Electromagnetic modeling of waveguide amplifier based on Nd(3+ )Si-rich SiO(2 )layers by means of the ADE-FDTD method

By means of ADE-FDTD method, this paper investigates the electromagnetic modelling of a rib-loaded waveguide composed of a Nd(3+ )doped Silicon Rich Silicon Oxide active layer sandwiched between a SiO(2 )bottom cladding and a SiO(2 )rib. The Auxilliary Differential Equations are the rate equations which govern the levels populations. The Finite Difference Time Domain (FDTD) scheme is used to solve the space and time dependent Maxwell equations which describe the electromagnetic field in a copropagating scheme of both pumping (λ(pump )= 488 nm) and signal (λ(signal )= 1064 nm) waves. Such systems are characterized by extremely different specific times such as the period of electromagnetic field ~ 10(-15 )s and the lifetimes of the electronic levels between ~ 10(-10)s and ~ 10(-4 )s. The time scaling method is used in addition to specific initial conditions in order to decrease the computational time. We show maps of the Poynting vector along the propagation direction as a function of the silicon nanograin (Si-ng) concentrations. A threshold value of 10(24 )Si-ng m(-3 )is extracted below which the pump wave can propagate so that a signal amplication is possible.