Carrier Dynamics of Quantum-Dot, Quantum-Dash, and Quantum-Well Semiconductor Optical Amplifiers Operating at 1.55 μm

• Published in: IEEE journal of quantum electronics Vol. 43; no. 11-12; pp. 982 - 991
• Main Authors: ZILKIE, Aaron J, MEIER, Joachim, SMITH, Peter W. E, AITCHISON, J. Stewart, MOJAHEDI, Mo, POOLE, Philip J, BARRIOS, Pedro, POITRAS, Daniel, ROTTER, Thomas J, CHI YANG, STINTZ, Andreas, MALLOY, Kevin J
• Format: Journal Article
• Language: English
• Published: New York, NY Institute of Electrical and Electronics Engineers 01.11.2007
• Subjects: Amplification; Amplifiers; Devices; Dynamics; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Gain; Laser optical systems: design and operation; Optical computers, logic elements, interconnects, switches; neural networks; Optical elements, devices, and systems; Optics; Physics; Quantum dots; Quantum wells; Resonators, cavities, amplifiers, arrays, and rings; Semiconductor optical amplifiers; Quantum confinement; Quantum wires; Gallium arsenides; Energy levels; Semiconductor devices; Charge carrier lifetime; Indium phosphide; Quantum amplifier; Transients; Semiconductor optical amplifiers; Line broadening; semiconductor optical amplifiers (SOAs); Quantum dot devices; quantum dots (QDs); Carrier lifetime; Semiconductor switches; Gain recovery; Carrier mobility; Optical modulation; Quaternary compounds; ns range; ps range; quantum wells (QWs); Optical information processing; Charge carriers; Phase shift; Quantum dots; Quantum wells; Binary compounds; Gallium phosphide; Experimental study; Indium arsenides; quantum-effect semiconductor devices; Signal processing; Optical amplifier; optical signal processing; Carrier density; III-V semiconductors
• ISSN: 0018-9197; 1558-1713
• DOI: 10.1109/JQE.2007.904474

We assess the influence of the degree of quantum confinement on the carrier recovery times in semiconductor optical amplifiers (SOAs) through an experimental comparative study of three amplifiers, one InAs-InGaAsP-InP quantum dot (0-D), one InAs-InAlGaAs-InP quantum dash (1-D), and one InGaAsP-In-GaAsP-InP quantum well (2-D), all of which operate near 1.55-mum wavelengths. The short-lived (around 1 ps) and long-lived (up to 2 ns) amplitude and phase dynamics of the three devices are characterized via heterodyne pump-probe measurements. The quantum-dot device is found to have the shortest long-lived gain recovery (~80 ps) as well as gain and phase changes indicative of a smaller linewidth enhancement factor, making it the most promising for high-bit-rate applications. The quantum-dot amplifier is also found to have reduced ultrafast transients, due to a lower carrier density in the dots. The quantum-dot gain saturation characteristics and temporal dynamics also provide insight into the nature of the dot energy-level occupancy and the interactions of the dot states with the wetting layer.