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Photonics (ICP), 2011 IEEE 2nd International Conference on

Date 17-19 Oct. 2011

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Displaying Results 1 - 25 of 83
  • [Front cover]

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    Freely Available from IEEE
  • [Copyright notice]

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    Freely Available from IEEE
  • High resolution optical microscopy with electron-beam excitation

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1494 KB) |  | HTML iconHTML  

    We have developed an electron beam excitation assisted near-field scanning optical microscope and demonstrated resolution greater than 50 nm. The microscope has a few tens nanometer spatial resolution laterally and makes it possible to observe dynamic behaviors of living biological specimens in various surroundings such as air or liquids. In the microscope, a light source in a few nanometers size is excited by focused electron beam in a luminescent film. Scan speed of nanometric light source is faster than that of the small aperture in conventional near-field scanning optical microscopes. The optical near-field microscope enables to observe optical constants such as absorption, refractive index, polarization properties, and its dynamic behaviors in nanometer scale. The developed microscope opens new microscopy applications to in nano-technology and nano-science. We also present direct excitation of fluorescented labelling cells. View full abstract»

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  • Long-period fiber grating with multi resonant wavelengths fabricated by a CO2 laser for distributed sensing

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    A multi long-period grating (multi-LPG) sensor was investigated and fabricated by a CO2 laser for distributed sensing to detect abnormal high temperatures of a nuclear power generator and a large-scale chemical plant. To fabricate the multi-LPG sensor, a carved LPG was introduced for easy fabrication of the multi-LPGs with different resonant wavelengths in a similar loss spectrum. It was investigated experimentally how the CO2 laser beam is scanned for the carving. The influence of the irradiated energy of the CO2 laser on carving has been clarified, and it was found that a minimum irradiated energy of the CO2 laser existed, and the value was determined to be 0.23 J/mm. As a result, the carved LPG could be fabricated and the resonant wavelength could be shifted successfully for the distributed sensor. The procedures for the fiber carving and the fundamental characteristics of the carving are described in details. View full abstract»

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  • All-optical regeneration based on phase sensitive amplification

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    We review our recent results regarding regeneration of binary phase encoded signals using phase sensitive amplification in fibers. View full abstract»

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  • Microfiber-based devices: Current sensor and tunable laser

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    Microfibers and its knot resonator structure are fabricated using a flame-brushing technique for current sensor and tunable Erbium-doped fiber laser (EDFL) applications. A compact current sensor using a microfiber knot resonator (MKR) is demonstrated based on idea of measuring the thermally induced resonant wavelength shift as a result of heat produced due to the flow of electric current over a copper rod. A tunable fiber laser is also demonstrated using a MKR structure made by a highly doped Erbium fiber. A stable laser output is achieved at 1533nm region with a signal to noise ratio (SNR) of 15dB. With the assistance of a copper wire touching the circumference of the ring, the peak wavelength of the laser can be tuned from 1533.3nm to 1533.9nm as the loading current is increased from 0 to 1.0 A. View full abstract»

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  • Switching the negative refractive index and surface wavevector of superconducting metamaterials

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    A metamaterial made of metallic and superconducting split ring resonators shows negative refractive index and the tangential wavevectors for s- and p- polarized light, depending on the fraction of the superelectrons. The temperature dependence of the superconductors is useful for switching the directionality of light beam. View full abstract»

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  • Improved CAR and noise analysis for photon-pair generation in an ultra-compact silicon slow-light photonic crystal waveguide

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    We report the improvement and noise analysis of correlated photon-pair generation in an ultra-compact 96 μm long dispersion-engineered silicon slow-light photonic crystal waveguide pumped by picosecond pulses. The key metrics for a photon-pair source: coincidence to accidental ratio (CAR) and pair brightness were measured to be a maximum 27 at a pair generation rate of 0.002 pair per pulse. We performed the noise analysis by comparing the single and coincidence count rate at the output end of the waveguide. The noise analysis shows that detector dark counts, leaked pump light, linear and nonlinear losses, multiple pair generation and detector jitter are the limiting factors to the CAR performance of the sources. View full abstract»

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  • Integrated diffractive optical elements for optical sensors applications

