Francis Bennet, Australian National University; Oliver Thearle, Australian National University; Lyle Roberts, Australian National University; Jordan Smith, Australian National University; James Spollard, Australian National University; Daniel Shaddock, Australian National University; Ping Koy Lam, Australian National University
Keywords: Adaptive optics, quantum key distribution, optical communication
Abstract:
The Australian National University have been developing a quantum communication instrument with adaptive optics (AO) to achieve free-space Quantum Key Distribution (QKD). With organisations such as SpaceX and OneWeb planning on launching constellations of satellites for high-speed global communication, this provides an opportunity for innovative and disruptive technologies to be adopted for such endeavours. There is a need for secure, high-bandwidth communications for both civilian and defence use, to support the growth of ever-connected technologies and missions.
The ultimate goal of this research is the development of ultra-secure global communications networks enabled by quantum encryption and quantum key distribution. A key capability in such a global network is ground-to-satellite and satellite-to-satellite quantum communications requiring robust quantum-enabled ground-stations and satellite capability. We have combined expertise in AO, optical telescopes, and astronomical instrumentation from the ANU Research School of Astronomy and Astrophysics, with expertise in quantum technologies and free-space laser links at the ANU Department of Quantum Science, to develop an optical ground station to support quantum communication.
We utilise continuous-variable QKD, a technology which does not rely on detecting single photons and hence uses a much less complex detection system, and is also compatible with existing communication technologies such as fibre optics and free space links. This enables existing classical communication networks can be converted into a continuous-variable QKD system. Continuous-variable QKD system can be multiplexed, where multiple quantum channels can be simultaneously used with the same transmit and receive technologies, resulting in much higher data transfer rate. AO compensates the effects of atmospheric distortion to maximise the quality of the optical link, thereby reducing atmospheric turbulence induced loss and noise at the receiver. An AO system measures the distorted wavefront caused by atmospheric turbulence with a wavefront sensor, and corrects these distortions with a device such as a deformable mirror. This restores the optical quality of the optical system, and allows the quantum state to be transmitted and detected after transmission through a turbulent atmosphere.
We present the development and first results of an optical ground station with AO for horizontal propagation, and plans for testing QKD transmission to space.
Date of Conference: September 11-14, 2018
Track: Adaptive Optics & Imaging