By Topic

Lightwave Technology, Journal of

Issue 5 • Date March1, 2014

Filter Results

Displaying Results 1 - 25 of 34
  • Front Cover

    Publication Year: 2014 , Page(s): C1
    Save to Project icon | Request Permissions | PDF file iconPDF (243 KB)  
    Freely Available from IEEE
  • Journal of Lightwave Technology publication information

    Publication Year: 2014 , Page(s): C2
    Save to Project icon | Request Permissions | PDF file iconPDF (141 KB)  
    Freely Available from IEEE
  • Table of contents

    Publication Year: 2014 , Page(s): 873 - 874
    Save to Project icon | Request Permissions | PDF file iconPDF (100 KB)  
    Freely Available from IEEE
  • Application of Expurgated PPM to Indoor Visible Light Communications—Part I: Single-User Systems

    Publication Year: 2014 , Page(s): 875 - 882
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (639 KB) |  | HTML iconHTML  

    Visible light communications (VLC) in indoor environments suffer from the limited bandwidth of LEDs as well as from the inter-symbol interference (ISI) imposed by multipath. In this work, transmission schemes to improve the performance of indoor optical wireless communication (OWC) systems are introduced. Expurgated pulse-position modulation (EPPM) is proposed for this application since it can provide a wide range of peak to average power ratios (PAPR) needed for dimming of the indoor illumination. A correlation decoder used at the receiver is shown to be optimal for indoor VLC systems, which are shot noise and background-light limited. Interleaving applied on EPPM in order to decrease the ISI effect in dispersive VLC channels can significantly decrease the error probability. The proposed interleaving technique makes EPPM a better modulation option compared to PPM for VLC systems or any other dispersive OWC system. An overlapped EPPM pulse technique is proposed to increase the transmission rate when bandwidth-limited white LEDs are used as sources. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Application of Expurgated PPM to Indoor Visible Light Communications—Part II: Access Networks

    Publication Year: 2014 , Page(s): 883 - 890
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (741 KB) |  | HTML iconHTML  

    Providing network access for multiple users in a visible light communication (VLC) system that utilizes white light emitting diodes (LED) as sources requires new networking techniques adapted to the lighting features. In this paper we introduce two multiple access techniques using expurgated PPM (EPPM) that can be implemented using LEDs and support lighting features such as dimming. Multilevel symbols are used to provide M-ary signaling for multiple users using multilevel EPPM. In the first technique, the M-ary data of each user is first encoded using an optical orthogonal code assigned to the user, and the result is fed into a EPPM encoder to generate a multilevel signal. The second multiple access method uses subsets of the EPPM constellation to apply MEPPM to the data of each user. While the first approach has a larger Hamming distance between the symbols of each user, the latter can provide higher bit-rates for users in VLC systems using bandwidth-limited LEDs. Both techniques are able to support up to 15 simultaneous users transmitting 200 Mb/s with a bit error rate of 10-3 under normal lighting conditions. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Novel Sensor Design Using Photonic Crystal Fibres for Monitoring the Onset of Corrosion in Reinforced Concrete Structures

    Publication Year: 2014 , Page(s): 891 - 896
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2010 KB) |  | HTML iconHTML  

    In this paper, a novel sensing technique has been designed and investigated for the direct, in situ detection of steel corrosion distributed in reinforced concrete structures. At present, structural health monitoring in reinforced concrete structures is generally focused on monitoring the corrosion risk of the reinforcing steel. It is of significant importance, however, to inform industry of both the onset of corrosion and the corrosion rate as these are key contributors to structural degradation and thus evaluating the service life of the structures. This paper aims to address the above challenges by describing a novel corrosion sensor design using birefringent photonic crystal fibres. The technique exploits fully both the birefringence of the fibres for force/pressure measurement and their very low temperature sensitivity to detect the onset of corrosion. This new type of sensor not only determines the onset of corrosion but also allows for better monitoring along the length of a reinforcement bar. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Photonic Integrated Filter With Widely Tunable Bandwidth

