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Journal ArticleDOI

Terabit+ (192 × 10 Gb/s) Nyquist Shaped UDWDM Coherent PON With Upstream and Downstream Over a 12.8 nm Band

15 Feb 2014-Journal of Lightwave Technology (IEEE)-Vol. 32, Iss: 4, pp 729-735
TL;DR: In this article, a bidirectional Terabit+ ultradense wavelength-division multiplexing (UDWDM) coherent passive optical network with Nyquist shaped 16-ary quadrature amplitude modulation is presented.
Abstract: In this paper, we numerically and experimentally demonstrate a bidirectional Terabit+ ultradense wavelength-division multiplexing (UDWDM) coherent passive optical network with Nyquist shaped 16-ary quadrature amplitude modulation, offering up to 10 Gb/s service capabilities per user/wavelength in a total spectrum of 12.8 nm over 40 km of standard single-mode fiber. This paper first demonstrates the capability of Nyquist pulse shaping to mitigate crosstalk arising from back-reflections and nonlinear effects in UDWDM networks with coherent transceivers. The latter part of the paper experimentally investigates the bidirectional transmission in terms of receiver sensitivity and nonlinear tolerance under different network transmission capacity conditions, e.g., number of users and bit rate per users.
Citations
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Journal ArticleDOI
TL;DR: In this paper, a set of architectures for coherent optical access networks is presented and the key attributes of each scenario are investigated, as a basis to decrease the cost of the local oscillator (LO) at customer side, and the possibility of using a low-cost laser as LO with real-time detection of a Nyquist-shaped differential quadrature phase-shift keying (DQPSK) signal using simple 8-bit digital signal processing (DSP) on a fieldprogrammable gate array.
Abstract: In this paper, we will address the benefits of the coherent detection in future optical access networks. The scarcity of the optical spectrum, the required flexibility, and constant evolution of requirements highlight the effectiveness of coherent techniques toward the future passive optical networks (PON). A set of architectures for coherent optical access networks will be presented and the key attributes of each scenario will be investigated. In addition, as a basis to decrease the cost of the local oscillator (LO) at customer side, we experimentally investigate the possibility of using a low-cost laser as LO with real-time detection of a Nyquist-shaped differential quadrature phase-shift keying (DQPSK) signal using simple 8-bit digital signal processing (DSP) on a field-programmable gate array. Moreover, we experimentally derive a set of optimized parameters and their impact on the network operation for coherent ultradense wavelength-division multiplexing (UDWDM) systems. The balance between the number of channels, power budget, and dynamic power range will be evaluated. Furthermore, we demonstrate a reconfigurable real-time receiver DSP for future flexible UDWDM-PON systems applying the DQPSK and D8PSK modulation formats. By reviewing some of the motivations for this technology, such as flexibility, spectral efficiency, as well as compatibility with software-defined networking, we show that this technology is approaching the required maturity.

82 citations

Journal ArticleDOI
TL;DR: In this article, a cost-effective coherent receiver is implemented by using the Alamouti polarization-time block coding scheme combined with heterodyne detection for the optical network unit in passive optical networks.
Abstract: In an access network based on a passive optical network architecture, coherent detection is attractive since it allows for high receiver sensitivity coupled with inherent frequency selectivity. Nevertheless, solutions employed in core networks are prohibitively complex and costly, requiring the optical complexity of the coherent receivers to be reduced to make them feasible for access networks. For monolithic integration, a key challenge is posed by the polarization beam splitter (PBS). If, however, the PBS is removed, the receiver needs to be redesigned to be insensitive to the incoming polarization state of the received signal. In this paper, we experimentally demonstrate a polarization-insensitive (i.e., polarization-independent) coherent receiver for the optical network unit in passive optical networks (PONs). The receiver consists of only a 3-dB coupler and a single-balanced photodiode such that the complexity is comparable to a direct detection receiver. The proposed cost-effective coherent receiver is implemented by using the Alamouti polarization-time block coding scheme combined with heterodyne detection. To verify the technique, the Alamouti-coded orthogonal frequency division multiplexing (OFDM) signal is rotated over the full Poincare sphere. Compared to the dual-polarization-OFDM signal operating at a net bit rate of 10 Gb/s per polarization (a gross bit rate of 10.7 Gb/s including a 7% FEC overhead), only a 0.6 dB sensitivity degradation is observed. The sensitivity at the FEC threshold, assumed to be $4\times 10^{-3}$ , is measured to be $-$ 41.5 dBm (56 photons-per-bit) on a 25-GHz grid. Following this, different channel spacings are investigated and the signal is transmitted over 80 km of standard single-mode fiber in a long-reach wavelength division multiplexed PON system. The loss budgets are found to be 43.0 and 42.8 dB for 50- and 25-GHz grids, respectively.

39 citations


Cites background from "Terabit+ (192 × 10 Gb/s) Nyquist Sh..."

  • ...Previous works have shown that this guard band is sufficient for upstream transmission [29], [30]....

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Journal ArticleDOI
TL;DR: This letter proposes and experimentally demonstrates a novel physical layer security method based on a piecewise chaotic permutation for orthogonal frequency division multiplexing (OFDM) passive optical networks that shows good resistance against illegal optical network units.
Abstract: This letter proposes and experimentally demonstrates a novel physical layer security method based on a piecewise chaotic permutation for orthogonal frequency division multiplexing (OFDM) passive optical networks. The piecewise parabolic chaotic map is adopted to generate chaotic permutation vectors, which enhance the physical layer security with a simple structure. An experiment with a 26.33-Gb/s encrypted optical OFDM signal is performed to demonstrate the proposed method. The results show good resistance against illegal optical network units and indicate that our method has the potential for use in secure optical access networks.

