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(a) Photo of color-coded OLT optics; (b) Sensitivity of OLT receiver with and without pre-amplification. ROP-Received Optical Power.
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We present a long-reach wavelength-routed time-wavelength division multiplexing (TWDM) passive optical network (PON) architecture (LRWR-PON) and its commercial implementation, that supports up to 768 users per fiber strand and up to 50-km transmission distance. The increased reach allows central offices to become more flexible and fewer in quantity...
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Sinc-shaped Nyquist pulses have a rectangular spectrum. In the spectral domain, adjacent Nyquist wavelength division multiplexed (WDM) channels can be multiplexed without any guard band. Theoretically, they can be used to transmit the maximum possible symbol and data rate. The demultiplexing of channels requires filters with transfer functions that...
Citations
... LRPONs utilize advanced components, such as optical amplifiers, and multiplexing technologies, such as wavelength-division multiplexing (WDM), to extend the reach of traditional PONs beyond their typical distance limit of 20 km [7,8]. These technologies allow LRPONs to cover larger geographical areas with higher data rates and lower loss rates, providing a cost-effective solution for meeting the increasing demand for high-speed Internet access and new online services. ...
... These technologies allow LRPONs to cover larger geographical areas with higher data rates and lower loss rates, providing a cost-effective solution for meeting the increasing demand for high-speed Internet access and new online services. The expansion of the coverage area for LRPONs requires not only longer distances, but also the ability to support a larger number of users and a higher capacity for aggregating traffic [7]. LRPONs also offer the added benefit of simplifying the network by reducing the number of equipment interfaces, network elements, and nodes, and by allowing the consolidation of major central offices [9,10]. ...
... This method is increasingly being used in the deployment of new LRPON systems to increase the capacity and bandwidth of PON systems. The TWDM-based LRPON system is based on a hybrid technique that combines the capacity-enhancing benefits of wavelength division multiplexing with the resource granularity of time division multiplexing [7]. This allows for an increase in the upstream channel capacity by using multiple wavelengths, typically four or eight, to achieve a maximum capacity of 40 Gbps or 80 Gbps, meeting the requirements of the NG-PON2 standards [2]. ...
In recent years, there has been an increasing trend towards extending the coverage of passive optical networks (PONs) over large geographical areas. Long-reach PONs (LRPONs) are capable of extending the distance covered by PONs from 20 km to 100 km, leading to cost savings in the network operation by reducing the number of central offices. They have become widely deployed due to their ability to provide high-speed, long-distance data transmission over optical fibers. In addition, the next generation of optical access networks are expected to provide high-capacity mobile and wireless backhauling over a wide coverage area. However, this extended reach also requires the design of efficient dynamic bandwidth allocation (DBA) schemes to address the performance degradation caused by the increased propagation delay in LRPONs. The DBA schemes commonly used for upstream traffic transmission in traditional PONs are not well-suited for use in LRPONs due to their inefficiency in bandwidth utilization due to the increased round-trip time (RTT) between the optical line terminal (OLT) and the optical network unit (ONU). In this study, we present an efficient DBA algorithm, the Distance-Weighted Bandwidth Allocation DWDBA Algorithm, specifically enhanced for multi-wavelength LRPONs. Our DBA algorithm utilizes a scheduling policy that assigns weight vectors to Optical Network Units (ONUs) based on their distance from the Optical Line Terminal (OLT), sorting them accordingly without penalizing any ONU due to their distance. The DWDBA takes the laser tuning time into consideration. We conducted extensive simulations to evaluate the performance of the proposed algorithm under various scenarios and compared it to the IPACT algorithm. The results of the simulations show that the proposed algorithm outperformed the IPACT algorithm in terms of bandwidth utilization and queue delay.
... In this paper, we experimentally show successful C-band operation over 25.23 km, 50.46 km, 81.1 km and 106.2 km of standard SMF, achieving more than 29 dB of OPL in all cases. From a possible application point of view, up to 50 km reach is required by the recent Super PON proposal [50], [51] and similar long-reach PON [52], [53] alternatives. Our analysis for L > 50 km, i.e., 81.1 km and 106.2 km, is not intended for a practical PON system, since due to the high total fiber loss there is not enough power budget margin for splitter and connectors. ...
Passive Optical Networks (PON), able to operate at 50 Gbps per wavelength (), are under development and standardization, based on intensity-modulation (IM) and direct-detection (DD) systems. The next step in PON evolution will be driven by 5G/6G fronthauling capacity demands, and will require the development of 100 Gbps/ (and beyond) systems, which poses big challenges if maintaining the DD-format. In this contribution, we analyze a 100 Gbps/ PON architecture able to preserve the IM-DD approach at the Optical Network Unit (ONU), placing the complexity at the Optical Line Terminal (OLT), thanks to Digital Signal Processing (DSP). We experimentally demonstrate a 100 Gbps/ transmission using this architecture in the downstream (DS) direction. Chromatic dispersion digital pre-compensation (CD-DPC) in combination with an IQ Mach-Zehnder Modulator (IQ-MZM) is used at the transmitter (TX). Keeping the ONU DSP as simple as possible, as compared with current DSP proposals for 50 Gbps/ PON, is another main goal of this work. Adaptive equalization (AEQ) is used to correct for linear impairments, in addition to digital non-linear correction (NLC) at the receiver (RX). We compare two NLC approaches: a full Volterra Non-Linear Equalizer (VNLE) and a simpler NLC technique based on a square-root like function (SQRT). Operation over standard single-mode fiber (SMF) in C-band, achieving reaches from 0 km to 100 km and Optical Path Loss (OPL) values higher than 29 dB, are shown. The analyzed proposal is directly applicable to Terabit-capable wavelength division multiplexing (WDM)-PON, and can be extended to very high-speed Time Division Multiplexing (TDM)-PON and TWDM-PON, with some modifications discussed here.
