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A multi-layer next generation PON prototype has been built and tested, to show the feasibility of extended hybrid DWDM/TDM-XGPON FTTH networks with resilient optically-integrated ring-trees architecture, supporting broadband multimedia services. It constitutes a transparent common platform for the coexistence of multiple operators sharing the optical infrastructure of the central metro ring, passively combining the access and the metropolitan network sections. It features 32 wavelength connections at 10 Gbps, up to 1000 users distributed in 16 independent resilient sub-PONs over 100 km. This paper summarizes the network operation, demonstration and field trial results. (C) 2014 Elsevier Inc. All rights reserved., Peer Reviewed, Postprint (published version)

Digitally processed modulations formats such as Nyquist-WDM are investigated for implementation of future flexible optical networks, by using integrated photonic devices and moderate speed optoelectronics. We compare with other modulation formats as OFDM regarding complexity and adaptability to transceiver limitations., Peer Reviewed, Postprint (published version)

All-optical FDM grid generation and channel selection is experimentally demonstrated through optical signal processing. Full-duplex 10G/2×10G transmission with reflective ONUs is validated for 20dB budget and 25km reach. An optional 10Gb/s FDM/TDM mode is verified., Peer Reviewed, Postprint (published version)

The migration towards a 20 Gb/s quaternary TDM-PAM passive optical network with chirped and non-linear optical transmitters is experimentally studied. We show that a loss budget of 27.3 dB is compatible together with a packet power ratio of 10 dB between loud and soft ONU, Peer Reviewed, Postprint (published version)

Disseny de dos circuits optoelectrònics desplaçadors de la longitud d'ona per xarxes d'accés per fibra òptica (FTTH), [ANGLÈS] In this work it is presented the design and simulation of two different opto-electronic circuits to perform a wavelength shifting at optical network units (ONU) of Fiber To The Home (FTTH) networks. This significantly reduces Rayleigh backscattering impairment in passive optical networks that use one optical fiber per ONU with the same wavelength for both the upstream and downstream channels. The designs are developed with a generic technology platform for photonic integrated circuits based on InP (Indium Phosphide) substrate provided by PARADIGM project, finally providing the layout for both designs., [CASTELLÀ] En este trabajo se presenta el diseño y la simulación de dos circuitos opto-electrónicos diferentes para realizar un desplazamiento en longitud de onda en el terminal del usuario (Optical Network Unit, ONU) en redes de acceso de fibra óptica hasta el hogar (Fiber To The Home, FTTH). Este nuevo diseño de terminal de usuario elimina los efectos perniciosos del backscattering de Rayleigh en redes ópticas pasivas que usan una única fibra óptica y una única longitud de onda para los canales de subida y bajada de la transmisión. Los diseños se desarrollan con la plataforma tecnológica genérica de óptica integrada sobre InP (Indium Phosphide) proporcionada por PARADIGM, proporcionándose los layout de ambos diseños., [CATALÀ] En aquest treball es presenta el disseny i la simulació de dos circuits optoelectrònics diferents per realitzar un desplaçament en longitud d'ona en el terminal de l'usuari (Optical Network Unit, ONU) en xarxes d'accés de fibra òptica fins la llar (Fiber To The Home, FTTH). Aquest nou disseny del terminal d'usuari elimina els efectes nocius del backscattering de Rayleigh en xarxes òptiques passives que utilitzen una única fibra òptica i una única longitud d'ona per als canals de pujada i baixada de la transmissió. Els dissenys es desenvolupen amb la plataforma tecnològica genèrica d'òptica integrada sobre InP (Indium Phosphide) proporcionada per PARADIGM, proporcionant-se els layout d'ambdós dissenys.

