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Thermal Effects and Small Signal Modulation of 1.3- μ m InAs/GaAs Self-Assembled Quantum-Dot Lasers

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ABSTRACT

We investigate the influence of thermal effects on the high-speed performance of 1.3-μm InAs/GaAs quantum-dot lasers in a wide temperature range (5–50°C). Ridge waveguide devices with 1.1 mm cavity length exhibit small signal modulation bandwidths of 7.51 GHz at 5°C and 3.98 GHz at 50°C. Temperature-dependent K-factor, differential gain, and gain compression factor are studied. While the intrinsic damping-limited modulation bandwidth is as high as 23 GHz, the actual modulation bandwidth is limited by carrier thermalization under continuous wave operation. Saturation of the resonance frequency was found to be the result of thermal reduction in the differential gain, which may originate from carrier thermalization.

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Plot of temperature-dependence of K-factor.
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Figure 7: Plot of temperature-dependence of K-factor.

Mentions: Measurements of direct small signal modulation of the QD laser were carried out from 5 to 50°C. Figure 4 shows the maximum measured (triangles) bandwidth (f3dB, measured) as function of temperature. The maximum measured bandwidth decreases almost linearly with temperature as temperature increases from 5 to 50°C. The highest f3dB, measured of 7.51 GHz occurred at 5°C. The D-factor is 0.36 GHz/mA1/2 at 5°C and 0.15 GHz/mA1/2 at 50°C as shown in Figure 5 (solid circles). The differential gain from 5 to 50°C decreases following increase in temperature as shown in Figure 6. Figure 7 shows the calculated K-factor of the QD laser as function of temperature. There is a significant increase in the K-factor as temperature increases. The calculated K-factor increases approximately by a factor of three over the temperature range of 5–50°C.


Thermal Effects and Small Signal Modulation of 1.3- μ m InAs/GaAs Self-Assembled Quantum-Dot Lasers
Plot of temperature-dependence of K-factor.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211460&req=5

Figure 7: Plot of temperature-dependence of K-factor.
Mentions: Measurements of direct small signal modulation of the QD laser were carried out from 5 to 50°C. Figure 4 shows the maximum measured (triangles) bandwidth (f3dB, measured) as function of temperature. The maximum measured bandwidth decreases almost linearly with temperature as temperature increases from 5 to 50°C. The highest f3dB, measured of 7.51 GHz occurred at 5°C. The D-factor is 0.36 GHz/mA1/2 at 5°C and 0.15 GHz/mA1/2 at 50°C as shown in Figure 5 (solid circles). The differential gain from 5 to 50°C decreases following increase in temperature as shown in Figure 6. Figure 7 shows the calculated K-factor of the QD laser as function of temperature. There is a significant increase in the K-factor as temperature increases. The calculated K-factor increases approximately by a factor of three over the temperature range of 5–50°C.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

We investigate the influence of thermal effects on the high-speed performance of 1.3-μm InAs/GaAs quantum-dot lasers in a wide temperature range (5–50°C). Ridge waveguide devices with 1.1 mm cavity length exhibit small signal modulation bandwidths of 7.51 GHz at 5°C and 3.98 GHz at 50°C. Temperature-dependent K-factor, differential gain, and gain compression factor are studied. While the intrinsic damping-limited modulation bandwidth is as high as 23 GHz, the actual modulation bandwidth is limited by carrier thermalization under continuous wave operation. Saturation of the resonance frequency was found to be the result of thermal reduction in the differential gain, which may originate from carrier thermalization.

No MeSH data available.