Signal processing in high speed OTDM networks

This paper presents the design and experimental results of an optical packet-switching testbed capable of performing message routing with single wavelength TDM packet bit rates as high as 100 Gb/s

QKD in Standard Optical Telecommunications Networks

To perform Quantum Key Distribution, the mastering of the extremely weak signals carried by the quantum channel is required. Transporting these signals without disturbance is customarily done by isolating the quantum channel from any noise sources using a dedicated physical channel. However, to really profit from this technology, a full integration with conventional network technologies would be highly desirable. Trying to use single photon signals with others that carry an average power many orders of magnitude bigger while sharing as much infrastructure with a conventional network as possible brings obvious problems. The purpose of the present paper is to report our efforts in researching the limits of the integration of QKD in modern optical networks scenarios. We have built a full metropolitan area network testbed comprising a backbone and an access network. The emphasis is put in using as much as possible the same industrial grade technology that is actually used in already installed networks, in order to understand the throughput, limits and cost of deploying QKD in a real network

Selenoprotein P Influences Colitis-Induced Tumorigenesis by Mediating Stemness and Oxidative Damage.

Patients with inflammatory bowel disease are at increased risk for colon cancer due to augmented oxidative stress. These patients also have compromised antioxidant defenses as the result of nutritional deficiencies. The micronutrient selenium is essential for selenoprotein production and is transported from the liver to target tissues via selenoprotein P (SEPP1). Target tissues also produce SEPP1, which is thought to possess an endogenous antioxidant function. Here, we have shown that mice with Sepp1 haploinsufficiency or mutations that disrupt either the selenium transport or the enzymatic domain of SEPP1 exhibit increased colitis-associated carcinogenesis as the result of increased genomic instability and promotion of a protumorigenic microenvironment. Reduced SEPP1 function markedly increased M2-polarized macrophages, indicating a role for SEPP1 in macrophage polarization and immune function. Furthermore, compared with partial loss, complete loss of SEPP1 substantially reduced tumor burden, in part due to increased apoptosis. Using intestinal organoid cultures, we found that, compared with those from WT animals, Sepp1-null cultures display increased stem cell characteristics that are coupled with increased ROS production, DNA damage, proliferation, decreased cell survival, and modulation of WNT signaling in response to H2O2-mediated oxidative stress. Together, these data demonstrate that SEPP1 influences inflammatory tumorigenesis by affecting genomic stability, the inflammatory microenvironment, and epithelial stem cell functions

Rule-Based Cell Systems Model of Aging using Feedback Loop Motifs Mediated by Stress Responses

Investigating the complex systems dynamics of the aging process requires integration of a broad range of cellular processes describing damage and functional decline co-existing with adaptive and protective regulatory mechanisms. We evolve an integrated generic cell network to represent the connectivity of key cellular mechanisms structured into positive and negative feedback loop motifs centrally important for aging. The conceptual network is casted into a fuzzy-logic, hybrid-intelligent framework based on interaction rules assembled from a priori knowledge. Based upon a classical homeostatic representation of cellular energy metabolism, we first demonstrate how positive-feedback loops accelerate damage and decline consistent with a vicious cycle. This model is iteratively extended towards an adaptive response model by incorporating protective negative-feedback loop circuits. Time-lapse simulations of the adaptive response model uncover how transcriptional and translational changes, mediated by stress sensors NF-κB and mTOR, counteract accumulating damage and dysfunction by modulating mitochondrial respiration, metabolic fluxes, biosynthesis, and autophagy, crucial for cellular survival. The model allows consideration of lifespan optimization scenarios with respect to fitness criteria using a sensitivity analysis. Our work establishes a novel extendable and scalable computational approach capable to connect tractable molecular mechanisms with cellular network dynamics underlying the emerging aging phenotype

Highly scalable optical TDM router using a computer controlled time slot selector with picosecond resolution

An OTDM router architecture using a highly scalable time slot tuner is discussed. Results for a 100-Gb/s, 16-channel router using a computer-controlled interface are presented. The scalability and latency of the router based upon the time slot tuner shows that aggregate bandwidths beyond 1 Tb/s are possible. We show that a maximum hardware time slot access latency of less than 3.2 ns can be achieved with this architecture enabling ultrafast optical packet routing

TDM 100Gbit/s packet switching in an optical shufflenet

In this paper we present an OTDM multihop prototype network developed in the Lightwave Communication Laboratory at Princeton University. Employing a new self-routing scheme with special address coding suitable for optical packet switching, we demonstrate 100 Gbit/s optical packet switching in an 8-node transparent shufflenetwork which offers extremely high bandwidth and low latency. Our design has also made the network highly scalable, the results from the performance studies of this network can be extended to many other multihop network topologies of larger sizes

All-optical clock and data separation technique for asynchronous packet-switched optical time-division-multiplexed networks

We propose and experimentally demonstrate an all-optical technique for separating a clock synchronization pulse from an optical time-division-multiplexed (OTDM) 100 Gb/s data packet. The technique is based on an all-optical switching device combined with optical feedback. This approach removes limitations found in other techniques such as those that are sensitive to long strings of zeroes in the data packet

Fully-Programmable Ring Resonator Based Integrated Photonic Circuit For Phase Coherent Applications

We demonstrate a novel reconfigurable ring resonator based integrated photonic chip with ultra-fine frequency resolution for spectral phase encoding. A spectrally efficient four-user OCDMA system is shown to operate at 2.5 Gb/s with BER\u3c 10-9. © 2005 Optical Society of America

Demonstration of 16-channel multiple-access analog optical TDM with 10 ps channel spacing

Many high-bandwidth analog communication systems require the processing of a large number of analog signals such as CATV distribution networks and antenna routing subsystems. Fiber optics technology has the capability to meet the requirements of these applications. Thus far, the vast majority of research on fiber-optic analog communications has concentrated on the modulation of continuous wave (CW) lasers for encoding data, such as sub-carrier multiplexing (SCM). However, since the signals are multiplexed and demultiplexed in the electrical domain, the maximum number of channels is limited in such a system due to intermodulation distortion caused by nonlinearities in the electrical-optical-electrical conversion process. In contrast, the techniques presented in the work are based on the multiplexing and demultiplexing of signals in the optical domain, thereby reducing nonlinear interactions between channels. In our approach, each analog signal is encoded as an envelope onto an optical pulse train. By using ultrashort optical pulses to sample the analog waveforms, multiple channels can be interleaved and combined resulting in TDMA frames of pulsed analog data. The individual channels can then be extracted from the aggregate pulse stream with the use of an ultrafast optical gating device, such as the terahertz optical asymmetric demultiplexer