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Lightwave Technology, Journal of

Issue 12 • Date Dec 1993

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Displaying Results 1 - 25 of 43
  • Ge-laminated polarizer for 790-850-nm applications with extinction ratios larger than 50 dB and insertion losses below 0.4 dB

    Publication Year: 1993 , Page(s): 1978 - 1984
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (764 KB)  

    A laminated structure composed of alternating layers of Ge and SiO 2 (Ge-LAMIPOL) is usable as a miniaturized polarizer at 790-850 nm in fiber optic gyroscopes, for instance. However, peeling of the sputter deposited layers, due to the weak binding strength between Ge and SiO2, is a serious problem during the slicing process in preparation for assembly in the fiber. In order to improve the adhesive strength, the 1-nm-thick Si layers are inserted between Ge and SiO2 layers. The Si layer functions as the adhesive layer via the Si-O bonding formation in place of the weaker Ge-O bond. The new Ge-LAMIPOL, including 125 layers of (1-nm Si)/(4.5-nm Ge)/(1-nm Si)/ (800-nm SiO2) is successfully prepared without any fracture. The extinction ratio and the insertion loss were 51 and 0.33 dB at 850 nm, respectively, corresponding to 59.6 and 0.36 dB as the designed values View full abstract»

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  • Calculated fiber attenuation: a general method yielding stationary values

    Publication Year: 1993 , Page(s): 1900 - 1904
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (428 KB)  

    A method of calculating the attenuation constant of an optical fiber under very general but weakly guiding conditions is derived. The method, based on Galerkin's formalism, allows a nonuniform and complex refractive-index profile. The real and imaginary parts of the refractive index are allowed to vary independently and arbitrarily as a function of radius. The result is the predicted complex propagation constant. The results are inherently stationary View full abstract»

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  • Improved electrooptic efficiency in guided-wave modulators

    Publication Year: 1993 , Page(s): 2076 - 2079
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (316 KB)  

    The positioning of the waveguide in the electrode gap in Xc -cut, Yc-propagating LiNbO3 Mach-Zehnder intensity modulators with coplanar waveguide electrodes is analyzed, and experimentally investigated for the first time. It is found that for electrode gaps greater than 10 μm, the gap can be further increased with little increase in the drive voltage if the position of the waveguide is shifted toward the narrower center electrode. This is important because it allows the characteristic impedance of the modulator to be made closer to 50 Ω without incurring much of a drive voltage penalty View full abstract»

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  • Tunable liquid-crystal Fabry-Perot interferometer filter for wavelength-division multiplexing communication systems

    Publication Year: 1993 , Page(s): 2033 - 2043
    Cited by:  Papers (14)  |  Patents (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (988 KB)  

    We explain how to obtain the bandwidth and tunable range required for wavelength-division multiplexing communication systems and how to design tunable liquid-crystal Fabry-Perot interferometer filters. The main factors determining the performance are liquid-crystal loss, mirror loss, surface roughness, and parallelism, as well as mirror reflectivity and cavity gap. Experimental results closely agree with the designed performance. Temperature dependence, response time, acceptable input power, and reliability are investigated. Pigtailed polarization-independent filter modules with a Peltier controller are made and are shown to have low polarization dependence (<0.3 dB), low driving voltage (<15 V), and compact size, as well as a narrow bandwidth (0.3 nm), high finesse of 189, and large tunable range (50 nm) View full abstract»

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  • Speed and efficiency in multiple p-i-n photodetectors

    Publication Year: 1993 , Page(s): 2052 - 2056
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (464 KB)  

    We present a theoretical evaluation of the application of multiple intrinsic layers to enhancing the quantum efficiency of high-speed p-i-n photodetectors. It is shown that the use of multiple layers may lead to substantial improvements in the efficiency of detectors operating in the 20-100-GHz range, provided that the device area is reduced to limit the intrinsic capacitance and special care is taken to avoid large parasitic effects. Potential fabrication schemes are discussed View full abstract»

