Comparison of 100 Gb/s Ethernet links using PAM-8, multi-pulse, and hybrid CAP-16/QAM-16 modulation schemes

A theoretical study compares 100 Gb/s Ethernet links and finds that multi-pulse and hybrid CAP-16/QAM-16 (PAM-8) schemes support transmission over 10 km (2 km) SMF. Multi-pulse and CAP-16/QAM-16 need 2× the number of arithmetic operations and 7× or 3× the number of filter taps respectively but exhibit reduced power dissipation compared with PAM-8.

Antimicrobial activity-specific to Gram-negative bacteria and immune modulation-mediated NF-kappa B and Sp1 of a medaka beta-defensin

Defensins are a group of cationic antimicrobial peptides which play an important role in the innate immune system by exerting their antimicrobial activity against pathogens. In this study, we cloned a novel beta-defensin cDNA from medaka (Oryzias latipes) by rapid amplification of cDNA ends (RACE) technique. The full-length cDNA consists of 480 bp, and the open reading frame (CRF) of 189 bp encodes a polypeptide of 63 amino acids (aa) with a predicted molecular weight of 7.44 kDa. Its genomic organization was analyzed, and Southern blot detection confirmed that only one copy of beta-defensin exists in the medaka HNI strain. RT-PCR, Western blot and immunohistochemistry detections showed that the beta-defensin transcript and protein could be detected in eyes, liver, kidney, blood, spleen and gill, and obviously prevalent expression was found in eyes. Antimicrobial activity of the medaka beta-defensin was evaluated, and the antibacterial activity-specific to Gram-negative bacteria was revealed. Furthermore, the lipopolysaccharide (LPS), a major component of the outer membrane of Gram-negative bacteria, was demonstrated to be able to induce about 13-fol up-regulation of the beta-defensin within first 12 h. In addition, promoter and promoter mutagenesis analysis were performed in the medaka beta-defensin. A proximal 100 base pair(bp) sequence (+26 to -73)and the next 1700 bp sequence (-73 to -1755) were demonstrated to be responsible for the basal promoter activity and for the transcription regulation. Three nuclear factor kappa B (NF-kappa B) cis-elements and a Sp1 cis-element were revealed by mutagenesis analysis to exist in the 5' flanking sequence, and they were confirmed to be responsible for the up-regulation of medaka beta-defensin stimulated by LPS. And, the Sp1 cis-element was further revealed to be related to the basal promoter activity, and transcriptional factor II D (TFIID) was found to be in charge of the gene transcription initiation. All the obtained data suggested that the novel medaka beta-defensin should have antimicrobial activity-specific to Gram-negative bacteria, and the antibacterial immune function should be modulated by NF-kappa B and Sp1. (C) 2008 Elsevier Ltd. All rights reserved.

Direct measurement of the vortex migration caused by traveling magnetic wave

We studied the magnetisation of a 2 in. diameter YBCO thin film in the presence of traveling magnetic waves with six hall sensors. Simulation based on finite element method was conducted to reproduce the process of magnetisation. We discovered that the magnetisation of YBCO thin film based on traveling waves does not follow the constant current density assumption as used in the standing wave condition. We have shown that the traveling wave is more efficient in transporting the flux into the YBCO thin film, which suggests the potential of a flux injection device for high temperature superconducting coils. © 2014 AIP Publishing LLC.

Feasibility of 100G ethernet enabled by carrierless amplitude/phase modulation and optical OFDM

For the first time, simulations have analysed the feasibility of 100Gb/s CAP and OFDM systems over SMF links using 18.6GHz directly modulated lasers. We have shown that CAP-16/16-QAM-OFDM and CAP-64/64-QAM-OFDM over a single channel can successfully support transmission over 2km SMF, with power dissipation of ∼2 times that of a 4×25Gb/s NRZ system. © 2012 Optical Society of America.

FEC-free 50 m 1.5 Gb/s plastic optical fibre link using CAP modulation for home networks

LED-based carrierless amplitude and phase modulation is investigated for a multi-gigabit plastic optical fibre link. An FPGA-based 1.5 Gbit/s error free transmission over 50 m standard SI-POF using CAP64 is achieved, providing 2.9 dB power margin without forward error correction. © 2012 Optical Society of America.

Orthogonal multipulse modulation for next-generation datacommunication links

Orthogonal multipulse modulation is demonstrated to allow ≈30 Gb/s real-time transmission over multimode fibre using an 850 nm VCSEL. The scheme eases considerably component bandwidth requirements compared with conventional NRZ modulation. © 2011 OSA.