... 28 We consider non-return-to-zero encoding signal format with OLT transmission power (T olt ) of 5 dBm at 10-Gbit∕s line rate, whereas avalanche photodiode (APD) photodetector with sensitivity (S onu ) of −30 dBm is used at the ONU. 29 With the given transmission technology, we use the following values for the given parameters: 28,30 ...
... Parameter with related values used for SNR calculation.[29][30][31][32] ...
... In fact, two 100G-PON solutions recently reported [14,15] have preserved O-band operation. However, proposals for opening again C-band (or L-band) operation would potentially be interesting, due to lower fiber attenuation and, when needed, availability of reliable EDFA amplifiers, as investigated for instance in the Super-PON standard proposal [19] and in general in long-reach TWDM-PON works [20]. Moreover, coexistence with legacy PON systems may be obtained more easily in the C-band, for example by reusing the Gigabit PON (G-PON) downstream wavelength assuming that, when the 100 Gbps/λ capacity will be needed, services will have already been migrated from the older G-PON system to any of the new PON generations. ...
... Interesting application scenarios for our proposal would be Point-to-Point (PtP) ultra-high speed application over PON (such as for fronthauling or big business users), or possible upgrades of the recently proposed Super-PON architecture [19,20] (even though with smaller power budget compared to the 41 dB required at current lower bit rate target of 10 Gbps/λ), where distance is increased up to 50 km, but the differential distance among users on the same PON tree is expected to be limited to a few km. Super-PON and similar long-reach architectures [26] envisions DWDM, thus typically requiring EDFA amplification and C+L band operation, so it will be CDlimited for any bit rate above 10 Gbps per wavelength. ...
We experimentally demonstrate a single-wavelength 100 Gbps downstream PON transmission aided by chromatic dispersion digital pre-compensation (CD-DPC) using simple Digital Signal Processing (DSP) Finite Impulse Response (FIR) filters in combination with an IQ Mach-Zehnder Modulator (IQ-MZM) at the transmitter side and direct-detection receiver at the Optical Network Unit (ONU). A reach of 50 km over standard single-mode fiber in C-band and an Optical Distribution Network (ODN) loss of 28.5 dB are achieved. Transmission of 50 and 125 Gbps over 50 km of fiber is also tested, achieving 32 dB and 24 dB of ODN loss, respectively. The complexity of the filters, the optimization of the main design parameters and the tolerance of the CD-DPC to the uncertainty of the exact accumulated link dispersion are analyzed in detail.
... Google Fiber is using a preliminary GPON-based version of Super-PON in the city of San Antonio, TX, USA [6]. Using Super PON sped up the initial deployment by 8 to 10 weeks and increased the first-year revenues by 36%. ...
Super-PON is a new standard being developed in both the IEEE and ITU-T that focuses on making FTTH deployments simpler. This paper overviews the standardization, an exemplary business case, and details of the world’s first Super-PON commercial deployment.
... Despite a wide range of proposals to change the access network (reflective PON [2], [3], SuperPON [4], [5], Long reach PON [6], [7]), in reality there has been little appetite to move away from standards based on a power-splitting ODN with a relatively modest reach and split ratio. The reasons for this include the simplicity of network deployment and management, the ease of upgrades, and backwards compatibility. ...
... This technique and the accompanying results were first presented, in part, in[40].5 In contrast to an NG-PON2 system, a tunable filter is therefore not required in the receiver.6 ...
In response to the ever-growing challenge of using conventional direct-modulation/direct-detection transceivers for upgrading passive optical networks, there has recently been a surge in interest in alternative transceiver technologies. Candidate systems include (simplified) coherent receivers, and digital signal processing in combination with direct detection. Beyond these mainstream solutions, other, more esoteric, system designs have been proposed, including networks based on general purpose signal processing hardware, split carrier transmitters, and ultra-wide bandwidth coherent receivers. Herein, we review these techniques and detail an experimental investigation of an ultra-wide bandwidth coherent receiver. It is found that the use of a dual-local oscillator receiver in an ultra-dense wavelength division multiplexed passive optical network (UDWDM-PON) enables the simultaneous detection of multiple upstream channels while efficiently using the complete receiver optoelectronic bandwidth.
In this work, a simulative analysis of 40 Gb/s downstream time and wavelength division multiplexing-passive optical network (TWDM-PON) for next-generation passive optical network second stage (NG-PON2) had been designed and demonstrated. The performance of three different wavelength plans in TWDM-PON are evaluated as the solution to NG-PON2 to support 40Gbit/s bandwidth requirement. A four 10-Gb/s TWDM-PON signals are stacked using four different wavelengths in the downstream direction and externally modulated. The system performance is observed using Bit Error Rate (BER) and Optical Signal-to-Noise Ratio (OSNR) with respect to the design parameters such as distance, number of users and received optical power. Thus, the proposed system was able to support 512 number of users and 80 km transmission distance. When the system is tested upon transmission of triple play services over 80km distance with 512 users, it is shown that BER of 8.9 × 10-10, 3.9 × 10-9 and 1.3 × 10-4 are achieved for data, voice and video, respectively.
We firstly demonstrated an active learning (AL)-based classifier for monitoring the entropy/rate of the PCS-based rate-flexible TWDM-CPON. For an 80-km 350-Gb/s/λ~450-Gb/s/ λ. downstream, AL-based scheme achieves 100%/95% entropy/rate identification accuracies corresponding to 25/5 Gbps tuning steps.
