[TuP3D] D. Photonic devices and related technologies

[TuP3D-07] Waveguide Edge-Emission of a Circular Defect in 2D Photonic Crystal (CirD) Laser with InAs Quantum Dot Embedded within The Cavity Area

〇Yusuke Yahata¹, Masato Morifuji¹, Hirotake Kajii¹, Tetsuya Yagi¹, Akihiko Maruta¹, Nobuhiko Kikuchi¹, Masakazu Arai², Masahiko Kondow¹ (1. The Univ. of Osaka (Japan), 2. The Univ. of Miyazaki (Japan))

This study focuses on enhancing circular defect in 2D photonic crystal (CirD) lasers for on-chip optical communications. To improve efficiency, the authors proposed a localized quantum dot (QD) structure where InAs QDs are embedded exclusively within the cavity area to reduce absorption losses.Fabrication involved SiO₂ masking and ICP-RIE, followed by GaAs regrowth to confine the QD region. A key achievement was improving the positioning precision between the QD region and the CirD cavity. Experimental results confirmed that alignment errors were suppressed to 10 nm in the x-direction and 30 nm in the y-direction.Optical measurements under continuous wave pumping at room temperature successfully demonstrated facet emission from the waveguide. Notably, the threshold power was reduced to 25 µW, reaching the ideal theoretical value. This confirms that precise spatial control of the gain medium effectively optimizes CirD laser characteristics.