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Lightwave Technology, Journal of

Issue 21 • Date Nov.1, 2012

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Displaying Results 1 - 25 of 27
  • Front Cover

    Page(s): C1
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  • Journal of Lightwave Technology publication information

    Page(s): C2
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  • Table of contents

    Page(s): 3297 - 3298
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  • Generation and Transmission of 10-Gbaud Optical 3/4-RZ-DQPSK Signals Using a Chirp-Managed DBR Laser

    Page(s): 3299 - 3305
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1219 KB) |  | HTML iconHTML  

    We have demonstrated the generation and transmission of 10-Gbaud optical 3/4-return-to-zero differential quadrature phase-shift-keying (3/4-RZ-DQPSK) signals using a chirp-managed distributed-Bragg-reflector (DBR) laser (CML), without requiring any differential encoder or external modulator. We realized error-free transmission in 60-km standard single-mode fiber without any dispersion compensation. No optical signal-to-noise ratio penalty was induced. We also investigated the impact of different optical spectrum reshaper filters in CML on the transmission performance. The tolerance against the amplitude fluctuation of the electrical driving signal was also studied. View full abstract»

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  • A Robust and Tunable Add–Drop Filter Using Whispering Gallery Mode Microtoroid Resonator

    Page(s): 3306 - 3315
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1235 KB) |  | HTML iconHTML  

    We fabricated and theoretically investigated an add-drop filter (ADF) using an on-chip whispering gallery mode (WGM) microtoroid resonator with ultrahigh-quality factor (Q) side coupled to two taper fibers, forming the bus and drop waveguides. The new device design incorporates silica side walls close to the microresonators which not only enable placing the coupling fibers on the same plane with respect to the microtoroid resonator but also provides mechanical stability, leading to an ADF with high drop efficiency and improved robustness to environmental perturbations. We show that this new device can be thermally tuned to drop desired wavelengths from the bus without significantly affecting the drop efficiency, which is around 57%. View full abstract»

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  • FirstLight: Pluggable Optical Interconnect Technologies for Polymeric Electro-Optical Printed Circuit Boards in Data Centers

    Page(s): 3316 - 3329
    Save to Project icon | Click to expandQuick Abstract | PDF file iconPDF (1519 KB) |  | HTML iconHTML  

    The protocol data rate governing data storage devices will increase to over 12 Gb/s by 2013 thereby imposing unmanageable cost and performance burdens on future digital data storage systems. The resulting performance bottleneck can be substantially reduced by conveying high-speed data optically instead of electronically. A novel active pluggable 82.5 Gb/s aggregate bit rate optical connector technology, the design and fabrication of a compact electro-optical printed circuit board to meet exacting specifications, and a method for low cost, high precision, passive optical assembly are presented. A demonstration platform was constructed to assess the viability of embedded electro-optical midplane technology in such systems including the first ever demonstration of a pluggable active optical waveguide printed circuit board connector. High-speed optical data transfer at 10.3125 Gb/s was demonstrated through a complex polymer waveguide interconnect layer embedded into a 262 mm × 240 mm × 4.3 mm electro-optical midplane. Bit error rates of less than 10-12 and optical losses as low as 6 dB were demonstrated through nine multimode polymer wave guides with an aggregate data bandwidth of 92.8125 Gb/s. View full abstract»

    Open Access
  • Refractive Index Profile in Special Structure of Optical-Damage-Resistant Mg-Diffused Near-Stoichiometric Ti:Mg:LiNbO _{3} Waveguide

    Page(s): 3330 - 3337
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1405 KB) |  | HTML iconHTML  

    Refractive index in special optical-damage-resistant MgO-diffused near-stoichiometric (NS) Ti:LiNbO3 (Ti:LN) waveguide structure that a number of single-mode strip waveguides are embedded in a planar waveguide is profiled on the basis of the measured mode field profile of strip waveguide. In the NS strip waveguide, the Ti4+-induced extraordinary index increase studied follows a sum of two error functions in the width direction and a sum of two Gaussian functions in the depth direction. In the NS planar waveguide, the index increase follows a Gaussian function. On the basis of the established index profile model, the mode field profiles were calculated using variational method and compared with the measured data. The results show that the calculated mode sizes are in good agreement with the measured. In addition, the profile characteristics of Ti4+-concentration in both the strip and planar waveguides were analyzed by secondary ion mass spectrometry and are correlated with the refractive index increase. The result shows that the profile characteristics of the index increase and Ti4+-concentration are similar for both the strip and planar waveguides and there exists a linear relationship with a slope of ~ 2.0×10- 3(mol%)-1. View full abstract»

