Amj Ton Koonen

Photonic Home Area Networks

Indoor networks have to carry a large variety of services, with widely differing needs regarding, e.g., bandwidth, quality of service, and reliability. They have to support both wirebound and wireless connectivity, at low costs and low energy consumption levels. This paper gives an overview of trends and recent research results in the area of photonic solutions for indoor networks. It reviews the architectures, economics, and techniques for converged optical fiber indoor networks, which are cost- and energy-efficient, and compares them with current copper-based solutions. Particular attention is given to high-capacity multimode (plastic) optical fiber techniques, radio-over-fiber techniques, techniques for providing capacity on demand, and optical wireless communication techniques. An evolution perspective is outlined how the growing indoor communication demands can be met by introducing these powerful techniques and network architectures.

Discrete Multitone Modulation for Maximizing Transmission Rate in Step-Index Plastic Optical Fibers

The use of standard 1-mm core-diameter step-index plastic optical fiber (SI-POF) has so far been mainly limited to distances of up to 100 m and bit-rates in the order of 100 Mbit/s. By use of digital signal processing, transmission performance of such optical links can be improved. Among the different technical solutions proposed, a promising one is based on the use of discrete multitone (DMT) modulation, directly applied to intensity-modulated, direct detection (IM/DD) SI-POF links. This paper presents an overview of DMT over SI-POF and demonstrates how DMT can be used to improve transmission rate in such IM/DD systems. The achievable capacity of an SI-POF channel is first analyzed theoretically and then validated by experimental results. Additionally, first experimental demonstrations of a real-time DMT over SI-POF system are presented and discussed.

Bidirectional radio-over-fiber link employing optical frequency multiplication

We propose a bidirectional radio-over-fiber link consisting of an optical downlink transmission employing the optical frequency multiplication principle, a remote local oscillator (LO) generation, a remote down-conversion of the radio-frequency uplink signals, and an optical uplink transmission employing intensity modulation-direct detection. Experiments demonstrate the optical up-conversion of 64-level quadrature amplitude modulated radio signals to 17.8 GHz after transmission over 4.4 km of multimode fiber, 12.5 and 25 km of single-mode fiber in the downlink; the uplink performance is evaluated in terms of down-conversion loss employing the optically generated LO.

High-speed transmission over multimode fiber using discrete multitone modulation

Focus Issue: Orthogonal-Frequency-Division Multiplexed Communications Systems and Networks Discrete multitone (DMT) modulation is a subclass of the more general orthogonal-frequency-division multiplexing, where the output of the inverse fast Fourier transform modulator is real instead of complex-valued. Therefore, no in-phase and quadrature modulation onto an RF carrier is required. As a result, broadband, high-frequency, analog RF components are omitted, reducing system complexity and costs. We give an overview of important issues such as synchronization and peak-to-average power that should be considered when DMT is employed in an intensity-modulated direct-detection multimode fiber (MMF) link. Experimental results showing 24Gbits/s transmission over silica MMF and 8Gbits/s transmission over the standard step-index polymer optical fiber (SI-POF) are presented, demonstrating the potential of DMT to enable high-speed transmission over MMF using only low-bandwidth transceivers.

Design Considerations for a Transparent Mode Group Diversity Multiplexing Link

Mode group diversity multiplexing (MGDM) is an optical multiple-input-multiple-output technique that aims at creating independent communication channels over a multimode fiber, using subsets of propagating modes. This letter deals with the analysis of an MGDM point-to-point link, transparent to the transmission format. The geometry of a mode-group selective multi/demultiplexer is optimized in order to minimize the crosstalk among the channels. The power penalty is calculated when a zero-forcing algorithm is used to mitigate the crosstalk

47.4 Gb/s Transmission Over 100 m Graded-Index Plastic Optical Fiber Based on Rate-Adaptive Discrete Multitone Modulation

We experimentally demonstrate a bit-rate of 47.4 Gb/s over 100 m of perfluorinated multimode graded-index plastic optical fiber (GI-POF) by exploiting discrete multitone (DMT) modulation with rate-adaptive bit-loading. The maximum achieved aggregate bit rate is 51.8 Gb/s including DMT transmission overhead (cyclic prefix and preambles) and the standard of 7% of forward-error-correction (FEC) overhead. This is achieved over an intensity-modulated direct-detection (IM-DD) link using a directly-modulated DFB laser (1300-nm) and a multimode fiber-coupled photodetector with a large diameter of 25-¿m. The bandwidth requirement is only 12 GHz due to the use of spectral-efficient modulation formats of up to 64-QAM.

Recent Results From the EU POF-PLUS Project: Multi-Gigabit Transmission Over 1 mm Core Diameter Plastic Optical Fibers

Recent activity to achieve multi-gigabit transmission over 1 mm core diameter graded-index and step-index plastic optical fibers for distances up to 50 meters is reported in this paper. By employing a simple intensity-modulated direct-detection system with pulse amplitude or digital multi-tone modulation techniques, low-cost transceivers and easy to install large-core POFs, it is demonstrated that multi-gigabit transmission up to 10 Gbit/s over 1-mm core diameter POF infrastructure is feasible. The results presented in this paper were obtained in the EU FP7 POF-PLUS project, which focused on applications in different scenarios, such as in next-generation in-building residential networks and in datacom applications.

Mode-multiplexed transmission over conventional graded-index multimode fibers

We present experimental results for combined mode-multiplexed and wavelength multiplexed transmission over conventional graded-index multimode fibers. We use mode-selective photonic lanterns as mode couplers to precisely excite a subset of the modes of the multimode fiber and additionally to compensate for the differential group delay between the excited modes. Spatial mode filters are added to suppress undesired higher order modes. We transmit 30-Gbaud QPSK signals over 60 WDM channels, 3 spatial modes, and 2 polarizations, reaching a distance of 310 km based on a 44.3 km long span. We also report about transmission experiments over 6 spatial modes for a 17-km single-span experiment. The results indicate that multimode fibers support scalable mode-division multiplexing approaches, where modes can be added over time if desired. Also the results indicate that mode-multiplexed transmission distance over 300 km are possible in conventional multimode fibers.

Mode-selective spatial filtering for increased robustness in a mode group diversity multiplexing link

We propose a very simple optical method to reduce the cross talk among the channels of a mode group diversity multiplexing (MGDM) link. MGDM is an intensity modulation, direct detection, multiple-input, multiple-output technique that creates independent communication channels over a multimode fiber (MMF). The cross talk among the channels is mitigated electronically. However, by properly employing a lens between the output of a graded-index MMF and the detectors, we achieve mode-selective spatial filtering (MSSF) and optically reduce the cross talk. The robustness of the link is then increased when compared with an implementation without MSSF. This allows for a larger number of channels.

Cost optimization of optical in-building networks

We compare the CapEx and OpEx of in-building networks for fibre and Cat-5E solutions. For residential homes, our analysis shows that total network costs during economic lifetime are lowest for a point-to-point duplex POF topology.