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Photonics Technology Letters, IEEE

Issue 17 • Date Sept.1, 2013

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Displaying Results 1 - 25 of 34
  • [Front cover]

    Publication Year: 2013 , Page(s): C1
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    Freely Available from IEEE
  • IEEE Photonics Technology Letters publication information

    Publication Year: 2013 , Page(s): C2
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  • Table of contents

    Publication Year: 2013 , Page(s): 1649 - 1650
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  • Editorial

    Publication Year: 2013 , Page(s): 1651 - 1652
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  • Relation of Refractive Index to Ti-Concentration in Near-Stoichiometric {\rm Ti{:}LiNbO}_{3} Waveguide

    Publication Year: 2013 , Page(s): 1653 - 1655
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (469 KB) |  | HTML iconHTML  

    Multi-mode near-stoichiometric (NS) Ti:LiNbO3 planar waveguide was fabricated by co-work of Li-rich vapor transport equilibration and in-diffusion of Ti-film on an initially congruent LiNbO3 substrate. The Ti-concentration is profiled by secondary ion mass spectrometry. The refractive index profile is constructed from measured mode indices and correlated with the Ti-concentration profile. The results show that the index change and Ti-concentration follow an exponential relationship with a power index 0.75/0.49 for the ordinary/extraordinary ray. The relationship is different from that of either conventional congruent waveguide or homogeneously Ti-doped NS bulk material or NS waveguide fabricated by direct Ti-diffusion in an NS substrate. View full abstract»

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  • Digital Microfluidics With Pressure-Based Actuation

    Publication Year: 2013 , Page(s): 1656 - 1659
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (298 KB) |  | HTML iconHTML  

    One of the key issues in biosensors is the time it takes for biomolecules in a solution to reach and bind to the sensor surface (particularly in low-concentration analytes). We present a novel flow scheme without microfluidic channels for label-free biosensors to decrease the delivery time of biomolecules. Through designing the biosensor in such a way that it becomes a membrane with holes, we can apply a droplet on it and push or pull it through the membrane by means of a pressure difference. Contrary to traditional microfluidics for, e.g., flow cells where the analyte flows over the sensor, the flow is now directed through the sensor. We have implemented this scheme in silicon-on-insulator biosensors and have demonstrated in a first proof-of-principle experiment, an improvement in delivery time of at least a factor of three. View full abstract»

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  • QDash-Based Directly Modulated Lasers for Next-Generation Access Network

    Publication Year: 2013 , Page(s): 1660 - 1663
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (475 KB) |  | HTML iconHTML  

    In this letter, we report the strong effect of p-doping on dynamic performances of QDash lasers. Therefore, we demonstrate 10 Gb/s transmission in standard single mode fiber up to 65 km with a dynamic extinction ratio using directly modulated lasers based on this material and commercial Fabry-Pérot etalon filter. View full abstract»

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  • High-Power Pulse Semiconductor Laser-Thyristor Emitting at 900-nm Wavelength

    Publication Year: 2013 , Page(s): 1664 - 1667
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (469 KB) |  | HTML iconHTML  

    High-power pulse semiconductor lasers based on epitaxially integrated thyristor heterostructures were developed. The possibility of generating high-power laser light pulses with duration on the order of 100 ns at control signal amplitude on the order of 40-100 mA at extremely low turn-on thyristor voltage of 10 V was demonstrated. The values reached for the peak pulse optical power and peak pulse current were 28 W and 37 A, respectively. View full abstract»

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  • Fiber Optic Current Sensor Based on Special Spun Highly Birefringent Fiber

    Publication Year: 2013 , Page(s): 1668 - 1671
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (449 KB) |  | HTML iconHTML  

    A fiber optic current sensor based on a polarization-rotated reflected interferometer has been constructed. A special spun highly birefringent fiber is designed and achieved for the sensor by heating and spinning commercial linearly birefringent fiber. In contrast with conventional fibers, the fiber integrates a function of a quarter wave plate. Particularly, fabricating and working principle of the current sensor head using the fiber are expounded. The sensor achieves an accuracy with 0.5% and good linearity shown in temperature dependence (a temperature drift of 0.008%/ °C) over a temperature range 40 °C -70 °C. Further, under simple temperature compensation, the sensor accuracy is within ±0.1% over in a wide range of current and temperature ranges. View full abstract»