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    The paper presents design, modeling, fabrication and analysis of integrated diffractive optical elements (DOEs) for optical sensor applications. The sensors presented depend on two major mechanisms: Surface Plasmon Resonance (SPR) and Guided Mode Resonance (GMR). In SPR-based sensor, DOEs are implemented on the backside of the sensor chip for an in/out coupler at large angle of operation. The proposed scheme introduces a compact optical system, while the resolution maintains no more than 10-5 RIU. In GMR-based sensor, the novel structure is proposed to increase the sensor's sensitivity. The device geometry comprises of a sensing region (cladding layer) embedded between a sub-wavelength grating and a high index film. The changes of the sensing region optical properties influent the phase matching condition between the diffracted wave and the guided/cladding mode and hence resonance shifts. The sensitivity is directly proportional to the power confinement inside the sensing region. With a proper modal excitation, the sensitivity can be dramatically enhanced up to 32 times. View full abstract»

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  • Fiber optics devices based on selective modal excitation

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    Inside any wave-guiding structure, such as optical fibers, light propagates in a discrete set of modes. Each mode is defined by its direction of propagation, amplitude profile, phase distribution and polarization. Proper modal excitation and manipulation can yield to novel and low cost optical devices. This paper covers the concepts of designing low cost and functional optical fiber devices based on selective modal excitation. On-axis single mode to a multimode fiber coupling, for example, selectively excites radial modes only. Controlling the phase properties between these modes produces an all-fiber band-pass filter when connecting another single mode fiber at the output. A controllable band-rejection fiber is produced through off-axis excitation of large-mode area fiber with fiber Bragg grating (FBG) inscribed on it. Utilizing long period fiber grating, a simple all-fiber device that can transform a Gaussian-shaped laser beam into a uniform intensity beam is achieved. The device is based on the interaction of a core mode and a cladding mode partially coupled out by the grating. View full abstract»

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  • Suppression of the Phase Induced Intensity Noise based on the Dynamic Cyclic Shift code for SAC-OCDMA access networks

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (284 KB) |  | HTML iconHTML  

    A new code family for Spectral Amplitude Coding Optical Code Division Multiple Assess (SAC-OCDMA) system has been proposed in this paper. The new code family we call it Dynamic Cyclic Shift (DCS) code. The DCS code has many advantages. However, the DCS code can be generated without code parameter limitation. In addition, the shorter code length and variable cross correlation (λc ≤ 1) of the DCS code can improve the SAC-OCDMA system performance. The mathematical results and simulation analysis shows that the DCS code in terms of the Bit-Error-Rate (BER) and eye diagram can effect on the suppression of Phase Induced Intensity Noise (PIIN). The simulation analysis carried the data rate 10 Gbps for 20 km with low BER value comparing with former SAC-OCMA code systems. View full abstract»

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  • Modeling and simulation of Multi Diagonal code with zero cross correlation for SAC-OCDMA networks

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    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (2019 KB) |  | HTML iconHTML  

    A new code family has been proposed for the Spectral Amplitude Coding-Optical Code Division Multiple Access (SAC-OCDMA) networks. This new Multi Diagonal (MD) code family, proposed for SAC-OCDMA applications due to his advantage such as; the cross-correlation value still zeros in case of an increase the number of users for any weight value. Furthermore, the DCS code supports a large number of users and easy code construction. Based on the theoretical analysis MD code is shown here to provide a much better performance compared to Modified Quadratic Congruence (MQC) code and Random Diagonal (RD) code. Proof-of-principle simulations of encoding with 5 users with 10 Gbps data transmission at a BER of 1.1×10-13 have been successfully demonstrated together with the DIRECT detection scheme for 40 km fiber length without any amplification or side pumping. View full abstract»

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  • Variable sensitivity laser range finder receiver

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    A variable sensitivity laser range finder receiver is designed and developed based on variable offset and threshold strategy with noise and dc effect cancellation technique. This receiver operates with 50 ns pulse. The frequency of operation is adjusted to 200 MHz. It means that the time intervals as short as 5 ns can be measured resulting in a distance accuracy of 0.75 m, which is a good accuracy for long distance measurement. FPGA not only converts the time to corresponding distance but also performs high accuracy operation. View full abstract»

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  • Development and characterization of tunable laser based optical time domain reflectometer