36 citations

Journal ArticleDOI
TL;DR: In this paper, the progress in ultra-dense wavelength division multiplexing passive optical network (UDWDM-PON) is reviewed by making use of the key attributes of this technology in the context of optical access and metro networks.

27 citations

Journal ArticleDOI
TL;DR: A real-time experimental demonstration of a long-reach coherent ultra-dense wavelength-division multiplexing (WDM)-passive optical network (PON) system with quadratic-amplitude modulation (QAM)-based dual-polarization optical transceivers using field-programmable gate array-based digital signal processing.
Abstract: We report a real-time experimental demonstration of a long-reach coherent ultra-dense wavelength-division multiplexing (WDM)-passive optical network (PON) system with quadratic-amplitude modulation (QAM)-based dual-polarization optical transceivers. Using field-programmable gate array-based digital signal processing, the transmission of 20-WDM channels in 2.5-GHz grid, employing both 2.5-Gb/s dual-polarization quadrature phase-shift keying (DP-QPSK) and 3.75-Gb/s DP-8PSK signals, is successfully demonstrated with bit-error rate in real-time. The performance is evaluated over 100-km standard single mode fiber in terms of receiver sensitivity and ODN power budget for both modulation formats, showing the feasibility of coherent PON scenarios using flexible dual-polarization strategies supported by software-defined transceivers.

26 citations

References
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Proceedings ArticleDOI
01 Dec 2006
TL;DR: The error vector magnitude (EVM) bit error rate (BER) and signal to noise ratio (SNR) and the fact that with such relationship it would be possible to predict or in cases substitute EVM in places of BER or even SNR is presented.
Abstract: In this paper, we relate the error vector magnitude (EVM) bit error rate (BER) and signal to noise ratio (SNR). We also present the fact that with such relationship it would be possible to predict or in cases substitute EVM in places of BER or even SNR. In doing so, we first define EVM with normalization so that the definition stands for multi-modulation systems, viz. binary phas shift keying (BPSK), quadrature phase shift keying (QPSK) etc. We also compare among the different performance metrics and show that EVM can be equivalently useful as signal to noise ratio and bit error rate. The relationships are based on stream based communication systems. A few Monte Carlo simulations are carried out to illustrate the performance of EVM based on these relationships.

621 citations

Journal ArticleDOI
TL;DR: General OFDM principles, including orthogonality, cyclic prefix use, frequency-domain equalization, and multiuser OFDMA are summarized, followed by an overview of various optical OFDM(A) transceiver architectures for next-generation PON.
Abstract: In this tutorial overview, the principles, advantages, challenges, and practical requirements of optical orthogonal frequency division multiplexing (OFDM)-based optical access are presented, with an emphasis on orthogonal frequency division multiple access (OFDMA) for application in next-generation passive optical networks (PON). General OFDM principles, including orthogonality, cyclic prefix use, frequency-domain equalization, and multiuser OFDMA are summarized, followed by an overview of various optical OFDM(A) transceiver architectures for next-generation PON. Functional requirements are outlined for high-speed digital signal processors (DSP) and data converters in OFDMA-PON. A techno-economic outlook for such a “software-defined,” DSP-based optical access platform is also provided.

511 citations

Journal ArticleDOI
TL;DR: New technologies that facilitate multiple access beyond 10 Gb/s time division multiple access (TDMA)-PONs will be reviewed, with particular focus on the motivation, key technologies, and deployment challenges.
Abstract: This paper reviews the future directions of next generation passive optical networks. A discussion on standardized 10 Gb/s passive optical network (PON) systems is first presented. Next, new technologies that facilitate multiple access beyond 10 Gb/s time division multiple access (TDMA)-PONs will be reviewed, with particular focus on the motivation, key technologies, and deployment challenges. The wavelength division multiplexed (WDM) PON will be discussed and in combination with TDMA, the hybrid WDM/TDMA PON will be reviewed in the context of improving system reach, capacity, and user count. Next, discussions on complementary high-speed technologies that provide improved tolerance to system impairments, capacity, and spectral efficiency will be presented. These technologies include digital coherent detection, orthogonal frequency division multiple access (OFDMA), and optical code division multiple access (OCDMA).

361 citations

Journal ArticleDOI
TL;DR: In this article, a technique to design the channel frequency allocation in order to minimize the crosstalk due to FWM is presented, which is obtained at the expense of some expansion of the system bandwidth.
Abstract: Crosstalk due to four-wave mixing (FWM) is the dominant nonlinear effect in long-haul multichannel optical communication systems employing dispersion-shifted fiber. A technique to design the channel frequency allocation in order to minimize the crosstalk due to FWM is presented. It is shown that suitable unequal channel separations can be found for which no four-wave mixing product term is superimposed on any of the transmitted channels. This is obtained at the expense of some expansion of the system bandwidth. Simulations are presented to show the effectiveness of this technique in a 10-channel, 10-Gb/s per channel, system. >

263 citations

Journal ArticleDOI
TL;DR: The analogy to optical orthogonal frequency division multiplexing is discussed and it is shown that using appropriate algorithms, Nyquist pulse shaped modulation formats can be encoded on a single wavelength at speeds beyond 100 Gbit/s in real-time.
Abstract: Nyquist sinc-pulse shaping provides spectral efficiencies close to the theoretical limit. In this paper we discuss the analogy to optical orthogonal frequency division multiplexing and compare both techniques with respect to spectral efficiency and peak to average power ratio. We then show that using appropriate algorithms, Nyquist pulse shaped modulation formats can be encoded on a single wavelength at speeds beyond 100 Gbit/s in real-time. Finally we discuss the proper reception of Nyquist pulses.

196 citations