Fiber with a modified index profile, often a low-index trench around the core, that holds light in through tight bends. Singlemode versions are graded G.657.A1, A2, B2 and B3, rated for minimum bend radii of 10, 7.5, 7.5 and 5 mm respectively, and the A grades meet G.652.D and splice to standard fiber. It makes staple-down drops and inside-corner routing in apartments practical without the loss spikes ordinary fiber shows.
Use the bend-insensitive drop for the MDU risers, the installers are going to staple it around door frames whether we like it or not.
Bend-insensitive fiber hides bends from the VFL and the fiber identifier too, because little light leaks out where you clip or bend it.
Also heard as
- BIF
- bend-optimized fiber
Related terms
Macrobend
A bend in a fiber tight enough to see, which lets light escape the core and causes loss.
Bend radius
The tightest curve a fiber or cable can take without extra loss or damage, stated separately for pulling and at rest.
Mode field diameter
The effective width of the light spot traveling in a singlemode fiber, slightly larger than the physical core.
Drop
The final fiber cable run from a distribution terminal on the street to a single customer building.