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    Fiber line monitoring system is crucial in the operation of optical communication networks to minimize the system interruptions due to fiber faults. A tunable laser based optical time domain reflectometer (TL-OTDR) is developed for the purpose of detecting breakages in the fiber link. The TL-OTDR is able to inject optical pulses with different wavelengths to the fiber link and the reflected light is analyzed by the OTDR. With the integration of optical filters at the fiber ends, fiber fault at the branch can be identified by the TL-OTDR compared to the conventional OTDR which is only able to detect faults in the core fiber. An L-band tunable laser is deployed as the laser source of the OTDR without interrupting the fiber to the home (FTTH) transmission at C-band wavelengths. The TL-OTDR is characterized and the results are reported. View full abstract»

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  • Impact of cross-phase modulation on 320 Gbps WDM-PON architecture

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    In this paper, we proposed and demonstrated through experiment the effect of cross-phase modulation nonlinearities on a simulated WDM-PON downstream optical link. It is reported that within certain channel spacing, crosstalk induced by XPM increases rapidly, despite increases in transmission power. Thus, the dependency of XPM on different link parameters such as transmitted channel spacing, link length and interacting channel bit rate are the focus areas of our investigations. Using the pump-probe method, we use the pump channel to act as an interfering signal on the transmission channel band and by varying the interfering channel spacing from 12.5, 25, 50 and 100 GHz WDM-PON; we can observe its impact on the transmission channel. Evaluation of Eye diagram, Q penalties and BER are being performed. From the results, it can be observed that cross-phase modulation occurs in two conditions, that is during dense WDM channel spacing of below 25 GHz, as per the ITU-T G.694.1 recommendation and during superimposition of the pump signal and transmission band channel in time, for this experimentally simulated WDM-PON network architecture. View full abstract»

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  • New design of Zero Cross Correlation Codes for Spectral Amplitude Coding in OCDMA systems

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    A new design code structure for Spectral Amplitude Coding with zero cross- correlation in Optical Code Division Multiple Access (OCDMA) has been proposed in this paper. The proposed code called Modified Zero Cross Correlation Code (MZCC). MZCC code provides much easier code construction, given any number of users K and weights to have minimum code length. MZCC code will be demonstrated using OptiSys 6.0. The results indicated that MZCC code is truly performs better in term of noise performance compared with existing Optical CDMA codes. View full abstract»

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  • Wick's symbol approach to the impurity bound fröhlich polaron

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    Upper bound estimates for the ground state energy of quantized Fröhlich's model of the free and impurity bound Landau-Pekar polaron were derived by means of a variational method based on the Wick symbol formalism and the theory of coherent states. The bounds so obtained are valid at arbitrary electron-phonon coupling strength. The proposed approach allows for generalization to the case of the Fröhlich polaron model in external magnetic Held as well as to various quantum models of polarons confined by external potentials, thus forming polaronic quantum dots. View full abstract»

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  • SEM-EDX investigations of magnetron sputtered ZnO thin films

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    Zinc oxide (ZnO) is a promising electronic material for transparent electronic applications including thin-film sensors, transistors and solar cells. In this work, we investigated the influence of direct current (DC) magnetron sputtering process parameter on ZnO films using scanning electron microscopy (SEM). The experimental results reveal an enhancement of the structural properties with increasing argon (Ar) pressure. The influence of the Ar pressure will be discussed in this paper. View full abstract»

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  • Fiber optical parametric amplifier with dispersion flattened photonics crystal fiber as a gain medium

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    A fiber optical parametric amplifier utilizing single continuous wave pump is demonstrated. Gain medium used for parametric amplification is a 50 m long dispersion flattened photonics crystal fiber. The relatively wide bandwidth of pump is able to suppress stimulated Brillouin scattering, allowing the parametric amplifier to operate without modulating the pump. Internal fiber gain as high as 17.1 dB can be achieved with this configuration. View full abstract»

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  • Monte Carlo modeling of carrier transport and impact ionization in GaSb

