Introduction to optical fibers. Learning the principles and methods for measuring properties of optical fiber components and systems. Description of optical fibre technology: chemical vapour deposition (MCVD, OVD, VAD), rod-in-tube, crucible methods. Presentation of the vitreous material and the polymers used to manufacture optical fibers. Practical examples of the optical fibers co-doped with lanthanides. Measurement parameters for the construction of active fiber amplifiers, fiber lasers and broadband sources. Measurements of optical parameters and physical fiber: birefringent, photonics, nonlinear, capillary. Characterisation of the construction, operation and parameters for the constructions of active fiber amplifiers, fiber lasers and broadband sources.