Electrically induced Bragg Reflectors in In/InGaAsP waveguides as ultrafast optoelectronic modulators

In this paper, with the help of numerical simulations, we show how it is possible to create a Distributed Bragg Reflector by electrically inducing periodical refractive index variations in unperturbed III-V rib-waveguides to design different kind of devices. This approach allows to induce the optoelectronic devices by a suitable reconfiguration of the potential applied to the electrode matrix, i.e. to have a defined routing/switching matrix, or, for dynamic applications, realize intensity modulators, capable of reaching a theoretical 40 GHz switching speed

A comprehensive study of the short-circuit ruggedness of silicon carbide power MOSFETs

The behavior of Silicon Carbide Power MOSFETs under stressful short circuit conditions is investigated in this paper. Illustration of two different short-circuit failure phenomena for Silicon Carbide Power MOSFETs are thoroughly reported. Experimental evidences and TCAD electro-thermal simulations are exploited to describe and discriminate the failure sources. Physical causes are finally investigated and explained by means of properly calibrated numerical investigations, and are reported along with their effects on devices short-circuit capability

INFRARED THERMOGRAPHY APPLIED TO POWER ELECTRON DEVICES INVESTIGATION

The aim of this paper is to give a presentation of the principal applications of Infrared Thermography for analysis and testing of electron devices. Even though experimental characterization could be carried out on almost any electronic devices and circuits, here IR Thermography for investigation of power semiconductor devices is presented. Different examples of functional and failure analysis in both transient and lock-in modes will be reported

Radiation hard polyimide-coated FBG optical sensors for relative humidity monitoring in the CMS experiment at CERN

This work investigates the performance and the radiation hardness capability of optical thermo-hygrometers based on Fibre Bragg Gratings (FBG) for humidity monitoring in the Compact Muon Solenoid (CMS), one of the four experiments running at CERN in Geneva. A thorough campaign of characterization was performed on 80 specially produced Polyimide-coated RH FBG sensors and 80 commercial temperature FBG sensors. Sensitivity, repeatability and accuracy were studied on the whole batch, putting in evidence the limits of the sensors, but also showing that they can be used in very dry conditions. In order to extract the humidity measurements from the sensor readings, commercial temperature FBG sensors were characterized in the range of interest. Irradiation campaigns with ionizing radiation (gamma-rays from a Co-60 source) at incremental absorbed doses (up to 210 kGy for the T sensors and up to 90 kGy for the RH sensors) were performed on sample of T and RH-Sensors. The results show that the sensitivity of the sensors is unchanged up to the level attained of the absorbed dose, while the natural wavelength peak of each sensor exhibits a radiation-induced shift (signal offset). The saturation properties of this shift are discussed

Minimal information for studies of extracellular vesicles 2018 (MISEV2018):a position statement of the International Society for Extracellular Vesicles and update of the MISEV2014 guidelines

The last decade has seen a sharp increase in the number of scientific publications describing physiological and pathological functions of extracellular vesicles (EVs), a collective term covering various subtypes of cell-released, membranous structures, called exosomes, microvesicles, microparticles, ectosomes, oncosomes, apoptotic bodies, and many other names. However, specific issues arise when working with these entities, whose size and amount often make them difficult to obtain as relatively pure preparations, and to characterize properly. The International Society for Extracellular Vesicles (ISEV) proposed Minimal Information for Studies of Extracellular Vesicles (“MISEV”) guidelines for the field in 2014. We now update these “MISEV2014” guidelines based on evolution of the collective knowledge in the last four years. An important point to consider is that ascribing a specific function to EVs in general, or to subtypes of EVs, requires reporting of specific information beyond mere description of function in a crude, potentially contaminated, and heterogeneous preparation. For example, claims that exosomes are endowed with exquisite and specific activities remain difficult to support experimentally, given our still limited knowledge of their specific molecular machineries of biogenesis and release, as compared with other biophysically similar EVs. The MISEV2018 guidelines include tables and outlines of suggested protocols and steps to follow to document specific EV-associated functional activities. Finally, a checklist is provided with summaries of key points

ALL-SILICON OPTICAL TEMPERATURE SENSOR BASED ON MULTI-MODE INTERFERENCE

In this paper we present a novel approach to temperature sensing with optoelectronic devices which relies on the usage of bare silicon as the transducing material. The device is composed by a single mode input waveguide, a MMI region where a number of higher order modes is also allowed to propagate and two output waveguides. The refractive index variation in the MMI section due to temperature shifts induces different phase velocities of the various propagating modes. The position of the input and output waveguides together with the length and width of the MMI section are chosen in order to maximize the sensitivity of the device. Analytical calculations are presented together with BPM simulations aimed to the maximization of the sensitivity of the sensor as a function of its geometries

An ultrafast optical modulator based on a SiGe HBT

In this paper a novel configuration of optical modulator is presented. It combines the effect of fast electron-hole plasma injection obtained with a SiGe HBT together with the usage of a distributed Bragg reflector. Numerical simulations performed on a non-optimized device shows that the presence of the SiGe HBT enhances significantly the performances obtained with a similar device realized with and all-silicon pin diode. Switching speed higher than 1 GHZ have been numerically simulated