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Lightwave Technology, Journal of

Issue 3 • Date June 1985

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Displaying Results 1 - 25 of 45
  • [Front cover and table of contents]

    Page(s): 0
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    Freely Available from IEEE
  • Guest editorial

    Page(s): 425
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    Freely Available from IEEE
  • 32-Mbit/s star configured optical local area network design and performance

    Page(s): 511 - 524
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    This paper describes the transmitter/receiver design and performance of a 32-Mb/s star configured optical local area network (SOLARnet) that uses a 100 × 100 port optical star coupler and CSMA/CD procedure. A new collision detection technique that monitors coding rule violation (CRV) is proposed. Following noise band calculation, the CRV characteristics of the receiver that are restricted by noise or signal collision are discussed, and the actual circuit design is presented. Use of the new technique enables detection of an optical collision signal that is 8 dB lower than the main signal in a field trial. Other results measured in the field trial are also described. View full abstract»

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  • 100-Mbit/s LED-p-i-n transmitter and receiver modules for high-speed local area networks

    Page(s): 560 - 564
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    100-Mbit/s fiber-optic transmitter and receiver modules using a 1.3-μm light-emitting diode (LED)-p-i-n combination are developed for computer-link applications. The use of a dc-balanced coding scheme is desirable in such applications from the viewpoint of improving the transient response of the system. A modified duobinary class-II coding scheme is applied as a transmission code. Four monolithic integrated circuits, that is, a preamplifier, an automatic-gain-controlled (AGC) amplifier, regenerator, and LED driver, are developed and confirmed to be useful for realizing highly reliable compact modules. These modules are tested using a standard graded-index fiber. An allowable span loss of 12.4 dB is achieved at an error rate of 10-12. The degradation due to the data pattern transients from 1/12 to 11/12 is negligibly small. Total power consumption of modules is a 1.4-W/module pair with a 5-V single power supply. View full abstract»

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  • A core-clad composition for crystallization-free fluoride fibers

    Page(s): 569 - 573
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    Core and clad compositions to realize crystallization-free fluoride fibers are proposed. From the scattering measurements of reheated glasses, it is shown that the projected scattering loss of the fluoride glass fiber with the selected core-clad composition is expected to be 0.0045 dB/km at 4 μm. View full abstract»

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  • Wide passband grating multiplexer for multimode fibers

    Page(s): 590 - 594
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    A grating multiplexer in Littrow-configuration is presented, whose passband width-normalized to channel spacing-is comparable with grating demultiplexers. As shown by calculation, a wide passband is attainable by very small input fiber spacing. Using a standard-(50/125 mum)-GI-fiber as transmission fiber, a 1-dB pass-band of 30 nm with a channel spacing of 46 nm is achieved in an 8- channel device. The insertion losses for each channel are in the range 1.4-2.5 dB for 8- or 10-channel devices. View full abstract»

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  • A p-i-n bipolar optical receiver for submarine system application

    Page(s): 608 - 611
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    A p-i-n photodiode bipolar optical receiver using a high beta polysilicon emitter transistor has been investigated. The receiver operates from a single 6-V supply, has a dynamic range in excess of 20 dB, and has been tested at bit rates up to 1 Gbit/s. At 280 Mbit/s and 1.3 μm the measured sensitivity was -35 dBm. View full abstract»

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  • A beam propagation method analysis of active and passive waveguide crossings

    Page(s): 635 - 642
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    A beam propagation method is employed to analyze the characteristics of crossed optical waveguides and related switches, based on such crossed waveguides. The complex coupling properties of passive crossings are highlighted and general design guidelines for passive devices as well as for switches are given. View full abstract»

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  • A functional approach to the Luneburg's integral for the planar Luneburg lenses design

    Page(s): 684 - 687
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    Close-form approximate expression for the Luneburg's integral is derived, which warrants an accuracy within1.5 times 10^{-6}in the index profile computation for lenses with focal distances exceeding twice the lens radius. Simple integral condition for the computation accuracy controlling is evaluated. View full abstract»

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  • A process for recovering germanium from effluents of optical fiber manufacturing

    Page(s): 699 - 705
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    Germania is the primary dopant used to control the refractive index profile in optical waveguides. However, its poor efficiency of incorporation and its high cost create a need for recovery. This paper describes a system to recover the unused germanium from the manufacturing effluents. Briefly, the process includes 1) a gas scrubber to incorporate the unreacted germanium into solution, 2) a recirculation system to increase the germanium concentration, 3) a reaction to form a germanium precipitate, and 4) a filtration step to isolate the germanium-containing solids. The process is capable of recovering greater than 95 percent of the unreacted germanium. View full abstract»

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  • [Back cover]

    Page(s): c4
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    Freely Available from IEEE
  • Protocols for fiber-optic local area networks

