Research by Hub researchers from the University of Strathclyde, published today in npj Quantum Information, may guide the design and analysis of future satellite missions to establish quantum communications in space.
To overcome optical fibre range limitations and enable quantum-secure communications on continental, intercontinental and global scales, quantum communication technologies must be deployed in space via satellites.
The first realisations of satellite quantum key distribution (QKD) technologies are being rapidly developed, however, limited transmission times between satellite and ground station severely constrains the amount of secret key that can be obtained.
The researchers utilised published data from the Micius satellite, launched in 2016 by China, to model and analyse the effect of limited transmission times and the implications that these have on system design and operation. The data was used quantify practical performance limits of satellite QKD systems and examine the effects of link efficiency, background light, source quality, and overpass geometries to estimate long-term key generation capacity. Along with being used to inform the design and analysis of future missions, the findings may be used to establish performance benchmarks for both sources and detectors of quantum signals in space.
Speaking about their results, lead investigator, Dr Daniel Oi said:
“Space-based quantum communication has the potential to enable a globe-spanning quantum internet. Understanding how to build and operate satellite quantum key distribution systems is an initial step towards this goal. Our work highlights important considerations, especially compared with terrestrial fibre-based quantum links that are currently deployed.”
Lead author, Dr Jasminder Sidhu said:
“Limited transmission time is the ultimate constraint with satellites leading to fewer signals than possible with fibre-based networks. We explore how these constraints can influence mission design changes to improve coverage of each satellite.”
As part of its large programme of work to develop quantum security at all distance scales, the Quantum Communications Hub is developing a satellite QKD In-Orbit Demonstrator (IOD) which includes a CubeSat (small satellite) and an optical ground station, both of which will be fitted with Hub-developed quantum technologies. The findings of this paper will most certainly contribute to the design and analysis of that IOD.
For further information on the Hub’s satellite QKD IOD, visit the Hub website.