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  • A Dual Golay Complementary Pair of Sequences for Improving the Performance of Phase-Shift Pulse BOTDA Fiber Sensor

    Page(s): 3338 - 3356
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (3939 KB) |  | HTML iconHTML  

    We propose in this paper to configure a dual Golay complementary pair of sequences (DGCP) by nesting one Golay complementary pair of sequences (GCP) into the other GCP. We show that the DGCP also has the unique property that the side lobes of the correlation functions are cancelled exactly as the conventional GCP. The DGCP allows the simultaneous use of coded RZ-pulses and coded NRZ-pulses in the pump light of the Brillouin optical time-domain analysis (BOTDA). We call them in this paper coded discrete pulses and coded continuous pulses, respectively. The simultaneous use of both types of coded pulses for the BOTDA makes it possible to employ virtually longer code than the use of only one kind of coded pulses. We theoretically show the dependence of signal-to-noise ratio enhancement (SNRE) on the code length of the DGCP as well as on the code lengths of the GCPs used for the discrete and continuous pulses. Examination of the spatial resolution is also given. Experimental results illustrate the theoretical considerations; about 7 dB of SNRE and 10-cm of spatial resolution are achieved by using DGCP, being in accordance with the theory. View full abstract»

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  • Throughput and Efficiency of EPON Registration Protocol

    Page(s): 3357 - 3366
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1786 KB) |  | HTML iconHTML  

    In this paper, we study the performances of the registration protocol in Ethernet passive optical networks (EPONs). In each registration process, the newly-connected optical network units (ONUs) send their requests to the optical line terminal (OLT) without any scheduling, which may cause collisions and lower the registration success probability. Thus, a random-delay based registration protocol has been defined in the IEEE 802.3av standard to prevent collisions. Intuitively, the registration protocol of EPON possesses similar characteristics as medium access control (MAC) protocols. Based on this principle, we derive the closed-form expression of the registration throughput to evaluate the random-delay based protocol. We show that an optimal discovery-window size can be determined by maximizing the registration efficiency. Our analytical results indicate that the random delay introduced in the protocol is helpful to enhance the registration efficiency when the number of ONUs is large, or if all ONUs are clustered. However, the throughput improvement by random delay is marginal if there is only a small number of evenly distributed ONUs in the vicinity of EPON. View full abstract»

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  • Luminescence Study of Polymer Optical Fibers Doped With Conjugated Polymers

    Page(s): 3367 - 3375
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2284 KB) |  | HTML iconHTML  

    The characterization of the spectral emission and of the photostability of polymer optical fibers (POFs) doped with conjugated polymers has been carried out taking into account the distribution of the dopant in the fiber core. Four different conjugated polymers embedded in the matrix of the typical POF material have been analyzed. Measurements include, among others, evolutions of the emission with excitation wavelength and time, spectral changes for different excitation irradiances, and the influence of the propagation distance along the fiber. View full abstract»

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  • A Model for Calculating the Bidirectional Scattering Properties of Phosphor Layer in White Light-Emitting Diodes

    Page(s): 3376 - 3380
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (944 KB) |  | HTML iconHTML  

    In this study, a model for calculating the bidirectional scattering properties of phosphor layer was established by considering the light absorption and light conversion of phosphor particle simultaneously. Based on the present model, the light extraction efficiency was calculated and validated by comparing with the existing experimental data and models. It is demonstrated that the present model predicts better. The transmission and reflection intensities of blue light and yellow light were found to be the functions of phosphor thickness. There exists a close critical phosphor thickness for reflected blue light and transmitted yellow light. The critical phosphor thickness is relative to the phosphor concentration. View full abstract»

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  • Highly Birefringent Elliptical-Hole Microstructure Fibers With Low Confinement Loss

    Page(s): 3381 - 3386
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (724 KB) |  | HTML iconHTML  

    A novel kind of elliptical-hole highly birefringent microstructure optical fibers (MOFs) with two defects and six rings is analyzed and proposed. Simulation results show that geometrical birefringence of this elliptical-hole MOF is two times higher than that of the circular-hole ones, which found to be about 3.5×10-3. The polarization beat length of such fiber is calculated to be 0.44 mm. Besides, this kind of MOF with two defects can couple with single mode fibers efficiently and the confinement loss is almost near zero when the cladding ring number reaches 6. Such proposed fiber with high birefringence and low confinement loss can find really potential applications in the fields of light transmission and optical sensing. View full abstract»

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  • Ultrafast All-Optical Half Adder Using Quantum-Dot Semiconductor Optical Amplifier-Based Mach-Zehnder Interferometer

    Page(s): 3387 - 3393
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (826 KB) |  | HTML iconHTML  

