P. De Heyn

-1 V bias 67GHz bandwidth Si-contacted germanium waveguide p-i-n photodetector for optical links at 56 Gbps and beyond

We demonstrate a 67 GHz bandwidth silicon-contacted germanium waveguide p-i-n photodetector operating at -1 V with 6.8 fF capacitance. The dark current is below 4 nA. The responsivity is 0.74 A/W at 1550 nm and 0.93 A/W at 1310 nm wavelength. 56 Gbps on-off-keying data reception is demonstrated with clear open eye diagrams in both the C-band and O-band.

Silicon-on-Insulator All-Pass Microring Resonators Using a Polarization Rotating Coupling Section

We propose a novel microring resonator concept that uses a polarization rotating asymmetrical directional coupler. The quasi-transverse electric polarized mode in the bus waveguide is used to excite the quasi-transverse magnetic (TM) polarized mode in the microring. This enables the realization of microrings with a high quality factor due to the lower scattering loss of the quasi-TM polarized mode. We demonstrate the operation principle with two all-pass microrings with radius 30 μm, working in the critically coupled regime with a quality factor of 31 000 and in the under-coupled regime with a quality factor of 125 000.

Silicon-on-Insulator Nanowire Resonators for Compact and Ultra-High Speed All-Optical Wavelength Converters

We present the development of application-specific silicon-on-insulator SOI nanowire ring and racetrack resonators designed to assist semiconductor optical amplifier (SOA)-based all-optical wavelength conversion. We demonstrate the fabrication of fix resonance racetrack resonators exhibiting coupling gaps as low as 160 nm and tunable ring resonators with coupling gaps <; 90 nm. The resonators are cascaded after commercial 40 Gb/s SOAs to realize chirp filtering of the optical data signals through high-resolution spectral sampling. We experimentally demonstrate inverted and non-inverted SOI resonator-assisted all-optical wavelength conversion at 40 Gb/s and 160 Gb/s with power penalties <; 3 dB.

Active Components for 50 Gb/s NRZ-OOK Optical Interconnects in a Silicon Photonics Platform

We present active components developed in imecs silicon photonics platform that enable 50-Gb/s non-return-to-zero operation using CMOS compatible voltages.

Dark current analysis in high-speed germanium p-i-n waveguide photodetectors

We present a dark current analysis in waveguide-coupled germanium vertical p-i-n photodetectors. In the analysis, a surface leakage current and a bulk leakage current were separated, and their activation energies were extracted. The surface leakage current originating from the minority carrier generation on the Ge layer sidewalls, governed by the Shockley-Read-Hall process and enhanced by the trap-assisted-tunneling process, was identified as the main contribution to the dark current of vertical p-i-n photodiodes at room temperature. The behavior of this surface leakage current as a function of temperature and reverse bias voltage is well reproduced by using the Hurckx model for trap-assisted-tunneling.

The BOOM Project: Towards 160 Gb/s Packet Switching Using SOI Photonic Integrated Circuits and Hybrid Integrated Optical Flip-Flops

We present a 160 Gb/s optical packet switching architecture that performs label detection and packet wavelength con- version using photonic components integrated on silicon-on-insulator (SOI) waveguide boards. For label detection, we report the fabrication of a 4-channel tunable, second-order microring resonator demultiplexer using the SOI nanowire waveguide platform. For all-optical wavelength conversion we report the integration and packaging of a cascaded SOI delay interferometer (DI) structure using SOI rib waveguides. Both components were assembled with an optical flip-flop to enable 160 Gb/s optical packet switching. The power penalty after the wavelength conversion process was ~4.5 dB with error performance well above the FEC limit. This work is part of the European ICT-BOOM project which aims at building a Tb/s photonic router using hybrid and heterogeneous integration on SOI substrates. The preliminary results reported here is the initial step before the final project demonstrator.

100-Gbps RZ Data Reception in 67-GHz Si-Contacted Germanium Waveguide p-i-n Photodetectors

We demonstrate 100-Gbps silicon-contacted germanium waveguide p-i-n photodetectors integrated on imecs silicon photonics platform. The performance of 14 and 20 μm long devices is compared. The responsivity of the devices is 0.74 and 0.92 A/W at 1550 nm, respectively.

25-Gb/s 1310-nm Optical Receiver Based on a Sub-5-V Waveguide-Coupled Germanium Avalanche Photodiode

We demonstrate low-voltage waveguide-coupled germanium avalanche photodetectors (APDs) with a (wafer-scale mean) gain×bandwidth product of 140 GHz at -5 V by utilizing a 185-nm-thick Ge layer. An optical receiver based on such an APD operating up to 25 Gb/s is demonstrated.

Silicon-on-Insulator polarization rotating micro-ring resonator

We propose a novel micro-ring resonator which uses quasi-TE polarized light in the bus waveguide to excite the quasi-TM polarized modes in a micro-ring. An all-pass filter is demonstrated on Silicon-on-Insulator.

Real-time 100 Gb/s NRZ-OOK transmission with a silicon photonics GeSi electro-absorption modulator

We demonstrate single-wavelength, serial and real-time 100 Gb/s NRZ-OOK transmission over 500 m SSMF with a GeSi EAM implemented on a silicon photonics platform. The device was driven with 2 Vpp without 50 Ω termination, allowing a low-complexity solution for 400 GbE short-reach optical interconnects.