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Lightwave Technology, Journal of

Issue 21 • Date Nov.1, 2010

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Displaying Results 1 - 25 of 29
  • [Front cover]

    Publication Year: 2010 , Page(s): C1
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  • Journal of Lightwave Technology publication information

    Publication Year: 2010 , Page(s): C2
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  • Table of contents

    Publication Year: 2010 , Page(s): 3047 - 3048
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  • Low Coherent Optical Frequency Domain Reflectometry Interrogates Fiber Bragg Grating Sensors

    Publication Year: 2010 , Page(s): 3049 - 3054
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (551 KB) |  | HTML iconHTML  

    A novel fiber optical reflectometry is proposed for long distance measurements and sensing applications. The reflectrometric information is included in the phase difference of two interfering light beams reflected at the same scattering point on the fiber under test (FUT). The reflection position and local information can be determined by modulating the frequency difference and analyzing the reflecting signal in frequency domain. Theoretical analysis and experimental demonstration are presented. Two adjacent reflection points 50 km away from the reflectometry with a gap of 11 meters between each other is distinguished. It is estimated that the operating range could be over 500 km theoretically by employing a light source with 0.3 nm bandwidth. This novel reflectometry is applied as a fiber Bragg grating interrogation solution as an example. View full abstract»

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  • Similar Structures, Different Characteristics: Optical Performances of Circular Polarizers With Single- and Double-Helical Metamaterials

    Publication Year: 2010 , Page(s): 3055 - 3061
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1168 KB) |  | HTML iconHTML  

    A novel metamaterial with double-helical wire structures was proposed to construct optical circular polarizers which have boarder wavelength bands than those with single-helical structures. In this work, we systematically studied the dependence of optical properties of the double- and single-helical circular polarizers on their length of helix-period, spacing of grid, number of helix-period, diameter of helix, and diameter of wire. The simulation results show that the double-helical circular polarizers have much broader operation bands than the single-helical ones but have considerably lower extinction ratios for all structural parameters. In addition, the influences of the structural parameters on the optical performances are quite distinct between the single- and double-helical structures. This paper summarized the main influences, which is of certain directive significance to related experimental studies. View full abstract»

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  • Optically Powered Communication System With Distributed Amplifiers

    Publication Year: 2010 , Page(s): 3062 - 3069
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1102 KB) |  | HTML iconHTML  

    An optically powered communication system with distributed amplification is demonstrated using either distributed parametric amplification (DPA) or distributed Raman amplification (DRA) within the dispersion-shifted fiber (DSF) and single-mode fiber (SMF). At the fiber output the residual pump after the distributed amplification is recycled to power the receiver component. Our scheme is also a potential candidate for the `last mile' transmission. Based on our scheme, 4 channels of 10 Gb/s WDM signals are used to obtain practical performance evaluation. In the presence of 10-dB gain for signals, the power penalties of 1.35 -dB at the BER of 10-9 are achieved for DPA in DSF, and as the comparing counterpart of DPA, counter-pumping DRA induce approximately the same level of power penalty (1.55-dB) in DSF and 1.96 -dB in SMF. Co-pumping DRA are also tested in both kind of fibers. Finally, the energy-efficiency issue for different pumping schemes is analyzed. View full abstract»

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  • Tunable Lattice-Form Mach–Zehnder Interferometer for Arbitrary Binary Code Generation at 40 GHz

    Publication Year: 2010 , Page(s): 3070 - 3078
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1466 KB) |  | HTML iconHTML  

    We use the direct temporal domain approach to design spectrally periodic optical filters for pulse repetition rate multiplication (PRRM) with envelope shaping. In particular, we demonstrate a tunable lattice-form Mach-Zehnder interferometer using Silica-based planar lightwave circuit (PLC) for arbitrary 4-bit binary amplitude code generation at 40 GHz and to increase the repetition rate of a 10 GHz input pulse train to 20 GHz or 40 GHz. In addition to PRRM and envelope shaping, the device also has the capability of arbitrary phase coding. View full abstract»

