(CATQER) reported the first transfer of a
quantum key in Australia. In 5 years of subse-
quent research CATQER extended its Free
Space Quantum Communications Test Bed
from the laboratory bench out to a distance of
43 km with the assistance of colleagues from
Canberra-based optical instrumentation compa-
nies CH & AH Zelman and Electro Optic
Systems, The University of NSW at the
Australian Defence Force Academy, Monash
University, the Canberra Institute of Tech-
nology, and the Australian Surveying and Land
Information Group.
In 2004 we reported successfully transferring
polarised infrared qubits at a rate of 100 bits per
second with an error rate of less than 3% over a
distance of 26 km using the B92 quantum key
protocol invented by Charles Bennett of IBM
Yorktown in 1992. In the final 2005 trials, Alice
transmitted qubits from Little Burra in NSW, south of
Canberra, to Bob at Wallaroo 40 km to the north. These simu-
lations confirmed the feasibility of nocturnal satellite QKD at
elevations greater than about 40° above the horizon, limited
by atmospheric turbulence and attenuation of the qubit beam.
Shortly later, the CATQER group was disbanded when The
University of Canberra closed its communications engineering
school. Its work on a quantum key courier satellites ceased.
Other satellite QKD proposals from European and US groups,
notably the University of Vienna group, were also stillborn,
although several groups including the University of Padua and
the National University of Singapore have recently begun
limited quantum satellite experiments.
Others successfully commercialised their research and devel-
oped optical fibre QKD links and related hardware and software
products. An alternative method of key distribution called contin-
uous variable QKD was developed at the Australian National
University, and was later commercialised for local network use
in banking and other secure working environments.
Now, more than two decades after the initial research into
free-space quantum cryptography, Austrian and Chinese
quantum researchers have successfully collaborated in a tech-
nological tour de force that promises to revolutionise cryp-
tography on a global scale and, as well, to address fundamental
aspects of quantum physics that challenge current conceptions
of reality.
Of course, because of the heavy security classification of govern-
mental research in this field, we do not know for sure that the
Chinese QUESS group was the first to deploy a QKD satellite!
Em/Prof Paul J. Edwards was Director of the Centre for Advanced Telecommunications &
Quantum Electronics Research at The University of Canberra.24 ||MAY/JUNE 2017
Time-lapse frame sequence of laser tracking of Micius from Xinglong Observatory.
Credit: Yingwei Cheng / Spaceweather.comBob was equipped with a qubit receiver comprising optical fibre-
connected astronomical telescopes, polarisers, a cooled semi-
conductor single-photon counter and digital analyser. Credit: A. BlakeIn 2005 Alice transmitted qubits from Little Burra in NSW, south
of Canberra, to Bob at Wallaroo 40 km to the north. Credit: P. Zelman