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Mathematics

Gain-Switched Short Pulse Generation from 1.55 µm InAs/InP/(113)B Quantum Dot Laser Modeled Using Multi-Population Rate Equations

Hilal Sultan Duranoglu Tunc, Nuran Dogru, Erkan Cengiz

Published Nov 17, 2022• 4 citations
Publisher

Abstract

For the first time the gain switching properties of an InAs-InP (113)B quantum dot laser are examined theoretically in detail to generate shorter pulses with the application of a Gaussian pulse beam to the laser excited state. The multi population rate equations considering nonlinear gain are solved by the Runge –Kutta method. The numerical results demonstrated that as the homogeneous and the inhomogeneous broadening increase, the differential gain, the gain compression factor and the threshold current of excited state decrease, while threshold current of ground state increases. It was also observed that the contribution of the excited state to gain-switched output pulses depends on not only the value of the inhomogeneous broadening but also the magnitude of the applied current. Finally it was shown that without an optical beam, output pulse has long pulse width due to ground state emission, whereas with an optical beam, narrow pulses having high peak power owing to the excited state emission are generated even though at low currents.

DOI
10.3390/math10224316

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We report on multi-wavelength pump-probe characterization of the fundamental gain dynamics in recently developed InAs/InP quantum-dot semiconductor optical amplifiers. Recovery of the gain at various wavelengths following a powerful optical pump pulse, was recorded at different bias levels and different excitation powers. Wavelength dependencies of gain saturation depth, of the level to which the gain recovers and of the recovery rates were obtained. Unlike in quantum-dash amplifiers, these quantum-dots exhibit no instantaneous gain response, confirming their zero-dimensional nature.
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