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    An analytical band Monte Carlo (AMC) model has been developed to study the high field electron transport and the impact ionization in bulk gallium antimonide (GaSb). The AMC model uses three non-parabolic spherical valleys; in which Γ valley and L valley represent the first conduction band, while X valley represents the second conduction band. The scattering mechanisms included in this model are polar optical phonon, acoustic phonon, non-polar optical phonon (equivalent and non-equivalent intervalley), ionized impurity and impact ionization. The peak drift velocity occurs at 10 kV/cm and the saturation velocity is 8 × 104 m/s. Since the intervalley energy separation between the Γ valley and L valley is only 0.0847 eV, most electrons have already populated the higher valleys under small electric field. Thus, electrons in GaSb do not have sufficient time to acquire larger energy and lead to lower velocity before transfer to higher valley. This also leads to lower average electron energy for GaSb. The weak field dependence of GaSb at low field is attributed to majority of electrons impact ionising within the first conduction band. The impact ionization coefficient for GaSb is higher than that of InGaAs as GaSb has higher ionization rates. Besides that, GaSb has lower intervalley energy separation between the first and the second conductions, which leads to shorter average impact ionization path length and time. In addition, electrons in GaSb are able to impact ionise with higher average impact ionization energy as compare to InGaAs. View full abstract»

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  • Optimization Method for High Voltage Electro-Optic Shutter

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    Optimization Method for High Voltage Electro-Optic Devices is presented. Directions of improvement ways for typical engineering solutions are analyzed. Improvement directions including fastest operation, optical losses minimization, optical behaviors improvement, cost reducing, size and weight decreasing are considered. Modern Optical Arrangements of an Electro-Optic Shutter Schematic are compared. Different schematic designs of Q-Switch Drivers for Pockels Cell are presented. Computer Simulation of High Voltage Power supply is performed. Different schematic solutions of Q-Switch driver design are analyzed. High Voltage Step-up Transformer, Marx Bank based Generator and High Voltage Switch Schematics are compared. Parameters of constructed based on presented optimization method Q-Switch Drivers are given. View full abstract»

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  • Architecture of 3D laser TV system

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    A history of 3D laser TV system development is presented. Different types of an optical architecture for 2D and 3D laser TV are considered. Methods of optimization optical structure for application in laser television are described. Different existing optical simulation programs are compared. A program for calculation optical architecture with improved parameters is offered. To form stereo image based on principle of polarization separation, the optical arrangement including Faraday magneto- optical rotator is offered by authors. Especially for the presented system the projection lens with diffraction limited image quality was developed and manufactured. Proposal of further development of the system is given. View full abstract»

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  • Study on thermal behaviour of LED package at various ambient temperatures

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    Study on thermal behaviour for a Light-Emitting Diode (LED) package under different ambient temperatures was presented in this paper. Thermal transient measurements were carried out by using the Thermal Transient Tester (T3Ster) at each ambient temperature of 30°C, 50°C, 70°C, and 90°C T3Ster-Master evaluation software was adopted to analyze the recorded thermal transient structure function. Experimental results show that as the ambient temperature increases, the junction-to-ambient thermal resistance, RthJA an LED package will increase. View full abstract»

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  • Fabrication and characterization of Flat Fibers

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    This paper reports the fabrication and preliminary characterization of optical Flat Fibers. Unlike normal optical fibers which are basically cylindrical waveguides, Flat Fibers are ribbon-like planar samples, opening the possibility of extended length, fully flexible substrates. The fabrication of the Flat Fiber is performed by applying vacuum to a hollow silica preform during the fiber drawing process. Different vacuum settings are used in order to determine the optimum conditions. Other parameters that affect the fiber drawing process are preform feed speed and fiber drawing speed. Preliminary geometrical characterization results confirmed that the experiment (as a proof of principle) successfully produced Flat Fibers. Future work includes more detailed characterization such as determining the optical, mechanical and transmission characteristics of the Flat Fiber. View full abstract»

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  • Thermal resistance comparison of high power infrared emitter

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    This paper focuses on thermal characterization of high power infrared (IR) emitter. Thermal transient method is used to measure the junction temperature and calculate the thermal resistance (Rth). The emphasis is placed upon the investigation of thermal resistance value of units from different production lots at room temperature (25°C ± 0.5°C) for a limited range of input current (500mA, 800mA and 1A) with the air velocity kept constant throughout the experiment All investigations are based on the transient junction temperature measurements performed during the cooling process. The presented results include the cumulative structure functions and differential structure functions. It was found that the thermal resistance value of each unit differs from each other but the differences are minimal, proving the units are very consistent. View full abstract»

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