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1174 KiB

Open AccessArticle

Energy-Saving Mechanism in WDM/TDM-PON Based on Upstream Network Traffic

by Paola Garfias, Marilet De Andrade, Massimo Tornatore, Anna Buttaboni, Sebastià Sallent and Lluís Gutiérrez

Photonics 2014, 1(3), 235-250; https://doi.org/10.3390/photonics1030235 - 12 Aug 2014

Cited by 12 | Viewed by 5602

Abstract

One of the main challenges of Passive Optical Networks (PONs) is the resource (bandwidth and wavelength) management. Since it has been shown that access networks consume a significant part of the overall energy of the telecom networks, the resource management schemes should also [...] Read more.

One of the main challenges of Passive Optical Networks (PONs) is the resource (bandwidth and wavelength) management. Since it has been shown that access networks consume a significant part of the overall energy of the telecom networks, the resource management schemes should also consider energy minimization strategies. To sustain the increased bandwidth demand of emerging applications in the access section of the network, it is expected that next generation optical access networks will adopt the wavelength division/time division multiplexing (WDM/TDM) technique to increase PONs capacity. Compared with traditional PONs, the architecture of a WDM/TDM-PON requires more transceivers/receivers, hence they are expected to consume more energy. In this paper, we focus on the energy minimization in WDM/TDM-PONs and we propose an energy-efficient Dynamic Bandwidth and Wavelength Allocation mechanism whose objective is to turn off, whenever possible, the unnecessary upstream traffic receivers at the Optical Line Terminal (OLT). We evaluate our mechanism in different scenarios and show that the proper use of upstream channels leads to relevant energy savings. Our proposed energy-saving mechanism is able to save energy at the OLT while maintaining the introduced penalties in terms of packet delay and cycle time within an acceptable range. We might highlight the benefits of our proposal as a mechanism that maximizes the channel utilization. Detailed implementation of the proposed algorithm is presented, and simulation results are reported to quantify energy savings and effects on network performance on different network scenarios. Full article

(This article belongs to the Special Issue All Optical Networks for Communications)

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374 KiB

Open AccessArticle

Polarization-Independent All-Optical Regenerator for DPSK Data

by Valeria Vercesi, Claudio Porzi, Giampiero Contestabile and Antonella Bogoni

Photonics 2014, 1(2), 154-161; https://doi.org/10.3390/photonics1020154 - 27 May 2014

Cited by 4 | Viewed by 5310

Abstract

We demonstrate polarization-independent simultaneous all-optical phase-preserving amplitude regeneration and wavelength conversion of NRZ differential phase shift keying (DPSK) data by four-wave mixing (FWM) in a semiconductor optical amplifier (SOA). The dependence upon polarization state of the signals is eliminated by using a co-polarized [...] Read more.

We demonstrate polarization-independent simultaneous all-optical phase-preserving amplitude regeneration and wavelength conversion of NRZ differential phase shift keying (DPSK) data by four-wave mixing (FWM) in a semiconductor optical amplifier (SOA). The dependence upon polarization state of the signals is eliminated by using a co-polarized dual-pump architecture. Investigation on the regenerative capability vs. pumps detuning shows significant BER threshold margin improvement over 6 nm conversion range. Full article

(This article belongs to the Special Issue All Optical Networks for Communications)

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387 KiB

Open AccessArticle

Photonic-Based RF Transceiver for UWB Multi-Carrier Wireless Systems

by Filippo Scotti, Francesco Laghezza, Paolo Ghelfi, Sergio Pinna, Giovanni Serafino and Antonella Bogoni

Photonics 2014, 1(2), 146-153; https://doi.org/10.3390/photonics1020146 - 22 May 2014

Cited by 5 | Viewed by 6086

Abstract

In this paper an all-optical system exploitable as the core structure for a photonic-based RF transceiver is presented. The proposed scheme is able to simultaneously perform either up- or down-conversion of multiple frequency Ultra-Wide Band (UWB) RF signals, employing a single Mode-Locking Laser [...] Read more.

