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

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 dir...

Full description

Saved in:
Bibliographic Details
Published in:Optics letters 2014-09, Vol.39 (18), p.5351-5354
Main Authors: Alonso-Ramos, C, Cheben, P, Ortega-Moñux, A, Schmid, J H, Xu, D-X, Molina-Fernández, I
Format: Article
Language:English
Subjects:
Computational efficiency
Computing time
Diffraction gratings
Etching
Gratings (spectra)
Joining
Lithography
Noise levels
Trenches
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary: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.
ISSN:0146-9592
1539-4794
DOI:10.1364/OL.39.005351