Authors: M. Araghchini, A. Khilo, C.W. Holzwarth, M.S. Dahlem, H.I. Smith, E.P. Ippen, F.X. Kärtner
Affilation: Massachusetts Institute of Technology, United States
Pages: 310 - 313
Keywords: integrated optics, couplers, integrated photonics
In silicon photonics, light sources are typically located off-chip and connected to the chip with optical fibers. The problem of efficient coupling between the fiber and a submicron waveguide is challenging because the mode areas can differ by up to three orders of magnitude. In this work, we demonstrate that it is possible to use a high index multimode waveguide with its lowest order mode matched to the fiber mode, which increases the range of materials usable for the coupler waveguide significantly. An inverse-taper coupler between a fiber and a SiNx-waveguide overclad with silicon oxide was fabricated. 1dB loss was measured for a 750µm-long device with a low-index multimode waveguide designed to match a 4.0µm fiber.