    Publication Year: 2014 , Page(s): 897 - 907
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (10316 KB) |  | HTML iconHTML  

    We present a comprehensive design, fabrication, and characterization analysis of compact silicon-on-insulator bandpass filters with widely tunable bandwidth. The filter architecture is based on an unbalanced Mach-Zehnder interferometer loaded with a pair of ring resonators. A wide bandwidth tunability (from 10% to 90% FSR) can be achieved by controlling the resonant frequency of the rings while preserving a good filter off-band rejection. Design rules are provided that take into account fabrication tolerances as well as losses. Furthermore, the use of tunable couplers allows a more flexible shaping of the spectral response of the filter. The sensitivity with respect to nonlinear effects is carefully investigated. Operation over a wavelength spectrum of 20 nm is demonstrated, making the device suitable for channel subset selection in WDM systems, reconfigurable filters for gridless networking and adaptive filtering of signals. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Maximum Likelihood Sequence Detection for Mitigating Nonlinear Effects

    Publication Year: 2014 , Page(s): 908 - 916
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (993 KB) |  | HTML iconHTML  

    Coherent detection allows for a more effective compensation of transmission impairments in the electrical domain. However, in order to be effective, a detection strategy should be based on an accurate channel model capable of providing sufficiently accurate signal statistics. While in the linear regime such a model is available and linear impairments such as chromatic dispersion and polarization-mode dispersion can be almost fully compensated by adaptive equalizers, this is not the case for nonlinear impairments, whose mitigation is essentially based on heuristic strategies. One of the most considered strategies is the back-propagation (BP) technique, based on channel inversion. It is shown that BP is most effective only in dispersion-unmanaged links, while a low-complexity Viterbi detector with proper metrics can achieve better results in the case of dispersion-managed links. It is also shown that, in the cases where it is effective, BP is far from approaching optimal performance. Indeed, proper processing after BP can significantly increase performance. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Optical Pump Induced Thermal Sensitivity Reduction in a Minimized Er/Yb-Codoped-Fiber Mach–Zehnder Interferometer

    Publication Year: 2014 , Page(s): 917 - 921
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (377 KB) |  | HTML iconHTML  

    The intensity and wavelength dependent thermal characteristics of a minimized Er/Yb-codoped-fiber Mach-Zehnder interferometer are demonstrated theoretically and experimentally. It can be used as a high sensitivity temperature sensor if no pump is introduced. However, once a pump is launched into the interferometer, its thermal sensitivity is reduced. Under pump power of 59.4 mW, 3.1 pm/°C and 10.3 pm/°C reductions of its thermal sensitivities are achieved for the resonance dips at short and longer wavelength ranges, respectively. This suggests that its thermal sensitivity can be tuned by introducing into a pump, and its thermal stability can be improved with the pump. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analysis of the Effect of Vignetting on MIMO Optical Wireless Systems Using Spatial OFDM

    Publication Year: 2014 , Page(s): 922 - 929
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (772 KB) |  | HTML iconHTML  

    The performance of pixelated multiple-input mul-tiple-output optical wireless communication systems can be impaired by vignetting, which is the gradual fall-off in illumination at the edges of a received image. This paper investigates the effect of vignetting for a pixelated system using spatial orthogonal frequency division multiplexing (OFDM). Our analysis shows that vignetting causes attenuation and intercarrier interference (ICI) in the spatial frequency domain. MATLAB simulations indicate that for a given constellation size, spatial asymmetrically clipped optical OFDM (SACO-OFDM) is more robust to vignetting than spatial dc biased optical OFDM (SDCO-OFDM). Moreover, for the case of SDCO-OFDM, the very large zeroth subcarrier causes severe ICI in its neighbourhood causing flattening of the bit error rate (BER) curves. We show that this BER floor can be eliminated by leaving some of the lower spatial frequency subcarriers unused. The BER performance can also be improved by applying a vignetting estimation and equalization scheme. Finally, it is shown that equalized SACO-OFDM with 16-QAM has the same overall data rate as equalized SDCO-OFDM using 4-QAM, but requires less optical power. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Hierarchical Optical Network-On-Chip Using Central-Controlled Subnet and Wavelength Assignment

