We fabricated and characterized a grating-coupled external cavity laser with gain chips including self-assembled InAs quantum dots (QDs) for swept-source optical coherence tomography applications. By controlling the emission wavelength of the self-assembled InAs QDs, tunable lasing at a wavelength band of 1–1.1 μm was obtained, which represents an optimal balance between absorption and scattering in biological tissues. Straight and J-shaped edgeemitting ridge waveguides (RWGs) were fabricated on a GaAs-based waveguide layer containing four InAs QDs layers. A diffraction grating with the quasi-Littrow configuration was employed as an external cavity for the fiber-coupled diodes. Electroluminescence spectra from the QD-based diodes revealed that broadband amplified spontaneous emissions appeared in a J-shaped RWG, whereas Fabry–Perot lasing occurred in the straight RWG. The external cavity was then introduced for the diode with a J-shaped RWG, and a tuning range of 65 nm centered at approximately 1100 nm was obtained from the QD gain chip with the J-shaped RWG.

Date Published: 1 March 2019
PDF: 6 pages
Proc. SPIE 10939, Novel In-Plane Semiconductor Lasers XVIII, 1093911 (1 March 2019); doi: 10.1117/12.2509984

Published in SPIE Proceedings Vol. 10939:
Novel In-Plane Semiconductor Lasers XVIII
Alexey A. Belyanin; Peter M. Smowton, Editor(s)