Frederik Van Laere

Grating Couplers for Coupling between Optical Fibers and Nanophotonic Waveguides

Nanophotonic waveguides and components are promising for use in the large-scale integration of photonic circuits. Coupling light between nanophotonic waveguides and a single-mode fiber is an important problem and many different solutions have been proposed and demonstrated in recent years. In this paper, we discuss a grating coupler approach. Grating couplers can be placed anywhere on a circuit and can easily be integrated. We have experimentally demonstrated >30% coupling efficiency with a 1 dB bandwidth of 40 nm on standard wafers. Theoretically, the coupling efficiency can be improved to >90% using an optimized grating design and layer stack. The fabrication of the couplers in silicon-on-insulator and in indium phosphide membranes is also discussed.

Efficient, broadband and compact metal grating couplers for silicon-on-insulator waveguides.

Metal grating couplers for Silicon-on-Insulator waveguides are proposed. A silver grating coupler with 33% coupling efficiency is designed. A gold grating coupler prototype is fabricated using Focused Ion Beams demonstrating over 10% coupling efficiency.

Coupling mechanisms for a heterogeneous silicon nanowire platform

We discuss different mechanisms for coupling light from nanophotonic silicon waveguides to different types of materials added on top of these waveguides for enhancing the functionality of these waveguides. We consider diffractive coupling, evanescent coupling, adiabatic coupling and coupling to an overlay and illustrate these with recent experimental and modelling results.

Integration of grating couplers with a compact photonic crystal demultiplexer on an InP membrane

We demonstrate the integration of a 30% efficient grating coupler with a compact photonic crystal wavelength demultiplexer (DeMUX). The DeMUX has seven output channels that are spaced 10 nm apart and is aimed at coarse WDM applications. The integrated devices are realized on a high-index-contrast InP membrane using a simple benzocyclobutene wafer bonding technique. Cross talks of -10 to -12 dB for four channels 20 nm apart are obtained without optimization.

High contrast reflection modulation near 1.55μm in InP 2D photonic crystals on silicon wafer

We report on reflection modulation results near 1.55 mum in InP-based two-dimensional photonic crystals. The fabrication technology uses a polymeric bonding technique to integrate the InP thin-slab onto a Silicon wafer. Reflectivity modulation greater than 90% is obtained by pumping at 810 nm with optical excitation densities of 15 muJ/cm(2). The resulting optical broadband modulation is based on the saturation of absorption of InGaAs quantum wells at a photonic mode frequency tunable by lithography.

High Index-Contrast Silicon-On-Insulator Nanophotonics

We will present recent progress in several devices based on silicon-on-insulator nanophotonics using deep-UV lithography. We will report on high efficiency grating couplers, ultra-compact arrayed waveguide gratings and ring-resonator based biosensors

Planar focusing lens grating for vertical coupling on 2D photonic crystal slab waveguide

Planar focusing lens gratings are investigated in order to realize an efficient coupling from an optical fiber to a two-dimensional photonic crystal slab waveguide. The optimal gratings exhibit the calculated coupling efficiency of 34%

III-V/Silicon Photonics: Technology and Integrated Devices

III-V/Silicon photonics comprises the heterogeneous integration of a III-V layer on top of an SOI waveguide circuit. We elaborate on the bonding technology used and on the fabrication of III-V/Silicon integrated circuits.