Share Email Print
cover

Proceedings Paper

High-directionality L-shaped fiber-chip grating couplers realized in 300-mm silicon-on-insulator platform with deep-ultraviolet lithography (Conference Presentation)
Author(s): Carlos A. Alonso-Ramos; Daniel Benedikovich; Diego Pérez-Galacho; Sylvain Guerber; Vladyslav Vakarin; Guillaume Marcaud; Xavier Le Roux; Eric Cassan; Delphine Marris-Morini; Pavel Cheben; Frédéric Boeuf; Charles Baudot; Laurent Vivien

Paper Abstract

Fiber-chip grating couplers providing high-efficiency, robustness and cost-effectivity are recognized as a key building block for large-volume photonic applications. However, the efficiency of silicon-on-insulator (SOI) grating couplers is limited by the mismatch between the beam diffracted by the grating and the fiber mode, back-reflections at the grating-to-waveguide interface, and the power radiated towards the substrate. While the first two limitations can be overcome by grating apodization, the limited diffraction efficiency (directionality) towards the fiber remains a challenge. Typically, grating directionality is optimized by backside metallization, distributed Bragg mirrors, multi-level grating architectures or non-standard etching depths. However, these approaches yield comparatively complex structures, which in turn, come with the expense of extra fabrication costs, hindering the mass-scale development. Alternatively, the blazing effect has been exploited to provide remarkably high directionalities, relying on standard deep and shallow etch depths. Here, we report on the first experimental demonstration of an ultra-directional L-shaped fiber-chip grating coupler fabricated on 300 mm SOI wafer using 193-nm deep-ultraviolet lithography. The grating coupler is realized on a 300-nm-thick Si layer, combining standard full (300 nm) and shallow (150 nm) etch steps in an L-shaped arrangement. This approach yields a remarkably high grating directionality up to 98%. A single-step subwavelength-engineered transition provides an eight-fold reduction of the reflectivity, from ~8% to ~1%. We experimentally demonstrate a coupling efficiency of -2.7 dB, with a 3-dB bandwidth of 62 nm. These results open a new route towards exploiting the blazing effect for the large-volume realization of high-efficiency fiber-chip grating couplers in the low-cost 300 mm SOI photonic platform.

Paper Details

Date Published: 14 March 2018
PDF
Proc. SPIE 10535, Integrated Optics: Devices, Materials, and Technologies XXII, 105350W (14 March 2018); doi: 10.1117/12.2290584
Show Author Affiliations
Carlos A. Alonso-Ramos, Ctr. de Nanosciences et de Nanotechnologies (France)
Daniel Benedikovich, Ctr. de Nanosciences et de Nanotechnologies (France)
Diego Pérez-Galacho, Ctr. de Nanosciences et de Nanotechnologies (France)
Sylvain Guerber, STMicroelectronics (France)
Vladyslav Vakarin, Ctr. de Nanosciences et de Nanotechnologies (France)
Guillaume Marcaud, Ctr. de Nanosciences et de Nanotechnologies (France)
Xavier Le Roux, Ctr. de Nanosciences et de Nanotechnologies (France)
Eric Cassan, Ctr. de Nanosciences et de Nanotechnologies (France)
Delphine Marris-Morini, Ctr. de Nanosciences et de Nanotechnologies (France)
Pavel Cheben, National Research Council Canada (Canada)
Frédéric Boeuf, STMicroelectronics (France)
Charles Baudot, STMicroelectronics (France)
Laurent Vivien, Ctr. de Nanosciences et de Nanotechnologies (France)


Published in SPIE Proceedings Vol. 10535:
Integrated Optics: Devices, Materials, and Technologies XXII
Sonia M. García-Blanco; Pavel Cheben, Editor(s)

© SPIE. Terms of Use
Back to Top