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  • Performance Evaluation of Nondegenerate Wavelength Conversion in a Silicon Nanowire Waveguide

    Publication Year: 2010 , Page(s): 3079 - 3085
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1060 KB) |  | HTML iconHTML  

    The performance of wavelength conversion based on nondegenerate four-wave mixing (FWM) with two pumps is theoretically evaluated in a silicon nanowire waveguide. A theoretical model is developed to take into the limitations of nonlinear loss parameters on conversion bandwidth, efficiency, and uniformity. Analysis shows that the conversion bandwidth of two-pump nondegenerate FWM is > 30% broader than the conversion bandwidth of the degenerate FWM without compromising the conversion efficiency under the same pump power level. Also the results indicate that the improvement originates from efficient phase matching over broader bandwidth range due to two-wavelength pumps. View full abstract»

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  • Indoor High-Bandwidth Optical Wireless Links for Sensor Networks

    Publication Year: 2010 , Page(s): 3086 - 3094
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1050 KB) |  | HTML iconHTML  

    Emergence of sensor networks for data-procurement in wide-ranging applications, including defense, medical, environmental and structural health monitoring, has led to development of low-power miniature devices employing radio frequency (RF) communications. In contrast to RF, optical devices are smaller and consume less power; reflection, diffraction, and scattering from aerosols help distribute signal over large areas; and optical wireless provides freedom from interference and eavesdropping within an opaque enclosure. Optics can accommodate high-bandwidth transmission of multimedia in aircrafts, where RF is shunned due to interference with control signals. These motivate use of optical wireless as a mode of communication in sensor networks. We have set up and experimented on an infrared laser transceiver test-bed with ceiling used as reflector to establish an intensity-modulated/direct-detected (IM/DD) link. Frequency measurements are conducted to characterize the link up to 1 GHz, and are transformed to obtain impulse responses and eye diagrams. These experimental findings demonstrate the capability of indoor optical wireless links of delivering 1 gigabit per second and beyond, without intersymbol interference. Thus, a broadband infrastructure can be deployed allowing high-quality audio-visual data communication among sensor nodes. View full abstract»

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  • Resonance in Link RF Gain by Negative Photocurrent Resistance of Electroabsorption Modulator Under Very High Optical Power

    Publication Year: 2010 , Page(s): 3095 - 3099
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (319 KB) |  | HTML iconHTML  

    We examine the photocurrent effect in the electroabsorption modulator (EAM) under very high optical power and investigate its implication in the link radio-frequency (RF) gain. After reviewing the effect of the photocurrent in the EAM, using the voltage-source model with the device capacitance included, we demonstrate a possibility that the RF gain can be enhanced by resonance due to the photocurrent if the photocurrent decreases with device bias, exhibiting negative differential resistance. We explore an EAM with intrastep quantum wells showing blueshift to achieve the negative photocurrent resistance and demonstrate a case where an enhancement in the link RF gain is possible. View full abstract»

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  • Low Noise Optically Tunable Opto-Electronic Oscillator With Fabry–Perot Etalon

    Publication Year: 2010 , Page(s): 3100 - 3106
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (983 KB) |  | HTML iconHTML  

    A low noise optically tunable optoelectronic oscillator (OEO) scheme which uses a 1000 finesse Fabry-Perot etalon as the mode selector is demonstrated. The dependency of input optical frequency on RF frequency is theoretically analyzed and experimentally shown. The etalon-based OEO is compared with the standard OEO with RF filter and the results show higher RF frequency stability and lower phase noise. A single optical side band modulation technique is also used to improve the spectral purity and the results are compared with the double side band modulation technique. Low noise operation of an optically tunable OEO is achieved by using optical single side band modulation. View full abstract»

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  • Transmission Effects in Wavelength Division Multiplexed Chaotic Optical Communication Systems

    Publication Year: 2010 , Page(s): 3107 - 3114
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1055 KB) |  | HTML iconHTML  