    Publication Year: 2014 , Page(s): 930 - 938
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1038 KB) |  | HTML iconHTML  

    Optical network-on-chip (ONoC) is a promising alternative to be served as the fundamental architecture for future many-core system. However, several problems of ONoC, such as power consumption, arbitration overhead, and device cost, pose many limitations to the architecture design. In this paper, a novel hierarchical ONoC structure named CWNoC is proposed, which is a 256-core architecture composed of multiple central-controlled subnets. It reduces the network complexity by dividing the whole network into several subnets and lowers the arbitration overhead by adopting centralized arbitration logic in each subnet. An efficient wavelength assignment method, making full use of broadband microring resonators, is also employed in CWNoC, which facilitates simplifying the optical layer and reducing the possibility of contention. The simulation results show that CWNoC has a better latency and power consumption performance. For example, when low and medium load is applied, the latency reduction can be as much as 40 ns compared with WANoC, while the total power consumption is reduced by 70%. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Engineering an Extended Gain Bandwidth Hybrid Raman—Optical Parametric Amplifier for Next Generation CWDM PON

    Publication Year: 2014 , Page(s): 939 - 946
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (610 KB) |  | HTML iconHTML  

    We describe a model and present simulation results for the optimization of an extended amplification bandwidth hybrid Raman-Optical Parametric amplifier (HROPA) in Tandem configuration. In this configuration, the Raman and Parametric processes are separated and each one takes place in a separate span of fiber, allowing for optimization of amplification gain (e.g., > 20 dB), gain bandwidth (e.g., 170 nm) and gain ripple (e.g., <; 4 dB). We also focus on the potential signal degradation performance due to the generation of idlers within the operational bandwidth. To overcome this limitation, we propose and model a modified HROPA design, which allows for the management and the suppression of idlers in the amplifier. The idler suppression is achieved through partitioning the channels in two sub-bands and using a wavelength-division multiplexed DEMUM/MUX pair to limit/suppress the idlers, as well as crosstalk terms generated in the amplifier. Our study shows that with proper selection of pump wavelength and power and engineering the HROPA with correct filter transfer function, we can achieve error free performance even in the case when significant misalignment of the transmitter wavelength from the center of the coarse WDM channel band exists. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Simple and Accurate Method to Analyze Lossy Optical Waveguides: Applications to Surface Plasmon Resonance Based Devices

    Publication Year: 2014 , Page(s): 947 - 951
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (508 KB) |  | HTML iconHTML  

    We present a simple and accurate method for obtaining modal characteristics of highly lossy waveguides. The method requires locating the positions of Lorentzian peaks for both real and imaginary parts of the propagation constants. As compared to the method calculating half width at half maximum (HWHM) of Lorentzian peaks, the present method gives much more accurate results and works even in the cases where the former fails. The method is simple to implement and converges very fast. The applicability of the method is demonstrated by taking examples of surface plasmon resonance based planar waveguide structures. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Design of Silica Encapsulated High-Q Photonic Crystal Nanobeam Cavity

    Publication Year: 2014 , Page(s): 952 - 958
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (583 KB) |  | HTML iconHTML  

