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Growth of Columnar Quantum Dots by Metalorganic Vapor-Phase Epitaxy for Semiconductor Optical Amplifiers

Growth of polarization-controlled quantum dots (QDs) by metalorganic vapor-phase epitaxy for semiconductor optical amplifiers (SOAs) is reported. Columnar QDs with small lateral sizes and high aspect ratios were formed using low growth temperatures and highly tensile-strained barriers. Dominant polarization sensitivities of columnar QDs were changed from the transverse-electric (TE) mode to the transverse-magnetic (TM) mode by controlling the heights of columnar QDs and tensile-strained barriers. TM-gain-dominant-QD SOAs were fabricated. A TM-mode gain of 17.3 dB was obtained at a wavelength of 1.55 µm. Polarization dependent gain was tuned by barrier thickness and reduced to 2.5 dB.