Author
Christoph Caspar
Other affiliations: Fraunhofer Society
Bio: Christoph Caspar is an academic researcher from Heinrich Hertz Institute. The author has contributed to research in topics: Wavelength-division multiplexing & Single-mode optical fiber. The author has an hindex of 18, co-authored 53 publications receiving 1069 citations. Previous affiliations of Christoph Caspar include Fraunhofer Society.
Papers published on a yearly basis
Papers
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TL;DR: The practicability of using phase modulation in a 16 channel 10 Gbit/s system over 1600 km of standard SMF with simple dispersion compensation and the robustness in presence of ASK modulated channels has been shown for the first time.
Abstract: The practicability of using phase modulation in a 16 channel 10 Gbit/s system over 1600 km of standard SMF with simple dispersion compensation and the robustness in presence of ASK modulated channels has been shown for the first time.
156 citations
TL;DR: The theoretical background of MMF transmission is discussed and an overview on system characterization and existing standards are given and the challenges on reach, speed, and capacity-extension techniques for next generations ofMMF systems are discussed.
Abstract: High-speed transmission in multimode fibers (MMF) is becoming attractive for the realization of high-capacity transmission systems at low cost. This paper discusses the theoretical background of MMF transmission and gives an overview on system characterization and existing standards. The authors review latest achievements in component development for highest-speed MMF systems and discuss the challenges on reach, speed, and capacity-extension techniques for next generations of MMF systems.
138 citations
TL;DR: A novel method based on the evaluation of amplitude histograms generated by asynchronous sampling is found to detect signal degradations due to noise, crosstalk or pulse distortion with a high sensitivity.
Abstract: A novel method for performance monitoring of transparent optical systems, based on the evaluation of amplitude histograms generated by asynchronous sampling, is investigated experimentally. The method was found to detect signal degradations due to noise, crosstalk or pulse distortion with a high sensitivity.
127 citations
TL;DR: In this article, the authors report the manufacturing and measurement of a fiber micro-ring absorption resonator for λ = 1.55 μm with a biconical reduced fibre diameter down to 8.5 μm.
Abstract: We report the manufacturing and measurement of a fibre micro-ring absorption resonator for λ =1.55 μm with a biconical reduced fibre diameter down to 8.5 μm. The small ring diameter of 2 mm exhibits a large FSR of 30 GHz. From the optical frequency response a finesse of 4.7 and an insertion loss of l.2 dB were measured and the power coupling coefficient was calculated to be 0.28. To our knowledge, this is the smallest optical ring resonator reported so far.
68 citations
TL;DR: In this paper, a ten-channel coherent fiber-optic broadband transmission system with a tunable heterodyne receiver with a sensitivity of -46 dBm at a bit error rate of 10-9.
Abstract: A laboratory ten-channel coherent fibre-optic broadband transmission system is reported. The frequency-division-multiplexed optical carriers are separated by 6 GHz and are demultiplexed by a tunable heterodyne receiver having a sensitivity of -46 dBm at a bit error rate of 10-9. In this system a maximum number of 64 channels can be installed.
63 citations
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TL;DR: Recent progress in multiwavelength networks are reviewed, some of the limitations which affect the performance of such networks are discussed, and examples of several network and switch proposals based on these ideas are presented.
Abstract: The very broad bandwidth of low-loss optical transmission in a single-mode fiber and the recent improvements in single-frequency tunable lasers have stimulated significant advances in dense wavelength division multiplexed optical networks This technology, including wavelength-sensitive optical switching and routing elements and passive optical elements, has made it possible to consider the use of wavelength as another dimension, in addition to time and space, in network and switch design The independence of optical signals at different wavelengths makes this a natural choice for multiple-access networks, for applications which benefit from shared transmission media, and for networks in which very large throughputs are required Recent progress in multiwavelength networks are reviewed, some of the limitations which affect the performance of such networks are discussed, and examples of several network and switch proposals based on these ideas are presented Discussed also are critical technologies that are essential to progress in this field >
1,382 citations
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
TL;DR: In this article, a model for the shape of optical fiber tapers, formed by stretching a fiber in a heat source of varying length, is presented, and a complete practical procedure for the formation of fiber taper with any reasonable shape is thus presented.
Abstract: A model for the shape of optical fiber tapers, formed by stretching a fiber in a heat source of varying length, is presented. Simple assumptions avoid any need for the techniques of fluid mechanics. It is found that any decreasing shape of taper can be produced. The procedure for calculating the hot-zone length variation required to produce a given shape of taper is described, and is used to indicate how an optical adiabatic taper can be made. A traveling burner tapering system is capable of realizing the model's prediction, and a complete practical procedure for the formation of fiber tapers with any reasonable shape is thus presented. >
836 citations
TL;DR: The characteristics of lightwave technology that facilitate the design of wavelength-division-multiplexing (WDM) networks are reviewed, and it is explained how WDM local networks can be built based on the single-hop and multihop approaches.
Abstract: An overview of emerging all-optical networks is given. The characteristics and alternative architectures for single-hop systems are discussed. The characteristics of lightwave technology that facilitate the design of wavelength-division-multiplexing (WDM) networks are reviewed, and it is explained how WDM local networks can be built based on the single-hop and multihop approaches. Various categories of single-hop systems are discussed: experimental systems, systems based on no pretransmission coordination, and systems based on pretransmission coordination, which also require a separate control channel. A simple classification for single-hop systems is provided. >
666 citations
19 Feb 2004
TL;DR: In this paper, the role of OPM as an enabling technology for advances in high-speed and optically switched networks is examined, with the focus on fault management and QoS monitoring in the optical domain.
Abstract: Progress in optical networking has stimulated interest in optical performance monitoring (OPM), particularly regarding signal quality measures such as optical signal-to-noise ratio (SNR), Q-factor, and dispersion. These advanced monitoring methods have the potential to extend fault management and quality-of-service (QoS) monitoring into the optical domain. This paper reviews OPM applications and techniques, while examining the role of OPM as an enabling technology for advances in high-speed and optically switched networks.
480 citations