Er doped Si nanoclusters waveguides longitudinally pumped by broad area lasers for optical amplification

We present an extensive study of an Er doped Silicon Rich Silicon Oxide (SRSO) based material used for the realization of optical waveguide amplifiers in which Si-nanoclusters (Si-ncls) are formed by thermal annealing. In particular we focus our attention on the confined carrier absorption (CCA) mechanism within the Si-ncls and on the fraction of Er ions coupled to them. Experimental data are used for accurate modeling of Si-ncls sensitized EDWAs (Erbium Doped Waveguide Amplifiers) longitudinally pumped by visible broad area lasers. Although the material requires further optimization to be effectively deployed, accurate numerical simulations of Si-ncls sensitized EDWAs, based on this material and longitudinally pumped by visible broad area lasers at 660 nm, point out significant benefits provided by the nanoclusters sensitization. Our model, based on the Finite Element Method, performs the modal analysis of the guiding structure, and then allows to study the propagation of pump and signal electric fields along the waveguide amplifier; the rate equations for the coupled Er/Si-ncls system account for their coupling ratio. Numerical results, based on measured material parameters, point out that resonant pumping at 660 nm provides significant benefits in terms of gain enhancement, with respect to standard EDWAs, even at low Er/Si-ncls coupling ratio. This feature suggests that a careful design can lead to the realization of compact integrated amplifiers and lasers, compatible with CMOS technology.