Introduction and general concepts; Propagation in optical fibres; Waveguiding (ray and electromagnetic approaches); Dispersion; Attenuation; Polarization effects; Rayleigh, Brillouin and Raman scatterings; Nonlinear effects; Application: monitoring of a fibre link using an OTDR; Passive optical components; Generalities on components; Couplers; Isolators and circulators; Optical filters; Fibre Bragg gratings; Optical switching; Lasers and optical receivers; Semiconductor laser diode; Common Photodetectors; Optical amplification; Erbium-doped fiber amplifiers; Raman amplifiers; Optical modulation; Direct and external modulations; Optical modulators; Intensity modulation formats; Performance analysis for a direct detection scheme; Direct detection scheme; Fiber-loss-induced limitations; Dispersion-induced limitations; Noise-induced limitations; Link budget calculation.