Terminology related to Optical Fibers

Core-cladding concentricity error is defined as the distance of the center position between the core and cladding. Smaller core-cladding concentricity error is preferable for minimizing splice/connector loss.

Cladding diameter is defined as the outer diameter of the optical fiber's glass section, which is the vertical red line in the diagram.

Cladding non-circularity is defined in the figure.

Fiber curl describes a tendency of optical fiber to curve along their length when released from winding on a spool, which affects the splice quality.
Fiber curl radius is defined as the radius of curvature.

Coating diameter is the outer diameter of optical fiber’s protecting layer which is made of acrylates which is the vertical blue line in the figure.

Coating-cladding concentricity error is the relative position of the cladding against the coating in an optical fiber.

Attenuation describes the reduction of optical signal power, and is defined as ratio of the optical power at two points, typically expressed as the logarithm of the ratio in decibel (dB).
For optical fiber, attenuation per unit length, e.g. dB per kilometer (dB/km), is typically used as the attenuation coefficient.
Lower attenuation can directly improve the optical signal ratio (OSNR) for large capacity and long distance transmission systems.
Sumitomo Electric offers ultra-low attenuation optical fibers.

The wavelength at which the chromatic dispersion becomes zero. For ITU-T G.652 and G.657 fibers, zero-dispersion wavelength is within 1300-1324 nm.

Slope of the chromatic dispersion versus wavelength curve.

Zero dispersion slope is the chromatic dispersion slope at the zero dispersion wavelength.