Evolution to 200G Passive Optical Network

New generation passive optical network aims at providing more than 100 Gb/s capacity. Thanks to recent progress enabling a variety of optical transceivers up to 40 Gb/s, many evolution possibilities to 200G PONs (passive optical network) could be investigated. This work proposes two directly deployable cases of evolution to 200G PON based on the combination of these improved optical transceivers and WDM (wavelength division multiplexing). The physical layer of the optical network has been simulated with OptiSystem software to show the communication links performances behavior when considering key components parameters in order to achieve good network design for a given area. The complexity of the proposed architectures and financial cost comparisons are also discussed.Comment: http://www.davidpublishing.com/davidpublishing/Upfile/2/7/2013/2013020707494407.pd

Analysis and experiments on C band 200G coherent PON based on Alamouti polarization-insensitive receivers

Passive optical network (PON) based on coherent detection has attracted a great deal of attention in recent years as a future solution for 100+ Gbps per wavelength. Particularly for 200G-PON, one of the most attractive options would be to switch to QAM transmission and coherent detection, due to its well know advantages compared to the Direct-Detection approaches used so far in PON. However, coherent technology, extensively used in core networks, has costs that are still perceived as too high for the access ecosystem. In order to perform cost reduction, some groups have studied the option of coherent polarization-independent (PI) detection, since it halves the number of optoelectronic components in the receiver front end. In this paper, we thus present a detailed simulative and experimental investigation of polarization-independent receivers to achieve 200 Gbps transmission in C band using the Alamouti polarization time block coding (PTBC). Our goal is to show what would be the system requirements in terms of optoelectronic bandwidths, laser phase noise and ultimate power budget limitations. We study two different modulation formats: quadrature phase-shift keying (QPSK) and 16 quadrature amplitude modulation (16QAM). We also compare heterodyne and homodyne/intradyne solutions through simulations. As a summarizing result, we experimentally show that 200G PON based on 50 Gbaud-16QAM single-polarization Alamouti coded signals would be possible with today state-of-the-art coherent technologies, demonstrating an Optical Distribution Network loss above 33 dB with 25 km fiber length, a very promising result that is compliant with the PON power budget E1 class

Overview of high-speed TDM-PON beyond 50 Gbps per wavelength using digital signal processing [Invited Tutorial]

The recent evolution of passive optical network standards and related research activities for physical layer solutions that achieve bit rates well above 10 Gbps per wavelength (lambda) is discussed. We show that the advancement toward 50, 100, and 200 Gbps/lambda will certainly require a strong introduction of advanced digital signal processing (DSP) technologies for linear, and maybe nonlinear, equalization and for forward error correction. We start by reviewing in detail the current standardization activities in the International Telecommunication Union and the Institute of Electrical and Electronics Engineers, and then we present a comparison of the DSP approaches for traditional direct detection solutions and for future coherent detection approaches. (c) 2022 Optica Publishing Grou

Silicon circuits for chip-to-chip communications in multi-socket server board interconnects

Multi-socket server boards (MSBs) exploit the interconnection of multiple processor chips towards forming powerful cache coherent systems, with the interconnect technology comprising a key element in boosting processing performance. Here, we present an overview of the current electrical interconnects for MSBs, outlining the main challenges currently faced. We propose the use of silicon photonics (SiPho) towards advancing interconnect throughput, socket connectivity and energy efficiency in MSB layouts, enabling a flat-topology wavelength division multiplexing (WDM)-based point-to-point (p2p) optical MSB interconnect scheme. We demonstrate WDM SiPho transceivers (TxRxs) co-assembled with their electronic circuits for up to 50 Gb/s line rate and 400 Gb/s aggregate data transmission and SiPho arrayed waveguide grating routers that can offer collision-less time of flight connectivity for up to 16 nodes. The capacity can scale to 2.8 Gb/s for an eight-socket MSB, when line rate scales to 50 Gb/s, yielding up to 69% energy reduction compared with the QuickPath Interconnect and highlighting the feasibility of single-hop p2p interconnects in MSB systems with >4 sockets

Pulse-Shape Analysis of PDM-QPSK Modulation Formats for 100 and 200 Gb/s DWDM transmissions

Advanced optical modulation format polarization-division multiplexed quadrature phase shift keying (PDM-QPSK) has become a key ingredient in the design of 100 and 200-Gb/s dense wavelength-division multiplexed (DWDM) networks. The performance of this format varies according to the shape of the pulses employed by the optical carrier: non-return to zero (NRZ), return to zero (RZ) or carrier-suppressed return to zero (CSRZ). In this paper we analyze the tolerance of PDM-QPSK to linear and nonlinear optical impairments: amplified spontaneous emission (ASE) noise, crosstalk, distortion by optical filtering, chromatic dispersion (CD), polarization mode dispersion (PMD) and fiber Kerr nonlinearities. RZ formats with a low duty cycle value reduce pulse-to-pulse interaction obtaining a higher tolerance to CD, PMD and intrachannel nonlinearities

