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  • 1
    Electronic Resource
    Electronic Resource
    Theoretical analysis of gain saturation coefficients in InP-based strained-layer quantum-well lasers (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 2971-2973 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The gain saturation coefficients of tensile-strained, lattice-matched, and compressive-strained InGaAs/InGaAsP quantum-well lasers (QWLs) are calculated from intrasubband relaxation times. The intrasubband relaxation times are in turn obtained within the random-phase approximation including carrier–carrier and carrier–polar-optical phonon interactions at room temperature. The effects of strain on the band structures are included by taking into account the strain-dependent coupling among heavy-hole, light-hole, and spin-orbit split-off subbands on the basis of the multiband effective-mass theory. It is demonstrated that the gain saturation coefficient in tensile-strained QWLs is less sensitive to the amount of strain than in compressive-strained QWLs where it markedly increases with strain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354607
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  • 2
    Electronic Resource
    Electronic Resource
    Strain and quantum-confinement effects on differential gain of strained InGaAsP/InP quantum well lasers (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 4242-4244 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The effects of both strain and quantum confinement on the differential gain of strained InGaAsP/InP quantum well lasers (QWLs) are studied on the basis of valence-band structures calculated by k⋅p theory. Using an InGaAsP quaternary compound as an active layer makes it possible to separate the effect of strain (both tensile and compressive) from the quantum-confinement effect. In tensile-strained quantum wells, both strain and quantum-confinement effects exert a significant influence not only on the valence-band density of states (DOS) but also on the valence-subband energy spacings. In compressive-strained wells, on the other hand, the strain and quantum-confinement effects play an independent role in determining the DOS and the subband energy spacings, respectively. On the basis of these characteristic features of the valence-band structure of strained quantum wells, we discuss basic design principles for strained QWLs with larger differential gain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354432
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  • 3
    Electronic Resource
    Electronic Resource
    Two-dimensional numerical analysis of current blocking mechanism in InP buried heterostructure lasers (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 3572-3578 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The current blocking mechanism in InP buried heterostructure (BH) lasers is analyzed with a self-consistent, two-dimensional numerical analysis method. It has been clarified that quasi-Fermi potentials which are kept constant in the active region under lasing oscillation play a key role in determining the current blocking capability. Due to this potential pinning effect, the junction voltages at each constituent p-n junction in the blocking regions are maintained lower than the electrical turn-on voltage, which realizes an excellent current blocking in BH lasers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350913
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  • 4
    Electronic Resource
    Electronic Resource
    Temperature dependence of intrasubband relaxation time and its influence on high-temperature characteristics of InP-based quantum-well lasers (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 5237-5240 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: By taking into account the temperature dependence of the intrasubband relaxation times for electrons and holes, we study the temperature sensitivity of the optical gain and of the gain saturation coefficient for 1.3-μm InP-based strained-layer (SL) quantum-well (QW) lasers. The band structures are obtained by the self-consistent numerical solution of the Poisson equation, the scalar effective-mass equation for the conduction band, and the multiband effective-mass equation for the valence band. The intrasubband relaxation times are then calculated within the fully dynamic random phase approximation including carrier-carrier and carrier-phonon interactions on an equal basis. We demonstrate that the temperature dependence of the intrasubband relaxation times plays a key role in determining the temperature sensitivity of the optical gain and of the gain saturation coefficient of InP-based SL-QW lasers. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359274
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  • 5
    Electronic Resource
    Electronic Resource
    Electrostatic deformation in band profiles of InP-based strained-layer quantum-well lasers (1995)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 5180-5184 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We study the electrostatic deformation in the conduction-band and valence-band profiles of 1.3-μm InP-based strained-layer (SL) quantum-well (QW) lasers in the temperature range of 273–373 K. Electrostatic deformation is analyzed by the self-consistent numerical solution of the Poisson's equation, the scalar effective-mass equation for the conduction band, and the multiband effective-mass equation for the valence band. It is shown that, in InP-based QWs, electrostatic band-profile deformation causes a significant change in effective barrier height for the conduction and valence bands, which has a pronounced influence on the electron and hole distribution throughout the whole QW structure in the temperature range studied. We demonstrate that it is necessary to take into account electrostatic deformation in both band profiles for an analysis of the high-temperature characteristics of InP-based SL-QW lasers. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.359265
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  • 6
    Electronic Resource
    Electronic Resource
    The effects of strain on the threshold current density in InGaAsP/InP strained-layer single-quantum-well lasers (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 3250-3254 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Basic design principles are formulated for minimizing the threshold current density in InGaAsP/InP strained-layer single-quantum-well (SL-SQW) lasers. A quaternary InGaAsP active layer is shown to provide more freedom in design than a ternary InGaAs active layer because the amount of strain (both tension and compression) and quantum-well thickness can be independently determined in the InGaAsP system for a given emission wavelength. Strain-induced changes in the valence-band structures are analyzed within the framework of k⋅p theory by taking into account the interaction with spin-orbit split-off bands as well as heavy-hole and light-hole bands. It is clarified that the quantum-well thickness plays a more significant role than the amount of strain when designing compressive-strained wells, while the situation is just the opposite in tensile-strained wells. It is shown that, although the application of biaxial tension reduces the threshold current density in bulk-like SL-SQW lasers more significantly than biaxial compression, the quantum-confinement effect has a pronounced impact on the reduction in the current density in compressive-strained wells. This makes either type of strain attractive for reducing the threshold current density in InP-based SL-SQW lasers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357468
