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Lightwave Technology, Journal of

Issue 9 • Date May1, 2010

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  • [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): 1285 - 1286
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  • Photonic BandGap Fiber With Multiple Hollow Cores

    Publication Year: 2010 , Page(s): 1287 - 1290
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (907 KB) |  | HTML iconHTML  

    We report the fabrication and characterization of the first photonic bandgap fiber with multiple hollow waveguiding cores. Perspectives for scaling to highly multicore designs are discussed. View full abstract»

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  • Spectral Properties of Locally Pressed Fiber Bragg Gratings Written in Polarization Maintaining Fibers

    Publication Year: 2010 , Page(s): 1291 - 1297
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1111 KB) |  | HTML iconHTML  

    In this work, we analyze the spectral properties of locally pressed fiber Bragg gratings (FBGs) written into polarization maintaining fibers. We study the evolution of the spectral response of a FBG written into a PANDA fiber when the central region of the grating is perturbed by a diametrical load. Due to the complex structure of the fiber, a finite element model was carried out to determine the strain distributions generated at the center region of the fiber core, and hence taking the induced change in refractive index as the change in effective refractive index due to the applied load. Once the shifting in Bragg wavelength and the optical principal axes of the loaded region are known, a modified transfer matrix method is applied to calculate the spectral response of the FBG. We have found experimentally and by numerical simulations that the reflected spectra for the grating exhibit a narrow and tunable polarization-dependent spectral hole. The tuning of this spectral hole is dependent of the magnitude and the angle of the applied force over the optical fiber. View full abstract»

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  • Ultracompact Multimode Interference Coupler Designed by Parallel Particle Swarm Optimization With Parallel Finite-Difference Time-Domain

    Publication Year: 2010 , Page(s): 1298 - 1304
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (973 KB) |  | HTML iconHTML  

    An ultra-compact multimode interference (MMI) coupler with a length ~10 ??m for dense photonic integration is designed by parallel particle swarm optimization (PSO) with parallel finite-difference time-domain (FDTD). The MMI coupler uses a strongly-guiding deep-etched InP platform and the modal analysis of this strongly-guiding deep-etched InP waveguide gives the cross section of the single-mode nanophotonic waveguide, the geometry of the multimode interference region, and the etched-depth requirement. An efficient global optimizer combining parallel PSO algorithm and parallel FDTD is developed, which speedups the optimization and enables automatic nanophotonic design. Two 2 ?? 2 multimode interference couplers with a respective coupling ratio of 50%:50% and 90%:10% are designed as numerical examples using the global optimizer developed and the optimization result shows a ultra-compact multimode interference coupler with a length of ~10 ??m can be achieved with a low excess loss, which is numerically verified by a parallel three-dimensional FDTD. View full abstract»

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  • Architectural Exploration of Chip-Scale Photonic Interconnection Network Designs Using Physical-Layer Analysis

    Publication Year: 2010 , Page(s): 1305 - 1315
    Cited by:  Papers (22)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1554 KB) |  | HTML iconHTML  

    Chip-scale photonic interconnection networks have emerged as a promising technology solution that can address many of the scalability challenges facing the communication networks in next-generation high-performance multicore processors. Photonic interconnects can offer significantly higher bandwidth density, lower latencies, and better energy efficiency. Even though photonics exhibits these inherent advantages over electronics, the network designs that can successfully leverage these benefits cannot be straightforwardly extracted from typical electronic network methodologies and must consider the many unique physical-layer constraints of optical technologies. We conduct an architectural exploration of four chip-scale photonic interconnection networks in a novel simulation environment, measuring insertion loss, crosstalk, and power. We also explain and demonstrate the impact of these physical-layer metrics on the scalability, performance, and realizability of each design. View full abstract»

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  • Characterization of High-Linearity Modified Uni-Traveling Carrier Photodiodes Using Three-Tone and Bias Modulation Techniques

    Publication Year: 2010 , Page(s): 1316 - 1322
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (846 KB) |  | HTML iconHTML  

    The linearity performance of a back-illuminated InGaAs/InP modified uni-traveling carrier photodiode with a highly doped p-type absorber is characterized using three-tone and bias modulation measurement techniques. The bias modulation measurement is used to determine the voltage-dependent relative responsivity, R(V), for a range of photocurrent levels. The results confirm that the photocurrent dependence of the third-order output intercept point (OIP3) as determined by the three-tone method is directly related to the dependence of R(V) on photocurrent. The measured OIP3 show a weak dependence on frequency and a high value of 47.5 dBm at 20 GHz is achieved. View full abstract»

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  • Novel Optical 90 ^{\circ} Hybrid Consisting of a Paired Interference Based 2 ,\times, 4 MMI Coupler, a Phase Shifter and a 2 ,\times, 2 MMI Coupler