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  • Porous Polyethylene Terephthalate Optical Waveguide for Sensing Applications

    Publication Year: 2013 , Page(s): 1672 - 1675
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (423 KB) |  | HTML iconHTML  

    We report the fabrication and characterization of optical waveguides using porous polyethylene terephthalate (PET) film. An optical waveguide is produced by exposing the PET film to cyclotron followed by selective chemical etching. Considering that the average refractive index of porous regions is lower than that of non-porous regions, a waveguide can be formed using a single optical material system. A single-material channel waveguide and an optical splitter were demonstrated using our proposed technique. Through placing a liquid crystal inside the pores, an ethanol gas sensor was obtained with a single-material channel waveguide structure. These PET film waveguides can create new opportunities in various optical applications, particularly in chemical sensing applications. View full abstract»

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  • A Tunable Photonic Double Heterostructure Cavity on Ferroelectric Barium Titanate

    Publication Year: 2013 , Page(s): 1676 - 1679
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1004 KB) |  | HTML iconHTML  

    We designed a photonic double heterostructure cavity on rectangular lattice with an incorporated slot waveguide, which shows high quality factor for both TE and TM modes despite an absence of complete bandgap. The confinement capability of the cavity has been studied using the finite difference time domain method. The ferroelectric barium titanate (BaTiO3) is used as the base material of the proposed cavity. The dispersive and absorptive natures of the material have been incorporated in the calculations. The presence of the slot waveguide improved the quality factor of the cavity, confirming the existing results. Despite the absorptive nature of BaTiO3, the finite extent of the photonic crystal and absence of complete bandgap, the calculated quality factor compares favorably with values reported previously in the literature. View full abstract»

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  • High-Speed Optical Vector and Matrix Operations Using a Semiconductor Laser

    Publication Year: 2013 , Page(s): 1680 - 1683
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (305 KB) |  | HTML iconHTML  

    Using induced transient dynamics of a standard telecommunication laser, we perform optical computation at high data rates. Employing time-multiplexing, we emulate a nonlinear photonic network via a single laser diode. Based on the induced dynamics of the network, a machine learning technique is implemented. We compute the multiplication of a scalar with a vector, vector dot and cross products, and the multiplication of a matrix and a vector, using the same system. Information is injected all-optically at a rate of 5 GSamples/s, allowing for up to 5·108 operations per second. View full abstract»

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  • Integrated Guided-Wave Photodiode Using Through-Absorber Quantum-Well-Intermixing

    Publication Year: 2013 , Page(s): 1684 - 1686
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (675 KB) |  | HTML iconHTML  

    A high-speed, high-saturation power photodiode compatible with a relatively simple monolithic integration process is described. The detector is comprised of an intrinsic bulk absorption layer, an electron drift region, and a field termination layer, and is grown above a main waveguide core comprised of a number of quantum wells, which are used as the active region of a phase modulator. Through-absorber quantum-well-intermixing is used to blue-shift the bandedge of the underlying quantum wells, reducing the optical losses of that material. The detectors demonstrate quantum efficiency, input saturation power, and 3-dB bandwidth of 50 GHz. View full abstract»

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  • 2.7 Mb/s With a 93-kHz White Organic Light Emitting Diode and Real Time ANN Equalizer

    Publication Year: 2013 , Page(s): 1687 - 1690
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (607 KB) |  | HTML iconHTML  

    This letter presents new experimental results on a 2.7-Mb/s organic light emitting diode (OLED) based visible light communications (VLCs) system. We also demonstrate for the first time an online artificial neural network for any VLC system (including inorganics). The major mitigating factors for OLED-VLC systems are the baseline wander phenomenon causing threshold detection to fail and bandwidth limitation caused by low transport mobility, introducing inter-symbol interference into the link and thus the requirement for an equalizer. The online filtering is implemented using the TI TMS320C6713 DSP board and compared with offline results. View full abstract»

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  • Counterpropagating Whispering-Gallery-Modes of Rolled-up Semiconductor Microtubes

