24 research outputs found

    Modeling the effects of p-modulation doping in InAs quantum dot devices

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    a modeling routine has been developed to quantify the effects of p-modulation doping in the waveguide core region of InAs quantum dot (QD) devices. Utilizing one dimensional approximations, simulated outputs of reverse and forward devices are simulated providing insight into absorption and gain properties

    QCSE and carrier blocking in P-modulation doped InAs/InGaAs quantum dots

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    The quantum confined Stark effect in InAs/InGaAs QDs using an undoped and p-modulation doped active region was investigated. Doping potentially offers more than a 3x increase in figure of merit modulator performance up to 100°C

    1.3-μm InAs Quantum Dot Lasers with P-type modulation and direct N-type co-doping

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    O-band quantum dot lasers with co-doping reduce threshold current density relative to the undoped case, for 1mm long uncoated lasers from 245Acm-2 to 132Acm-2 at 27°C and 731Acm-2 to 312Acm-2 at 97°C. Improvements are also significant compared to lasers employing any one doping strategy

    Co-doped 1.3μm InAs Quantum Dot Lasers with high gain and low threshold current

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    The mechanism by which co-doping reduces threshold current in O-band Quantum dot lasers is examined, with n-type direct doping of the dots reducing threshold current and p-type modulation doping improving the temperature dependence of threshold current density, relative to undoped samples

    Si-based 1.3 μm InAs/GaAs QD Lasers

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    The effects of implementing Ge and Si buffer layers on the performance of Si-based InAs/GaAs quantum dot lasers have been investigated in this paper. The laser performance has been improved significantly by utilising group-IV buffer layers

    Degradation of III–V Quantum Dot Lasers Grown Directly on Silicon Substrates

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    Initial age-related degradation mechanisms for InAs quantum dot lasers grown on silicon substrates emitting at 1.3 μm are investigated. The rate of degradation is observed to increase for devices operated at higher carrier densities and is therefore dependent on gain requirement or cavity length. While carrier localization in quantum dots minimizes degradation, an increase in the number of defects in the early stages of aging can increase the internal optical-loss that can initiate rapid degradation of laser performance due to the rise in threshold carrier density. Population of the two-dimensional states is considered the major factor for determining the rate of degradation, which can be significant for lasers requiring high threshold carrier densities. This is demonstrated by operating lasers of different cavity lengths with a constant current and measuring the change in threshold current at regular intervals. A segmented-contact device, which can be used to measure the modal absorption and also operate as a laser, is used to determine how the internal optical-loss changes in the early stages of degradation. Structures grown on silicon show an increase in internal optical loss, whereas the same structure grown on GaAs shows no signs of increase in internal optical loss when operated under the same conditions

    Increasing Maximum Gain in InAs Quantum Dot Lasers on GaAs and Si

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    InAs quantum-dot (QD) lasers emitting at 1300nm with nominally undoped and modulated p-type doping are studied. Modal-gain measurements indicate a higher gain can be achieved from the ground-state for a given Fermi-level separation with p-doping and a reduced temperature-dependence of threshold current for short-cavity lasers

    Evaluating InAs QD lasers for space borne applications

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    Decrease of photoluminescence with increasing dose is due to bombardment induced wetting layer non-radiative recombination. To exploit the relative radiation immunity of QD lasers one should maximise the QD density and capture probability per dot. © 2012 IEEE

    Evaluating InAs QD lasers for space borne applications

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    Decrease of photoluminescence with increasing dose is due to bombardment induced wetting layer non-radiative recombination. To exploit the relative radiation immunity of QD lasers one should maximise the QD density and capture probability per dot. © 2012 IEEE
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