Time- and Wavelength-Division Multiplexed Passive Optical Network (TWDM-PON) for Next-Generation PON Stage 2 (NG-PON2)

Recent development on time and wavelength-division multiplexed passive optical network (TWDM-PON) for next-generation passive optical network stage 2 (NG-PON2)

Time and wavelength division multiplexed passive optical networks (TWDM-PONs) have been chosen by the Full Service Access Network (FASN) group as the primary solution for next-generation passive optical network stage-2(NG-PON2). The key components in TWDM-PON are the tunable receivers and tunable transmitters at the ONU. However, most of the dynamic wavelength assignment algorithms are not considering the tuning time. In reality, wavelength tuning will limit channel utilization and increase packet delay. In this paper, we proposed a minimum wavelength tuning (MWT) scheme which is reducing the frequency of wavelength tuning. Simulation results show that MWT scheme can effectively reduce packet delay and improve the channel utilization.

Time and wavelength division multiplexed passive optical network (TWDM-PON) is one of the most promising candidates of the next generation optical access system beyond 10Gb/s. The TWDM-PON system stacks multiple 10Gigabit PONs (XG-PONs) by employing tunable transmitters and tunable receivers at ONUs. In the TWDM-PON media access control (MAC) layer, wavelength management becomes a critical issue of resource sharing and assignment. In this paper, we propose a mechanism to manage multiple wavelengths in the TWDM-PON system. We also model this problem by using multiprocessor scheduling analysis. Two types of heuristic algorithms have been proposed to relax the NP-hard complexity problem and promote online implementation. A TWDM-PON prototype system has been built to evaluate its performance. The proposed two algorithms have been implemented in the prototype system to test their wavelength tuning cost and load balancing capability. Analysis and test demonstrate salient results. To the authors' best knowledge, this is the first work of implementing the multiple wavelength management mechanism in an actual TWDM-PON prototype system, and the reported results in this paper benefit the ongoing next generation passive optical network stage 2 (NG-PON2) research and standards efforts.

A high data transmission rate is the main requirement for next-generation telecommunication networks. A design for a 40 Gb/s time and wavelength-division multiplexed passive optical network (TWDM-PON) for next-generation passive optical network stage 2 is presented. The use of a modulated grating Y-branch (MG-Y) laser is proposed as an upstream tunable colorless laser source to upgrade the optical network unit. The electronically tuned MG-Y externally modulated laser with a 10 Gb/s modulation rate is applied to a TWDM-PON and presented across a 3.2-nm tuning range. The performance of the proposed laser is analyzed in terms of bit error rate, eye diagram, and optical signal-to-noise ratio. The proposed TWDM-PON achieved an aggregated data rate of 40 Gb/s along 40 km of bidirectional fiber at a 1:128 splitting ratio without amplification and dispersion compensation.

Traffic-aware energy saving scheme with modularization supporting in TWDM-PON

Time- and wavelength-division multiplexed passive optical network (TWDM-PON) has been selected by full service access networks as a primary solution for next generation PON stage 2 in April 2012. In this letter, we propose and demonstrate a symmetric 40-Gb/s TWDM-PON with 39-dB power budget. A reflective semiconductor optical amplifier is used in optical network unit as a pre-amplifier to enhance the sensitivity of downstream signals. For the upstream direction, a thermally-tuned directly modulated laser with 10-Gb/s modulation rate is used as upstream colorless source, and a chirp management filter is employed in optical line terminal to mitigate chromatic dispersion therefore enabling fiber transmission. Symmetric 40-Gb/s TWDM-PON is experimentally demonstrated with a power budget of 39 dB, which could support 25-km fiber transmission and 1:1000 splitting ratio.

The transmission of symmetric 40 Gb/s TWDM-based NG-PON2 utilizing delay interferometer (DI) for RSOA bandwidth enhancement

Novel ring-based architecture for TWDM-PON with high reliability and flexible extensibility

To improve the performance of broadband access networks Full Service Access Network selected Time and wavelength division multiplexed Passive Optical Network (TWDM-PON) as the primary solution for next-generation optical access (Next-Generation Passive Optical Networks 2 (NGPON2)). This paper reviews the recent progress in this access technology. Different possible solutions for the-next generation access are explained. Comparison of the different TWDM architectures experimentally demonstrated so far is made considering the large split, long reach and high capacity requirements of NGPON2. Major technical challenges in implementing the TWDM networks are discussed. Possible options for designing hybrid wireless–wireline architectures are explained taking care of the high bandwidth provided by the optical networks and high mobility of wireless networks. Also an integrated optical wireless architecture is suggested using TWDM-PON as an optical backhaul.

