The next-generation passive optical network stage 2 (NG-PON2) effort was initiated by the full service access network (FSAN) in 2011 to investigate on upcoming technologies enabling a bandwidth ...increase beyond 10 Gb/s in the optical access network. The FSAN meeting in April 2012 selected the time- and wavelength-division multiplexed passive optical network (TWDM-PON) as a primary solution to NG-PON2. In this paper, we summarize the TWDM-PON research in FSAN by reviewing the basics of TWDM-PON and presenting the world's first full-system 40 Gb/s TWDM-PON prototype. After introducing the TWDM-PON architecture, we explore TWDM-PON wavelength plan options to meet the NG-PON2 requirements. TWDM-PON key technologies and their respective level of development are further discussed to investigate its feasibility and availability. The first full-system 40 Gb/s TWDM-PON prototype is demonstrated to provide 40 Gb/s downstream and 10 Gb/s upstream bandwidth. This full prototype system offers 38 dB power budget and supports 20 km distance with a 1:512 split ratio. It coexists with commercially deployed Gigabit PON (G-PON) and 10 Gigabit PON (XG-PON) systems. The operator-vendor joint test results testify that TWDM-PON is achievable by the reuse and integration of commercial devices and components.
We experimentally demonstrate 200 Gb/s/<inline-formula> <tex-math notation="LaTeX">\lambda </tex-math></inline-formula> upstream coherent passive optical network (PON) using polarization division ...multiplexed (PDM) pulse amplitude modulation 4-level (PAM4) signal with coherent detection. The 50 GBaud PDM-PAM4 is generated using a low cost C-band electro-absorption modulated laser (EML), polarization-division multiplexing (PDM) emulator and semiconductor optical amplifier (SOA). A power budget of 29.4 dB is achieved for 25 km single mode fiber (SMF) transmission using a class-40 integrated coherent receiver (ICR) at the optical line terminal (OLT).
In this letter, a bidirectional symmetric 100 Gb/s/<inline-formula> <tex-math notation="LaTeX">\lambda </tex-math></inline-formula> coherent passive optical network (PON) scheme with a simplified ...optical network unit (ONU) transceiver is proposed and experimentally demonstrated. In the proposed scheme, the downstream signal is generated in a dual-polarization coherent transmitter with Alamouti-coding at the optical line terminal (OLT) side and then received by a single-polarization heterodyne receiver at the ONU side. The upstream signal is generated in a low-cost C-band electro-absorption modulated laser (EML) at the ONU side and then received by a standard dual-polarization integrated coherent receiver at the OLT side. The experimental results show that more than 30 dB power budget is achieved after 25 km standard single mode fibre transmission for both downstream and upstream signal at 100 Gb/s/<inline-formula> <tex-math notation="LaTeX">\lambda </tex-math></inline-formula>. The cost at the ONU side is maintained low as the required bandwidth of the optoelectrical device is >25 GHz and the local oscillator power at the ONU side can be as low as 4 dBm.
We experimentally demonstrate 200 Gb/s/<inline-formula> <tex-math notation="LaTeX">\lambda </tex-math></inline-formula> downstream transmission for a passive optical network (PON) with a minimal ...coherent receiver at optical network unit (ONU). The low complexity receiver required at the cost-sensitive ONU employs heterodyne detection and requires a single photodiode, a 3-dB optical coupler and a local oscillator, and is the simplest coherent receiver. At the optical line terminal (OLT), digital pre-emphasis and Alamouti-coding is applied to the 50 GBaud signal. A power budget of 29 dB is experimentally demonstrated, increasing to 34.5 dB if a balanced receiver is utilized.
This paper presents the world's first field trial of a 40-km reach and over 512-split symmetric-rate 40-Gbit/s λ-tunable time and wavelength division multiplexing passive optical network (TWDM-PON) ...that utilizes our newly developed high-speed λ-tunable optical network unit transceivers and automatic gain controlled semiconductor optical amplifier-based PON extender for repeater and central office use. The upstream signals for C-band and downstream signals for L+-band in our developed λ-tunable TWDM-PON comply with the wavelength plan of ITU-T G.989 series. In a field trial, we successfully demonstrate error free λ-tunable transmission for the 40-km reach and 1024-split (maximum number) symmetric-rate 40-Gbit/s λ-tunable TWDM-PON over installed standard single-mode fiber links, and advanced network functions such as dynamic load balancing, incremental system upgrade, optical subscriber unit protection, and OLT equipment power saving are also confirmed.
In this paper, we propose a key space enhanced chaos-based encryption scheme with no requirement of redundant sideband information in an orthogonal frequency division multiplexing passive optical ...network (OFDM-PON). For the first time, a simple 1-D chaotic logistic map is employed to scramble the chaotic subcarrier allocation both in time/frequency domain and logical operation, which provides a huge key space to enhance the physical layer confidentiality. Due to the dynamic chaotic permutations, the largest key space is achieved in comparison with the reported encryption schemes in OFDM-PON. In addition, a ~10-Gb/s secure transmission with encrypted OFDM data is experimentally demonstrated over 25-km standard single-mode fiber. The proposed encryption scheme demonstrates the excellent security of data transmission in OFDM-PON and the robustness against exhaustive attacks.
