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Quantum Electronics, IEEE Journal of

Issue 12 • Date Dec. 2010

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Displaying Results 1 - 25 of 38
  • [Front cover]

    Publication Year: 2010 , Page(s): C1
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  • IEEE Journal of Quantum Electronics publication information

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

    Publication Year: 2010 , Page(s): 1687 - 1688
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  • Growth and Characteristics of Yb-doped {\rm Y}_{3}{\rm Ga}_{5}{\rm O}_{12} Laser Crystal

    Publication Year: 2010 , Page(s): 1689 - 1695
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (467 KB) |  | HTML iconHTML  

    Ytterbium (Yb) doped rare-earth garnet Y3Ga5O12 (YGG) single crystal was grown by the optical floating zone method for the first time, to our knowledge. Its structure and cell parameter were determined by X-ray powder diffraction. The thermal properties of Yb:YGG, including specific heat, thermal expansion coefficient, thermal diffusion coefficient, and thermal conductivity, were investigated. The optical properties of the crystal were also studied and the effective gain cross sections were calculated. With the crystal cut along the 〈111〉 direction, laser performance was also demonstrated by using a laser diode as the pump source. All the results show that Yb:YGG can be an excellent laser medium for applications to tunable and ultrafast pulsed lasers. View full abstract»

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  • Cross-Gain Modulation in Quantum-Dot SOA at 1550 nm

    Publication Year: 2010 , Page(s): 1696 - 1703
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (842 KB) |  | HTML iconHTML  

    We experimentally study the cross-gain modulation (XGM) in an InAs/InGaAsP/InP columnar quantum-dot semiconductor optical amplifier working in the 1550-nm spectral region. We report 12-nm wavelength conversion of 10, 20, 40, 80, and 160 Gb/s return-to-zero (RZ) signals. We find that pure XGM is effective for wavelength conversion without significant pattern effects up to around 40 Gb/s. At higher bit rates, distortion-free conversion can be obtained by exploiting jointly XGM and some cross-phase modulation that arises at the same time in the amplifier. This can be easily achieved by using a slightly blue-shifted output band-pass filter. By testing the signal integrity by means of the factor analysis, we also find that the XGM transfer function attenuates the input intensity noise. Finally, we show how the output inverse-RZ signals obtained in the XGM conversion can be format-converted back to RZ by side-band filtering. View full abstract»

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  • Photovoltaic MWIR Type-II Superlattice Focal Plane Array on GaAs Substrate

    Publication Year: 2010 , Page(s): 1704 - 1708
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (563 KB) |  | HTML iconHTML  

    Recent improvements in the performance of type-II superlattice (T2SL) photodetectors has spurred interest in developing low-cost and large-format focal plane arrays (FPAs) on this material system. Due to the limitations of size and cost of native GaSb substrates, GaAs is an attractive alternative with 8 in wafers commercially available, but is 7.8% lattice mismatched to T2SL. In this paper, we present a photovoltaic T2SL 320 × 256 FPA in the mid-wavelength infrared on GaAs substrate. The FPA attained a median noise equivalent temperature difference of 13 and 10 mK (F# = 2.3) with integration times of 10.02 and 19.06 ms, respectively, at 67 K. View full abstract»

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  • Resonant Power Coupling in Asynchronous Microring-Assisted Directional Couplers

    Publication Year: 2010 , Page(s): 1709 - 1716
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    Resonant power exchange process in asynchronous microring-assisted directional couplers (MRDCs) is proposed as a new approach for achieving complete power coupling between dissimilar waveguides. Theoretical analysis based on the coupled mode theory and verified by finite difference time domain simulations shows that complete cross power transfer between the two bus waveguides of an MRDC can be obtained near the microring resonances. Moreover, this power exchange occurs over a much shorter coupling length than existing techniques such as grating-assisted couplers and adiabatic taper couplers. These asynchronous MRDC structures are also characterized by spectral responses with steep transition slopes, suggesting new device possibilities for applications such as power couplers, switches, modulators, and optical sensors. View full abstract»

