Scientists have developed a quantum LED that can emit single photons at telecommunication wavelengths. Such single-photon emitters will be crucial in the development of quantum communication networks.
One of the major technical challenges for the development of things like a quantum internet, communication, and cryptography is the manufacture and deployment of a network of quantum satellites and other infrastructure.
Another crucial component for future quantum optic networks is highly-efficient light sources that emit single photons, one by one.
Thanks to the work of a research team at Toshiba Research Europe Limited, the University of Sheffield, and the University of Cambridge, we can now check that off the quantum obstacles list.
The Problem of Creating Quantum Networks
Researchers working on quantum computing technology and quantum communication are investigating the use of single photons as information carriers. In this project, they had a double challenge to deal with.
The first technical challenge they faced is that quantum sources need to be able to emit single light quantas as well as entangled photon pairs.
To add to the complexity, quantum photon emitters need to operate at certain wavelength bands to be useful for quantum telecommunication.
Scientists already came up with quantum light diodes that emit single and entangled photon pairs.
However, they mainly operate at short wavelengths that can’t be used in fiber-optic based quantum communication. There are five optical wavelength bands suitable for telecommunication: O, E, S, C, and L bands comprised between 1300 and 1600 nanometers.
Quantum LEDs as a Telecommunications Solution
Ideally, a quantum light-emitting diode should be able to emit a single photon on demand and in a defined wavelength band.
Now a research team from the University of Sheffield, and the University of Cambridge have made just that double engineering feat.
“For the first time,” Tina Müller, co-leader of the research, said: “quantum devices can meet the fundamental requirements of state-of-the-art quantum key distribution and quantum communication systems.”
The new quantum LED, based on a semiconductor called indium phosphide, emits single light quantas that, with a band wavelength around 1,550 nm, fall within the C band (1530-1565 nm).
The quantum LED study appeared in Nature Communications. This new quantum single photon-emitting device will serve as a material platform for future applications-oriented quantum telecom hardware.
Even with this massive breakthrough, the work is far from finished. The research team intends to optimize their quantum LED in terms of efficiency and size to make it ready for direct integration into existing quantum networks.