We demonstrate concepts and results of a field trial for a flexible-rate passive optical network (FLCS-PON), which delivers bitrates up to 100 Gbit/s and allows for adaptations in the transmission ...method to match the users' channel conditions and optimize throughput. FLCS-PON builds on top of the hardware ecosystem that will be developed for ITU-T 50 Gbit/s PON and employs three new ingredients: optical network unit (ONU) grouping, flexible modulation format, and flexible forward error correction (FEC) code rate. Together, these techniques take advantage of the optical distribution network (ODN) statistics to realize a system capable of more than twofold throughput increase compared to the upcoming 50 Gbit/s PON, but still able to support a full array of deployed fiber edge cases, which are problematic for legacy PONs. In this paper we explain the concepts behind enabling techniques of FLCS-PON. We then report on a field trial over a deployed fiber infrastructure, using a system consisting of one FLCS-PON OLT and two ONUs. We report both pre- and post-forward-error-correction (post-FEC) performance of our system, demonstrating achievable net bitrate over an operator's fiber infrastructure. We realize a downlink transmission at double the speed of ITU-T 50 Gbit/s PON for ONUs exhibiting lower optical path loss (OPL), while simultaneously continue to support ONUs at high OPLs. We additionally realize a record-high 31.5 dB loss budget for 100 Gbit/s transmission using a direct-detection ONU with an optical preamplifier.
In this paper, we present the first 100-Gb/s/λ-based coherent wavelength division multiplexing passive optical network (WDM-PON) prototype system, highlighting a real-time 100-Gb/s coherent ...transceiver with a simplified digital signal processing suitable for access spans, and a new automatic-gain-controlled erbium-doped fiber amplifier based preamplifier with an amplified spontaneous emission compensation function for the upstream to improve the minimum receiver sensitivity for coherent detection, especially at very low received signal power. Thanks to our proposed technologies, this first demonstration achieved an increased bidirectional loss budget of more than 39.1 dB, which supports 80 km transmission with eight optical network unit splits, with an improved upstream receiver sensitivity of -38.1 dBm. In addition, to show the feasibility of the proposed 100-Gb/s/ λ-based coherent WDM-PON as a promising candidate for forthcoming 5G mobile fronthaul networks, we further investigate experimentally a 128-kb/s auxiliary management and control channel (AMCC) superimposed on the 100-Gb/s dual polarization quadrature phase-shift keying (DP-QPSK) signals employed by the 100-Gb/s/λ -based coherent WDM-PON system. By setting the modulation index of the AMCC signals between 5% and 40%, we also successfully demonstrated 100-Gb/s DP-QPSK signal transmission with only a small power penalty of 0.2 dB due to the introduction of the AMCC signal.
Passive optical networks (PON) have become a promising solution for accessing networks because of the advantages they offer, such as high efficiency, security, and cost reduction. However, network ...management in PON is not yet automated and needs network operator intervention. In recent years, software-defined networking (SDN) has become an emerging technology. Through the separation of control and data plane in SDN switches, SDN provides dynamically fine-grained traffic control that enhances total network controllability and manageability. In this paper, we leverage the benefits of gigabit-capable passive optical network (GPON), while enhancing its capabilities on traffic management to the same level as an SDN switch. More specifically, we abstract the underlying physical GPON into an OpenFlow-enabled virtual SDN switch. The virtual switch can be used to connect multiple sites in widespread geographic locations. Similar to a real OpenFlow switch, a GPON virtual switch can be controlled by a standard OpenFlow controller. In our design, an embedded OpenFlow agent resides in the optical line termination (OLT) of the underlying GPON. The agent communicates with the external OpenFlow controller and simultaneously uses optical network unit management and control interface inside the OLT to manage ONUs. We created a prototype system based on a commodity GPON network. In the virtual switch, we implemented all the OpenFlow functions, including packet forwarding, bandwidth metering, statistical data collection, and status reporting. The experimental results show that the GPON virtual switch can correctly perform all the functions defined in the OpenFlow 1.3 specification. Its performance on flow entry modification time, dynamic bandwidth control, and switch status monitoring are comparable to the performance of a real OpenFlow switch.
The Passive Optical Network (PON) has been evolving continuously in terms of architecture and capacity to keep up with the demand for high-speed Internet access in the access network segment. ...Recently, integration of Software-Defined Networking (SDN), which provides programmable and (logically) centralized network control, with PON has attracted intensive research interest to further enhance PON performance and reduce operational and capital expenditure. Although PON is regarded as an energy-efficient access network solution, it would be a major contributor for increasing energy consumption in the access network segment because of its higher penetration rate than other access network technologies. Over the past several years, the major standardization bodies like IEEE and ITU-T, and research communities have engaged in introducing energy-efficient PON solutions. This article familiarizes readers with PON evolution in terms of capacity, architecture, and its integration with virtualization and SDN based control. We present a comprehensive survey of the energy conservation research efforts in PON starting from conventional PON to SDN based PON leveraging virtual and physical network functions. This article also presents contemporary energy-efficient standardization activities in IEEE and ITU-T. To the best of our knowledge, to date, this article is the first most comprehensive survey on energy saving research and standardization on PON. We summarize the lessons learned from the recent advancements, identify important challenges ahead and outline several future research directions that can contribute to further advancement of energy-efficient PON.
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