Jonathan Schrauwen

Compact and Highly Efficient Grating Couplers Between Optical Fiber and Nanophotonic Waveguides

We present high-efficiency grating couplers for coupling between a single-mode fiber and nanophotonic waveguides, fabricated both in silicon-on-insulator (SOI) and InP membranes using BenzoCycloButene wafer bonding. The coupling efficiency is substantially increased by adding a gold bottom mirror to the structures. The measured coupling efficiency to fiber is 69% for SOI grating couplers and 56% for bonded InP membrane grating couplers

Compact Focusing Grating Couplers for Silicon-on-Insulator Integrated Circuits

We report experimental results on compact and broadband focusing grating couplers, both in silicon-on-insulator (SOI) and gold on SOI. An eight-fold length reduction of the coupling structure from fiber to photonic wire in SOI, as compared to a linear grating and adiabatic taper, is obtained, without performance penalty. A proof of principle is given for a focusing grating coupler in gold on SOI, with 20% fiber-to-focus efficiency.

Trimming of silicon ring resonator by electron beam induced compaction and strain

Silicon is becoming the preferable platform for future integrated components, mostly due to the mature and reliable fabrication capabilities of electronics industry. Nevertheless, even the most advanced fabrication technologies suffer from non-uniformity on wafer scale and on chip scale, causing variations in the critical dimensions of fabricated components. This is an important issue since photonic circuits, and especially cavities such as ring resonators, are extremely sensitive to these variations. In this paper we present a way to circumvent these problems by trimming using electron beam induced compaction of oxide in silicon on insulator. Volume compaction of the oxide cladding causes both changes in the refractive index and creates strain in the silicon lattice. We demonstrate a resonance wavelength red shift 4.91 nm in a silicon ring resonator.

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.

Focused-Ion-Beam Fabrication of Slanted Grating Couplers in Silicon-on-Insulator Waveguides

We have designed and fabricated an efficient grating coupler for coupling light between optical fibers and silicon-on-insulator waveguides. The coupler consists of 88-nm-wide slits, etched at an angle of 58deg to the surface normal. They are defined by direct etching with a focused ion beam, using iodine gas and an alumina hard mask. The measured efficiency is 46%

Compact grating couplers between optical fibers and Silicon-on-Insulator photonic wire waveguides with 69% coupling efficiency

We present efficient, compact and broadband grating couplers in Silicon-on-Insulator, for coupling between single mode fiber and nanophotonic waveguides. By adding a gold bottom mirror, the coupling efficiency is increased to 69%.

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.

Focused-ion-beam fabricated vertical fiber couplers on silicon-on-insulator waveguides

We fabricated grating couplers in silicon-on-insulator waveguides with focused-ion-beam. First devices were very lossy, but by using selective etchant and a hard mask we obtained efficiencies comparable to traditional fabrication techniques

Focused-Ion-Beam Fabrication of Slots in Silicon Waveguides and Ring Resonators

We present the focused-ion-beam fabrication of slots in existing silicon waveguides and racetrack resonators. The etch process was conducted with iodine enhancement and an alumina hard mask. We demonstrate a propagation loss of 100 dB/cm for slot waveguides and a Q value of 850 for slot racetrack resonators with bend radius of 6 mum.

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.