Single mode fiber optic cable
Singlemode
Singlemode fiber optic cable has a small core and only one pathway of light. With only a single wavelength of light passing through its core, singlemode realigns the light toward the center of the core instead of simply bouncing it off the edge of the core as with multimode.
Singlemode fiber optic cable is typically used in long-haul network connections spread out over extended areas–longer than a few miles. For example, telcos use it for connections between switching offices. Singlemode cable features a 9-micron glass core.