Design of high gain Er3+-Yb3+-Ce3+ co-doped ZELA waveguide amplifier

This paper reports an accurate design of Er3+-Yb3+-Ce3+ doped ZrF4-ErF3-LaF3-AlF3 (ZELA) fluoride glass channel amplifier operating in the third window of the telecommunication systems. By considering measured spectroscopic and optical parameters, we demonstrate the feasibility of a novel optical waveguide amplifier exhibiting high gain and low noise figure. The electromagnetic investigation has been carried-out by employing a full-vector Finite Element Method (FEM) solver. The mode electromagnetic field, calculated at different wavelengths, constitutes the input data for the home-made numerical code which solves both the power propagation and population rate equations via a Runge-Kutta based iterative algorithm. The dependence of the up-conversion coefficients on erbium concentration are taken into account. In the simulations, the core shape, the waveguide length, the input pump and signal powers, the erbium and the ytterbium concentration are varied with the aim to optimize the amplifier performance. The goal of achieving high gain with a short device length is demonstrated. In particular, the simulation results show that the waveguide amplifier exhibits an optimal internal gain value close to 22.5 dB and a noise figure of 4.1 dB for a waveguide amplifier 5.5 cm long, an erbium concentration of NEr=2.5×1026 ions/m3, ytterbium concentration NYb=2.4×1026 ions/m3, NCe=6×1026 ions/m3, an input pump power Pp=100 mW and an input signal power Ps=1 μW.