Gain Characteristics of Lanthanum Co-Doped Erbium Fiber Amplifier

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 ions5~7, detailed gain characteristics of a Lanthanum co-doped Er/SiO2 fiber amplifier have not yet been clarified.