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Author

Lars Gruner-Nielsen

Other affiliations: Technical University of Denmark
Bio: Lars Gruner-Nielsen is an academic researcher from Alcatel-Lucent. The author has contributed to research in topics: Dispersion (optics) & Dispersion-shifted fiber. The author has an hindex of 26, co-authored 52 publications receiving 3793 citations. Previous affiliations of Lars Gruner-Nielsen include Technical University of Denmark.


Papers
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Journal ArticleDOI
TL;DR: The development of the first practical ('black-box') all-optical regenerator capable of removing both phase and amplitude noise from binary phase-encoded optical communications signals is reported.
Abstract: Fibre-optic communications systems have traditionally carried data using binary (on-off) encoding of the light amplitude. However, next-generation systems will use both the amplitude and phase of the optical carrier to achieve higher spectral efficiencies and thus higher overall data capacities(1,2). Although this approach requires highly complex transmitters and receivers, the increased capacity and many further practical benefits that accrue from a full knowledge of the amplitude and phase of the optical field(3) more than outweigh this additional hardware complexity and can greatly simplify optical network design. However, use of the complex optical field gives rise to a new dominant limitation to system performance-nonlinear phase noise(4,5). Developing a device to remove this noise is therefore of great technical importance. Here, we report the development of the first practical ('black-box') all-optical regenerator capable of removing both phase and amplitude noise from binary phase-encoded optical communications signals.

549 citations

Journal ArticleDOI
TL;DR: In this paper, an optical-fiber-based non-degenerate PSA link consisting of a phase-insensitive parametric copier followed by a PSA that provides broadband amplification, signal modulation format independence, and nearly 6dB link noise-figure (NF) improvement over conventional, erbium-doped fiber amplifier based links.
Abstract: Optical phase-sensitive amplifiers (PSAs) are known to be capable, in principle, of realizing noiseless amplification and improving the signal-to-noise-ratio of optical links by 3 dB compared to conventional, phase-insensitively amplified links. However, current state-of-the-art PSAs are still far from being practical, lacking e.g. significant noise performance improvement, broadband gain and modulation-format transparency. Here we demonstrate experimentally, for the first time, an optical-fiber-based non-degenerate PSA link consisting of a phase-insensitive parametric copier followed by a PSA that provides broadband amplification, signal modulation-format independence, and nearly 6-dB link noise-figure (NF) improvement over conventional, erbium-doped fiber amplifier based links. The PSA has a record-low 1.1-dB NF, and can be extended to work with multiple wavelength channels with modest system complexity. This concept can also be realized in other materials with third-order nonlinearities, and is useful in any attenuation-limited optical link.

419 citations

Journal ArticleDOI
TL;DR: In this article, a method for measuring the nonlinear refractive index of optical fibers with an error of less than 5% is demonstrated, based on measuring the phase shift experienced by a dual-frequency beat signal, permitting a simple, highly sensitive, accurate, repeatable, and easily automated measurement procedure and sampling.
Abstract: A method for measuring the nonlinear refractive index of optical fibers with an error of less than 5% is demonstrated. The technique is based on measuring the nonlinear phase shift experienced by a dual-frequency beat signal, permitting a simple, highly sensitive, accurate, repeatable, and easily automated measurement procedure and sampling. Measurements of the nonlinear coefficient in standard telecommunication, dispersion-shifted, and a number of dispersion-compensated fibers are presented.

279 citations

Journal ArticleDOI
TL;DR: In this article, the basic principles for use of dispersion compensating fibers (DCF) are reviewed, including definition of figure of merit and condition for dispersion slope compensation, and the main design features of a triple-cladding index profile design are examined theoretically and experimentally.

255 citations

Journal ArticleDOI
TL;DR: In this article, the properties and use of conventional single-mode dispersion-compensating fibers (DCFs) for discrete compensation including loss and nonlinear effects are discussed.
Abstract: This paper reviews properties and use of conventional single-mode dispersion-compensating fibers (DCFs). The quality of the dispersion compensation expressed as residual dispersion after compensation is treated. Properties of actual DCFs for discrete compensation including loss and nonlinear effects are discussed. Fiber design with special emphasis on design tradeoffs is considered. The Raman properties of DCFs and their use as a discrete Raman amplifier are also discussed. Finally, DCF for use in dispersion-managed cables (DMCs) is addressed, including optimum fiber design and comparison of different configurations.

