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Quantum Electronics, IEEE Journal of

Issue 5 • Date May 2007

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Displaying Results 1 - 14 of 14
  • [Front cover]

    Publication Year: 2007 , Page(s): C1
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  • IEEE Journal of Quantum Electronics publication information

    Publication Year: 2007 , Page(s): C2
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  • Table of contents

    Publication Year: 2007 , Page(s): 361 - 362
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  • Analysis of the Linewidth-Enhancement Factor of Long-Wavelength Tunnel-Injection Quantum-Dot Lasers

    Publication Year: 2007 , Page(s): 363 - 369
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (452 KB) |  | HTML iconHTML  

    We have studied the linewidth-enhancement factor of 1.3-mum tunnel-injection quantum-dot (QD) lasers utilizing a rate-equation model that takes into account the injection of electrons directly into the QDs from a coupled quantum well, the presence of wetting layer states, and nonequilibrium carrier relaxation in the QDs. In a conventional separate confinement heterostructure QD laser, plasma effects, which result from a large portion of the injected carriers preferably occupying the barrier and wetting layer states, largely determine the values of the linewidth-enhancement factor and lead to a strong dependence of the linewidth-enhancement factor on injection current. In a tunnel-injection QD laser, however, due to the injection of "cold" electrons directly into the lasing states of the QDs, both the values of linewidth-enhancement factor and the dependence on injection current are substantially reduced. The calculated linewidth-enhancement factors of conventional separate confinement heterostructure and tunnel-injection QD lasers are in excellent agreement with reported experimental values. Our analysis elucidates the role of tunnel injection in achieving near-zero alpha-parameter, which would be important in the design of chirp-free high-speed QD lasers View full abstract»

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  • Relative Intensity Noise Performance of Wavelength Converters Based on Four-Wave Mixing in Semiconductor Optical Amplifiers

    Publication Year: 2007 , Page(s): 370 - 377
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (546 KB) |  | HTML iconHTML  

    We present a numerical and experimental study of the relative intensity noise (RIN) induced by the four-wave mixing (FWM) based wavelength conversion process in a semiconductor optical amplifier (SOA). The study is based on the RIN evaluation of the converted signal, under various operating conditions (input power levels and wavelength detuning) and input noise characteristics. A detailed numerical model is employed to simulate the FWM process, taking into account the amplified spontaneous emission (ASE) noise, the wavelength dependent gain, and the interaction of four waves in the SOA (two input waves and two product waves). It is shown that for low noise input signals, the output RIN is determined by the power levels of the pump and signal and the wavelength detuning. Operation under saturation allows reduction of the output RIN levels with respect to the input View full abstract»

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  • Fundamental Thermal Noise in Distributed Feedback Fiber Lasers

    Publication Year: 2007 , Page(s): 378 - 384
    Cited by:  Papers (7)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (225 KB) |  | HTML iconHTML  

    A detailed analysis of fundamental thermal frequency noise in distributed feedback fiber lasers (DFB FL) is presented. An expression relating the laser frequency noise spectrum to the spectrum of thermal (temperature) fluctuations in the fiber, accounting for the nontrivial DFB FL mode shape, is derived. A new expression for the thermal fluctuation spectrum of single-mode optical fiber is derived which predicts high-frequency thermal noise 3 dB higher than previously published results. Theoretical predictions are compared against experimental measurements for a well characterized DFB FL. Anomalous 1/f noise at low frequency is discussed View full abstract»

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  • High-Power Laser Performance of Yb:YAl3(BO3)4 Crystals Cut Along the Crystallographic Axes

    Publication Year: 2007 , Page(s): 385 - 390
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (422 KB) |  | HTML iconHTML  

    High-power continuous-wave laser operation near 1 mum was demonstrated at room temperature with c-cut and a-cut Yb:YAl3(BO3)4 crystals end-pumped by a fiber-coupled diode laser. Using a 2-mm-thick c-cut crystal, 10.6 W of output power was generated with an optical-to-optical efficiency of 65% and a slope efficiency of 72%. The complex polarization state of the generated laser radiation was also studied. With a 2-mm-thick a-cut crystal, sigma-polarized laser oscillation was obtained, producing a maximum output power of 8.1 W; the optical-to-optical and slope efficiencies were 56% and 61%, respectively. Complete absorption and emission cross section spectra of the Yb:YAl3(BO3) 4 crystal were also derived, revealing very strong anisotropy of the spectroscopic properties View full abstract»

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  • Optical and Transport Characteristics of Quantum-Cascade Lasers With Optimized Second-Harmonic Generation

    Publication Year: 2007 , Page(s): 391 - 398
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (525 KB) |  | HTML iconHTML  

    We present simulations of midinfrared quantum-cascade lasers (QCLs) with optimized second-harmonic generation (SHG). The optimized design was obtained utilizing techniques from supersymmetric quantum mechanics with both material-dependent effective mass and band nonparabolicity. Carrier transport and power output of the structure are analyzed by self-consistently solving rate equations for the carriers and photons. Nonunity pumping efficiency from one period of the QCL to the next is taken into account by including all relevant electron-electron and electron-longitudinal (LO) phonon scattering mechanisms between the injector/collector and active regions. Two-photon absorption processes are analyzed for the resonant cascading triple levels designed for enhancing SHG. Both sequential and simultaneous two-photon absorptions are included in the rate-equation model. The current-output characteristics for both structures are analyzed and compared. Stronger resonant tunneling in the optimized structure is manifested by enhanced negative differential resistance. Current-dependent linear optical output power is derived based on the steady-state photon populations in the active region. The second-harmonic-power is derived from the Maxwell equations with the phase mismatch included. Due to stronger coupling between lasing levels, the optimized structure has both higher linear and nonlinear output powers. Phase mismatch effect is significant for both structures leading to a substantial reduction of the linear-to-nonlinear conversion efficiency. The optimized structure can be fabricated through digitally grading the submonolayer alloys by molecular beam epitaxy technique View full abstract»