A 20 Gb/s quaternary TDM-PAM passive optical network with chirped and non-linear optical transmitters is experimentally demonstrated. The migration from legacy TDM-PONs and the implications of using available 10 Gb/s components are analyzed. We show that a loss budget of 27.3 dB is compatible together with a packet power ratio of 10 dB between loud and soft optical network units., Peer Reviewed, Postprint (published version)

We propose and experimentally demonstrate a flexible wavelength division multiplexing/time division multiplexing network architecture for converged metro-access environment. Entire passiveness in the fiber plant is achieved with remote amplification in the signal distribution nodes along the metro ring and in the power splitters of the local access tree. We assist a traditional remote pumping scheme with a distributed pump provided by the optical network units and demonstrate that loss budgets beyond 30 dB can be supported. Data transmission of up to 10 Gb/s is evaluated in different deployment scenarios, reaching from a 78 km long reach rural to a dense 1:128 split/ urban configuration with field installed fibers, including also worst case resilience configurations., Peer Reviewed, Postprint (published version)

The tests with broadband multimedia services of the SARDANA multi-layer prototype prove the feasibility of scalable hybrid DWDM/TDM-PON FTTH networks with resilient optically-integrated ring-trees architecture., Peer Reviewed, Postprint (published version)

Projecte final de màster oficial fet en col.laboració amb Universitat Autònoma de Barcelona (UAB, Universitat de Barcelona (UB) i Institut de Ciències Fotòniques (ICFO), English: In this paper reflective SOAs are characterized for cost-efficient FTTH applications. The novel Nyquist WDM modulation format is investigated and implemented. An improvement of the bit error performance is achieved by a pre-distortion that compensates the bandwidth limitation of the reflective low-cost transmitter. The resulting modulation improves the BER and transmission speed. Furthermore, the format needs less signal processing compared to OFDM while reaching the same transmission rates., Castellano: En este trabajo se caracterizan SOAs reflectantes para aplicaciones económicas de FTTH. El formato novedoso de la modulación Nyquist WDM es investigado e implementado. Una mejora de la potencia del bit error está conseguido por una pre-distorsión que compense la limitación del ancho de banda del transmisor reflectante. La modulación resultante mejora la BER y la velocidad de transmisión. Además, el formato necesita menos procesamiento de la señal en comparación con OFDM, mientras alcanzan la misma velocidad de transmisión., Català: En aquest treball es caracteritzen SOAs reflectants per a aplicacions econòmiques de FTTH. El format nou de la modulació Nyquist WDM és investigat i implementat. Una millora de la potència del bit error està aconseguit per una pre-distorsió que compensi la limitació de l'ample de banda del transmissor reflectant. La modulació resultant millora la BER i la velocitat de transmissió. A més, el format necessita menys processament del senyal en comparació amb OFDM, mentre arriben a la mateixa velocitat de transmissió.

We theoretically investigate and experimentally demonstrate a scheme for all-optical carrier recovery in loopback access networks that avoids orthogonal or complex modulation formats for the downstream or upstream signals. The applied technique is based on a passive resonating circuit that is capable of recovering the optical carrier of the amplitude-shift-keyed downstream signal for remodulation with a reflective modulator as upstream transmitter enabling full-duplex 10 Gb/s operation. The scheme is compared with alternative pattern suppression techniques based on optical gain saturation and electro-optical feed-forward injection for the stringent requirements of next-generation access networks, namely, an extended loss budget and high upstream data rates. Operation at downstream modulation depths of ~3 dB is reported with the feed-forward approach, while higher modulation depths of up to 9 dB are demonstrated with the all-optical carrier recovery technique, for which the dependence on longer sequences of consecutive identical bits is investigated. Finally, the feasibility of the all-optical downstream cancelation technique for optical access networks is evaluated in a wavelength division multiplexed passive optical network, showing full-duplex transmission with margins of at least 9 dB., Peer Reviewed, Postprint (published version)

We present a scalable circuit that performs multichannel, all-optical wavelength conversion employing semiconductor optical amplifiers (SOAs) and a densely integrated TriPleX photonic chip. The TriPleX device performs chirp filtering and signal polarity inversion with on-chip signal processing. The chip includes a total number of 40 arrays of Si3 N4–SiO2 microring resonators, delay interferometers and heating elements. The total footprint of each array is 2.19mm2 and the power consumption per integrated heater is below 80 mW. We have interconnected the TriPleX chip with SOAs and we demonstrate experimentally 4x40 Gb/s, parallel and wavelength tunable wavelength conversion with power penalties of less than 3 dB., Peer Reviewed, Postprint (published version)