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  • A soliton ring network

    Publication Year: 1993 , Page(s): 2182 - 2190
    Cited by:  Papers (7)  |  Patents (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (888 KB)  

    The recent demonstration of ultrafast, cascadable, all-optical soliton gates, although with long latency and at an early stage of research, opens the possibility of niche exploitation in architectures whose performance is primarily limited by the absence of a few such logic elements. A candidate system is a widely distributed, self-routing short packet, slotted ring system running at peak rates well beyond that of the conventional electronic hosts at each access node. The authors describe an architecture for a system with a 1.25 GHz packet rate, 32-bit payload, and 100 Gb/s peak bit rate serving a few hundred user nodes. An optical format is retained by through-going node traffic, so that the overhead of conversion to/from electronics is incurred only at the source and destination. This design effort has served to sharpen their understanding of the strengths and weaknesses of using such gates in carefully chosen applications View full abstract»

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  • Long distance transmission through distributed erbium-doped fibers

    Publication Year: 1993 , Page(s): 2105 - 2115
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (936 KB)  

    High bit rate, all-optical long-distance transmission could be created through the combined use of loss-compensating gain in erbium-doped fibers and solitons. A detailed analysis of the distributed erbium-doped fiber, including the spectral-gain dependency, is combined with an optimum design of the transmission fiber and general bit-error-rate calculations. Changes in wavenumber, group velocity, and fiber dispersion due to erbium doping in a single-mode fiber are evaluated, and a reduction in bit-error rates due to the erbium spectral-gain profile is shown. Transmission through distributed erbium-doped fiber with 100-km separation between each pump-power station is shown, with a total bit-rate distance product of 55 Gb/s · Mm View full abstract»

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  • Design of a lossy tunable wavelength demultiplexer utilizing MgO:Ti:LiNbO3 depressed index waveguides

    Publication Year: 1993 , Page(s): 2080 - 2086
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (660 KB)  

    Design of an integrated optical tunable wavelength demultiplexer with a stable channel spacing is shown, utilizing software tools suitable for metal-clad diffused channel waveguides. The device, consisting on a three-mode depressed index waveguide with single-mode input and output waveguides has been designed using experimental data of double diffusion of MgO on Ti:LiNbO3 waveguides. The BPM simulations show the feasibility of the device, the stable spectral behavior and the narrow separation between channels obtained. It is also shown that the buffer layer between electrodes and waveguides can be eliminated depending on the design parameters View full abstract»

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  • Characteristics of S-shaped waveguide structures by the annealed proton exchange process in LiNbO3

    Publication Year: 1993 , Page(s): 2044 - 2051
    Cited by:  Papers (4)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (652 KB)  

    The loss of S-shaped waveguide bends in annealed proton-exchanged LiNbO3 integrated optical devices is found to be dependent on the length of thermal annealing time. The minimum transition length required in order to have losses as low as 0.2 dB is 2.0 mm for a 0.1-mm lateral offset. Intersecting waveguides based on S-shaped structures have been characterized for passive crossovers. An angle greater than 6° is required to provide a crosstalk of less than -30 dB. At a particular angle, intersecting waveguides offer the possibility of making a 3-dB coupler if an insertion loss of 1.2 dB is not a big concern. Zero-gap couplers based on S-shaped structures have been characterized for applications as 3-dB couplers as well. This type of 3-dB coupler has a much lower insertion loss of roughly 0.4-0.5 dB. Both 3-dB intersecting waveguides and 3-dB zero-gap couplers are less sensitive to wavelength variations View full abstract»

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  • Design of a multistripe array grating integrated cavity (MAGIC) laser

    Publication Year: 1993 , Page(s): 2191 - 2200
    Cited by:  Papers (7)  |  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (948 KB)  