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  • Saturated Absorption Effects in CW-Pumped Solid-State Lasers

    Publication Year: 2010 , Page(s): 1717 - 1725
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (956 KB) |  | HTML iconHTML  

    Saturation effects in solid-state laser materials are important to accurately model and optimize the performance of laser devices. In this paper, we present analytical and numerical results describing the absorption in continuous wave solid-state lasers with both pump and laser saturation included, for flat-topped and Gaussian spatial distributions. Generalized absorption results are presented as a function of the ratio of pump intensity to pump saturation intensity, laser intensity to laser saturation intensity, optical thickness, and different ratios of laser to pump waists for collimated beams. These results apply to most solid-state laser energy level systems. View full abstract»

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  • Distortion-Free Single-Prism/Grating Ultrashort Laser Pulse Compressor

    Publication Year: 2010 , Page(s): 1726 - 1731
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (633 KB) |  | HTML iconHTML  

    We introduce an ultrashort laser pulse compressor that uses a single-prism and a single-grating. It is compact and automatically aligned and compensates for significant second- and third-order material dispersion. This design inherently has unity beam magnification and automatically contributes zero spatiotemporal distortions to the pulse, thus avoiding spatial chirp, angular dispersion, pulse-front tilt, and all other first-order spatiotemporal distortions common to pulse compressors. It is comprised of only four elements: a prism, a diffraction grating, a corner cube, and a roof mirror. It can provide large amounts of negative group-delay dispersion with small translations of the corner cube. Unlike conventional compressors, the device can operate on pulses with both large and small bandwidths by varying the corner cube position. Using this compressor, we demonstrate compensation of 12 m of optical fiber for 800-nm pulses with 30 nm of bandwidth. View full abstract»

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  • Impact of Self-Phase Modulation on Instabilities in Fiber Lasers

    Publication Year: 2010 , Page(s): 1732 - 1738
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1603 KB) |  | HTML iconHTML  

    Continuously pumped Yb-doped double-clad fiber lasers exhibit two kinds of instabilities, known as self-sustained pulsing and self-mode locking (SML). We study numerically the role of self-phase modulation (SPM) on the onset of these stabilities by using a spatiotemporal model that takes into account fully the length dependence of both the optical gain and spontaneous emission, while also including the nonlinear effects within the fiber. Self-sustained pulsations originate from relaxation oscillations. Although they die out quickly in the absence of SPM, our results show that SPM restores these oscillations when the laser power exceeds a certain value. SML has its origin in the spontaneous-emission noise acting as a seed. The laser cavity amplifies this noise the most at frequencies associated with its longitudinal modes, resulting in periodic power variations with an amplitude <; 1% (without SPM). We find that SPM plays again a critical role and increases their amplitude to above the 10% level. We also show that the SPM-induced instabilities can be suppressed by inserting a passive fiber of suitable length inside the laser cavity, which is in agreement with recent experimental work. View full abstract»

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  • Quantum Theory Analysis of Counterpropagating Twin Photon Generation by Parametric Downconversion

    Publication Year: 2010 , Page(s): 1739 - 1745
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (461 KB) |  | HTML iconHTML  

    Integrated nonlinear optical devices for the generation of twin photon beams are expected to be a key element for the development of quantum information techniques. This paper presents a quantum theory analysis of counterpropagating twin photon generation (CPTPG) by spontaneous parametric downconversion. Full descriptions of the quantum states of the twin photon beams having unique features are obtained in the Heisenberg and Schrödinger pictures. Mathematical expressions useful for device design and quantitative prediction of the performances, such as efficiency, wavelength spectrum and bandwidth, and photon correlation time, are deduced. Numerical data are given for specific quasi-phase-matched LiNbO3 waveguide CPTPG devices. View full abstract»

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  • Frequency-Dependent Complex Conductivities and Dielectric Responses of Indium Tin Oxide Thin Films From the Visible to the Far-Infrared

    Publication Year: 2010 , Page(s): 1746 - 1754
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (847 KB) |  | HTML iconHTML  

