Scheduled System Maintenance:
On Monday, April 27th, IEEE Xplore will undergo scheduled maintenance from 1:00 PM - 3:00 PM ET (17:00 - 19:00 UTC). No interruption in service is anticipated.
By Topic

Lightwave Technology, Journal of

Issue 7 • Date Jul 2001

Filter Results

Displaying Results 1 - 17 of 17
  • Improvement of switching time in a thermocapillarity optical switch

    Publication Year: 2001 , Page(s): 1023 - 1027
    Cited by:  Papers (12)  |  Patents (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (108 KB)  

    The switching time of existing thermocapillarity optical switches is about two orders of magnitude larger than that of other optical switches, such as a thermooptics switch and a free-space switch using microelectromechanical system technology. This paper reports a thermocapillarity switch whose switching time is comparable to that of the thermooptics and free-space switches. The greatly improved switching time is achieved by lowering the absolute viscosity of the refractive-index matching liquid and improving the switch design View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optical and physical characterization of SiO2-x-Al thin-film polarizer on x-cut LiNbO3 substrate

    Publication Year: 2001 , Page(s): 1051 - 1056
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (136 KB)  

    For the purpose of a mechanical evaluation of a metal-cladding polarizer, a precise characterization of SiO2-x-Al thin-film succession fabricated on a LiNbO3 substrate was made as well as an experimental optimization of the SiO2-x-Al polarizer for the Ti:LiNbO3 waveguide. A 10-nm-thick SiO2-x was selected as the optimized underlay of a SiO2-x-Al polarizer for the Ti:LiNbO3 waveguide using a wavelength of λ=1.55 μm. Results of scratch testing show that the adhesive strength of SiO2-x-Al films was almost the same level as that of Ti-Au films on a thick SiO2 layer, commonly used for metallic underlay of Au-plated electrodes. From observing SiO2-x -Al film using a transmission electron microscope, it was confirmed that the 10-nm-thick SiO2-x underlay stratified well without serious thickness fluctuation View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Output power excursions in a cascade of EDFAs fed by multichannel burst-mode packet traffic: experimentation and modeling

    Publication Year: 2001 , Page(s): 933 - 940
    Cited by:  Papers (11)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (152 KB)  

    A serious problem facing wavelength-division multiplexed (WDM) networks with fiber amplifier cascades is transient cross-gain saturation or gain dynamics of fiber amplifiers. Attention has been focused primarily on circuit-switched scenarios. When the number of WDM channels transmitted through a circuit-switching network varies, channel addition/removal will tend to perturb signals at the surviving channels that share all or part of the route. Even more serious bit error rate deterioration can arise in WDM packet switched burst mode networks. In this paper, we present experimental and theoretical results demonstrating the effect of fast power transients in erbium-doped fiber amplifiers (EDFAs) on packetized traffic transmitted through a chain of five EDFAs. Traffic of a local-area network has been transmitted over three channels. The effect of EDFA cross-gain saturation due to the burstiness of the traffic has been observed in a continuous-wave monitoring channel. The stabilizing effect of gain clamping of the first EDFA in the cascade has been investigated. The experimental results are extended to eight-channel WDM system using a large signal numerical analysis View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Radiative optical isolator and circulator

    Publication Year: 2001 , Page(s): 1028 - 1035
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (188 KB) |  | HTML iconHTML  

    A novel radiative optical isolator and a circulator are discussed in this paper. It is numerically estimated that with λ=1.3 μm, 45-dB isolation ran be achieved with an isolator of 8 mm in length. For a 21.5-mm-long 4-port circulator, the achievable isolation is about 45 dB, with approximately 1-dB insertion loss View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A general and rigorous WDM receiver model targeting 10-40-Gb/s channel bit rates

    Publication Year: 2001 , Page(s): 966 - 976
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (204 KB)  

