Affiliation:
1. Huazhong University of Science and Technology
2. Shanghai Engineering Research Center of Energy Efficient and Custom AI IC
Abstract
We present, to our knowledge, the first experimental demonstration of two on-chip gratings for perfectly vertical coupling at wavelengths of 3350 nm and 3550 nm, respectively. An anti-backreflection unit containing a fully etched trench and a subwavelength pillar is introduced in each grating period, together with a binary-approximated blazed unit, interleaving fully and shallow-etched slots in 500-nm thick silicon film. Both gratings show a strong ability to eliminate backreflection and provide predicted directionality of around 80%. The physical theoretical analysis is applied during further apodization for mitigating the computation of the optimization algorithm, improving the efficiency and optimization reliability, and increasing the fabrication robustness. The measured coupling efficiencies (CEs) of the gratings are −5.58 dB and −4.34 dB at wavelengths of 3350 nm and 3550 nm, with a 3-dB bandwidth of at least 87 nm and 210 nm, respectively.
Funder
Natural Science Foundation of Shanghai
National Natural Science Foundation of China
Subject
Atomic and Molecular Physics, and Optics
Cited by
1 articles.
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