4,135 research outputs found
Performance of electronic dispersion compensator for 10Gb/s multimode fiber links
In high-speed optical links, electronic compensation circuits can be utilized to greatly improve the data transmission performance limited by fiber dispersion. In this paper, we develop a full link model, including
multimode fibers, optical/electronics/optical components, clock-and-data recovery and electronic compensation circuits. The performance of various electronic compensation techniques, such as feed-forward equalizer and decision feedback equalizer for optical multimode fiber is investigated and numerically evaluated. Finally, a comparison of the performance of each compensation techniques and a proposal of optimal equalizer circuit implementation, achieving a 10-Gb/s transmission over 1-km standard multimode fiber are presented
Dimensioning the future pan-European optical network with energy efficiency considerations
This paper studies the overall energy consumption of a pan-European optical transport network for three different time periods: today and in five and ten years from now. In each time period the pan-European network was dimensioned using traffic predictions based on realistic data generated by the optical networking roadmap developed in the framework of the European project Building the Future Optical Network in Europe-BONE. A wavelength routed wavelength division multiplexed optical network based on either transparent or opaque node architectures was examined considering exclusively either 10 Gbit/s or 40 Gbit/s per channel data rates. The results manifest that transparent optical networking technologies are expected to provide significant energy savings of the order of 35% to 55%. It was also shown that the migration towards higher data rates, i.e., from 10 Gbit/s to 40 Gbit/s, is assisting in improving the overall energy efficiency of the network
Devices and architectures for large scale integrated silicon photonics circuits
We present DWDM nanophotonics architectures based on microring resonator modulators and detectors. We focus on two implementations: an on chip interconnect for multicore processor (Corona) and a high radix network switch (HyperX). Based on the requirements of these applications we discuss the key constraints on the photonic circuits' devices and fabrication techniques as well as strategies to improve their performance
Multi-phase semicrystalline microstructures drive exciton dissociation in neat plastic semiconductors
The optoelectronic properties of macromolecular semiconductors depend
fundamentally on their solid-state microstructure. For example, the
molecular-weight distribution influences polymeric- semiconductor properties
via diverse microstructures; polymers of low weight-average molecular weight
(Mw) form unconnected, extended-chain crystals, usually of a paraffinic
structure. Because of the non-entangled nature of the relatively short-chain
macromolecules, this leads to a polycrystalline, one-phase morphology. In
contrast, with high-Mw materials, where average chain lengths are longer than
the length between entanglements, two-phase morphologies, comprised of
crystalline moieties embedded in largely unordered (amorphous) regions, are
obtained. We investigate charge photogeneration processes in neat regioregular
poly(3-hexylthiophene) (P3HT) of varying Mw by means of time-resolved
photoluminescence (PL) spectroscopy. At 10 K, PL originating from recombination
of long-lived charge pairs decays over microsecond timescales. Both the
amplitude and decay rate distribution depend strongly on Mw. In films with
dominant one-phase chain-extended microstructures, the delayed PL is suppressed
as a result of a diminished yield of photoinduced charges, and its decay is
significantly faster than in two-phase microstructures. However, independent of
Mw, charge recombination regenerates singlet excitons in torsionally disordered
chains forming more strongly coupled photophysical aggregates than those in the
steady-state ensemble, with delayed PL lineshape reminiscent of that in
paraffinic morphologies at steady state. We conclude that highly delocalized
excitons in disordered regions between crystalline and amorphous phases
dissociate extrinsically with yield and spatial distribution that depend
intimately upon microstructure.Comment: 19 pages, 4 figure
Characterisation of a reconfigurable free space optical interconnect system for parallel computing applications and experimental validation using rapid prototyping technology
Free-space optical interconnects (FSOIs) are widely seen as a potential solution to
present and future bandwidth bottlenecks for parallel processing applications.
This thesis will be focused on the study of a particular FSOI system called Optical
Highway (OH). The OH is a polarised beam routing system which uses Polarising
Beam Splitters and Liquid Crystals (PBS/LC) assemblies to perform reconfigurable
interconnection networks. The properties of the OH make it suitable for implementing
different passive static networks.
A technology known as Rapid Prototyping (RP) will be employed for the first time in
order to create optomechanical structures at low cost and low production times. Off-theshelf
optical components will also be characterised in order to implement the OH.
Additionally, properties such as reconfigurability, scalability, tolerance to misalignment
and polarisation losses will be analysed. The OH will be modelled at three levels: node,
optical stage and architecture. Different designs will be proposed and a particular
architecture, Optimised Cut-Through Ring (OCTR), will be experimentally
implemented. Finally, based on this architecture, a new set of properties will be defined
in order to optimise the efficiency of the optical channels
Experimental Evaluation and Comparison of Time-Multiplexed Multi-FPGA Routing Architectures
Emulating large complex designs require multi-FPGA systems (MFS). However, inter-FPGA communication is confronted by the challenge of lack of interconnect capacity due to limited number of FPGA input/output (I/O) pins. Serializing parallel signals onto a single trace effectively addresses the limited I/O pin obstacle. Besides the multiplexing scheme and multiplexing ratio (number of inter-FPGA signals per trace), the choice of the MFS routing architecture also affect the critical path latency. The routing architecture of an MFS is the interconnection pattern of FPGAs, fixed wires and/or programmable interconnect chips. Performance of existing MFS routing architectures is also limited by off-chip interface selection. In this dissertation we proposed novel 2D and 3D latency-optimized time-multiplexed MFS routing architectures. We used rigorous experimental approach and real sequential benchmark circuits to evaluate and compare the proposed and existing MFS routing architectures. This research provides a new insight into the encouraging effects of using off-chip optical interface and three dimensional MFS routing architectures. The vertical stacking results in shorter off-chip links improving the overall system frequency with the additional advantage of smaller footprint area. The proposed 3D architectures employed serialized interconnect between intra-plane and inter-plane FPGAs to address the pin limitation problem. Additionally, all off-chip links are replaced by optical fibers that exhibited latency improvement and resulted in faster MFS. Results indicated that exploiting third dimension provided latency and area improvements as compared to 2D MFS. We also proposed latency-optimized planar 2D MFS architectures in which electrical interconnections are replaced by optical interface in same spatial distribution. Performance evaluation and comparison showed that the proposed architectures have reduced critical path delay and system frequency improvement as compared to conventional MFS. We also experimentally evaluated and compared the system performance of three inter-FPGA communication schemes i.e. Logic Multiplexing, SERDES and MGT in conjunction with two routing architectures i.e. Completely Connected Graph (CCG) and TORUS. Experimental results showed that SERDES attained maximum frequency than the other two schemes. However, for very high multiplexing ratios, the performance of SERDES & MGT became comparable
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