Detailed evaluation of an attainable repeater spacing for fibre transmission at 1.3 ¿m and 1.55 ¿m wavelengths

An attainable repeater spacing at 1.3 ¿m and 1.55 ¿m wavelengths using a step-index monomode fibre cable is given, after detailed consideration of total loss as well as total dispersion of an optical fibre. The longest attainable repeater spacing at 1 Gb/s is about 100 km at 1.55 ¿m wavelength using a single-mode laser diode and a monomode fibre with a relatively small core-cladding refractive index difference, e.g. about 0.2%.