Strain-Controlled Quantum Dot Fine Structure for Entangled Photon Generation at 1550 nm.

Thomas Lettner,Klaus D Jöns,Katharina D Zeuner,Val Zwiller,Mattias Hammar,Lucas Schweickert,Stephan Steinhauer,Armando Rastelli,Samuel Gyger,Rinaldo Trotta,Carl Reuterskiöld Hedlund,Sandra Stroj

doi:10.1021/acs.nanolett.1c04024

Abstract

Entangled photon generation at 1550 nm in the telecom C-band is of critical importance as it enables the realization of quantum communication protocols over long distance using deployed telecommunication infrastructure. InAs epitaxial quantum dots have recently enabled on-demand generation of entangled photons in this wavelength range. However, time-dependent state evolution, caused by the fine-structure splitting, currently limits the fidelity to a specific entangled state. Here, we show fine-structure suppression for InAs quantum dots using micromachined piezoelectric actuators and demonstrate generation of highly entangled photons at 1550 nm. At the lowest fine-structure setting, we obtain a maximum fidelity of 90.0 ± 2.7% (concurrence of 87.5 ± 3.1%). The concurrence remains high also for moderate (weak) temporal filtering, with values close to 80% (50%), corresponding to 30% (80%) of collected photons, respectively. The presented fine-structure control opens the way for exploiting entangled photons from quantum dots in fiber-based quantum communication protocols.

Highlights

Entangled photon generation at 1550 nm in the telecom C-band is of critical importance as it enables the realization of quantum communication protocols over long distance using deployed telecommunication infrastructure
The presented fine-structure control opens the way for exploiting entangled photons from quantum dots in fiber-based quantum communication protocols
The generation of single and entangled photons in the telecom C-band (1530−1565 nm) is of great scientific and technological importance: operation in this wavelength range allows for compatibility with existing telecom infrastructure and long-range transmission due to the low losses in deployed optical fibers

Summary

Corresponding Authors

Samuel Gyger − Department of Applied Physics, KTH Royal Institute of Technology, 106 91 Stockholm, Sweden; orcid.org/0000-0003-2080-9897. Lucas Schweickert − Department of Applied Physics, KTH Royal Institute of Technology, 106 91 Stockholm, Sweden; orcid.org/0000-0002-1858-007X. Stephan Steinhauer − Department of Applied Physics, KTH Royal Institute of Technology, 106 91 Stockholm, Sweden; orcid.org/0000-0001-6875-6849. Mattias Hammar − Department of Electrical Engineering, KTH Royal Institute of Technology, 164 40 Kista, Sweden. Jöns − Department of Applied Physics, KTH Royal Institute of Technology, 106 91 Stockholm, Sweden; Present Address: Institute for Photonic Quantum Systems (PhoQS), Center for Optoelectronics and Photonics Paderborn (CeOPP), and Department of Physics, Paderborn University, 33 098 Paderborn, Germany; orcid.org/0000-0002-5814-7510.

■ ACKNOWLEDGMENTS

Findings

■ REFERENCES