    We present a general and rigorously formulated dynamic receiver model aiming at 10-40-Gb/s wavelength division multiplexing (WDM) system design applications. A demultiplexing (DEMUX) characteristic with periodic transfer function has been treated in detail and it has been indicated how the model should be adjusted to take into consideration a general type of noise spectral density (NSD). The bit error ratio (BER) is evaluated accounting for the influence of non-Gaussian detected amplified spontaneous emission (ASE) noise, noise correlation between stochastic noise samples in the receiver, the gain and effective noise figure variation with wavelength of optical amplifiers, channel crosstalk, and intersymbol interference (ISI) effects caused by nonideal signal modulation, fiber dispersion, fiber nonlinearities, optical MUX, and DEMUX filtering and the impulse response of the electrical low-pass filter in the receiver. Also, the influence of shot and thermal noise is taken into account. Numerical results for the BER are presented considering a realistic 16-channel 10-Gb/s WDM system operating in the C-band using normal transmission fibers and including cascaded erbium-doped fiber amplifiers (EDFAs) with dispersion compensating fibers View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Diffusion of moisture through optical fiber coatings

    Publication Year: 2001 , Page(s): 988 - 993
    Cited by:  Papers (16)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (116 KB) |  | HTML iconHTML  

    The strength of polymer-coated fused silica optical fiber is dependent on the ambient moisture because of stress corrosion. The diffusion rate of water vapor through the polymer coating can be estimated by monitoring the strength as a function of time after suddenly changing the ambient humidity. Not only is this technique a new way of sensing humidity, but it also allows estimation of the time needed for the coated fiber to equilibrate with its environment. A comparison has been made between the diffusion coefficients measured in this way and by monitoring the weight of free-standing polymer films as a function of time. Fickian diffusion has been assumed and is justified by the good agreement between the experiment and theory. The diffusion of water vapor both into and out of various polymers was investigated View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • 200-nm-bandwidth fiber optical amplifier combining parametric and Raman gain

    Publication Year: 2001 , Page(s): 977 - 981
    Cited by:  Papers (47)  |  Patents (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (116 KB) |  | HTML iconHTML  

    Theory shows that the gain bandwidth of a one-pump fiber optical parametric amplifier (OPA) using highly nonlinear fiber (HNLF) could be more than 200 nm. Under these circumstances, the OPA gain would overlap the pump-induced Raman gain. We have studied the combined effects of OPA and Raman gain theoretically and experimentally. The experimental results demonstrate a 200-nm bandwidth from a single fiber-optical amplifier and also verify that the influence of the Raman effect is relatively small, as predicted by the theory View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Frequency response and modeling of resonant-cavity separate absorption, charge, and multiplication avalanche photodiodes

    Publication Year: 2001 , Page(s): 1010 - 1022
    Cited by:  Papers (10)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (368 KB) |  | HTML iconHTML  

    A theoretical model incorporating the mechanism of resonant absorption of the multiple reflected lightwaves is presented for the frequency response of resonant-cavity (RC) separate absorption, charge, and multiplication (SACM) avalanche photodiodes (APDs). The derived theoretical expressions are general and can be readily applied to many other RC and non-RC APDs. These analytical expressions also allow for fast computation of the frequency response and bandwidth characteristics. Combining this frequency response theory with expressions of multiplication gain and ionization coefficients, an efficient approach is proposed for modeling the general performance characteristics of RC APDs. The modeling approach is applied to an InGaAs-AlGaAs RC SACM APD. The computed results are demonstrated, and the results of -3 dB bandwidth are comparable to experimental work. The validity of the modeling parameters is also discussed. It is further found that the normalized frequency response is unaffected when the value of the absorption coefficient is changed, suggesting that the standing-wave effect within the RC structure may not influence the bandwidth characteristics View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An investigation of the pressure-to-acceleration responsivity ratio of fiber-optic mandrel hydrophones

    Publication Year: 2001 , Page(s): 994 - 1003
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB)  