In this paper an all-optical system exploitable as the core structure for a photonic-based RF transceiver is presented. The proposed scheme is able to simultaneously perform either up- or down-conversion of multiple frequency Ultra-Wide Band (UWB) RF signals, employing a single Mode-Locking Laser (MLL). The system has been experimentally demonstrated and tested by up- and down-converting orthogonal frequency division multiplexing (OFDM) signals over a bandwidth of about 4 GHz. The scheme’s performance has been validated by measuring the error vector magnitude (EVM) of the OFDM signals over the whole considered RF spectrum (from 5 GHz to 26.5 GHz), both in up-conversion and in down-conversion. The measurements show negligible power penalties, lower than 0.5 dB. Since the proposed scheme can act either as an up- or down-converter, and it is composed by easily integratable devices, two identical structures can be combined on a single integrated platform, sharing a single MLL, to build a compact and efficient UWB transceiver. Full article

(This article belongs to the Special Issue All Optical Networks for Communications)

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503 KiB

Open AccessArticle

Optical Backplane Based on Ring-Resonators: Scalability and Performance Analysis for 10 Gb/s OOK-NRZ

by Giuseppe Rizzelli, Domenico Siracusa, Guido Maier, Maurizio Magarini, Mehmood Alam and Andrea Melloni

Photonics 2014, 1(2), 131-145; https://doi.org/10.3390/photonics1020131 - 12 May 2014

Viewed by 7772

Abstract

The use of architectures that implement optical switching without any need of optoelectronic conversion allows us to overcome the limits imposed by today’s electronic backplane, such as power consumption and dissipation, as well as power supply and footprint requirements. We propose a ring-resonator [...] Read more.

The use of architectures that implement optical switching without any need of optoelectronic conversion allows us to overcome the limits imposed by today’s electronic backplane, such as power consumption and dissipation, as well as power supply and footprint requirements. We propose a ring-resonator based optical backplane for router line-card interconnection. In particular we investigate how the scalability of the architecture is affected by the following parameters: number of line cards, switching-element round-trip losses, frequency drifting due to thermal variations, and waveguide-crossing effects. Moreover, to quantify the signal distortions introduced by filtering operations, the bit error rate for the different parameter conditions are shown in case of an on-off keying non-return-to-zero (OOK-NRZ) input signal at 10 Gb/s. Full article

(This article belongs to the Special Issue All Optical Networks for Communications)

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590 KiB

Open AccessArticle

Optical Systems for Ultra-High-Speed TDM Networking

by Michael Galili, Hao Hu, Hans Christian Hansen Mulvad, Ashenafi Kiros Medhin, Anders Clausen and Leif Katsuo Oxenløwe

Photonics 2014, 1(2), 83-94; https://doi.org/10.3390/photonics1020083 - 25 Apr 2014

Cited by 3 | Viewed by 5235

Abstract

This paper discusses key results in the field of high speed optical networking with particular focus on packet-based systems. Schemes for optical packet labeling, packet switching and packet synchronization will be discussed, along with schemes for optical clock recovery, channel identification and detection [...] Read more.

This paper discusses key results in the field of high speed optical networking with particular focus on packet-based systems. Schemes for optical packet labeling, packet switching and packet synchronization will be discussed, along with schemes for optical clock recovery, channel identification and detection of ultra-high-speed optical signals. Full article

(This article belongs to the Special Issue All Optical Networks for Communications)

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903 KiB

Open AccessArticle

The Escape of Sisyphus or What “Post NG-PON2” Should Do Apart from Neverending Capacity Upgrades

by Martin Maier

Photonics 2014, 1(1), 47-66; https://doi.org/10.3390/photonics1010047 - 21 Mar 2014

Cited by 7 | Viewed by 5565

Abstract

The primary design goal of (r)evolutionary NG-PON1&2 was the provisioning of an ever increasing capacity to cope with video-dominated traffic and handle the explosion of mobile data traffic by means of offloading. Recently, however, questions on the future of “post NG-PON2” have surfaced [...] Read more.

The primary design goal of (r)evolutionary NG-PON1&2 was the provisioning of an ever increasing capacity to cope with video-dominated traffic and handle the explosion of mobile data traffic by means of offloading. Recently, however, questions on the future of “post NG-PON2” have surfaced whether to shift its research focus to business and operation related aspects and move access technology into a substantially different direction than continued capacity upgrades. In fact, recent studies indicate that ultimately the major factor limiting the performance of 4G mobile networks is latency rather than capacity of the backhaul. In this paper, we review recently proposed low-latency techniques for NG-PONs that require architectural modifications at the remote node or distribution fiber level and highlight advanced network coding and real-time polling based low-latency techniques that can be implemented in software, enable NG-PONs to carry higher traffic loads and thereby extend their lifetime, and maintain the passive nature of existent optical distribution networks. Furthermore, we elaborate on emerging trends and open challenges for future post NG-PON2 research. To better understand their true potential, we put them into a wider non-technical and historical perspective leading up to a sustainable Third Industrial Revolution (TIR) economy and its underlying Energy Internet. Full article

(This article belongs to the Special Issue All Optical Networks for Communications)

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771 KiB

Open AccessArticle

Signal to Noise Ratio (SNR) Enhancement Comparison of Impulse-, Coding- and Novel Linear-Frequency-Chirp-Based Optical Time Domain Reflectometry (OTDR) for Passive Optical Network (PON) Monitoring Based on Unique Combinations of Wavelength Selective Mirrors

by Christopher M. Bentz, Lars Baudzus and Peter M. Krummrich

Photonics 2014, 1(1), 33-46; https://doi.org/10.3390/photonics1010033 - 20 Mar 2014

Cited by 7 | Viewed by 12282

Abstract

We compare optical time domain reflectometry (OTDR) techniques based on conventional single impulse, coding and linear frequency chirps concerning their signal to noise ratio (SNR) enhancements by measurements in a passive optical network (PON) with a maximum one-way attenuation of 36.6 dB. A [...] Read more.

