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 1.55mum 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.

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

Compact metal grating couplers for efficient and broadband coupling between optical fibers and silicon-on-insulator waveguides are proposed and demonstrated. Simulation results for silver, gold, aluminum and copper grating couplers are presented. Using a uniform silver grating, coupling efficiencies are calculated as high as 60 % at a wavelength of 1.55 mum. Metal grating couplers require only one single etching or lift-off step and are therefore very easy to fabricate. As a proof of principle, a gold grating coupler for near-vertical fiber-to-waveguide coupling was fabricated using e-beam writing and lift-off, demonstrating 34 % coupling efficiency and a 1 dB-bandwidth of 40 nm. Measurement data and simulation results are in good agreement.