Abstract

The Er³⁺-doped optical fibre amplifier (EDFA) has stimulated much interest for possible application in future communication systems, since its gain band coincides with the third telecommunications window of silica fibre at a wavelength of 1.55μm^1,2. Although Stark-splitting of the ground and metastable levels in erbium-doped glass generates a wide spectral bandwidth in an EDFA, its gain spectrum is typically irregular, with a sharp peak around 1.53μm and a broad band with reduced gain to longer wavelengths (see Figure 1, Curve A). Although the amplifier can be operated at wavelengths away from the peak gain³, disadvantages occur due to increased spontaneous-spontaneous beat noise and possible laser action at the peak gain wavelength.

© 1990 Optical Society of America