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Quantum Electronics, IEEE Journal of

Issue 9 • Date Sept. 2006

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Displaying Results 1 - 18 of 18
  • Vertical-cavity surface-emitting lasers based on submonolayer InGaAs quantum dots

    Publication Year: 2006 , Page(s): 851 - 858
    Cited by:  Papers (8)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (492 KB) |  | HTML iconHTML  

    Molecular beam epitaxy-grown 0.98-mum vertical-cavity surface-emitting lasers (VCSELs) with a three-stack submonolayer (SML) InGaAs quantum-dot (QD) active region and fully doped AlxGa 1-xAs-GaAs DBRs was studied. Large-aperture VCSELs demonstrated internal optical losses less than 0.1% per one pass. Single-mode operation throughout the whole current range was observed for SML QD VCSELs with the tapered oxide apertures diameter less than 2 mum. Devices with 3-mum tapered-aperture showed high single-mode output power of 4 mW and external quantum efficiency of 68% at room temperature View full abstract»

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  • Investigation of thermal effects in quantum-cascade lasers

    Publication Year: 2006 , Page(s): 859 - 867
    Cited by:  Papers (20)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1436 KB) |  | HTML iconHTML  

    The development of a thermal model for quantum cascade lasers (QCLs) is presented. The model is used in conjunction with a self-consistent scattering rate calculation of the electron dynamics of an InGaAs-AlAsSb QCL to calculate the temperature distribution throughout the device which can be a limiting factor for high temperature operation. The model is used to investigate the effects of various driving conditions and device geometries, such as epilayer down bonding and buried heterostructures, on the active region temperature. It is found that buried heterostructures have a factor of eight decrease in thermal time constants compared to standard ridge waveguide structures in pulsed mode and allow a ~78% increase in heat sink temperature compared to epilayer down mounted devices in continuous-wave mode. The model presented provides a valuable tool for understanding the thermal dynamics inside a quantum cascade laser and will help to improve their operating temperatures View full abstract»

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  • Continuously wavelength-tunable MQW fabry-perot laser diode pulse source with a fiber-based external cavity

    Publication Year: 2006 , Page(s): 868 - 872
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (968 KB) |  | HTML iconHTML  

    A simple continuously wavelength-tunable fiber ring laser pulse source is demonstrated. Such a source employs a gain-switched multiple quantum-well Fabry-Perot laser diode in a self-seeding scheme and the output pulse wavelength can be tuned continuously via a tunable optical filter. The optical pulses generated exhibit a pulsewidth of 92 ps at the frequency of 2.6 GHz. Within a wide wavelength tuning range of 46 nm, the side-mode suppression ratio and the average power of the output optical pulses obtained are higher than 50.1 dB and 3.3 dBm, respectively, and the pulse spectral stability can be maintained in the whole wavelength tuning range View full abstract»

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  • Efficient picosecond pulse shaping by programmable Bragg gratings

    Publication Year: 2006 , Page(s): 873 - 884
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1832 KB) |  | HTML iconHTML  

    We propose an efficient approach for arbitrary optical pulse shaping in the subhundred to a few hundreds picosecond regime. The designed device uses one-dimensional wave-guided Bragg gratings filled with an electrically controlled dielectric. One hundred electrodes are attached along the waveguide so that the refractive index pattern is programmable by applying voltages. The frequency response of this device with certain refractive index patterns is analyzed. Numerical simulations show that output pulses with desired shapes and high efficiency (>40% of theoretical maximum) can be obtained by using a genetic algorithm searching method augmented by an adiabatic following optimization scheme View full abstract»

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  • Optical field concentration in low-index waveguides

    Publication Year: 2006 , Page(s): 885 - 890
    Cited by:  Papers (18)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1152 KB) |  | HTML iconHTML  

    We present a highly efficient optical field concentrator that is capable of confining optical field in nanometer-thin low-index media with very high optical confinement factor. The structure is made of multiple-layered low-index nanolayers embedded in high-index silicon waveguides. By creating multiple high-index-contrast interfaces, the normal field in the low-index nanolayer regions is significantly enhanced. It subsequently results in a very high optical confinement and power density in these regions. With the help of numerical simulation tools, the guiding and propagating characteristics of the new structure are studied and presented. The optimal structures have demonstrated confinement factors and normalized power densities in the range of 30%-60% and 20-160 mum-2 for the 5-20-nm thin low-index multiple nanolayers View full abstract»

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  • Threshold analysis of vertical-cavity surface-emitting lasers with intracavity contacts

