Standard Fibers with end caps
The maximum power that can be guided within a fiber is mainly restricted by the power density at the fiber end-faces, when not considering bulk, nonlinear optical effects within the fiber, such as Brillouin scattering. Extreme power densities can cause scorching of the end-face or photo-contamination by the generation of a dipole trap.
Regular fiber without end cap
Fiber with end cap
Working with end cap fibers
Polarization extinction ratio of end cap fibers
The fiber cables with end caps made by Schäfter+Kirchhoff typically have a polarization extinction ≥ 200:1 (21 dB) or ≥ 400:1 (23 dB) for λ ≥ 780 nm. For more details on PM fibers please see here.
PCF Fibers with end caps
The fiber connectors of all PCF fiber cables are equipped with an end cap. This means that a short piece of coreless fiber (< 300 µm) is spliced onto the PCF fiber.
The end cap seals the microstructre of the fiber and allows for an easy cleaning of the end-face.
Additionally it also reduced the power density at the fiber end-face (see standard fibers).