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Lightwave Technology, Journal of

Issue 5 • Date May 1988

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Displaying Results 1 - 15 of 15
  • Performance implications of mode partition fluctuations in nearly single longitudinal mode lasers

    Publication Year: 1988 , Page(s): 626 - 635
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB)  

    A statistical model of mode partition fluctuations is developed for semiconductor laser diodes with a single dominant lasing mode and one vestigial side mode. It is the basis of a rigorous analysis of the influence of partition fluctuations on the performance of digital lightwave transmission systems. A Gauss quadrature rule is used to evaluate the average probability of error in the presence of mode-partition-dependent shot noise, photodetector multiplication noise, circuit noise, and intersymbol interference. This methodology permits the determination of reliable performance estimates enabling the establishment of permissible degrees of mode partition fluctuations View full abstract»

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  • Factors affecting fiber-optic transmission quality

    Publication Year: 1988 , Page(s): 611 - 619
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (820 KB)  

    Important factors related to further improvement and extension of optical-fiber transmission system performance are discussed, focusing on repeater spacing, data rate, and optical frequency utility. Relevant progress in optical-fiber loss, semiconductor laser properties (such as output power, spectrum, and modulation speed), low-noise broad-band photodetectors, and optical-frequency multiplexers/demultiplexers are reviewed View full abstract»

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  • Input power limits of single-mode optical fibers due to stimulated Brillouin scattering in optical communication systems

    Publication Year: 1988 , Page(s): 710 - 719
    Cited by:  Papers (45)  |  Patents (15)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (804 KB)  

    Stimulated Brillouin scattering (SBS) limits the optical power that can be transmitted through a single-mode fiber in long-distance optical communication systems, the authors have investigated SBS gain and threshold characteristics with amplitude-shift-keying (ASK), frequency-shift-keying (FSK), and phase-shift-keying (PSK) modulated lights to estimate the input power limitation set by SBS. It was shown that maximum fiber-input powers or the SBS thresholds for fixed-pattern (1010 . . .) ASK, FSK, and PSK modulated lights are 2, 4, and 2.5 times higher, respectively, than the threshold for unmodulated light. Theoretical predictions were experimentally verified by SBS gain measurements with FSK and PSK modulated lights. The first direct observation of SBS with FSK modulated light pumping is also described View full abstract»

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  • Forward error correction in dispersion-limited lightwave systems

    Publication Year: 1988 , Page(s): 643 - 654
    Cited by:  Papers (30)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1048 KB)  

    A rate 0.964 forward error correcting (FEC) code is integrated into the low-speed tributaries of a 565-Mb/s lightwave system as an exploratory system design approach toward relaxing requirements on laser sources in dispersion-limited operation. By virtually removing error rate floors, regardless of their cause, FEC is shown to provide an increasing advantage in conditions of greater degradation and to be effective against mode partition noise (MPN), mode jumping, and reflection impairments.The experimental FEC code is implemented in a standard gate array. The FEC code is described and its performance is analyzed. A new system design strategy is suggested for low-cost gigabit lightwave systems using FEC View full abstract»

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  • New method analyzing eye patterns and its application to high-speed optical transmission system

    Publication Year: 1988 , Page(s): 678 - 685
    Cited by:  Papers (12)  |  Patents (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (720 KB)  

    An advanced method of analyzing eye patterns is proposed which plots the eye pattern as a function of the error rate. The method is applied to high-speed optical-transmission systems and its usefulness is confirmed. Degradation of eye opening due to noise and intersymbol interference is investigated quantitatively using the 10-10 BER eye. An automatic gain-control system is evaluated from a viewpoint of eye margin, and a gain control system having an improved eye margin performance is proposed. Low-probability abnormal phenomena, such as turn-on fluctuations and mode partitioning in directly modulated distributed feedback (DFB) lasers, are observed using this method View full abstract»

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  • Dynamic polarization fluctuation characteristics of optical fiber submarine cables under various environmental conditions

    Publication Year: 1988 , Page(s): 728 - 738
    Cited by:  Papers (8)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (892 KB)  

    Polarization fluctuation characteristics of optical-fiber submarine cable under 8000-m-deep sea environmental conditions, optical-fiber submarine cable coupling under periodic variable tension, and cable performance during and after installation, are presented. As a worst case, it is demonstrated that the maximum frequency spectrum of polarization fluctuation is less than 200 Hz under dynamic composite stress states. It is found that the polarization fluctuation of the optical-fiber submarine cable coupling changes linearly with periodic variable tensile forces. It is confirmed that the power spectrum of polarization fluctuations are less than 50~60 Hz, and the maximum power spectra are between 5 and 10 Hz during the cable installation within a maximum cable tension of 18 kN (1.8 tons) and the cable laying speed of 3.5 knots, respectively View full abstract»

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  • Chromatic dispersion limitations in coherent lightwave transmission systems

    Publication Year: 1988 , Page(s): 704 - 709
    Cited by:  Papers (149)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (452 KB)  

    Computer simulation is used to evaluate the chromatic dispersion limitations for both various coherent lightwave transmission systems and direct-detection on-off keying (OOK) systems. The results show that for a 2-dB dispersion penalty the maximum modulation rate ranges from 5 to 9 Gb/s for systems operating at 1.55 μm with 15 ps/km-nm of chromatic dispersion and 100 km of fiber. The effect is less severe for OOK systems and most severe in coherent detection systems. Simulation results are in agreement with a available experimental data View full abstract»

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  • The influence of directly modulated DFB LD sub-mode oscillation on long-span transmission system

