Laser signals (visible and infrared light) can support data transfer at rates orders of magnitude higher than conventional radio frequency (RF) signals. That is why the majority of internet traffic travels as laser light through optical fibre networks rather than electrical signals through copper wire. Wireless communications, however, have remained in the realm of RF due to the challenges of free-space laser communications. This is a problem as the RF spectrum is a finite resource and has reached its practical limit. We are working to overcome these challenges, developing optical terminals for laser links between moving vehicles, as well constructing the TeraNet optical ground station network to support ground-to-space laser communications that will break the data transfer bottleneck imposed on spacecraft operators.
Topics include:
- Optical Ground Station Network Automation and Optimisation — A major weakness in laser communications is weather; lasers cannot propagate through clouds. The way around this is to use multiple optical ground stations (OGS) that overlap in their coverage but are far enough apart that the weather they experience is not correlated. This project would investigate how an OGS network can be automated and optimised.
- Atmospheric Mitigation — Atmospheric turbulence degrades an optical signal, reducing its capacity to transmit data. Adaptive optics (AO) is a mature technology used by astronomers to correct for this, but optical ground stations will need to operate under less favourable conditions than the pristine sites that astronomical observatories are located. This project would investigate various turbulence mitigation strategies for laser communications.
- Mobile Terrestrial Laser Communications — Laser communications can also be employed in terrestrial scenarios where high bandwidth and/or secure communications are needed, but optical fibre is impractical. This project would involve the design and implementation of optical terminals that could be vehicle-mounted and operate over links of ~20km.