Fiber-chip grating coupler based on interleaved trenches with directionality exceeding 95%

DOI	Resolve DOI: https://doi.org/10.1364/OL.39.005351
Author	Search for: Alonso-Ramos, C.; Search for: Cheben, P.¹ORCID identifier: https://orcid.org/0000-0003-4232-9130; Search for: Ortega-Moñux, A.; Search for: Schmid, J. H.¹; Search for: Xu, D. -X.¹; Search for: Molina-Fernández, I.
Affiliation	National Research Council of Canada. NRC Institute for Microstructural Sciences
Format	Text, Article
Subject	grating couplers
Abstract	We propose a fiber-chip grating coupler that interleaves the standard full and shallow etch trenches in a 220 nm thick silicon layer to provide a directionality upward exceeding 95%. By adjusting the separation between the two sets of trenches, constructive interference is achieved in the upward direction independent of the bottom oxide thickness and without any bottom reflectors, overlays, or customized etch depths. We implement a transverse subwavelength structure in the first two grating periods to minimize back-reflections. The grating coupler has a calculated coupling efficiency of CE ~ -1.05 dB with a 1 dB bandwidth of 30 nm and minimum feature size of 100 nm, compatible with deep-UV lithography.
Publication date	2014-09-09
Publisher	OSA Publishing
In	Optics Letters 39, no. 18: 5351–5354.
Language	English
Peer reviewed	Yes
NPARC number	21272925
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Record identifier	777f5949-2649-48bd-ac4d-c122e7010da9
Record created	2014-12-03
Record modified	2020-04-22