WDM systems in the C-band using Er(3+)-doped tellurite optical waveguide amplifiers

A 16-channel, 2.5 Gb/s, wavelength-division multiplexing system is analyzed with its channels allocated in the 1.52-1.56 mum wavelength region in order to increase the usable amplifier bandwidth to approximate to 45 nm. To avoid amplified spontaneous emission (ASE) noise and the nonuniform signal gain in the wavelength region, an amplifier module consisting of an Er(3+)-doped tellurite waveguide amplifier, an ASE filter, and two concatenated long-period grating filters are proposed. A tellurite-based amplifier was chosen as the amplifying element because of its broad emission bandwidth (similar to 80 nm), its high emission cross section (6.44x10(-25) m(2)), and its high rare-earth ion solubility. The amplifier model is based on propagation and population-rate equations and includes both uniform and pair-induced up-conversion mechanisms. It is solved numerically by combining finite elements and a Runge-Kutta algorithm. The analysis predicts that using the proposed amplifier module, the channels may be transmitted to a maximum distance of 1800 km, finding applications in large optical networks where either many wavelengths are required or channel spacing must be large.