High-efficiency mid-infrared on-chip silicon grating couplers for perfectly vertical coupling.
Opt Lett
; 48(2): 239-242, 2023 Jan 15.
Article
en En
| MEDLINE
| ID: mdl-36638427
ABSTRACT
We present, to our knowledge, the first experimental demonstration of two on-chip gratings for perfectly vertical coupling at wavelengths of 3350â
nm and 3550â
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 -5.58â
dB and -4.34â
dB at wavelengths of 3350â
nm and 3550â
nm, with a 3-dB bandwidth of at least 87â
nm and 210â
nm, respectively.
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01-internacional
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MEDLINE
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En
Revista:
Opt Lett
Año:
2023
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Article