A team of researchers from the ARC Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS) in the University of Sydney’s Australian Institute for Nanoscale Science and Technology have managed to accomplish radio frequency signal control at sub-nanosecond time scales on a chip-scale optical device.
Radio frequency (RF) is a specific range of electromagnetic wave frequencies, extensively used for communications and radar signals. This breakthrough research is very likely to influence today’s wireless revolution.
The details of the research have been published in the high-impact journal Optica today.
CUDOS and School of Physics PhD candidate at the University of Sydney, lead author Yang Liu, said the new research that could release the bandwidth bottleneck encountered by wireless networks globally was performed at the headquarters of the Australian Institute for Nanoscale Science and Technology (AINST), the $150m Sydney Nanoscience Hub.
Nowadays, there are 10 billion mobile devices connected to the wireless network (reported by Cisco last year) and all require bandwidth and capacity. By creating very fast tunable delay lines on chip, one eventually can provide broader bandwidth instantaneously to more users. The ability of rapidly controlling RF signal is a crucial performance for applications in both our daily life and defence. For example, to reduce power consumption and maximize reception range for future mobile communications, RF signals need to achieve directional and fast distributions to different cellular users from information centers, instead of spreading signal energy in all directions.
Yang Liu, PhD candidate, School of Physics, University of Sydney
The lack of the high tuning speed in existing RF method in advanced communications and defense has triggered off the development of solutions on a compact optical platform. These optical counterparts had been usually limited in performance by a low tuning speed on the order of milliseconds (1/1000 of a second) provided by on-chip heaters, with side effects of power consumption and fabrication complexity.
“To circumvent these problems, we developed a simple technique based on optical control with response time faster than one nanosecond: a billionth of a second – this is a million times faster than thermal heating,” said Mr Liu.
CUDOS Director and co-author Professor Benjamin Eggleton, who also heads the Nanoscale Photonics Circuits AINST flagship, said the technology would not only be significant for developing more efficient radars to detect enemy attacks but would also make major improvements for all.
Such a system will be crucial not only to safeguard our defence capabilities, it will also help foster the so-called wireless revolution – where more and more devices are connected to the wireless network. This includes the internet of things, fifth generation (5G) communications, and smart home and smart cities. Silicon photonics, the technology that underpins this advance, is progressing very quickly, finding applications in datacentres right now. We expect the applications of this work will happen within a decade in order to provide a solution to the wireless bandwidth problem. We are currently working on the more advanced silicon devices that are highly integrated and can be used in small mobile devices.
Professor Benjamin Eggleton, CUDOS Director
It is possible for the time delay of the RF signal to be amplified and switched at the same speed by optically changing the control signal at gigahertz speeds.
Mr Liu and fellow researchers Dr Amol Choudhary, Dr David Marpaung and Professor Benjamin Eggleton accomplished this on an integrated photonic chip, opening the door towards ultrafast and reconfigurable on-chip RF systems with unparalleled benefits in low power consumption, compactness, flexibility, low fabrication complexity, and compatibility with current RF functionalities.
The research builds on study supported by the Australian Research Council through CUDOS, a Centre of Excellence.