    Page(s): 426 - 431
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    This paper is concerned with the use of optical-fiber and optoelectronic technology for the implementation of local area networks. For the purposes of this paper, we define a local area network as an information transport system which provides connectivity amongst distributed communicating entities within a structure (room, building); within a campus or an office complex; or within a geographical area about the size of a United States local access and transport area (LATA). This paper focuses on the subject of network protocols; i.e., how do we implement the orderly sharing of network resources. View full abstract»

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  • Launching condition dependence of bandwidth in graded-index multimode fibers fabricated by MCVD or VAD method

    Page(s): 601 - 607
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    Baseband frequency response of a single or concatenated MCVD and VAD fibers measured by two representative launching conditions-equilibrium mode distribution (EMD) and overfill mode distribution (OMD)-is studied. From computations based on the WKB approximation method and from experiments, it is found that the OMD exciter on the average results in a greater 6-dB bandwidth than the EMD exciter for a single MCVD fiber, but is does a smaller bandwidth for a single VAD fiber. On the other hand, in concatenated fibers, the EMD exciter results in a greater bandwidth of about 10 percent in comparison with the OMD exciter. The concatenation factors for MCVD fiber and VAD fiber are different for EMD excitation, while they are nearly identical with each other for OMD excitation. View full abstract»

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  • Development of a medium-/small-scale local area optical fiber loop network

    Page(s): 532 - 536
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    This report describes the outline of an optical loop network which is the most suitable for a system consisting of about 200 terminals. Upon development of an optical local-area network (LAN) to be used within this range, the compact, low cost, and general purpose properties, as well as the reliability and expandability of the system should be considered first. Especially, determination of the transmission rate and selection of the microprocessor to be used are important items to realize the compact and low cost network as desired. There are two examples for such systems which are used actually now. One is the HLN-8140 Loop, which is suitable for small-sized systems. It is a packet switching loop network using the token-passing method with a transmission rate of 1 Mbit/s. Another example is the HLN-8380 Loop which can cover up to medium-sized systems. It is a circuit-switching loop network with a transmission rate of 10 Mbit/s, and it allows transparent communications to be made via telephones and facsimiles. View full abstract»

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  • Practicability of determining the modal power distribution by measured near and far fields

    Page(s): 652 - 661
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    Under certain assumptions the modal power distribution in optical multimode fibers can be derived from either the near- or the far-field. We measured both intensities and compared the calculated mode spectra. From these results, it becomes clear which assumptions are necessary and how to control them. The influence on the modal power distribution by leaky modes and some error sources such as the profile exponent, the fiber end quality, and misalignments are shown. View full abstract»

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  • Fiber-optic local area passive network using burst TDMA scheme

    Page(s): 502 - 510
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    A fiber-optic loop-configured passive network using burst TDMA scheme which features high reliability and efficient communication capability is presented. The basic analysis for the passive network design including the level diagram, dynamic range, and TDMA burst synchronization are discussed. It is calculated that about 20 stations can be installed if the output peak power of laser diode is +20 dBm and the connector pair loss of optical access coupler is 1 dB. Efficient data transmission of nearly 80 percent with a frame length of 1 ms can be obtained in the TDMA system for 20 stations. The station equipment designs concerning to the burst-mode optical transmission and the unique word detection are also described. An experimental system model with three stations using 51.2-Mbit/s bit rate is constructed, and the feasibility of this passive loop-configured network has been confirmed. View full abstract»

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  • Token-based protocols for high-speed optical-fiber networks

    Page(s): 449 - 466
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    The local network medium is a pair of unidirectional fiber-optic busses to which stations are connected via passive taps. For this configuration, we present several protocols which provide round-robin, bounded delay access to all stations, and are particularly suited for high-speed transmission. The common characteristic of the protocols is the use of the token as the synchronizing event to schedule transmission. The token may be explicit (as in U-Net) or implicit (as in Tokenless Net). It may be used all the time, or it may be used simply to resolve collisions (as, in Buzz-Net). The protocols are shown to be cost effective at very high (bandwidth)x(length) products that are the unique characteristic of high-speed single-mode fiber networks. Furthermore, they are robust to failures because of the passive interfaces and the totally distributed control. The implementation of these protocols on fiber-optic busses is also discussed in the paper. View full abstract»

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  • Optical serial highway for CAMAC system using high- performance optical bus adapters

    Page(s): 525 - 531
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    This paper describes the basic architecture of the optical (CAMAC) serial highway system first, and then the architecture of the newly developed byte serial U-port adapter for optical transmission (BUAO), which is a key component of the optical highway system, as well as the results of experiments conducted on the system. Finally, this paper describes the measurement system in Japan Atomic Energy Research Institute as an application of the system. View full abstract»

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  • Increased power injection in multimode optical-fiber buses through mode-selective coupling

