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Communications Magazine, IEEE

Issue 10 • Date Oct. 1989

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Displaying Results 1 - 6 of 6
  • High-capacity lightwave local are networks

    Page(s): 20 - 26
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (751 KB)  

    The author presents an overview of fundamental considerations that guide and motivate research in this area. He explores the relationship between the bandwidth of the fiber, the available power and the loss in various network designs, and the throughput of networks as limited by the medium-access techniques and control mechanisms. He discusses two approaches to opening up the bottleneck that seem particularly promising. The first, multihop, uses a novel network architecture to achieve high capacity with existing devices; the second, wavelength division multiple access (WDMA), emphasizes new devices in a relatively conventional architecture. Noting that the primary disadvantage of the bus topology, poor energy efficiency, could be overcome with a suitable optical amplifier to compensate for the high signal attenuation in the network, the author discusses one of the most promising candidates, the traveling-wave semiconductor amplifier. He also discusses medium-access considerations.<> View full abstract»

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  • Multiwavelength networks and new approaches to packet switching

    Page(s): 27 - 35
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    The author shows how the bandwidth available through the use of multiwavelength optical-fiber technology can be used to achieve novel large-capacity switching systems to address anticipated switching bottlenecks. He does so by describing the features and network applications of a specific multiwavelength network, the Bellcore LAMBDANET packet switch. The discussion is then extended to a number of recent proposals for switching fabrics based on this new multiwavelength technology. The particular technologies he discusses are: the photonic knockout switch, a proposal similar to the concept of the LAMBDANET, but not requiring N receivers at each node; the FOX (fast optical cross-connect), an active wavelength routing approach; the ShuffleNet architecture; the HYPASS and BHYPASS switches; the coherent wavelength division lambda switch; and the Bellcore Star-Track multicast switch.<> View full abstract»

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  • Optical heterodyne communications systems

    Page(s): 36 - 41
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (735 KB)  

    The potential of heterodyne systems is examined, beginning with a description of a typical optical heterodyne detection system. Sources for coherent systems are reviewed, and frequency agility is discussed. The problem of optical frequency determination and control is addressed. Two approaches for achieving polarization diversity reception are considered. Progress toward applying the techniques described is assessed.<> View full abstract»

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  • Wavelength-tunable and single-frequency semiconductor lasers for photonic communications networks

    Page(s): 42 - 52
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    The present status of wavelength-tunable and single-frequency devices needed for the broadband integrated services digital network (BISDN) of the future is reviewed. The various systems applications and requirements and, in turn, the device parameters that are relevant to those requirements are described. The basic material and structural parameters of the lasers are discussed, and the fundamental operational principles are explained. Various single-frequency, high-speed, and tunable laser structures are reviewed, and their characteristics are presented.<> View full abstract»

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  • Wavelength-tunable optical filters: applications and technologies

    Page(s): 53 - 63
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    The authors review noncoherent, frequency-tunable filter (receiver) technologies. They describe three basic mechanisms of wavelength filtering: filters that are based on the wavelength dependence of interferometric phenomena, with emphasis on Fabry-Perot interferometer filters; filters that are based on the wavelength dependence of coupling between optical fields (modes) induced by external perturbations (both acoustooptic and electrooptic filters are described); and filters that are based on resonant amplification of optical signals in semiconductor laser diode devices (these devices provide gain in addition to wavelength selectivity). For each technology the authors explain briefly the principles of operation and quantify the relevant system parameters: tuning range, channel separation, number of channels, crosstalk isolation, gain and distortion, speed of wavelength tuning, and complexity. They present a unified picture of filtering mechanisms in an appendix.<> View full abstract»

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  • Fiber-based local access network architectures

    Page(s): 64 - 73
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    The attributes of the various architectural alternatives are discussed. Several systems proposed for the delivery of telephone service and/or distributive video services in the local access network are described. The status of the standardization of interfaces for the broadband integrated services digital network (BISDN) based on the synchronous optical network (SONET) and asynchronous transfer mode (ATM) is examined.<> View full abstract»

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IEEE Communications Magazine covers all areas of communications such as lightwave telecommunications, high-speed data communications, personal communications systems (PCS), ISDN, and more.

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Sean Moore
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