    Publication Year: 1988 , Page(s): 636 - 642
    Cited by:  Papers (18)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (500 KB)  

    Error-rate floors have been observed in several long-span transmission experiments at 500 Mb/s, using 1.5-μm distributed-feedback laser diodes (DFB LDs) and 1.3-μm zero dispersion optical fibers. It is proposed that for the threshold gain difference between main and submode (for DFB LDs), Δα is a good parameter to specify the submode oscillation characteristics. It is experimentally and theoretically confirmed that the threshold gain difference Δα must be greater than 5-6 cm-1, to avoid the error rate floor at 500 Mb/s. It was also confirmed that λ/4 phase-shifted DFB LDs can easily satisfy this condition View full abstract»

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  • Analysis of sensitivity degradation caused by the flicker noise of GaAs-MESFETs in fiber-optic receivers

    Publication Year: 1988 , Page(s): 660 - 667
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (624 KB)  

    The total input noise current and sensitivity of the fiber-optic receiver was calculated. The flicker noise source was included by adopting a pertinent flicker noise model. Power penalties caused by the flicker noise were calculated for various fiber-optic receivers using the calculated noise current. It has been found that the flicker noise affects the sensitivity over the whole range of the bit rates, and that the total input capacitance is an important parameter affecting the power penalty which is serious in the case of a high-impedance-type p-i-n FET receiver. The optimum feedback resistance for practical p-i-n FET receiver design is also suggested View full abstract»

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  • Dispersion penalty for 1.3 μm lightwave systems with multimode semiconductor lasers

    Publication Year: 1988 , Page(s): 620 - 625
    Cited by:  Papers (23)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (472 KB)  

    The effect of fiber dispersion on the performance of lightwave systems is analyzed for the case where multimode semiconductor lasers operating near the zero-dispersion wavelength of the single-mode fiber are used as sources. Both the intersymbol interference and the mode-partition noise are considered in the discussion of dispersion-induced power penalties. The theory is in agreement with an experiment in which the bit error rate is measured for lasers at various bit rates. The tolerable limits on the deviation of the laser wavelength from the zero-dispersion wavelength are obtained for a 1.3-μm system operating at 1.7 Gb/s. Monte Carlo simulations are used to predict the effect of mode-partition noise on the performance of such high-speed lightwave communication systems View full abstract»

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  • Polarization fluctuation characteristics of a highly birefringent fiber system under forced vibration

    Publication Year: 1988 , Page(s): 720 - 727
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (620 KB)  

    Polarization characteristics in environmental disturbance are evaluated, in terms of the signal-to-noise ratio (SNR), which is defined as the ratio of a mean to a standard deviation of time-varying signals. The SNR is computer-simulated, assuming a Gaussian probability distribution for the random variables, i.e. birefringent axis, linear retardance, and polarization mode-coupling. These parameters are assumed to fluctuate owing to the force vibration of a loudspeaker. A comparison of the numerical results with the experimental SNR provides a direct connection between fluctuations of the state of polarization (SOP) and SNR of received signals modulated by polarization noise in highly birefringent fiber systems View full abstract»

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  • Evaluation of power penalties caused by feedback noise of distributed feedback laser diodes

    Publication Year: 1988 , Page(s): 655 - 659
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (428 KB)  

    Power penalties caused by optical feedback noise of distributed feedback laser diodes were evaluated experimentally and theoretically. It was found that power penalties could be suppressed when the beam-relative intensity noises were reduced to less than -135 dB/Hz at 2 Gb/s. This goal can be satisfied using a commercially available optical isolator that has more than 25-dB isolation in the lasar transmitter View full abstract»

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  • Baud rate response: characterizing modal dispersion for digital fiber optic systems

    Publication Year: 1988 , Page(s): 668 - 677
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (928 KB)  

    A method of characterizing modal dispersion in optical fibers, for baseband digital applications, is developed. Pulse distortion due to modal dispersion is simulated using modal transfer functions and pseudorandom pulsetrains. The extent of the distortion at given baud rates is identified with eye diagrams. Received optical power penalties are calculated from eye diagrams for a spectrum of baud rates, resulting in a penalty-versus-baud rate function called a baud rate response (BRR). Three useful parameters are derived from the BRR. The BRR magnitude parameter and shape parameter are used accurately to calculate a fiber's modal-dispersion power penalty for any given baud rate. The maximum baud-rate length product provides a mechanism for specifying modal dispersion quality along fibers View full abstract»

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  • Transmission quality and performance of ILL repeaters used in optical FSK communications

    Publication Year: 1988 , Page(s): 695 - 703
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (692 KB)  

    The use of injection-locked laser diodes as nonregenerative repeaters for optical frequency-shift keying (FSK) transmission systems is considered, with emphasis being placed on potential impairments which may limit performance. Nonlinear phase distortion associated with the amplification of FSK signals by injection-locked lasers (ILLs) is considered, as are the effects of intensity fluctuations on the locking bandwidth, the influence pf laser phase noise, ILL frequency stability requirements, and the number of repeaters that can be cascaded before loss of lock occurs. How these factors combine to influence overall system performance is also examined View full abstract»

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  • A consideration of factors affecting future coherent lightwave communication systems

    Publication Year: 1988 , Page(s): 686 - 694
    Cited by:  Papers (15)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (708 KB)  

    The performance limitations of coherent lightwave communication technologies are examined. Their practical device requirements, with emphasis on optical heterodyne/homodyne detection and optical frequency-division multiplexing (optical FDM) are also discussed 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