    We consider the design of a multistripe array grating integrated cavity (MAGIC) laser based upon the Rowland circle solution for a circular grating. We discuss, in detail, the implementation of the MAGIC laser in the InP-based materials system for operation in the 1.5-μm fiber band. Particular attention is given to optical aberrations and their correction. The optical considerations presented are also valid for other materials systems. Suitable device parameters are derived for the case of a laser that emits eight wavelengths with a 4-nm spacing across the spectral band 1530-1560 nm. Such a device is ideally suited for use in wavelength division multiplexed (WDM) networks that employ erbium-doped fiber amplifiers View full abstract»

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  • Fiber four-wave mixing suppression using two incoherent polarized lights

    Publication Year: 1993 , Page(s): 2116 - 2122
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (512 KB)  

    A novel technique is proposed to reduce fiber fourwave mixing (FWM) in multichannel transmissions. Transmitters are constructed such that the light for one channel is composed of two incoherent orthogonal polarized lights. Theoretical treatment indicates that the FWM light power can be reduced by 3/8 and that the noise power due to the FWM light can be reduced by 3/16 by using the new technique. Results of preliminary experiments confirm the efficacy of the suppression mechanism View full abstract»

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  • Interfacial shearing stress in pull-out testing of dual-coated lightguide specimens

    Publication Year: 1993 , Page(s): 1905 - 1913
    Cited by:  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (520 KB)  

    A simple analytical model is developed for the evaluation of the interfacial shearing stress at the glass fiber surface in dual-coated optical fiber specimen subjected to tension. It is shown that the distribution of this stress is nonuniform and that, for the given specimen's length, its maximum value increases with a decrease in the thickness of the primary coating. The obtained results can be useful for comparing the adhesive strength of the primary coating material in fibers of different lengths and with different coating designs, as well as for the in situ evaluation of Young's (shear) modulus of this material from the measured axial displacement of the glass fiber View full abstract»

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  • Survivable optical fiber architecture employing ultra-wavelength-insensitive switch and coupler

    Publication Year: 1993 , Page(s): 2177 - 2181
    Cited by:  Papers (1)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (472 KB)  

    A new survivable fiber network architecture, active/passive routing architecture, is proposed and the main aspects of its performance are described. This architecture consists of an ultra-wavelength-insensitive switch as an active element and a wavelength-insensitive coupler as a passive element. The ultra-wavelength-insensitive switch is wavelength-independent from 1.25 to 1.6 μm. The survivable network was constructed by using the above routine elements and field-installed cables, and a switching experiment was carried out for WDM signals in the 1.3- and 1.55-μm bands. The bit-error-rate measurement proved that this fiber architecture can maintain high survivability for upstream and downstream signals by permitting a loss penalty of 0.5 dB. When a fiber fails, the signal is switched automatically to another fiber link, and signal synchronization was restored within 1 s View full abstract»

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  • A computer model of non-dispersion-limited stimulated Raman scattering in optical fiber multiple-channel communications

    Publication Year: 1993 , Page(s): 1914 - 1924
    Cited by:  Papers (12)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (800 KB)  

    The development of a computer model for non-dispersion-limited stimulated Raman scattering (SRS) in optical fiber multiple-channel communication systems is reported. The model takes into account the pump depletion due to SRS and the different attenuation coefficients at different wavelengths of operation. It can calculate the SRS effects in any fiber, provided the Raman gain profile for that fiber is known. Thus, the model is general in nature and can be used for a number of problems. It can be used to calculate the output power of all the channels, given the input of every channel and its operating wavelength. It can also be used, at least in principle, to determine the input power level if a desired level of output power is required. Moreover, it can be used to estimate the optical amplification of a signal due to SRS. This is possible because the governing equations for all of these processes are similar and therefore can be solved using the same approach View full abstract»

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  • Polarization properties of Rayleigh backscattering in single-mode fibers

    Publication Year: 1993 , Page(s): 1895 - 1899
    Cited by:  Papers (35)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (476 KB)  

    The state and degree of polarization (SOP, DOP) of Rayleigh backscattered light in low birefringent optical fibers was calculated using Stokes calculus. It was found that the SOP of Rayleigh backscattered light in low birefringent fiber is constant, viz. the same as the SOP of the incoming light. The DOP of Rayleigh backscattered light is one-third of the DOP of the incoming light, and not just anywhere between 0 and 100% as often mentioned in the literature. The experimental results agree with the calculations View full abstract»

