I know that the core of a single-mode optical fiber is small (approximately 8 μm), because the core diameter is small, the light is propagated in one mode.
And I accidentally read this article which mentions a single-mode optical fiber with a large core: https://www.rp-photonics.com/large_core_fibers.html
I do not understand why a single-mode optical fiber has a large core ? What is the purpose of this fiber, transfer communication or energy ? With a large core, is light propagated in one mode ?
I would love to know the answer. Please help me. Thank you !