Fabrication of GaAs Core Layer with InAs Quantum Dots Embedded within the Cavity Area for Circular Defect in 2D Photonic Crystal Lasers

To address the low output power issue of circular defect in 2D photonic crystal (PhC) lasers, we propose a novel fabrication process that spatially confines the active quantum dot (QD) region within the laser cavity. Our goal is to confine the QDs within the resonator while removing them from the waveguide region. Selective etching by inductively coupled plasma etching and selective regrowth by metal–organic chemical vapor deposition are used to remove QDs from the waveguide region while confining them within the resonator. Scanning electron microscopy imaging and optical measurements demonstrate that a flat regrown surface is obtained and confirm the presence of a whispering gallery mode in the fabricated structures. Furthermore, lasing is observed at a threshold of 28 μW. These results validate the effectiveness of spatially confining QDs as a technique for improving device performance and provide insight into efficient optical control by PhC structures. Our findings also indicate that selective core regrowth is a viable strategy to increase the efficiency of laser output by minimizing QD‐induced absorption losses.