    In this study we present the influence imposed by the coexistence of wavelength division multiplexed (WDM) channels on a chaotic optical communication system tested in an installed network environment. Both conventional carriers that carry 10 Gb/s data sequences and chaotic carriers used for data-encrypted channel transmission have been considered in a dense WDM configuration. Inter-channel interference, channel polarization and cross-phase modulation are some dominant phenomena identified to affect the synchronization process of well-match chaotic optical oscillators. The efficiency of data recovery of the conventional and chaos encrypted channels is analyzed. 1.25 Gb/s data sequences, that are completely hidden propagate along the transmission link, are finally recovered by the authorized receiver-using forward error correction (FEC) methods-with bit error rates (BER) below 10-12, for channel spacing of 0.8 nm and in parallel polarized adjacent channels. When orthogonal polarization states are employed the channel spacing can be further reduced to 0.65 nm without sacrificing in the recovery performance. View full abstract»

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  • Compact and Low Power Consumption Hybrid Integrated Wavelength Tunable Laser Module Using Silicon Waveguide Resonators

    Publication Year: 2010 , Page(s): 3115 - 3120
    Cited by:  Papers (19)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1033 KB) |  | HTML iconHTML  

    Silicon photonics is expected to reduce size and cost of photonic devices and realize large scale photonic integrated circuits for telecom and datacom applications. In this paper, we demonstrate a compact wavelength tunable laser module using hybrid integrated semiconductor optical amplifier and silicon waveguide resonators. The power consumption of the laser module is 1 W to obtain +8 dBm fiber coupled power under the module temperature of 70°C. Such integration technology broadens design flexibility of silicon-based photonic devices and their applications. View full abstract»

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  • Polarization-Insensitive Variable Optical Attenuator and Wavelength Blocker Using Liquid Crystal Polarization Gratings

    Publication Year: 2010 , Page(s): 3121 - 3127
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (424 KB) |  | HTML iconHTML  

    We demonstrate a variable optical attenuator (VOA) based on liquid crystal polarization gratings (LCPGs), which eliminates the need for complex polarization management found in competing LC technologies. We then configure the VOA as a multi-channel wavelength blocker resulting in a simple, compact architecture with high performance and low cost. Together with a dual fiber collimator, relay lenses, a diffraction grating, a quarter wave plate, and a mirror we achieve optical attenuation of ~50 dB with minimal polarization dependent loss (≤ 0.3 dB) and insertion loss ( ≤ 2.5 dB). The device also manifests competitive wavelength flatness (≤ 0.35 dB variation), response times ( ~ 40 ms), and temperature dependent loss (≥ 47 dB maximum attenuation up to 85°C). We describe the principle of operation, explain the fabrication process and optimization challenges, and finally present the system design and experimental results for a four-channel, 100 GHz wavelength blocker in the C-band. View full abstract»

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  • Rate Equation Analysis of High Speed Q-Modulated Semiconductor Laser

    Publication Year: 2010 , Page(s): 3128 - 3135
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (320 KB) |  | HTML iconHTML  

    Dynamic response of a Q-modulated semiconductor laser is simulated based on a rate equation model. Numerical results from both small-signal and large-signal analyses show that the Q-modulation has much higher bandwidth limit and smaller wavelength chirp than the direct modulation. It is shown that a high-extinction-ratio, low-chirp modulation of 40 GHz RZ signal can be achieved and the effects of various parameters on the Q-modulation are discussed. In addition to high-speed communications, the Q-modulated laser is particularly suitable for microwave carrier generation in radio-over-fiber systems. View full abstract»

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  • Variational Approach to Power Evolution in Cascaded Fiber Raman Laser

    Publication Year: 2010 , Page(s): 3136 - 3141
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB) |  | HTML iconHTML  