    Publication Year: 2010 , Page(s): 1323 - 1331
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1175 KB) |  | HTML iconHTML  

    We propose a novel optical 90?? hybrid consisting of a paired-interference based 2 ?? 4 multimode interference (MMI) coupler, a phase shifter and a 2 ?? 2 MMI coupler. We theoretically clarified that the proposed device shows superior performances to a conventional 4 ?? 4 multimode interference coupler from the viewpoint of a wavelength sensitive loss and an operating bandwidth. We fabricated the proposed 90?? hybrid using a deep-ridge waveguide with a GalnAsP/InP material system, and experimentally demonstrated quadrature phase response with a low interchannel imbalance, a high common-mode rejection ratio (> 20 dB) and a low phase deviation (< 5??) over 94-nm-wide spectral range. View full abstract»

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  • An Analytical Method to Determine Small-Signal Model Parameters for Vertical-Cavity Surface Emitting Lasers

    Publication Year: 2010 , Page(s): 1332 - 1337
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (291 KB) |  | HTML iconHTML  

    A parameter-extraction approach for small-signal model of the vertical-cavity surface emitting lasers (VCSELs), which combines the analytical approach and empirical optimization procedure, is developed in this paper. The cutoff operation of the VCSELs is utilized to extract the values of the pad capacitances, feedline inductance by using a set of closed form expressions derived from cutoff mode input reflection coefficient on wafer measurement. A semianalytical method has been used to determine the extrinsic resistance, and intrinsic oxide aperture junction resistance and capacitance under above-threshold bias condition. An excellent fit between measured and simulated input reflection coefficients under cutoff and above-threshold biased condition in the frequency range of 50 MHz-20 GHz is obtained for VCSELs with different oxide-confined aperture size over a wide range of bias points. View full abstract»

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  • The Influence of Physical Network Topologies on Wavelength Requirements in Optical Networks

    Publication Year: 2010 , Page(s): 1338 - 1343
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (442 KB) |  | HTML iconHTML  

    In wavelength division multiplexed optical networks each connection is assigned a light-path. Given a set of connection requests, how to set up a light-path for each of them is called the static routing and wavelength assignment (RWA) problem. The physical networks impose significant effects on the number of wavelengths required to accommodate all the connections as light-paths are directly set up on it. Wavelength requirements in the small-world and scale-free networks are investigated in this paper for the first time to the best of our knowledge. The two important characteristics of networks are considered: average shortest path length and 1-shell structure. Wavelength requirements in the case of network evolution are investigated, too. Mean light-path length is proved to be directly proportional to the average shortest path length of networks. Simulation results have shown that fewer wavelengths are required in networks with smaller average shortest path lengths, and the rate of increase of the number of wavelengths required is smaller too while traffic load and network size increasing. The emergence of 1-shell structure may result in the increase of the number of wavelengths required due to lack of flexibility in 1-shell structure. The larger the cardinality of 1-shell is, the more wavelengths the network requires. View full abstract»

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  • Ridged LiNbO _{3} Waveguide Fabricated By a Novel Wet Etching/MeV Oxygen Ion Implantation Method

    Publication Year: 2010 , Page(s): 1344 - 1348
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (691 KB) |  | HTML iconHTML  

    We report on a new wet etching/ion implantation method for fabricating ridge waveguide on z -cut LiNbO3. The ridge structures are produced on LiNbO3 crystal by anisotropic wet etching via minus z face. Mode guiding at wavelength of 632.8 nm has been realized by using direct 4.5 MeV oxygen implantation without any implantation mask. The ridge waveguide shows a reduced propagation loss of 1.3 dB/cm after the thermal annealing process. View full abstract»

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  • A Weak-Resonant-Cavity Fabry–Perot Laser Diode With Injection-Locking Mode Number-Dependent Transmission and Noise Performances

    Publication Year: 2010 , Page(s): 1349 - 1355
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (830 KB) |  | HTML iconHTML  

    Quasi-color-free weak Fabry-Perot cavity laser diode with long cavity length is one alternative solution of the wavelength-division-multiplexed passive optical network (WDM-PON) transmitter with comparable broadband gain spectrum and greatly reduced noise figure as compared to typical reflective semiconductor optical amplifiers. In this paper, the amplified spontaneous emission injection-locked weak-resonant-cavity Fabry-Perot laser diode (WRC-FPLD) with 1% front-facet reflectivity directly modulated at 1.25 Gbit/s with detuning injection-locked mode for quasi-color-free transmission in WDM-PON system with channel spacing of 200 GHz is demonstrated. With bias current changing from 0.9 Ith to 1.4 Ith, the improvement on receiving power sensitivity for the WRC-FPLD-based WDM-PON transmitter is up to 9 dB at bit error rate (BER) of 10-9. Increasing the injection-locked mode number from 2 to 3 within temperature variation of 6??C effectively promotes the BER from 10-8 to 10-10 at receiving power of -27 dBm associated with a decreasing power penalty of -3.2 dB. The WRC-FPLD with more injection-locked modes within one channel exhibits higher extinction ratio at higher operating temperature within one injection-locked-mode-number changing period. This elucidates well the cycling evolution on the BER performance of the WRC-FPLD as a function of operating temperature. View full abstract»

