We present theoretical and simulation results for the performance of asymmetrically-clipped optical OFDM (ACO-OFDM) and DC-biased optical OFDM (DCO-OFDM) in AWGN for intensity-modulated direct-detection systems. Constellations from 4 QAM to 1024 QAM are considered. For DCO-OFDM, the optimum bias depends on the constellation size which limits its performance in adaptive systems. ACO-OFDM requires less optical power for a given data rate than DCO-OFDM for all but the largest constellations and is better suited to adaptive systems as the same structure is optimum for all constellations.

Comparison of Asymmetrically Clipped Optical OFDM and DC-Biased Optical OFDM in AWGN

Orthogonal frequency-division multiplexing (OFDM) is a modulation technology that has been widely adopted in many new and emerging broadband wireless and wireline communication systems. Due to its capability to transmit a high-speed data stream using multiple spectral-overlapped lower-speed subcarriers, OFDM technology offers superior advantages of high spectrum efficiency, robustness against inter-carrier and inter-symbol interference, adaptability to server channel conditions, etc. In recent years, there have been intensive studies on optical OFDM (O-OFDM) transmission technologies, and it is considered a promising technology for future ultra-high-speed optical transmission. Based on O-OFDM technology, a novel elastic optical network architecture with immense flexibility and scalability in spectrum allocation and data rate accommodation could be built to support diverse services and the rapid growth of Internet traffic in the future. In this paper, we present a comprehensive survey on OFDM-based elastic optical network technologies, including basic principles of OFDM, O-OFDM technologies, the architectures of OFDM-based elastic core optical networks, and related key enabling technologies. The main advantages and issues of OFDM-based elastic core optical networks that are under research are also discussed.

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A Survey on OFDM-Based Elastic Core Optical Networking

We discuss coherent optical orthogonal frequency division multiplexing (CO-OFDM) as a suitable modulation technique for long-haul transmission systems. Several design and implementation aspects of a CO-OFDM system are reviewed, but we especially focus on phase noise compensation. As conventional CO-OFDM transmission systems are very sensitive to laser phase noise a novel method to compensate for phase noise is introduced. With the help of this phase noise compensation method we show continuously detectable OFDM transmission at 25.8 Gb/s data rate (20 Gb/s after coding) over 4160-km SSMF without dispersion compensation.

Coherent Optical 25.8-Gb/s OFDM Transmission Over 4160-km SSMF

We present experimental demonstrations using direct-detection and optical-orthogonal frequency division multiplexing (DD-OOFDM) for the compensation of chromatic dispersion in long-haul optical fiber links. Three transmitter designs of varying electrical and optical complexity are used for optical single sideband (OSSB) transmission and the theory behind each design is discussed. The data rates achieved for the three systems are 10, 12, and 20 Gbit/s for fiber distances between 320 and 400 km. A discussion of system overheads is provided together with simulations of the required optical signal-to-noise ratio (OSNR).

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Experimental Demonstrations of Electronic Dispersion Compensation for Long-Haul Transmission Using Direct-Detection Optical OFDM

There has been growing interest in coherent optical orthogonal frequency-division multiplexing (CO-OFDM) We aim to present the case that the time for CO-OFDM has come, in terms of the demand from today's ever-advancing optical networks and the availability of its underlying technologies We first lay out the signal processing aspect for CO-OFDM and then show a 2×2 multiple-input-multiple-output (MIMO) OFDM representation for the single-mode fiber optical channel Through numerical simulation and experimental demonstration, we further present and discuss various MIMO-OFDM systems focusing on their polarization-mode dispersion resilience Among those systems, the 2×1 MIMO-OFDM configuration incorporating polarization-time coding shows promise for optical access networks and broadcast networks Finally, another class of the frequency-domain equalization techniques, namely, incoherent or coherent optical single-carrier frequency-domain equalization (CO-SCFDE) is discussed and experimentally demonstrated

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Coherent optical OFDM: has its time come? [Invited]

Using discrete multi-tone modulation with up to 64-QAM mapping, 24-Gb/s transmission is experimentally demonstrated over 730 m of MMF by direct modulation of an 850-nm VCSEL and direct detection with a MMF receiver.