    The acceleration responsivity of the fiber-optic air-backed mandrel hydrophone is studied. This responsivity may be a significant noise source in high vibration environments. The pressure-to-acceleration responsivity ratio is therefore a figure of merit for the hydrophone. It is shown that an ideal hydrophone with a sufficiently rigid support cylinder should not show any first-order acceleration responsivity. The dominant contribution to any first-order acceleration responsivity is the deformation of the support cylinder due to acceleration. The responses are evaluated both theoretically and experimentally. This treatment gives a set of guidelines which should be followed in order to maximize the pressure-to-acceleration responsivity ratio. It is also theoretically and experimentally demonstrated that the axial acceleration responsivity can be significantly reduced by symmetrical elicitation of the hydrophone View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A method for rebroadcasting signals in an optical backplane bus system

    Publication Year: 2001 , Page(s): 959 - 965
    Cited by:  Papers (2)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (156 KB)  

    A guided-wave optical backplane bus system intended for use in high-performance board-to-board interconnects is described. Its multiplexed polymeric holograms can implement optical signal broadcast between boards so that all boards share common optical channels. By introducing an active coupler to the doubly multiplexed hologram at the center board, signals received from any board can be rebroadcast to all other boards. We describe the design concepts for a centralized optical backplane and the resulting performance and assembly advantages over previously developed guided-wave and free-space optical backplane bus systems used for broadcasting signals. These advantages include equalized fan-out power, increased interconnect distance, and simpler fabrication View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • New phase modulation technique based on spatial soliton switching

    Publication Year: 2001 , Page(s): 1036 - 1050
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (372 KB)  

    A phase modulation technique able to increase the transmission capacity of an optical channel is presented. It is based on spatial soliton switching properties. The modulator device accepts as inputs two streams of amplitude modulated pulses and generates an output stream of phase modulated pulses whose phase values depends on the different input combinations, coding properly the input streams and increasing the transmission capacity of the optical channel that carries this information. The modulator device can be properly cascaded, generating a unique stream of pulses capable of carrying the information of a certain number of input channels. A proper demodulator device is also presented. It is capable of accepting as input a phase modulated stream of pulses, generating as outputs the original amplitude modulated pulse streams View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Simultaneous all-optical demultiplexing and regeneration based on self-phase and cross-phase modulation in a dispersion shifted fiber

    Publication Year: 2001 , Page(s): 941 - 949
    Cited by:  Papers (8)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (268 KB) |  | HTML iconHTML  

    Simultaneous demultiplexing and regeneration of 40-Gb/s optical time division multiplexed (OTDM) signal based on self-phase and cross-phase modulation in a dispersion shifted fiber is numerically and experimentally investigated. The optimal walkoff time between the control pulse and OTDM signal is obtained by numerical simulation. Our experiment also shows that it is an effective method for realizing simultaneous demultiplexing and regeneration when used in the middle of a system or in the receiver with a proper walkoff time View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Axial and radial fluorescence of dye-doped polymer fiber

    Publication Year: 2001 , Page(s): 982 - 987
    Cited by:  Papers (5)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (132 KB) |  | HTML iconHTML  

    Fluorescence spectra of perylene-doped polymer fiber were measured in both radial and axial directions, i.e., for leaky and guided beams, by exciting the fiber with a pulsed laser of 460-540-nm wavelength. Green (540-550 nm) and yellow (580 nm) peaks were observed in the radial fluorescence spectrum. Measuring fluorescence change at positions closer to the input end and progressing forward to the output end, we observed that green fluorescence decreased rapidly corresponding to an attenuation constant at incident laser wavelength. In contrast, yellow fluorescence decreased gradually, because it was induced by the absorption of green fluorescence, which attenuated more gradually than incident laser. Therefore, in axial output beams, green fluorescence was much weaker than yellow. As incident laser power increased, intensities of axial green fluorescence and radial fluorescence (both green and yellow) saturated to a certain level. In contrast, axial yellow fluorescence increased nonlinearly with increase in laser power. The output light intensity became strongest at a fiber length of 20-30 mm. These phenomena were analyzed theoretically taking self-absorption and stimulated emission by fluorescent dyes into consideration View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Interferometric interrogation of in-fiber Bragg grating sensors without mechanical path length scanning