A network architecture for tree-like passive optical networks (PONs) with high splitting ratios is proposed and experimentally demonstrated. Splits >1000 are shown to be feasible thanks to a noise-powered amplifier that is built-in inside the power splitter. The proposed noise pumping technique recycles the natural amplified spontaneous emission (ASE) of a semiconductor optical amplifier at the customer premises, avoiding the use of an electrical power supply in the fiber plant. The impact of the location of this noise-powered extender box inside the signal distribution element of the tree is analyzed in terms of obtained signal gain, ASE accumulation among multiple extender boxes, and transmission performance. Finally, full-duplex transmission at 10 Gb/s with burst-mode upstream is demonstrated in a particular scenario with a split of 1:1000 and a loss budget of 39.5 dB, revealing that power margins >3 of dB can be provided., Peer Reviewed, Postprint (published version)

Doubling of the downstream rate by reusing the reflective upstream modulator is demonstrated. With just two photo-detectors, a RSOA and a power splitter at the ONU, a 20/10 Gbps mode can be provided per wavelength., Peer Reviewed, Postprint (published version)

Recent optical technologies are providing higher flexibility to next generation access networks: on the one hand, providing progressive FTTx and specifically FTTH deployment, progressively shortening the copper access network; on the other hand, also opening fixed-mobile convergence solutions in next generation PON architectures. It is provided an overview of the optical subsystems developed for the implementation of the proposed NG-Access Networks., Peer Reviewed, Postprint (published version)

A remote node design with a wavelength tuneable optical add/drop element is presented and experimentally demonstrated for application in a resilient ring+tree access network architecture. The flexibility of the network node regarding its allocation to the wavelength dimension of the network can be exploited to retain service delivery in case of subsystem failure at the optical line terminal (OLT) or optical network unit (ONU) as well as for an optimization of the transmission performance when switching from normal to resilient network operation in case of a ring fibre cut. A loss budget of 30 dB is compatible for the passive optical access network., Peer Reviewed, Postprint (published version)

Chirped IRZ downstream is used together with a delay interferometer and a RSOA at a low complexity ONU for full-duplex 10.5Gbps transmission on a single wavelength, supported by modulation format conversion and optical offset filtering., Peer Reviewed, Postprint (published version)

Simultaneous encoding of information in the optical phase and amplitude for upstream transmission is demonstrated with an integrated SOA/REAM of small form factor. The crosstalk penalties between the QAM tributaries are assessed and discussed., Peer Reviewed, Postprint (published version)

An upgrade at the physical layer regarding unbundling and dynamic bandwidth provisioning of a wavelength division multiplexed access network is presented. The capability of a reflective modulator to act as a photodetector is exploited and allows a tandem configuration to be used at the optical network unit (ONU) for flexible switching of the detection and modulation branch. Consequently, a mechanism for service operator selection and for dynamic bandwidth partitioning up to twice the nominal data rate is provided. The scheme is experimentally evaluated for different kinds of modulators and shows, together with a full-duplex transmission at 10 Gb/s, additional operation modes, featuring unidirectional downstream and upstream burst-mode transmission with up to 20 Gb/s for ONUs based on a combination of a semiconductor optical amplifier and a reflective electro-absorption modulator., Peer Reviewed, Postprint (published version)

