[FarCenter]

The four-core fiber appears to have four small cores within the 125 micron cladding glass fiber as shown in this press release on previous work.

https://www.nict.go.jp/en/press/2021/07/12-1.html

The press release for the current experiment is at:

https://www.nict.go.jp/en/press/2022/05/30-1.html

While connectors could be used, I thought that fusion splicing was still the main technique used in splicing cables, such as after a dig up.

[TexasGator]

Thank you.