InP-based membrane photodetectors on Si photonic circuitry

The work presented in this thesis is about indium phosphide (InP) based photodetectors for use in optical interconnections on silicon (Si) integrated circuits (ICs). The motivation for this work comes from the bottleneck expected at the interconnect level for future generation electronic ICs: with the technology scaling down and the signal switching frequency increasing, three main issues are predicted for the complementary metal-oxide semiconductor (CMOS) ICs, namely signal propagation delay, power consumption and integration density. Electrical interconnects (EIs) strongly limit these characteristics and a promising solution is given by replacing EIs with optical interconnects (OIs). The implementation of intra-chip and chip-to-chip OIs requires the use of photonic integrated circuit (PIC) technology. The integration of optical sources, waveguides and detectors forming a photonic interconnect layer on top of the CMOS circuitry provides bandwidth increase, immunity to electromagnetic (EM) noise and reduction in power consumption. This solution was investigated within this work, which focuses on the detector part. InP-based membrane photodetectors were realized on InP dies bonded on Si and CMOS wafers, on top of which passive Si and Si3N4 photonic circuitry had been defined. This approach combines the advantages of high quality Si-based passive circuits with the excellent properties of InP-based components for light generation and detection. The technology used for the InP device fabrication is compatible with wafer scale processing steps, assuring compatibility towards future generation electronic ICs. The major results of this work are summarized as follows: InP membrane couplers and detectors were successfully fabricated on Si and Si3N4 photonic circuits. Experimental results show working active and passive devices, namely: passive Si photonic components (waveguides, MMIs, (de)-multiplexers), InP membrane couplers, InP-based detectors and heterogeneously integrated multiwavelength receivers. A working laser-to-detector integrated optical link on Si was successfully demonstrated. This work was carried out with the support of the European project IST-PICMOS and of the Dutch Ministry of Economic Affairs through the Smartmix Memphis project

Indium phosphide based membrane photodetector for optical interconnects on silicon

We have designed, fabricated and characterized an InP-based membrane photodetector on an SOI wafer containing a Si-wiring photonic circuit. New results on RF characterization up to 20 GHz are presented. The detector fabrication is compatible with wafer scale processing steps, guaranteeing compatibility towards future generation electronic IC processing

InP/InGaAs photodetector on SOI photonic circuitry

We present an InP-based membrane p-i-n photodetector on a silicon-on-insulator sample containing a Si-wiring photonic circuit that is suitable for use in optical interconnections on Si integrated circuits (ICs). The detector mesa footprint is 50 µm2, which is the smallest reported to date for this kind of device, and the junction capacitance is below 10 fF, which allows for high integration density and low dynamic power consumption. The measured detector responsivity and 3-dB bandwidth are 0.45 A/W and 33 GHz, respectively. The device fabrication is compatible with wafer-scale processing steps, guaranteeing compatibility toward future-generation electronic IC processing

InGaAs/InP membrane photodetector bonded on silicon

We present the design, fabrication and characterization of a compact photodetector suitable for photonic interconnections on electronic ICs. In our approach, the InP-based optical sources and detectors are linked via Si photonic waveguides in an interconnection layer on top of the CMOS circuitry. The photonic device processing is compatible with Si wafer scale fabrication steps, which guarantees compatibility with future ICs manufacture. The detector maskes use of an InP membrane waveguide to couple the light out of the interconnection layer and carry it towards the absorption region. A responsivity of 0.45 A/W and a rather flat frequency response in the 0-20 GHz range were measured

InP-based membrane photodetectors on Si photonic circuitry

The work presented in this thesis is about indium phosphide (InP) based photodetectors for use in optical interconnections on silicon (Si) integrated circuits (ICs). The motivation for this work comes from the bottleneck expected at the interconnect level for future generation electronic ICs: with the technology scaling down and the signal switching frequency increasing, three main issues are predicted for the complementary metal-oxide semiconductor (CMOS) ICs, namely signal propagation delay, power consumption and integration density. Electrical interconnects (EIs) strongly limit these characteristics and a promising solution is given by replacing EIs with optical interconnects (OIs). The implementation of intra-chip and chip-to-chip OIs requires the use of photonic integrated circuit (PIC) technology. The integration of optical sources, waveguides and detectors forming a photonic interconnect layer on top of the CMOS circuitry provides bandwidth increase, immunity to electromagnetic (EM) noise and reduction in power consumption. This solution was investigated within this work, which focuses on the detector part. InP-based membrane photodetectors were realized on InP dies bonded on Si and CMOS wafers, on top of which passive Si and Si3N4 photonic circuitry had been defined. This approach combines the advantages of high quality Si-based passive circuits with the excellent properties of InP-based components for light generation and detection. The technology used for the InP device fabrication is compatible with wafer scale processing steps, assuring compatibility towards future generation electronic ICs. The major results of this work are summarized as follows: InP membrane couplers and detectors were successfully fabricated on Si and Si3N4 photonic circuits. Experimental results show working active and passive devices, namely: passive Si photonic components (waveguides, MMIs, (de)-multiplexers), InP membrane couplers, InP-based detectors and heterogeneously integrated multiwavelength receivers. A working laser-to-detector integrated optical link on Si was successfully demonstrated. This work was carried out with the support of the European project IST-PICMOS and of the Dutch Ministry of Economic Affairs through the Smartmix Memphis project

InP Photonic integrated circuit with on-chip monitors for optical beam steering

Optical beam steering controlled by an array of phase shifters from an InP photonic integrated circuit has been demonstrated with the help from on-chip monitors

Comparison of optical passive integrated devices based on three materials for optical clock distribution

We report different passive integrated devices characterization based on three materials (SOI, a-Si:H and SiNx) for the realization of an optical compact link compatible with CMOS technology. The low level of losses obtained on the passive elementary components for the optical link (strip guides, micro bend and MMI beam splitter) shows the feasibility of photonic integration on silicon using amorphous silicon

InGaAs/InP membrane photodetector bonded on silicon

We present the design, fabrication and characterization of a compact photodetector suitable for photonic interconnections on electronic ICs. In our approach, the InP-based optical sources and detectors are linked via Si photonic waveguides in an interconnection layer on top of the CMOS circuitry. The photonic device processing is compatible with Si wafer scale fabrication steps, which guarantees compatibility with future ICs manufacture. The detector maskes use of an InP membrane waveguide to couple the light out of the interconnection layer and carry it towards the absorption region. A responsivity of 0.45 A/W and a rather flat frequency response in the 0-20 GHz range were measured

First integrated combiner based on self-switching in quantum dots

We demonstrate all-optical switching in quantum dots (QDs). The switching is studied in an integrated optical combiner circuit. This is a Mach–Zehnder interferometer with an unequal power distribution over the branches. The refractive index is intensity dependent in the branches due to the QDs. Large all-optical nonlinearities are measured. This device is aimed to avoid an unwanted 3-dB loss, fundamental in passive optical splitters