Optical fiber drawing tower

Figure 1 Schematic of an optical fiber drawing tower. GPa...

Step 6— Testing. Often the coated fiber is continuously proof-tested for strength on the draw tower or as it is rewound onto other spools. Optical testing is also critically important. For multimode fibers the tests include attenuation, bandwidth, numerical aperture, and core diameter for single mode they include such additional characteristics as chromatic dispersion, cutoff wavelength, and mode field diameter. 

---