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Time-resolved terahertz spectroscopic studies were carried out on bulk InP to measure photoconductivity on the picosecond timescale. Comparison of the carrier multiplication quantum yields obtained with those of colloidal InP nanoparticles clearly demonstrate the potential benefit of InP nanoparticle-based next-generation solar cells.
It is envogue to consider how to incorporate various home devices such as set-top boxes into content delivery architectures using the Peer-to-Peer (P2P) paradigm. The hope is to enhance the efficiency of content delivery, e.g., in terms of reliability, availability, throughput, or to reduce the cost of the content delivery platform or to improve the end user experience. While it is easy to point out...
Next-generation optical access networks will deliver substantial benefits to consumers including a dedicated high-QoS access to bit rates of hundreds of Megabits per second. They must also deliver significant benefits to network owners/operators to justify the needed infrastructure investment expected to reach billions of Euros. Benefits to network owners/operators are expected to include reduced...
Today's access networks are still mainly based on copper cable infrastructure in the first mile. The geographic extension of conventional access service areas and with this also the structure of the access/aggregation network is mainly defined by the resistance of the copper lines - and thus the copper loop length - as well as by the switching capacity of the electro-mechanic telephone exchanges in...
Characterization techniques based on measuring the photocurrent of a solar cell under local illumination are introduced. Experiments on test structures and numerical simulations proof the applicability and reliability under realistic conditions and show technical limits.
The ultrafast carrier dynamics of Ge/SiGe quantum wells on Si substrate are investigated by pump-probe spectroscopy. Pronounced nonequilibrium effects in the relaxation dynamics and transient gain are observed and analyzed using a microscopic many-body theory.
In this paper a cost comparison of flexible and fixed fiber access network designs is presented. Different cost types are analyzed over a period of time and the impact of different penetration scenarios is investigated. The results show, that a fixed Optical Distribution Network design has significant cost advantages compared to a flexible design.
Ga(NAsP) multi quantum well heterostructures were grown pseudomorphically on exactly oriented (001) silicon substrates without the formation of misfit dislocations. Optical pumped lasing operation was observed at temperatures up to 125 K.
Ultrafast carrier dynamics of Ge/SiGe quantum wells grown on a Si substrate are investigated using pump-probe spectroscopy. Optical gain and population inversion are obtained on a femtosecond time scale. A microscopic theory supports the results.
Ultrafast carrier relaxation of Ge/SiGe quantum wells grown on a Si substrate are investigated using pump-probe spectroscopy. A nonthermal carrier distribution is observed. The corresponding inter- and intra-valley scattering times are deduced.
The increasing demand for higher bit rates in access networks requires fibre deployment closer to the customer since bit rates in copper based access networks are strictly limited by the length of the copper cables. Besides higher access bit rates optical access network technologies enable extended distances between the network terminal at the customer premise and the line port at the access node...
Nowadays silicon photonics gains more and more interest especially for the future architecture of Si based optoelectronic integrated circuits (OEI C). OEIC building blocks such a s modulators, detectors as well as light wave guides have been demonstrated in a down-scalable process technology. However, a commercial solution for the monolithic integration of long-term stable laser diodes has not been...
In this paper, we analyze a scenario, in which a hydrobot would be sent through the several kilometers thick ice layer of the Jovian Moon Europa, integrated in a melting probe, and once reaching the ocean, would perform a highly autonomous investigation of its habitability. The hydrobot would be either swimming or driving at the bottom of the ocean or the underside of the ice layer, equipped with...
We report lasing of optically pumped Ga(NAsP)/(BGa)(AsP) heterostructures grown lattice-matched on Si. Modal gain of up to 80 cm-1 is determined at 300 K and a distinct threshold behaviour and mode spectrum is observed up to 100 K.
Today's available fibre access technologies are based on point-to-point, GPON, EPON or active node solutions. This paper will focus on challenges in future access networks from an architectural, technological and economical point of view.
This paper reports on a FTTH field trial with GPON technology in the network of Deutsche Telekom AG. Focus of this trial was to gain practical experience regarding: GPON technology, fibre installation in existing ducts with micro duct technology, fibre cabling in customer buildings and impact on operational processes.
The energy consumption of FTTH network variants is compared with respect to the average access bit rate. The results show that passive optical networks are more energy efficient than point-to-point or active optical access networks.
Based on a model of a typical operator network we have compared the power consumption of different broadband access technologies and architectures especially DSL, FTTN + VDSL and FTTH. Even though power management improves the performance there is still clear advantage of FTTH with respect to energy efficiency.
The focus of the present study is the optical characterisation of the novel direct band gap material Ga(NAsP) monolithically grown on Si substrate. Ga(NAsP)/(BGa)(AsP) multi-quantum-well heterostructures (MQWHs) were deposited by low temperature metal organic vapour phase epitaxy (MOVPE) in a commercial reactor system on nominally exact (001) Si substrates. In order to realise III/V laser diode the...
The size of unified modeling language (UML) models used in practice is very large and ranges up to hundreds and thousands of classes. Querying of these models is used to support their quality assessment by information filtering and aggregating. For both, human cognition and automated analysis, there is a need for fast querying. In this context performance of model queries becomes an important issue...
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