    Publication Year: 2006 , Page(s): 891 - 897
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (593 KB) |  | HTML iconHTML  

    A numerical analysis of vertical-cavity surface-emitting lasers (VCSELs) incorporating intracavity contacts and distributed Bragg reflectors (DBRs) is presented. The model considers polarization dependent reflection at the DBRs, current spreading, and nonuniform carrier density distribution self consistently. Analytic expressions for the current spreading and the corresponding series resistance for VCSELs incorporating intracavity contacts are derived. It is shown that current spreading strongly affects the lateral gain profile, the threshold current density, the transverse mode shape and the transverse mode discrimination through the creation of intracavity optical phase and gain apertures. The series resistance and the depth of the dip in the current density distribution are used as figures-of-merit to provide guidelines for device optimization, as illustrated by means of two examples of long wavelength VCSEL designs View full abstract»

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  • The effects of stress, temperature, and spin flips on polarization switching in vertical-cavity surface-emitting lasers

    Publication Year: 2006 , Page(s): 898 - 906
    Cited by:  Papers (9)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1281 KB) |  | HTML iconHTML  

    We discuss the effect of uniaxial planar stress on polarization switching in vertical-cavity surface-emitting lasers (VCSELs). The approach is based on an explicit form of a frequency-dependent complex susceptibility of the uniaxially stressed quantum-well semiconductor material. In this mesoscopic framework, we have taken cavity anisotropies, spin carrier dynamics, and thermal shift of the gain curve into account. In this way, we present a model that provides a global overview of the polarization switching phenomenon. The results are compared with experiments on an air-post VCSEL operating at 980 nm View full abstract»

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  • 3.77-5.05-μm tunable solid-state lasers based on Fe/sup 2+/-doped ZnSe crystals operating at low and room temperatures

    Publication Year: 2006 , Page(s): 907 - 917
    Cited by:  Papers (21)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1088 KB) |  | HTML iconHTML  

    Spectroscopic properties and lasing of Fe:ZnSe and co-doped Fe:Cr:ZnSe crystals in the mid-infrared spectral range were studied at room and low temperatures. Using a free-running Er:YAG laser as a pump source, the output energy of the thermoelectrically cooled Fe:ZnSe laser was 142 mJ with 30% slope efficiency at T=220 K. Passive Q-switched oscillation of Er:YAG laser with Fe:ZnSe crystal was demonstrated and used as a pump source for a Fe:ZnSe laser system. Room-temperature (RT) gain-switched lasing of Fe:ZnSe was achieved in microchip and selective cavity configurations using Q-switched Er:YAG and Raman-shifted Nd:YAG lasers as pump sources. The microchip laser threshold of 100 mJ/cm2 was demonstrated using a Fe:ZnSe crystal without any reflection coatings. A slope efficiency of 13%, oscillation threshold of 1.3 mJ, and tunable oscillation of Fe:ZnSe laser systems over 3.95-5.05 mum spectral range were realized at RT View full abstract»

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  • Additive noise and jitter performance analysis of passive optical interferometers operated at ultrahigh rates

    Publication Year: 2006 , Page(s): 918 - 926
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (264 KB) |  | HTML iconHTML  

    In this paper, we theoretically associate the additive noise, the amplitude jitter and the timing jitter at the input and output of passive optical interferometers. We make use of the theoretical results to assess the noise and jitter performance of interferometer based applications such as pulse repetition frequency multiplication and clock recovery. We show that, for both applications, interferometers may successfully reduce the noise and the jitter existing in the input signals, and thus yield very high quality output signals. Furthermore, we focus on the practical aspects of deploying Fabry-Peacuterot interferometers in rate multipliers and clock recoveries, and provide rules for selecting the characteristics of the Fabry-Peacuterot interferometer to meet specific quality requirements for the output signal View full abstract»

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  • Theoretical and experimental study on the self-Raman laser with Nd:YVO/sub 4/ crystal

    Publication Year: 2006 , Page(s): 927 - 933
    Cited by:  Papers (14)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (350 KB) |  | HTML iconHTML  

    The intracavity photon densities and the initial population inversion density were assumed to be Gaussian distributions in the rate equations of the laser diode end-pumped actively Q-switched intracavity Raman laser. These space-dependent rate equations were solved numerically. In the experiment, an efficient self-Raman laser was realized based on the multifunctional Nd:YVO4 laser crystal with the acoustooptic Q-switch. The output, temporal, and spectral characteristics of the self-Raman laser were investigated experimentally in detail. The performance of the self-Raman laser was studied numerically, and the theoretical results showed the main trends of the intracavity Raman laser, which are in agreement with the experimental ones View full abstract»

