InP-based single-photon sources operating at telecom C-band with increased extraction efficiency

In this work, we demonstrate a triggered single-photon source operating at the telecom C-band with photon extraction efficiency exceeding any reported values in this range. The non-classical light emission with low probability of the multiphoton events is realized with single InAs quantum dots (QDs) grown by molecular beam epitaxy and embedded directly in an InP matrix. Low QD spatial density on the order of 5 x 10(8) cm(-2) to similar to 2 x 10(9) cm(-2) and symmetric shape of these nanostructures together with spectral range of emission make them relevant for quantum communication applications. The engineering of extraction efficiency is realized by combining a bottom distributed Bragg reflector consisting of 25 pairs of InP/In0.53Ga0.37Al0.1 As layers and cylindrical photonic confinement structures. Realization of such a technologically non-demanding approach even in a non-deterministic fashion results in photon extraction efficiency of (13.3 +/- 2) % into 0.4 numerical aperture detection optics at approximately 1560 nm emission wavelength, i.e., close to the center of the telecom C-band.

Automated summary

In this work, a triggered single-photon source operating at the telecom C-band with the highest reported photon extraction efficiency has been demonstrated. The source consists of single InAs quantum dots grown by molecular beam epitaxy, suitable for quantum communication applications. The engineering of extraction efficiency is achieved through specific structures, resulting in high photon extraction efficiency at the telecom C-band.