    We report on the design of photonic crystal nanobeam cavity fully encapsulated in silica. The proposed design, based on the principle of gentle confinement of the electromagnetic field, is mostly analytical and emphasizes on the most realistic options for fabricating nanocavities, in particular in III-V semiconductor materials. After determining the field decay inside the photonic bandgap of a nanobeam photonic crystal, we engineer the envelope of the cavity mode into a Gaussian shape by shifting only progressively the lattice constant. We discuss the various implementations of such shifts and give a simple algorithm to position each hole. The resonant wavelengths are found to depend linearly on the central lattice constant and on the radius of the holes. High Q factors above 10 6 and modal volume V close to ( λ/n) 3 are obtained. In particular, Q factors remain high for a wide range of values of the central lattice constant and of holes radii, hence showing exceptional tunability properties as well as robustness with respect to common fabrication defects. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Modeling of Effective Host Mobility for the Simulation of Polymeric Host-Guest Light Emitting Diodes

    Publication Year: 2014 , Page(s): 959 - 965
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (397 KB) |  | HTML iconHTML  

    Organic host-guest structures with a disordered polymer as the host material have various applications in the field of organic light emitting diodes such as polymeric phosphorescent LEDs or polymeric fluorescent white LEDs. Effective mobility is a crucial parameter in the simulation of such host-guest OLEDs with conventional drift-diffusion method. In the present paper, the master equation approach is applied to calculate the effective host mobility in a host-guest structure and investigate the effect of energy disorder, guest density, charge carrier density and electric field on this parameter. By employing a parameterization scheme, an accurate model for the effective host mobility is also derived that can be employed for more precise and realistic simulation of OLEDs incorporating a host-guest layer with polymeric host. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • High-Speed Silicon Mach–Zehnder Optical Modulator With Large Optical Bandwidth

    Publication Year: 2014 , Page(s): 966 - 970
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (664 KB) |  | HTML iconHTML  

    We report a carrier-depletion silicon Mach-Zehnder optical modulator with large optical bandwidth by adopting two symmetric arms. The fiber-to-fiber loss of the device is about 7.2-8 dB in the wavelength range from 1525 to 1565 nm. We have used the truncation method to accurately measure the loss of the optical splitter and combiner, and the on-chip loss is about 3.8 dB. The dynamic extinction ratios at the speed of 40 Gb/s are 4.9-6.4 dB in the wavelength range from 1529 to 1565 nm. By analyzing the dependence of the optical bandwidth on the optical path difference between the two arms, we find that there is an unexpected optical path difference of around 3.3 μm between the two arms, which is considered to originate from the nonuniform morphologies of the waveguide and the nonuniform doping profiles along the two arms and is responsible for the slight wavelength dependence of the static and dynamic response of the silicon Mach-Zehnder optical modulator. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Closed-Loop Interrogation Technique for Multi-Point Temperature Measurement Using Fiber Bragg Gratings

    Publication Year: 2014 , Page(s): 971 - 977
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1706 KB) |  | HTML iconHTML  

    In this paper a closed-loop interrogation technique for multi-point temperature measurement using fiber Bragg gratings (FBG) is presented. The technique uses a broadband light source and n tunable FBGs to interrogate an array of n FBGs sensors placed along the optical fiber. Each center wavelength of the tunable FBGs is matched with the center wavelength of one FBG sensor placed in the array. The light source directly illuminates the sensor array, so that all the light reflected from the FBGs enters in the optical circuit through an optical circulator and the reflected spectrum of each sensing FBG illuminates a matched tunable FBG. Because the current generated by the photodiode is proportional to the convolution between the two FBGs profiles (the sensor FBG and the tunable FBG), by controlling the value of the convolution at a fixed value, the center wavelengths of the two FBGs are kept spaced by a constant value. Therefore, the temperature of the FBG sensor can be associated with the temperature of the tunable FBG. A two channel prototype was constructed to validate the technique and a very high resolution of ±0.001 °C was obtained. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Analytical Prediction of the Main Oscillation Power and Spurious Levels in Optoelectronic Oscillators

    Publication Year: 2014 , Page(s): 978 - 985
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1078 KB) |  | HTML iconHTML  