32 Gb/s multilevel modulation of an 850 nm VCSEL for next-generation datacommunication standards

An 850 nm vertical-cavity surface-emitting laser is modulated at 32 Gb/s using pulseamplitude modulation with four levels. Transmitter predistortion generates an optimized modulation waveform, which requires a receiver bandwidth of only 15 GHz. © OSA/ CLEO 2011.

40 Gb/s carrierless amplitude and phase modulation for low-cost optical datacommunication links

4 bps/Hz 40 Gb/s carrierless amplitude and phase (CAP) modulation is investigated for nextgeneration datacommunication links. The 40 Gb/s link achieves double the length of a conventional NRZ scheme, despite using a low-bandwidth source. © OSA/OFC/NFOEC 2011.

Carrierless amplitude and phase modulation for low-cost,high-spectral-efficiency optical datacommunication links

Carrierless amplitude and phase modulation for next-generation datacommunication links is considered for the first time. Low-cost implementation of a high-spectral-efficiency 10 Gb/s channel is demonstrated as a route to links at 40 Gb/s and beyond. © 2010 Optical Society of America.

Experimental demonstration of optical data links using a hybrid CAP/QAM modulation scheme.

The first known experimental demonstrations of a 10 Gb/s hybrid CAP-2/QAM-2 and a 20 Gb/s hybrid CAP-4/QAM-4 transmitter/receiver-based optical data link are performed. Successful transmission over 4.3 km of standard single-mode fiber (SMF) is achieved, with a link power penalty ∼0.4 dBo for CAP-2/QAM-2 and ∼1.5 dBo for CAP-4/QAM-4 at BER=10(-9).

All-optical amplitude-based broadband modulation in submicron silicon waveguide

We demonstrate an on-chip all-optical broadband modulation of light in submicron silicon waveguide based on linear free carriers' absorption using side coupling configuration of a pump signal. © 2010 Optical Society of America.

100 Gb/s PAM4-CAP2 real-time modulation of a single optical source for next-generation datacommunication links

100 Gb/s PAM4-CAP2 modulation is demonstrated for next-generation datacommunication links. Simulation studies indicate a power budget advantage of 2.5 dBo relative to PAM8 modulation. A real-time experimental demonstration is performed. © OSA 2014.

Local strain rate and curvature dependences of scalar dissipation rate transport in turbulent premixed flames: A direct numerical simulation analysis

The statistical behaviours of the instantaneous scalar dissipation rate Nc of reaction progress variable c in turbulent premixed flames have been analysed based on three-dimensional direct numerical simulation data of freely propagating statistically planar flame and V-flame configurations with different turbulent Reynolds number Ret. The statistical behaviours of N c and different terms of its transport equation for planar and V-flames are found to be qualitatively similar. The mean contribution of the density-variation term T1 is positive, whereas the molecular dissipation term (-D2) acts as a leading order sink. The mean contribution of the strain rate term T2 is predominantly negative for the cases considered here. The mean reaction rate contribution T3 is positive (negative) towards the unburned (burned) gas side of the flame, whereas the mean contribution of the diffusivity gradient term (D) assumes negative (positive) values towards the unburned (burned) gas side. The local statistical behaviours of Nc, T1, T2, T 3, (-D2), and f(D) have been analysed in terms of their marginal probability density functions (pdfs) and their joint pdfs with local tangential strain rate aT and curvature km. Detailed physical explanations have been provided for the observed behaviour. © 2014 Y. Gao et al.

APSK coded modulation schemes for nonlinear satellite channels with high power and spectral efficiency

A new class of 16-ary Amplitude Phase Shift Keying (APSK) coded modulations deemed double-ring PSK modulations best suited for (satellite) nonlinear channels is proposed. Constellation parameters optimization has been based on geometric and information-theoretic considerations. Furthermore, pre- and post-compensation techniques to reduce the nonlinearity impact have been examined. Digital timing clock and carrier phase have been derived and analyzed for a Turbo coded version of the same new modulation scheme. Finally, the performance of state-of the art Turbo coded modulation for this new 16-ary digital modulation has been investigated and compared to the known TCM schemes. It is shown that for the same coding scheme, double-ring APSK modulation outperforms classical 16-QAM and 16-PSK over a typical satellite nonlinear channel due to its intrinsic robustness against the High Power Amplifier (HPA) nonlinear characteristics. The new modulation is shown to be power- and spectrally-efficient, with interesting applications to satellite communications. © 2002 by the American Institute of Aeronautics and Astronautics, Inc.