BT on Tuesday announced that it has kicked off trials of a new type of optical fibre - hollow core fibre - at the BT Labs in Adastral Park, Ipswich, in a collaborative project with Lumenisity, a Southampton University spin out company, and Open Radio Access Network (O-RAN) mobile vendor Mavenir.
BT researchers are conducting the trials at BT’s research and engineering campus, using a 10-kilometre-long hollow core fibre cable provided by Lumenisity; this new type of network cable has a hollow, air filled centre that runs the entire length of the cable. It will be used to test a variety of use cases, including potential benefits for 5G networks and ultra-secure communications, like Quantum Key Distribution (QKD).
Networks across the world currently run on single-mode optical fibre, pioneered at Adastral Park, which consists of solid strands of glass. The glass in these cables quickly carries information over long distances by channelling light from laser transmitters through the glass strands. However, the nature of glass means that this light travels marginally slower inside the fibre than it would in air.
Research into hollow core fibre presents an opportunity to explore how the capabilities of optical fibre can be enhanced in future, with the potential to reduce the latency, or signal delay, caused by the light travelling through glass, by up to 50%. This new fibre has an air-filled central core, with an outer ring of glass, to guide the laser beam whilst maintaining the signal speed at very close to the ultimate speed of light.
The reduction in the delay of the light provided by hollow core fibre would enable a variety of benefits, from high frequency trading to lowering mobile network costs. Working with Mavenir, BT has shown that using hollow core fibre can increase the distance between street antennas and the back-end processing in exchanges. Due to the low latencies, use of hollow core in the Radio Access Network (RAN) could reduce mobile network costs by allowing more 5G antennas to be served from one exchange or cabinet.
John Baker, Mavenir’s Senior Vice President Business Development
The ability to extend the reach of fibre connected radios only further demonstrates the power of Open RAN and its Eco System. This improvement will significantly increase the number of use cases that can be served from containerised cloud based Open RAN solution.