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  • Grating-assisted nonlinear codirectional couplers

    Publication Year: 1993 , Page(s): 1990 - 1997
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (672 KB)  

    The advantages and flexibilities of using a grating to assist in the process of all-optical codirectional switching are investigated theoretically. It is found that the phase-matching condition which is required for complete switching is power dependent. In this respect, all-optical switching can be sensitive to a small change in input power level. In addition, this power-induced resonant tuning makes the grating structure automatically tuned, in the sense that complete switching becomes insensitive to manufacturing tolerances. The grating frequency is viewed as a “free design parameter,” which is selected to yield a desired device response. By chirping and/or scaling the grating frequency, the grating coupler can be designed to exhibit complete switching in the presence of material absorption and saturation View full abstract»

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  • Ultra-high-speed PLL-type clock recovery circuit based on all-optical gain modulation in traveling-wave laser diode amplifier

    Publication Year: 1993 , Page(s): 2123 - 2129
    Cited by:  Papers (23)  |  Patents (23)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (592 KB)  

    A new phase lock loop (PLL) is developed for very-high-speed optical timing extraction using traveling-wave laser-diode amplifier (TW-LDA) as a phase detector. The all-optical gain modulation of the TW-LDA is utilized to detect the relative phase difference between an optical signal and an optical clock The frequency response of the optical gain modulation measured with the optical heterodyne technique agrees with the theoretical results based on a rate equation model. With the developed PLL, 10-GHz optical timing clock is successfully extracted from randomly modulated optical signal pulses and the measured bit-error-rate performance shows no power penalty. Influence of the received optical noise on the phase variance of the PLL is also evaluated and it is concluded that 100 GHz operation is possible by increasing the input optical power to 10 mW View full abstract»

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  • Transmission of infrared laser radiation through silver-halide optical fibers during repeated plastic deformation

    Publication Year: 1993 , Page(s): 1889 - 1894
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (592 KB)  

    The infrared transmission of polycrystalline mixed silver-halide optical fibers was studied during repeated mechanical plastic bending of the fibers. Plastic bending is useful for various applications, and is not shown by other available types of fibers. The lifetime (number of cycles to failure) of the fibers was measured and characterized both optically and mechanically. Optical failure lifetime depends on composition, going through a maximum at around AgCl0.5Br0.5 composition, whereas the lifetime to mechanical fracture is not very sensitive to composition. The behavior and measured values are discussed in terms of the low-cycle fatigue phenomenon View full abstract»

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  • Design and performance of a multiple element slab waveguide spectrograph for multimode fiber-optic WDM systems

    Publication Year: 1993 , Page(s): 2009 - 2014
    Cited by:  Papers (5)  |  Patents (32)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (620 KB)  

    A new type of compact (<7 cm2) multiple element slab waveguide spectrograph suitable for medium resolution fiber-optic wavelength division multiplexing (WDM) applications in the 700 nm to 900 nm optical band is described. The spectrograph consists of a replicated diffraction grating formed on the convex edge of a multilayer glass-ceramic slab waveguide stack The grating design, based on an aberration corrected derivative of the classic Rowland spectrometer, was first verified holographically, and then implemented by replication from a ruled master grating. A combination of thick-film solder glass glazing, lamination, optical finishing and grating replication was chosen to produce a multiple element spectrograph that enables accurate spectral referencing, and can be interfaced by a passive optical fiber array and detector array alignment procedures View full abstract»

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  • Optical fiber loop memory using vertical to surface transmission electro-photonic device

    Publication Year: 1993 , Page(s): 2140 - 2144
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (364 KB)  

    An optical fiber loop memory is proposed, using a photonic switch device of a vertical to surface transmission electro-photonic device. The photonic switch works as an optical pulse repeater. The operation stability as the memory was analyzed, and more than 30 minutes storage time has been realized. The maximum operational clock was as high as 20 MHz. This memory may be a part of the future optical computer View full abstract»

