Researchers pack 19 cores into standard fibre

An international research collaboration has packed a record number of cores into a standard-cladding optical fibre, which they demonstrated by seeing a speed record – 1.7 petabit per second – over 67km.

Visualisation of the 19-core fibre
NICT Japan

The researchers from Japan’s National Institute for Information and Communication Technology (NICT) worked with Sumitomo Electric, the Eindhoven University of Technology, the University of L’Aquila, and Australia's Macquarie University.

According to NICT’s media release, the team “developed a 19-core optical fibre with a standard cladding diameter (0.125 mm)”, which it said is the largest number of cores packaged in the standard cladding diameter.

The 0.125mm cladding means the 19-core fibre is compatible with current manufacturing technology.

Sumitomo designed and fabricated the core, and NICT constructed the transmission system for the demonstration.

Macquarie University developed a 3D laser-printed core multiplexer demultiplexer that interfaces the 19-core fibre with single-core fibres, which then connect to standard transmission equipment.

"At Macquarie University, we've created a compact glass chip with a waveguide pattern etched into it by a 3D laser printing technology,” Dr Simon Gross from Macquarie’s School of Engineering said.

“It allows feeding of signals into the 19 individual cores of the fibre simultaneously with uniform low losses. Other approaches are lossy and limited in the number of cores.”

Dr Gross said the technology could be in use in submarine cables in five to 10 years.

NICT said the fibre can reduce the digital processing power needed in submarine cables, compared to multi-mode fibre transmission.

The results of the experiment were presented to the 46th Optical Fibre Communication Conference in March.