We propose the design of a composite device structure with germanium-based (Ge-based) waveguide photodetectors integrated with grating couplers on a silicon-on-insulator platform. The finite-difference time-domain method is used to establish simulation models and optimize the design of the waveguide detector and grating coupler. For the grating coupler, by adjusting the size parameters to the optimal value and combining the advantages of the nonuniform grating and the Bragg reflector structure, the peak coupling efficiency reaches 85% at 1550 nm and 75.5% at 2000 nm, which is, respectively, 31.3% and 14.6% higher than that of uniform grating. For the waveguide detector, a germanium-tin (GeSn) alloy was introduced to replace Ge as the active absorption layer at 1550 and 2000 nm, which not only broadened the detection range and significantly improved the light absorption of the detector but also realized the near-complete light absorption of the GeSn alloy when the device length was 10 µm. These results make it possible to miniaturize the device structure of Ge-based waveguide photodetectors.
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http://dx.doi.org/10.1364/AO.488145 | DOI Listing |
Germanium-on-insulator (GOI) has emerged as a novel platform for Ge-based electronic and photonic applications. Discrete photonic devices, such as waveguides, photodetectors, modulators, and optical pumping lasers, have been successfully demonstrated on this platform. However, there is almost no report on the electrically injected Ge light source on the GOI platform.
View Article and Find Full Text PDFWe propose the design of a composite device structure with germanium-based (Ge-based) waveguide photodetectors integrated with grating couplers on a silicon-on-insulator platform. The finite-difference time-domain method is used to establish simulation models and optimize the design of the waveguide detector and grating coupler. For the grating coupler, by adjusting the size parameters to the optimal value and combining the advantages of the nonuniform grating and the Bragg reflector structure, the peak coupling efficiency reaches 85% at 1550 nm and 75.
View Article and Find Full Text PDFGermanium (Ge) is an attractive material for monolithic light sources on a silicon chip. Introduction of tensile strain using a silicon nitride (SiN) stressor is a promising means for Ge-based light sources due to the enhancement of direct band gap recombination. We propose a device structure that enables current injection from a silicon-on-insulator (SOI) diode to a Ge waveguide with a SiN stressor formed by a simple fabrication process.
View Article and Find Full Text PDFGermanium (Ge)-based photodetectors have become one of the mainstream components in photonic-integrated circuits (PICs). Many emerging PIC applications require the photodetectors to have high detectivity and low power consumption. Herein, we demonstrate high-detectivity Ge vertical p-i-n photodiodes on an in-situ heavily arsenic (As)-doped Ge-on-Si platform.
View Article and Find Full Text PDFHigh-performance GeSn multiple-quantum-well (MQW) photodiode is demonstrated on a 200 mm Ge-on-insulator (GeOI) photonics platform for the first time. Both GeSn MQW active layer stack and Ge layer (top Ge layer of GeOI after bonding) were grown using a single epitaxy step on a standard (001)-oriented Si substrate (donor wafer) using a reduced pressure chemical vapor deposition (RPCVD). Direct wafer bonding and layer transfer technique were then employed to transfer the GeSn MQW device layers and Ge layer to a 200 mm SiO-terminated Si handle substrate.
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