This could potentially pave the way towards ultrafast and reconfigurable on-chip RF systems with advantages in compactness, low power consumption, low fabrication complexity, flexibility and compatibility with existing RF functionalities.
"By creating fast tuneable delay lines on chip, one can provide broader bandwidth instantaneously to more users,” PhD candidate Yang Liu said. “The ability to rapidly control RF signals is crucial for applications in both our daily life and defence.
"For example, to reduce power consumption and maximise reception range for future mobile communications, RF signals need to achieve directional and fast distributions to different cellular users from information centres, instead of spreading signal energy in all directions."
By optically varying the control signal at gigahertz speeds, the time delay of the RF signal can be amplified and switched at the same speed.
According to the team, optical platforms have been limited in performance by a low tuning speed offered by on-chip heaters, with side effects of fabrication complexity and power consumption.
"To circumvent these problems, we developed a simple technique based on optical control with response time faster than one nanosecond," said Liu.
"Such a system will be crucial not only to safeguard our defence capabilities, it will also help foster the so-called wireless revolution," Professor Benjamin Eggleton added.
"We are currently working on more advanced silicon devices that are highly integrated and can be used in small mobile devices.”