kjernediameter

kjernediameter is a Danish term used in engineering and science to denote the diameter of the central region, or core, of a cylindrical object. The core is typically the part responsible for the primary function and properties of the item, with outer layers or sheaths providing support, protection, or insulation. The exact meaning of kjernediameter is context-dependent, and it is used across disciplines to distinguish the core from surrounding material.

In optical fiber technology, the kjernediameter refers to the core diameter, a key parameter that governs light propagation. Single-mode fibers typically have a small core, around 8 to 10 micrometers, while multimode fibers use larger cores, commonly 50 to 62.5 micrometers. The core is surrounded by cladding with a lower refractive index, enabling total internal reflection and guiding the light along the fiber. The core diameter affects coupling efficiency, bandwidth, and modal behavior.

Beyond optics, the term can describe the core diameter of other cylindrical components, such as reactor cores in energy systems or cores of cables and sensors. In each case, kjernediameter influences performance characteristics like neutron flux, heat removal, impedance, or mechanical fit. Measurement is performed with tools appropriate to scale, ranging from calipers or micrometers for larger cores to optical or electron microscopy for microscopic cores, often with traceability to calibration standards.

See also: core, diameter, optical fiber core diameter.