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  • Wavelength Converted Broadcast-Selective Buffering Contention Resolution in Synchronous WDM OPS Networks

    Publication Year: 2010 , Page(s): 1356 - 1362
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1102 KB) |  | HTML iconHTML  

    In this paper, we propose a new composed buffer structure termed as wavelength converted broadcast-selective (WCBS). It copies each packet after conversion to all fiber delay lines, and makes the packet management flexible and efficient. By rearranging the packet waiting queue, the highest priority packet can leave the buffer without considering the existing queue, which makes preemption possible. Moreover, we construct an OPS node architecture employing the as-proposed WCBS buffer in output-buffered pattern. Some proper switching strategies are introduced to operate the switching node effectively. An analysis model is established to describe the packets in the node. The minimum packet loss performances under different traffic loads with different buffer parameters are calculated. The results are further verified by simulations. It implies that the WCBS buffer improves the performance of high priority packets effectively, especially when the high priority packet load is low. View full abstract»

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  • Coupling Between the Small-Core-Diameter Dispersion Compensation Fiber and Single-Mode Fiber and Its Applications in Fiber Lasers

    Publication Year: 2010 , Page(s): 1363 - 1367
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (698 KB) |  | HTML iconHTML  

    We investigate the coupling between a small-core-diameter dispersion compensation fiber (SC-DCF) and a single-mode fiber (SMF) and its applications in fiber lasers. The number of interference modes and the power distributed in the interference modes can be selected by controlling the coupling between the core of the SC-DCF and that of an SMF, which can be used to select the lasing oscillation range. Interference pattern with a narrow free spectral range can be obtained with a shorter length of the SC-DCF based intermodal interferometer comparing to that constructed by the common multimode fiber. With the SC-DCF incorporated in an erbium-doped fiber laser (EDFL) cavity, under three different selected coupling conditions, stable dual/triple wavelength switchable EDFLs in three different wavelength ranges are, respectively, achieved by tuning the polarization state of the laser cavity. We also demonstrate its application in four-wave-mixing-based multiwavelength switchable tunable EDFLs. A stable operation of 34 lasing wavelengths is obtained. Multiwavelength switchable tunable EDFLs in two different wavelength ranges are also achieved by controlling the coupling and polarization state of the laser cavity simultaneously. View full abstract»

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  • Bend Loss in All-Solid Bandgap Fibers Revisited

    Publication Year: 2010 , Page(s): 1368 - 1372
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (577 KB) |  | HTML iconHTML  

    The rate of decay of the fundamental guided mode into the surrounding cladding in all-solid photonic bandgap fibers is investigated. Both a simple 1-D model and numerical calculations of realistic fibers show that the decay rate varies asymmetrically across the bandgaps, with larger values near the upper edge of the bandgap. The implications for modeling bend loss in these fibers are discussed. View full abstract»

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  • A 2R Mamyshev Regeneration Architecture Based on a Three-Fiber Arrangement

    Publication Year: 2010 , Page(s): 1373 - 1379
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1489 KB) |  | HTML iconHTML  

    The benefits of using a multi-segmented arrangement of optical fibers for Self-Phase Modulation-based 2R optical regeneration are demonstrated both theoretically and experimentally. Significant improvements in terms of the performance and practicality are achieved. View full abstract»

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  • Temperature Effects on Silicon-on-Insulator (SOI) Racetrack Resonators: A Coupled Analytic and 2-D Finite Difference Approach

    Publication Year: 2010 , Page(s): 1380 - 1391
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2609 KB) |  | HTML iconHTML  

    This paper presents a detailed analysis of racetrack resonators on silicon on insulator substrates. Both the temperature effects and the particularities of silicon nanophotonics are considered throughout the approach. This paper provides a detailed description of the numerical modeling and its application to different designs, while providing several charts and fitting equations. The results presented in this paper can be applied to three major applications: Thermo-optical tuning of optical resonators, thermo-optical modulator and wide range/high sensitivity temperature sensors. While quantifying the temperature effects, this paper also provides useful answers on how critical the temperature parameter is in the optical cavity behaviour. View full abstract»

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  • Characterization of Pressure Response of Bragg Gratings in Grapefruit Microstructured Fibers

    Publication Year: 2010 , Page(s): 1392 - 1397
    Cited by:  Papers (11)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1225 KB) |  | HTML iconHTML  