    Page(s): 537 - 543
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    The number of stations that can be put on an optical-fiber data bus is usually limited by the total allowable attenuation between transmitter and receiver. A fundamental assumption in local-area network designs has been that a passive bus coupler must remove from the bus the same fraction of optical power that it injects from the local transmitter. This mandates very inefficient power injection to the bus and limits the total number of stations that can be put on the bus. By considering mode-selective passive optical couplers, I show that this limitation can be overcome in principle, and practically all the local power can be injected. Calculations indicate that this can lead to an increase in injected power of around 7 dB, and an almost doubling of the number of possible stations on the bus. View full abstract»

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  • The fibernet II ethernet-compatible fiber optic LAN

    Page(s): 496 - 501
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    Fibernet II is a fiber-optic local area network (LAN) having an active-star configuration. It is plug compatible with the 10- Mbit/s coaxial-cable Ethernet LAN at its transceiver cable interface. Ethernet requires the detection of packet collisions; this function is implemented in Fibernet II at the active star node. Collision presence is signaled to the host transceivers with a unique in-band optical signal. Fibernet II features improved electromagnetic immunity, absence of signal radiation from cables, freedom from ground-loop currents due to ground potential differences between remote sites, new network topology options, and a growth path to future broad-band services. This paper describes the Fibernet II experimental system as implemented at the Xerox Palo Alto Research Center. A space-time analysis is presented which confirms that Fibernet II can support a network diameter of over 4.0 km, in contrast to the coax Ethernet which is limited to 2.5 km. View full abstract»

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  • Radiation loss in dielectric waveguide Y-branch structures

    Page(s): 674 - 677
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    Volume current method is used to calculate the radiation loss of dielectric waveguide Y-branch structures. Radiation loss of a Y-branch in the power-dividing mode of operation is calculated accurately for the first time, obtaining proper zero loss in the limit of the zero branching angle. Radiation loss of a Y-branch with parallel output guides is calculated and compared to the loss of a three guide coupler-divider; the Y-branch has smaller loss. Simple analytical formulas are given for approximate loss calculation in these structures. View full abstract»

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  • Single-mode data buses for local area network applications

    Page(s): 472 - 478
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    An optimized fifteen-terminal tapped-tee data bus and a 9 × 9 star data bus were constructed using low-loss single-mode fiber fused-tapered 2 × 2 and 3 × 3 couplers. High-speed data transmission was demonstrated at 500 Mbit/s with a maximum throughput loss of 33 dB for the tapped tee system and mean throughput loss of 11 dB for the star system. System design parameters and experimental results are given in each case. View full abstract»

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  • Video transmission characteristics in WDM star networks

    Page(s): 490 - 495
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    In local area networks (LAN's), it is desirable to transmit not only digital data but also moving video signals. This paper proposes a system employing a wavelength-division multiplexed star network which is satisfactory for the transmission of video signals in addition to digital data, and reports the evaluation results of the video transmission characteristics of the system employing a 32 port-pair star coupler. Video transmission was realized by the pulsed analogue transmission scheme. Pulse frequency modulation (PFM) and pulsed frequency modulation (pulsed-FM) were studied, and it was found that the SNR fluctuation due to modal noise was less by the pulsed-FM than by the PFM. It was also found that the difference in the modal noise was due to the differences in the demodulation characteristics of PFM and pulsed-FM. A 32 port-pair passive star coupler was used and a maximum of a 5-km network was experimented. The results showed that a good video SNR was obtainable in the experimental star network using laser diodes. Thus the feasibility of the broad-band network, employing a multiport-pair passive star coupler by the wavelength division multiplexing scheme, was proven. View full abstract»

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  • Single and multimode fiber bandwidth measurements with single and multilongitudinal mode lasers operating at 0.8-, 1.3-, and 1.5-µm wavelength

    Page(s): 695 - 698
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    The bandwidth characteristics of single and multimode optical fibers have been investigated with single and multilongitudinal mode laser sources operating at 0.8, 1.3, and 1.5 μm. It is shown that single-mode fiber with a cutoff wavelength of 1.3 μm can support 1 Gb/s transmission over at least 7.5 km with a 0.8-μm laser source. View full abstract»

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  • High-speed drawing of optical fibers with pressurized coating

    Page(s): 669 - 673
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    To make progress in high-speed drawing of optical fibers, a pressurized coating method was developed on the basis of viscous flow behavior of the coating resin. In a pressurized die, when the shear rate at the fiber surface is minimized, the pressure which is affected by the resin viscosity reaches on optimum condition, resulting in the coating diameter being dependent only on fiber and die diameters. Coating tension is given as a function of pressure so that it is closely related to the optimum pressure through the viscosity. Based on these fundamentals, a 1200-m/min drawing speed was achieved, indicating a smooth and uniform coating with good concentricity. It is clarified that fiber transmission loss does not fundamentally change in relation to the speed. View full abstract»

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Aims & Scope

The Journal of Lightwave Technology contains articles on current research, applications and methods used in lightwave technology and fiber optics.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Peter J. Winzer
Alcatel-Lucent Bell Labs