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  • Numerical simulation of intensity and phase noise from extracted parameters for CW DFB lasers

    Publication Year: 2006 , Page(s): 934 - 941
    Cited by:  Papers (13)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (674 KB) |  | HTML iconHTML  

    A self-consistent numerical approach is demonstrated to analyze intensity and phase noise from experimentally extracted parameters for a continuous-wave distributed feedback (DFB) laser. The approach takes into account the intrinsic fluctuations of the photon number, carrier number, and phase. Values for the parameters appearing in the rate equations are extracted from the measured relative intensity noise spectra and linewidth of the laser. The simulation of the frequency spectra of intensity and phase noise of the DFB laser are performed by fast Fourier transform and exhibit good agreement with experimental results. The model presented here can readily be extended for the purpose of system simulations View full abstract»

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  • Theoretical and experimental study of optical gain, refractive index change, and linewidth enhancement factor of p-doped quantum-dot lasers

    Publication Year: 2006 , Page(s): 942 - 952
    Cited by:  Papers (16)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (534 KB) |  | HTML iconHTML  

    A theoretical and experimental study of the optical gain, refractive index change, and linewidth enhancement factor (LEF) of a p-doped quantum-dot (QD) laser is reported. These parameters are measured by injecting an external pump, which induces cross-gain and cross-phase modulation. A comprehensive theoretical model for the optical gain and refractive index change of InAs QD lasers is introduced with the quasi-equilibrium approximation of carrier distribution. We use the Gaussian lineshape function for gain change and the confluent hypergeometric function of the first kind for refractive index change, which satisfies the Kramers-Kronig relation. We match the experimental data with the theoretical results when the thermal effect is isolated by an additional pulsed current measurement. We also calculate theoretically the optical gain, refractive index change, and LEF of an undoped QD laser of the same structure except the absence of p-type doping. We show that the differential gain and LEF of the p-doped QD laser are improved compared with those of the undoped QD laser due to the reduced transparency carrier density View full abstract»

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  • Mismatch robustness and security of chaotic optical communications based on injection-locking chaos synchronization

    Publication Year: 2006 , Page(s): 953 - 960
    Cited by:  Papers (29)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (961 KB) |  | HTML iconHTML  

    Mismatch robustness and its effects on security of chaotic optical communication system based on injection-locking chaos synchronization are studied numerically by establishing the corresponding SIMULINK model. Unlike previous studies, we focus on the communication relating issues when parameter mismatches are considered. The mismatch robustness of generalized synchronization is discussed firstly in terms of cross-correlation coefficient and synchronization error. Decoding performances as well as the effects of message strength are examined for both with and without mismatch cases. Effects of injection strength on system decoding performances are also investigated by examining the chaos-pass filtering effect. Finally, a modified decoding scheme is brought forward to improve the system decoding capability. Results show that the system under consideration exhibits unconspicuous difference in both synchronization and decoding characteristics when large parameter mismatches are considered. The system based on injection-locking chaos synchronization is inappropriate for the applications where high transmission security is necessary View full abstract»

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  • Large anomalous dispersion at short wavelength and modal properties of a photonic crystal fiber with large air holes

    Publication Year: 2006 , Page(s): 961 - 968
    Cited by:  Papers (6)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (623 KB) |  | HTML iconHTML  

    We investigated the dispersion and modal properties of a photonic crystal fiber (PCF) with larger air holes (LAH). The theoretical and numerical results show that large anomalous group-velocity dispersion at short wavelength down to around 700 ~ 800 nm can be achieved in a LAH-PCF with small pitch. Furthermore, the high-order modes usually are excited in a LAH-PCF when the optical field is launched from a traditional single-mode fiber, and all the excited modes will interfere when they propagate along the PCF. Finally, the properties of the excited modal spectrum and the multimode interference are determined by the normalized pitch and the normalized hole size of the PCF. All of these will provide references for the smoothing applications of the LAH-PCF View full abstract»

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  • Table of contents

    Publication Year: 2006 , Page(s): 969 - 970
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    Freely Available from IEEE
  • [Front cover]

    Publication Year: 2006 , Page(s): 971
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    Freely Available from IEEE
  • IEEE Journal of Quantum Electronics publication information

    Publication Year: 2006 , Page(s): 972
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    Freely Available from IEEE
  • IEEE Journal of Quantum Electronics information for authors

    Publication Year: 2006 , Page(s): 973
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    Freely Available from IEEE

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