Broadband Light Source Based on Four-Color Self-Assembled InAs Quantum Dot Ensembles Monolithically Grown in Selective Areas

Nobuhiko OZAKI  Koichi TAKEUCHI  Shunsuke OHKOUCHI  Naoki IKEDA  Yoshimasa SUGIMOTO  Kiyoshi ASAKAWA  Richard A. HOGG  

IEICE TRANSACTIONS on Electronics   Vol.E95-C   No.2   pp.247-250
Publication Date: 2012/02/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E95.C.247
Print ISSN: 0916-8516
Type of Manuscript: BRIEF PAPER
quantum dot,  selective-area growth,  metal mask,  optical coherence tomography,  superluminescent diode,  

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We developed advanced techniques for the growth of self-assembled quantum dots (QDs) for fabricating a broadband light source that can be applied to optical coherence tomography (OCT). Four QD ensembles and strain reducing layers (SRLs) were grown in selective areas on a wafer by the use of a 90° rotational metal mask. The SRL thickness was varied to achieve appropriate shifts in the peak wavelength of the QD emission spectrum of up to 120 nm. The four-color QD ensembles were expected to have a broad bandwidth of more than 160 nm due to the combination of excited state emissions when introduced in a current-induced broadband light source such as a superluminescent diode (SLD). Furthermore, a desired shape of the SLD spectrum can be obtained by controlling the injection current applied to each QD ensemble. The broadband and spectrum shape controlled light source is promising for high-resolution and low-noise OCT systems.