1,721,073 research outputs found
Germanium on Silicon for Near-Infrared Light Sensing
No full textWe review near-infrared detectors in germanium grown on silicon. We discuss pn and pin photodiodes based on Ge deposited on Si by a number of techniques, including thermal evaporation; the optical and electronic characterization of Ge-on-Si heterostructures using various approaches to minimize the density of defects; and compatibility issues with standard fabrication processes for Si electronics. We describe in greater detail the most promising devices realized by us and operating either at normal incidence or in guided-wave geometries, with applications to high-speed optical receivers, as well as image sensors
A sensor for the optical detection of dangerous road condition
No full textWe present the design, realization and characterization of a sensor for the optical detection of hazardous road condition. The device exploits the radiation from a incoherent source to detect the polarized components of the light scattering from a rough surface and calculate a signal dependent on the surface state. We propose two distinct geometries, working with forward and backward scattering components, assessing the device performance in terms of reliability and compactness. In both cases, the sensor allows to discriminate potentially dangerous states like the presence of water (either wet surface or covered by a layer) or ice on an asphalt sample, in opposition to the dry surface representing a safe condition
Guided-wave near-infrared detector in polycrystalline germanium on silicon
No full textUsing a guided wave configuration, we demonstrate a novel polyGe-on-Si heterostructure photodetector realized on a silicon-on-insulator by a low deposition temperature process. Without further detector optimization, at 1.55 mu m we measured wall-plug responsivities as high as 15 mA/W with an effective responsivity in excess of 300 mA/W. Device operation was demonstrated up to 2.5 Gbit/s. (C) 2005 American Institute of Physics
Wavelength stabilizer for telecommunication lasers: Design and optimization
No full textWe introduce a novel method for the wavelength stabilization of semiconductor lasers for telecommunications. The approach is based on a wavelength-sensitive photodetector which, in a feedback system, generates an error signal apt to tune the source to the desired value. We extensively investigate the influence of various design parameters on performance figures such as tunability, steady-state error, and temperature dependence, as well as fabrication tolerances. The results are compared with standard specifications for wavelength-division-multiplexed optical communications with various channel spacings
Monolithic Integration of Near Infrared Ge Photodetectors with Si CMOS Readout Electronics
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