Physical Layer Aware Optical Networks

This thesis describes novel contributions in the field of physical layer aware optical networks. IP traffic increase and revenue compression in the Telecom industry is putting a lot of pressure on the optical community to develop novel solutions that must both increase total capacity while being cost effective. This requirement is pushing operators towards network disaggregation, where optical network infrastructure is built by mix and match different physical layer technologies from different vendors. In such a novel context, every equipment and transmission technique at the physical layer impacts the overall network behavior. Hence, methods giving quantitative evaluations of individual merit of physical layer equipment at network level are a firm request during network design phases as well as during network lifetime. Therefore, physical layer awareness in network design and operation is fundamental to fairly assess the potentialities, and exploit the capabilities of different technologies. From this perspective, propagation impairments modeling is essential. In this work propagation impairments in transparent optical networks are summarized, with a special focus on nonlinear effects. The Gaussian Noise model is reviewed, then extended for wideband scenarios. To do so, the impact of polarization mode dispersion on nonlinear interference (NLI) generation is assessed for the first time through simulation, showing its negligible impact on NLI generation. Thanks to this result, the Gaussian Noise model is generalized to assess the impact of space and frequency amplitude variations along the fiber, mainly due to stimulated Raman scattering, on NLI generation. The proposed Generalized GN (GGN) model is experimentally validated on a setup with commercial linecards, compared with other modeling options, and an example of application is shown. Then, network-level power optimization strategies are discussed, and the Locally Optimization Global Optimization (LOGO) approach reviewed. After that, a novel framework of analysis for optical networks that leverages detailed propagation impairment modeling called the Statistical Network Assessment Process (SNAP) is presented. SNAP is motivated by the need of having a general framework to assess the impact of different physical layer technologies on network performance, without relying on rigid optimization approaches, that are not well-suited for technology comparison. Several examples of applications of SNAP are given, including comparisons of transceivers, amplifiers and node technologies. SNAP is also used to highlight topological bottlenecks in progressively loaded network scenarios and to derive possible solutions for them. The final work presented in this thesis is related to the implementation of a vendor agnostic quality of transmission estimator for multi-vendor optical networks developed in the context of the Physical Simulation Environment group of the Telecom Infra Project. The implementation of a module based on the GN model is briefly described, then results of a multi-vendor experimental validation performed in collaboration with Microsoft are shown

Coherent diffusive photon gun for generating nonclassical states

Funding: EU Flagship on Quantum Technologies, project PhoG (820365). D.M., A.S., and A.M. also acknowledge support from the National Academy of Sciences of Belarus program “Convergence,” and the BRRFI project F18U-006.We suggest and discuss a concept of a deterministic integrated source of nonclassical light based on the coherent diffusive photonics, a coherent light flow in a system of dissipatively coupled waveguides. We show how this practical quantum device can be realized with a system of single-mode waveguides laser inscribed in nonlinear glass. We describe a hierarchy of models, from the complete multimode model of the waveguide network to the single mode coupled to a bath, analyze the conditions for validity of the simplest single-mode model and demonstrate feasibility of the generation of bright sub-Poissonian light states merely from a coherent input. Notably, the generation of nonclassical states occurs at the initial stages of the dynamics, and can be accounted for in the linear model that allows us to circumvent the prohibiting computational complexity of the exact full quantum representation.Publisher PDFPeer reviewe

Experimental Demonstration of Soft-ROADMs with Dual-Arm Drop Elements for Future Optical-Wireless Converged Access Networks

Digital signal processing (DSP)-enabled soft reconfigurable optical add/drop multiplexers (Soft-ROADMs) offer flexible add/drop optical switching at wavelength, sub-wavelength and spectrally-overlapped orthogonal (I and Q) sub-band (SB) levels, which makes them highly desirable for enabling flexible reconfigurable optical-wireless converged access networks where both fixed and wireless access services are consolidated in a shared network, enabling network resource efficient and cost-effective connectivity solutions. However, the performance of the targeted sub-band (TSB) extracted by the soft-ROADM drop element is extremely sensitive to drop RF signal phase offset, which is a major limitation impacting the technical feasibility of soft-ROADMs. To overcome this challenge, in this paper, a phase-offset-insensitive soft-ROADM dual-arm IQ drop operation is proposed and experimentally demonstrated. A DSP implemented multi-input multi-output (MIMO)-based I/Q crosstalk mitigation technique is employed to achieve the insensitivity to drop RF signal phase offset. It is shown that, the traditional single-arm I/Q soft-ROADM drop element has a limited drop RF signal phase offset dynamic range of ~±/

Kirigami inspired shape programmable and reconfigurable multifunctional nanocomposites for 3D structures

The ability to shape and program remotely and contactlessly from two-dimensional (2D) flat multilayer materials into three-dimensional (3D) structures and functional devices could be ideal for applications like space missions, environmental remediation and minimally invasive surgery. However, achieving a fast and accurate deployment of complex 3D shapes contaclessly at low energy consumption, while embedding a number of physical properties and functionalities, remains very challenging. Herein, a strategy to widen the complexity space of 3D shapes and functions achievable is demonstrated, by enabling a controlled sequential folding while incorporating nano-reinforcements. Sequential folding was successfully achieved and a honeycomb structure was developed by designing multilayer polymer films with different kirigami patterns - each responding at a different rate upon heating. A finite element method (FEM) model was developed to better understand the main underlying physical mechanism as well as to feedback into materials and structure design. Moreover, a shape-programmed CNT veil-based honeycomb structure was developed, triggered remotely by thermal stimuli, with capability to self-sense the folding state through the electrical resistance change (ΔR/R0 = 100–300 %). Overall, it was demonstrated that designing layered nanocomposites with different 2D patterns allows an accurate sequential folding into 3D structures, with bespoke physical properties and integrated sensing–actuating functionalities