loose tube fiber
The compact core is a constructive design of optical waveguides. In this optical waveguide, the secondary cladding is not firmly attached to the fiber, but loosely encases the optical waveguide.
The cladding may consist of one or more plastic layers with a gel between them, similar to the hollow core but with smaller gaps.
The radial fiber clearance is only a few hundredths of a millimeter. The outer diameter of the compact core is identical to that of the solid core. The advantages of the compact core over the solid core are its better strippability and its minimal influence due to microbending and temperature effects.