Broadband emitter localization and prefabrication two-photon interference from InAs/InP quantum dots monolithically grown on an InGaAsP/InP distributed Bragg reflector
We demonstrate a monolithic telecom C-band single-photon platform based on low-density InAs/InP quantum dots grown on an InGaAsP/InP distributed Bragg reflector, with simulated upward light-extraction efficiency exceeding 10% within the 40 nm spectral band. Enhanced light extraction is crucial for wide-field photoluminescence imaging, enabling approximately 3 nm statistical centroid-localization precision of QD emitters due to improved signal-to-noise ratio. The identified charged exciton emitting at 1549.5 nm exhibits single-photon emission purity up to 94.7%, validated by a raw peak-area integration under pulsed quasi-resonant excitation. Under these conditions, photons emitted sequentially from the unprocessed planar structure reveal a raw two-photon interference visibility of 51% of the photon wave packet within the 2 ns time window and 41% over a 4 ns integration window, all without Purcell enhancement typical for cavity-embedded emitters. Combining broadband extraction, high photon coherence, and emitter preselection on a native III-V wafer, this architecture paves the way for marker-based deterministic fabrication of high-quality monolithic nanophotonic devices.