    A variational approach is formulated and implemented for numerically solving a system of nonlinear two-point boundary value problem (BVP) with coupled boundary conditions modeling the power evolution in cascaded fiber Raman laser with the fiber Bragg gratings at the ends of the cavity. The nonlinearity is treated by successive linearization and the coupled boundary conditions are naturally incorporated into the system through integration in the variational setting. A global approximation of the dependent variables in terms of Legendre polynomials is used to provide a stable Lagrangian interpolation representation as well as the Legendre-Gauss quadrature for accurate numerical evaluation of integrals in the variational formulation. An initial approximate solution is constructed for the delicate convergence to the solution. The approach is validated against an approximate analytic solution and some exact integrals of the variables. The numerical experiments show exponential (spectral) accuracy achieved with much lower resolution in comparison to a widely available BVP solver. Further numerical experiments are performed to reveal the physical characteristics of the underlying model. View full abstract»

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  • Static and Dynamic Response Analysis of Raman Injection Quantum Cascade Laser Using Circuit Level Modeling

    Publication Year: 2010 , Page(s): 3142 - 3148
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (569 KB) |  | HTML iconHTML  

    In this paper a new approach for modeling of Raman quantum cascade lasers (QCLs) is presented which integrates electrical, optical and Raman effects. The equivalent circuit model of laser by employing simplified two-level rate equations of pump and Raman regions is developed. The total equivalent circuit is composed of pump laser circuit coupled to Raman laser circuit which models the behaviors of each component and whole device. By using the presented model the static and dynamic performances of laser for different parameters are investigated. The results of simulation show that the main characteristics of laser such as threshold current, quantum efficiency, output power and modulation response are affected by photon lifetime and variation of population inversion conditions. Static results of model agree favorably with experimental data from devices reported in the literatures. View full abstract»

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  • Interrogation of a Suspended-Core Fabry–Perot Temperature Sensor Through a Dual Wavelength Raman Fiber Laser

    Publication Year: 2010 , Page(s): 3149 - 3155
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (551 KB) |  | HTML iconHTML  

    The interrogation of a Fabry-Perot cavity through a dual wavelength Raman fiber laser is reported. The proposed sensing system is based on the use of a dual wavelength Raman fiber laser to generate two quadrature phase-shifted signals that allow the recovery of the temperature change sensed by the Fabry-Perot interferometric cavity. The dual wavelength Raman fiber laser is based on fiber Bragg gratings combined with a distributed mirror. The Fabry-Perot cavity is fabricated by splicing a short length of a suspended-core microstructured fiber to a single mode fiber. The use of this sensing system allows a passive and accurate interrogation of the temperature, while taking advantage of the Rayleigh scattering growth as a distributed mirror in the laser. View full abstract»

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  • Limits of Stimulated Brillouin Scattering Suppression in Optical Fibers With Transverse Acoustic Waveguide Designs

    Publication Year: 2010 , Page(s): 3156 - 3161
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1206 KB) |  | HTML iconHTML  

    A major approach investigated recently for stimulated Brillouin scattering (SBS) suppression in fiber amplifiers for high power single frequency fiber lasers is to explore designs of acoustic waveguide in optical fibers. This acoustic waveguide can be implemented to some extent independent of the optical waveguide by using a combination of dopants which modify the host glass by varying levels in acoustic and optical properties. Although this approach provides some SBS suppressions, the new analysis described in this work, considering the often omitted leaky acoustic modes, demonstrates its limit. A complex acoustic mode solver, reported in details elsewhere, was recently developed to find solutions for simultaneous longitudinal and shear acoustic wave equations which satisfy rigorous boundary conditions in an arbitrary circular acoustic waveguide. By taking advantage of this new tool, it is possible to find the leaky acoustic modes for acoustic waveguides designed for SBS suppressions. In these acoustic waveguides, the guided acoustic modes often have a reduced overlap with the optical modes by design and, sometimes, do not exist at all, while the leaky acoustic mode can have a significant stronger overlap with the optical modes and, consequently, can play a dominant role in the SBS gain spectrum. It is, therefore, critical to consider the leaky acoustic modes in these cases. Two prominent transverse acoustic waveguide designs proposed recently for SBS suppression in optical fibers are studied here. This work reports, for the first time, the limits of these designs for SBS suppression. With consideration of the leakage acoustic modes, some new insights are provided on the underlying physics as well as on how to optimize these designs for optimal SBS suppression. View full abstract»

