A novel scheme is proposed to obviously improve the amplified gain, gain flatness and bandwidth characteristics of
FOPA by applying a cascaded fiber structure. The basic structure of the cascaded fiber optical parametric amplifier
(CFOPA) is introduced. Then, the expression of signals pass gain characteristic is obtained by utilizing a set of coupled
equations. The gain, bandwidth and gain flatness characteristics of the CFOPA with the different parameters of DCF,
such as fiber length l/, dispersion slope dD//dλ, and so on, are theoretical analyzed and optimized. Furthermore,
simulation analysis is applied to verify the theoretical results by using Optisystem 7.0 software. Although, there are a
few deviations between the simulation and the theoretical results, the simulation results effectively demonstrate the
validity and feasibility of the theoretical analysis.