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  • Comparison of Exactness of Scalar and Vectorial Optical Methods Used to Model a VCSEL Operation

    Publication Year: 2007 , Page(s): 399 - 406
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (484 KB) |  | HTML iconHTML  

    In the paper, a comparison between results of the optical scalar and vectorial optical methods, using the scalar effective frequency method and the vectorial method of lines, respectively, as their typical examples, applied for simulating an operation of vertical-cavity surface-emitting diode lasers (VCSELs) is presented. Both optical approaches has been applied to simulate an operation of the standard 1.3-mum GaAs-based oxide-confined GaInAsN double quantum-well VCSEL, but comparison conclusions seem to be more general and concerns all VCSELs. Validity limits of the simplified scalar approach have been determined by comparing its approximate results with more exact ones obtained with the aid of the accurate vectorial model. The scalar model has been found to be quite exact in the case of a determination of the wavelength of emitted radiation, whereas its exactness in the lasing threshold analysis is much worse, especially in the case of higher order modes, smaller aperture diameters and/or weak radial optical guidance. Our analysis leads also to more general designing conclusions concerning the optimal position and the thickness of the oxide layer assuring, respectively, the stable single mode operation and the lowest threshold gain View full abstract»

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  • Switchable Random Laser From Dye-Doped Polymer Dispersed Liquid Crystal Waveguides

    Publication Year: 2007 , Page(s): 407 - 410
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1259 KB) |  | HTML iconHTML  

    A dye-doped polymer-dispersed liquid crystal (PDLC) film has been fabricated for random lasing action. In this PDLC film, the sizes of most liquid crystal (LC) droplets ranged from 200 to 500 nm. When the sample is optically pumped, ultrahigh Q (>10 000) lasing modes and a collimated laser beam can be observed. The threshold of the random laser is shown to be 0.23 mJ/cm2. Additionally, a 9.2-V/mum external electric field was applied to control the orientations of LC molecules, thereby obtaining a switchable random laser. Consequently, the linewidth, intensity, and polarization of the emitted random laser are controlled View full abstract»

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  • Resonant-Cavity-Enhanced Far-Infrared Upconversion Imaging Devices

    Publication Year: 2007 , Page(s): 411 - 418
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (573 KB) |  | HTML iconHTML  

    We have carried out a detailed investigation on the application of resonant cavities to the photon-frequency-upconversion-based far-infrared (FIR) semiconductor imaging devices. The employment of a bottom mirror (BM) enhances the FIR photon absorption efficiency and, therefore, increases the quantum efficiency of GaAs homojunction interfacial work- function internal photoemission (HIWIP) FIR detectors. Significant improvement of the extraction efficiency could be achieved in resonant cavity enhanced (RCE) GaAs-AlGaAs near-infrared (NIR) light-emitting diodes (LEDs) through redirecting as many NIR photons as possible into the escape cone. Under the optimal structural parameters, we have predicted that the upconversion quantum efficiency of the integrated HIWIP-BM-RCE-LED imaging device could be boosted to 5-6 times of the normal HIWIP-LED upconverter without any resonant cavities. As a consequence of few reincarnation cycles needed by NIR photons to escape in the photon recycling process, we can further expect sharp and high-resolution imaging in HIWIP-BM-RCE-LED View full abstract»

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  • High-Order Split-Step Schemes for Time-Dependent Coupled-Wave Equations

    Publication Year: 2007 , Page(s): 419 - 425
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (519 KB) |  | HTML iconHTML  

    A high-order split-step algorithm is developed and presented to solve the time-dependent coupled-wave equations for traveling-wave optical fields in a variety of grating-based optical devices such as the distributed feedback and distributed Bragg reflector lasers. Based on the Suzuki's fractal decomposition approach, Lie-Trotter-Suzuki product formula is used to construct the higher order solution that converges faster than the conventional split-step method. The accuracy and efficiency of the new scheme are assessed by way of examples and shown to be superior to those of the conventional method View full abstract»

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  • RF-Interferences Generate Chaotic GHz FM—Carrier for Communications

    Publication Year: 2007 , Page(s): 426 - 433
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (868 KB) |  | HTML iconHTML  

    Following the principle of a highly nonlinear delay oscillator, we demonstrate the generation of an RF chaotic frequency modulated carrier, which could be used in chaos based communication systems. The nonlinear process is provided by the transfer function of an RF interferometer, modulating the amplitude of an FM signal; for this purpose, the path difference required for the interference process, as well as a long delay required for complex chaotic oscillation, are designed through the use of optical fibers. The RF signal used to produce interferences is transposed in the optical domain by a direct laser modulation with the gigahertz chaotic FM signal. The interference is obtained at fiber outputs terminated by photodiodes for backconversion of the RF signal into the electrical domain. Experimental results reporting the particular dynamical behavior of the nonlinear delay RF oscillator are presented, and also discussed in terms of chaos communication applications View full abstract»

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  • IEEE Journal of Quantum Electronics information for authors

    Publication Year: 2007 , Page(s): 434
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Aims & Scope

The IEEE Journal of Quantum Electronics is dedicated to the publication of manuscripts reporting novel experimental or theoretical results in the broad field of the science and technology of quantum electronics..

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Meet Our Editors

Editor-in-Chief
Aaron R. Hawkins
Brigham Young University