    Publication Year: 2013 , Page(s): 1691 - 1694
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    We report on the first experimental demonstration of counterpropagating whispering-gallery-modes (WGMs) of rolled-up semiconductor microtubes. We studied the thermo-optic effect of the microtube and achieved optical-optical modulation in both propagating and counterpropagating WGMs. We also realized a thermal wavelength-switchable fiber ring laser using the counterpropagating WGMs of the microtube. View full abstract»

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  • Bidirectional Polarization Splitting Couplers Based on Dielectric-Coated Metallic Gratings

    Publication Year: 2013 , Page(s): 1695 - 1698
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1328 KB) |  | HTML iconHTML  

    A new bidirectional polarization splitting coupler based on a metal thin film perforated with periodic slits and coated with dielectric is proposed and theoretically investigated. The back-side incident light coupled to the metal-dielectric-air waveguide is split and launched into TM plasmonic and TE photonic modes simultaneously. The operation principle is clarified and theoretically illustrated using the fully vectorial aperiodic Fourier modal method. Polarization extinction ratios better than 15 dB and crosstalk less than 15 dB are achieved for both polarizations over C-band ranging from 1530 to 1570 nm. View full abstract»

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  • Efficient CW Four-Wave Mixing in Silicon-on-Insulator Micro-Rings With Active Carrier Removal

    Publication Year: 2013 , Page(s): 1699 - 1702
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1203 KB) |  | HTML iconHTML  

    Silicon-on-insulator rib waveguides with passive loss of -0.74 dB/cm and free-carrier lifetime reduction via reverse biased p-i-n diodes are used to show efficient continuous wave four-wave mixing with 2 × reduction in required pump power for comparably high conversion efficiency of -8.2 dB, similar to best reports. A conversion efficiency of -13.4 dB is also subsequently achieved using 20 μm radius micro-ring resonators at significantly reduced pump power. View full abstract»

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  • Non-Data-Aided Phase Noise Suppression Scheme for CO-OFDM Systems

    Publication Year: 2013 , Page(s): 1703 - 1706
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (715 KB) |  | HTML iconHTML  

    We propose a non-data-aided phase noise compensation technique that overcomes the limitation of the zero-overhead decision-directed (DD) phase noise suppression method in high-order constellations for coherent optical orthogonal frequency division multiplexing (CO-OFDM) systems. The proposed technique consists of two equalization stages. First, a blind adaptive phase offset recovery scheme based on high-order statics, called the dispersion minimization de-rotator, is applied to subcarrier symbols to achieve rough correction of the common phase error because of phase noise. Second, the conventional DD phase noise correction scheme is used to remove the residual common phase error. The proposed method effectively compensates phase noise without the help of pilot signals, especially for high-order constellation CO-OFDM systems, as confirmed by our simulation results. View full abstract»

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  • Electric Current Tuning the Self-Oscillation Frequency of EC-VCSELs

    Publication Year: 2013 , Page(s): 1707 - 1710
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1160 KB) |  | HTML iconHTML  

    We demonstrate a new way to electrically tune the self-oscillation frequency of an external cavity VCSEL by changing the electrical current injected into the VCSEL, without using any mechanical moving parts. We found that for a self-oscillation frequency from 500 MHz to 4 GHz, the tuning range is up to 15% and the tuning rate is up to 800 MHz/mA. Our experiments and simulation show that the injection current tuning of self-oscillation frequency is due to a change in the VCSEL birefringence induced by changing the injection current. View full abstract»

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  • Distributed Raman Optical Amplification in Phase Coherent Transfer of Optical Frequencies

    Publication Year: 2013 , Page(s): 1711 - 1714
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1106 KB) |  | HTML iconHTML  

    We describe the application of Raman optical-fiber amplification (ROA) for the phase coherent transfer of optical frequencies in an optical fiber link. ROA uses the transmission fiber itself as a gain medium for bi-directional coherent amplification. In a test setup, we evaluated the ROA in terms of ON/OFF gain, signal-to-noise ratio, and phase noise added to the carrier. We transferred a laser frequency in a 200 km optical fiber link, and evaluated both co-propagating and counter-propagating amplification pump schemes. Then, we identified the occurrence of nonlinearities on the signal for non-optimized ROA gain. The frequency at the remote end has a fractional frequency instability of 3·10-19 over 1000 s with the optical fiber link noise compensation. View full abstract»

