Superluminescent diode with a broadband gain based on self-assembled InAs quantum dots and segmented contacts for an optical coherence tomography light source

Ozaki, N. et al. (2016) Superluminescent diode with a broadband gain based on self-assembled InAs quantum dots and segmented contacts for an optical coherence tomography light source. Journal of Applied Physics, 119(8), 083107. (doi: 10.1063/1.4942640)

Abstract

We report a broadband-gain superluminescent diode (SLD) based on self-assembled InAsquantum dots(QDs) for application in a high-resolution optical coherence tomography(OCT) light source. Four InAsQD layers, with sequentially shifted emission wavelengths achieved by varying the thickness of the In0.2Ga0.8As strain-reducing capping layers, were embedded in a conventional p-n heterojunction comprising GaAs and AlGaAs layers. A ridge-type waveguide with segmented contacts was formed on the grown wafer, and an as-cleaved 4-mm-long chip (QD-SLD) was prepared. The segmented contacts were effective in applying a high injection current density to the QDs and obtaining emission from excited states of the QDs, resulting in an extension of the bandwidth of the electroluminescence spectrum. In addition, gain spectra deduced with the segmented contacts indicated a broadband smooth positive gain region spanning 160 nm. Furthermore, OCTimaging with the fabricated QD-SLD was performed, and OCTimages with an axial resolution of ∼4 μm in air were obtained. These results demonstrate the effectiveness of the QD-SLD with segmented contacts as a high-resolution OCT light source.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Childs, Dr David and Hogg, Professor Richard
• Authors: Ozaki, N., Childs, D. T. D., Sarma, J., Roberts, T. S., Yasuda, T., Shibata, H., Ohsato, H., Watanabe, E., Ikeda, N., Sugimoto, Y., and Hogg, R. A.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Journal of Applied Physics
• Publisher: American Institute of Physics
• ISSN: 0021-8979
• ISSN (Online): 1089-7550