In the present study, we report on the deterministic integration of quantum dots, emitting in the telecom O-band, into wet-chemically fabricated Gaussian-shaped microlenses which exhibit a surface quality comparable to epi-ready wafers. The slow wet-chemical etching rate enables us to gain control of the lens aspect-ratio and the vertical position with respect to the quantum dot, allowing us to engineer the far field shape to better match the acceptance profile of single-mode fibers. Maximum light enhancement values of around 10 to 16 could be achieved for collection numerical apertures from 0.6 to 0.2, respectively. The current results constitute an important step forward in transferring state-of-the-art performances achieved in the near-infrared regime to the key wavelengths for long distance fiber communication.
Publication: Deterministic integration and optical characterization of telecom O-band quantum dots embedded into wet-chemically etched Gaussian-shaped microlenses
M. Sartison, L. Engel, S. Kolatschek, F. Olbrich, C. Nawrath, S. Hepp, M. Jetter, P. Michler and S. L. Portalupi 
Appl. Phys. Lett. 113, 032103 (2018)
Contact person: M. Sartison