Bimodal grating coupler design on SOI technology for mode division multiplexing at 1550 nm.

In this paper, we evaluate by means of simulation and experimentally the simultaneous coupling of the LP01x-LP11ax fiber modes and the TE0-TE1 nanophotonic SOI waveguide modes using a grating coupler for a two-mode fiber at 1550 nm. Both the grating width (ranging from 10 mu m to 15 mu m) and the grating vertical profile have been considered in the design procedure. The optimum design (14 mu m width and 609 nm grating period) has been selected in terms of coupling efficiency (both LP01x-TE0 and LP11ax-TE1), compactness and tolerance to lateral misalignments between fiber and coupler. The LP01x-TE0 and LP11ax-TE1 modes achieved coupling efficiencies of 49% and 45%, respectively. (C) 2017 Optical Society of America under the terms of the OSA Open Access Publishing Agreement