We compare optical time domain reflectometry (OTDR) techniques based on conventional single impulse, coding and linear frequency chirps concerning their signal to noise ratio (SNR) enhancements by measurements in a passive optical network (PON) with a maximum one-way attenuation of 36.6 dB. A total of six subscribers, each represented by a unique mirror pair with narrow reflection bandwidths, are installed within a distance of 14 m. The spatial resolution of the OTDR set-up is 3.0 m. Full article

(This article belongs to the Special Issue All Optical Networks for Communications)

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Review

Jump to: Research

747 KiB

Open AccessReview

Self-Homodyne Detection in Optical Communication Systems

by Benjamin J. Puttnam, Ruben S. Luís, José Manuel Delgado Mendinueta, Jun Sakaguchi, Werner Klaus, Yukiyoshi Kamio, Moriya Nakamura, Naoya Wada, Yoshinari Awaji, Atsushi Kanno, Tetsuya Kawanishi and Tetsuya Miyazaki

Photonics 2014, 1(2), 110-130; https://doi.org/10.3390/photonics1020110 - 06 May 2014

Cited by 56 | Viewed by 13008

Abstract

We review work on self-homodyne detection (SHD) for optical communication systems. SHD uses a transmitted pilot-tone (PT), originating from the transmitter laser, to exploit phase noise cancellation at a coherent receiver and to enable transmitter linewidth tolerance and potential energy savings. We give [...] Read more.

We review work on self-homodyne detection (SHD) for optical communication systems. SHD uses a transmitted pilot-tone (PT), originating from the transmitter laser, to exploit phase noise cancellation at a coherent receiver and to enable transmitter linewidth tolerance and potential energy savings. We give an overview of SHD performance, outlining the key contributors to the optical signal-to-noise ratio penalty compared to equivalent intradyne systems, and summarize the advantages, differences and similarities between schemes using polarization-division multiplexed PTs (PDM-SHD) and those using space-division multiplexed PTs (SDM-SHD). For PDM-SHD, we review the extensive work on the transmission of advanced modulation formats and techniques to minimize the trade-off with spectral efficiency, as well as recent work on digital SHD, where the SHD receiver is combined with an polarization-diversity ID front-end receiver to provide both polarization and modulation format alignment. We then focus on SDM-SHD systems, describing experimental results using multi-core fibers (MCFs) with up to 19 cores, including high capacity transmission with broad-linewidth lasers and experiments incorporating SDM-SHD in networking. Additionally, we discuss the requirement for polarization tracking of the PTs at the receiver and path length alignment and review some variants of SHD before outlining the future challenges of self-homodyne optical transmission and gaps in current knowledge. Full article

(This article belongs to the Special Issue All Optical Networks for Communications)

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798 KiB

Open AccessReview

Transport Schemes for Fiber-Wireless Technology: Transmission Performance and Energy Efficiency

by Christina Lim, Yizhuo Yang and Ampalavanapillai Nirmalathas

Photonics 2014, 1(2), 67-82; https://doi.org/10.3390/photonics1020067 - 16 Apr 2014

Cited by 9 | Viewed by 6696

Abstract

Fiber-wireless technology has been actively researched as a potential candidate for next generation broadband wireless signal distribution. Despite the popularity, this hybrid scheme has many technical challenges that impede the uptake and commercial deployment. One of the inherent issues is the transport of [...] Read more.

Fiber-wireless technology has been actively researched as a potential candidate for next generation broadband wireless signal distribution. Despite the popularity, this hybrid scheme has many technical challenges that impede the uptake and commercial deployment. One of the inherent issues is the transport of the wireless signals over a predominantly digital optical network in today’s telecommunication infrastructure. Many different approaches have been introduced and demonstrated with digitized RF transport of the wireless signals being the most compatible with the existing optical fiber networks. In this paper, we review our work in the area of digitized RF transport to address the inherent issues related to analog transport in the fiber-wireless links and compare the transmission performance and energy efficiency with the other transport strategies. Full article

(This article belongs to the Special Issue All Optical Networks for Communications)

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