    Publication Year: 2001 , Page(s): 1004 - 1009
    Cited by:  Papers (6)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (80 KB)  

    We report the interrogation of a fiber Bragg grating (FBG) using an interferometer with a tilted mirror such that the optical path difference is a function of position on an array detector. Absolute measurements of mean resonant wavelength from the phase of the analytic signal of the spatial interferogram are determined, and a technique based on using a reference laser to compensate for performance degrading effects otherwise associated with spatially scanned interferometers is introduced. These measurements are not critically dependent on the accurate location of zero phase position. We have applied the technique to the absolute measurement of temperature-induced shifts in the grating resonant wavelength. A resolution of 0.025 nm for a spatially scanned optical path delay of only 200 μm was achieved. The technique has the potential for higher resolutions and for multiplexing View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Remotely pumped optical distribution networks: a distributed amplifier model

    Publication Year: 2001 , Page(s): 926 - 932
    Cited by:  Patents (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (156 KB)  

    Optical distribution networks using remotely pumped erbium-doped fiber amplifiers (EDFAs) with a single pump source at the head end can conveniently provide signal gain without adding to the power-consumption cost and management complexity of having multiple locally pumped EDFAs in densely populated metropolitan areas. We introduce an analytical model for understanding the basic physical foundations of remotely pumped network design and for analyzing the number of users that can be supported using such a remote-pumping scheme View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A new architecture and a new metric for lightwave networks

    Publication Year: 2001 , Page(s): 913 - 925
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (308 KB)  

    The notion of a logically routed network was developed to overcome the bottlenecks encountered during the design of a large purely optical network. In the last few years, researchers have proposed the use of torus. Perfect shuffle, hypercube, de Bruijn graph, Kautz graph, and Cayley graph as an overlay structure on top of a purely optical network. All these networks have regular structures. Although regular structures have many virtues, it is often difficult in a realistic setting to meet these stringent structural requirements. In this paper, we propose generalized multimesh (GM), a semiregular structure, as an alternate to the proposed architectures. In terms of simplicity of interconnection and routing, this architecture is comparable to the torus network. However, the new architecture exhibits significantly superior topological properties to the torus. For example, whereas a two-dimensional (2-D) torus with N nodes has a diameter of Θ(N0.5), a generalized multimesh network with the same number of nodes and links has a diameter of Θ(N0.25). In this paper, we also introduce a new metric, flow number, that can be used to evaluate topologies for optical networks. For optical networks, a topology with a smaller flow number is preferable, as it is an indicator of the number of wavelengths necessary for full connectivity. We show that the flow numbers of a 2-D torus, a multimesh, and a de Bruijn network, are Θ(N1.5), Θ(N1.25), and Θ(N log N), respectively, where N is the number of nodes in the network. The advantage of the generalized multimesh over the de Bruijn network lies in the bet that, unlike the de Bruijn network, this network can be constructed for any number of nodes and is incrementally expandable View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • CDMA fiber-optic systems with optical hard limiters

    Publication Year: 2001 , Page(s): 950 - 958
    Cited by:  Papers (43)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (176 KB)  

    The code-division multiple-access (CDMA) technique has recently received substantial attention for fiber-optic communication systems. Simultaneous users are allowed to send their data asynchronously in CDMA fiber-optic systems through the assignment of unique “signature codes.” The multiple-access interference (MAI), which increases with the number of simultaneous users, severely limits the user capacity of the systems. An optical hard limiter can be placed at the front end of the desired receiver to reduce the effects of the MAI. We obtain the bit error probability for the CDMA fiber-optic systems with optical hard limiters. The exact performance analysis is performed and the result is a generalization of a previous analysis. For λc=1 codes, the result is not restricted to the case for threshold Th=w, yielding a more general and useful result than that obtained previously. The improvement in the performance from using a hard limiter with prime code and extended prime code is shown. The effect on the choice of decision threshold Th is also examined View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.

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