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Quantum Electronics, IEEE Journal of

Issue 11 • Date Nov. 2004

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Displaying Results 1 - 19 of 19
  • Table of contents

    Page(s): c1 - c4
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    Freely Available from IEEE
  • IEEE Journal of Quantum Electronics publication information

    Page(s): c2
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  • Saturation and noise properties of quantum-dot optical amplifiers

    Page(s): 1527 - 1539
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (448 KB) |  | HTML iconHTML  

    Based on extensive numerical calculations, quantum-dot (QD) amplifiers are predicted to offer higher output power and lower noise figure compared to bulk as well as quantum well amplifiers. The underlying physical mechanisms are analyzed in detail, leading to the identification of a few key requirements that QD amplifiers should meet in order to achieve such superior linear characteristics. The existence of a highly inverted wetting layer or barrier region, acting as a carrier reservoir, is central to this performance enhancement. It is shown that amplified spontaneous emission acts to decrease the inversion of the wetting layer states, thus helping to quench the gain of these states, which might otherwise dominate. View full abstract»

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  • Investigation of semiconductor optical amplifier integrated with DBR laser for high saturation power and fast gain dynamics

    Page(s): 1540 - 1547
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (336 KB) |  | HTML iconHTML  

    A detailed theoretical investigation of an integration of a semiconductor optical amplifier (SOA) and distributed Bragg reflector (DBR) laser is presented. The dependence of the device performance on those key design parameters such as the lasing wavelength, light injection direction (co- and contra-propagation), lasing power of the DBR laser, and the biasing condition of the SOA is examined systematically by means of a comprehensive time-domain traveling-wave model. As this integrated structure is particularly designed for high saturation power and fast gain dynamics, these characteristics are simulated and compared with the results from the conventional structures. Depending on different requirements, superior performance on either saturation power or noise figure without compromise on the optical gain can be achieved by different integration configurations (i.e., by different light injection directions). For the structure with the light injection from the output end of the SOA (namely, the integrated SOA-laser structure), the fast gain dynamics is found through simulation, which helps to reduce the large-signal waveform distortion in the amplification of narrow pulses. View full abstract»

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  • Wavelength conversions in quasi-phase matched LiNbO3 waveguide based on double-pass cascaded χ(2) SFG+DFG interactions

    Page(s): 1548 - 1554
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (488 KB) |  | HTML iconHTML  

    Based on the cascaded nonlinear interactions (χ(2)(2)) of sum- and difference-frequency generation (SFG+DFG), a novel all-optical wavelength conversion scheme is proposed for the first time in periodically poled LiNbO3 (PPLN) waveguide, in which a double-pass configuration is introduced. The performance of this scheme is thus different from the previous single-pass SFG+DFG scheme. The concept of the "balance condition" is presented to optimize the power and frequencies of the two pump sources. Under this condition, the energy is transferred irreversibly from the pump waves to the SF wave during the forward propagation. The equations describing the SFG can be solved analytically under this condition. Subsequently, the DFG equations are solved under the assumption that the SF wave would be constant during the backward propagation. Theoretical expressions are derived and are found to be consistent with numerical calculations. Compared with the conventional converter based on the cascaded χ(2)(2) interactions of second-harmonic generation and difference frequency generation SHG+DFG, the same conversion efficiency can be achieved in our scheme by employing two pump sources with lower power, or conversely higher conversion efficiency can be reached using two pump sources similar to that used in SFG+DFG scheme. The profile of the conversion efficiency can be further improved by adjusting the wavelengths of the two pump sources. In addition, compared with the single-pass SFG+DFG scheme, the main advantage of this new scheme rests on the fact that the conversion efficiency can be enhanced significantly. The advantages of the double-pass SHG+DFG scheme and the single-pass SFG+DFG scheme are combined in this new design to a great extent. View full abstract»

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  • Modeling of optical waveguide poling and thermally stimulated discharge (TSD) charge and current densities for guest/host electro-optic polymers

    Page(s): 1555 - 1561
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (304 KB) |  | HTML iconHTML  

    A charge density and current density model of a waveguide system has been developed to explore the effects of electric field electrode poling. An optical waveguide is modeled during poling by considering the dielectric charge distribution, polarization charge distribution, and conduction charge generated by the poling field. The charge distributions are the source of poling current densities. The model shows that boundary charge current density and polarization current density are the major source of currents measured during poling and thermally stimulated discharge measurements. Charge distributions provide insight into the poling mechanisms and are directly related to EA and αr. Initial comparisons with experimental data show excellent correlation to the model results. View full abstract»

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  • Analytical solutions for thermal stresses in buried channel waveguides

    Page(s): 1562 - 1568
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (392 KB) |  | HTML iconHTML  

    Thermal stresses are important factors in determining the birefringence of optical waveguides. Analytical solutions are developed to estimate the thermal stresses in the core of a buried rectangular channel waveguide. The closed-form solutions for various situations are obtained. The results show that the thermal expansion mismatch between the upper cladding and substrate plays significant role in determining the anisotropy of the thermal stresses in the core. The analytical solutions developed in this paper are consistent with finite element simulations and experimental results. View full abstract»

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  • Low misalignment sensitivity Kerr-lens mode-locked femtosecond Cr4+:Forsterite laser for nonlinear microscopy

    Page(s): 1569 - 1574
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1232 KB) |  | HTML iconHTML  

