In Situ Calibration of Heterogeneous Acquisition Systems: The Monitoring System of a Photovoltaic Plant

This paper deals with the metrological management of an acquisition system that has been developed for monitoring an experimental photovoltaic (PV) plant. The acquisition system has been conceived for comparing the performance of different PV technologies and for verifying the nominal specifications of the PV modules. For these reasons, the traceability of the monitoring system has to be ensured, and therefore, it must be periodically calibrated. A remotely exercised procedure is proposed for the calibration of the acquisition system, which is based on a calibrator specifically designed for this application. This calibrator has the capability to act as a reference for heterogeneous quantities, including electrical quantities, temperature, and solar irradiance. The architecture of this calibrator is described, and experimental results for the preliminary characterization of the prototype are described

Electrically packaged silicon-organic hybrid (SOH) I/Q-modulator for 64 GBd operation

Silicon-organic hybrid (SOH) electro-optic (EO) modulators combine small footprint with low operating voltage and hence low power dissipation, thus lending themselves to on-chip integration of large-scale device arrays. Here we demonstrate an electrical packaging concept that enables high-density radio-frequency (RF) interfaces between on-chip SOH devices and external circuits. The concept combines high-resolution $\mathrm{Al_2O_3}$ printed-circuit boards with technically simple metal wire bonds and is amenable to packaging of device arrays with small on-chip bond pad pitches. In a set of experiments, we characterize the performance of the underlying RF building blocks and we demonstrate the viability of the overall concept by generation of high-speed optical communication signals. Achieving line rates (symbols rates) of 128 Gbit/s (64 GBd) using quadrature-phase-shiftkeying (QPSK) modulation and of 160 Gbit/s (40 GBd) using 16-state quadrature-amplitudemodulation (16QAM), we believe that our demonstration represents an important step in bringing SOH modulators from proof-of-concept experiments to deployment in commercial environments

Characterization and Performance Comparison of Low-Voltage, High-Speed, Push-Pull and traveling-wave Silicon Mach-Zehnder Modulators

The well-known power and memory walls are recognized as the current bottlenecks in computing performance, and with the increasing computational load of commonly run applications, it is necessary to nd ways to alleviate the issues presented by the aforementioned bottlenecks. It is therefore necessary to not focus solely on extracting performance improvement by way of changes to the processing architecture, but rather by holistically improving the computing platform, namely the communications backbone. This work focuses on the characterization and performance comparison of two families of optical data modulators, both fundamentally Mach{Zehnder modulators (MZMs); namely, a modulator with a Push-Pull (PP) modulation scheme, and another modulator with a Traveling-Wave Electrode (TWE) design, prioritizing the effects on high-speed performance. A number of operating conditions temperature, wavelength, bias voltage, and bit rate were varied to determine effects of modulator performance, measured in terms of DC performance characterization, bit error rate, electrical bandwidth, and power-penalty. Custom xtures were designed and fabricated to achieve long-term experimental stability, and software was written to accomplish long term experimentation; the con uence of the two resulted in a wealth of data for use in performance comparison. Despite the use of a push-pull modulation scheme, the devices using a traveling-wave electrode outperformed the push- pull modulators in almost all metrics, even at what was assumed to be a relatively low bit rate of 3 Gbps. This work then accentuates the importance of velocity and impedance matching, even at presumably low data rates, in spite of increased device fabrication complexity

High accuracy transportable selectable-Value High Dc Voltage Standard

À l'Institut national de recherche metrologique (INRIM) il a été développé un étalon de haute tension continue avec des valeurs sélectionnables de 10 V à 100 V pour compenser le manque d'étalons de haut niveau de tension continue d'une valeur supérieure à 10 V pour les comparaisons interlaboratoires de haut niveau. Il a été utilisé une nouvelle technique électronique de terre mobile. L'étalon développé a un bruit inférieur et il a la stabilité égal à celle des calibrateurs de tension continue ou multifonction de haut niveau largement utilisé dans les laboratoires d'étalonnage électriques; il a aussi une meilleure attitude à être transporté pour les comparaisons interlaboratoires. Le projet est extensible jusqu'à 1000 V

Silicon-Organic Hybrid (SOH) Mach-Zehnder Modulators for 100 Gbit/s On-Off Keying

Electro-optic modulators for high-speed on-off keying (OOK) are key components of short- and mediumreach interconnects in data-center networks. Besides small footprint and cost-efficient large-scale production, small drive voltages and ultra-low power consumption are of paramount importance for such devices. Here we demonstrate that the concept of silicon-organic hybrid (SOH) integration is perfectly suited for meeting these challenges. The approach combines the unique processing advantages of large-scale silicon photonics with unrivalled electro-optic (EO) coefficients obtained by molecular engineering of organic materials. In our proof-of-concept experiments, we demonstrate generation and transmission of OOK signals with line rates of up to 100 Gbit/s using a 1.1 mm-long SOH Mach-Zehnder modulator (MZM) which features a {\pi}-voltage of only 0.9 V. This experiment represents not only the first demonstration of 100 Gbit/s OOK on the silicon photonic platform, but also leads to the lowest drive voltage and energy consumption ever demonstrated at this data rate for a semiconductor-based device. We support our experimental results by a theoretical analysis and show that the nonlinear transfer characteristic of the MZM can be exploited to overcome bandwidth limitations of the modulator and of the electric driver circuitry. The devices are fabricated in a commercial silicon photonics line and can hence be combined with the full portfolio of standard silicon photonic devices. We expect that high-speed power-efficient SOH modulators may have transformative impact on short-reach optical networks, enabling compact transceivers with unprecedented energy efficiency that will be at the heart of future Ethernet interfaces at Tbit/s data rates

An Approach to Assess Solder Interconnect Degradation Using Digital Signal

Department of Human and Systems EngineeringDigital signals used in electronic systems require reliable data communication. It is necessary to monitor the system health continuously to prevent system failure in advance. Solder joints in electronic assemblies are one of the major failure sites under thermal, mechanical and chemical stress conditions during their operation. Solder joint degradation usually starts from the surface where high speed signals are concentrated due to the phenomenon referred to as the skin effect. Due to the skin effect, high speed signals are sensitive when detecting the early stages of solder joint degradation. The objective of the thesis is to assess solder joint degradation in a non-destructive way based on digital signal characterization. For accelerated life testing the stress conditions were designed in order to generate gradual degradation of solder joints. The signal generated by a digital signal transceiver was travelling through the solder joints to continuously monitor the signal integrity under the stress conditions. The signal properities were obtained by eye parameters and jitter, which represented the characteristics of the digital signal in terms of noise and timing error. The eye parameters and jitter exhibited significant increase after the exposure of the solder joints to the stress conditions. The test results indicated the deterioration of the signal integrity resulted from the solder joint degradation, and proved that high speed digital signals could serve as a non-destructive tool for sensing physical degradation. Since this approach is based on the digital signals used in electronic systems, it can be implemented without requiring additional sensing devices. Furthermore, this approach can serve as a proactive prognostic tool, which provides real-time health monitoring of electronic systems and triggers early warning for impending failure.ope