The motivation of this study springs from the need of exploiting the advantages of high data rate and increased mobility of the transmitted signal in the Next Generation Passive Optical Network stage 2 (NG-PON2) incorporated into Radio over Fiber (RoF) system. Nonetheless, such system is prone to degradation due to the nonlinear effects, namely, the non-linear impairments. Accordingly, this study suggests a design for a full-duplex NG-PON2-RoF system and it investigates the impact of the nonlinear effects on the performance of system, such as; Self-Phased Modulation (SPM), Cross-Phase Modulation (XPM), and Four-Wave Mixing (FWM). However, these effects would result in a significant data loss in Time and Wavelength Division Multiplexing-Passive Optical Network (TWDM-PON). To achieve the intended purpose of this investigation, both the performance of the suggested system and the nonlinear effects of SPM, XPM, and FWM are measured with reference to the qualitative parameters, such as; Bit Error Rate (BER), Q-Factor, Power link Budget, and the Eye-diagram. The results show that the system performs efficiently; however, in the presence of the nonlinear effects, the performance of the systems degrades significantly affecting the signal quality. It is worth noting that the FWM effect yields the most negative impact followed by the XPM, and the SPM effect yields the least significant impact on the system. Also, the system yields the capacity of transmitting range of 20-100 Km, and it results in data rate of 40-80 Gbps. The proposed system is simulated using the software Optisystem 15.

The exponential growth of high-speed broadband services, an increase in the number of end-users, high bandwidth, and massive data rate demand innovative and emerging points to a multipoint network that satisfies the need for next-generation passive optical access network (NG-PON). Next-generation passive optical access network stage 2 (NG-PON2)-based time and wavelength division multiplexing passive optical network (TWDM-PON) are mostly considered as the most promising optical access candidate due to its high-speed services, low power consumption, back-to-back compatibility, and cost-effectiveness. In this paper, the eight wavelengths-based bidirectional 80/20 Gbps TWDM-PON system using return to zero (RZ), non-return to zero (NRZ), and carrier suppressed return to zero (CSRZ) data modulation formats have been proposed and analyzed by varying input power, transmission distance, and bit rate. Further, the system is evaluated in terms of minimum bit error rate (BER), quality factor (Q factor), received optical power (dBm), eye diagrams, and eye height. It has been observed that the most appropriate modulation format for downstream transmission is NRZ while for upstream transmission, the most suitable modulation formats are RZ and NRZ.

The full service access network (FSAN) task group meeting was held in April 2012, where they agreed to adopt time and wavelength division multiplexed passive optical network (TWDM-PON) as a primary solution to NG-PON2. Major requirements includes at least 40 Gbit/s aggregate rate in downstream, 1:64 split ratio, 40 km differential reach, and at least 1 Gb/s access rate per optical network unit (ONU). In this paper, a performance analysis will be carried out for downstream 4-wavelengths group selection from S-band, L-band, and C-band. A comparison for optimal transmitter design is also investigated among probable options of chirp managed laser diode, Lithium Niobate (LiNbo3) Mach Zehnder modulator, besides examining tunable transceivers in contrary to remotely fed colorless ONUs.

The paper describes some relevant solutions for Next Generation Access Network (NGAN, or NGN), considering evolution from copper legacy network to optical access network (PON, Passive Optical Network) and analysing pros and cons of several PON solutions (TDM-PON, WDM-PON, TWDM and OFMD-PON) as well as potential convergence/coexistence scenarios.

Time- and wavelength-division multiplexed passive optical networks (TWDM-PONs) have been selected by the full services access network community as the most suitable technology for next-generation optical access networks. A key technology in TWDM-PON is the colorless optical network unit transceiver. This paper proposes a flexible, tunable optical transceiver that uses directly modulated tunable lasers. Using a field-programmable gate array (FPGA), programmable reconfigurations and testing capabilities can be embedded into the transceiver in order to implement wavelength control, signal generation, pre-emphasis for upstream, and a bit error rate (BER) test for the downstream. To ensure high-quality signal generation at different bitrates, impedance matching between the laser driver circuit and the laser diodes is optimized. Using the proposed transceiver, three-section-distributed Bragg reflector tunable lasers at or below 2.5 Gb/s direct modulation through a 40-km standard mode fiber transmission were successfully implemented.

الملخص: في هذا العمل، تم تصميم وعرض تحليل محاكاة للشبكة الضوئية السلبية لتعدد الإرسال بتقسيم الطول الموجي 40 جيجابت/ثانية (TWDM-PON) للمرحلة الثانية من الشبكة الضوئية المنفعلة من الجيل التالي (NG-PON2). يتم تقييم أداء ثلاث خطط مختلفة للأطوال الموجية في TWDM-PON كحل لـ NG-PON2 لدعم متطلبات النطاق الترددي 40 جيجابت/ثانية. يتم تكديس أربع إشارات TWDM-PON بسرعة 10 جيجابت/ثانية باستخدام أربعة أطوال موجية مختلفة في اتجاه المصب ويتم تعديلها خارجيًا. تتم ملاحظة أداء النظام باستخدام معدل خطأ البت (BER) ونسبة الإشارة إلى الضوضاء البصرية (OSNR) فيما يتعلق بمعلمات التصميم مثل المسافة وعدد المستخدمين والطاقة الضوئية المستقبلة. وبذلك تمكن النظام المقترح من دعم 512 عدد من المستخدمين ومسافة إرسال 80 كم. عندما يتم اختبار النظام عند إرسال خدمات التشغيل الثلاثي على مسافة 80 كم مع 512 مستخدمًا، فقد تبين أنه تم تحقيق معدل BER قدره 8.9 × 10-10 و3.9 × 10-9 و1.3 × 10-4 للبيانات والصوت والفيديو، على التوالى.