Splice Protection Sleeve

Depending on fiber’s application, different optical fiber coating designs exist. However, 250um UV coating is the most popular among today’s single mode and multimode bare fibers. The following illustration shows this common design. The polymer coating is a soft, UV cured, urethane acrylate. It has a higher refractive index than the cladding layer, so it can strip out unwanted light. This polymer coating may consist of one or two layers. If there are two layers, the inner layer is called primary coating and the outer layer is called secondary coating. The primary coating has a diameter of 180um. It is made of very soft acrylate to reduce fiber’s microbend loss. The secondary coating usually has a diameter of 250um and is made of much harder acrylate to provide good abrasion resistance.