Toward Optical Switching and Routing in Non-Terrestrial Networks: Challenges and Opportunities

As the demand for ever more capacity, coverage and reach rapidly increases in next generation mobile networks, terrestrial fiber networks are envisioned to be increasingly deployed in tandem with the non-terrestrial networks, where the link transmission is based on free space optics (FSO), and their radio frequency link (RF) counterparts. On High Altitude Platform Systems (HAPSs), such as airships or balloons, it is expected that FSO and RF transmission technology are to be deployed in parallel based on weather. For inter-satellite communications, on the other hand, FSO links are likely to be a dominant communication link technology. All networking functions on-board a satellite, or HAPS, are however still implemented in electronics, including switching and routing. The next innovation frontier for non-terrestrial networking is to expanding its capabilities toward ultra-high-speed all-optical switching and routing, thus creating the optical NTN continuum. This article elaborates on state of the art in non-terrestrial optical networking, including HAPS and satellite, and discusses challenges and opportunities in control and data planes for spaceborne all-optical switching and routing. We provide an overview of related open-source efforts and share the vision of innovation through collaboration.