Intra- Datacenter Challenges; System Perspective

Invited presentation at ECOC Sunday workshop with title: Data Center Networks: Meeting the emerging requirements for capacity, cost, energy consumption and reac

Design and experimental verification of a transimpedance amplifier for 64-Gb/s PAM-4 optical links

The use of four-level pulse-amplitude modulation (PAM-4) has emerged as a solution to increase the serial rate in short-range optical links, offering twice the data throughput but requiring similar bandwidth as on-off keying. However, the receiver design should take into account the increased susceptibility of PAM-4 to noise, intersymbol interference, and nonlinearity. This papers explores these challenges, and details the design of a transimpedance amplifier (TIA) for 64-Gb/s PAM-4 optical links. The TIA was implemented in 0.13-mu m SiGe BiCMOS, and has a power consumption of 180 mW. It contains a digital gain controller, which allows switching between four gain modes, to tradeoff sensitivity against linearity. Bit error rate (BER) measurements show that the dynamic range is significantly extended: Optical modulation amplitudes between -7 dBm and at least -0.2 dBm yield a BER lower than 10(-3)

Resolving the Mystery of the Elusive Peak: Negative Differential Resistance in Redox Proteins

Vertical molecular transistors are used to explain the nonconformal electron transfer results obtained for redox proteins. The transport characteristics of a negative differential resistance peak as appears in the transport data of azurin and its nonredox derivative are explored. A correlation between the peak and its redox center is demonstrated

DNA-nanoparticle assemblies go organic: Macroscopic polymeric materials with nanosized features

<p>Abstract</p> <p>Background</p> <p>One of the goals in the field of structural DNA nanotechnology is the use of DNA to build up 2- and 3-D nanostructures. The research in this field is motivated by the remarkable structural features of DNA as well as by its unique and reversible recognition properties. Nucleic acids can be used alone as the skeleton of a broad range of periodic nanopatterns and nanoobjects and in addition, DNA can serve as a linker or template to form DNA-hybrid structures with other materials. This approach can be used for the development of new detection strategies as well as nanoelectronic structures and devices.</p> <p>Method</p> <p>Here we present a new method for the generation of unprecedented <b><it>all-organic</it></b> conjugated-polymer nanoparticle networks guided by DNA, based on a hierarchical self-assembly process. First, microphase separation of amphiphilic block copolymers induced the formation of spherical nanoobjects. As a second ordering concept, DNA base pairing has been employed for the controlled spatial definition of the conjugated-polymer particles within the bulk material. These networks offer the flexibility and the diversity of soft polymeric materials. Thus, simple chemical methodologies could be applied in order to tune the network's electrical, optical and mechanical properties.</p> <p>Results and conclusions</p> <p>One- two- and three-dimensional networks have been successfully formed. Common to all morphologies is the integrity of the micelles consisting of DNA block copolymer (DBC), which creates an all-organic engineered network.</p