    We use a nonlinear analytic approach to predict the main oscillation mode power and spurious levels in ultrapure microwave optoelectronic oscillators (OEOs). This approach takes into account N simultaneously mode falling inside the RF filter bandwidth and calculates all the dominant InterModulation Products (IMPs) that fall in the fundamental zone. We show that nonlinear microwave photonic links exhibit the capture effect. By considering this effect, we derive analytical expressions that govern the behavior of the OEOs in the steady state. We find that when the small-signal open-loop gain is increased beyond a critical value, OEOs start a multimode operation from which the spurious levels grow rapidly. Our analytical predictions are verified by numerical simulations and experimental data. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Microstructured Tube-Leaky Glass Waveguide for Delivery of High-Powered Er:Yag Laser

    Publication Year: 2014 , Page(s): 986 - 990
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (558 KB) |  | HTML iconHTML  

    We present tube-leaky fiber with microstructured glass supports as a hollow core microstructured optical fiber. Attenuation constants of tube-leaky fibers are derived by using a ray optic method and designed the wall thickness of the fibers for Er:YAG laser which is often used for medical applications. From the loss measurements of Er:YAG laser, the tube-leaky fibers supported by microstructured glass made of borosilicate-glass can deliver laser with 0.85 dB/m despite of high material absorption around laser wavelength. The high power energy transmission results of the fabricated fibers are at the order of 80-120 mJ. These energies are enough to ablate biological tissues in surgical operations. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Hybrid Optoelectronic Networks-on-Chip Architecture

    Publication Year: 2014 , Page(s): 991 - 998
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (7028 KB) |  | HTML iconHTML  

    Optical/Photonic networks-on-chip (NoC) have been considered as a promising and viable paradigm to interconnect a large number of processing cores at chip level. Hybrid optoelectronic NoCs provide a more practical solution by using the electronic network for local communication while the optical network for global communication. This paper explores how to efficiently combine optical and electronic networks to build a hybrid NoC. A butterfly fat tree-based hybrid optoelectronic NoC architecture is proposed using the generic wavelength-routed optical router. Simulation results demonstrate that, compared with electronic mesh- and CMesh-based NoCs, the proposed hybrid NoC achieves the best power efficiency with comparable throughput and significantly reduces the latency under localized traffic. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • A Study of the Linearity Performance of a Stimulated Brillouin Scattering-Based Microwave Photonic Bandpass Filter

    Publication Year: 2014 , Page(s): 999 - 1005
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (384 KB) |  | HTML iconHTML  

    The linearity of stimulated Brillouin scattering (SBS) is studied in detail for the first time. A closed-form expression which measures the linearity of an SBS system is derived. This expression allows one to design the region of linear operation, and the amount of Brillouin gain of an SBS system, by altering some basic system parameters. The theory presented is experimentally verified using an SBS-based microwave photonic filter structure. The effect of the length of the Brillouin medium on the linearity of the filter is investigated, and a 9.7 dB extension in the dynamic range is demonstrated by reducing the length of the fibre used as the Brillouin medium, from 25 to 0.57 km, while the filter stopband rejection level remains 30 dB. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • An Analysis on the Optimization of Closed-Loop Detection Method for Optical Voltage Sensor Based on Pockels Effect

    Publication Year: 2014 , Page(s): 1006 - 1013
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (608 KB) |  | HTML iconHTML  

    In engineering practice, the closed-loop optical voltage sensor (OVS) based on Pockels effect cannot reach the required precision level mainly due to the various disturbance and noise of system, so the application of OVS for low voltage measurement is restricted. Considering the cross coupling of the main and second closed-loops, the model of disturbance and noise of system that adopts the four-state modulation method is analyzed in the main closed-loop of OVS. Based on the established noise-perturbed stochastic model of OVS, we design a closed-loop detection algorithm for the OVS system to guarantee the mean-square exponential stability with a prescribed H performance in order to optimize the detection precision of OVS. The experimental results show that the detection precision of OVS is 0.144 V while the relative measurement error of the scale factor is within ± 0.15% in measuring low AC voltages from 140 to 500 V, which verifies the effectiveness of the proposed detection scheme. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Dynamic and Adaptive Bandwidth Defragmentation in Spectrum-Sliced Elastic Optical Networks With Time-Varying Traffic