24-Gb/s Transmission over 730 m of Multimode Fiber by Direct Modulation of an 850-nm VCSEL Using Discrete Multi-Tone Modulation

The large bandwidth and ease of installation make POF a very attractive medium for low-cost broadband in-building networks, in which several independent sets of services are integrated. Adaptive subcarrier multiplexing can combine services with widely differing characteristics in a single POF network, among which high-capacity wireless LANs by deploying the Optical Frequency Multiplying radio-over-fibre technology. Introduction The booming demand for broadband services (such as video on demand, on-line multimedia games, peer-to-peer fast file transfer, ...) raises the need for a high bandwidth service delivery link, not only up to the end user’s residence, but also inside his premises. Simultaneously, due to the enormous volume, the installation and operation of these links need to be easy and cheap (preferably “do-ityourself” technology for non-skilled persons). In-building networks presently are deploying a wide range of transmission media: coaxial copper cables, twisted copper pair cables, power lines, freespace infrared links, IEEE 802.x wireless LAN links, etc. Each of these networks is optimized for a particular set of services; this complicates the introduction of new services and the creation of links between services (such as between video and data services). A single broadband multi-service network could provide an efficient solution to host all existing and upcoming services jointly. Optical fibre is an excellent candidate for implementing such a network, in particular multimode Polymer Optical Fibre (POF). POF is easy to splice and to connectorise due to its large core and non-fragile nature. Its ductility also facilitates the installation in ducts. As illustrated in Fig. 1, a POF network may constitute the backbone network that feeds fixed-wired services (such as GbE data services) as well as wireless services (e.g. IEEE 802.x) throughout the building. The residential gateway may coordinate the delivery of these services, and provide the bridging to the access network. With ranges up to a few kilometers, such an in-building network may cover not only a residential home, but also an apartment building, an airport departure hall, a hospital, an office building, etc. To simultaneously carry different sets of services (having different bandwidths, signal formats, quality-of-service (QoS), ...), cost-efficient signal multiplexing techniques compatible with multimode POF are needed. In this paper, two techniques for implementing a multi-service POF network will be discussed: adaptive subcarrier multiplexing which creates a number of independent frequency channels, and optical frequency multiplying which enables delivery of microwave wireless signals to simplified antenna sites over multimode POF. Coax cable network FD MD POF Twisted pair network

POF application in home systems and local systems

10.7 Gbit/s NRZ-signals are transmitted for the first time over 220 m of multimode 120 mum core-diameter perfluorinated graded-index polymer optical fiber using an MLSE equalizer.

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10.7 Gbit/s Transmission over 220 m Polymer Optical Fiber using Maximum Likelihood Sequence Estimation

By applying 16-, 32- and 64-QAM subcarrier modulation, 1.25 Gb/s transmission per channel via a 4.4 km silica multimode fibre was experimentally demonstrated. The passband region of the fibre was deployed by the subcarrier channel.

Transmission of 1.25 Gb/s per channel over 4.4 km silica multimode fibre using QAM subcarrier multiplexing

Wind-photovoltaic co-generation prediction and energy scheduling of low-carbon complex regional integrated energy system with hydrogen industry chain based on copula-MILP

J Jianming Zeng

Papers

24-Gb/s Transmission over 730 m of Multimode Fiber by Direct Modulation of an 850-nm VCSEL Using Discrete Multi-Tone Modulation

POF application in home systems and local systems

10.7 Gbit/s Transmission over 220 m Polymer Optical Fiber using Maximum Likelihood Sequence Estimation

Transmission of 1.25 Gb/s per channel over 4.4 km silica multimode fibre using QAM subcarrier multiplexing

Wind-photovoltaic co-generation prediction and energy scheduling of low-carbon complex regional integrated energy system with hydrogen industry chain based on copula-MILP