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  • 7
    Electronic Resource
    Electronic Resource
    Theoretical analysis of differential gain of 1.55 μm InGaAsP/InP compressive-strained multiple-quantum-well lasers (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 1299-1303 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Basic design principles are formulated for increasing the differential gain of 1.55 μm InGaAsP/InP compressive-strained multiple-quantum-well (MQW) lasers. An InGaAsP quaternary active layer can provide more freedom of design compared to an InGaAs ternary active layer since the amount of strain and the quantum-well thickness can be independently determined in an InGaAsP material system for a given emission wavelength. Compressive strain ranging from 1% to 1.5% is large enough to reduce the density of states below one-third of that of unstrained wells. No further reduction is expected even if more compressive strain is applied. When the well thickness is, in turn, determined, it is essential to incorporate a trade-off between the conduction and valence subband energy spacings and the squared optical matrix elements. The extra enhancement of differential gain in MQW structures with a modulation p doping is also studied. By designing MQW structures according to these principles, differential gain can be increased to over 2×10−15 cm2, which corresponds to a relaxation oscillation frequency of more than 30 GHz at an output power of 20 mW.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.356407
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  • 8
    Electronic Resource
    Electronic Resource
    Dominant mechanism for limiting the maximum operating temperature of InP-based multiple-quantum-well lasers (1996)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 2192-2197 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We study the basic mechanism for limiting the maximum operating temperature (Tm) of InP-based multiple-quantum-well (MQW) lasers emitting at a wavelength of 1.3 μm. It is shown that laser operation is characterized in terms of the temperature dependence of threshold gain (gth) by introducing a critical temperature (Tc): gth exhibits a linear relationship with temperature below Tc, while it superlinearly increases with increasing temperature above Tc. This rapid increase in gth leads to a marked increase in threshold current and a significant reduction in differential quantum efficiency above Tc. We indicate that Tc exhibits a direct correlation with Tm: the higher Tc, the higher Tm. In the temperature range above Tc, laser operation moves into a loss-multiplication regime, where a considerable portion of the injected carriers brings about a significant increase in internal loss rather than gain due to their pileup in the separate confinement heterostructure layers. We demonstrate that an anomalous increase in internal loss, which occurs at the final stage in this loss-multiplication regime, determines Tm of 1.3 μm InP-based MQW lasers. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.361183
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  • 9
    Electronic Resource
    Electronic Resource
    The effects of strain on intrasubband scattering rates in InP-based strained-layer quantum-well lasers (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 7399-7404 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We analyze the strain effects (both compressive and tensile) on the intrasubband scattering rates for electrons and holes in InP-based strained-layer quantum-well (SL-QW) lasers. Carrier-carrier and carrier-LO-phonon interactions are taken into account on an equal basis within the fully dynamic random phase approximation for multi-subband structures at finite temperatures. The principal influences of the strain-induced changes in the valence band structures on the scattering rates are discussed in terms of the changes in the valence-band density of states and the phonon coupling with holes. We show that the hole-hole interaction plays a dominant role in determining the hole scattering rates regardless of the carrier energy. On the other hand, for electron scattering rates, the dominant scattering mechanism switches from electron-hole interaction to electron-electron interaction as the initial energy of electron increases. We also demonstrate that it is essential to take into account the mutual interactions among the individual scattering processes, such as carrier-carrier scattering and carrier-LO-phonon scattering, when evaluating the intrasubband scattering rates in SL-QW lasers. © 1994 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357965
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  • 10
    Electronic Resource
    Electronic Resource
    Dependence of valence-subband dispersion relations on heterointerface boundary conditions in InxGa1−xAsyP1−y/InP narrow quantum wells (1994)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 2347-2356 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: In the framework of envelope function approximation, the dependence on heterointerface boundary conditions of valence-band dispersion relations in InP-based quantum-well structures is investigated. Under conventional boundary conditions, the root-finding calculation for the eigenvalue problem of quantum well structures is carried out while taking into account a large difference in the effective-mass parameters (the Luttinger parameters) among the constituting bulk materials. In spite of a decreasing interband mixing between heavy- and light-hole states due to strain and the quantum size effect, hole subband structure of a compressive-strained quantum well with a narrow well width is found to form an anomalous dispersion curve. It is clarified that the requirement for envelope continuity at interfaces is responsible for anomaly in the dispersion curves through off-diagonal terms with an additional δ-function-like interface potential in the valence-band effective-mass Hamiltonian. We present the results of dispersion relations and envelope functions related to a newly derived connection rule based on the tight-binding bond-orbital description, under which the envelopes are free from continuity restrictions at the interfaces regardless of any difference in the effective-mass parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.357580
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