Abstract
This paper reviews a near-infrared (NIR) superluminescent diode (SLD) based on self-assembled InAs
quantum dots (QDs). Self-assembled InAs QDs exhibiting a broadband NIR spectrum due to their size
and In composite distributions are suitable for optical coherence tomography (OCT) applications. We
developed a QD-based SLD (QD-SLD) and demonstrated high-axial-resolution OCT imaging using the
QD-SLD. InAs QD layers with controlled emission wavelengths were grown on GaAs, and an edgeemitting
SLD with a tilted waveguide and segmented electrodes was fabricated. An electroluminescence
spectrum spanning approximately 1 - 1.3 μm with a bandwidth of 144 nm was obtained, and the inverse
Fourier transform of the spectrum predicted an axial-resolution of 3.6 μm in air. OCT images of test
samples obtained with the QD-SLD actually indicated an axial resolution of ~4 μm, which is less than
that of a conventional OCT (10 - 15 μm). This practical imaging demonstrates the potential of the QDSLD
as a high-axial-resolution OCT light source.
