Analysis of linewidth enhancement factor for quantum well structures based on InGaAsN/GaAs material system

Miloszewski, Jacek M.; Wartak, Marek S.; Weetman, P.; Hess, Ortwin

doi:10.1063/1.3223288

Cited by 13 publications

(15 citation statements)

References 19 publications

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“…In our computational results, the total number of dips is 1.43 × 10 6 for α = 3 and 5.5 × 10 5 for α = 2, which also suggests that the employed SOA in [5] has an LWEF that varies between 2 and 3. It should be reiterated that the time dependency of the LWEF is not considered in this study, as was the case with prior studies [2,[5][6][7][8][9][10][15][16][17][18][19]. Hence, our estimation for the LWEF of the employed SOA involves a range of values (2 < α < 3) over a single roundtrip rather than a constant value.…”

Section: Comparison With Experimental Resultsmentioning

confidence: 95%

“…8 shows another undesired effect of a high LWEF on the intracavity signal, which is significant decrease in power. Fortunately, most quantum well-based SOAs have LWEFs that are in the range of 1-5 [16]. Hence, the issue of LWEF related power-loss is relatively less significant in an FDML laser cavity as compared to dip formation.…”

Section: Convergence Of Error Versus Lwefmentioning

confidence: 99%

“…The LWEF stems from the refractive index fluctuations within the SOA active region owing to the variation in carrier density [10][11][12][13]. The value of the LWEF usually ranges from 1 to 10 for bulk SOAs, though it is shown to be much smaller for multiple quantum well (MQW)-based SOAs [14][15][16][17]. For SOAs with quantum-dot based active regions, the LWEF is shown to be extremely small (almost zero) [15] due to three-dimensional electron confinement.…”

Section: Introductionmentioning

confidence: 99%

“…The FDML laser dynamics are mainly determined by the dynamics of the SOA; therefore, the power-dips should originate due to the nonlinear SOA active region dynamics [6]. This is easy to predict since a high SOA LWEF signifies large fluctuations in the refractive index of the active region, which naturally cause sharp changes in the signal pattern [12][13][14][15][16][17][18][19]. Hence, we believe that using an SOA with a high LWEF is very likely to exacerbate the power fluctuations in an FDML laser output signal by amplifying the occurrence of power-dips.…”

Section: Introductionmentioning

confidence: 99%

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Influence of the linewidth enhancement factor on the signal pattern of Fourier domain mode-locked lasers

2022

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Fourier domain mode-locked (FDML) lasers are frequency-swept lasers that operate in the near-infrared region and allow for the attainment of a large sweep-bandwidth, high sweep-rate, and a narrow instantaneous linewidth, all of which are usually quite desirable characteristics for a frequency-swept laser. They are used in various sensing and imaging applications but are most commonly noted for their practical use in optical coherence tomography (OCT). An FDML laser consists of three fundamental components, which are the semiconductor optical amplifier (SOA), optical fiber, and the wavelength-swept optical bandpass filter. Due to the complicated nonlinear dynamics of FDML lasers that stems from the coaction of these three components, often the output signal of an FDML laser is corrupted by frequent power-dips of varying depth and duration. The frequent recurrence of these dips in the FDML laser signal pattern lowers the quality of imaging and detection. This study examines the role of the linewidth enhancement factor (LWEF) of an SOA in reducing both the strength and the number of power-dips throughout the FDML laser operation. The results are obtained using numerical computations that are in agreement with experimental data. The study aims to show that using SOAs with low LWEFs, the number of power-dips can be reduced for a better detection and imaging quality.

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Section: Comparison With Experimental Resultsmentioning

confidence: 95%

Section: Convergence Of Error Versus Lwefmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of the linewidth enhancement factor on the signal pattern of Fourier domain mode-locked lasers

2022

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“…The insertion was introduced by N plasma irradiation during a growth interruption. Finally, a 150 nm thick GaAs cap layer was grown at the same temperature of 420 C. Thin cross-sectional TEM foils were prepared along the [110] and the orthogonal [1][2][3][4][5][6][7][8][9][10] projections. The specimens were thinned by mechanical polishing followed by Ar-ion milling.…”

mentioning

confidence: 99%

Strain-induced composition limitation in nitrogen δ-doped (In,Ga)As/GaAs quantum wells

Gargallo-Caballero

Luna

Ishikawa

et al. 2012

Applied Physics Letters

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Articles you may be interested inMolecular beam epitaxial growth and characterization of nitrogen δ-doped AlGaAs/GaAs quantum wells J. Vac. Sci. Technol. B 30, 02B117 (2012); 10.1116/1.3678204 Strain-induced nitrogen incorporation in atomic layer epitaxy growth of InAsN/GaAs quantum wells using metal organic chemical vapor deposition Appl. Phys. Lett. 95, 051102 (2009); 10.1063/1.3193663 Influence of strain-induced indium clustering on characteristics of InGaN/GaN multiple quantum wells with high indium composition Anisotropic surface segregation of indium atoms in molecular beam epitaxy of InGaAs/GaAs quantum wells

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Desıgn of quantum-dot semiconductor optical amplifiers wıth near-zero linewidth enhancement factor

Aşırım,

Jirauschek

2024

Opt Quant Electron

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The linewidth enhancement factor (LWEF) of a semiconductor optical amplifier (SOA) quantifies refractive index fluctuations in the gain medium, which induce phase distortion in the amplified optical signal. Optoelectronic systems employing SOAs with high LWEFs often exhibit poor device stability and beam coherence. Thus, designing SOAs with low LWEF is imperative. Recently, Quantum-Dot (QD) SOAs have emerged as a solution for LWEF suppression due to quantum-confinement effects enabling tunability of the QD carrier density and emission frequency. In this study, we aim to design a composite active region comprised of a host medium and the embodied QDs, to explore the corresponding LWEF variation and propose the ultimate design strategy to achieve near-zero LWEF in QD SOAs for enhancing device stability and beam coherence. Our approach entails modeling the refractive index of the composite active region using effective medium approximation via Maxwell–Garnett mixing formulation. We then extensively tune key SOA parameters, including QD carrier density, QD emission frequency, and the collision-time constant of the carriers to uncover the optimal configuration for minimizing the LWEF. Based on empirical values, we have developed and validated a simple yet effective algorithm that precisely simulates LWEF behavior in response to changes in key QD SOA parameters. This approach offers a straightforward model for estimating LWEF variation, and its corresponding minimization in QD SOAs without requiring complex experimental measurement techniques.

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Analysis of linewidth enhancement factor for quantum well structures based on InGaAsN/GaAs material system

Cited by 13 publications

References 19 publications

Influence of the linewidth enhancement factor on the signal pattern of Fourier domain mode-locked lasers

Influence of the linewidth enhancement factor on the signal pattern of Fourier domain mode-locked lasers

Strain-induced composition limitation in nitrogen δ-doped (In,Ga)As/GaAs quantum wells

Desıgn of quantum-dot semiconductor optical amplifiers wıth near-zero linewidth enhancement factor

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