    We optimized a Kerr-lens mode-locked (KLM) femtosecond Cr4+:forsterite laser using a five-mirror cavity, taking advantage of its peculiar low misalignment sensitivity and using an effective KLM mapping technique. A simple scanning nonlinear microscope based on this laser source has been developed and second harmonic images of the layered structure of a microchip are presented. View full abstract»

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  • Optimization of Er, Yb:YCOB for CW laser operation

    Page(s): 1575 - 1582
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    The erbium and ytterbium ion concentrations in the host yttrium calcium oxaborate have been optimized for diode pumped continuous-wave (CW) laser operation using spectroscopic measurements, modeling of energy transfer and population rate equation analysis, resulting in 270 mW of CW output from a diode-pumped Er,Yb:YCOB laser. View full abstract»

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  • Switching-induced perturbation and influence on actively Q-switched fiber lasers

    Page(s): 1583 - 1596
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    Dynamic characteristics of typical actively Q-switched fiber lasers are numerically investigated by using the traveling-wave method. The multipeak phenomena of output pulses are analyzed, and the mechanism for these phenomena is detailed. In particular, the switching-induced perturbation and its influence are emphasized under different conditions. A quantitative analysis shows that under certain conditions of cavity, pump and switching, a split-pulse output can turn to a single-pulse output. Then how to realize the single-pulse output is systematically illustrated, and some experimental results are shown for comparison. View full abstract»

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  • Propagation of short pulses in an active nonlinear two-core optical fiber

    Page(s): 1597 - 1602
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    The switching dynamics of short pulses in an active nonlinear two-core fiber coupler is investigated theoretically. The analysis takes into account the effects of coupling-coefficient dispersion, gain bandwidth, and gain saturation. In particular, we demonstrate that the pulse breakup effect due to coupling-coefficient dispersion can be suppressed by limiting the bandwidth of the linear gain, whether gain saturation is considered or not. View full abstract»

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  • Re-investigation of optically pumped hydrazine far-infrared laser around 11 μm from the 10HP and 10P bands of a pulsed CO2 laser: new lines and assignments

    Page(s): 1603 - 1606
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (192 KB) |  | HTML iconHTML  

    A high-peak-power (several hundreds of watts) pulsed CO2 laser, recently developed in our laboratory, has been used for exciting optically pumped far-infrared laser transitions of N2H4. A systematic search for N2H4 absorption coincidences with 10P and 10HP CO2 laser emissions has led to the observation of 27 new far-infrared laser lines, excited by 18 different absorption transitions. All of these new lines have been characterized in wavelength, offset, relative polarization, optimum operation pressure and intensity. Using the LaseRitz program, ten of these lines were assigned, corresponding to five laser systems. For other two laser systems possible J and K quantum numbers of the energy levels involved in the laser transitions were given. View full abstract»

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  • Edge-coupled InGaAs PIN photodiode with a light funnel waveguide

    Page(s): 1607 - 1613
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    We have successfully fabricated InGaAs edge-coupled photodiodes (EC-PDs) with a light funnel integrated (LIFI) in front of the coupling aperture, called LIFI EC-PD, based on the self-terminated oxide polish (STOP), the crystallographic slope etching of InP, and the self-aligned diffusion (SAD) techniques. The LIFI EC-PD presents not only a lower dark current density (∼ 4.4 mA/cm2) but also a higher responsivity (∼ 0.4 A/W) than that of the mesa EC-PD (27 mA/cm2 and 0.26 A/W, respectively). Furthermore, the thick oxide film serves as the funnel in front of active-region aperture to enhance the coupling efficiency and to lower the bonding pad capacitance down to 50 fF. The lowered bonding pad capacitance can be beneficial in designing a device with a higher transit-time-limited frequency response of beyond 30 GHz. The LIFI EC-PD with a 1-μm thick absorption layer exhibits a 3-dB bandwidth of 20 GHz and a responsivity of ∼ 0.4 A/W. View full abstract»

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  • Dilute magnetic semiconductor quantum-well structures for magnetic field tunable far-infrared/terahertz absorption

    Page(s): 1614 - 1621
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    The design of ZnCdSe-ZnMnSe-based quantum wells is considered, in order to obtain a large shift of the peak absorption wavelength in the far infrared range, due to a giant Zeeman splitting with magnetic field, while maintaining a reasonably large value of peak absorption. A triple quantum-well structure with a suitable choice of parameters has been found to satisfy such requirements. A maximal tuning range between 14.6 and 34.7 meV is obtained, when the magnetic field varies from zero to 5 T, so the wavelength of the absorbed radiation decreases from 85.2 to 35.7 μm with absorption up to 1.25% at low temperatures. These structures might form the basis for magnetic field tunable photodetectors and quantum cascade lasers in the terahertz range. View full abstract»

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  • Dependence of transmission curves on input optical power in an electroabsorption modulator

    Page(s): 1622 - 1628
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    We present a novel method to extract the optical absorption coefficient of a semiconductor electroabsorption modulator (EAM) with antireflection coated facets. Only the transmission and photocurrent data are needed with this method. The method allows to obtain the total optical coupling loss, internal quantum efficiency, and optical absorption coefficients when input optical power is low. We also developed a method to analyze optical absorption coefficient with the saturation effect. By using those methods, we investigated the dependence of the transfer curves on the input optical power in a multiple-quantum-well EAM. The optical loss saturation effect and the increase of device temperature are the dominant mechanisms for the dependence of transfer curves on the input optical power in the low bias region and the high bias region, respectively. View full abstract»

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  • Special issue on biophotonics

    Page(s): 1630
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  • IEEE Journal of Quantum Electronics information for authors

    Page(s): c3
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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