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  • Compared merits of hard/soft decoding for coherent optical communications impaired by phase noise

    Publication Year: 1993 , Page(s): 2093 - 2099
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (548 KB)  

    Phase noise of semiconductor lasers severely degrades the performance of coherent optical fiber communication systems, imposing restrictions on the admissible laser linewidth. The application of a forward error controlling (FEC) scheme is a suitable means to combat the bit-error-rate (BER) degradation due to phase noise and to relax the laser linewidth requirement. In this paper, a heterodyne coherent binary phase-shift keying (BPSK) system and a heterodyne differential phase-shift keying (DPSK) system, both with a Viterbi decoded convolutional coding scheme, are investigated to illustrate the improvements of the system performance. In particular, for the first time, the use of soft decision decoding in such systems is analyzed and its advantage over hard decision decoding is demonstrated View full abstract»

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  • Bit-error-rate characterization of IM-DD ultralong-distance optical communication systems with Er-doped fiber amplifiers using a recirculating loop

    Publication Year: 1993 , Page(s): 2100 - 2104
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (460 KB)  

    The authors have evaluated the bit error-rate characteristics of the IM-DD ultralong-distance optical communication systems employing Er doped fiber amplifiers. A 2.5- and 5-Gb/s IM-DD nonreturn-to-zero signal was analyzed by recirculating-loop experiments. They used a fiber loop of four Er-doped fiber amplifiers and three spans of dispersion-shifted single-mode fibers for the experiments. A 16,000-km transmission at 2.5 Gb/s and an 11,000-km transmission at 5 Gb/s were successfully achieved. The allowable wavelength-tunable range of the optical transmitter for the 9000-km transmission was also measured at the bit rate of 5 Gb/s. The experimental results show the possibilities and limitations of transoceanic optical communication systems using Er-doped fiber amplifier repeaters View full abstract»

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  • Stable single-mode erbium fiber-grating laser for digital communication

    Publication Year: 1993 , Page(s): 2021 - 2025
    Cited by:  Papers (25)  |  Patents (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB)  

    In this paper we report the fabrication of a short, robust, single-mode Er3+ fiber-grating laser. This laser is proven by the successful outcome of a long-term bit-error-rate test at the 10-15 level in a 5- G/s fiber transmission experiment. In the process we present a new pumping geometry, the elucidation of one origin of relaxation oscillations that have plagued previous lasers and the demonstration of a simple electronic feedback scheme for suppressing them. This prototype source shows real promise for use in a high-speed communications system View full abstract»

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  • A photonic integrated-optic RF phase shifter for phased array antenna beam-forming applications

    Publication Year: 1993 , Page(s): 2201 - 2205
    Cited by:  Papers (35)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (348 KB)  

    A photonic in-phase/quadrature (I-Q) RF phase shifter utilizing two integrated optic Mach-Zehnder modulators has been tested. This phase shifter demonstrates the capability of 360° phase control, <1° RF errors at constant amplitude, and <1° errors over a 30-dB RF amplitude taper View full abstract»

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  • Polarization analysis of LP01 and LP11 intermodal interference in highly birefringent bow-tie optical fibers

    Publication Year: 1993 , Page(s): 1925 - 1936
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (912 KB)  

    A polarization analysis of bimodal highly birefringent fibers in which LP01, LP11, interference takes place is performed. The polarization state of the interference pattern is theoretically described in terms of recently proposed spatial Stokes parameters on the basis of coupled-mode equations and Jones matrix formalism. The general quasimonochromatic case is considered and depolarization as well as interference fading are accounted for. Special attention is paid to application of the results to fiber-optic sensors, and the basic schemes for the detection of the interference beat signal are discussed. The theoretical conclusions are supported by experiments in which the modal polarization and intermodal interferometric response to elongation of a bow-tie bimodal fiber is investigated. Measurements are carried out on both a separate fiber and on a multifiber assembly at various input conditions 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