    Interferometric devices have drawn a great interest in all-optical signal processing for their high-speed photonic activity. Quantum-dot semiconductor optical amplifier (QD-SOA)-based gate has added a new momentum in this field to perform all-optical logic and algebraic operations. In this paper, a new and alternative scheme for all-optical half adder using two QD-SOA-based Mach-Zehnder interferometers is theoretically investigated and demonstrated. The proposed scheme is driven by the pair of input data streams for one switch between which the Boolean xor function is to be executed to produce sum-bit. Then the output of the first switch and one of the input data are utilized to drive the second switch to produce carry-bit. The impact of the peak data power as well as of the QD-SOAs current density, small signal gain, and QD-SOAs length on the ER and Q-factor of the switching outcome are explored and assessed by means of numerical simulation. The operation of the system is demonstrated with 160 Gbit/s. View full abstract»

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  • Three-Dimensional Finite-Element Solutions for Crossing Slot-Waveguides With Finite Core-Height

    Page(s): 3394 - 3400
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1123 KB) |  | HTML iconHTML  

    A three-dimensional vectorial finite element method (3-D-VFEM) for waveguide discontinuity problems is newly formulated and implemented. Through the use of the 3-D-VFEM, transmission characteristics of two types of crossing slot-waveguides with finite core-height are investigated for the first time. One is a direct crossing and the other is a crossing filling up the slots locally. Results show that three-dimensional analysis considering the finite core-height is indispensable. View full abstract»

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  • Ultra-Compact High-Speed Electro-Optic Switch Utilizing Hybrid Metal-Silicon Waveguides

    Page(s): 3401 - 3406
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (590 KB) |  | HTML iconHTML  

    Hybrid Metal-Silicon waveguides are a novel novel form of waveguide with wide ranging applications in photonics. This paper describes the basic properties of such waveguides, discusses the behavior of hybrid waveguide directional couplers and presents a design for an ultra-compact electro-optic switch based on these properties. At 1 V drive voltage, switching at speeds up to 30 Gbits/sec can be achieved in a device that is 30 μm long. View full abstract»

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  • Photonic Crystal Fiber With Two Infiltrated Air Holes for Temperature Sensing With Excellent Temporal Stability

    Page(s): 3407 - 3412
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1133 KB) |  | HTML iconHTML  

    A photonic crystal fiber sensor is created by infiltrating liquid with higher refractive index than background silica into two adjacent air holes situated in different layers. When the refractive index of the liquid is decreased to that of silica by heating, the two liquid rods and the solid core form a three-parallel-waveguide structure, which enables efficient mode energy coupling between the two eigenmodes and results in an interference fringe pattern. Theoretical analysis has been carried out to reveal the modes involved in the interference. Moreover, the temporal stability of the device is enhanced by inserting short sections of ultraviolet curable glue at both ends of the liquid, followed by solidification, to prevent the liquid-air interface fluctuation. The temperature sensitivity achieved is ~ -8.8 nm/°C, in the range between 45 and 50°C. View full abstract»

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  • Performance of Graphene Mediated Saturable Absorber on Stable Mode-Locked Fiber Lasers Employing Different Nano-Dispersants

    Page(s): 3413 - 3419
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    High-performance stable mode-locked fiber lasers (MLFLs) employing nano-composite polymer-graphene saturable absorber (SA) are demonstrated. The graphene layers were dispersed by two different dispersants including fluorinated MICA clay (MICA) and poly(oxyethylene)-segmented imide (POEM). Using the SA made by graphene dispersed in MICA with thickness and concentration product (TCP) of 36 (μ m*wt%), the MLFLs exhibited pulsewidth, 3-dB spectral bandwidth, and modulation depth (MD) of 393±14 fs, 6.6 nm, and 2.57%, respectively. By contrast, the graphene dispersed in POEM provides a TCP of 38 (μm*wt%) to make the MLFLs deliver pulsewidth, 3-dB spectral bandwidth, and MD of 442±32 fs, 5.9 nm, and 1.70%, respectively. In comparison, the graphene SA dispersed by MICA performs a better MLFL pulse quality and uniformity than that dispersed by POEM. Both MLFLs with SAs fabricated by graphene/MICA and graphene/POEM reveal shortened pulsewidth and enhanced MD as the TCP increases. This observation indicates that the TCP and MD serve as key parameters for characterizing the MLFL pulsewidth. In this study, the nano-MICA dispersant is used for the first time to fabricate the graphene-polymer based SA film and has demonstrated highly stable and uniform ML pulse laser output. Judicious selection of dispersants for dispersing graphene in a homogeneous state is essential for enhancing the MLFL performance. This stable and uniform mode-locked pulse formation by employing the novel graphene-mediated SA has proven the high performance MLFLs that potentially applicable for a myriad of low-cost nano-devices. View full abstract»

