Abstract

Recent progress on erbium-doped fiber amplifiers (EDFAs) and their application to optical communications has been very rapid since the EDFA has many advantages such as polarisation-insensitive high gain, a low noisefigure, and low insertion loss.¹ It is well known that in order to obtain a broader and relatively flatter gain profile, Aluminum (Al₂O₃) is co-doped into the core of the fibers.^2,3 To make a wavelength independent flat gain profile is very important from the viewpoint of ultrashort pulse amplification and wavelength division multiplexing technique. Payne and Laming investigated a Borolanthanate co-doped EDFA.⁴ Although LaF₃ or La₂O₃ were used as hosts for Nd ions^5~7, detailed gain characteristics of a Lanthanum co-doped Er/SiO₂ fiber amplifier have not yet been clarified.

© 1991 Optical Society of America