Redundancy Strategies for a High Splitting Optically Amplified Passive Optical Network

Copyright IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE.High splitting, optically amplified, passive optical networks (SuperPONs) are investigated in terms of redundancy provision and protection mechanisms. Options for redundancy, including the important special case of dual homing, are detailed, and it is determined as to which of these options (duplication of the feeder and first distribution section, and N+1 protection of the optical amplifiers in the amplified splitter) would be required to be provided to all attached users to facilitate appropriate availability of the basic telephony service. The distributed amplified splitter dual homing solution is found to outperform the single amplified splitter solution in terms of its survivability. The protection mechanisms necessary to automatically switch to the redundant provision are discussed and it is seen that with the aid of suitable regular precautionary procedures protection switching can generally be provided rapidly (<50 ms). Finally, an availability, and cost versus availability, study confirms the aforementioned redundancy assessment for fiber-to-the-home (FTTH) implementations, but shows fiber-to-the-curb (FTTC) as needing additional redundancyPeer reviewe

200 Gbps/λ PON Downstream C-Band Direct-Detection Links with ≥29 dB Power Budget

In this paper we present the simulative analysis of a 200 Gbps per wavelength (λ) 8-level pulse amplitude modulation (PAM-8) downstream communication over up to 20 km single mode fiber (SMF) in C-band based on direct detection (DD) achieving at least a 29 dB link power budget in a PON environment. We use chromatic dispersion digital pre-compensation (CD-DPC) and a dual-arm in-phase and quadrature Mach–Zehnder modulator (IQ-MZM) at the optical line termination (OLT) side, while preserving DD in the optical network unit (ONU). Three receiver digital-signal-processing (DSP) options are analyzed and compared: square-root-like technique (SQRT) in combination with a feed forward equalizer (FFE) and a decision feedback equalizer (DFE), the Volterra nonlinear equalizer (VNLE), and the SQRT in combination with the VNLE. The SQRT can be applied in combination with the VNLE to decrease the receiver DSP complexity while maintaining the required system performance. We show that PAM-8 with CD-DPC and the SQRT in combination with the VNLE is a feasible solution for 200 Gbps per λ downstream C-band transmission for PON

Opportunities and challenges when using low bandwidth optics for higher capacity PON systems

Next generation PON physical layer, targeting 50 Gbit/s/lambda, has to deal with optoelectronics bandwidth limitation. In this invited paper, we review the resulting required bandwidths and discuss the trade-off between receivers with or without equalization

Field demonstration of 25G-PON and XGS-PON burst-mode upstream coexistence

We perform a field demonstration of 25 Gb/s burst-mode upstream duobinary transmission in O-band using 10G optoelectronics and APD-based optical receiver with memory-aided adaptive equalization, coexisting with XGS-PON transmission. We achieve 31 dB ODN loss budget and show marginal interference penalty between the two systems

CYP17A1 polymorphism c.-362T>C predicts clinical outcome in metastatic castration-resistance prostate cancer patients treated with abiraterone

Background: Abiraterone became&nbsp;a standard hormonal therapy for patients with metastatic castration-resistance prostate cancer (mCRPC). However, patients may experience primary resistance to treatment. To date, few predictive biomarkers of efficacy have been identified. Our aim was to investigate the association between the&nbsp;single nucleotide polymorphism (SNP) c.-362T&gt;C&nbsp;in the&nbsp;CYP17A1 gene, and clinical outcome in mCRPC patients treated with abiraterone. Patients and methods: mCRPC patients candidate to receive abiraterone were enrolled in the present retrospective pharmacogenetic study. Based on a literature selection, CYP17A1 rs2486758 (c.-362T &gt; C) was selected and analysed by real-time PCR on genomic DNA extracted from whole blood. Univariate analysis was performed to test the association between the&nbsp;SNP and treatment-related clinical outcomes. Results: Sixty mCRPC patients were enrolled in the present study. Patients carrying the mutant CYP17A1 c.-362CT/CC genotypes showed a shorter median progression-free survival (PFS) and prostate-specific antigen-PFS (PSA-PFS) compared to patients carrying the TT genotype (10.7 vs 14.2&nbsp;months and 8 vs 16&nbsp;months, respectively;&nbsp;p = 0.04). No association between the selected SNP and the overall survival was found. Conclusions: These findings suggest an association between CYP17A1 c.-362T&gt;C&nbsp;polymorphism and poorer clinical outcome with abiraterone for mCRPC patients. However, further validations on larger cohort of patients are needed to confirm its role as a predictive biomarker for abiraterone resistance

Experimental Demonstration of DSP-Assisted Electrical Duobinary Optimization for High Speed PON 25+ Gbps Using 10 Gbps APD Receiver

We compare experimentally two variants of electrical duobinary using adaptive equalization for 25-40Gbps high-speed PON, showing the advantageous of designing an automatic digital signal processing receiver selecting the more appropriate adaptive equalization depending on available bandwidth and link dispersio

Feasibility of next-generation 25 Gbps PON using non-return to zero modulation

In this paper, two different receiver schemes based on non-return to zero (NRZ) modulation format to implement next generation 25 Gbps passive optical network (PON) links are compared in terms of performance. One scheme is based on the re-use of 10 Gbps PON optoelectronic components adding a DSP-based adaptive equalizer at the receiver. The other avoids the use of equalization but requires higher-bandwidth components (i.e. 25 Gbps technology developed for data centre interconnects). By means of simulations, we demonstrate that both schemes can operate through 20-km of single mode fibre in O-band achieving similar performance and power requirements

Towards 50 Gb/s in High-Speed PON: Optimization of Modulation Formats Using Pre-Chirping

High-Speed (HS) Passive Optical Network (PON) alternatives with single-wavelength capacity higher than 10 Gb/s, such as 25 and 50 Gb/s, are currently under investigation, development and standardization. Modulation formats based on intensity modulation and direct detection (IM-DD) have been preferred to implement next generation HS-PON due to their advantages in terms of complexity and cost. Among them, conventional Binary Pulse Amplitude Modulation (PAM-2) format, as well as Quaternary PAM (PAM-4) and Electrical Duo-Binary (EDB), have been emerged as the most widely employed. In previous works, we have shown that any of these formats is feasible for the transmission of 50 Gb/s using currently available 25 Gb/s technology when operating in C-band of single mode fibre (SMF) for typical PON distances (i.e., 20 km). In this contribution, we introduce the use of pre-chirping technique in order to overcome this reach limitation. We compare the achievable performance of PAM-2, PAM-4 and EDB under demanding bandlimited and dispersive conditions on the transmission of 50 Gb/s using adaptive equalization, with and without pre-chirping. By means of simulations, we demonstrate that using pre-chirping enables the operation of PAM-2 and PAM-4 on the transmission of 50 Gb/s through 20-km of SMF in O- and C-band, respectively, using currently available technology

Burst-Mode Equalization Strategies in 25 Gbps US-PON using Duobinary and 10G-Class APD for 20-km in C-Band

25 Gbps burst-mode upstream duobinary transmission in C-band using 10G optoelectronics and APD-based adaptive equalization receiver is analyzed and experimentally demonstrated. We show a memory-aided alternative that avoids the long training preambles (>2600 bits) needed in commonly proposed memoryless approaches

Il telelavoro per i disabili, opportunit e barriere (l'esperienza del progetto europei T1003 TWIN)

pag 607-618Consiglio Nazionale delle Ricerche (CNR). Biblioteca Centrale / CNR - Consiglio Nazionale delle RichercheSIGLEITItal