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  • Formulation of a Complex Mode Solver for Arbitrary Circular Acoustic Waveguides

    Publication Year: 2010 , Page(s): 3162 - 3175
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1525 KB) |  | HTML iconHTML  

    There has been a resurgence of interests in stimulated Brillouin scattering (SBS) in optical fibers recently. This is largely due to the need to overcome SBS for power scaling of single frequency fiber lasers. Complex acoustic waveguide designs have been proposed for SBS suppression in optical fibers. There is, therefore, a strong need for finding acoustic modes in complex acoustic waveguides. Furthermore, leaky acoustic modes are often ignored in recent works on SBS in optical fiber. Many leaky acoustic modes involved in SBS in optical fibers often have comparable losses to guided acoustic modes. The losses of both guided acoustic modes and many leaky acoustic modes are dominated by the extremely high material loss of acoustic waves in the GHz region in optical fibers. Therefore, it is very important to consider these leaky acoustic modes in SBS in optical fibers, especially for acoustic antiguide designs used for SBS suppressions, where those leaky acoustic modes are often responsible for the peak SBS gain and consequently SBS threshold. Even for optical fibers with guided acoustic waveguide, fine features in SBS gain spectra can be better understood by studying the additional contributions from leaky acoustic modes. In this work, we report, for the first time, a complex vector acoustic mode solver capable of finding both guided and leaky acoustic modes in arbitrary circular acoustic waveguides. The validity of the mode solver is verified by comparing simulated SBS gain spectra in two optical fibers, one with acoustic guide and one with acoustic antiguide, to measured ones. This acoustic mode solver can be used to provide highly accurate SBS gain spectrum in optical fibers. It will be a critical tool in optical fiber designs for SBS suppressions and enhancements. It will also be very important tool for understanding fine spectral details of SBS in optical fibers. View full abstract»

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  • Photonic Chip-Based Simultaneous Multi-Impairment Monitoring for Phase-Modulated Optical Signals

    Publication Year: 2010 , Page(s): 3176 - 3183
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (915 KB) |  | HTML iconHTML  

    We report the first experimental demonstration of simultaneous multi-impairment monitoring of phase-modulated 40 Gbit/s nonreturn to zero differential phase-shift keying (NRZ-DPSK) and 640 Gbit/s return-to-zero (RZ)-DPSK optical signals. Our approach exploits the femtosecond response time of the Kerr nonlinearity in a centimeter-scale, highly nonlinear, dispersion engineered chalcogenide planar waveguide to perform THz bandwidth RF spectrum analysis. The features observed on the radio-frequency (RF) spectrum are directly utilized to perform simultaneous group velocity dispersion and in-band optical signal-to-noise ratio (SNR) monitoring. We also numerically investigate the measurement accuracy of this monitoring technique, highlighting the advantages, and suitability of the chalcogenide rib waveguide. View full abstract»

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  • Correction to “Tunable Wavelength Conversion by XPM in a Silicon Nanowire and the Potential for XPM-Multicasting” [Sep 10 2499-2511]

    Publication Year: 2010 , Page(s): 3184
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (22 KB) |  | HTML iconHTML  

    In the above titled paper (ibid., vol. 28, no. 17, pp. 2499-2511, Sep. 10), there were errors which are corrected here. View full abstract»

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  • Blank page

    Publication Year: 2010 , Page(s): 3185 - 3186
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  • IEEE International Vacuum Electronics Conference

    Publication Year: 2010 , Page(s): 3187
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    Freely Available from IEEE
  • OFCNFOEC

    Publication Year: 2010 , Page(s): 3188
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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