Iman Taghavi

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In this paper, we introduce an approximate way to estimate the optical confinement factor (OCF) in Double Heterostructure Long Wavelength Transistor Lasers (DH-LWTL). Calculating the steady state electron density and differential optical gain, we investigate the OCF effects on the device DC performances as a function of the base width. Our results exhibit(More)
In this paper we will report analysis of a quantum-well (160 Aring QW) Transistor Laser with 150 mum cavity length using a charge control model in order for modifying QW location through base region. The analysis shows significant enhancement, at constant bias currents, in optical bandwidth due to moving the QW in the direction of collector-base junction.(More)
Graded index separate confinement heterostructure (GRIN-SCH) has been suggested for n-InGaP/p<sup>+</sup>-GaAs+i-InGaAs/i-GaAs single quantum well (SQW) transistor laser (TL) with linearly graded In<sub>&#x03BE;</sub>Ga<sub>1-&#x03BE;</sub>As in base region (&#x03BE; : 0 &#x2192; 0.029 emitter to QW and &#x03BE; : 0.038 &#x2192; 0.05 from QW to collector).(More)
We report a numerical method based on experimental data and modified charge control model to simulate quantum-well dislocation effect inside the base region of a Transistor Laser with 150&amp;#956;m cavity length. Utilizing a reverse calculation method, base recombination lifetime is simulated in order to investigate optical bandwidth dependence on quantum(More)
Base width variation effects on resonance frequency and resonance peak of Double-Hetero structure Long Wavelength Transistor Laser (DH-LWTL) is investigated. Resonance behavior has significant effects on optoelectronic performance of LWTL that calculated through its frequency response. In our structure, resonance peak maximized to 16.23 dB in 135 nm base(More)
In this paper an analysis of a typical Heterojunction Bipolar Transistor Laser (HBTL) with a 160&#x00C5; quantum-well in the base is developed to describe the Base width effect on optical frequency response and current gain using a charge control model. We have found that base width has an optimized value of about 1000&#x00C5; for the highest &#x2212;3db(More)
We report a numerical method based on both experimental data and physical model to simulate quantum-well dislocation effect inside the base region of a transistor laser of 150&#x03BC;m cavity length. Utilizing a special calculation method, base recombination lifetime is simulated for different quantum-well locations. In order to investigate optical(More)
Eighty-six children under one year of age with univentricular hearts associated with increased pulmonary flow underwent pulmonary artery banding as the first stage of palliative therapy. Fifteen patients also had treatment of coarctation of the aorta at the same time and an atrial septal defect was treated in 13 patients. Twenty-seven patients underwent a(More)
In this paper, we address the problem of direction-of-arrival (DOA) estimation using a novel spatial sampling scheme based on difference set (DS) codes, called DS-spatial sampling. It is shown that the proposed DS-spatial sampling scheme can be modeled by a deterministic dictionary with minimum coherence. We also develop a low complexity compressed sensing(More)