    Publication Year: 2014 , Page(s): 1014 - 1023
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1810 KB) |  | HTML iconHTML  

    Elastic optical networks (EONs) enable network operators to have agile bandwidth management in the optical layer. In this paper, we investigate dynamic and adaptive bandwidth defragmentation (DF) in EONs with time-varying traffic using connection reconfigurations. We consider how to design DF procedure in a systematic way, and study the problems that have not been fully explored so far. Basically, we divide the procedure design into four subproblems: “How to reconfigure?,” “ How to migrate traffic?,” “When to reconfigure?,” and “What to reconfigure?,” and solve them sequentially. For “How to reconfigure?,” we investigate the combination of routing and spectrum assignment (RSA) algorithms for DF, i.e., the RSA algorithm that the connections are originally served with and the algorithm that they are re-optimized with. For “ How to migrate traffic?,” we propose to construct a dependency graph to represent the relations among the selected connections and to use it to assist the best-effort traffic migration. A move-to-vacancy method is also proposed to further reduce the traffic disruptions. For “When to reconfigure?” and “ What to reconfigure?,” we propose intelligent timing selection and adaptive DF ratio selection methods to tackle the tradeoff between the bandwidth blocking probability (BBP) performance and operational complexity. Simulation results show that the algorithm with both methods implemented (DF-AT-AR) achieves better tradeoff between BBP performance and operational complexity, when compared with existing algorithms. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Realistic Photonic Filter Design Based on Allpass Substructures With Waveguide Loss Compensation

    Publication Year: 2014 , Page(s): 1024 - 1031
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (579 KB) |  | HTML iconHTML  

    We present a lowpass design algorithm targeted specifically for photonic implementation. Allpass filter based systems are ideal for photonic realizations because they can be naturally realized using a variety of nanoscale dielectric components. The allpass filters based lowpass system is a particularly noteworthy example of advanced usages of allpass sub-structures. While the structure is excellent for implementation using photonic components, practical considerations about its suboptimal performance are yet to be considered. Realistic optical filters are subject to the imperfections of photonic materials and limitations from current fabrication capability. The waveguide power loss is an unavoidable source of performance degradation that arises when realizing photonic filters. In this paper, we consider the derivation of allpass filters based lowpass structures that can minimize the loss effect. The proposed algorithm will enable the utilization of low cost photonic devices for stringent design requirements, and also improve the performance of high end photonic devices. View full abstract»

    Full text access may be available. Click article title to sign in or learn about subscription options.
  • Fiber Optic Line-Based Sensor Employing Time Delay Estimation for Disturbance Detection and Location

    Publication Year: 2014 , Page(s): 1032 - 1037
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (634 KB) |  | HTML iconHTML  

    A line-based fiber optic sensor employing time delay estimation to locate time-varying disturbance is proposed. The sensor consists of two line-based interferometers, multiplexed with a broadband light source, interfering unit and sensing fiber by wavelength division multiplexer, and hence detected signals with different wavelengths generated by the same disturbance are obtained. After a unique data processing algorithm, two signals with fixed time delay are achieved and the time delay is determined by the position of the disturbance. By the signal correlation method to extract the time delay, the position of the disturbance can be measured. The performance of the sensor is examined and compared with the conventional sensor, based on the null frequency of the spectrum of the phase difference generated by the disturbance, through an experimental setup with the total length of sensing fiber up to 70 km. Experimental results show that the sensor is advantageous for easy installation, low location error and flexibility, especially in long-distance perimeter security application. 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