202 citations


Cited by
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Journal ArticleDOI
TL;DR: In this paper, the authors summarized the simultaneous transmission of several independent spatial channels of light along optical fibres to expand the data-carrying capacity of optical communications, and showed that the results achieved in both multicore and multimode optical fibers are documented.
Abstract: This Review summarizes the simultaneous transmission of several independent spatial channels of light along optical fibres to expand the data-carrying capacity of optical communications. Recent results achieved in both multicore and multimode optical fibres are documented.

2,629 citations

Journal ArticleDOI
TL;DR: In this article, the capacity limit of fiber-optic communication systems (or fiber channels?) is estimated based on information theory and the relationship between the commonly used signal to noise ratio and the optical signal-to-noise ratio is discussed.
Abstract: We describe a method to estimate the capacity limit of fiber-optic communication systems (or ?fiber channels?) based on information theory. This paper is divided into two parts. Part 1 reviews fundamental concepts of digital communications and information theory. We treat digitization and modulation followed by information theory for channels both without and with memory. We provide explicit relationships between the commonly used signal-to-noise ratio and the optical signal-to-noise ratio. We further evaluate the performance of modulation constellations such as quadrature-amplitude modulation, combinations of amplitude-shift keying and phase-shift keying, exotic constellations, and concentric rings for an additive white Gaussian noise channel using coherent detection. Part 2 is devoted specifically to the "fiber channel.'' We review the physical phenomena present in transmission over optical fiber networks, including sources of noise, the need for optical filtering in optically-routed networks, and, most critically, the presence of fiber Kerr nonlinearity. We describe various transmission scenarios and impairment mitigation techniques, and define a fiber channel deemed to be the most relevant for communication over optically-routed networks. We proceed to evaluate a capacity limit estimate for this fiber channel using ring constellations. Several scenarios are considered, including uniform and optimized ring constellations, different fiber dispersion maps, and varying transmission distances. We further present evidences that point to the physical origin of the fiber capacity limitations and provide a comparison of recent record experiments with our capacity limit estimation.

2,135 citations

Journal ArticleDOI
14 Aug 2003-Nature
TL;DR: Semiconductor lasers for optical pumping and fast optical saturable absorbers, based on either semiconductor devices or the optical nonlinear Kerr effect, have dramatically improved these lasers and opened up new frontiers for applications with extremely short temporal resolution, extremely high peak optical intensities and extremely fast pulse repetition rates.
Abstract: Ultrafast lasers, which generate optical pulses in the picosecond and femtosecond range, have progressed over the past decade from complicated and specialized laboratory systems to compact, reliable instruments. Semiconductor lasers for optical pumping and fast optical saturable absorbers, based on either semiconductor devices or the optical nonlinear Kerr effect, have dramatically improved these lasers and opened up new frontiers for applications with extremely short temporal resolution (much smaller than 10 fs), extremely high peak optical intensities (greater than 10 TW/cm2) and extremely fast pulse repetition rates (greater than 100 GHz).

1,914 citations

Journal ArticleDOI
TL;DR: In this paper, the authors review recent progress in non-silicon CMOS-compatible platforms for nonlinear optics, with a focus on Si3N4 and Hydex®.
Abstract: Nonlinear photonic chips can generate and process signals all-optically with far superior performance to that possible electronically — particularly with respect to speed. Although silicon-on-insulator has been the leading platform for nonlinear optics, its high two-photon absorption at telecommunication wavelengths poses a fundamental limitation. We review recent progress in non-silicon CMOS-compatible platforms for nonlinear optics, with a focus on Si3N4 and Hydex®. These material systems have opened up many new capabilities such as on-chip optical frequency comb generation and ultrafast optical pulse generation and measurement. We highlight their potential future impact as well as the challenges to achieving practical solutions for many key applications. This article reviews recent progress in the use of silicon nitride and Hydex as non-silicon-based CMOS-compatible platforms for nonlinear optics. New capabilities such as on-chip optical frequency comb generation, ultrafast optical pulse generation and measurement using these materials, and their potential future impact and challenges are covered.

1,218 citations

Journal ArticleDOI
10 Jan 2005
TL;DR: Differential-phase-shift keying has recently been used to reach record distances in long-haul lightwave communication systems and theoretical as well as implementation aspects of DPSK are reviewed.
Abstract: Differential-phase-shift keying (DPSK) has recently been used to reach record distances in long-haul lightwave communication systems. This paper will review theoretical, as well as implementation, aspects of DPSK, and discuss experimental results.

949 citations