Abstract
Highly coherent quantum emitters operating in the telecommunication C-band (1530 - 1565nm), where ultra-low-loss fibers and photonic circuits are available, are crucial to the development of scalable quantum technologies. In this work, we report on a modified Stranski-Krastanov growth scheme using chemical beam epitaxy to enable the generation of high-quality InAs/InP quantum dots, characterized by near-transform-limited linewidths (Γ_TL). We demonstrate the growth of highly-symmetric quantum dots with aspect ratios >0.8 and densities ranging from 2 to 22μm⁻². Optical characterization of these sources reveal fine-structure splittings down to 25±4μeV and a single-photon purity of g⁽²⁾(0) = 0.012±0.007, confirming the quality of these dots. Further, using an etalon to measure the linewidth, in combination with rigorous modelling, we find an upper-bound to the mean, low-power linewidths of only 12.1± 6.7ΓTL and, in the best case, 2.8± 1.8ΓTL. These results represent a significant step in the development of telecom-wavelength quantum light sources which are essential for complex quantum networks and devices.