    Transparent and conducting indium tin oxide (ITO) thin films form an integral part for various optoelectronic devices. In this paper, we report the frequency-dependent complex conductivities and dielectric responses of several sputtered ITO thin films with thicknesses in the range of 189-962 nm by using terahertz time domain spectroscopy (THz-TDS), optical reflectance spectroscopy, and electrical measurements. The plasma frequencies are verified to be from 1590 to 1930 rad·THz, while the scattering times are in the range 6-7 fs based on the Drude free-electron model. The mobilities of the above ITO thin films are calculated to be 32.7-34.2 cm2 V-1 s-1, whereas the carrier concentrations lie in the range 2.79-4.10× 1020 cm-3. The electrical properties derived from the THz-TDS technique agree well with those determined by Hall measurement. Parameters for the complex dielectric function suitable for ITO in the range 0.2-2 and 4-450 THz are also determined. View full abstract»

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  • Large-Signal Response of Semiconductor Quantum-Dot Lasers

    Publication Year: 2010 , Page(s): 1755 - 1762
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1104 KB) |  | HTML iconHTML  

    In this paper, the large-signal response of a quantum-dot laser is investigated. Based on experimental results, we show that including a dynamic device temperature as well as Auger recombination processes in the carrier reservoir is crucial to model the dynamic response of a quantum-dot laser for large variations of the pump current. A detailed analysis of the influence of temperature effects on the dynamics of the device is performed. Simulated eye diagrams are presented and compared with experimental results at the emission wavelength of 1.3 μm. View full abstract»

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  • Optimization of Ion Implantation Condition for Depletion-Type Silicon Optical Modulators

    Publication Year: 2010 , Page(s): 1763 - 1768
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (414 KB) |  | HTML iconHTML  

    We study the influence of ion implantation conditions on the performance of depletion-type silicon optical modulators by a combined simulation of the process flow, the electrical characteristic, and the beam propagation. Through calculations using different implantation positions, energies, and tilt angles, this paper reveals that a gap between specific implantation windows is able to alleviate the modulation efficiency degradation due to the lateral straggling of implanted ions, while a tilt angle reduces the optical loss without harming the modulation efficiency. After an optimization of the implantation condition, the extinction ratio of the Mach-Zehnder modulator can be improved by 4.6 dB, while its optical loss falls from 3 to 2.47 dB. Finally, a simplified doping pattern that eliminates two implantation steps is discussed. View full abstract»

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  • Cylindrical Coordinates Coupled Mode Theory

    Publication Year: 2010 , Page(s): 1769 - 1774
    Cited by:  Papers (8)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (374 KB) |  | HTML iconHTML  

    We present a cylindrical coordinates coupled mode formulation for coupling between two degenerate modes of a traveling wave resonator. The resonator is assumed to have rotational symmetry and therefore two degenerate modes propagating in opposite directions. We analyze coupling of the resonance modes in space due to a perturbation in the resonator and derive first-order coupling equations. We also present an application of the method in modeling the mode coupling in a ring resonator with an integrated distributed Bragg reflector. For the presented structure, the results from coupled mode analysis agree with the finite elements method simulation results, and the method dramatically reduces the simulation time from 2 h to less than 5 min. View full abstract»

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  • Two-Photon Absorption and Spectral-Narrowed Light Source

    Publication Year: 2010 , Page(s): 1775 - 1781
    Cited by:  Papers (1)
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    This paper reports the two-photon absorption (TPA) and the spectral-narrowed light emission (SNLE) from the crystals of 9, 10-distyrylanthracene (DSA) derivatives. The results obtained by the Z-scan method show that the tested molecules possess high TPA cross sections. Upon near-IR excitation, strong two-photon-excited fluorescence could be observed in the crystals of four types of materials. Furthermore, SNLE with low threshold occurs in three of the four crystals under pumping with the second harmonic generated in the amplifier. Single crystals of the DSA derivatives exhibit unique photonic properties, including strong solid-state fluorescence, large TPA cross section, and stimulated emission. The results demonstrate that these are potential candidates for compact and practical solid-state laser applications. View full abstract»