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  • Energy-Efficient Optical Links: Optimal Launch Power

    Publication Year: 2013 , Page(s): 1715 - 1718
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1159 KB) |  | HTML iconHTML  

    In an optical link, there is a tradeoff between power consumption of transmitter and that of receiver. This letter investigates this tradeoff by developing a power consumption model for the components of the link. The impact of different photonic technologies is studied. A method to minimize the power consumption by optimizing the optical modulation amplitude is discussed. View full abstract»

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  • Symmetrical Encoder for Surveillance of Ring Optical Networks

    Publication Year: 2013 , Page(s): 1719 - 1722
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (369 KB) |  | HTML iconHTML  

    Optical coding has been extensively investigated for monitoring fiber-to-the-X point-to-multipoint passive optical networks. In this letter, we propose to extend this type of coding for ring based metropolitan networks. We show that this new application requires a novel design for the optical coding devices, which we call symmetrical encoders. We propose one implementation of this encoder and examine its suitability to monitor faults in each segment of the ring and also to detect faulty nodes. In addition, we evaluate the performance of the system in terms of signal-to-noise ratio and network recovery time. View full abstract»

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  • A CO-OFDM System With Almost Blind Phase Noise Suppression

    Publication Year: 2013 , Page(s): 1723 - 1726
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1056 KB) |  | HTML iconHTML  

    We propose a high spectral efficiency coherent optical orthogonal frequency division multiplexing system utilizing a novel and almost blind phase noise compensation method. With the aid of pseudo pilots instead of pilots, laser phase noise can be suppressed effectively while the overhead of system is reduced successfully. Numerical results show that the performance of the proposed pseudo pilot-aided phase noise compensation scheme can approach that of the pilot-aided counterpart, yet achieve higher spectral efficiency even when the phase noise is severe. View full abstract»

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  • Improved Performance of Plasmonic Thermal Emitter via Incorporation of Gold Nanoparticles

    Publication Year: 2013 , Page(s): 1727 - 1730
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1120 KB) |  | HTML iconHTML  

    The improved performance of plasmonic thermal emitter by incorporating randomly distributed gold nanoparticles is demonstrated in the mid-infrared range. Gold films with different thicknesses were deposited on top of the devices and then annealed to form separate nanoparticles. Experimental results showed that the size and distribution of nanoparticles depend mainly on the gold film thickness, rather than annealing temperature. It is observed that thermal emitters with smaller particles embedded exhibit significant enhancement in emission intensity. It is the strong scattering between gold nanoparticles that contributes to the enhanced infrared thermal emission. As an efficient mid-infrared radiation source, this device has the potential to be applied in various fields such as second harmonic generation of infrared source and biosensors. View full abstract»

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  • Study on Phase Interpolation Filters for Coherent Optical Communications

    Publication Year: 2013 , Page(s): 1731 - 1733
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (354 KB) |  | HTML iconHTML  

    In most of the carrier phase estimation (CPE) algorithms, there is a need to average a block of symbols to mitigate the noise effect. The symbols within a block may share the same derived phase (block estimation), or alternatively, a symbol by symbol sliding-window filter can be used to get each symbol a unique phase (sliding-window estimation). It is well-known that block estimation has lower estimation accuracy but consumes less computational power compared with sliding-window estimation. To improve the performance of CPE employing block estimation, we study and propose a phase interpolation filter that is simpler than the sliding-window filter, and show analytically that linear phase interpolation yields the best performance. Simulation and experimental results show that the phase interpolation filter effectively improves the performance of block estimation to the level similar to that of the sliding-window estimation. View full abstract»

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Aims & Scope

This letters journal addresses all aspects of the IEEE Photonics Society Constitutional Field of Interest with emphasis on photonic/lightwave components and applications, laser physics and systems and laser/electro-optics technology.

Full Aims & Scope

Meet Our Editors

Editor-in-Chief
Dr. Seb J. Savory
University College London