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Memoirs of the Graduate School of Engineering Kobe University, No. 1, pp. 1-8, 2009
doi:10.5047/gseku.e.2009.002

Controlling Polarization in Quantum-dot Semiconductor Optical Amplifiers

Nami YASUOKA1, Hiroji EBE2, Kenichi KAWAGUCHI3, Mitsuru EKAWA4, Takashi KITA5, Osamu WADA6, Mitsuru SUGAWARA7, Toshio SAITO8, and Yasuhiro ARAKAWA9 1 Fujitsu Limited and Optoelectronic Industry and Technology Development Association
2 Institute for Nano Quantum Information Electronics (INQIE), The University of Tokyo
3 Fujitsu Limited and Optoelectronic Industry and Technology Development Association
4 Fujitsu Laboratories Limited
5 Department of Electrical and Electronics Engineering, Facility of Engineering, Kobe University
6 Department of Electrical and Electronics Engineering, Facility of Engineering, Kobe University
7 Fujitsu Laboratories Limited and QD Laser Incorporated
8 Institute for Nano Quantum Information Electronics (INQIE), The University of Tokyo
9 Institute for Nano Quantum Information Electronics (INQIE), Institute of Industrial Science (IIS), Research Center for Advanced Science and Technology (RCAST), The University of Tokyo

(Received November 13, 2009; Accepted January 12, 2010; Online published January 18, 2010)

Keywords: semiconductor optical amplifier, quantum dots, polarization

The possibility of applying a polarization-insensitive quantum-dot (QD) semiconductor optical amplifier (QD-SOA) to future optical communication systems is demonstrated. It was found that the optical-polarization property of a QD depends on both its aspect ratio and strain. To control these two parameters, a columnar QD (CQD), which has a high aspect ratio and is surrounded by side-barriers, was optimized. These optimized CQDs demonstrated polarization-insensitive characteristics in the 1.5-μm wavelength band. Moreover, they have a gain of 10.0 dB with low (i.e., ± 0.9 dB) polarization dependence.


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