Coherent pluggable optics are starting to move beyond metro and regional data-center links toward much longer fiber routes, including submarine networks.

In a new Nokia technical post published October 12, the company says the latest 800ZR/ZR+ generation is extending the reach and efficiency of router-pluggable optics as AI and cloud networks demand more bandwidth.

The clearest subsea proof so far is still at 400G rather than 800G. Nokia researchers reported a 5,682-kilometer submarine-cable demonstration carrying 400 Gb/s per wavelength with coherent pluggable optics. The result shows that the small router-mounted form factor can operate far beyond its original metro data-center role.

The shift matters because pluggables can reduce the need for separate optical transport hardware on some routes. They do not eliminate dedicated subsea systems, amplifiers or engineering requirements, especially on the longest links.

For more context, see our coverage of undersea cable manufacturing, submarine cable repair and wavelength-division multiplexing.