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  • Precise Fault Location in WDM-PON by Utilizing Wavelength Tunable Chaotic Laser

    Page(s): 3420 - 3426
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1507 KB) |  | HTML iconHTML  

    We propose a method to locate precisely faults in wavelength-division-multiplexing (WDM) passive optical network (PON) by using a wavelength tunable chaotic laser. The chaotic laser consists of a multiple-longitudinal-mode Fabry-Perot (FP) laser diode whose modes match the channels of WDM-PON, and an optical feedback loop including a filter. The loop feeds a proportion of light of one mode that passes through the filter back into laser cavity to generate chaotic light. By adjusting the filter frequency, we can tune the wavelength of the chaotic light, and diagnose the corresponding branch of WDM-PON. We demonstrate a proof-of-concept experiment for detection of three ITU channels. Fault location is realized by correlating the back-reflected light with its time-delayed duplicate. The results show that spatial resolution of 2 cm and dynamic range of about 20.8dB can be achieved. In addition, we have experimentally studied the effects of the strength level and wavelength mismatching of the feedback light on the chaotic output of the FP laser. View full abstract»

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  • Data Center Switch Based on Temporal Cloaking

    Page(s): 3427 - 3433
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1390 KB) |  | HTML iconHTML  

    Data centers have become the major technology for collecting, storing, and processing information. The latency requirement for transferring information between servers has become more stringent from year to year as the speed of the new generation of servers increases at an almost exponential pace. In this paper, we propose a new method to compress switching information over data sequence packets using temporal cloaking. The main advantages of this method in comparison to electronic switching or the use of microelectromechanical system technology are that the compression and removal of the switching information are done entirely in the optical domain without increasing the packet duration time, changing or adding overhead bits, reducing the signal-to-noise ratio, or distorting the polarization or the phase of the signal. Only a small delay is added to the signal due to the cloaking process. This method requires tight synchronization; to address this issue, a mathematical model that describes the effect of clock jitter on the system bit error rate performance is derived in this paper. The same concept could also be used to increase the capacity of legacy communication systems as well as in coherent digital communication or analog communication, e.g., radio over fiber. View full abstract»

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  • The Effect of Clock Jitter in Visible Light Communication Applications

    Page(s): 3434 - 3439
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (965 KB) |  | HTML iconHTML  

    Visible light communication (VLC) is an emerging communication technology for short-range applications, especially indoors. This technology uses light, emitted from super-illuminating semiconductors for the primary purpose of illumination, to carry information in addition. One of the major challenges faced in implementing VLC technology is to find a way to achieve communication without affecting the illumination. In this paper, we describe an inverse pulse position modulation method that encapsulates communication data in the time domain without affecting the illumination property, which is conveyed in the amplitude domain. Due to the fact that this modulation method requires accurate synchronization, we have studied the effect of clock time shift and jitter on the system bit-error-rate performance and have derived models that could be used to define the minimum requirements of the synchronization system. View full abstract»

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  • Highly Nonlinear and Dispersion-Flattened Fiber Design for Ultrafast Phase-Sensitive Amplification

    Page(s): 3440 - 3447
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1075 KB) |  | HTML iconHTML  

    The properties of phase-sensitive amplification (PSA) in highly nonlinear fibers are studied. We present a soft glass fiber designed for high nonlinearity and broadband, low dispersion and simulate its performance as a PSA device for ultrafast bitrate signals at 640 Gb/s. The effect of the fiber design parameters on its PSA performance have been studied and the final design has been optimized using a genetic algorithm to have a high nonlinearity and low, flat dispersion. This design has subsequently been compared to other highly nonlinear fibers in order to highlight the effect of both using soft glass and the design and optimization technique. Modelled fiber performance shows squeezing of phase noise in a 5 m length of fiber with 32 dBm total power in the signal and pumps. The fiber length we have used in our model is two orders of magnitude shorter than the state of the art silica based PSA devices for comparable power levels. In addition, fabrication tolerance modelling is done to show that our fiber design is better able to manage fluctuations in the dispersion due to the high nonlinearity. View full abstract»

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  • [Blank page]

    Page(s): 3448
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    Freely Available from IEEE
  • 2012 IEEE International Electron Devices Meeting (IEDM)

    Page(s): 3449
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    Freely Available from IEEE
  • [Call for papers] 2013 IEEE International Conference of Electron Devices and Solid-State Circuits (EDSSC)

    Page(s): 3450
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    Freely Available from IEEE
  • 38th IEEE Photovoltaic Specialists Conference

    Page(s): 3451
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    Freely Available from IEEE

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