    In this paper, the pressure response of fiber Bragg gratings in grapefruit microstructured fibers was experimentally investigated and theoretically analyzed with full-vector finite element method. The theoretical calculation agrees well with the experimental results. The pressure changes the refractive index and induces axial strain of the fiber. The radial pressure induces positive strain, but axial pressure induces negative strain. The negative strain dominates. The existence of large air holes make grapefruit microstructured fibers experience larger negative strain than standard single-mode fiber, therefore fiber Bragg gratings in grapefruit microstructured fibers have larger pressure sensitivity than that in SMF. View full abstract»

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  • Eight-Channel WDM Intraboard Optical Interconnect Device by Integration of Add/Drop Multiplexers in Thin-Film Waveguide

    Publication Year: 2010 , Page(s): 1398 - 1403
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (691 KB) |  | HTML iconHTML  

    A wavelength-division-multiplexing (WDM) optical interconnect device has been proposed and investigated in order to realize broadband signal transmission in intraboard chip-to-chip interconnection. Focusing grating couplers (FGCs) and distributed Bragg reflectors were integrated in a thin-film waveguide to form free-space-wave add/drop multi-/demultiplexers for the WDM optical interconnections. This time, FGC coupling efficiency was improved by careful fabrication with multistep deposition and measurements of reflection spectra. An eight-channel WDM interconnect device was fabricated and characterized in the wavelength dependence. View full abstract»

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  • Simple Matrix-Method Modeling for Avalanche Photodetectors With Arbitrary Layer Structures and Absorption/Multiplication Coefficients

    Publication Year: 2010 , Page(s): 1404 - 1413
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1234 KB) |  | HTML iconHTML  

    A simple matrix-method model is presented for calculating the impedance and the short-circuit frequency response of an avalanche photodiode (APD) with arbitrary layer structures and absorption/multiplication coefficients. In our matrix method model, the depletion region of the APD is divided into many thin layers. In each thin layer the absorption and the multiplication coefficients are assumed to be uniform. As an example, we use this matrix-method model to analyze in detail a resonant Ge/Si SACM (separated absorption charge multiplication) APD. The impedance analysis shows that the avalanche region is equivalent to an LCR-circuit including a negative resistance, an inductance with a series resistance, and a capacitance in parallel connection. At higher bias voltages, the negative resistance and series resistance become very small and consequently the LCR circuit shows a strong resonance. Furthermore, the inductance also becomes smaller at higher bias voltages, which introduces a higher resonance frequency. This increases the 3 dB-bandwidth, in agreement with experiment. View full abstract»

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  • Evanescent Semiconductor Active Optical Isolators for Low Insertion Loss and High Gain Saturation Power

    Publication Year: 2010 , Page(s): 1414 - 1419
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (548 KB) |  | HTML iconHTML  

    We have designed evanescent semiconductor active optical isolators to realize lower forward transparent current in transverse electric (TE) mode integrable semiconductor active optical isolators with 9.3 dB/mm optical isolation. Evanescent semiconductor active optical isolators are composed of a semiconductor optical amplifier waveguide with an InGaAsP waveguide layers having an Fe layer at its sidewall upon an MQW active layer, allowing TE-mode optical isolation to be realized without etching the MQW active layer unlike conventional TE-mode semiconductor active optical isolators. Evanescent-mode optical isolators enable higher internal quantum efficiency and lower transparent current, compared with conventional TE-mode optical isolators. Furthermore, it was found that the evanescent-mode optical isolators had higher 3 dB saturation output power. View full abstract»

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  • Spontaneous Emission Rate Enhancement of Silicon Nanocrystals by Plasmonic Bandgap on Copper Grating

    Publication Year: 2010 , Page(s): 1420 - 1430
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2204 KB) |  | HTML iconHTML  

    The spontaneous emission (SE) rate enhancement due to surface plasmon polariton bandgap effect on copper grating was evaluated by calculating the dispersion relation and the electromagnetic field distribution simultaneously. Within the frequency range of silicon nanocrystals (Si-NC) luminescence ((h/2p)??=1.6 eV-1.9 eV), the calculated maximum averaged Purcell factors is about 30-163 for sinusoidal shaped Cu-Si3N4 grating. It is proved that copper can be adopted to enhance the SE of Si-NCs. Since copper is the most commonly adopted metal for silicon integrated-circuit manufacturing, such results pave a promising way for integrating Si emitters on microelectronics chips. View full abstract»

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  • OFS-21

    Publication Year: 2010 , Page(s): 1431
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    Freely Available from IEEE
  • Calls for papers on semiconductor lasers

    Publication Year: 2010 , Page(s): 1432
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Aims & Scope

The Journal of Lightwave Technology contains articles on current research, applications and methods used in lightwave technology and fiber optics.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Peter J. Winzer
Alcatel-Lucent Bell Labs