Investigation of Cross Gain Modulation in Quantum-Dot Amplifier Using
Four-Level Rate Equations Model
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Full Text |
Pdf |
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Author |
R. S. Fyath, Abdul Kareem H. Dagher, Hussein H. Warid
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ISSN |
2079-8407 |
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On Pages
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896-906
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Volume No. |
3
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Issue No. |
6
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Issue Date |
June 01, 2012 |
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Publishing Date |
June 01, 2012 |
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Keywords |
QD-amplifier, Wavelength conversion, Cross gain modulation
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Abstract
An analytical model for the small-signal cross gain modulation (XGM) in undoped quantum dot (QD) - semiconductor optical
amplifiers (SOAs) is derived using four-level rate equations model (4LREM),. The model takes into account the effect of
wetting layer (WL), the continuum states (CS), excited states (ES), and the nonlinear optical gain of the dots. The calculated
small-signal conversion efficiency is compared with those predicated from the three-level rate equations model (3LREM). The
results show that the CS acts as a carrier reservoir for the lower energy states. Also, the reduced intersubband from the upper
excited to ground state carrier relaxation time will increase the XGM conversion efficiency. The present analysis also provides
insight on the escape/relaxation lifetimes of the QD amplifier which is very important for characterizing and understanding the
performance characteristics of other similar-structure devices.
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