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  • Strained Active Regions in GaAs-based Quantum Cascade Lasers

    Publication Year: 2010 , Page(s): 1782 - 1787
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (434 KB) |  | HTML iconHTML  

    This paper explores the effects of low indium concentration in deep-well AlGaAs/GaAs quantum cascade laser structures. Photon emission from these strained active regions involves nonlinear optical processes, which reduce the emission wavelength. Designs that incorporate strain in one and two wells of the active region, respectively, on (111) GaAs are compared. Results demonstrate wavelength extendibility in compressively strained deep-well GaAs-based devices. View full abstract»

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  • Dynamical Hysteresis and Thermal Effects in Vertical-Cavity Surface-Emitting Lasers

    Publication Year: 2010 , Page(s): 1788 - 1794
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (859 KB) |  | HTML iconHTML  

    We study numerically the polarization-resolved light-output characteristic of vertical-cavity surface-emitting lasers (VCSELs) using the spin-flip model for VCSELs extended to take into account thermal effects via a dynamical equation for the active region temperature, including heat dissipation, heating due to nonradiative carrier recombination, and Joule effect. The temperature dynamics is coupled to the carrier and optical field dynamics via a frequency and temperature-dependent gain coefficient. We show that the interplay of thermal effects and injection current variation can result in turn-on and turn-off hysteresis cycles that can be, depending on various model parameters, positive or negative. In the first case, the turn-on occurs at a higher value of the bias current than the turn-off; in a negative hysteresis cycle, the laser turns-on at a lower value of the bias current than the turn-off. These results are interpreted in terms of the interplay of the two time-scales determined by the injection current swept rate and the thermal relaxation rate. View full abstract»

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  • Efficient Pulse Compression Using Tapered Photonic Crystal Fiber at 850 nm

    Publication Year: 2010 , Page(s): 1795 - 1803
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (678 KB) |  | HTML iconHTML  

    By using appropriate self-similar scaling analysis, we delineate the generation of linearly chirped solitary pulses in photonic crystal fiber (PCF) at 850 nm to obtain the short pulses with large compression factor and minimal pedestal energy when compared to adiabatic compression scheme. The dispersion and nonlinearity varying nonlinear Schrödinger equation aptly models the pulse propagation in such a PCF. The analytical results demand that the effective dispersion must decrease exponentially while the nonlinearity must increase exponentially in the PCF. Thus, based on the analytical results, we propose the new design of tapered PCF by varying the pitch and diameter of the air hole. We adopt the projection operator method to derive the pulse parameter equations which indeed very clearly describe the self-similar pulse compression process at different parts of the PCF structures. As we are interested in constructing compact compressor, we also introduce another designing of PCF by filling chloroform in the core region. The chloroform filled tapered PCF exhibits low dispersion length for efficient pulse compression with low input pulse energy over small propagation distances. View full abstract»

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  • Modeling of Mode-Locked Coupled-Resonator Optical Waveguide Lasers

    Publication Year: 2010 , Page(s): 1804 - 1812
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (702 KB) |  | HTML iconHTML  

    Coupled-resonator optical waveguides made from coupled high- Q photonic crystal nanocavities are investigated for use as cavities in mode-locked lasers. Such devices show great potential in slowing down light and can serve to reduce the cavity length of a mode-locked laser. An explicit expression for the cold-cavity transmission spectrum is derived and used to interpret numerical investigations performed to characterize the parameter regime of active mode-locked operation. It is found that the modulation frequency relative to the centerband nearest supermode (SM) frequency shift determines the quality of the emerging pulse train. A range of tuning around this frequency allows for effective mode locking. Finally, noise is added to the generalized single-cavity eigenfrequencies in order to evaluate the effects of fabrication imperfections on the cold-cavity transmission properties and consequently on the locking of SMs. View full abstract»

