavelength structures has been proposed and experimentally demonstrated. The fabricated device shows a coupling efficiency of 5.1dB and a 1dB bandwidth of 70 nm.
© 2013 OSA
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