El estudio e investigación en el campo de las redes ópticas de acceso han sido fomentadas en años recientes debido a la continua migración de Servicios multimedia que son ofrecidos a través de Internet. Aunque los dispositivos utilizados para implementar Fiber-to-the-Home (fibra a casa), que reemplazan las soluciones tradicionales basadas en cable de cobre, están basadas aún en micro-óptica, se puede prever una evolución hacia integración fotónica. Todavía queda la pregunta acerca de los diseños necesarios para este paso importante de integración, que debe ser optimizado en términos del desempeño de transmisión, eficiencia energética y costo con el fin de lograr todos los requerimientos de las redes fotónicas de siguiente generación. Como elemento más crítico en las redes de acceso ópticas es el equipo en los clientes, este trabajo se centra en éste. Los temes cubiertos abarcan una gama amplia e incluyen: el reciclado de longitudes de onda para transmisión de datos en full-dúplex a través de una sola frecuencia óptica; la generación de formatos de modulación avanzados con moduladores semiconductores de bajo costo y factor pequeño de integración; soporte de amplificación óptica a través de técnicas de sembrado y el soporte de funcionalidades de capes superiores en la capa física. Después de la prueba principal de las técnicas propuestas, se resaltan los beneficios, impedimentos y caminos de reemplazo hacia sistemas fotónicos multifuncionales a través de casos de estudio. Por su parte, los diseños más representativos se profundizan más sobre todo por su posibilidad de ser integrados fotónicamente., Optical access technology has experienced a boost in the last years, thanks to the continuously migrating multimedia services that are offered over the internet. Though the devices used for deploying Fiber-to-the-Home instead of traditional copper-based solutions are still based on micro-optics, an evolution towards photonic integration can be foreseen. What remains is the question about the exact designs for this important step of integration, which should be optimized in terms of transmission performance, energy efficiency and cost to address all requirements of next-generation photonic networks. As the most critical element in optical access, the customer premises equipment is in primary focus of this discussion. The covered topics span over a wide range and include wavelength recycling for full-duplex data transmission on a single optical frequency, the generation of advanced modulation formats with low-cost semiconductor modulators with small form factor, support for optical amplification by means of seeding techniques and the support of higher layer functionality at the physical layer. Next to the principal proof of the proposed techniques, the benefits, impediments and upgrade paths towards multifunctional photonic systems are highlighted in different case studies, while the most representative designs are further discussed in their capability of being photonically integrated., Postprint (published version)

Direct communication between ONUs is experimentally demonstrated with a tunable MG-Y laser in a ring+tree PON for 640 users, without passing electrically powered equipment., Peer Reviewed, Postprint (published version)

Wavelength shifting in PONs with downstream signal remodulation is presented, allowing upstream transmission over trees with 25km feeder and 1:32 split with penalties <2dB, originally Rayleigh backscattering limited. Side-mode suppression is analyzed for hybrid PONs., Peer Reviewed, Postprint (published version)

A method for extending the customer density via ASE-pumped splitters in the tree in a WDM/TDM-PON is presented. The influence of Rayleigh backscattering in the feeder is faced, originally prohibiting any upstream transmission., Peer Reviewed, Postprint (published version)

A receiver for optical frequency modulated signals, based on colorless demodulation and detection, is presented. An integrated combination of semiconductor optical amplifier (SOA) and reflective electroabsorption modulator (REAM) is designed to obtain a comb-like spectral detection function, replacing the typically required costly frequency discrimination filter. The spectral properties of the designed SOA/REAM chip are discussed and the reception of a 10-Gb/s optical frequency modulated downstream signal is demonstrated, proving the applicability as receiving optical subsystem in the customer premises equipment of fiber-to-the-home access networks with wavelength reuse for upstream transmission and no downstream crosstalk., Peer Reviewed, Postprint (published version)

Optical Network Units for Next-Generation Passive Optical Networks with wavelength reuse are investigated for asymmetrical 2.5 G/1.25 G and symmetrical 10 G/10 G down- and upstream data rates. The transmission performance was enhanced by a feed-forward cancellation circuitry adapted to an RSOA and an REAM used as remodulator. The range of downstream extinction ratios for error-free upstream transmission at BER of 10-10 was extended from 3 to 4 dB for the RSOA-based ONU and from 1.5 to 3 dB for the REAM-based ONU., Peer Reviewed, Postprint (published version)

An Optical Network Unit based on colourless detection of optical frequency modulated signals based on a combination of Semiconductor Optical Amplifier and Reflective Electroabsorption modulator with intensity remodulation for symmetrical full-duplex 10Gb/s transmission is demonstrated., Peer Reviewed, Postprint (published version)