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  • Strain-Balanced {\rm Ge}_{z}{\rm Sn}_{1-z}\hbox {--}{\rm Si}_{x}{\rm Ge}_{y}{\rm Sn}_{1-x-y} Multiple-Quantum-Well Lasers

    Publication Year: 2010 , Page(s): 1813 - 1820
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (650 KB) |  | HTML iconHTML  

    We propose and analyze a strain-balanced GezSn1-z-SixGeySn1-x-y multiple-quantum-well (MQW) laser. By incorporating a proper amount of -Sn into Ge, a direct-bandgap GeSn alloy can be realized to achieve population inversion in the direct conduction band. The introduction of compressive strain into the GeSn QW can effectively modify the valence band structure to reduce the threshold carrier density. We calculate the electronic band structure and the polarization-dependent optical gain of the strained GezSn1-z-SixGeySn1-x-y MQW laser taking into account the effect of the L-conduction bands. We also present our waveguide design for index guidance and calculate the optical confinement factors of various regions. Our calculation indicates that the modal gain can reach the threshold condition and lead to lasing action. View full abstract»

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  • Synchronization of Chaotic Fiber Lasers With Reduced External Coupling

    Publication Year: 2010 , Page(s): 1821 - 1826
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    In order to achieve synchronization between chaotic lasers the coupling strength must typically exceed a certain threshold. Here, we show how this threshold can be significantly reduced by adding loss that is minimized when the coupled lasers are both phase locked and synchronized. A model is developed for this loss enhanced synchronization and the calculated results are in good agreement to those obtained experimentally with two coupled chaotic fiber lasers. View full abstract»

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  • Patterned Quantum Dot Molecule Laser Fabricated by Electron Beam Lithography and Wet Chemical Etching

    Publication Year: 2010 , Page(s): 1827 - 1833
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (332 KB) |  | HTML iconHTML  

    We report on the fabrication and characterization of an edge-emitting semiconductor laser with a gain medium consisting of two layers of patterned, self-aligned, vertically coupled quantum dots (QDs) using a wet-etching and regrowth technique. A threshold current density of 300 A/cm2 is demonstrated at 77 K. The presence of emission from QD excited states in both the spontaneous emission and laser spectra indicates 3-D quantum confinement in QDs fabricated using this technique. View full abstract»

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  • AlGaInP LEDs Prepared by Contact-Transferred and Mask-Embedded Lithography

    Publication Year: 2010 , Page(s): 1834 - 1839
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (742 KB) |  | HTML iconHTML  

    The authors applied a simple, low-cost, mass-producible contact-transferred and mask-embedded lithography (CMEL) to texture p-GaP window layer for the fabrication of AlGaInP light-emitting diodes (LEDs) emitting at 612 nm. Under 20 mA current injection, it was found that forward voltages were 2.25, 2.39, 2.29, 2.39, 2.24, 2.21, and 2.25-V while the 20 mA output powers were 1.43, 1.42, 1.38, 1.35, 1.28, 1.22, and 1.16 mW for CMEL-400-nm LED, CMEL-600-nm LED, CMEL-800-nm LED, CMEL-1-μm LED, CMEL-2-μm LED, CMEL-3-μm, and the conventional LED without CMEL, respectively. View full abstract»

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  • Chaos Generation and Synchronization Using an Integrated Source With an Air Gap

    Publication Year: 2010 , Page(s): 1840 - 1846
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (961 KB) |  | HTML iconHTML  

    We discuss experimentally and numerically the dynamical behavior of a novel integrated semiconductor laser subject to multiple optical feedback loops. The laser's structure consists of distributed feedback section coupled to a waveguide, an air gap section and two phase sections. It is found that the laser, due to the multiple feedback loops and under certain operating conditions, displays chaotic behaviors appropriate for chaos-based communications. The synchronization properties of two unidirectionally coupled (master-slave) systems are also studied. Finally, we find numerically the conditions for message encryption/extraction using the multiple-feedback lasers. View full abstract»

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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..

Full Aims & Scope

Meet Our Editors

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